Upload
others
View
3
Download
0
Embed Size (px)
Citation preview
Renewable Energy Guidelines
Volume 12
Pakistan Poverty Alleviation Fund, Islamabad
Civil Works in Rural Power Supply Systems
Copyright © Pakistan Poverty Alleviation Fund – 2013
Reproduction is authorized provided the source is acknowledged and provided a reference copy is being sent to
PPAF and the reproduction is not sold.
For further information: Pakistan Poverty Alleviation Fund, www.ppaf.org.pk
Note: The information contained within this document has been developed within a specific scope and might be
up‐dated in the future.
The Renewable Energy Guideline Series has been developed by the German‐Pakistan project “Development of
Hydropower and Renewable Energy (HRE) in Khyber‐Pakhtunkhwa”, funded by German Development Bank
(KfW) on behalf of “Ministry for Economic Cooperation and Development” (BMZ).
Pakistan Poverty Alleviation Fund (PPAF)
Project team:
Mr. Zaffar Pervez Sabri
Senior Group Head, Public Goods and Services
Mr. Kamal Afridi
General Manager, Water, Energy & Climate Change
Mr. Shaukat Ali
Renewable Energy Specialist
Contact address:
1‐Hill View Road, Banigalla, Islamabad
PAKISTAN
E‐mail: [email protected]
Phone: (+92‐51) 261 3935‐50
Name of Consultants:
INTEGRATION
Team:
Dr. Ulrich Frings ‐ Team Leader
Mr. Sher Khan – Deputy Team Leader
www.integration.org
Authors:
Sher Khan
Ulrich Frings
Date: November, 2013
Renewable Energy Guidelines Nov. 2013 i
Volume 12 Civil Works
Guidelines & Manuals
Volume 1: Life Cycle Cost Analysis in MHP Planning
Volume 2: Community Contribution Aspects in Rural Power Supply Systems
Volume 3: General Design Criteria on MHPs
Volume 4: Design Aspects of Community PV Systems
Volume 5: Operation & Maintenance Aspects of MHPs
Volume 6: Quality Assurance & Control of Civil Works
Volume 7: Health, Safety & Environmental Aspects in Civil Works
Volume 8: Transmission & Distribution in Rural Power Supply Systems Design ‐ Specification ‐ Installation
Volume 9: Electro‐Mechanical Equipment for MHPs Design ‐ Specification ‐ Installation
Volume 10: Commissioning Guidelines PV ‐ MHP
Volume 11: Micro/Mini Hydropower Design Aspects
Volume 12: Civil Works in Rural Power Supply Systems
ii Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
Table of Contents 1 Introduction ................................................................................................................................ 1
1.1 Standards ............................................................................................................................ 1 1.2 Drawings ............................................................................................................................. 1 1.3 Temporary works ................................................................................................................ 2 1.4 Programme of works and methods of construction ........................................................... 2 1.5 Reporting ............................................................................................................................ 3
2 Site and preparatory works ........................................................................................................ 4 2.1 Mobilization/demobilization .............................................................................................. 4 2.2 Temporary facilities ............................................................................................................ 4 2.3 Preparatory works .............................................................................................................. 5 2.4 Site clearance ...................................................................................................................... 6
3 Earth works ................................................................................................................................. 9 3.1 General ................................................................................................................................ 9 3.2 Excavation ......................................................................................................................... 11 3.3 Materials ........................................................................................................................... 16 3.4 Backfilling .......................................................................................................................... 18 3.5 Embankments ................................................................................................................... 20 3.6 Testing of earth works ...................................................................................................... 22 3.7 Geotextiles ........................................................................................................................ 24 3.8 Geomembranes ................................................................................................................ 25 3.9 Drainage ............................................................................................................................ 26
4 Concrete works ......................................................................................................................... 27 4.1 General .............................................................................................................................. 27 4.2 Materials ........................................................................................................................... 30 4.3 Concrete ............................................................................................................................ 31 4.4 Reinforcement .................................................................................................................. 33 4.5 Formwork .......................................................................................................................... 35 4.6 Joints ................................................................................................................................. 37 4.7 Concreting ......................................................................................................................... 42 4.8 Pre‐cast concrete .............................................................................................................. 46 4.9 Concrete for benching ...................................................................................................... 46 4.10 Pumping concrete ............................................................................................................. 46 4.11 Inspection and testing ....................................................................................................... 47 4.12 Cutting and testing of core samples ................................................................................. 48
5 Building works .......................................................................................................................... 50 5.1 General .............................................................................................................................. 50 5.2 Masonry works .................................................................................................................. 50 5.3 Plastering .......................................................................................................................... 53 5.4 Screeds .............................................................................................................................. 55 5.5 Flooring ............................................................................................................................. 56 5.6 Roofing .............................................................................................................................. 59 5.7 Timber works .................................................................................................................... 61 5.8 Metal windows and doors ................................................................................................ 62 5.9 Hardware .......................................................................................................................... 63 5.10 Sanitary installation .......................................................................................................... 64 5.11 Painting ............................................................................................................................. 67 5.12 Electrical works ................................................................................................................. 75 5.13 Permanent buildings ......................................................................................................... 75
6 Roads and Pavements .............................................................................................................. 78 6.1 Formation and sub‐grade ................................................................................................. 78
Renewable Energy Guidelines Nov. 2013 iii
Volume 12 Civil Works
6.2 Sub‐base and road base .....................................................................................................78 6.3 Sealing of surfaces .............................................................................................................78 6.4 Bituminous road surfaces ..................................................................................................79
7 Metalwork and steel structures ............................................................................................... 80 7.1 Scope ..................................................................................................................................80 7.2 General ..............................................................................................................................80 7.3 Design and detailing ..........................................................................................................80 7.4 Welding and heat treatment .............................................................................................80 7.5 Flooring ..............................................................................................................................81 7.6 Handrailing .........................................................................................................................82 7.7 Laddering and stairways ....................................................................................................82 7.8 Miscellaneous ....................................................................................................................83 7.9 Protection of metal surfaces of steel structures ...............................................................83
8 Pipeworks ................................................................................................................................. 86 8.1 Materials ............................................................................................................................86
9 Fencing ..................................................................................................................................... 89 9.1 General ..............................................................................................................................89 9.2 Standard fencing ................................................................................................................89 9.3 Security fencing .................................................................................................................89 9.4 Gates ..................................................................................................................................90 9.5 Installation .........................................................................................................................90
10 Electric motors of hydraulic steel works and cranes ................................................................ 91 10.1 General ..............................................................................................................................91 10.2 Voltage and rating .............................................................................................................91 10.3 Starting ...............................................................................................................................91 10.4 Insulation class ...................................................................................................................92 10.5 Ventilation and type of enclosure .....................................................................................92 10.6 Bearings .............................................................................................................................92 10.7 Control ...............................................................................................................................92 10.8 Tests ...................................................................................................................................92
11 Environment and community ................................................................................................... 93 11.1 Public relations ..................................................................................................................93 11.2 Employment .......................................................................................................................93 11.3 Land interests ....................................................................................................................93 11.4 Protection against damage ................................................................................................93 11.5 Watercourses .....................................................................................................................93 11.6 Waste disposal ...................................................................................................................93 11.7 Final clean‐up and landscaping ..........................................................................................94
12 Tests on completion, commissioning and acceptance ............................................................. 95 12.1 Tests ...................................................................................................................................95 12.2 Inspection and testing during construction .......................................................................95 12.3 Tests on completion and handing‐over procedure ...........................................................96
iv Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
List of tables Table 3‐1: Gabion basket requirements .............................................................................................. 17 Table 4‐1: Classes of concrete ............................................................................................................. 28 Table 4‐2: Water stops requirements ................................................................................................. 40 Table 5‐1: Earthing conductor size ...................................................................................................... 76
Acronyms and abbreviations
A Ampere AC Alternating Current AKRSP Aga Khan Rural Support program ACSR Aluminium Conductor Steel reinforced CDM Clean Development Mechanism CO Community Organizations DC Direct Current EC European Commission ELC Electronic Load Controller E&M Electro‐mechanic FDC Flow Duration Curve GI Galvanized Iron GIS Geographic Information System GIZ German Technical Cooperation GOs Government Organization GPS Global Positioning System HDPE High Density Polyethylene H&S Health & Safety hrs hours HV High Voltage Hz Hertz (frequency unit) INGOs International Non Governmental Organization KfW German Development Bank kW Kilo Watt kWh Kilo Watt Hour kV Kilo Volt LED Light‐Emitting Diode Lit Liter LSOs Local Support Organizations LT Low Tension LV Low Voltage MCB Moulded Circuit Breaker MCCB Moulded Case Circuit Breaker MDPE Medium Density Polyethylene MHP Mini/micro Hydropower Plant MSDS Material Safety Data Sheets NGOs Non‐Governmental Organizations O&M Operation and Maintenance PF Power Factor PCD Pitch Circle Diameter PPAF Pakistan Poverty Alleviation Fund POs Partner Organizations (COs) PPIB Private Power Infrastructure Board PURE Productive Use of Renewable Energy PPE Personal Protective Equipment PV Photovoltaics PVC Polyvenylchloride
Renewable Energy Guidelines Nov. 2013 v
Volume 12 Civil Works
SM Social Mobilizer SRSP Sarhad Rural Support Program RCBO Residual Current Breaker with Overload Protection SSLS Solar Street/home Lighting System Rs. Pakistani Rupees T&D Transmission and Distribution TOP Terms of Partnership V Volt WOs Women Organizations XLPE Cross‐linked polyethylene
Renewable Energy Guidelines Nov. 2013 1
Volume 12 Civil Works
1 Introduction
The Manual on “Site Organization and Execution of Civil Works” shall support the Community
Organizations (COs) and Partner Organizations (POs) in their construction works. They shall carry out all
work in a skilled and workman like manner in compliance with modern methods of engineering. All
design; calculations, materials, works, manufacture and testing shall conform to the latest applicable
standards.
These guidelines provide general standards of design and material to be supplied and work to be carried
out by the CO(s). Mentioning of any specific material or plant does not necessarily imply that such is
included in the Works.
All Works shall, unless otherwise specified, comply with the various Standards mentioned and working
methods described.
The names of the manufacturers of materials proposed for incorporation in the Works, shall be
furnished by the CO(s), when so requested by the PPAF and PO Engineer who shall have power to reject
any parts, which in his/her opinion are unsatisfactory or not in compliance with the respective
Specification or Standard.
The construction works can only be started after all documents (e.g. feasibility study, design, structural
calculations, design drawings) are approved by PPAF.
1.1 Standards
The Civil Works shall comply as a minimum with International Standards ISO, EN, DIN, BS Standards
(International Standards Organization, EN European Norm, DIN German Standards, BS British
Standards). Where no Standards are specified, the above defined EN, BS or DIN shall apply. Where there
is conflict between below Specifications and the relevant Norm, the Specifications shall take
precedence.
Works of any nature, not specifically mentioned in the Terms of Partnership (TOP), however necessary
for the Permanent Works subject of project design and TOP, shall be executed as per state of the art.
Materials supplied and work performed shall comply with these Standards and regulations as a
minimum. If other Standards are used, the Standards shall be equal or superior to those specified and
full details of the difference shall be supplied to the PPAF and PO Engineer by CO for approval, before
consideration.
1.2 Drawings
1.2.1 Project drawings
The work shall conform to the proposed drawings of sub‐project(s), all of which form as part of the TOP
signed between the PO and CO(s).
The drawings are intended to show the proposed general arrangement, dimensions and materials of the
intake structures, settling basin, power channel, fore‐bay, powerhouse, tail race, turbines, generators
and auxiliaries. The final design of the powerhouse shall be modified by the PO in so far as practicable to
suit the equipment furnished and layout plans recommended by the E&M manufacturer.
2 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
1.2.2 Design and drawings by the PO
The PO shall prepare the design and drawings which will be reviewed by the PPAF, and identify and
point out inconsistencies and/or omissions in the drawings and correct these in consultation with the PO
Engineers. All dimensions in drawings, calculations and information furnished in connection with the
TOP shall be expressed preferably in metric SI units. Design work to be furnished by the PO shall include all hydraulic and structural engineering drawings for all structures and works. It shall include, but
not limited to;
architectural drawings
formwork and reinforcement,
welding plans,
steel structures,
excavation stability calculations and drawings.
If any revision is required in the approved drawings by the CO and PO, the same shall require to be
approved again by PPAF and revised drawings shall bear a revision number.
PPAF's approval of the construction drawings and designs shall not relieve the CO and PO of the
obligation to meet the terms of the Specification and any of the plant which upon delivery to site is
found to be incorrect or unsatisfactory, or which fails to perform its duty satisfactorily during
commissioning or during the Defects Notification Period shall be replaced to the PPAF's satisfaction.
The CO and PO shall be responsible for any discrepancies, errors, or omissions in the drawings and other
particulars supplied by them, whether such drawings and particulars have been approved by the PPAF
or not, provided that such discrepancies, errors, or omissions are not due to inaccurate information or
particulars furnished in writing to the CO/PO by the PPAF. The PO shall be responsible for drawings and
information supplied in writing by the PPAF and for the details of special work specified by them.
1.3 Temporary works
The CO shall design at his own expense all Temporary Works they may require for the execution of the
Works.
Unless provided for in the Bill of Quantities expenditures whatsoever dealing with any Temporary Works
shall be deemed to be covered by the other rates and prices in the Bill of Quantities.
1.4 Programme of works and methods of construction
The CO shall present his operation and construction programme to the PO Engineer and PPAF. The
Engineer shall review this programme and approve it or reject it, with reasons for rejection. In case of
rejection a revised version of the programme shall then be re‐submitted by the CO.
The possible simultaneous construction of adjacent works under separate contracts may require the CO
to adapt his planning to that of E&M Contractor. The PO will inform the E&M Contractor in due time
about the conditions to be expected during the period of Contract.
Further to the Conditions, the programme of Works shall include but not be limited to the following
items:
Proposed dates for starting and completing the construction of the various parts and stages of the
Works.
Renewable Energy Guidelines Nov. 2013 3
Volume 12 Civil Works
Proposed dates for procuring materials, mobilization of the main plant required to complete the Works.
Proposed hours of Site works for CO personnel.
Proposed system of CO access and work roads and Site plan.
The CO shall submit to the PO Engineer every month copies of a detailed planning for the next month
describing the Work they intend to perform in that period. These documents must include description of
the proposed methods of construction. The PO Engineer shall approve or reject (with reasons for
rejection) the proposed methods of construction within one week.
Any consent of the PO Engineer to this planning shall not exempt the CO of his responsibility to
complete the Works within the time as agreed and stated in the TOP.
1.5 Reporting
The PO Engineer will keep a diary on the Site in which all his remarks, instructions, decisions and the
essential details of the Works shall be recorded. The CO shall assist in keeping the diary by supplying
daily, any information on the Works requested by the Engineer.
Apart from the diary, the reporting system includes daily, weekly and monthly working reports. The daily
reports are kept on site while the weekly and monthly reports are to be sent within 2 days to the PO and
PPAF. A detailed description of reports and respective contents is compiled in Volume 6 of the HRE
Guidelines.
4 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
2 Site and preparatory works
2.1 Mobilization/demobilization
Mobilization at site shall include the erection of all site facilities and the furnishing of all equipment as
necessary to carry out the Works under the TOP.
The CO shall ensure at all times that items set up for building into the Works are not damaged or
displaced from their correct position and alignment.
Completed Works, temporary Works, Works under progress and materials which shall be carefully
protected from rain, flood, heat, air‐borne dust, humidity, or other deteriorating influences.
The CO shall be responsible for appropriate security measures that protect the site and labor working on
site.
The demobilization shall include the removal of all site facilities and temporary installations, the
demobilization of all equipment from site, the removal of all surplus materials, the reinstatement of all
damaged or worn public, private and access roads and facilities used by the CO and the cleaning up of
the construction site after completion of the Works.
2.2 Temporary facilities
2.2.1 General
The CO shall supply a detail design specifying all temporary facilities that they intend to organize on Site
‐ stores, workshops, temporary and access roads, water, power and sewerage supply Services etc.‐ to
the PO Engineer for approval.
2.2.2 Temporary office
A temporary Office for the PO and CO, shall be established in proximity to or on the site and shall be
adequately furnished, and maintained in a clean, orderly condition by the CO for the duration of
construction. The CO representatives shall be present in the office and/or at work site at all times while
Work is in progress.
2.2.3 Sanitary arrangements
The CO(s) shall provide and maintain temporary sanitary facilities on the site for the use of all persons
connected with the Works. The CO(s) shall keep the site in a clean and sanitary condition, and shall post
notices and take such precautions as may be necessary to keep the site clean. The CO(s) shall carry out
any cleaning whatsoever as may be directed by the PO Engineer to maintain such sanitary conditions.
2.2.4 Name boards
The CO(s) shall erect name boards featuring the minimum dimensions of PPAF standards stating the
Project Name, the Employer, the Financing Agency, Cost, the CO and the Construction Period. The site /
name boards shall be easily visible and of a durable type and be installed within 02 months of
Commencement day.
Renewable Energy Guidelines Nov. 2013 5
Volume 12 Civil Works
2.2.5 Maintenance of traffic
The CO (s) shall provide, erect and maintain on the site and the locations on the access to the site all
traffic signs and traffic control Signals, as necessary for the safe direction and control of the traffic. The
location and size of all such signs and the lettering thereon shall be approved by the PO Engineer before
erection of the signs. The CO(s) shall reposition, cover or remove signs as required during the progress
of the Works.
2.3 Preparatory works
2.3.1 Site inspections
Before carrying out any works, the Site shall be inspected jointly by the CO and the PO Engineer in order
to verify site conditions, to establish the directions for site clearance and to clarify the further
proceedings. Before commencing any site clearance and excavation in private property, the CO shall
prepare and agree with the owner(s) of such property a record of the state of the surface and/or
structures with particular reference to any features that may require special care, conservation and
reinstatement.
2.3.2 Survey works
2.3.2.1 Setting‐out of works
The CO(s) under the directives of PO Engineer shall set out and establish suitable pegs, benchmarks,
reference points and grid lines necessary for the setting out of the works. The Works shall be set out and
tied to the Regional Coordinate and Level System, which will be handed over by the PO to the CO(s). The
PO Engineer will assist the CO(s) to establish temporary benchmarks and survey stations at suitable
locations on the Site of the Works and during the progress of the Works shall periodically check the
levels of the benchmarks and the coordinates of the stations against the original points lines and levels
of reference.
Before commencement of structural works, the CO shall establish, in a position to be approved by the
PO Engineer steel datum pegs, which shall be securely concreted in. The level of this peg shall be
established and agreed with the Engineer and used as reference datum in the construction of the
Works.
The PO shall prepare drawings showing the locations and levels or coordinates as appropriate of each
and every temporary benchmark and survey Station used for the setting out of the Works.
The PO Engineer shall identify setting out dimensions for all structures by relating them to existing
facilities and by Interpretation of the Documentation. The levels of weirs, inverts of channels and other
hydraulic structures shall be as shown on the drawings unless otherwise required or approved by the
PPAF.
The locations of structures to be constructed as part of the Works shall be identified by reference to
steel pins set in concrete or other approved markers set up by the CO(s), who shall also determine the
co‐ordinates of the markers and their distances from adjacent existing structures.
2.3.2.2 Survey labor
The CO(s) shall also provide all labor, instruments and materials as may be required by the PO Engineer's
for survey work and measurements in connection with the Work.
6 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
2.3.3 Protection of existing structures and utilities
The CO(s) shall assume full responsibility for the protection of all buildings, structures and utilities,
public or private including poles, signs, services to buildings, utilities in the street, water pipes, hydrants,
drains and electric and telephone ducts and conduits, whether or not they are shown on the drawings.
The CO(s) shall carefully support and protect all such structures and utilities from injury of any kind. Any
damage resulting from the CO’s operations shall be repaired at their expense.
The CO(s) shall bear full responsibility for obtaining all locations of underground structures and utilities.
Services to buildings shall be maintained, and any costs or charges resulting from damage thereto shall
be paid by the CO(s).
The CO(s) shall not demolish or remove any existing buildings, structures or other objects including
trees, whether indicated on the Drawings or not, unless on a specific instruction from the PO Engineer.
The CO(s) shall take every care and precaution to protect from damage any of these objects, including
houses, buildings, fences or trees, which are situated on or near the Site(s).
Any property situated in close proximity to the Works shall be protected against any damage which
could be caused by vehicles, subsidence, vibration, etc. Any damage caused shall be repaired by the
CO(s) at their expense to conform to the condition of the property prior to damage and to the
satisfaction of the PO Engineer. The trunk of trees located close to working areas shall be fully protected
with wooden boards.
2.3.4 Works in private property
Before commencing any site clearance and excavation in private property, the CO(s) shall prepare and
agree with the owner or occupier of such property a record of the state of the surface with particular
reference to any features that may require special care, conservation and reinstatement. The records
shall be drawn up in collaboration with the PO Engineer who shall also be supplied with copies of all
such Statements and records.
2.3.5 Precautions
The CO(s) shall take all precautions to avoid damage to any structure owned by other parties. If damage
should occur, the owner of the damaged structure should be contacted immediately, jointly by the CO(s)
and the PO Engineer, and all necessary repairs shall be made by the CO(s) under the direction of the
owner and to the original state.
2.4 Site clearance
All areas of the site, marked on drawings for clearance or from which material has to be excavated or
upon which fillings have to be deposited shall be leveled and be cleared from all debris, all obstructions
and all vegetation except trees marked for conservation. Excess materials obtained from site clearance
shall be disposed off the site at locations to be found by the CO(s) and approved by the PO Engineer
2.4.1 Trees and roots
Where directed by the PO Engineer, trees shall be uprooted or cut down as near to subsoil level as
possible. Branches and foliage shall be disposed off the site at locations to be found by the CO as
suggested by the PO Engineer. Stumps or roots whether existing or remaining after the felling of trees
shall, where directed by the Engineer, be grubbed out and disposed off the site at locations to be found
by the CO. The resulting hole shall be filled with approved material and well compacted.
Renewable Energy Guidelines Nov. 2013 7
Volume 12 Civil Works
Any damage to the canopy of trees of girth greater than 900 mm shall be treated at the COs expense as
promptly as possible after the damage occurring or on instructions from the PO Engineer.
Replacement trees and hedges shall be planted in the appropriate season and shall be replaced at the
CO's expense if they fail or are damaged as a result of the construction activities
2.4.2 Land drains
Land drains, which cross excavations shall be reinstated using flexibly jointed rigid pipes to
accommodate settlement and to ensure that groundwater will not be diverted into the backfilled
excavations.
Stone drains shall be reinstated using 20 mm clean stone. The trench shall be lined and covered with a
porous geotextile before backfilling with subsoil and top soil.
2.4.3 Stripping of top soil
Topsoil shall be stripped from the site where the works are being constructed, where site vehicles travel,
where bulk materials are stored or as otherwise directed by the PO Engineer or provided in the TOP or
in accordance with the design. Topsoil shall be stripped from the whole working area as directed by the
PO Engineer and shall be stored in tidy, stable and well drained stockpiles until required for later use.
All surface areas for which stripping of top soil has not been ordered, but has been disturbed by the
construction operations shall be reinstated, to the original condition including providing and placing of
top soil to a minimum thickness of 15 cm.
Topsoil shall be stockpiled on the site in Stacks not more than 1.5 m high and shall not be traversed by
any plant. The stock‐piles of topsoil shall be grasses and kept free of weeds by treatment with a foliar
acting herbicide. Topsoil stripped from pipeline/access easements shall not be transported out of the
field from which it was taken without permission of the Engineer.
2.4.4 Demolition works
Existing buildings and structures on site which the PO Engineer may order to be demolished or may be
required to be removed for the construction of the permanent works shall be demolished to the extent
necessary to construct the various units of work.
The work shall be carried out in such a manner as to cause as little inconvenience as possible to the
occupants of adjoining premises and the public. The debris shall be sprinkled with water to prevent dust
arising. The CO(s) shall provide all requisite shoring and strutting or other supports incidental to the
demolition work, remove debris from site and finally clear the site and make good all parts of the work
which are disturbed.
2.4.5 Disposal of excess material
Subject to any specific requirements of the TOP the disposition of excavated material shall be at the
CO's discretion but shall be arranged as to suit the overall requirements for the Construction of the
Works.
The CO(s) shall ensure that no excavated material, which is suitable for or required for reuse in the
Works is disposed off outside the Site.
8 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
The CO(s) shall make their own arrangements for the disposal of unsuitable surplus material from any
Site. The CO(s) will be entirely responsible for its removal from the site and its ultimate disposal in
accordance with environmental needs.
Renewable Energy Guidelines Nov. 2013 9
Volume 12 Civil Works
3 Earth works
3.1 General
Earth Works as specified hereunder shall include the location of underground structures, the
preparation of the site including protective fencing, excavation including strutting, sheeting, bracing and
protection of slopes, diversion of surface water and ground water removal, trimming, disposal of
excavated materials off site, backfilling including delivery of backfill material and site clearance including
disposal of surplus material.
The CO shall be deemed to have fully satisfied himself as to the occurrence of surface and subsurface
obstructions and the exact nature of the ground conditions and his prices shall include allowances for
working in these or any other materials with all artificial or natural obstructions, foreseen or
unforeseen. Any alteration of works due to unexpected site conditions or the removal of obstructions
shall not affect the lump sum prices quoted for earth works.
3.1.1 Standards
The CO(s) under supervision of PO shall carry out works described in accordance with the appropriate
DIN Standards or equivalent. The main standards are, but are not limited by, the following:
DIN 4124 Excavation and trenches, slopes, breadths of working spaces, planking and strutting
DIN 18300 General technical code for earthworks
DIN 18303 General technical code for excavation lining
DIN 18305 Groundwater management
The CO(s) may carry out the works or provide materials in accordance to local or other international
Standards, provided their requirements are superior or equivalent to the quality described by the
standards cited in the Specifications.
3.1.2 Classification of soils
For classification of soil following categories shall be used in order to identify the soil for purposes of
excavation and refill, until specific specifications and instruction given by the Engineer and PPAF:
Soil Categories (DIN 18300)
Class 1 Top soil
Class 2 Soils with liquid or very plastic consistency (wet clay soils, organic)
Class 3 Easily breakable soils (sands, gravel, gravel‐sand up to 15% Ø < 0,06 mm maximum 30% stones Ø > 63 mm)
Class 4 Medium breakable soil
(Mixtures of sand, gravel, clay > 15% Ø < 0,06 mm maximum 30% stones Ø > 63 mm)
Class 5 Difficult breakable soils (Soils of Class 3 and 4 with more than 30% stones Ø > 63 mm)
Class 6 Easily breakable rock and similar fissured rock and soils of Class 4 and 5, hard consistency
Class 7 Difficult breakable rock Rock of high density, very little fissured and fractured.
10 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
3.1.3 Excavation methods
The following terms shall apply to Specification Clauses in which reference is made to excavations:
Normal Excavation means excavation in open cut (excluding trench excavation) down to levels specified on drawings or otherwise as being the general levels after completion or excavation other than incidental excavation.
Trench Excavation means excavation, to levels and limits specified on drawings or otherwise, of trenches in which pipes or the like are to be laid
Incidental Excavation means excavation in small quantities below or outside the limits of normal excavation and trench excavation, but excluding excess excavation.
General Excavation means excavation, whether normal or incidental, required for structures, roadwork's and borrow areas
Excess Excavation means excavation outside the limits specified for normal, trench or incidental excavation. Excess excavation shall not qualify for any extra payment.
3.1.4 Backfill materials
The following terms shall apply to Specification Clauses in which reference is made to backfilling of
excavations:
Unsuitable Material means material not suitable for backfilling including materials from swamps, organic and perishable materials, clay and soils with high placidity indices.
Rock Fill shall consist of hard un‐weathered material of suitable size for deposition and compaction and may comprise broken stone, hard brick, concrete or other comparably hard inert material
Selected Fill for backfilling trenches, pits and foundations shall comprise uniform readily compatible material free from roots, vegetable matter, building rubbish and clay lumps.
3.1.5 Location and protection of underground utilities
The CO(s) shall be responsible for locating and protecting all underground structures and utilities. They
shall proceed with caution in all excavation so that the exact location of underground structures and
utilities, either known or unknown, may be determined and he shall be held responsible and to pay for
the repair of such structures when broken or otherwise damaged.
When removal, relocation or reconstruction of any cables, pipes or any other services whatsoever is
necessary for the pursuit of the TOP, the CO(s) shall notify the PO Engineer in writing. All work in
connection with the removal or resetting of these or any services shall be carried out by the CO and
under the supervision of the Engineer or concerned field supervisor.
3.1.6 Maintaining of public services
The CO(s) will be held responsible for maintaining the public Services. Any damages caused by his
operations shall be repaired without any delay Existing Services shall be maintained during the
execution of works at their own expense.
Renewable Energy Guidelines Nov. 2013 11
Volume 12 Civil Works
3.2 Excavation
The CO(s) shall examine the site and familiarize themself with the nature of ground, the excavation
methods to be applied and physical obstructions that may affect the work. The use of explosives will be
permitted only with the consent of the PO Engineer and/or site supervisor.
The CO(s) shall not execute any excavation without having the Engineer's prior approval to the methods
which he proposes to employ. They shall not modify such methods thereafter without the Engineer's
consent.
3.2.1 General excavation
General excavation, e.g. normal, mass or incidental excavation, as required for structures and road work
shall be carried out to the grade of the bottom of the structure. Where instructed by the Engineer, areas
beneath structures may be over‐excavated.
General excavation will be carried out after site clearance and the stripping of subsoil. In their design,
the CO(s) shall indicate the limits of excavations to be made for the erection of the individual structures.
The prices quoted for general excavation shall be fully inclusive and contain all incidental works as:
excavation of any type of ground including rock, whether this excavation has to be made by hand, by machine or by explosives;
over excavation, if ordered by the engineer, and making good the same;
demolition of existing surfaces and underground structures, where required;
location, maintaining and reinstatement of existing services, where required;
supporting excavations and temporary support of the sides of excavations;
keeping free the excavation from surface and ground water;
trimming, compacting and protecting of formation levels;
any additional excavation to accommodate temporary supports and all working space to carry out the work;
disposal of excavated material whether it shall be reused for backfilling or removed as surplus material off site including formation of all temporary spoil heaps and all double handling necessary;
protection of the works and all additional measures necessary to ensure that the excavated location is maintained in a safe and workmanlike manner.
The CO(s) shall not use explosives during demolition of any structures or for the removal or excavation
of hard materials during earthworks operations without prior approval of the Engineer. All hard material
shall preferably be removed using mechanical or hydraulic breakers.
Excavations shall be carried out in accordance to DIN 4124 (October 2002) and DIN 18303.
For excavations deeper than 2.0 meters, the CO(s) shall submit the structural design inclusive the
relevant design calculations of the sheeting/bracing System to the Engineer for approval.
Excavation bottoms shall be cleared of projections such as rocks, stones, roots and the like.
3.2.2 Excavation with explosives
Prior to excavating rock by explosives at a given location the CO(s) shall, after notifying the Engineer or
site supervisor, carry out a survey of the surface of the rock as agreed by the Engineer.
12 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
Before commencing any drilling and blasting the CO(s) shall submit for the Engineer’s approval the
drilling, charging and ignition patterns he proposes to use. Such approval shall, however, not exempt the
CO(s) of the full liability of any blasting operations.
The drilling equipment shall include a device for measuring the direction of drilling.
In order to minimise over break and requirements for rock support, perimeter blasting shall be
performed forwards in all final rock surfaces.
The length and size of blast rounds shall be regulated according to the prevailing rock conditions. When
deemed necessary from stability considerations, the PO Engineer can order reduced round lengths
and/or subdivision of the cross‐section.
When deemed necessary from stability considerations, the PO Engineer can order change in excavation
shape, both the arch height and the symmetry, within the given cross‐sectional area.
Design drawings show the theoretical rock contour. Special rock mass conditions could require cross‐
section adjustments, which shall be decided and/or approved by the Engineer.
3.2.3 Excavation tolerances
The excavated area shall at no point be less than the theoretical area for each section given on the
Drawings. Rock protrusions inside theoretical contour lines are not accepted.
If the CO(s) considers it necessary to request for excavation outside theoretical contour to obtain access
for temporary works, such request shall be forwarded to the Engineer.
Perimeter Blasting a)
Perimeter blasting shall be applied on contours in order to ensure smooth final surfaces, minimise
overbreak and reduce the subsequent support measures. Smooth blasting or pre‐splitting may be
applied.
This includes drilling of contour holes c/c 700 mm with max. diameter Ø 50 mm and use of special low
strength explosives. The row next to contour holes may also require charge limitations.
As a general rule the distance between the perimeter and the nearest row of holes of the main round
shall be 1.3 times the spacing of perimeter holes for smooth blasting. For pre‐splitting this distance shall
be 0.5 times the burden in the main round, or smaller than the average joint spacing.
The selection of these and other pertinent parameters shall be based on experience gained from the
initial rounds, and shall be subject to the approval of the Engineer.
Smooth Blasting b)
The result of smooth blasting is governed by the following parameters:
the diameter of the contour holes
the spacing of contour holes
the distance between the row of contour holes and the next row of holes (burden)
the type and size of charges used
the ignition pattern.
This method is based on closely spaced contour holes, with reduced charges to be fired as a final clean‐
blast after the main round on the last number of delays. The method shall prevent extensive fracturing
of the rock mass beyond the contour.
Renewable Energy Guidelines Nov. 2013 13
Volume 12 Civil Works
Pre‐splitting c)
The principle of pre‐splitting differs from that of smooth blasting mainly by its ignition pattern. The
contour holes are blasted prior to the main round, and the crack formed should act as a barrier, which
will tend to limit further fracturing of the rock mass beyond the contour from the vibrations of the main
round.
3.2.4 Further and excess excavation
When the specified levels or limits of excavation are reached and approved by the PO Engineer, he will
inspect the subsoil exposed and may, if he considers any part of the subsoil unsuitable, direct the CO(s)
to excavate further. Such further excavation shall be refilled to the specified levels or limits with
approved imported material or concrete class C 12/15.
Any excess excavation outside the specified "payment limits", and any further excavation which has not
been ordered by the PO Engineer shall be held to be excess excavation which will not be paid for.
The CO(s) shall, at their own expense, remove from the site all material resulting from excess excavation
and shall make good the same with such kind of fill material or concrete as may be reasonably required
by the PO Engineer having regard to the circumstances.
3.2.5 Keeping excavations free from water
The CO(s) shall keep all excavations free from water and sewage, whether caused by floods, storms or
otherwise, so as to construct the works in dry conditions.
The CO(s) shall keep infiltrating or accumulated water at a level lower than the bottom of the
permanent work for such a period as required by the provisions of the Specification and the CO's
method of construction.
The mode of drainage proposed by the CO(s) is subject to the approval of the PO Engineer. Any sub‐
drainage below the permanent works shall, if left in place, be sealed with concrete or other approved
material. Sub‐drains underneath permanent concrete structures shall be covered with water‐proof
membranes.
3.2.6 Field drains
Should any existing subsoil or field drains be uncovered during general excavation, the CO(s) shall either
carefully replace them when backfilling, or, if this is impracticable, shall divert them to new drains or
ditches, or otherwise relay them as the PO Engineer may direct.
3.2.7 Grouting of rock
If rock surfaces after excavation to required level display fissures or cracks, these shall be grouted with a
mixture of cement, water and aggregate up to a depth of at least 1 m. The method and materials for
grouting shall require the approval of the PO Engineer.
3.2.8 Trial holes
The PO Engineer may direct that trial holes shall be excavated well ahead of excavation to such depths
as he shall order to determine the location of works. Such excavation shall be held to be incidental
excavation.
14 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
3.2.9 Supporting excavations
The CO(s) shall support the sides and the ends of all excavations to prevent any fall or run from any
portion of the ground outside the excavation and to prevent settlement or damage to structures
adjacent to the excavation. The CO(s) shall provide, install and maintain all materials necessary to
provide such support.
If, for any reason, any portion of the bottom, sides and ends of any excavation shall give way, the CO(s)
shall take all necessary remedial measures including the excavation and removal of all the subsoil
thereby disturbed at both, inside and outside the nominal limits of excavations.
Where the CO proposes to perform excavations with sloping faces and without shoring, the excavated
faces shall be to stable slopes and heights. Full details on the execution shall be submitted to the
Engineer for approval.
3.2.10 Shoring/bracing
When the material being excavated has sliding planes inclined towards the trench, adequate
shoring/bracing must be carried out immediately after excavation. Particular care shall be taken if the
earth, though firm, may be rendered unstable when excavated or by rain or seepage of groundwater.
If the width of the excavation is unavoidably increased by slipping or collapsing of the sides, work shall
be suspended and the Engineer informed on the occurrence. The method of shoring to be used is up to
the discretion of the CO(s), but subject to the approval of the Engineer with regard to safety. The CO(s)
will be fully responsible for the stability and the effectiveness of the shoring. Costs for shoring shall be
included in the rates and prices for excavation
3.2.11 Maintaining of other services and structures
The CO(s) shall be responsible for maintaining all water courses, pipes, sewers, drains, gas pipelines,
electricity and communication cables, other Services and structures during the construction of the works
and for any remedial measures necessary to make good any damage arising out of the execution of the
works. He shall temporarily support or divert and subsequently reinstate all such services and structures
to the satisfaction of the Engineer or the concerned authorities.
As soon as an existing Service is encountered in the excavation the CO(s) shall forthwith call the
attention of the Engineer and the appropriate utilities service authority thereto.
Where permanent diversion or support is rendered necessary as the unavoidable result of the
construction of the works in accordance with the TOP, or where in the opinion of the PO Engineer the
position of existing services warrants temporary diversion or support, the Engineer will instruct the
CO(s) accordingly.
Notwithstanding any relevant information furnished by the PPAF or the PO Engineer, the CO(s) shall be
responsible for ascertaining, from his own inspection of the site and from the respective supply
authorities and other public bodies and by excavating trial pits, the position of all mains, pipes and
cables whether underground or overhead, within or near the site.
3.2.12 Measurement of excavations
After levelling and Clearing the site under the Works, the CO(s) shall take and record levels of any such
part, in the manner specified or as agreed by the PO Engineer. Such levels, when agreed by the
Renewable Energy Guidelines Nov. 2013 15
Volume 12 Civil Works
Engineer, are the basis for measurement. The CO(s) shall also take and record such other levels and
dimensions as are necessary during the process of excavation.
General excavation, whether normal or incidental, required for structures and roadwork will be
measured net. Where normal payment limits of general excavation are not shown on drawings or not
otherwise specified, they shall be deemed to be the minimum net limits, which would allow the outline
of the completed structure to be lowered vertically from subsoil level into its final position. In addition
allowances will be made in the measurement for the working space required according to DIN and the
safety regulations and the backfilling of such space.
The excavation in intermediate and hard rock material etc. shall be quoted as extra over items.
3.2.13 Disposal of excavated material
Disposal method
Subject to any specific requirements of the CO(s) the disposition of excavated material shall be at the
CO's discretion but shall be arranged as to suit the overall requirements for the Construction of the
Works.
The term "excavation" shall be deemed to include for disposing of excavated materials within the site
and off‐site.
Excavated material, which is not required or not suitable for reuse in the Works shall be disposed off‐
site at locations to be found by the CO(s) and by the PPAF. Excavated material shall only be disposed off‐
site with the agreement of the PO Engineer.
Disposal on site
Disposing of excavated materials within the site shall be executed in any of the following ways upon
direction of the PO Engineer:
transporting and placing in temporary stockpiles and backfilling to excava¬tions including any a)doubling handling of materials; or
transporting and placing of approved materials in permanent stockpiles, including the shaping and b)drainage of such tips; or
transporting of selected excavated materials to locations within the site for embankments and filling c)around structures including tipping for spreading and compaction.
Stockpiles on site
Only materials which are approved by the PO Engineer shall be placed in various stockpiles. No tree
trunks, stumps, roots, foliage or rubbish of any kind shall be placed in stockpiles.
Temporary stockpiles to store excavated materials shall be arranged by the CO(s) upon approval and
direction of the Engineer. Such stockpiles shall be shaped as to maintain stability and good drainage at
all times. Topsoil stripped from the site shall be stored in separate stockpiles for later use in
reinstatement and landscaping.
Disposal of excavated material off site
Excavated material, which is not required or not suitable for reuse in the Works shall be disposed off‐
site at locations to be found by the CO(s) and approved by the PO Employer.
The materials to be disposed off‐site shall become the property of the CO(s) and they shall be entirely
responsible for its removal from the site and its ultimate disposal.
16 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
3.3 Materials
3.3.1 Filling materials
The selection of backfill material is subject to the approval of the PO Engineer. Fill material shall be, if
not specified otherwise, selected and broken in such manner that no particle exceeds one half of the
thickness of the layer for compaction. It shall contain all sizes of material distributed from the largest
permitted to the smallest grain diameter.
Fill material shall not contain gap‐graded materials, except with the written approval of the Engineer for
such case. It shall be free of organic, soluble or other deleterious materials. The fill material, if not
specified otherwise, shall not contain stones, rocks or concrete fragments larger than 50 mm in any
dimension and shall have a plasticity index of less than 10 and a minimum dry density of 1.6 t/m³
according to modified Proctor density.
Should the material selected as filling become unacceptable to the Engineer for any reason including
exposure to weather conditions, contamination and segregation during the progress of the Works, the
CO(s) shall remove such damaged, softened or segregated material and replace it by fresh approved
material at his own expense.
3.3.2 Drainage fill and filter materials
Free drainage fill and filter material shall be formed of hard durable particles and shall be free from clay,
silt, soluble or organic matter. The particle size distribution shall be in accordance to the filter rules set
out by Terzaghi.
Materials shall be provided by the CO(s) from approved sources. The CO(s) may use material from
excavation, provided it is suitable and processed in compliance with the specification for free drainage
material.
3.3.3 Rip rap
Rip rap material shall be sound, unweathered and with low water absorption capacity in order to avoid
cracking, bursting and dripping as a result of weather influences. The rock shall mainly consist of large
pieces with lateral lengths from 150 to 400 mm and smaller parts to secure the boulders against sliding
and to provide stability to the fill structure. The density of rip rap material shall be not less than 2.2 t/m³
(solid volume without voids) and each piece of rip rap shall have is greatest dimension not large than
twice its least dimension.
The material delivered shall be dumped and graded off to a uniform surface up the lines and grades
shown on approved drawings. No pockets of rocks and clusters of large blocks will be permitted. The
CO(s) shall submit full details of the proposed source, certified test results and samples for the approval
of the PO Engineer.
3.3.4 Stone pitching
The material used in stone pitching shall be obtained by the CO(s) from sources approved by the
Engineer. The stone shall be sound, durable and hard. It shall be free from laminations, weak cleavages
and undesirable weathering and shall be of such properties that it will not disintegrate from the action
of air, water or in handling and placing.
The dimensions of stones shall range between 200 to 400 mm and above. The minimum plain
dimensions shall be of less than two thirds of the maximum plane dimension for each stone. The stones
Renewable Energy Guidelines Nov. 2013 17
Volume 12 Civil Works
will be rough hammered dressed, so that they fit reasonably close together. They shall be laid to a true
and even surface, the spaces between the stones being clinked with spalls. The density of stones shall
be not less than 2.2 t/m³ (solid volume without voids).
3.3.5 Box gabions and gabion mats
General a)
The gabion box and mattress shall normally be machine‐woven hexagonal units made from double twist
hexagonal mesh of heavy galvanized mild steel wire. Hand‐woven gabions shall only be used with the
approval of the Engineer, if they can be shown to meet the standard.
All edges of the standard gabions including diaphragms, if any, shall be mechanically selvedged in such a
way as to prevent unraveling of the mesh and for developing the full strength of the mesh.
Where irregular‐shaped gabions are required, they shall be formed by folding standard gabions.
Types and Sizes b)
Gabion basket box and mattress shall be of acceptable standards and be of the types and sizes indicated
in the table below:
Table 3‐1: Gabion basket requirements
Classification Mesh type
Mesh opening
Mesh wire,
mm
Selvedge
wire , mm
Lacing (binding)
wire , mm
Basket size
(LBH), m
Tolerance in basket size
Mattress 6 x 8 64 mm ±10%
2.20 2.70 2.20 (3 – 6) x 2 x (0.17 ‐ 0.3)
±5% on length and width and ±25 mm on depth
Box 10 x 12 100 mm ±10%
3.00 3.90 2.40 (1.5 ‐ 4) x (1 ‐ 2) x (0.5 ‐ 1)
±5% on each dimension
Source: Own compilations
Baskets up to a thickness of 300 mm shall be classified as mattresses. Baskets greater than 300 mm thick
shall be classified as boxes.
Gabion basket assembly c)
The wire baskets shall be bound, tensioned and stitched properly to contain the rock fill and all openings
closed off to ensure that the rock particles cannot be dislodged.
Gabions shall be assembled by binding the edges together at the selvedge with binding wire. Binding
shall be firmly secured at all corners. The binding shall be in the form of continuous lacing. The wire shall
pass around the selvedge and through each mesh in turn, a double twist being used at alternate
meshes.
Wire baskets shall not be assembled in water.
Rockfill for gabion d)
Rockfill to be used in the gabion baskets shall be from the sources at the site and as approved by the
Engineer. Individual rock pieces shall be sound, hard, dense and durable.
Rockfill for gabion mattresses shall be graded in size within the range 90 to 150 mm, but never more
than two‐thirds the thickness of the mattress. Rockfill for gabion boxes shall be graded in size within the
range 150 – 250 mm. If there is insufficient larger material, 90 to 150 mm rockfill may be used in the
18 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
interior of gabion box compartments, subject to the approval of the Engineer. In this case the larger
material must be placed to at least 250 mm from exposed sides and 200 mm from diaphragms and 150
mm from the base and lid.
Filling of gabion basket e)
Stone filling of the gabion baskets shall not commence until the basket has been placed in its final
position and wired to all adjoining units. The filling shall be carried out ensuring that the stone is tightly
packed and has a minimum of voids.
Vertical bracing wires shall be provided between the top and bottom wire meshes at nominal 500 mm
centers. Each vertical bracing wire shall be pulled through the filling and securely fastened to the top
mesh. Horizontal bracing shall be provided in 1 m deep baskets at 500 mm centers placed at the 1/3 and
2/3 height and shall be fastened when the stone filling has reached the appropriate level.
Gabion baskets shall be filled to a level 25 ‐ 50mm above their tops, the last 100 mm being with small
rock sizes but still within the ranges specified in Clause d). The basket lids shall be tightly stretched over
the stone filling and securely bond with binding wire.
The top selvedge of baskets placed and filled under water are to remain above water until completion of
the works.
On completion of the stone filling, the baskets shall be completely and tightly filled, square, true to
dimensions and correct in line and level.
3.4 Backfilling
Backfilling materials and methods are generally subject to the approval of the Engineer. The approved
materials shall be placed in layers, not exceeding 500 mm in depth before compaction and shall be well
compacted as specified hereafter:
The layers of fill material shall be placed in such a manner as to maintain adequate drainage and to prevent accumulation of water.
The timing and rate of placing of fill material around or upon any completed or partially completed structure shall be arranged in such a way that no part of the works is overloaded, weakened, damaged or otherwise endangered.
Around structures the material shall be placed as to exert a uniform pressure and each layer shall be placed with a fall to prevent the accumulation of water.
Where necessary, the moisture content of the backfill has to be adjusted to an optimum either by drying out or by adding water. After such treatment the backfill shall be thoroughly mixed until the moisture content is uniform.
Placing the backfilling, due allowance for any settlement that may occur before the end of period of maintenance shall be made. Where necessary, the CO(s) shall at the end of the period of maintenance remove any excess material or make up any deficiency of backfilling to specified levels.
Should the material being placed as filling, while acceptable at the time of selection, become
unacceptable to the Engineer due to exposure to weather conditions or due to flooding or stagnant
surface water, soft or segregated during the progress of the works, the CO(s) shall at their own expense
remove such damaged, softened or segregated material and replace it with fresh approved material.
The CO(s) shall, when placing the backfilling, make due allowance for any settlement that may occur
before the end of period of maintenance. Where necessary, the CO(s) shall at the end of the period of
maintenance remove any excess material or make up any deficiency of backfilling to specified and
required levels.
Renewable Energy Guidelines Nov. 2013 19
Volume 12 Civil Works
3.4.1 Filling adjacent to completed structures
The CO(s) shall arrange the timing and rate of placing of fill material around or upon any completed or
partially completed structure in such a way that no part of the works is overloaded, weakened damaged
or endangered. The layers of fill material shall be placed in such a manner as to maintain adequate
drainage and to prevent accumulation of water. The placing of fill material around the walls of
structures shall commence only after the walls, floors and slabs have been completed and have attained
their full specific strength. Filling around the walls of structures shall not commence before successful
completion and testing of such structures. The material shall be placed with special care for insulation
and watertight paints and all other protective or conserving surfaces and as to exert a uniform pressure
around the walls of a structure and each layer shall be placed with a fall to prevent the accumulation of
water.
Special attention shall be paid to the compaction of material laid immediately adjacent to concrete walls
as to ensure that the material is well compacted. Hand operated vibrating plate compactors, vibro‐
tampers or power rammers shall be used. The compacting must be carried out in such a way as to avoid
in any case direct contact of the compacting machinery and the building. In other cases compaction may
be carried out by vibrating compactors or pneumatic tyre rollers of types approved by the PO Engineer.
3.4.2 Disposal of surplus material
The CO(s) shall make their own arrangements to dispose off all surplus backfill and unsuitable excavated
material from any part of the Work. The material shall be disposed off‐site and shall become the
property of the CO(s) who will be entirely responsible for its removal from the site and its ultimate
disposal.
The CO(s) shall clean the site and the surrounding ground immediately after completion of works and
leave the construction site clean and tidy.
3.4.3 Backfilling sundries
Backfilling under paved areas
When excavation is made in highways, roads, sidewalks or any other paved area, the trench shall be
backfilled and thoroughly compacted up to the bottom of the sub‐base of the surrounding pavement.
The remaining top of the trench shall be filled with graded aggregates up to the top of the base of the
pavement. The further reinstatement of surfaces shall comply with the existing pavements.
Backfilling around manholes
Backfilling around manholes and material used for it shall meet the Specifications set out for the
backfilling of adjacent trenches. In roads with a width over 3 m, the material around manholes shall be
selected and compacted to meet the requirements of base and sub‐base.
Backfilling in agricultural land
In agricultural land, backfilling to surface has to be applied, whereby the top 30 cm of the trench shall be
filled with the agricultural top soil originally found before excavation.
20 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
3.5 Embankments
The term "embankment" includes the construction of embankments around structures, hard or other
filling, embankments for roadwork and the like. Backfilling to general excavations, the forming of soil
tips and the re‐filling of trenches are specified and included in the clauses dealing with backfill.
3.5.1 Materials for embankments
Excavated material (including material from borrow pits) used as filling shall be free from clods and
lumps and shall be approved by the Engineer. When not otherwise directed, cohesive soil shall be
placed in layers not exceeding 200 mm in compacted thickness, cohesion less soil shall be placed in
layers not exceeding 300 mm in compacted thickness. Material for hard filling shall be as specified be‐
low.
Should the material being placed as filling, while acceptable at the time of selection, become
unacceptable to the PO Engineer due to exposure to weather conditions or due to flooding or become
puddled, soft or segregated during the progress of the works, the CO(s) shall at their own expense
remove such damaged, softened or segregated material and replace it with fresh approved material.
3.5.2 Filling with hardcore (hard filling)
All filling under structures, unless indicated otherwise on approved drawings or instructed by the
Engineer, shall be constructed with hardcore obtained from sources approved by the Engineer.
Hardcore shall be hard inert material passing a 75 mm sieve and be free from clay, silt, soil and
vegetable matter and shall not deteriorate in the presence of water. Hardcore shall be placed in layers
not exceeding 150 mm thickness after consolidation and each layer shall be compacted by mechanical
means. The final surface of hardcore shall be blinded with fine crushed stone and thoroughly
compacted.
3.5.3 Reinstatement and maintenance
3.5.3.1 Reinstatement of paved surfaces
The CO(s) shall restore all pavements or other surface structures removed or disturbed as a part of the
work to a condition suitable and satisfactory to the PO Engineer. No pavement shall be restored unless
and until, in the opinion of the Engineer, the condition for backfill is given in such a way as to properly
support the pavement.
The reinstatement of road surfaces and pavements will be commenced upon approval of refilling by the
PO Engineer and shall be done, if not otherwise stated, as follows:
The top 30 cm of the excavation (below the top of the base) shall be filled with graded aggregate, watered, placed in layers of 15 cm thickness and compacted to not less than 95% Proctor density
The surface shall be restored in accordance with the existing pavement and/or the direction of the PO Engineer.
3.5.3.2 Reinstatement of unpaved surfaces
Gravel roads and unpaved roads shall be reinstated to their original condition. If the original road
construction cannot clearly be applied, then 100 mm approved large gravel and 300 mm well graded
gravel compacted to 95% of maximum density shall be provided.
Renewable Energy Guidelines Nov. 2013 21
Volume 12 Civil Works
3.5.3.3 Surface reinstatement in agricultural fields
After the CO(s) has refilled excavations in fields and grass verges in the manner and to the level
specified, they shall replace all topsoil previously removed and it shall be evenly distributed and leveled
over the full extent of the stripped area. Such of the working areas occupied by the CO(s) which were
originally grassed shall be sown with grass seed of equivalent quality and maintained until the new grass
is properly established. Other areas not originally down to grass shall be dressed with suitable fertilizers
harrowed in so as to restore the original level of fertility.
3.5.3.4 Reinstatement of existing services
Where excavation is carried out close to or across the line of sewers, pipes, cables or other Services,
whether Underground or overhead, the CO(s) shall, where necessary, provide at their own cost
temporary supports or slings and where such Services are temporarily disturbed, they shall be replaced.
3.5.3.5 Reinstatement of hedges, fences and walls
Where excavation disturbs features such as hedges, fences and walls, the CO(s) shall, as a temporary
measure, provide temporary fencing for any such parts of such barriers.
After excavation has been reinstated, the CO(s) shall carry out such work as approved by the PO
Engineer for permanent restoration of such barriers.
In case of hedges, the section removed shall be replaced by saplings of the appropriate species and on
both sides by providing an adequate post and barbed wire fence. During the period of maintenance all
hedges replanted in the above manner shall be inspected and any dead sapling replaced by the CO(s).
3.5.3.6 Maintenance of backfilled surfaces
The CO(s) shall maintain the reinstated surfaces and ensure that the surfaces after backfilling are kept in
satisfactory condition during the period of maintenance. The reinstatement of any settlement shall be
carried out forthwith upon notification of the CO(s).
The reinstatement of the backfilled surface shall be done at the CO’s own expense and include (1) the
re‐excavation of the top surface, base and sub‐base, (2) compacting the backfill in the trench, (3)
backfilling the base and sub‐base with graded aggregate and (4) reinstatement of the surface according
to surface conditions met before.
3.5.4 Topsoil for re‐use
Topsoil shall be stripped from the site where the works are being constructed, where site vehicles travel,
where bulk materials are stored or as otherwise directed by the Engineer or provided in the TOP or in
accordance with the project design. It shall be stockpiled on the site not more than 1.5 m high and shall
not be traversed by any plant.
The stock‐piles of topsoil shall be grasses and kept free of weeds by treatment with a foliar acting
herbicide.
Topsoil stripped from pipeline/access easements shall not be transported out of the field from which it
was taken without permission of the Engineer.
22 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
3.5.5 Trees
Any damage to the canopy of trees of girth greater than 900 mm shall be treated at the CO's expense by
an approved tree surgeon as promptly as possible after the damage occurring or on any instruction from
the PO Engineer.
Replacement trees and hedges shall be planted in the appropriate season and shall be replaced at the
CO's expense if they fail or are damaged as a result of the CO's activities
3.6 Testing of earth works
The CO(s) shall furnish all equipment and materials necessary for collecting samples and carry out field
laboratory tests on materials for earthworks. Laboratory equipment shall be housed in a suitable
building on site, which shall also incorporate space for the storage of field test equipment.
3.6.1 Main tests and standards
The CO(s) shall carry out all tests in accordance with ZTVE‐STB 94 or equivalent international standards.
For the various tests the following DIN standards or equivalent shall be applied:
DIN 18121 MoistureTest
DIN 18122 Consistency Test
DIN 18123 Grading Tests
DIN 18124 Density Test (solid volume without voids)
DIN 18125 Density Test for Soils (including voids)
DIN 18127 ProctorTest
DIN 18134 LoadingTest
3.6.2 Compaction of soils
The CO(s) shall carry out the compaction to attain not less than the specified percentage of the
maximum dry density and control soil compaction during backfilling and filling Operation. Where the
sub‐grade or layers of soil material require being moisture conditioned before compaction, the CO(s)
shall uniformly apply water to the sub‐grade or layer of soil to attain the Optimum moisture content
required. The application of water shall be carried out in a manner to prevent free water appearing on
surface during compaction operations. The CO(s) shall dry soil material that is too wet for compaction to
the specified densities.
3.6.3 Testing of compaction
The CO(s) shall inspect, perform and report all testing and retesting as to ensure that the works conform
to the specified requirements. In order to test the degree of compaction, the CO(s) shall carry out field
density tests in accordance to DIN 18127. For each compacted backfill the required number of field
density tests to ensure compliance with specification shall not be less than three passing tests for each
500 square meters of filled and compacted area.
If the sub‐grade, backfill and fill layers have been placed and compacted to densities below the specified
limits, the CO(s) shall provide additional compaction and testing until satisfactory results are attained or
remove certain sections of the work and reconstruct them according to the Specifications at his own
expense.
Renewable Energy Guidelines Nov. 2013 23
Volume 12 Civil Works
All holes made for the purpose of tests shall be restored by the CO(s) to conform to the characteristics
of the adjacent layers. This work shall be conducted at the CO's expense.
24 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
The compaction required for various fills shall be as follows:
Item of works
Materials prescribed
% of maximum density
Backfill for over‐excavation
Formation and bedding layers
Granular material
Fine granular material
100%
95%
Crushed stone supporting layers Crusher runs 95%
Final backfill under roads, under concrete structures
Fine granular material 100 %
Backfill in general Fine granular material Sandy material
Clayey material
98%
95%
93%
Backfill below structures Fine granular material 100%
3.7 Geotextiles
3.7.1 Quality and standards
Geotextiles shall conform to the requirements of EN 13253, EN ISO 10319. Tensile strength shall be > 12
kN/m.
3.7.2 Storage
Before use, the geotextile shall be stored in a clean, dry location out of direct sunlight, not subject to
extremes of either hot or cold temperatures, and with the manufacturer's protective cover undisturbed.
3.7.3 Surface preparation
The surface on which the geotextile is to be placed shall be graded and be smooth and free of loose rock
and clods, holes, depressions, projections, muddy conditions, and standing or flowing water.
3.7.4 Placement
Before the geotextile is placed, the PO Engineer shall inspect the soil surface. The geotextile shall be
placed on the approved prepared surface. It shall be unrolled along the placement area and loosely laid,
without stretching, in such a manner that it conforms to the surface irregularities when material or
gabions are placed on or against it. The geotextile may be folded and overlapped to permit proper
placement. The geotextile shall be joined by overlapping a minimum of 0.5 m (unless otherwise
specified) and secured against the underlying foundation material. Securing pins, approved and
provided by the geotextile manufacturer, shall be placed along the edge of the panel or roll material to
adequately hold it in place during installation. Pins shall be steel or fiberglass formed as a U, L, or T
shape or contain "ears" to prevent total penetration through the geotextile. Steel washers shall be
provided on all but the U‐shaped pins. The upstream or upslope geotextile shall overlap the abutting
downslope geotextile. At vertical laps, securing pins shall be inserted through the bottom layers along a
line through approximately the mid‐point of the overlap. At horizontal laps and across slope labs,
securing shall be inserted through the bottom layer only. Securing pins shall be placed along a line 5 cm
in from the edge of the placed geotextile at intervals not to exceed 30 cm unless otherwise specified.
Renewable Energy Guidelines Nov. 2013 25
Volume 12 Civil Works
Additional pins shall be installed as necessary and where appropriate to prevent any undue slippage or
movement of the geotextile. The use of securing pins will be held to the minimum necessary. Pins are to
remain in place unless otherwise specified.
Should the geotextile be torn or punctured, or the overlaps or sewn joint disturbed, as evidenced by
visible geotextile damage, subgrade pumping, intrusion, or grade distortion, the backfill around the
damaged or displaced area shall be removed and restored to the original approved condition. The repair
shall consist of a patch of the same type of geotextile being used and overlaying the existing geotextile.
When the geotextile seams are required to be sewn, the overlay patch shall extend a minimum of 30 cm
beyond the edge of any damaged area and joined by sewing as required for the original geotextile
except that the sewing shall be a minimum of 15 cm from the edge of the damaged geotextile.
Geotextile panels joined by overlap shall have the patch extend a minimum of 50 cm from the edge of
any damaged area.
3.7.5 Measurement
The quantity of geotextile for each type placed within the specified limits is determined by
measurements of the covered surfaces only, disregarding that required for anchorage, seams, and
overlaps.
3.8 Geomembranes
3.8.1 Quality and standards
Geomembranes shall be from high density Polyethylene, with thickness of 1 mm, and conform to the
requirements of EN 13361, EN 13362, 13967.
3.8.2 Storage
Before use, the geomembrane shall be stored in a clean, dry location out of direct sunlight, not subject
to extremes of either hot or cold temperatures, and with the manufacturer's protective cover
undisturbed.
3.8.3 Surface preparation
The surface on which the geomembrane is to be placed shall be graded and be smooth and free of loose
rock and clods, holes, depressions, projections, muddy conditions, and standing or flowing water.
3.8.4 Placement
The geomembrane shall not be placed until it can be welded and protected with the specified covering
within 48 hours or protected from exposure to ultraviolet light. In no case shall material be dropped on
uncovered geomembrane from a height of more than 1 m. Before the geomembrane is placed, the soil
surface shall be inspected by the PO Engineer. The geomembrane shall be placed on the approved
prepared surface. It shall be unrolled along the placement area and loosely laid, without stretching, in
such a manner that it conforms to the surface irregularities when material or gabions are placed on or
against it. The geomembrane may be folded and overlapped to permit proper placement. The
geomembrane shall be joined by overlapping a minimum of 10 cm (unless otherwise specified). The
upstream or upslope geomembrane shall overlap the abutting downslope geomembrane. Membranes
shall be joined by heat (wedge welding) according to the instructions of the manufacturer.
26 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
Should the geomembrane be torn or punctured, or the overlaps, as evidenced by visible geomembrane
damage, subgrade pumping, intrusion, or grade distortion, the backfill around the damaged or displaced
area shall be removed and restored to the original approved condition. The repair shall consist of a
patch of the same type of geomembrane being used and overlaying the existing geomembrane. When
the geomembrane welding seams are required to be repaired the overlay patch shall extend a minimum
of 30 cm beyond the edge of any damaged area and joined by welding as required for the original
geomembrane except that the welding shall be a minimum of 15 cm from the edge of the damaged
geomembrane. Geomembrane panels joined by overlap shall have the patch extend a minimum of
50 cm from the edge of any damaged area.
3.8.5 Measurement
The quantity of geomembrane for each type placed within the specified limits is determined by
measurements of the covered surfaces only, disregarding that required for anchorage, seams, and
overlaps.
3.8.6 Testing
All welding seems shall be controlled according to DIN 18195, part 3. All welding seams shall be
controlled whether they a mechanically linked. Additionally 10% of all weldding seems shall be tested by
the vacuum method.
3.9 Drainage
All Temporary and Permanent works shall be protected from surface and ground waters by appropriate
drainage systems.
Piped drainage systems shall be made from PVC pipes, laid in appropriate filter beds. The minimum
diameter of drain pipes shall be DN 300.
Renewable Energy Guidelines Nov. 2013 27
Volume 12 Civil Works
4 Concrete works
4.1 General
4.1.1 Scope
Concrete Works as specified hereunder shall include the supply of materials, mixing of concrete,
formwork, reinforcement, placing, compaction and curing of concrete and site clearance after
completion of works.
These specifications shall apply for in‐situ concrete as well as for pre‐cast concrete elements
The bid prices entered in the Bill of Quantities shall fully include the value of works described under the
several items and shall cover the cost of all labor, subsidence, travelling, materials, temporary works,
yards and stockpiles, sampling and testing and any other expenses whatsoever together with all risks,
liabilities and obligations set forth or implied in the Contract Documents.
4.1.2 Concrete appearance
Concrete for every part of the Works shall be a homogeneous structure which, when hardened, will
have the required strength, durability and appearance. Form‐work, mixes and workmanship shall be
such that concrete surfaces, when exposed, will require no finishing.
When concrete surfaces are stripped, the concrete when viewed in good light from 3 meters away shall
have undamaged appearance, and at 6 meters shall show no visible defects.
4.1.3 Standards and rules
The CO(s) shall carry out the works described in this Section in accordance with the appropriate DIN
Standards or equivalent local or international standards. The main standards are:
DIN EN 206 Concrete ‐ specification, properties, production and conformity
DIN 1045‐1 Concrete ‐ specification, properties, production and conformity Design
DIN 1045‐2 Concrete specification, properties, production and conformity application rules
DIN 1045‐3 Concrete specification, properties, production and conformity execution of structures
DIN 1045‐4 Concrete specification, properties, production and conformity execution of pre‐fabricated structures
DIN 1048 Quality tests of concrete
DIN 1084 Quality control of concrete
DIN 1164 Cement
DIN 4226 Concrete aggregates
DIN 488 Reinforcing steel.
28 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
4.1.4 Classes of concrete (DIN 1045‐2)
The classes of Concrete to be used in the works are the following:
Table 4‐1: Classes of concrete
Class of concrete:
Cube strength, 28 days after mixing
Used for
C 8/10 100 kg/cm2 plain concrete only for fill in trenches, for blinding and for screed
C 12/15 150 kg/cm² plain concrete only for fill in trenches, for blinding and for screed and for plain and reinforced concrete for screed and encasements
C 20/25 250 kg/cm² reinforced concrete in civil structures
C 30/37 350 kg/cm² watertight concrete, thrust blocks and where especially directed by the Engineer. C 35/45 450 kg/cm²
Salt and Sulphate‐resistance: Cement used in the works for structural parts underground or in contact with water shall be seawater and sulphate‐resisting Portland cement according to DIN 4030.
Source: Own compilations
4.1.5 Organization of concrete production
After the commencement of the TOP, the CO(s) shall submit for approval of the PO Engineer a method
Statement detailing his proposal for the organization of concreting activities at the site.
The method Statement shall include:
plant proposed and layout of the production facility; a)
proposed method of organization of the production facility; b)
quality control procedures for concrete and concrete production; c)
method of transport including heat protection and placing of concrete; d)
striking times for formwork and procedure for temporary support of beams and slabs; e)
curing of concrete and ways to assure an optimum curing. f)
4.1.6 Test certificates
Unless otherwise directed by the PO Engineer, the CO(s) shall supply and submit to the Engineer:
manufacturer's test sheets with each consignment of cement and admixtures certifying the a)compliance with the relevant standards;
certification of the calibration of weighing and dispensing equipment on the batch mixing plant; b)
the certified test results for all tests carried out on aggregates, water, fresh and hardened concrete. c)
In case of doubts, new tests shall be executed upon the Engineer's direction at the CO's expense.
Renewable Energy Guidelines Nov. 2013 29
Volume 12 Civil Works
4.1.7 Aggregate samples
Before work on trial mixes is commenced, the CO(s) shall submit for approval 50 kg samples of each
aggregate which he proposes to use. The source of each aggregate shall be clearly marked on the
Container of each sample. At the same time certified test results demonstrating compliance with
relevant quality Standards shall be submitted. Samples approved by the PO Engineer shall be preserved
at site for reference.
4.1.8 Record of concreting
The CO(s) shall keep accurate and up to date records of concreting showing for each day when sections
of the works were concreted:
date, time, weather and temperature; a)
results of all concrete tests including identification for which part of works the sampled material is b)representative;
number of batches produced, weight and kind of cement used, volume of concrete placed, number c)of batches wasted or rejected;
class of concrete, volume of concrete placed and number of batches used for each location. The d)laboratory where concrete test have to be carried out shall be approved by the Engineer and the PPAF and be accessible for the said parties at any time. The laboratory should preferably be placed at the site.
4.1.9 Concrete mixes
At the commencement of the works the CO(s) shall design a mix for each class of concrete which will be
required for use in the works and shall submit full details of the mix designs to the Engineer for
approval. Each mix design shall be according to the requirements of the respective specification.
4.1.10 Movement joints, construction joints and lifts
The CO(s) shall be responsible for the design and location of movement joints, which shall be of the
contraction or expansion type as appropriate. All movement joints shall be provided with a PVC water
stop and sealant. The costs for PVC water stops are deemed to be included in the rates for the concrete
works.
Reinforcing steel shall be continuous through a construction joint, and bars projecting through a joint
shall be kept clean.
The CO(s) shall submit to the PO Engineer, not later than 3 weeks before the commencement of
concreting drawings, showing his proposals for placing concrete and the position of all construction
joints which have to be located as not to impair the strength of the structure. No concreting shall start
until the PO Engineer has approved concrete placing and the position and form of construction joints.
Rebates, keys or notches shall be formed and water stops inserted as the PO Engineer may require. The
position of construction joints and the size of formwork panels shall be so coordinated that where
possible the line of any construction joint coincides with the line of a formwork joint and that in any
case all construction joint lines and form‐work joint lines appear as a regular and uniform series. For all
exposed horizontal joints and purposely inclined joints, a uniform joint shall be formed to give a straight
and neat joint line. At contraction joints a sealant shall be set in a caulking groove formed in the con‐
crete. Expansion joints shall be provided with joint filler. Visible horizontal construction joints shall be
placed against a timber strip set in the shuttering to ensure a straight line.
30 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
Kickers for walls and columns shall always be used. Kickers shall be at least 70 mm high and shall be
incorporated with the previous concrete.
Expansion joints in structures shall be spaced such that no movement of the block separated by the joint
of more than 10 mm is to be expected.
4.2 Materials
4.2.1 Cement
All cement used on the Work shall be Standard brand Portland cement from a single approved source
conforming to the requirements of Portland cement class CEM III B 32.5 NWS in accordance to DIN
1164. Cement used in the works for structural parts underground or in contact with water shall be salt
and sulphate‐resisting Portland cement. The source of cement shall not be changed without prior
approval of the Engineer.
Cement has to be delivered to the site of works in the original sealed and branded bags. No cement shall
be used which has been manufactured 6 months prior to its proposed use on site or which has been in
storage for more than 3 months.
The CO(s) shall provide from each consignment of cement delivered to the site such samples as the PO
Engineer may require for testing. Any cement which contains, in the opinion of the PO Engineer, air set
or hardened lumps, re‐powdered air‐set material, foreign matter of contamination or what is
unsatisfactory for any reason whatsoever shall be rejected and the CO(s) shall promptly remove any
such cement from the site. Cement, which has been stored on site for more than 40 days shall not be
used in the works, unless it is retested and it complies with the relevant Standard.
4.2.1.1 Storage of cement
Immediately upon arrival on site, the cement shall be stored in silos or in dry, weather tight and
properly ventilated structures with adequate provisions to prevent absorption of moisture. All storage
facilities shall be subject to the approval by the PO Engineer and shall be such as to permit easy access
for inspection and identification. Each consignment of cement shall be kept separately and the CO(s)
shall use the consignments in the order in which they are received.
4.2.2 Aggregates
Aggregates shall be hard, durable and clean and shall not contain deleterious material in such form or
quantity as to adversely affect the strength of concrete. The aggregates shall be obtained from an
approved source, shall be washed clean and shall conform to the requirements of DIN 1045 and DIN
1084.
The portions of fine and coarse aggregates to be used for the preparation of each class of concrete shall
be approved by the Engineer. For this purpose samples of aggregate proposed by the CO(s) for use in
the Works shall be submitted to the PO Engineer for testing. The Engineer will carry out all tests at the
CO's expense. Sampling and testing shall be carried out in accordance with the requirements of the
appropriate clause of DIN 4226.
The aggregates to be supplied shall not give rise to any alkaline reaction with the cement, weather silica
or carbonate. In addition, the soluble Chloride and sulphate content of the aggregates shall be such that
the concrete mix as a whole complies with the specified limits of the salt content. Tests for Chlorides
Renewable Energy Guidelines Nov. 2013 31
Volume 12 Civil Works
and for potential alkaline reaction shall be carried out when required by the PO Engineer at the CO's
expense.
4.2.2.1 Storage of aggregates
The CO(s) shall provide storage facilities for aggregates, which have to be made that:
each normal size of coarse and fine aggregates shall be kept separate all the times; a)
contamination of aggregates by the ground or other foreign matter shall be prevented effectively at b)all times;
each heap of aggregate shall drain freely; c)
aggregates are kept as cool as possible by shading and provision of water sprinkling if required. d)
The CO(s) shall ensure that graded coarse aggregate is not segregated during tipping, storing and
removal from storage. Fine aggregate shall not be used unless, in the opinion of the PO Engineer, it is
conditioned to acceptable and uniform moisture content. If necessary to meet this requirement, the
CO(s) shall protect the heaps against weather and condition fine aggregate in accordance to re‐
quirements.
4.2.3 Water
Water for washing aggregates and for mixing of concrete shall be in accordance with DIN 1045 and DIN
4030 and shall be clean and free from objectionable quantities of organic matter, alkali, salts and other
impurities. The water shall enter the mixer at the lowest possible temperature and shall not exceed
30°C. During the execution of works the CO(s) shall ensure that sufficient quantities of water for
production and curing of concrete are available on site at all times.
4.2.4 Admixtures
The use of admixtures is to be avoided whenever possible. At the request of the CO(s) or the PO
Engineer, but in either case at the expense of the CO(s), an admixture may be added to the concrete in
Order to control the set, to effect water reduction and to increase workability. Such admixture shall not
contain calcium chloride and it shall be used in accordance to the manufacturer's instructions. Ad‐
mixtures shall not be used unless the PO Engineer has given his approval.
4.3 Concrete
4.3.1 Proportioning of concrete materials
Concrete shall be composed of cement, aggregates, water and, when unavoidable, of admixtures. These
materials shall be of the qualities specified and their proportioning shall be determined in accordance
with all requirements imposed by DIN 1045‐2 and be subject to the approval of the PO Engineer.
In general, the mix shall be designed to produce a concrete capable to be placed so as to obtain
maximum density and strength and smoothness to the surface. The proportions shall be changed
whenever necessary or desirable in the opinion of the PO Engineer.
4.3.2 Water‐cement ratio and compressive strength
The minimum compressive strength and cement content shall be not less than required in the
appropriate DIN Standard. If necessary to obtain the required strength, the Engineer may order the
32 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
cement content of any class to be increased over the quantity specified in the Standard. Such increased
quantities of cement, if so ordered, shall be furnished by the CO(s) at no additional cost to the PO and
PPAF. The maximum water‐cement ratio shall be less than 55 l of water per 100 kg of cement.
4.3.3 Limits of salt contents
All concrete mixes shall contain less than 0.6% total Chlorides (as Chloride ions) and less than 4.0% total
acid soluble sulphate (as sulphite ions). Tests shall be carried out in accordance with the appropriate DIN
Standard.
4.3.4 Consistency
The quantity of water added to a batch of concrete shall be in accordance with DIN 1045‐2, just
sufficient to produce a concrete which, in the judgment of the PO Engineer, can be placed properly
without segregation and which can be compacted by Vibration to give the desired density,
impermeability and smoothness of surface.
The quantity of water shall be changed as necessary, with variations in the nature or moisture content
of the aggregates, to maintain uniform production of a desired consistency. The consistency of the
concrete shall be determined in accordance with DIN 1048.
4.3.5 Mix design
The CO(s) shall submit to an independent laboratory, approved by the PO Engineer, samples of coarse
and fine aggregates and cement proposed to be used in the work. From analysis and test of samples
furnished, the laboratory shall design a concrete mix to meet the requirements for each class of
concrete required for use in the works. The laboratory shall prepare 2 test cylinders of each design mix
from the samples furnished and test them after 7 and 28 days, respectively. Three copies of the test
results shall be submitted to the Engineer for approval. All cost for furnishing samples, mix design and
testing shall be borne by the CO(s).
4.3.6 Trial mixes
As soon as the mix designs are approved by the PO Engineer, 3 batches of concrete for each grade shall
be made on site under full scale production conditions using the same means of the same plant the
CO(s) proposes to use in the works.
The portions of cement, aggregates and water shall be carefully determined by weight in accordance to
the approved mix design and sieve analyses shall be made in accordance with DIN 4226 of fine and
coarse aggregate used. In accordance with DIN 1048 three test cubes from each of the three batches
shall be made by the CO(s) in the presence of the PO Engineer from each trial mix. The cylinders shall be
made, cured, stored and tested with the method described in DIN 1048.
If the average value of the compressive strength of the nine cylinders taken from any trial mix is less
than the target mean strength or any individual cylinder test result falls below 85% of the target mean
strength, the CO(s) shall redesign the mix and make a further trial mix.
4.3.7 Mixing of concrete
All concrete prepared on site shall be mixed in accordance with DIN 1045 with batch mixers in
accordance with DIN 459. The mixing of each batch shall continue not less than 1.5 minutes after all
Renewable Energy Guidelines Nov. 2013 33
Volume 12 Civil Works
materials including water are in the mixer. Hardened concrete or mortar shall not be permitted to
accumulate on the inner surfaces of the mixer. Re‐tempering will not be permitted.
4.3.8 Ready‐mixed concrete
Ready mixed concrete shall not be used in any part of the works without the written approval of the PO
Engineer, which, when given, may be withdrawn at any time.
If ready‐mixed concrete is accepted, the CO(s) shall certify the PO Engineer that the ready‐mixed
concrete complies with the Specifications in all respects, and that the manufacturing and delivery
resources of the proposed supplier as well as traffic conditions are adequate to ensure proper and
timely completion of each concreting Operation.
4.3.9 Non‐shrinking grout
Unless otherwise specified, all non‐shrinking grouting specified on the drawings or where designated by
the PO Engineer shall have a compressive strength of not less than 6.0 MPa at 28 days. Mixing
proportions and instruction for use shall be followed in strict compliance with the manufacturer's
direction.
Grouting materials that will be in contact with water shall be of non‐metallic and non‐toxic type.
The CO(s) shall submit technical specifications of grouting materials to the PO Engineer for approval.
4.4 Reinforcement
4.4.1 Submissions and approvals
The following submissions are required by this Specification:
manufacturer's test certificates for each delivery of reinforcing steel, showing the country of origin a)and tests;
manufacturer's data on accessories; b)
all reinforcement drawings and bending schedules shall be prepared by the PO. before concrete is c)placed against any formwork, the reinforcement shall be inspected by the CO(s) and offered for inspection and approval by the PO Engineer. In no case concreting shall be commenced prior to the inspection of the reinforcement and the formwork by the PO Engineer and his written approval to proceed with concreting.
4.4.2 Steel reinforcement
Steel reinforcement bars shall be hot rolled untreated bars conforming to the requirements of DIN 488.
If not specified otherwise, only ribbed bars B St 220/340, B St 420/500 or B St 500/550 shall be used.
Steel reinforcement fabric shall be welded fabric conforming to the requirements of DIN 488. The steel
fabric shall be type B St 500/550 GK or B St 500/550 RK.
4.4.3 Accessories
The CO(s) shall supply all accessories such as reinforcing steel supports, hold‐downs, spreaders, hangers,
tie wire and all other incidentals necessary to complete an acceptable Installation of all concrete
reinforcement.
34 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
All accessories shall be of steel with the exception of spacers to maintain concrete cover. If not
otherwise directed by the PO Engineer, the concrete spacers shall be in the form of a truncated cone or
pyramid and shall be used with the larger face towards reinforcing steel.
4.4.4 Cutting and bending of reinforcement
Bars shall be cut and bent in accordance with the provisions of DIN 1045. All bending shall be done cold
with an approved bending machine. Cut and bent bars shall be bundled and labelled for identification
until they are incorporated into the work. Re‐bending or straightening of bars will not be permitted.
4.4.5 Storage of bars and fabric
The CO(s) shall Stack separately and label the various type of reinforcement for identification. Steel
reinforcement shall be kept clean and free from pitting.
Loose rust, mill scale, oil, grease, earth paint or any other material impairing the bond between the
concrete and the reinforcement has to be removed before steel fixing. Reinforcing steel shall be stored
under cover on wooden support, elevated from the ground surface.
4.4.5.1 Fixing of reinforcement
All reinforcement shall be securely and accurately fixed in positions shown on the approved drawings
using approved spacer blocks and chairs. The CO(s) shall ensure that all reinforcement is maintained in
position at all times, particular care being taken during placing of concrete. Reinforcement in slabs shall
be maintained in position by means of chairs at 90 cm centers maximum. Reinforcement in walls with
two layers of reinforcement shall be maintained in position by means of 6 mm U‐or Z‐shaped spacers at
180 cm centers maximum.
No part of the reinforcement shall be used to support formwork, assess ways, working platforms or the
placing of equipment. Welding of reinforcement is subject to the permission of the PO Engineer.
4.4.6 Concrete cover
Except as otherwise shown in approved drawings or stated elsewhere in the contract, reinforcement
shall be installed with clearance coverage as follows:
all surfaces in contact with water or placed against 5.0 cm
soil bottom side of slabs over water and beams and columns not exposed to soil or water
4.0 cm
surfaces exposed to air and all interior surfaces in buildings: 3.0 cm
4.4.7 Tolerances
Tolerances in placing reinforcement shall be:
for members 60 cm or less in depth +/‐ 0.5 cm
for members more than 60 cm in depth +/‐1.5 cm
Renewable Energy Guidelines Nov. 2013 35
Volume 12 Civil Works
4.4.8 Approval by PO engineer
In no case shall any reinforcing steel be covered by concrete until the amount and position of the
reinforcement have been checked by the PO Engineer and his permission given in writing to proceed
with the concreting.
4.5 Formwork
Formwork shall be constructed of timber, sheet metal or other approved material. The CO(s) shall
furnish all struts, braces and ties to withstand the placing and vibrating of concrete. Except, when
otherwise expressly approved by the PO Engineer, all material brought on the site as forms, struts or
braces shall be new material.
All concrete structures shall be constructed as fair finish (Class B). Concrete works at the powerhouse
shall be done as smooth finish (Class A).
For each class of finish the CO(s) shall present sample panels to the satisfaction of the Engineer. If the
sample panels do not meet the requirements, in the opinion of the Engineer, the CO(s) shall present
new samples. Sample panels shall not be less than 2 m² in area.
4.5.1 Submissions
The following submissions are required:
design and shop drawings for formwork;
layout of panels.
Before concrete is placed against any formwork, the formwork shall be inspected by the CO(s) and
offered for inspection and approval by the PO Engineer. In no case concreting shall be commenced prior
to the inspection of the formwork by the PO Engineer and his written approval to proceed with
concreting.
4.5.2 Requirements
4.5.2.1 Form ties
Form ties for use in water‐retaining structures shall incorporate a diaphragm not less than 50 mm
diameter welded to the mid point of the tie, designed to prevent water passing along the tie.
Form ties with integral water stops shall be provided in a cork or other suitable means for forming a
conical hole to ensure that the form tie may be broken off back of the face of the concrete. The
maximum diameter of removable cones for rod ties, or of other removable form tie fasteners having a
circular cross section, shall not exceed 40 mm and all such fasteners shall be such as to leave holes of
regular shape for reaming. Holes left by the removal of fasteners having from the end of snap‐ties or
form ties shall be reamed with suitable toothed reamers so as to leave the surfaces of the holes clean
and rough before being filled with mortar. Wire ties for holding forms will not be permitted.
No form‐tying device or part thereof, other than metal, shall be left embedded in the concrete, not shall
any tie be removed in such manner as to leave a hole extending through the interior of the concrete
member. The use of snap‐ties which cause spalling of the concrete upon form stripping or tie removal
will not be permitted. If steel panel forms are used, rubber grommets shall be provided where the ties
pass through the form in order to prevent loss of cement paste.
36 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
Where metal rods extending through the concrete are used to support or to strengthen forms, the rods
shall remain embedded and shall terminate not less than 50 mm back from the surface in the case of
reinforced concrete and 150 mm in the case of un‐reinforced concrete.
4.5.2.2 Number of forms
A sufficient number of forms of each kind shall be provided to permit the required rate of progress to be
maintained. Whenever, in the opinion of the PO Engineer, additional forms are necessary to maintain
the progress of works, such additional forms shall be provided by the CO(s) at his own expense. The
design of concrete forms and shoring shall comply with applicable standards.
4.5.2.3 Design of formwork
The CO(s) shall be responsible for the adequacy and safety of formwork and the compliance of the
formwork with the Specification:
All forms shall be true in every respect to the required shape and size, shall conform to the a)established alignment and grade and shall be of sufficient strength and rigidity to maintain their position and shape under the loads and operations incident to placing and vibrating the concrete.
Concrete construction joints will not be permitted at locations other than those shown on approved b)shop drawings. When a second lift is placed on hardened concrete, special precautions shall be taken in the location and tightening of ties at the top of the old lift and the bottom of the new to prevent any unsatisfactory effect whatsoever on the concrete.
All exposed arises and exterior corners shall be chamfered (30x30 mm), unless specifically shown c)otherwise in the drawings or directed by the PO Engineer.
All vertical surfaces of concrete members shall be formed, unless placement of the concrete against d)the ground is called for and explicitly authorized by the PO Engineer. Permission for placing concrete against trimmed ground in lieu of forms will be granted only for members of limited height and where the properties of the ground allow for it.
Top formwork shall be used on any inclined concrete surface steeper than 15° to the horizontal. e)
4.5.2.4 Formed surfaces
Finishes to formed surfaces are classified as follows:
Class A: Surfaces exposed to view where good appearance is of special importance. To achieve the
required finish, the formwork shall be faced with plywood or equivalent material in large sheets.
Wherever possible, joints shall be arranged to coincide with architectural features. All joints between
panels shall be vertical and horizontal, unless otherwise directed. Un‐faced wrought boarding or
Standard steel panels will not be permitted for class A finish.
Class B: Finish for surfaces which are exposed to view but where the highest Standard of finish is not
required. Forms shall be faced with wrought boards with square edges arranged in a uniform pattern or,
alternatively, with plywood or metal panels, which are free from defects disturbing the general
appearance,
Class C: Finish for surfaces, which are not exposed to view. The formwork shall consist of boards, sheet
metal or any other material, which will prevent the loss of materials during placing and vibrating of
concrete.
Where the class of finish is not specified, the concrete shall be finished in accordance to the
requirements of class B surfaces.
Renewable Energy Guidelines Nov. 2013 37
Volume 12 Civil Works
4.5.2.5 Mounting of formwork
All formwork shall be constructed, firmly supported, adequately strutted, braced and tied to withstand
the placing and vibrating of concrete. Formwork shall not be tied to or supported by reinforcement.
Faces of formwork in contact with concrete shall be free from adhering matter, projecting nails and the
like, split or other defects, and shall be clean and free from stagnant water, dirt, shavings, chippings or
other foreign matter. Joints shall be sufficiently water tight to prevent the escape of mortar or the
formation of fins or other blemishes on the face of the concrete.
Formwork in contact with concrete shall be treated with suitable non‐staining mould oil prior to
reinforcement and concrete placement to prevent adherence of the concrete. Care shall be taken to
prevent the oil from coming into contact with the reinforcement or with concrete at construction joints.
Surface retarding agents shall not be used unless approved by the PO Engineer. Where ties are built into
the concrete for the purpose of supporting the framework, the whole or part of any such support shall
be capable for removal in such a way that no part remains embedded nearer than 5.0 cm from the
surface. Holes left after the removal of such supports shall be neatly filled with well rammed dry‐packed
mortar.
4.5.2.6 Tolerances
The permissible tolerances in the finished faces of shuttered concrete shall, if not otherwise directed,
not exceed the following values:
Type of concrete works: Buried concrete Exposed concrete
Deviation from alignment: 50 mm 10 mm
Deviation from grades: 10 mm 10 mm
Deviation from dimensions: +10/‐5mm +10/‐5mm.
4.5.2.7 Removal of formwork
Formwork shall be designed as to permit easy removal without resorting hammering or levering against
the surface.
The period of time elapsing between the placing of the concrete and the striking of the formwork shall
be as approved by the Engineer and shall be in any case not less than the period stated in DIN 1045‐3. If
not otherwise directed, the striking times for formwork shall be as follows:
Side formwork for beams, walls, columns: 4 days
Formwork for floor slabs: 10 days
Formwork for beams, frames and long span slab: 28 days
4.6 Joints
4.6.1 Construction joints
A construction joint is defined as a joint in the concrete introduced for convenience in construction at
which special measures are taken to achieve subsequent continuity without Provision for further
relative movement.
38 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
Concrete placed to form the face of a construction joint shall have all laitance removed and the large
aggregate exposed prior to the placing of fresh concrete.
The laitance shall wherever practicable be removed when the concrete has set but not hardened by
spraying the concrete surface with water under pressure or brushing with a wire brush sufficient to
remove the outer mortar skin and expose the large aggregate without being disturbed. Where the
laitance cannot be removed due to hardening of the concrete, the whole of the concrete surface form‐
ing the joint shall be treated by high pressure water jet, sand blasting, use of a needle gun or a scaling
hammer to remove the surface laitance.
Bonding shall be required at all joints in walls, except where otherwise shown or specified.
Concrete next to water stops shall be placed in accordance with below.
4.6.1.1 Construction joint sealant
Where required, construction joints in floor slabs shall be formed with grooves, which shall be filled with
a construction joint sealant. The materials used for forming the grooves shall be left in the grooves until
just before the grooves are cleaned and filled with joint sealant. After removing the form from the
grooves, all laitance and fins shall be removed and the grooves shall be sandblasted. The grooves shall
be allowed to become thoroughly dry, after which they shall be blown out, immediately thereafter, they
shall be primed and filled with the construction joint sealant. The primer used shall be supplied by the
same manufacturer supplying the sealant. No sealant will be permitted to be used without a primer.
Care shall be used to completely fill the sealant grooves. Areas designated to receive a sealant fillet shall
be thoroughly cleaned, as outlined for the grooves, prior to application of the sealant. The sealant shall
be two‐pack polyurethane polymer designed for bounding to concrete, which is continuously
submerged in water. No material will be acceptable which has an unsatisfactory history as to bond or
durability when used in the joints of hydraulic structures. Prior to ordering the sealant material, the
CO(s) shall submit to the PO Engineer for approval sufficient data to show general compliance with the
specification requirements.
The material shall meet the following requirements:
Work life 45‐90 min. time to reach all hardness (at 25°C, 200 gr. quantity) : 20 hrs max
Tensile strength 16 kg/cm²
Ultimate elongation 400% in 5 min
Tear resistance: 120 kg per cm of thickness
Alternatively a two‐pack polysulphide may be used as a sealant.
Certified test reports from the sealant manufacturer on the actual batch of material being supplied
indicating compliance with the above requirements shall be furnished to the PO Engineer before the
sealant is used on the Job. The primer and sealant shall be placed strictly in accordance with the
recommendations of the manufacturer, taking special care to properly mix the sealant prior to
application. Before any sealant is placed, the persons carrying out the work shall be carefully instructed
as to the proper method of application. All sealant shall cure at least 7 days before the structure is filled
with water.
Renewable Energy Guidelines Nov. 2013 39
Volume 12 Civil Works
4.6.2 Water stops
Central water stops shall have 10 mm thick webs and be extruded from an Elastomer polyvinyl Chloride
compound containing the necessary plasticizers, resins, stabilizers and other materials necessary to
meet the requirements of these Specifications. No reclaimed or scrap material shall be used. The water
stop manufacturer shall furnish to the PO Engineer current test reports and a written certification that
the material to be supplied meets the following physical requirements:
40 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
Table 4‐2: Water stops requirements
Physical property, sheet material: Value
Tensile strength Min (kg/cm²) 120
Ultimate elongation Min (%) 350
Stiffness in flexure Min (kg/cm) 28
Accelerated Extraction:
Tensile strength Min (kg/cm²) 105
Ultimate elongation Min (%) 300
Finished Water Stop:
Tensile strength Min (kg/cm²) 100
Ultimate elongation Min (%) 280
Source: Own compilations
4.6.3 Splices and Joints
Prior to use of the water stop material in the field, a cross section sample of a fabricated water stop of
each size or shape to be used shall be submitted to the PO Engineer for approval. These samples shall be
fabricated so that the material and workmanship represent in all respect the fittings to be furnished
under this contract. When tested, they shall have a tensile strength across the joints equal to at least
42 kg/cm².
Field splices and joints shall be made in accordance with the water stop manufacturer's instructions
using a thermostatically controlled heating iron.
4.6.4 Flat‐steel water stops
For flat‐steel water stops the thickness shall be less than 5 mm. Adequate means shall be provided for
anchoring the water stop in concrete. In placing flat‐steel water stops in the forms, means shall be
provided to prevent them from being folded over by the concrete as it is placed. Horizontal water stops
shall be held in place with continuous supports to which the top edge of the water stop shall be tacked.
Vertical water stops shall be held in place with light wire ties at 45 cm centres, which shall be passed
through the edge of the water stop and tied to the two curtains of reinforcing steel. In placing concrete
around water stops, concrete shall be worked under the water stops by hand so as to avoid the
formation of air and rock pockets.
4.6.5 Movement joints
Movement joints for expansion and contraction shall be constructed in accordance with the details and
to the dimensions shown on the approved drawings or where otherwise ordered by the Engineer and
shall be formed of the elements specified.
The CO(s) shall pay particular attention to the effects of climatic extremes about the works on any
material which he may desire to use in any movement joints and shall submit for approval by the PO
Engineer his proposals for the proper storage handling and use of the said materials having due regard
to any recommendations in this connection made by manufacturers. Water stops shall be incorporated
into all expansion and contraction joints in units, which retain or exclude liquids. Water stops shall
Renewable Energy Guidelines Nov. 2013 41
Volume 12 Civil Works
conform to the requirements specified elsewhere. Different types of water stop material shall not be
used together in any complete installation.
Water stops shall be fabricated into the longest practical units at the supplier's works and shall be
continuous throughout the structure below highest water level. Intersections and joints shall be factory
made where possible.
Water stops shall be carefully maintained in the position and supported on accurately profiled stop
boards to create rigid conditions.
Joint filler shall be either cork/bitumen joint filler or cellular joint filler. Cork/bitumen joint filler shall be
waterproof and rot proof and shall not extrude as a result of compression. Cork joint filler shall
compress to less than 50% of its original thickness with immediate recovery to 80% or more of its
original thickness. Cellular joint filler shall be used only for joints of low horizontal loading and shall be
pre‐formed low compression joint filler made from foam rubber. Cellular joint filler shall recover to its
original thickness after each loading and unloading. The joint filler shall be fixed to the required
dimensions of the joint cross section and shall provide a firm base for the joint sealer. Where the depth
of joint between the concrete surface and the water stop does not exceed 500 mm, filler shall be placed
in single depth sections.
Sealing of movement joints shall be carried out only when adjacent concrete surfaces are perfectly dry
and as long after the concrete has been set as possible. Immediately before the application of the joint
sealer the groove protection batten shall be removed in such lengths as represent a single day’s work
for sealing the joints.
The joint grooves shall be cleaned, adequately primed and filled with approved sealer strictly in
accordance with the manufacturer's instructions and on joints of 25 mm and larger with a shape factor
of 2:1 (width to depth).
On permanently exposed areas of structures joint sealing is to be carried out with the aid of masking
tape to form neatly defined surface limits to the sealer.
4.6.5.1 Sliding planes
Sliding planes on the concrete and joint blinding layers shall consist of a bitumen sand mixture 1 to 4 by
volume spread evenly 3 mm thick over the carpet coat or of building paper either of which shall be
applied immediately before the structural floor is concreted and shall be at all times suitably protected.
Where building paper is used the concrete formation carpet shall be finished with a steel trowel to give
a smooth surface.
Sliding joints shall consist of two layers of purpose made preformed plastic membrane which when in
contact shall give a coefficient of friction of not more than 0.2 when subjected to a load of 270 kg/m2.
The lower joint bedding surface formed in concrete structures shall be steel float finished to a smooth
true surface.
42 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
4.7 Concreting
4.7.1 Preparing for concreting
For the preparation of Concreting, the following shall apply:
No concrete shall be placed until all formwork, installation of reinforcement and parts to be a)embedded and preparation of surfaces involved in the placing have been approved by the PO Engineer.
Each surface shall be free from mud and debris and be thoroughly wetted by sprinkling prior to the b)placing of any concrete.
For watertight structures all slabs, beams and walls shall be concreted in one batch. Before any c)concrete is placed, the CO(s) shall carry out an inspection to ensure that all preparations are complete, including the provisions of the necessary equipment and personnel and shall ensure that sufficient materials are available to complete the works proposed.
4.7.2 Transporting and placing
Concrete shall be transported from the mixer to its place in the works as rapidly as possible by methods,
which will prevent segregation or drying out and ensure concrete of the required workability at the time
of placing:
concrete shall not be placed when unsuitable wind and temperature conditions prevent proper placement and curing as determined by the PO Engineer;
concrete shall be placed by hoppers and chutes and, if necessary, by vertical ducts; the free fall of concrete after chutes and ducts shall in no case exceed 1.5 m;
concrete shall not be dropped through any reinforcement or into any deep form in order to avoid segregation;
concrete shall be placed and compacted before the initial set has occurred and, in any event, not later than 45 minutes from the time of mixing.
The concrete shall be placed in the presence of the PO Engineer, unless agreed otherwise with him. The
CO(s) shall notify the PO Engineer by writing 24 h prior to the placing of any concrete. The order of
placing in all parts of the work shall be subject to the approval of the PO Engineer. In order to minimize
the shrinkage, the concrete shall be placed in units as bounded by construction joints. The placing of the
units shall be done in such a way, that each unit shall have cured for at least 7 days before the
continuous units are placed, with the exception of walls which shall be placed not before the wall
footings or adjacent wall panels have cured for at least 14 days.
Whenever a run of concrete is stopped or completed, the surface of the concrete shall be levelled with a
trowel and all laitance shall be removed.
Concrete, which is, before placing, found not to be conforming to the requirements shall be rejected
and immediately removed from the site. Concrete which is not placed in accordance with the above
requirements, or which is found to be of inferior quality as determined by the PO Engineer shall be
removed and replaced by and at the expense of the CO(s).
Concrete placing will not be permitted if, in the opinion of the PO Engineer, the CO(s) does not have
proper facilities available on site for placing, curing and finishing the concrete in accordance with these
specifications.
Renewable Energy Guidelines Nov. 2013 43
Volume 12 Civil Works
4.7.3 Compaction
As concrete is placed in forms or in excavations, it shall be thoroughly settled and compacted,
throughout the entire depth of the layer which is being consolidated, into a dense, homogenous mass,
filling the form completely, thoroughly embedding the reinforcement, eliminating air and aggregate
pockets and bringing only a small amount of excess water to the surface of concrete during placing.
For compaction the CO(s) shall use power driven vibrators supplemented by hand spading and tamping,
except as otherwise approved by the PO Engineer. A sufficient number (including standby) of
appropriate sizes vibrators shall be at all times available on site.
4.7.3.1 Attendance of reinforcement worker and carpenter
During the concreting of all reinforced concrete, a competent reinforcement worker and carpenter shall
be in attendance on each concreting gang and shall ensure that the reinforcement, formwork, spacers
and embedding fittings are kept in position as works proceed.
4.7.4 Concreting in hot weather
The temperature of concrete as placed shall not exceed 30°C in order to prevent rapid drying of the
newly placed concrete. To achieve this, the CO(s) shall provide sun shades over aggregate stockpiles,
cement silos and mixing water tanks and preferably place concrete during the night hours. With the
approval of the Engineer, also the following procedures may be applied:
cooling of mixing water by chipped ice;
sprinkling of stock piles with water;
shade or wet the outside of the formwork.
The fresh concrete shall be shaded and cured as soon as the surface of fresh concrete is sufficiently
hard.
4.7.5 Concreting in cold weather
Given cold weather and frost, the concrete must be of certain minimum temperature when being
brought into place. At ambient temperatures of between +5°C and ‐3°C the temperature of concrete
used may not be lower than + 5°C.
If the content of cement is lower than 240 kg/m³, the temperature of the concrete may not be lower
than +10°C. At ambient temperatures of below ‐3°C the temperature of the concrete used must be at
least +10°C and must subsequently be kept at this temperature (+10°C) for at least 3 days. With the
approval of the PO Engineer, also the following procedures may be applied:
warm the mixing water and possibly also the aggregates; the temperature of the unset concrete may not exceed +30°C (aggregates should not be used when they are frozen);
use of heat insulating shuttering;
delayed stripping of formwork;
enclosing the building works with canvas shelters
addition of heat; during this process the water necessary to harden the concrete may not be withdrawn.
It is not allowed to add concrete to frozen concrete parts and concrete damaged by frost has to be
removed before concreting continues.
44 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
4.7.6 Curing of concrete
Concrete curing shall be carried out in compliance with DIN 1045‐3. All concrete shall be cured by
protecting the surface from the effects of sun, drying winds, rain, running water or mechanical damage
for a continuous period of at least seven days by:
keeping wooden formwork wet until it is removed;
covering the concrete surface with burlap mats and keeping them wet;
covering the surface with moist earth (not before 4h and not longer than 24 hours after concreting);
spraying the surface with water or a liquid curing compound.
4.7.7 Care and repair of concrete
The CO(s) shall protect all concrete against injury or damage from excess heat, lack of moisture,
overload or any other cause until final acceptance by the PO Engineer.
Any concrete found to be damaged, which may have been originally defective, which becomes defective
prior to the final acceptance of the completed work or which does not conform to the Specification,
shall be satisfactorily repaired or removed and replaced by the CO(s) at his own expense.
4.7.8 Failure to meet requirements
Should the strengths shown by the lest samples made and tested in accordance with the above
provisions fall below the values given in the design, the Engineer shall have the right to require the
necessary changes in mix proportions to apply to the remainder of the work. Furthermore, the Engineer
shall have the right to require additional curing on those portions of the structure represented by the
test samples, which failed. The cost of such additional curing shall be borne by the CO(s) . In the event
that such additional curing does not give the strength required, as evidenced by core and/or load tests,
the Engineer shall have the right to require strengthening or replacement of those portions of the
structure which fail to develop the required strength. The cost of all such core boring and/or load tests
and strengthening or concrete replacement required because strengths of test specimens are below
those specified, shall be entirely at the expense of the CO(s). In such cases of failure to meet strength
requirements, the CO(s) and Engineer shall confer to determine what adjustment, if any, can be made in
conformity with Afghan standards or other if it is necessary.
When the tests on control samples of concrete fall below the required strength, the Engineer will permit
check tests for strengths to be made by means of cores drilled from the structure. In case of failure of
the latter, the PO Engineer, in addition to other recourses, may require at the CO's expense, load tests
on any slabs, beams, piles, caps, walls and columns in which such concrete was used. Tests need not be
made until the concrete has aged 60 days.
4.7.9 Patching
It is the intent to require shuttering, mixtures of concrete and workmanship so that concrete surfaces,
when exposed, will require no patching. As soon as the shuttering have been stripped and the concrete
surfaces exposed, fins and other projections shall be removed; recesses left by the removal of form‐
work ties shall be filled; and surface defects, which do not impair structural strength as determined by
Engineer, shall be repaired. All exposed concrete surfaces and adjoining work stained by leakage of
concrete shall be cleaned.
Immediately after removal of shuttering, the CO(s) shall remove plugs and break off metal ties as
required herein. Holes shall be promptly filled by moistening the hole with water, followed with a
Renewable Energy Guidelines Nov. 2013 45
Volume 12 Civil Works
1.5 mm brush coat of neat cement slurry mixed to the consistency of a heavy paste. The hole shall
immediately be plugged with a 1:1.5 mixture of cement and fine aggregate slightly damp to the touch.
Grout shall be hammered into the hole until dense, and an excess of paste appears on the surface. The
surface shall be trowelled smooth with heavy pressure, avoiding burnishing. Formwork tie holes in the
exposed exterior walls and interior walls shall likewise be immediately filled except that the holes shall
be filled only to the depth shown on the Drawings. Extreme care shall be taken to ensure that the colour
of the grout used to fill these holes is the same as that of the parent concrete.
When patching or repairing exposed surfaces the same source of cement and sand as used in the parent
concrete shall be employed. The color shall be adjusted, if necessary, with the addition of proper
amounts of white cement. The surface shall be rubbed lightly with a fine carborundrum stone at an age
of 1 to 5 days, if necessary, to bring it even with the parent concrete. Care shall be exercised to avoid
damaging or staining the virgin skin of the surrounding parent concrete. The surface shall be washed
thoroughly to remove all rubbed matter.
Defective concrete and honeycombed areas, as determined by the PO Engineer, shall be chipped down
reasonably square and at least 25 mm deep to sound concrete by means of hand chisels or pneumatic
chipping hammers. Irregular voids or surface stones need not be removed if they are sound, free of
laitance, and firmly embedded in the parent concrete, subject to the Engineer's final inspection. If
honeycomb exists around reinforcement, the concrete shall be chipped to provide a clear space at least
10 mm wide all around the steel. For areas less than 38 mm deep, the patch may be made in the same
manner as described above for filling form tie holes, care being exercised to use adequately dry (non‐
trowellable) mixtures and to avoid sagging. Thicker repairs will require build‐up in successive 38 mm
layers on successive days, each layer being applied as described below.
Hydraulic structures shall be repaired by using cement mortar, non‐shrinking materials (cement base,
epoxy base etc.), or expanding grout, as determined by the PO Engineer case by case. The CO(s) shall
submit the proposed materials to be used in repairing work together with the repairing procedure to the
PO Engineer for approval prior to starting the repairing work.
4.7.10 Finish of concrete surfaces
Workmanship in formwork and concreting shall be such that concrete does not require making good, i.e.
surfaces are perfectly compacted, smooth and with no irregularities. Surfaces shall be free from fins,
bulges, ridges, offsets, honeycombing or roughness of any kind.
Except if otherwise provided, unformed top surfaces of concrete shall be brought to a uniform surface
and worked with suitable tools to a smooth wood‐float finish. Excessive floating of surfaces while the
concrete is plastic will not be permitted.
As soon as forms are removed, all exposed surfaces shall be carefully examined and any irregularities
shall be immediately rubbed or ground in a satisfactory manner in order to secure a smooth and
uniform surface. Plastering or coating of surfaces will not be permitted. No repairs shall be made until
after inspection by the Engineer and then only in strict accordance with his directions. Concrete contain‐
ing voids, holes, honeycombing or similar depressions shall be completely removed and replaced.
4.7.11 Built‐in machinery and plant
Wherever possible, pipes and other items of plant shall be installed and built into the structures as work
proceeds. Where this procedure is impossible due to programs or other requirements, holes and
openings shall be made for the later Installation of the items of plant.
46 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
Individual parts shall not be built into the concrete structures before accurate fitting of the whole
system. Where openings are made or holes are formed, these shall be of size and shape sufficient to
permit proper placing and compaction of concrete or grout. The surfaces shall be treated to produce a
bonded surface before Installation of plant.
Before building‐in commences the plant shall be adequately supported in position to prevent movement
or damage during building‐in. Concrete used for building‐in shall be of the same class as concrete of the
part of work into which the plant is built. Concrete, mortar and grout shall be carefully placed and
compacted around the plant to avoid damaging or moving the plant.
4.7.12 Puddle flanges and pipe supports
Puddle flanged fittings for building into the walls may be the single‐flanged type. Where the single‐
flanged type is used it shall be positioned so that the puddle flange is in the centre of the wall. Where
the double‐flanged type is used it shall be positioned so that the outside face of each flange is flush with
the face of the wall. Pipe supports shall be provided by the CO(s) where necessary both during and after
construction. The CO(s) shall be entirely responsible if damage is caused to pipes because of his failure
to provide adequate supports.
4.8 Pre‐cast concrete
Pre‐cast concrete units shall be obtained from an approved manufacturer or prepared by special skilled
employees and shall be true to dimension and shape, with true arises and with perfectly smooth
exposed faces free from surface blemishes, air holes, crazing or other defects, whether developed
before or after building‐in. The concrete shall comply in every respect with the provisions of the
contract whether such units are manufactured on the site or obtained from other manufacturers. All
cement, aggregate and other materials for pre‐cast concrete units with faces which are exposed
whether internally or externally shall be from the same sources throughout. Exposed surfaces of the
units shall be uniform in color and in texture. Formwork and unformed surfaces for pre‐cast concrete
units shall comply generally with the accuracy grade "C" according to DIN 18202.
4.9 Concrete for benching
Concrete benching in works structures shall consist of class C 20/25 concrete unless otherwise specified.
It shall be placed with low workability to the approximate shape required and, while still green, shall be
finished with not less than 50 mm of class C 20/25 concrete to a steel trowelled finish and to the
contours indicated on the drawings.
4.10 Pumping concrete
Where pumping of concrete is permitted to be used, no relaxation of the requirements of this
Specification will be permitted. Particular attention shall be paid to the proper grading of aggregates to
prevent bleeding and/or segregation during the pumping operations. The inclusion of water‐reducing
additives or other materials, including fly ash, to improve the flow characteristics of the concrete will
only be permitted where it can be shown that they do not adversely affect the concrete either in the
plastic phase or in the finished work.
Renewable Energy Guidelines Nov. 2013 47
Volume 12 Civil Works
4.11 Inspection and testing
4.11.1 Inspection procedures
Before any concrete is placed, the CO(s) shall carry out an inspection to ensure that all preparations are
complete, including the provisions of the necessary equipment and personnel and shall ensure that
sufficient materials are available to complete the works proposed.
After completion of this inspection, the work shall be offered for inspection by the PO Engineer and
sufficient time shall be allowed for inspection and correction of any defects. No concrete shall be placed
until the PO Engineer has inspected and approved the surfaces upon which the concrete is placed, the
formwork and the reinforcing steel.
4.11.2 Sampling and testing of aggregates
The CO(s) shall sample and carry out mechanical analysis of the fine aggregates and each normal size of
coarse aggregate in use, employing the method described in DIN 4226 at least once a week when
concreting is in progress and at such more frequent intervals as the Engineer may require.
The grading of all aggregates shall be within specified limits. Should the fraction of aggregate retained
on any sieve differ from the corresponding fraction of aggregate in the approved mix by more than 5%
of the total quantity of fine and coarse aggregate, the PO Engineer may instruct the CO(s) to alter the
relative portions of the aggregates in the mix to allow for such differences.
4.11.3 Sampling and testing of concrete
The CO(s) shall provide the equipment necessary to determine the compacting factor of freshly mixed
concrete at each place where concrete is being prepared and shall determine the compacting factor of
the freshly mixed concrete by the method described in DIN 1048 on each location where a set of test
cubes is made and not less than once a day or as the Engineer may direct.
Unless particularly specified, for each grade of concrete works test cubes shall be made whenever
required by the PO Engineer but not less frequently than one set of cubes per 100 m³ or part thereof
concreted per day.
Each set of cubes (six cubes per set) shall be made from a single sample of a concrete batch taken by
random. Each three cubes shall be tested 7 and 28 days after manufacture. When requested by the PO
Engineer, additional set of cubes shall be made for testing 3 days after manufacture. Test reports shall
be submitted to the PO Engineer in duplicate.
4.11.4 Compliance with specified requirements
The concrete shall be deemed satisfactory provided that:
the average 28 days strength determined from every group of four consecutive test cubes exceeds a)the characteristic strength by not less than 5 N/mm2 for grade C 12/15 concrete and 7,5 N/mm2 for grades more than C 12/15;
each individual test result is greater than 85% of the specified characteristic strength. b)
If one cube result fails to meet the second requirement, the result may be considered to represent only
the particular batch of concrete from which the cube was taken, provided that the average strength of
the group satisfies the first requirement.
48 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
If more than one cube in a group fails to meet the second requirement or if the average strength of any
group of four consecutive test cubes fails to meet the first requirement, then all the concrete in all the
batches represented by such cubes shall be deemed not to comply with strength requirements.
4.11.5 Non‐compliance with specified requirements
When the average strength of four consecutive test cubes fails to meet the first requirement, no further
concrete from that mix shall be placed in the work and the CO(s) shall establish the cause of the failure
and apply such remedies as are necessary. The Contractor shall demonstrate by trial mixes and test cube
results that the revised mix is in accordance with the specified requirements.
The CO(s) shall, within 24 hours of the date of testing, make proposals for agreement with the Engineer
about actions to be taken in respect of any concrete represented by the test cubes which fail to meet
either of the requirements. These proposals may include, but shall not be limited to, cutting and testing
cores.
Concrete, which ultimately does not comply with any of the requirements of the Specification shall be
broken out and replaced or otherwise dealt with as agreed by the PO Engineer at the expense of the
Contractor.
Furthermore, the PO Engineer may order additional cement to be added to the mix immediately. The
mixes used may also be changed whenever, in the opinion of the PO Engineer, such change is necessary
or desirable to secure the required workability, density, impermeability, surface finish and strength, and
the CO(s) shall not be entitled to additional compensation because of such changes.
4.12 Cutting and testing of core samples
As and where directed by the Engineer, cylindrical core samples shall be taken normal to the surface of
the hardened concrete for examination and testing. The procedure for drilling, examination,
measurement and testing shall be in accordance with DIN 1048. Prior to the preparation for testing, the
specimen shall be made available for examination by the PO Engineer. If the crushing strength of the
specimen determined in accordance to DIN 1048 is less than the characteristic strength at 28 days for
the grade requirements in other aspects, that concrete in that part of the works of which it is a sample
shall be considered not to comply with the specified requirements.
4.12.1 Water‐retaining structures
4.12.2 Watertight linings and coatings
Watertight coatings to be used by the CO(s) must be approved by the PO Engineer. The CO(s) shall
supply technical specifications, giving details of the mechanical properties, references and guarantees
for the proposed material to the PO Engineer.
Application and use of any such product shall be in strict accordance with the manufacturer's
instructions and recommendations.
The CO(s) must submit his method Statement for correctly measuring the thickness of the applied seal
to the PO Engineer for approval.
Cement plaster applied for lining and water tight coatings shall conform to group PIII as per DIN 18550.
Renewable Energy Guidelines Nov. 2013 49
Volume 12 Civil Works
4.12.3 Application of sealing resins
In the case of inadequate sealing of the work or cracking of the concrete, the faults will be corrected by
the CO(s), at his own cost, by the placing of nozzles for injection of pure acrylic resin or other suitable
material, approved by PO Engineer. The spacing of the injection nozzles shall not exceed 200 mm.
The resin shall be suitable for use in food processing and inert with respect to chlorinated water. The
agreement of the PO Engineer will be required to permit use of this product.
Nozzle Installation will be subject to the control of the Engineer.
In order to ensure proper water‐tightness, keep to the contract timetable and minimise the
consumption of water by multiple tests of watertightness, the Engineer may require the CO(s) , after
two unsatisfactory tests, to proceed with resin injection work while the water‐retaining structures are
full.
The method of application, including injection pressure, proposed by the CO(s) shall be agreed in
advance with the PO Engineer.
4.12.4 Testing of water retaining structures
4.12.4.1 Testing of concrete roofs
Concrete roofs of structures which are to contain aqueous liquids shall be watertight and shall, where
practicable, be tested prior to the Installation of any waterproof membrane by lagooning with water to
a minimum depth of 25 mm for a period of 24 hours. Where it is impracticable, because of roof falls or
otherwise, to contain 25 mm depth of water, the roof shall be thoroughly wetted by continuous hosing
for a period of not less than 6 hours.
In either case the roof shall be deemed satisfactory provide there are no visible leaks or damp patches in
the soffit.
4.12.4.2 Testing of water retaining concrete structures
After cleaning, and as far as practicable before any earth or other filling is placed against the outside
wall faces, concrete structures designed to retain an aqueous liquid or sludge shall be filled with water
at a uniform rate of not greater than 2 m in 24 hours to overflow level. A period shall be allowed by the
CO(s) for stabilization, after which the water level shall be recorded by approved means at 24 hours
periods for a test period of 7 days. During the test period the total permissible drop, after allowing for
evaporation and rainfall, shall not exceed 1/500 of the average water depth 10 mm, whichever is less.
Notwithstanding the satisfactory completion of the above test, any leakage visible on the outside faces
of the structure shall be stopped. Any caulking or making good of cracks in the wall section shall, where
practicable, be carried out from the inside face.
Backfilling around concrete water retaining structures is only permitted to start once the water
tightness test has been passed.
50 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
5 Building works
5.1 General
This sub‐section covers the requirements for the construction of buildings and includes all building
works, except earth and concrete works. The work required under this sub‐section shall include all
labour, materials, equipment, remedy of deficiencies, site clearance and all other appurtenant works
required to complete all building works specified herein.
The CO(s) shall, unless otherwise specified herein, supply all materials, equipment, temporary works and
labour necessary to perform, maintain and complete the building works.
5.1.1 Standards and rules
The CO(s) shall carry out the works described in this Section in accordance with the appropriate DIN
standards or equivalent.
5.1.2 Approval of materials and workmanship
The supply of all materials and items shall be subject to the approval of the PO Engineer. The CO(s) shall
provide such samples as the PO Engineer may require in advance for the approval and, when approved,
the quality of materials and workmanship shall be at least equal to the approved samples.
5.2 Masonry works
5.2.1 Materials
Bricks and blocks a)
Bricks shall be clay facing bricks manufactured locally. The quality shall correspond to DIN 105. Blocks
shall be dense concrete blocks in accordance to DIN 18153 with a compressive strength of more than
7.5 N/mm². Bricks and blocks shall be hard, sound, square and clean with sharp, well defined arises.
The CO(s) shall submit samples of each type of bricks and blocks used in the works and obtain the PO
Engineer's approval before placing Orders with suppliers. Strength test certificates performed on the
basis of appropriate DIN Standards shall also be submitted on request of the Engineer.
Reinforcement for brickwork b)
Reinforcement of brickwork shall be in accordance with DIN 488, DIN 1045 and DIN 1053.
Reinforcement for Brick shall be plain round bars B ST 22/34 GU or ribbed bars B St 22/34.
Reinforcement shall be detailed, stored and tested as specified for Concrete Works.
Fixings for brickwork c)
Fixings shall be, if not otherwise specified by the PO Engineer, of stainless steel for sheet, strip, plate and
bars in accordance to DIN 17440.
Sand d)
Sand shall be clean and sharp course grit, fresh water river or pit sand conforming in all respects to DIN
1053 and DIN 18550 and shall be re‐washed on site if the silt, loam or clay content exceeds the limits
prescribed in DIN 4226. The sand shall be obtained from a source approved by the PO Engineer.
Renewable Energy Guidelines Nov. 2013 51
Volume 12 Civil Works
Cement e)
Cement shall be sulphate resisting Portland cement as specified in DIN 1164. The source of cement is
subject to the approval of the PO Engineer and shall not be changed without his/her prior approval.
Water f)
For the mixing of mortar and plaster the CO (s) shall provide tap water, if not otherwise directed or
approved by the PO Engineer.
5.2.2 Mortar mix
Masonry mortar for setting blocks and bricks shall be of the quality group III set out in DIN 18550. The
Proportion shall be 1 part cement to 4 parts sand or as otherwise directed or approved by the PO
Engineer and or specified in the drwaings. Lime shall be added to the mix in an amount compatible with
workability. Mortar constituents shall be measured by volume using clean gauge boxes.
Mortar shall be mixed in a mechanically operated mortar mixer for at least three minutes after all
ingredients are in the drum. The mixing by hand will only be permitted when the quality of hand mixing
is comparable to mechanical mixing.
Mortar shall be used within 2 hours after discharge from the mixer at normal temperatures. No mortar
shall be used after the initial set has taken place. Reconstitution of mortar will not be permitted.
5.2.3 Workmanship
All masonry shall be laid plumb and true to lines and built to the thickness and bond required. Masonry
shall be carried up in a uniform manner. No one portion shall be in raise more than one meter above
adjacent portions, except with the approval of the PO Engineer.
Sample panels of 1 m size shall be prepared for each type of facing brickwork or block work, including
jointing or pointing, and the CO(s) shall not commence face work without the approval of the PO
Engineer. Face work shall be kept clean during construction and until completion of the Works.
Under hot and dry weather conditions, bricks and blocks shall be stacked on a hard standing level so as
to prevent the absorption of water. Suitable shading shall be provided to prevent high temperatures
within the brick and block Stacks. Clay brickwork and block work shall be kept wet to the minimum
extent required to prevent mortar drying out prematurely.
All bricks shall be wetted before being laid. Clay bricks shall not be used until completely cold from the
kiln. Freshly laid brickwork/block work shall be protected during interruption caused by weather rain
and at the completion of each day´s work.
Face work shall be kept clean during construction and until practical completion. Scaffold boards shall
be kept clear of the building at night and during heavy rain. Rubbing to remove stains will not be
permitted.
Facing bricks of varying colour shall be distributed evenly throughout the work so that no patches
appear. Different deliveries, which vary in color shall be mixed to avoid horizontal stripes.
Brickwork and block work abutting concrete columns, walls and beams shall be tied with stainless steel
ties in accordance with the relevant references and as directed by the design. Additional ties shall be
supplied at openings. Walls which are to be fair face shall have selected bricks and blocks with perfect
arises and flat surface structures and with faces in line.
52 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
5.2.4 Bricklaying and block laying in cold weather
Materials used in bricklaying and block laying shall be frost free and no bricks or blocks shall be laid
when the ambient temperature is below ‐5°C, unless special precautions are taken. The CO(s) shall
ensure that any additive used in the mortar does not cause a variation in the colour of the joints.
Completed work shall be protected adequately during cold weather.
5.2.5 Exposed concrete blocks
Concrete block work shall be laid in Stack bond and, unless otherwise directed, with joints not exceeding
1 cm and uniform throughout. All blocks shall be laid in a full bed of mortar applied to shells only.
Intersecting bearing walls shall be tied together with stainless steel ties at one meter vertical spacing.
Where directed, concrete blocks shall be reinforced and concrete blocks lintel type shall be built in
above wall openings.
Control joints shall be installed at the intersection with structural concrete and elsewhere where joints
are useful. Joints not detailed otherwise shall be racked out to a depth of 2 cm for the full height of the
wall and be caulked. Joints are to be examined to locate cracks, holes or other defects and all such
defects shall be remedied with mortar and pointed.
5.2.6 Concrete blocks to receive plaster
Concrete block walls to be plastered may be laid with bonds described above. Joints are to be left rough
to assist in bounding of plaster. Control joints in plastered block shall be carried through the plaster. The
joint shall not be plastered.
5.2.7 Brickwork
Solid brick walls shall be laid in common bond with all joints filled solidly with mortar and backs fully
purged to form solid masonry structure. Joints of walls to receive plaster shall be lightly raked to provide
a bond for plaster. Control joints in brick walls shall be carried through the plaster. The joint shall not be
plastered.
5.2.8 Lintels, miscellaneous
The CO(s) shall build in or provide all miscellaneous items to be set in masonry including lintels, frames,
reinforcing steel, electrical boxes, fixtures, sleeves, grilles, anchors and other miscellaneous items. All
anchorage, attachments and bonding devices shall be completely covered with mortar.
5.2.9 Cleaning
Masonry work to be exposed shall be thoroughly cleaned. Mortar smears and droppings on concrete
block walls shall be dry before removal with a trowel. Masonry work may be cleaned using a mild acid
solution.
5.2.10 Damp‐proof courses
As a minimum requirement, damp‐proof courses shall be in accordance with DIN 4117 and DIN 4122.
Bituminous sheet damp‐proof courses shall be laid on a level bed of cement mortar with a minimum lap
of 75 mm at angles and joints and neatly pointed in matching mortar on exposed edges. Horizontal and
Renewable Energy Guidelines Nov. 2013 53
Volume 12 Civil Works
sloping damp‐proof coursing over door openings shall be in single pieces of material of a length to
extend 225 mm at both sides beyond the width of the frame.
5.2.11 Waterproof building paper
Waterproof building paper shall be laid beneath structural concrete. The paper shall be laid with
150 mm lapped joints, which shall be treated and sealed with an approved bituminous solution. The
weight of the paper shall not be less than 0.3 kg/m².
5.3 Plastering
5.3.1 Materials
Sand a)
Sand shall be clean and sharp course grit, fresh water river or pit sand conforming in all respects to DIN
1053 and DIN 18550 and shall be re‐washed on site if the silt, loam or clay content exceeds the limits
prescribed in DIN 4226. The sand shall be obtained from a source approved by the PO Engineer.
Cement b)
Cement shall be sulphate resisting Portland cement as specified in DIN 1164. The source of cement is
subject to the approval of the PO Engineer and shall not be changed without his prior approval.
Water c)
For the mixing of mortar and plaster the CO(s) shall provide tap water, if not otherwise directed or
approved by the PO Engineer.
5.3.2 Plaster mixing
Plaster shall be mixed with proportions according to DIN 18550. The constituents shall be measured by
volume and water added in an amount compatible with workability.
Plaster shall be mixed in a mechanically operated plaster mixer for at least long enough to make a
thorough, complete intimate mix of the materials. The mixing of plaster by hand shall not be permitted,
unless otherwise directed.
The mixer, bunker, gauge boxes and all tools shall be kept clean, and care shall be taken to ensure that
fresh plaster is not contaminated with set plaster.
5.3.3 Workmanship
Plaster shall be of 2 or 3 coats. If plaster is to be applied to smooth surfaces, a dash coat shall be applied
as a bonding surface. The dash coat shall be of mush consistency, composed of 1 part Portland cement
and 15 parts of sand.
The plaster coats shall be applied according to the thickness given below, whereby additional thickness
which will be required due to unevenness in the masonry surface is not included:
54 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
Location: Ceiling Interior wall Finish
Thickness of first coat: 15 mm 10 mm 10 mm
Thickness of intermediate coat: 6 mm 9 mm
Thickness of finish coat: 10 mm 4 mm 6 mm
Total thickness: 25 mm 20 mm 25 mm
5.3.4 Preparation of surfaces
Surfaces that are to receive plaster shall be carefully examined by the CO(s) and any unsatisfactory
surface shall be repaired as directed by the Engineer. Where fixtures have to be installed prior to
plastering they shall adequately be protected from damage during plastering. Concrete masonry and
brick surfaces shall have sufficient roughness to provide proper bond and shall be dumped by brushing
or spraying with water followed by plastering.
5.3.5 Plastering
The dash coat shall be applied with a whisk broom or fiber brush and be kept moist for 48 hours before
the first coat is applied to the dash coat.
Before the first coat hardens, the surface shall be scratched to provide bond for the intermediate coat.
This coat shall be kept moist for not less than 24 hours and be allowed to set for not less than 14 days
before application of the intermediate coat.
The surface of the intermediate coat shall be brought to a true and even surface, then roughened with a
wood float before setting to provide a bond for the finish coat.
The finish coat shall be applied while the intermediate coat is moist and if the intermediate coat dries
out it shall be wetted evenly. The finish coat shall be first floated to a true and even surface and then
trowelled to a smooth and even finish.
5.3.6 Completion of work
Completion of work includes curing (moistening for at least 3 days) and removal of deficiencies. Upon
completion of the work, all plaster surfaces shall be cleaned and all rubbish, debris and excess material
and equipment shall be removed.
5.3.7 Waterproof plaster
Waterproof plaster shall consist of waterproofing compound, cement and sand mixed in strict
accordance with the manufacturer's specification. The water proofing compound shall be a mass
product of a repudiated manufacturer and shall be approved by the PO Engineer.
5.3.8 Tolerances
All surfaces shall be true to line, level, plumb and all junctions, angles and arises truly scare. On two or
three coat work, the plaster surface shall not show any deviation greater than specified in DIN 18202 for
accuracy class B.
Renewable Energy Guidelines Nov. 2013 55
Volume 12 Civil Works
5.4 Screeds
5.4.1 General
Workmanship and construction shall generally conform to DIN Standards 18353 and 18560 or
equivalent Standards.
Materials used for mortar shall be measured in gauge boxes. All concrete surfaces shall be adequately
prepared and keyed to receive screeds. The screeds to be carried out have to be placed within buildings
and shall be dense aggregate cement screeds.
5.4.2 Floor screeds
To form falls for drainage or to improve the surface finish of a concrete slab when necessary, a screed
shall be laid on it. In basement the slope of the screed shall be at least 1% towards the pump sump of
the basement drainage pump.
Floor screeds in buildings shall be laid monolithically to a thickness of 50 mm and be laid separately.
The preparation of base concrete shall include the removal of laitance from the concrete surface to
receive screed and the removal of all loose concrete, dust and dirt by thorough washing with water.
The screed mix shall be prepared in accordance to DIN 18550 and shall be thoroughly and efficiently be
mixed dry by mechanical means until a uniform distribution is obtained prior to adding the water. The
water content shall be kept as low as it is necessary to allow for sufficient workability for laying and
compacting. Where only small quantities are required, mixing might be carried out by hand on clean
watertight surface with the approval of the PO Engineer.
The screed mix shall be placed between forms, rigidly fixed on a firm foundation and set true to level
within +/‐ 3 mm, and shall be fully compacted by means of a screed board providing laitance is not
brought to the surface. The screed wearing course shall be tamped with a wood float and trowelled with
a steel trowel to produce a smooth finish.
The screed mix shall be placed between the forms (and or other bays) worked around the penetrations,
duct covers, manhole covers, gutters, balustrade Standards, pipes, etc., and shall be fully compacted by
means of a screed board, or other suitable compacting equipment, providing laitance is not brought to
the surface.
5.4.3 Joints
All edge joints of floor screeds shall be simple butt joints without filler. Screeds laid over construction
joints in concrete shall be separated by 10 mm impregnated oakum strips or the like. Joints in wearing
courses shall be 10 mm polysulphide according to DIN 18540.
5.4.4 Tolerances
The finished surface of base course screeds, when laid, shall not depart more than specified in DIN
18202 for accuracy class B.
Floor screeds, when laid, shall be free of all defects and any work which shows signs of bond failure,
hollow patches, crazing, cracking or any other defects will not be accepted and shall be removed and
replaced with acceptable work by the CO(s) .
56 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
The extent of the work to be removed and the method to be used in the removal and replacement of
this work shall be to the approval of the Engineer. All surfaces shall be approved by the Engineer before
further work.
5.5 Flooring
5.5.1 General
All materials and structural components not covered by DIN Standards or equivalent may be used
subject to the PO Engineer's consent only. The floorings shall be such as to provide a cover surface that
can well be walked on and must not give any rise to any unreasonable inconvenience.
5.5.2 Materials
Concrete paving slabs shall be 50 mm thick, hydraulically pressed pre‐cast concrete slabs in accordance
with DIN 18500.
Terrazzo shall be in accordance with the appropriate Standard. The marble chippings shall be of an
approved quality in irregular pieces with no flaky pieces.
PVC flooring material shall comply with the requirements of DIN 16951 and DIN 16952 and shall be
temperature resistant, waterproof, abrasion resistant, flameproof, pigment or color proof to light,
evenly colored throughout, resistant to chemicals, fats, acids and alkaline, odorless, easily laid and
flexible, non‐porous and slip proof.
All adhesives shall have suitable properties to ensure a firm and durable bond. They must not adversely
affect either the flooring nor the underlay or the base and shall be odorless once applied.
All fillers and levelling compounds shall have a firm and durable bond to the base, provide a good
bonding surface for the adhesive and be of suitable property so as to give an adequate support to the
covering. They must have no adverse effect on base, adhesive, underlay, or covering.
5.5.3 Workmanship
The CO(s) shall examine the base to verify whether it is in suitable condition to carry out his work. Any
doubts the CO(s) may have in this connection, shall be communicated by him to the PO Engineer
immediately in writing.
All materials and structural components whose processing is subject to manufacturer's instructions shall
be processed accordingly. The CO(s) shall clean the flooring and treat it in accordance with the
manufacturer's instructions for flooring materials.
The CO(s) shall furnish the PO Engineer with the written instructions for the care and the maintenance
of the flooring.
5.5.4 Preparation of surfaces
The surfaces must be cleaned prior to flooring. The base for covering to be placed without underlay shall be smoothed with filler compound. In the case of major unevenness a suitable levelling compound shall be used.
Any filler or levelling compound shall be applied so that it will bond firmly and | durably to the base, will not crack and will adequately withstand pressure. Any screeds such as magnesia and anhydride screed to which the filler or levelling compound will not sufficiently bond, shall receive a priming coat.
Renewable Energy Guidelines Nov. 2013 57
Volume 12 Civil Works
5.5.5 General requirements for application
Workmanship generally shall be in accordance with DIN 18352 and DIN 18365. Floorings shall be placed
without underlay unless otherwise specified.
Deviations in color, which are not of minor importance and not due to the flooring pattern shall not be
allowed if marring the overall appearance of the flooring.
Courses with pattern repeats shall be laid so as to suit these. Where courses run towards doors,
recesses and the like, they shall be laid so to cover also the floor of areas such as door openings,
recesses etc. Strips of slabs may be used as coverings of such floor areas.
Plastic flooring shall not be welded unless otherwise specified or expressly required in the flooring
material manufacturer's processing instructions.
Baseboards of the same material as the flooring material with a minimum height of 6 cm have to be
installed at all side walls.
5.5.6 Pre‐cast concrete slabs
All pre‐cast concrete slabs shall be laid in bays not exceeding 10 m in length, the bays being separated
by an expansion joint 10 mm wide.
5.5.7 Thin floor coverings
Flexible PVC sheeting or tiles shall be laid on a level and smooth background generally consisting of
anhydride screed. The screed surfaces shall be clean, dust‐free and dry. Tiles shall be laid in strict
accordance with manufacturer's instructions.
5.5.8 Tiling
5.5.8.1 General
Tiling shall comprise all required labor, equipment and the supply of the appurtenant materials and
structural components including off‐loading and storage at the site. Tiling and flooring shall be applied in
accordance with the finishes, specified in the Particular Specification. Workmanship and construction for
tiles to floors and walls shall generally be in accordance with DIN 18352. All materials and structural
components, which are not standardized shall be used only with the approval of the PO Engineer.
All tiles and flags for which there are several grades available shall be of the best Standard commercial
grade, unless grade is stipulated in the Particular Specification.
Before starting the work, the CO(s) shall ascertain the PPAF and PO’s selection of patterns and colours
and the CO(s) shall furnish the PO Engineer with duplicate samples of the patterns and colours of the
materials selected.
Tiling shall be free of any defects and any work that shows signs of bond failures, hollow patches,
misalignment, cracking or any other defect. Defective work will not be accepted and shall be removed
and replaced by acceptable work.
5.5.8.2 Materials
In general, tiles and flags shall meet the quality requirements of DIN 18155, DIN 18158 and DIN 18166.
Where tiles and flags are not standardized, the quality features shall satisfy the Standard commercial
58 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
requirements (top surface, parallelism of edges, colour, water absorption). All floor and wall tiles shall
be from the same batch.
Glazed ceramic tiles for walls shall be in the colour selected by the PO, true to shape, flat, free from
flaws, cracks and crazing, uniform in colour, keyed on the back and shall comply with DIN 18155. The
ties shall be of a suitable type, size, color and acid resistance.
Ceramic floor tiles shall be oil and acid resistant, true to shape, flat, free from flaws, cracks and crazing,
uniform in colour and of an approved non slippery type, make and color. Dimensions and tolerances
shall comply with DIN 18158 and DIN 18166.
Cement based adhesives shall comply with the requirements of DIN 18156. Other adhesives shall be
subject to the approval of the PO Engineer and mixed and used strictly in accordance to the
manufacturer's printed instruction. Mortar materials and adhesives shall not alter the top surface of the
tiles.
5.5.8.3 Preparation of surfaces
Surfaces shall be prepared before covering with tiles in strict accordance with the manufacturer's
instructions.
5.5.8.4 Preparation of tiles
Tiles, which are to be laid in cement mortar shall be soaked in clean water for 1530 minutes before
fixing and allowed to drain for 10‐15 minutes. Any surplus water shall be removed from the backs before
laying. Tiles to be fixed with adhesives shall not be soaked or wetted before laying. All cutting to tiles
shall be fair cutting using a tue cutter.
5.5.8.5 Placing
In interior finishing works all tiles, flags or mosaic shall only be set and laid before the fixing of Windows
and door frames and trims, and after stop rails, plumbing installations and the application of plaster. All
tiles, flags and mosaic shall be set or laid plumb, in true alignment and horizontal or at the slope
specified, without any projections, with regard to any specified reference or level lines.
5.5.8.6 Fixing and bedding
Thin tiles shall be generally adhesive fixed. Backgrounds shall be cleaned and primed according to the
manufacturer's instructions and the adhesive shall be applied by the notched trowel technique and
trowelled over the area to receive tiles in 4 mm thickness. Tiles shall be pressed in as recommended by
the manufacturer.
Thick tiles shall be generally bedded in cement‐sand mortar, at least 10 mm thick. Any surplus mortar
which adheres to the face of the tue shall be wiped off with a damp cloth before it sets hard.
The external angles and side and top edges shall be formed with rounded edge tiles. At intersections,
returned rounded edge tiles shall be used.
Renewable Energy Guidelines Nov. 2013 59
Volume 12 Civil Works
5.6 Roofing
5.6.1 General
The specification for waterproofing and insulation of flat concrete roofs shall be designed and laid
according to the Afghan norms or equivalent and taking into account the relevant manufacturer's
instructions). Work shall follow the general principles given below. The CO(s) may propose a different
System, which shall be subject to the approval of the PO Engineer.
The waterproofing and insulation of concrete roofs shall consist of at least 2 coats of polymer‐bitumen /
rubber membranes.
The work shall consist of supplying, laying and finishing complete insulation and roof coverings and shall
include the Provision of all necessary skirting, copings, flashings etc. On completion, all roofs shall be left
sound and watertight and in neat and clean condition. All roof finishes shall be carefully worked or fitted
around pipes and openings.
Roofing Systems shall be in general the "inverted roof or "protected membrane roof System" where the
waterproof membrane is laid directly onto the structural slab and the insulating layer is then laid on the
membrane and protected by a layer of files. Any special working details prepared by the CO(s) must be
submitted to the PO Engineer for approval.
The top surface of the roof slab shall be finished by cement plastering of minimum thickness 20 mm. A
50 mm x 50 mm mortar or wooden fillet shall be fixed in the corner between the horizontal slab and the
vertical parapet before the water proofing membrane is formed, fillets shall also be fixed in the corners
of gutters.
The finished roof slab surface must be clean, dry, smooth and free of roughness or dips. The plastered
surface of roof slab must be allowed to dry before the sheets are applied. Drying time is dependent on
the weather and may take anything from 8 days to 3 weeks.
5.6.2 Waterproofing and insulation
The structural slab or surface screed on it shall be primed before application of the membrane in
accordance to the manufacturer's instructions. The insulation layer shall have a minimum density of
35 kg/m².
Depending on the different construction types, the sheets can be fully bonded to the Substrate by torch,
spot bonded or loose laid. Torch‐bonding is carried out with a suitable gas torch burner connected to a
propane gas cylinder.
The sheets are overlapped longitudinally by 100 mm, while the head laps of the membranes shall not be
less than 150 mm. The bonding is carried out by torch application in such a way that a continuous bead
of melted bitumen comes out from the overlap. So as not to remove the protective top layer, the use of
trowel is to be avoided.
However the membranes must not be overheated and a further sign of correct application is that an
excessively large bead of melted compound does not come out from the overlap.
The waterproofing membranes and coatings shall be brought up the inside of the roof parapet to a
height of at least 150 mm. The top sheet must be protected by mineral coating or suitable painting.
Expanded polystyrene slabs or other approved foam insulation 40 mm thick at least shall be stuck down
to the roof with a coat of the approved waterproofing compound.
60 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
Each slab of insulation shall be bounded by a key interlocking with adjacent slabs, to ensure the
continuity of the insulation.
A vapor barrier shall be applied below the insulation layer.
5.6.3 Covers, flashings and rainwater outlets
Pre‐cast cement roofing tiles shall be formed with a minimum 10 mm facing of one part white cement
and three parts of sand, set on a backing of sulphate resistant cement mortar with a minimum cement
content of 300 kg/m³.
Flashings shall be formed out of 0.8 mm aluminum with natural mill finish. Accessories such as hooks,
nails, screws and clamps shall be of the same material and alloy.
Screeds shall be prepared of cement, sand and water in accordance to the requirements stipulated for
screeds.
Rainwater outlets shall be a proprietary type approved by the PO Engineer. Outlets shall drain from the
top interface between the waterproof membranes.
Rainwater guttering for flat roofs shall have vertical pipes of diameter, such that a minimum cross‐
sectional area of 100 mm² is provided for each square meter of roof area.
5.6.4 Workmanship
Workmanship shall be carried out in accordance with DIN 18338. The roof surfaces shall be uniform,
compact and free from debris.
Waterproof membranes shall be 1.5 mm thick self adhesive rubber bitumen applied strictly in
accordance to the manufacturer's instructions. The membrane shall be continuous and take up
abutments and pipes to above the insulation layer. Exposed membrane shall be solar protected. The
waterproof membrane shall be dressed and bonded into rainwater outlets and under flashings.
The insulation board shall be not less than 50 mm thick closed cell extruded polystyrene loose laid in a
single layer with tight staggered butt joints in accordance with the manufacturer's instructions. The
board shall be trimmed to fit any fillets used under the waterproof membrane.
Flashings shall be sheet aluminum neatly cut to the width and length required. The aluminum shall be
carefully bent using a slightly rounded former so as to avoid surface cracking. Where surface fixing is
required, the sheet shall be predrilled and fixed with rust free screws to proprietary fixings or hardwood
grounds let into the surface of the base concrete or brick work.
Lightweight screeds shall be laid in accordance with the manufacturer's instructions and to falls not less
than 1:40 with a thickness of 100 mm. The screed shall be laid in two courses and in bays not exceeding
15 m², laid alternatively and finished with a mortar topping of 1:4 cement/sand mortar. Immediately
after laying, the screed shall be protected from wind and sunlight and cured for 7 days.
Renewable Energy Guidelines Nov. 2013 61
Volume 12 Civil Works
5.7 Timber works
5.7.1 General
A high Standard of workmanship and materials shall be achieved in the works. The completed timber
work shall be durable, well finished and designed and constructed to arrive at a service lifespan of at
least 40 years.
Workmen employed in the manufacture and Installation of timberwork shall be experienced carpenters.
5.7.2 Materials
Timber shall be of best quality, sound, in good condition, reasonably free from shakes and free from
loose dead knots, insect attack, decay, twisting and warping. Timber shall be properly seasoned to suit
the purpose for which it is intended. Only knots with characteristics similar to those detailed in DIN 4074
will be allowed. Where timber is prescribed as "selected" it shall be free from knots.
Softwood shall be either redwood, specially selected from the best unsorted and joinery quality or
douglas fir of selected merchantable quality or better. Hardwood shall be selected and of best quality; it
shall be particularly checked for infestation by pinhole borers. Selected hardwood shall comply with DIN
4074, grade IA.
All plywood, chipboard or materials incorporating chipboard shall not be used in the works, except with
express permission by the PO Engineer in writing.
5.7.3 Samples
Before commencing work, the CO(s) shall submit samples of all types of timber to be used in the works
for the approval of the PO Engineer. Timber, or carpentry and joinery units of which the material on
delivery to the site does not conform to the Standard of approved samples will be rejected and replaced
by the CO(s) at his own expense.
5.7.4 Ironmongery
The CO(s) shall provide all necessary ironmongery including matching screws, bolts, plugs and other
fixings. The use of nails for ironmongery fixing will not be permitted.
Ironmongery shall be of the best quality and subject to the approval of the PO Engineer. Unless
otherwise specified, ironmongery shall be of solid brass.
5.7.5 Fabrication
The carpenter shall perform all necessary mortising, tenoning, grooving, matching, housing, rebating
and all other works for correct jointing. He shall also provide all metal plates, screws and other fixings
that may be specified or necessary for the proper execution of the works and he shall carry out all works
necessary for the proper construction of all framings, linings etc. and for their support and fixing in the
works.
No nails shall be used to assemble or fix hardwood, major supports or ironmongery. Screws used in
exposed locations and/or for hardwood shall be brass and complete with brass surrounds.
62 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
5.7.6 Timber components
Flush doors shall have a minimum thickness of 40 mm and shall be faced both sides with hardwood
veneered faces. The core of solid core flush doors shall be constructed of longitudinal laminations of
precision planed timber, butt jointed and glued with resin based adhesive under hydraulic pressure. All
edges shall be levelled and lipid with hardwood tongued into the edge of the door.
Hardwood doors shall be constructed out of teak or similar approved hardwood, with 100x38 mm Stiles,
125x38 mm top rails and 225x38 mm middle and bottom rails. Where required, the doors shall be
glazed with 6 mm wire polished plate glass, fixed with hardwood glazing beads.
Frames, architraves and extension pieces shall be manufactured from red or whitewood timber and
shall include the use of finger‐jointed material. If exposed in the laboratory, the frames must be in
hardwood.
5.8 Metal windows and doors
5.8.1 Metal windows, louvers and doors
Metal Windows and doors shall be handled with care and until fixed shall be stacked on edge on clean
surfaces. In brick openings, frames shall be fitted with fixing lugs in adequate number, and bedded in
mortar. In concrete openings, frames shall be plugged to the walls using zinc‐coated screws. To avoid
corrosion of aluminum alloy frames, screws and other metal fixing in contact with them shall be of
aluminum, zinc or cadmium plated. In no circumstances shall copper fixings be used. Frames shall not be
used as centering for brickwork or to support a lintel. Frames shall be carefully pointed in 1:3 cement
mortar and, after raking out the gap, shall be pointed with mastic.
5.8.2 Kind of windows and doors
When not otherwise specified, the CO(s) shall use surface treated anodized aluminum Windows and
doors which shall be robust and of good quality. Extruded aluminum members shall be fabricated
conforming to DIN 1784. Where members are formed from sheet materials they shall be fabricated con‐
forming to DIN 1783. The main elements of the Aluminum solid section outer frame shall be at minimum
tolerance not less than 2.0 mm thick. The thickness of all other structural elements of the sections shall
be at minimum tolerance not less than 1.2 mm except for weather‐stripping retaining flanges and
glazing beads which may be thinner.
All Aluminum alloy parts shall be finished satin matt and anodized in accordance with DIN4113.
Weather‐stripping shall:
be made from materials known to be compatible with aluminum;
not shrink or warp or adhere to sliding surfaces or closing surfaces;
not promote corrosion when in contact with the aluminum alloy used; and,
be resistant to deterioration by weathering.
Joints in frames shall be made neatly and accurately either by welding or by mechanical means (e.g.
cleating and screwing) and may have flush, stepped or lapped surfaces. Welded joints shall be cleaned
off smooth on the surfaces, which are exposed when the window or door is in the closed position or
where they come into contact with glazing.
Hinges and pivots shall be either of suitable corrosion‐resistant materials or, if not compatible with
aluminum, shall be separated from the aluminum by materials which are compatible with it. Hardware,
Renewable Energy Guidelines Nov. 2013 63
Volume 12 Civil Works
including fixings, shall be of suitable corrosion resistant materials. Materials or finishes which are not
compatible with aluminum shall not be used unless they are satisfactorily separated from the aluminum
by materials which are compatible with it.
Glazing beds, gaskets, glass adaptors and glazing compound shall be of materials compatible with
aluminum and finishes thereon.
Windows and doors shall be such that glazing and re‐lazing on site is possible without the need to
remove the outer frames from the structure of the building.
5.8.3 Roll‐down gates
Roll‐down gates shall be made from zinc‐coated steel elements and applied if the door/gate width
exceeds 3 m. They shall be lockable. Roll‐down gates with a width larger than 4 m shall be driven by
electric motor, but also manually operable.
5.9 Hardware
5.9.1 General
The CO(s) shall furnish and install all finish hardware to complete the work as specified. The CO(s) shall
submit samples of all hardware to the PO Engineer for approval. All hardware shall have the required
screws, bolts and fastenings necessary for proper installation, wrapped in paper and packed in the same
package as the hardware. Each package shall be legibly labeled, indicating that portion of the work for
which it is intended.
All hardware shall be of the best grade, entirely free from imperfections in manufacture and finish.
Finish of all hardware shall be dull stainless steel unless otherwise noted.
5.9.2 Hardware description
1. Tabular cylinder locks: stainless finish
2. Entry, exit and office doors: keyed on side, button opposite side
Passage doors: knobs both sides; no lock Storage rooms: single knob with key; Toilet rooms: stainless
outside, chrome inside, pin opening outside for emergency with button inside.
All keyed locks shall have a master keys for same building. All locks shall have two keys each. Door
closers shall be heavy duty type with stainless cover.
Standard Door hinges: 10 x 10 cm stainless steel, three per door.
Window hardware: Windows indicated to be pivot type shall be furnished with a pair of window fittings
(friction stays), a window pull and one barrel bolt lock. Window fittings shall be galvanized or stainless
steel. Window pull shall be 2.5 x 10 cm with 4 screws and barrel bolt 10 cm long, 6 mm bolt.
Installation: Unless otherwise indicated, all hardware installation and hanging shall be done at the site.
64 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
5.9.3 Glazing
5.9.3.1 General
The CO(s) shall supply the glass required in those items of plant, furnishings and figments included in the
TOP. Glass shall be of quality in accordance to DIN 1249 or equivalent. Sheets shall be selected quality
glazing and of approved weight. Labels showing the glass manufacturer's name, type of glass thickness
and quality will be required on each piece of glass and shall remain on the glass until it has been set and
inspected.
5.9.3.2 Materials
Clear float glass shall be 6 mm thick. Obscured glass shall be rough cast to an approved pattern,
untainted and of 6 mm nominal thickness. Wired glass shall be transparent with a polished surface,
6 mm thick, selected and cut parallel to the reinforcement.
Putty for glazing to timber frames shall be in accordance to DIN 18540, and to metal frames, it shall be
of approved manufacture.
5.9.3.3 Size, delivery and storage
Dimensions of glass and frame shall provide minimum clearance equal to glass thickness for single glass
on all four sides. The sealed space between face of glass and applied glazing stops shall be not less than
3 mm minimum.
Glass shall be delivered to the site in suitable Containers allowing to protect the glass from weather and
breakage.
5.9.3.4 Installation
Clear glass shall be used except where ordered otherwise. The glass shall be cut and installed without
any visible lines or waves running horizontally.
Glazing in wood shall have rebates and beds primed and painted. The glass shall be firmly seated into
the previously bedded and back‐bedded rebate with glazing compound and secured in place with wood
beds, attached with not less than 25 mm finish nails or flat headed screws, countersunk and set
approximately at 15 cm centers. Nails and screws used in beds shall be corrosion resistant.
5.9.3.5 Cleaning
All glass shall be cleaned at the completion of construction and any broken glass replaced. The glazing
shall be maintained in a clean condition until the date of handing over the works.
5.10 Sanitary installation
The CO(s) shall design and construct the interior plumbing system with connection to the exterior
sewerage system. The CO(s) shall design and construct the exterior sewerage system and piping as a
three‐chamber septic tank for at least 10 Person Equivalents (PE). Outfall of this treatment shall be
downstream the tail race channel.
Renewable Energy Guidelines Nov. 2013 65
Volume 12 Civil Works
5.10.1 Connections to equipment and fixtures
The CO(s) shall provide all equipment and necessary material and labor to fixtures connect to the
plumbing system all fixtures and equipment having plumbing connections, which are specified
elsewhere. All connections to the sanitary drainage system shall be trapped. The supply line to each
item of equipment or fixture shall be equipped with a cut‐off valve to enable Isolation of the item for
repair and maintenance without interfering with operation of other equipment or fixtures.
5.10.1.1 Cutting and repairing
The work shall be carefully laid out in advance, and no excessive cutting of construction will be
permitted. Damage to buildings, piping, wiring, equipment or appurtenances as a result of cutting for
Installation shall be repaired by persons skilled in the trade involved.
5.10.1.2 Protection to fixtures and equipment
Pipe openings shall be closed with fixtures and caps or plugs during Installation. Fixtures and equipment
shall be tightly covered and protected against dirt, water and chemical or mechanical injury. Upon
completion of all work, the fixtures, materials and equipment shall be thoroughly cleaned, adjusted, and
operated. Belts, pulleys, chains, gears, couplings, protecting setscrews, keys and other rotating parts
shall be located so that any person in close proximity thereto shall be fully enclosed or properly
guarded.
5.10.1.3 Sanitary, wastewater and vent piping
Pipe materials shall be uPVC. Fittings on PVC pipes shall be PVC socket type and shall be installed by
solvent method.
5.10.1.4 Sanitary, wastewater and vent piping installations
Horizontal waste and drain pipes shall have a minimum slope of 10 mm per meter. Vent pipes in roof
spaces shall be run as close as possible to the underside of the roof without forming traps in pipes, using
fittings as required. Vent and branch‐vent pipes shall be so sloped and connected as to drip back to the
vertical Stack by gravity.
Changes in pipe size on sanitary and wastewater drain lines shall be made with reducing fittings. Use of
bushings will not be permitted. Changes in direction shall be made by the appropriate use of 45° Y‐
branches, long or short‐sweep 90°, 45°, 22°, or 11°, or by a combination of these or equivalent fittings.
Sanitary tees and 90°‐bends or elbows may be used in drainage lines only where the direction of flow is
from horizontal to vertical, except elbows may be used where the change in direction of flow is either
from horizontal to vertical or from vertical to horizontal, and may be used for making necessary offsets
in vertical lines.
Slip joints will be permitted only in trap seals or on the inlet side of the traps. Installation of pipes and
fittings shall be carried out in accordance with the manufacturer's recommendations. Threaded joints
shall have ISO/R7 pipe threads with graphite or inert filler and oil, with an approved graphite compound
or with polyethylene tape applied to the male threads only.
5.10.1.5 Buried drainage pipes
Underground drainage pipes of drainage systems shall be minimum 150 mm diameter of the material
specified above.
66 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
When passing under buildings, paths, roadways, etc., drainage piping shall be laid accurately to falls on a
bed of class B 10 concrete, 15 cm thick and 30 cm wide and after laying shall be entirely encased in class
B 10 concrete. Piping outside building shall be laid on a bed of class B 10 concrete 15 cm thick and 30 cm
wide and shall be hunched upon both sides with class B 10 concrete. Piping fixed vertically is to be well
secured to walls, etc., with approved metal holder bats at every joint, built into walls as directed.
Rodding and inspection eyes are to be provided at all ends and junctions for cleaning purposes.
The CO(s) shall give notice in writing when drainage trenches have been excavated to their full depths
and trenches shall be inspected and approved by the PO Engineer before concrete beds are laid. The
CO(s) shall give further notice in writing when concrete beds have been laid and these must also be
inspected and approved by the PO Engineer. No drainage trenches shall be filled or drains covered up
until they have been inspected, properly tested, and finally approved by the PO Engineer, or until the
dimensions of trenches, etc., have been checked and agreed upon by the CO(s) and the PO Engineer.
5.10.1.6 Flashing
Pipes passing through roofs shall be flashed using lead or copper flashing with an adjustable integral
flange of adequate size to extend not less than 200 mm from the pipe in all directions and flashed into
the roofing to provide a watertight seal.
Sanitary vent stacks through corrugated asbestos roofing shall be installed to be watertight to the
details shown, with a PVC reducing socket, copper flashing and cement mortar.
5.10.1.7 Traps
Each fixture and piece of equipment having an integral trap or seal, requiring connections to the sanitary
drainage System shall be equipped with a trap. Each trap shall be placed as near the fixture as possible,
and no fixture shall be double trapped. Traps installed on PVC pipe shall be PVC. Traps installed on
lavatory wastes shall be brass recess‐drainage pattern, or brass‐tube type, chrome plated.
5.10.1.8 Floor drains
Floor drains shall have cast iron bodies with double drainage flange, weep holes and bottom outlet.
Outlet shall be inside caulked or screwed.
Toilet room drains shall have adjustable chrome plated brass strainers with free strainer area not less
than one and one half times the connecting pipe size.
Pump room, equipment room and area drains shall have anti‐tilting slotted cast iron grates of not less
than 150 mm diameter.
5.10.1.9 Downspouts and clutters
Downspouts for roof drainage shall have a diameter not less than 100 mm and shall be fabricated of
light gouge galvanized steel or PVC. All offsets and bends shall be made with 451‐bends and no skewed
joints or bowed down spouts will be permitted. Downspouts shall be supported with galvanized steel
straps or PVC Straps.
Clutters shall have half round or rectangular profiles in PVC or galvanized iron. The width or diameter of
gutters shall be 150 mm.
Renewable Energy Guidelines Nov. 2013 67
Volume 12 Civil Works
5.10.2 Water supply
The internal water supply system shall be designed entirely by the CO(s) using water from the
penstocks. Provision shall be made for the following additional supply points:
One hydrant (d = 75 mm) for firefighting / cleaning / gardening next to the surfaced parking area
One outdoor water tap next to the main entrance door
Water pipe and fittings within structures shall be of galvanized mild steel (GI) and water piping in the
ground shall be either of PE or PVC.
5.10.2.1 Water pipes, fittings and connections
The piping shall be extended to all fixtures, outlets, and equipment. The water piping system shall be
installed so as to be drained. Drainage shall be accomplished using 12 mm plugged or capped fittings at
each low point, except where a drain valve or a hose tap is reasonable.
Pipe shall be cut accurately to measurements established at the power house and shall be worked into
place without springing or forcing. Care shall be taken not to weaken structural portions of the building.
Pipes, valves and fittings shall be kept in a sufficient distance from other work and other pipes to permit
not less than 25 mm between pipes and other work. No water pipe shall be buried in floors or cast in
concrete walls, unless specifically indicated or approved. Changes in pipe sizes shall be made with
fittings. Installation of pipe and fittings shall be made in accordance with the manufacturer's
recommendations. Testing and sterilization of sanitary System
Sanitary, waste, vent and water piping shall be tested and approved before acceptance. Underground
sanitary and waste piping shall be tested before backfilling.
5.10.2.2 Drainage and venting system
Piping shall be tested with water before the fixtures are installed. After the plumbing fixtures have been
set and their traps filled with water, the entire drainage and venting System shall be tested.
5.10.2.3 Cleaning and adjusting
Equipment, pipes, valves, fittings, fixtures and appurtenances shall be cleaned of grease, metal cuttings,
and sludge that may have accumulated from Operation of the system during the test. Any stoppage,
discoloration or other damage to the finish, furnishings, or parts of the building, due to the CO's failure
to properly clean the piping system, shall be repaired by the CO. Flush valves and automatic control
devices shall be adjusted for proper Operation.
5.11 Painting
5.11.1 General
This specification covers the general requirements and standards of workmanship and the painting and
protective coatings required to be carried out by the CO(s) of the works.
No alternative or substitute painting standard or specification will be accepted unless it is specifically
required for the above stated reason. No painting or protective coating will be accepted by the PO
Engineer unless it is at least to the standard and of the quality specified herein.
68 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
5.11.2 Appropriate standards
Where no explicit instruction is given standards in the Specification or by the manufacturer concerning
any particular aspect of the workmanship, materials or procedures in connection with anti‐corrosion
protective Systems in the works for iron and steel structures, the relevant recommendations of the
following Standard or code of practice shall apply:
DIN 50900 Corrosion of metal
DIN 50928 Protective coating of iron and steel structures against corrosion
DIN 18364 Surface protection of steel structures
DIN 50976 Hot‐dip galvanized coatings on iron and steel articles
DIN 8565
DIN 8567
Sprayed metal coatings
5.11.3 Local conditions
All coatings shall be suitable for the long term protection of the plant under operational conditions at
the site of installation. The CO's attention is specifically drawn to the extremes of temperature and
humidity recorded in the region and he shall take into account possible abrasions, restricted Ventilation,
and the various potentially corrosive environments within the works buildings and structures.
5.11.4 Decorative finish and final appearance
The CO(s) is advised that internal civil works finishes, furnishings and decorative colour schemes in the
main operational areas should be of a pleasing appearance, coordinated and designed to produce a
comfortable working environment. Accordingly, the CO(s) shall allow for consultation with the PO
Engineer regarding the final color scheme and decoration of the works.
5.11.5 Trial areas and sample pieces
Prior to the commencement of the site, painting work designated area(s) or section(s) of the works shall
be completely painted as a sample of the work and workmanship to be carried out. The area(s) or
section(s) shall include complete samples of all the major painting required in the works.
The area(s) shall be offered for review by the PO Engineer and shall, upon approval, be then preserved
as a reference Standard for the work.
No extra payment will be made for carrying out such protection or decoration in advance of the general
work, or for the removal and repetition or improvement of the work if required by the PO Engineer in
order to achieve the specified Standard.
5.11.6 Precautions etc.
All surface fittings, ironmongery, etc., except hinges shall be removed before painting and refixed on
completion. They shall be entirely free of any droppings, paint smears and blemishes. Labels, pump and
other machinery name plates, data plates, markings, etc., shall not be over painted but carefully
preserved by removal and replacement or by masking.
Renewable Energy Guidelines Nov. 2013 69
Volume 12 Civil Works
The CO(s) shall pay particular attention to the toxicity, inflamability and the explosive dangers related to
the storage and application of the Systems and shall take all precautions necessary to the satisfaction of
the PO Engineer to protect his operatives, the public and other site personnel.
5.11.7 Work succession
No one‐site coat may proceed in any section of the works until the entire section is complete and the PO
Engineer has had notice of completion in order that he may inspect the work and authorize the
application of subsequent coats. Each successive coat shall preferably be of different colour or shade to
facilitate inspection. The PO Engineer may apply his own identification markings on undercoats to
ensure full compliance with the Specification.
5.11.8 Application of Protective Coating and Paint
Unless specifically specified elsewhere, the protective cover shall be applied in accordance with the
manufacturer's instructions to the full thickness range specified, particular note being taken of the
requirements for the time interval between successive coats of the cover.
The coating thickness for painting on concrete or plaster surfaces shall be in accordance with the
manufacturer's instructions or proposals.
5.11.9 Equipment and condition
Brushes, tools and equipment shall be kept in a neat and clean condition. Painting shall not be carried
out in the vicinity of other operations which might cause dust. The final coat shall be uniform in colour
and free from brush marks, runs or other defects.
5.11.10 Paint thickness and continuity
The CO(s) shall provide and maintain, during manufacture and on site, gauges and measuring equipment
of an approved type to ensure that the specified film thickness are achieved, paint holidays are avoided,
and adhesion is to the satisfaction of the PO Engineer.
Wet film thickness gauges shall be provided to and used by each painter to check the rate of paint
application.
The thickness of the built‐up dry film after each paint coat applied to steel or other magnetic surfaces
shall be measured systematically with a dry film thickness gauge.
The sweep voltage on high voltage DC equipment shall not exceed half the voltage required to spark
through the complete paint system specified.
The following Instruments, with the manufacturer's operating instructions, shall be provided,
maintained and used by the CO's inspector. In addition, under the Contract a separate set shall be
provided and maintained for the Engineer's sole use for the duration of the TOP Agreement:
1 adhesion tester, cover 0 to 280 kg/ cm²;
1 DC high voltage detector, 20 kV, with rechargeable batteries;
1 paint inspection gauge, 0 to 500 microns;
4 "wetcheck" moisture meters with suitable concrete and timber scales;
1 dry film thickness gauge, 0 to 500 microns;
4 wet film gauges, up to 500 microns;
1 steel temperature gauge, up to 50°C;
70 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
1 air humidity gauge;
1 air Thermometer (maximum and minimum);
surface profile gauge, up to 150 microns.
Daily checks shall be carried out and recorded on site in accordance with the provisions of DIN 55928.
5.11.11 Dry film thickness
References in the Specification to dry film thickness (OFT) shall mean the minimum dry film thickness
measured with a suitable Instrument, either of individual coats, or the total System, as specified in
microns (flm). The maximum permissible coat tolerance shall be + 15%, ‐ 0% over the OFT.
5.11.12 Paint source and supervision
All paint shall be "new" and "fresh" and obtained from approved manufacturer(s). If so directed by the
PO Engineer, the CO(s) shall ask the paint manufacturer(s) to spot‐check the preparation and painting
and submit to the PO Engineer and the CO(s) a written report on his observations.
5.11.13 Systems to be compatible and complete
All coatings, stoppings, primers, compatible and undercoats and finishing paints of any one complete
protective system shall be compatible with each other and the completed system shall provide
continuous, pore‐free coatings resistant to physical and chemical disintegration in the environment in
which they are to be used.
As far as is practicable, materials, forming any one protective and/or decorative System used in the
permanent works, shall be obtained from one manufacturer.
5.11.14 Bitumen coating
Bitumen coatings shall be to DIN 18195, 18336 and DIN 18337. Suitable grades shall be selected where
the coating will be in contact with potable water.
5.11.15 Identification
All paint shall be supplied in sealed Containers bearing the following information in addition to any
statutory requirements:
Manufacturer's name, Initials or trade mark;
Whether priming, undercoat or finishing coat;
Whether for interior or external use;
The colour reference number;
The method of application (e.g. brush);
The batch number and date of manufacture of re‐test
The shelf life of the contents.
Containers for materials other than paints shall bear as much of the above information as appropriate.
5.11.16 Storage and use of paint, thinners etc.
Paint, thinners etc., shall be stored in sealed Containers in a lock‐up store at a temperature of not less
than 4°C and not more than 27°C. Any special storage conditions for the paint recommended by the
manufacturer shall be observed.
Renewable Energy Guidelines Nov. 2013 71
Volume 12 Civil Works
5.11.17 Paint preparation
Paint shall be supplied from the CO's paint store to the painters ready for application. Any addition of
thinners shall be made in the store under supervision and up to the limit detailed on the appropriate
manufacturer's paint data sheet for the particular method and conditions of applications concerned.
5.11.18 Waste
The CO(s) shall provide on site suitable moveable receptacles into which are to be placed all the liquid,
slops, washings, etc. All solid refuse or inflammable residues shall be removed from site or carefully
burned. No refuse shall be deposited on any soil or disposed down any permanent sanitary fittings, sinks
or drains. The CO(s) shall immediately clean up any unauthorized deposition and remove from the site
any employee found to be responsible.
5.11.19 Spray application
The equipment to be used for spray application shall be in strict accordance with the paint
manufacturer's instructions for each coating material. Any runs shall be immediately brushed out.
5.11.20 Brush application
The shape and quality of the brushes shall be suitable for the work to be carried out. Extension handles
to brushes shall not be permitted.
5.11.21 Metal coatings
All steelwork (except roof structures) where ever installed and if not specified otherwise shall be coated
by appropriate measures for corrosion protection.
Metal coatings required for protective purposes on any item of metalwork shall be applied after
fabrication of the items is completed, including all punching, welding, drilling, grinding, screw tapping
and cutting, and after the removal of surface defects. Tapped holes shall be blanked off before the
metal coating is applied.
5.11.22 Prefabrication primers
Unless otherwise specified, prefabrication primers for steelwork shall comply with the relevant DIN
Standards and contain corrosion‐inhibiting pigments, adhere firmly to the Substrate and form suitable
bases for the succeeding coats in the protective paint System.
5.11.23 Surface Preparation by blasting
All surfaces to be coated shall be free of scale, rust, grease, oil, dust and other deleterious materials. The
surface finish of blast cleaned steel shall be in accordance with the relevant DIN Standard and to a visual
standard in accordance with SIS 05 59 00 at the time of painting. The blast profile shall be within the
limits 50 ‐ 75 microns.
Abrasives shall be restricted to reusable iron or steel (grit and shot) or copper slag. The type and grades
of abrasive shall be selected in accordance with the appropriate DIN standard.
Within four hours of completion of surface preparation, and before surface re‐rusting occurs, a coating
of primer shall be applied to avoid deterioration of the prepared base metal. No contamination shall be
permitted to occur between blast cleaning and primer coating.
72 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
5.11.24 Dehumidification required for special purposes
The CO(s) shall supply and operate such dehumidification equipment as may be necessary to preserve
blast cleaned surfaces in a pristine condition until they can be coated and/or to provide the curing
conditions necessary for such coats.
5.11.25 Uncoated surfaces
The only surfaces of iron or steelwork or non‐corrosion resistant materials, which are to be left
unprotected by paint or metal coating are:
The internal surfaces of boxes or hollow sections which are of dimensions too small to permit access for painting either at the fabrication stage or for maintenance during the operation life of the steelwork and which are to be hermetically sealed by welding;
Those surfaces of built‐in iron or steel members which are to have concrete cast against them;
Machine bright parts and bearing surfaces which shall be thoroughly cleaned, polished and protected from corrosion by painting with one coat of a mixture of white lead and tallow or other similar approved material before dispatch. The CO(s) shall provide solvent for removing the treatment;
Parts which are specified to include corrosion allowances instead of protective coatings.
Stainless steel parts
Surfaces of iron or steel members, which are to have concrete cast against them shall be clean and free
of deleterious matter and loose rust at the time of concreting. The paint protection system, to be
applied to the permanently exposed faces of these members before the members are built in, shall be
continued for 50 mm as marginal strip along the contact surface. No paint containing Aluminum in me‐
tallic form shall be allowed to come into direct contact with the concrete.
5.11.26 Repair of damaged work
Unless specified elsewhere, areas of paint on steelwork, which have been damaged shall be cleaned to
sound material and the edges of the undamaged paint smoothed with sand‐paper to a gentle bevel. The
specified paint system shall then be applied in accordance with manufacturer's instructions to bring the
damaged area up to the same state of protection as the surrounding paintwork, with each coat of new
paint overlapping the corresponding existing coat of paint by at last 50 mm.
Where epoxy coatings are damaged, suitable repair supplied by the manufacturer of the original coating
shall be applied in accordance with the manufacturer's instructions.
5.11.27 Fastenings
Bolts, nuts and washers and other demountable fastenings of all galvanized parts and also Aluminum
alloy parts shall be in stainless steel to the appropriate DIN Standard and shall remain unpainted.
P.T.F.E. washers shall be fitted beneath bolt‐head and washer when fastening galvanized and aluminum
alloy parts.
Fastenings, except high tensile, of all ferrous parts shall be steel prepared and galvanized to the relevant
DIN Standards, primed and painted in accordance with location.
Unless specifically approved and required for superior protection, electro‐galvanizing, nickel, cadmium
or any other plating process, except chromium plating, will not be acceptable, and shall not be offered.
Renewable Energy Guidelines Nov. 2013 73
Volume 12 Civil Works
5.11.28 Painting and protection of bolted connections
Joints areas of bolted connections shall be masked to maintain the surfaces free from any paint applied
prior to making the connections. Masking shall be removed before erection.
After Installation and after all bolts have been tightened, the area of the connection shall be cleaned to
remove all dirt, dust, oil or other contaminant. Particular care shall be taken to ensure that all traces of
oil and grease are removed from bolts, nuts and washers.
Bolts, nuts and washers and any exposed at bolted connections shall also be primed as specified,
particular care being taken to ensure that any crevices are fully sealed. The remaining coats of the paint
system shall then be applied.
5.11.29 Plaster and concrete protection
Where specified or required for the protection of the work or the containment or storage of chemical
solutions, concrete or rendered surfaces shall be protected with paint systems accordingly to the table
at the end of this section.
5.11.29.1 Preparation of concrete and rendered surfaces
Concrete and rendered surfaces shall be thoroughly cured in accordance to the manufacturer's
instructions before the application of any painting system is started.
5.11.29.2 Minimum thickness for painting of concrete and plaster
The total dry film thickness of any used paint system shall have a minimum value of tests for 1 mm. In
order to restore the coating integrity and plaster thickness whenever the paint inspection gauge is used
or wherever the coating has been otherwise damaged, the surface shall be abraded for 50 mm around
such damage and the area touched in with not less than two thick applications.
5.11.29.3 Preparation of plaster, brickwork and concrete surfaces
Efflorescence present on the surface of internal plaster, brickwork and concrete shall be removed by
scraping and brushing before any surface paint is applied. When fluorescence has been removed
surfaces shall be left for at least three days before priming. Painting shall be deferred where further salt
deposits form on the surface during this period.
Plaster surfaces to be painted shall be cleaned down, smoothed as necessary, and all cracks shall be
filled with stopping for plaster. All fittings shall be carried out before paint is applied to the surface.
Brickwork, block work and concrete surfaces shall be cleaned of all contaminating matter before being
primed. Subject to the approval of the PO Engineer large holes which would cause a break in the paint
film shall be filled with mortar, the surface being rubbed down to match the surrounding areas.
5.11.29.4 Preparation of wood surfaces
Wood surfaces shall not be painted when the moisture content of the timber measured with an electric
moisture meter exceeds 12% for interior surfaces and 18% for exterior surfaces.
Hardwoods and soft woods for which a clear finish is specified shall be rubbed down with abrasive paper
to give a smooth surface which shall be free from contaminating substances, scratches and other
imperfections.
74 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
Prior to coating all nail and screw holes, etc., shall first be stopped. Surfaces which are to be painted
shall be rubbed down to remove all contaminating substances and imperfections which would be visible
in the finished paint film. The surfaces of knots and resinous streaks shall then be painted with two
coasts of knotting, the first being allowed to dry before the second is applied.
The surfaces of timber treated with a water‐borne preservative by an impregnation process shall be
rubbed down and dry brushed to remove all traced of efflorescence before the primer is applied. Where
surfaces are suspected of being infected with mould they shall be thoroughly treated with a fungicide.
5.11.29.5 Final treatment of wood, plaster, etc.
The final painting System required in the works is given in the following table and is presented to
Tenderers for guidance to include such work in their supply under this Contract.
5.11.29.6 Paint system for plaster and concrete protection
Surface Environment Primer Final Treatment
Concrete and cement plaster
High humidity 1 coat of a highly weather resistant resin, thinned to manufacturer's instruction
2 coat of a highly weather resistant synthetic resin based paint
Concrete Exposed to oil 1 coat with a plastic modified hydraulic mortar
3 coats with an oil resistant synthetic resin based paint
Concrete Exposed to mechanical and chemical attack
1 coat of colorless 2‐pack epoxy‐based paint, thinned to manufacturer's instructions
2 coats of a 2‐pack epoxy‐based paint
Concrete flooring Exposed to mechanical wear and oil
1 coat of colorless rubber‐based paint, thinned to manufacturer's instructions
2 coats of a 2‐pack epoxy‐based paint
Internal concrete and plastered walls
Exposed to minor abrasion 3 coats of an oil‐free synthetic resin‐based dust‐binding paint
Concrete flooring Exposed to minor mechanical wear
2 coats of an oil‐free synthetic resin‐based dust‐binding paint
Internal plastered Exposed to normal conditions
1 coat of polyvinyl‐acetate dispersion type, non‐chaking, thinned to manufacturer's instructions
2 coats of polyvinyl‐acetate dispersion type, non‐chalking
Source: Own compilations
Renewable Energy Guidelines Nov. 2013 75
Volume 12 Civil Works
5.12 Electrical works
5.12.1 Scope
All electric installations for power production and control of generating equipment, A/C high/medium
voltage as well as DC circuits will be designed and installed, including all cabling, protection and
switchboards by the E&M contractor.
The scope of work of this Contract are design and construction of all internal lighting and 230 V
electricity distribution systems, lightning protection and basic earthing system. The take off point and
connection location to the LV will be indicated by the E&M Contractor. The Contractor shall include in
his building construction design and works all channels and recesses that are required by the E&M
Contractor for laying his respective cable network.
The layout of the electric internal wiring shall require the approval of the PO Engineer.
5.12.2 Cables and joints
Each circuit shall be equipped with copper or Aluminium core cable of adequate dimension or as shown
on the Drawings and have standard sheathed PVC insulation able to resist moisture and shall be
watertight.
Where single core cables are used, cables of different colors shall be used for different phases and the
neutral cable (red, yellow and blue for the phase wires and black for the neutral wire). The earthing
cable shall be of green color.
All joints shall be minimized as far as possible and they shall be well constructed. They shall be capable
of withstanding ambient conditions to provide uninterrupted power supply and be free from danger.
Cable shall be supported on cable trays or laid in ducts as shown on the Drawings. All ducts and trays
shall be earthed.
5.13 Permanent buildings
Provision shall be made in each room for electric lighting and power sockets as shown on the Drawings.
The whole system including earthing arrangements shall be subject to inspection and approved by the
PO Engineer.
An MCB sub distribution board with a Maintain isolating switch and a breaker for each circuit will be
provided inside the building.
5.13.1 Wiring system and earthing
Cables are to run in one length without splicing. Exceptions require the approval of the engineer. Each
circuit shall be protected by appropriate cut‐off fuses of 10, 16 or 25 A. The wiring shall be laid in in‐wall
conduits.
The voltage drop between the feed‐in and the electrical consumer shall not exceed 3% of the nominal
values.
For the final dimensioning of the conductor cross sections and the corresponding fuse, the DIN/VDE
0100 and the DIN/VDE‐0298 standards are valid. The cross section design is to be effected in accordance
to DIN/VDE. The lines have to be provided with 20% reserve to the nominal current. In main circuits the
76 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
smallest allowed cross section is 2.5 mm2. Control and measuring circuits will be wired according to the
back‐up fuse, whereby 0.75 mm2 is accepted as smallest section. For electronic circuits, the wiring in
form and method is depending on the conditions of the manufacturer, however with a minimum of
0.75 mm². Measuring circuits are to be installed shielded. The wiring of the control‐, signal and
measuring circuits as well as electronics in‐/outputs is done in colour. N‐conductors shall be marked
blue, PE‐conductors green‐yellow.
The control room will be equipped with an air conditioning system, the wiring and protection shall allow
for the increased load on the cables.
All terminal‐, plug‐in‐ and solder tag strips are to be assembled with a 20% reserve. The CO(s) has to
ensure a durable protection against corrosion for the internal wiring.
An appropriate earthing system is to be designed and laid by the PO and CO(s). Foundation earths,
ground strips and, if necessary, earth rods have to be provided. The effectiveness of foundation earths
supposes that a certain degree of humidity is kept in the ambient concrete. Therefore, it is not allowed
to apply humidity insulation under foundation earth. Earth termination network and protective earthing
have to be constructed as different systems. The earthing resistance shall be 2 Ohm. The required
earthing conductor size is compiled in following table.
Table 5‐1: Earthing conductor size
Equipment Buried conductor Conductor above ground & in trenches
Main station grid 40 mm dia MS rod 65x8 mm GS flat
Switchgear ‐‐ 65x8 mm GS flat
400 V distribution boards ‐‐ 50x6 mm GS flat
HT motors ‐‐ 50x6 mm GS flat
LT motors above 125 kW ‐‐ 50x6 mm GS flat
LT motors ‐ 25 to 125 kW ‐‐ 25x6 mm GS flat
LT motors – 1 to 25 kW ‐‐ 25x3 mm GS flat
Fractional HP LT motors ‐‐ 8 SWG GS wire
Control panel & control desk ‐‐ 25x3 mm GS flat
Push button stn. & Junction box ‐‐ 8 SWG GS wire
Cable trays, cols. & structures ‐‐ 50x6 mm GS flat
Rails & other metal parts ‐‐ 25x6 mm GS flat
Equipment earthing for switchyard ‐‐ 76x8 mm GS flat and 50x6 mm GS flat
Source: Own compilations
The power house shall be equipped with a lightning protection system. On the roofs air terminations are
to be installed. The wiring shall be laid in in‐wall conduits.
Renewable Energy Guidelines Nov. 2013 77
Volume 12 Civil Works
5.13.2 Light fixtures and power outlets
Each room shall be equipped with at least on fluorescent tube light fixture and two wall outlets.
The machine hall shall be equipped with fluorescent tube light fixtures at a level of +2.5 m and in
horizontal distances of 3 m. Each two light fixtures shall be switched individually.
The powerhouse entrance shall be equipped with high beam lights, mounted at level +3 m. All gate
operation positions shall also be equipped with high beam lights, mounted on appropriate poles where
necessary.
78 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
6 Roads and Pavements
6.1 Formation and sub‐grade
Formations means the surface of the soil in cut or fill after completion of earth works on which further
road work construction is carried out. Sub‐grade means the soil immediately below the formation.
The formation and sub‐grade shall be graded and compacted to the levels such that the dry density of
the upper 15 cm of the ground or fill is not less than 95% of the maximum dry density determined by
tests in accordance with DIN 18127.
Where existing ground conditions are such that direct compaction of the sub‐grade according to the
specification is impossible unsuitable material shall be removed and replaced with suitable granular sub‐
base.
Where the sub‐grade is in natural ground, the compaction shall, whenever possible, be carried out at or
near to the natural moisture content of the ground. The formation shall be kept free of standing water
at all times and drains shall be provided so that it will drain quickly and effectively during rain.
Any irregularities or depressions that develop during compaction of the sub‐grade or any area which
becomes muddy, broken‐up or loosened due to weather conditions shall be corrected by loosening the
surface of these places and adding, removing or replacing these materials and re‐compacting so that the
surface is smooth and uniform.
6.2 Sub‐base and road base
The sub‐base and road base shall be graded and compacted to the required levels densities as required.
The materials for the sub‐base and road base shall be laid in layers, each not exceeding 15 cm or being
less than 7.5 cm. The total compacted thickness of subbase and road base shall nowhere be less than
the specified nominal thickness. If not otherwise directed, the sub‐base and base in roads shall have
each a thickness of 20 cm, in footpaths a thickness of 15 cm.
The sub‐base and road base materials shall be deposited in such a manner that there is no segregation
and the materials require the minimum of blading or spreading. Each layer of material shall be
compacted immediately after spreading.
If any of the sub‐grade material is worked into the sub‐base material during spreading, blading or
compaction, all the sub‐base material in the affected area shall be replaced by fresh sub‐base material.
On completion of compaction and before commencing the next Operation, the surface of the granular
sub‐base and road base shall comply with a surface tolerance of+/‐1 cm.
6.3 Sealing of surfaces
Wherever possible, the operations of final trimming of the formation, compaction of the sub‐grade and
placing and compaction of the granular sub‐base and road‐base shall be carried out without delays.
The CO(s) shall be responsible for taking all necessary steps to prevent damage to the previously
completed layer or layers by excessive wetting or drying out due to weather conditions or by traffic or
any other cause. If the contractor considers it as advisable or if so ordered by the PO Engineer, the
completed layers shall be sealed using bitumen road emulsions.
Renewable Energy Guidelines Nov. 2013 79
Volume 12 Civil Works
In any case, the completed surface of the road base shall be sealed with suitable emulsion (MC70) at a
rate of 1.5‐2.0 kg/m² immediately when it has been completed and checked for compliance with the
specified tolerances.
6.4 Bituminous road surfaces
Unless otherwise specified or detailed, materials for flexible road surfacing shall be bituminous concrete
and asphalt. The surface on which each course of coated bituminous material to be laid shall be free
from standing water and any loose or deterious material and shall be tested for accuracy.
Before laying commences in any area, a tack coat of bitumen road emulsion shall be applied to the
whole area of the preceding course and any other surfaces with which the coat will be in contact. After
cleaning, the top of the base should be sprayed with suitable emulsion (MC70) at a rate of 1.5‐
2.0 kg/m²; the surface of the bituminous coat should be treated with asphalt tack coat (RC250) at a rate
of 0.5 kg/m². The emulsion shall be allowed to break completely before the subsequent bituminous
layer is laid on it.
Coated macadam material shall be delivered to site in clean vehicles and shall be protected to minimize
loss of heat in transit and against contamination by dust or other deleterious matter. The rate of
delivery to the site shall be regulated so as to enable the material to be laid with the minimum of delay
and so that the paver can operate continuously.
The coated thickness of individual layers shall be not less than the minimum compacted thickness
specified or shown on the approved drawings. If not otherwise directed, the bituminous wearing course
shall have a thickness of 10 cm, the asphalt course 5.0 cm.
In case of bituminous roads to be reconstructed, the CO(s) has to reinstate all asphalt courses according
to their original thickness.
80 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
7 Metalwork and steel structures
7.1 Scope
This section sets out the general requirements for the engineering metalwork and steel structures re‐
quired in the works.
7.2 General
Applicable standards for the steel structures are DIN 17100, EN 10025, DIN 50976, DIN 50115, DIN
50125, DIN 50111 or equivalent. The permissible design stresses for materials, bolts, rivets, etc., are
given in DIN 18800, for welds in DIN 4100. Rolled structural steel sections shall be mild steel, conforming
to DIN 17100. The dimensions, tolerances and properties of the structural sections shall conform to DIN
18201 up to 18203 and to DIN 18800. Where the use of prefabricated proprietary designs is proposed,
the standards to which they are manufactures shall be no less rigorous than specified herein. For
structural steel work assemblies, steel bolts, nuts and washers shall be high strength friction grip bolts
conforming to DIN 6914 up to DIN 6916 or black bolts including nuts and washers conforming to DIN
7989 and DIN 7990. All welding consumables (electrodes, wire, filler rods, flux, shielding gas and the
like) shall comply with the requirements of the appropriate standard and with the requirements of the
appropriate welding procedure. All steel structures shall be either of the lattice type or shall be made of
prefabricated structural steel members to be mounted and assembled on site.
All members of structures shall be of structural steel St 37.2.
7.3 Design and detailing
The CO(s) shall structurally design and construct all steel/metal plant and equipment except for the
hydro‐electric generation machinery of the power station.
Structures and components shall be shop‐fabricated so as to form sub‐assemblies of the largest practical
size suitable for transportation, handling and erection. Detailing and design should be in accordance
with DIN 18800.
7.4 Welding and heat treatment
All welding carried out during fabrication in the factory and erection on the Site shall be carried out in
accordance with the requirements as shown on the approved detail drawings prepared by the CO(s).
Details of the proposed welding procedures shall be submitted to the PO Engineer for approval at the
same time as the detail drawings. All connections shall be welded in such a manner as to make the fin‐
ished connections neat and smooth in appearance, and suitable for painting. All slag shall be removed,
and any sharp projections shall be ground smooth. All welding carried out during fabrication in the
factory and erection on the site shall be carried out in accordance with the requirements of DIN 4100
and as shown on the approved detail drawings. Before welding is commenced either in the fabrication
shop or on site, weld procedure tests shall be carried out where directed by the PO Engineer.
All welders employed either in the fabrication shop or on site shall pass qualification tests relevant to
the weld procedures in use in accordance with the appropriate standard. Welders shall have satisfactory
evidence of having been engaged in welding for at least 9 months in the preceding period.
Renewable Energy Guidelines Nov. 2013 81
Volume 12 Civil Works
When not otherwise specified, welds shall be subject to non‐destructive testing by processes which may
include but not necessarily be limited to radiographic, ultrasonic, magnetic particle, or dye penetration
methods, depending on the type of weld and its Position in the structure. About 50% of all welding shall
be tested.
If any work shows defects or fails to comply with the requirements of the approved drawings or the
specification for any reason, it shall be repaired or rejected, even though it may have been carried out
by qualified welders using approved procedures. The welding procedure for cupro‐nickel linings shall
avoid porosity in the weld and any uncontrolled dilution of the weld by iron picked up from the steel.
Special precautions shall be taken to avoid lamellar tearing when welding thick plates and low hydrogen
content electrodes shall be used. Class 1 welds shall be fully radiographed except where otherwise
specified.
In bad weather, additional measures are needed in the course of welding consequently, in case of rainy
weather, Provision shall be made to keep the places of welding dry. In weather with temperatures
below 5C°, a Strip of 100 mm should be preheated to 50C°, on both sides of the welded joint in case of
both seams and tack welds.
Splash, burning‐in, uneven are, oversized root edges at corner joints, unsatisfactory seam or any crack
are impermissible in the course of welding. Surfaces should be free from any marks of impact,
indentation and deformation.
Welding on galvanized steelwork and over zinc primers or paint shall not be permitted.
7.5 Flooring
Flooring shall be fabricated from chequer plate or open mesh panels.
All steelworks for chequer plates, frames or open mesh flooring shall be constructed in mild steel and
shall be hot‐dip galvanized after manufacture, except where otherwise specified.
For all prefabricated metalwork, as chequer plates, frames, open mesh and the like, the CO(s) shall
submit fabrication drawings for the approval of the PO Engineer prior to the manufacture of any of
these items. Flooring and supports thereto shall be designed and manufactured to resist a uniform
applied live loading of 7.5 kN/m² unless otherwise specified. Flooring panels shall generally be
removable by one man and the maximum weight of each panel shall not exceed 25 kg. Removable
sections of flooring shall be provided with holes for lifting keys, keys to suit for each location, and be ar‐
ranged to permit removal without disturbance to Support brackets, spindles, pipe‐work, etc.
Intermediate support members shall be provided as required and attached to the supporting structure.
Flooring shall be detailed and fabricated so that no cutting is required on site. Supporting steelwork shall
comply with the requirements of clauses for structural steelwork. Bolt holes in brackets and mountings
shall be slotted to allow for adjustment of line and level. Mild steel continuous kerbing shall be provided
for seating the flooring in concrete. Kerbing and other supporting structures for building into concrete
shall have lugs welded on a maximum spacing of 600 mm. Flooring shall be secured to the kerbing or
supports by stainless steel flush screws. The width of any access walkway shall be not less than 750 mm.
Floor plating over openings in concrete or brickwork shall be set flush in mild steel framed kerbing
provided with adequate integral lugs for building in. Plating and frames shall be heavily galvanized or
Aluminum alloy. Floor plating shall have a raised pattern.
Open mesh flooring panels shall be fabricated from mild steel load bearing bars of flat section backed
with round, square, or twisted bars perpendicular to and welded to each load bearing bar. Panels shall
82 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
be trimmed across the ends of load bearing bars by flats of the same cross section welded to each load
bearing bar. Cut‐outs for plant items shall be trimmed with curved or straight edge trimming as
appropriate. Panels shall be fixed to the kerbing or supporting steelwork with adequate flush stainless
steel screws or clips so that movement is prevented.
For metalwork at floor level joints differences between flooring sections and between steel flooring and
adjacent concrete shall be:
difference in level at joints: 3 mm
joint gap: 3 mm.
7.6 Handrailing
Unless otherwise specified all rails shall be fabricated from 32 mm bore galvanized medium weight steel
tube. Hand railing shall be provided along every edge of all metalwork and concrete walkways, stairs or
accessible open areas where the drop beyond the edge exceeds 700 mm. Hand railing shall consist of
Standards at regular intervals not exceeding 1.5 m, and two rails. The upper rail shall be 1.0 m above the
adjacent finished floor level, and 900 mm above the nosing line on stairways. The lowest rail shall be
midway between floor and upper rail. The hand railing fixing and anchorages shall be designed to
withstand a continuous horizontal load at the top rail of 750 N/m. Hand railing shall be flush jointed.
Hand railing terminating against a wall shall have a suitable wall fixing.
Where required ladders, stairways or other openings shall be guarded on three sides by hand railing
conforming to the requirements stated above. Access to the ladders or openings shall be guarded by
two removable galvanized hanging chains secured to eyes at top and middle levels. Hand railing shall be
of uniform appearance and manufacture.
7.7 Laddering and stairways
Stairs shall have an inclination of approximately 30°. They shall be complete with handrails, min. 100 cm
vertical height.
All ladders are to have a minimum width of 750 mm where practicable. Vertical ladders shall be installed
alternating left hand/right hand side to horizontal platforms placed approximately every 6 m of vertical
height. Vertical ladders of more than 3 m height shall be provided with safety hoops at intervals not
exceeding 900 mm, with the lowest hoop 2.0 m above the ladder foot. Load assumptions for ordinary
platforms shall be:
for platforms used by personnel and for support of light equipment with single weights of less than 50 kg 2.5 kN /m²
for all other platforms 7.5 kN /m² unless otherwise specified or stipulated in the applicable Standards.
With exception of internal access ladders to water tanks, reservoirs and wet sumps, laddering shall be in
steel (fully hot‐dip galvanized). Ladders for internal access shall be in stainless steel. Generally all ladders
shall be in accordance with DIN 3620.
The stringers shall be sized to suit the height of the ladder and the interval of the stringer supports.
Stringer shall be radiused over the top and drilled to receive the rungs, which shall be welded to the
stringers on each side of each stringer. The bottom ends of the stringers shall not be designed for floor
fixing, but shall terminate at wall fixing supports at least 150 mm above the floor. All edges of stringers
shall be ground smooth to remove burrs and sharp edges.
Renewable Energy Guidelines Nov. 2013 83
Volume 12 Civil Works
Stairways shall be designed for a loading of 7.5 kN/m² of plan area of the stairway. Steel stairways shall
be provided with tubular hand railing, stringers of cross section suitable for the span and loading, and
treads of open mesh flooring or chequer plating. Except where specified otherwise, the rise between
treads shall be uniform and between 150 mm and 175 m. Stairways in the same area of the works and in
similar locations shall have the same angle and height of rise between treads.
The width of the treads shall be between 250 mm and 300 mm. The width of the stairways shall not be
less than 750 mm.
The stringer shall be mounted by means of angle brackets with slotted holes for adjustment of line and
level.
7.8 Miscellaneous
7.8.1 Dissimilar metals
The use of dissimilar metals in contact, liable to lead to galvanic action, shall be avoided where possible.
Mild steel surfaces to be in contact with aluminum or aluminum alloy shall be deemed to satisfy this
requirement if they are galvanized. For fixing aluminum to steel structures, bolts, nuts, washers and
screws shall be cadmium plated.
7.8.2 Opening tools
Lifting keys and devices for unfastening screws shall be galvanized mild steel and supplied at the rate of
one set for each five similar covers, with a minimum of two sets of each particular type.
7.8.3 Step irons
Step irons for buildings into pre‐cast concrete and step irons and handholds for building into the wall of
in‐situ concrete manholes and chambers shall be of round pattern. All step irons shall be cast iron with
rubber coating as corrosion protection. Step irons shall only be used where ladders would not be an
appropriate alternative.
7.9 Protection of metal surfaces of steel structures
7.9.1 General
Finished steel/metal surfaces shall be thoroughly cleaned of foreign matter. Finished surfaces of large
parts and other surfaces shall be protected with wooden pads or other suitable means. Unassembled
pins or bolts shall be oiled or greased and wrapped with moisture‐resistant paper or protected by other
approved means.
All ferrous metal work shall be provided with an effective painted or galvanized finish, applied in
accordance with the best practice to protect from corrosion.
The CO(s) shall submit for the PO Engineer's approval full details of the preparation, type of materials,
methods and sequences he proposes to use to comply with the requirements for the protection of the
works.
84 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
7.9.2 Painting/coating
7.9.2.1 Surface preparation
All surfaces to be painted shall be thoroughly cleaned by suitable means before application of paint.
After cleaning the surfaces shall be rinsed in a manner that no residues will remain.
For removing rust and mill scale on structural steel, piping and other steel surfaces, particularly parts
which will be in contact with water, exposed to heavy condensation and humidity or subjected to high
temperature shall be sandblasted (sandblasting SA 2.5) parts which cannot be sandblasted, shall be
cleaned of rust by power tool cleaning to the highest degree possible.
The sandblasted clean surfaces shall which are in contact with water receive a shop coat with a quick‐
drying highly pigmented 2‐pack zinc‐rich primer (e.g. Inertol R, 1000 µm each) and three final coats (e.g.
Inertol Poxitar F, 100 µm each), unless otherwise specified.
The sandblasted clean surfaces shall which are in contact with air receive a shop coat with a quick‐drying
highly pigmented 2‐pack zinc‐rich primer (e.g. Inertol R, 80 µm each) and one final coat (e.g. PVC‐single‐
layer lacquer, 80 µm), unless otherwise specified.
Primed surfaces contaminated with oil or grease shall be de‐greased in a manner not affecting the
quality of the primer. 2‐component coatings older than six (6) months shall be roughened prior to the
application of the next coat.
7.9.2.2 Application procedure
The most commonly used methods of application are painting by brush, roller, pressure and airless
spraying equipment. Selection of the application method depends on the surface to be painted. The
quality of the paint shall in no way be negatively influenced.
For all paints the surface temperature of the metal shall not be higher than +50C during the painting. Concerning special paints, the requirements set by the paint manufacturer shall be followed. All painting
shall be free of cracks and blisters and all runs shall be brushed out immediately. After application of the
last coat the paint system shall be free of pores.
Metallic parts, which are embedded in concrete, shall be painted with cement base paints.
7.9.2.3 Galvanizing
Unless otherwise specified, all fasteners and steel structures including ladders, platforms, hand rails and
the like and all exterior and interior steel surfaces of outdoor Works shall be hot‐dip galvanized or
electrolytic ally galvanized. For galvanizing, only original blast furnace raw zinc shall be applied, which
shall have a purity of 98.5%. The thickness of the zinc coat shall be:
For bolts and nuts of sizes above M36 approx. 60 micrometer and for sizes below M36 25 micrometer.
For all other parts, except for hydraulic steel structures or parts intermittently or permanently submerged in water, approx. 50 micrometer
For hydraulic steel structures or parts intermittently or permanently submerged in water, approx. 100 micrometer.
Straightening after galvanizing: All plates and shapes, which have been warped by the galvanizing
process, shall be straightened by being re‐rolled or pressed without injury to the protective coating.
Materials that have been harmfully bent or warped in the process of fabrication or galvanizing shall be
rejected.
Renewable Energy Guidelines Nov. 2013 85
Volume 12 Civil Works
7.9.2.4 Inspection and testing
The Engineer may require to inspect engineering metalwork during fabrication and to witness testing at
the fabrication shop in addition to inspections and tests undertaken on site. The CO(s) shall give the PO
Engineer 20 working days notice of any operations, which the PO Engineer has named to the CO(s) in
order that the PO Engineer may arrange to undertake such inspections.
86 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
8 Pipeworks
8.1 Materials
8.1.1 General
All materials used shall be of the best quality and of the most suitable for the application or duty
concerned. They shall be selected for long life and minimum maintenance and obtained from reputable
suppliers / manufacturers.
The materials used shall be corrosion and acid resistant or so treated to give them the necessary
protection. They shall be free of toxic substance, and shall not foster micro‐biological growth or give rise
to taste, odour, cloudiness or discolouration of the water with which they are, or could be in contact.
The workmanship and finish of all equipment shall be of the highest quality. Defects or mistakes shall
not be made good by repairs, patches or welding.
Where possible, every attempt should be made to standardise by the use of parts and components,
which are identical. This will simplify interchangeability and reduce the necessary stock of spares.
Manufactured spares should be of the same material and of the same accuracy, tolerances and finish as
the originals.
8.1.2 Working pressure
The working pressure of all equipment, pipes and materials for pressurized pipes if not otherwise
specified shall be PN 10 (1 Mpa).
The pressure rating for all pipes used for conveyance of waste, storm and drainage water shall have a
pressure rating of PN 2 (0.2 Mpa)
8.1.3 Pipes
8.1.3.1 High density polyethylene (HDPE) pipes and fittings
HDPE piped shall be manufactured according to ISO 161‐1:1996, ISO 4427 and prEn 12201.
Furthermore, the pipes shall sustain a pressure rating of PN 10, material shall be PE 100 with an SDR
(Standard Dimension Ratio) 11. Minimum ring stiffness shall be 10 kN/m².
HDPE Pipes are denominated in the Specifications and Drawings with outside diameter.
Pipes with outside diameter over 75 mm shall be delivered in 12 m straight pieces if it is foreseen to lay
them in open trench method. Pipe to be laid by trenchless methods may be supplied on drums or coils.
Transport, storage and handling shall be strictly according to the recommendations of the manufacturer.
These recommendations shall be submitted to the Engineer who shall have the right to inspect packing,
transport and storage at any time. It is emphasized that the pipes may not be stored in places where
they are exposed to open sun light.
Pipes not conforming to the above requirements will be rejected and shall not be used for the works.
Fittings such as tees, sockets, flanges etc shall conform to the same material specification as the pipes.
Renewable Energy Guidelines Nov. 2013 87
Volume 12 Civil Works
Pipes segments shall be joint by electro fusion in case of open trench laying. Pipe segments shall be
joined by butt welding in case of trench‐less methods. Valve connections in distribution pipes shall, if
not otherwise specified, flanged connections.
8.1.3.2 PVC pipes and fittings
PVC pipes and fittings shall be unplasticized PVC (PVC‐u) and manufactured in accordance with EN 1401,
EN 145, DIN 19531, DIN 8062, EN 1329‐1, ISO 3633 and ISO 8283‐1. PVC Pipes shall be Spigot‐Socket
Type, pressure rating PN 2 in pieces of 6,00 m straight length including rubber gaskets. DIN 8061 and
DIN 8063 shall apply for dimensioning.
All joints and fittings for PVC pipes shall conform to the same quality as the pipes.
8.1.3.3 Steel pipes
Steel pipes can be either welded pipes (Steel ST37.0) according to DIN 1624 or seamless pipes according
to Din 1629.
Steel pipes shall be outside corrosion protected as described in chapter 7.9
8.1.4 Joints
All joints of steel pipes shall be made as flanged joints. All metal flanges shall conform to EN 1092‐2, all
flanges drilled to DIN 2501 ‐ PN 10 unless otherwise specifically mentioned. Flanged joints for steel pipes
and for valves shall be made, unless specified otherwise, with full face rubber joint gaskets and acid
proof stainless steel bolts and nuts which shall include two washers per bolt. Joint gaskets shall be made
from 3 mm thick rubber to DIN 28617 and of such physical properties as to be capable of forming
permanent watertight joints. The use jointing paste or grease will not be permitted. No jointing material
shall be left protruding into the bore of the pipe.
All bolts shall first be tightened by hand and bolts, on opposite sides of the joint circumference, shall
then be alternatively and progressively tightened with a standard spanner so as to ensure even pressure
all round the joint. The bolts shall be of corrosion resistant materials.
Where flanged joints are to remain exposed in ducts and buildings, all damaged sheathing or coatings to
the barrels of pipes, adjacent to joints, shall be made good by cleaning the affected areas which shall
then be primed and re‐sheathed or recoated to the same thickness as the original protection. All other
surfaces of joints shall be cleaned, painted with an approved rust inhibitor and then shall receive one
coat of an approved bituminous paint.
Where pipes or joints have been supplied with their external surface bare, or primed only with a rust
inhibitor, for the purpose of later painting with non‐bituminous gloss paints, then instead of the
application of one coat of a bituminous paint they shall receive one coat of a red lead primer, before
painting.
Where flanged joints are to be buried, the exterior of all joints and their parts and the barrels of pipes,
for a distance of a 150 mm from the backs of both the joint sides, shall be cleaned of any rust, and any
damaged or loose coating, then dried. The prepared pipe surfaces, and the joint, shall then be protected
by lap wrapping, with approved water resistant tape, in accordance with the manufacturer's
instructions. The cost of this protection shall be included in the rate for making the joint.
88 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
8.1.5 Valves
All valves if not otherwise specified will be of gate valve type. Gate valves shall be of resilient sealing
type with short length, if not otherwise specified with following specification according to DIN 3352. The
design pressure is PN 10. Valves shall comply with following specifications.
Body GGG 400 ‐ DIN 1693
Stem acid protected Steel
Gate GGG 400 coated with synthetic rubber
Nut Gun Metal
The seats shall be replaceable and screwed into the body. Valves shall be flanged. All valves shall, if not
otherwise specified in the design drawings, be supplied with underground installation equipment for 1.7
to 3.0 m soil cover as per drawings, consisting of key rod of anticorrosive, PE‐protection tube and tube
cover, coupling sleeve and stem protection pins in stainless steel.
8.1.6 Hydrants
All Hydrants shall be for underground installation if not otherwise specified, size DN 100, thermo insulated type AD1 according to DIN 3221.
Renewable Energy Guidelines Nov. 2013 89
Volume 12 Civil Works
9 Fencing
9.1 General
The works comprise the supply and erection of fences and gates both around the perimeter of the site
and internal fencing. Internal fencing shall be of the Standard type and fencing around the perimeter of
the site shall be of the security type. Security fences shall be anti‐intruder type.
All items of material for fencing shall be standard products of specialized manufacturers. Posts and
struts shall be either reinforced concrete or galvanized steel sections. Timber posts shall not be used.
All wire shall be galvanized wire with plastic coating. The length of the sides of the chain link mesh shall
be 50 mm. All chain link fencing shall be barbed along the top edge.
The work pertaining to fencing shall consist of providing all necessary materials and construction of the
fencing including all requisite materials, unloading and storing on site as well as intermediate handling
as required. All earth and concrete work shall be included in the offer.
All posts and struts shall be anchored in rigid concrete C 20/25 foundations of sufficient depth. In the
vicinity of gates, structures and fence openings, adequate provisions to fix the fences shall be provided.
The distance of the bottom of the wire mesh to the leveled ground surface shall not exceed 2.5 m.
9.2 Standard fencing
Standard fencing shall consist of a 2.0 m high mesh wire fencing with steep posts of circular tubing of
high tensile steel as approved by the PO Engineer.
The posts shall be galvanized inside and outside and plastic coated and closed at the top with plastic or
cast zinc alloy caps. End, intermediate, corner and straining posts shall be 1.5 m long, gate posts 1.5 m
long. The distance between the posts shall be 2.5‐3.0 m. The posts are to be set in sufficient C 20/25
concrete foundations.
Intermediate straining posts are to be installed to 20 m intervals and at changes in line or direction.
They shall have two diagonal struts and shall be provided with 3 double ratchet winders for the strain
line wires and one joint clamp to fix the struts to the post. Strut foundations shall be cast in concrete
C 20/25 and in sufficient size.
Corner and end posts shall either be supported by struts as for intermediate straining posts or by a
horizontal bracing. Sufficient straining wires, winding ratchets, joining clamps and other fittings required
shall be provided for all end, corner and gate posts. Three rows of straining wires are to be installed for
1.0 m high fences.
9.3 Security fencing
Security fencing shall be constructed as described for Standard fencing, but with posts provided with
barbed wire holders inclined outwards.
The total fence height shall be 2.5 m. Six rows of straining wires are to be installed. Post length shall be
3.0. Three rows of galvanized and plastic coated 2 Strand, 4 point barbed wire shall be fixed to the
cranked top section of the post. Sufficient ratchet, winders and clamps are to be provided to assemble
and to secure the barbed wire.
90 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
9.4 Gates
The tops of the gate frames shall be leveled with the tops of adjacent fencing. Gates in fencing with
barbed wire on extension arms shall also carry wire mounted on extension arms as specified.
All gates shall be of welded steel construction, galvanized and painted and covered with plastic coated
chain link mesh and surmounted with galvanized plastic coated barbed wire to match the fencing.
Sliding gates shall be provided with roller support tracks.
The gates shall be complete with all fittings such as drop bolts, back catches, locking bars, lock plates
and locks including three keys per lock.
9.5 Installation
Fences shall be installed in accordance with the fence manufacturer's drawings and written Installation
instruction, except as modified herein. Each line of fencing shall be erected so that it is plumb, taut, true
to line and grade, and complete in all details. The outside face of the fabric shall be on the property line
where the fence runs along the property boundary.
Posts shall be suitably braced during concreting to ensure that they remain in the correct line and level
during placing of concrete and the concrete shall be cured for 3 days before any further work is done at
the post.
Renewable Energy Guidelines Nov. 2013 91
Volume 12 Civil Works
10 Electric motors of hydraulic steel works and cranes
10.1 General
Capacity and size of motors shall be designed by the PO(s).
All motors shall be of approved manufacture high starting torque and shall comply ‐ as far as applicable ‐
with IEC standard metric motor dimensions.
The general construction shall be stiff and rigid; no light metal alloy casings shall be accepted. All
precautions shall be taken to avoid any type of corrosion. All motors shall be fitted with approved types
of lifting hooks or eyebolts as suitable. AC motors shall have squirrel cage type rotors.
10.2 Voltage and rating
All motors shall have a voltage of 400 V. The rating of the motors shall be adequate to meet the
requirements of its associated equipment. The service factor, being the ratio of the installed motor
output to the required power at the shaft of the driven machine at its expected maximum power
demand, shall be applied as follows:
Power Demand of Driven Machine Service Factor
Up to 5 kW 1.2
More than 5 kW 1.1
A.C. motors shall be capable of operating continuously under rated output conditions at any frequency
between 95% and 105% of the rated frequency and / or with any voltage variation between 90% and
110% of the nominal voltage. A transient over voltage of 130% of the nominal voltage shall as well be
sustained.
Further, the motors shall be capable of maintaining stable operation when running at 70% nominal
voltage for a period of 10 seconds. The pullout torque for continuously loaded motors shall be at least
160% of the rated torque and for intermittently loaded motors
10.3 Starting
The maximum starting currents (without any tolerance) shall not exceed the following values:
2.5 times of rated current for low voltage motors rated 100 kW or above
2 times of rated current for D.C. motors (by means of starting resistors)
Motors shall be able to withstand five cold starts per hour, equally spaced. In addition, each medium
voltage motor shall be capable of enduring two successive starts with the motor initially at operating
temperature. Each low voltage motor shall be capable of withstanding three successive starts under the
same conditions or once every fifteen minutes without detrimental heating.
Motors for frequent automatic starting shall have an adequate rating. In the motor list the Contractor
shall state the frequency of starts permitted in compliance with the motor design.
92 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
10.4 Insulation class
The insulation of all motors shall be of NEMA class F but maintain in operation the temperature limits of
NEMA class B materials. It shall be suitable for operation in damp locations and for considerable
fluctuations in temperature.
10.5 Ventilation and type of enclosure
All motors shall be of the totally enclosed fan‐cooled type, protection class IP 54 according to IEC
recommendation 144. Cable termination points shall be of class IP 55.
All motors shall have a closed internal cooling air circuit re‐cooled by an external cooling air circuit
drawn from the opposite side of the driving end.
Vertical motors shall be provided with a top cover to prevent the ingress of dirt etc.
10.6 Bearings
As far as possible, the motors shall have sealed ball or roller bearings lubricated for live. Motors with
ratings of about 1 kW and above shall be equipped with lubricators permitting greasing while the motor
is running and preventing over‐lubrication (automated lubrication). Additionally the bearings shall be
fitted with grease nipples permitting the use of a universal grease gun. Vertical motors shall have
approved thrust bearings.
10.7 Control
The motors for cranes shall be controlled locally at location of the crane. The motors for gates/valves
shall be controlled from the control centre. Connection and cabling to the control centre shall be
responsibility of the E&M Contractor.
10.8 Tests
Each motor shall be factory tested and shall undergo a test at site. The following tests shall be
performed under full responsibility of the CO(s).
Workshop Tests:
Measurement of winding resistances
No‐load and short‐circuit measurements
Measurement of starting current and torque
Efficiency measurement (type test)
Heat test run
Dielectric test
Measurement of insulating resistance.
Renewable Energy Guidelines Nov. 2013 93
Volume 12 Civil Works
11 Environment and community
The CO(s) shall comply with the following social and environmental Sections of the Specification.
11.1 Public relations
11.1.1 Land
The CO(s) shall provide the land to the project and responsible to resolve associated disputes, if there
will be any.
11.2 Employment
The CO(s) shall have an equal opportunity policy of employment, which shall take into account and give
priority to:
locally available workers a)
women and marginalized people b)
low caste people c)
maximizing the employment opportunity across the local community. d)
11.3 Land interests
11.3.1 Interference with land interest
The CO(s) shall confine his constructional operations within the Project Site, or such other areas of land
as may be negotiated and agreed with the PO, and shall instruct the workers not to trespass.
11.4 Protection against damage
The CO(s) shall take all necessary precautions to avoid causing any unwarranted damage to roads, lands,
trees and other features. In case of damage, it shall immediately address complains by owners or
concerned person.
11.5 Watercourses
The CO(s) shall be responsible to maintain the water quality in watercourses. The CO(s) shall take all
practicable actions, which shall be according to the prior approval of the PO Engineer, to prevent the
deposition of silt to a level above the prevailing conditions at that time.
The CO(s) shall prevent the pollution of any existing watercourse, canal, lake, reservoir, borehole,
aquifer or catchment area, as a result of his operations.
11.6 Waste disposal
Waste that can be burned shall be burned on the Project Site in a specific location, incinerator, as
approved by the PO Engineer.
94 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
The CO(s) shall be permitted to bury organic and non‐toxic waste on the Project Site. The site for
burying waste shall be to the approval of the Engineer. After waste is buried, a layer of soil shall be
placed over all rubbish in order to reduce odors and deter vermin.
Toxic waste shall be taken off the Project Site and removed to a designated tipping area approved by the
PO Engineer. Waste grease and oil shall be disposed of as specified or directed by the PO Engineer.
The CO(s) shall encourage recycling of waste, where this is practicable.
11.7 Final clean‐up and landscaping
11.7.1 Clean‐up
All land retained for the Permanent Works shall be returned in a safe and tidy condition. All waste
materials shall be properly disposed of in such a way that there is no risk of causing harm to the
environment or injury to people or animals after the completion of the project.
11.7.2 Final landscaping
Final landscaping shall be to the satisfaction of the PO Engineer.
Spoil tips shall be left in a stable manner and not be prone to erosion. Spoil tip slopes shall be left with a
safe slope angle adequately drained.
Where the land to be returned may be used for agriculture the existing topsoil (if any) shall be re‐spread
after completion. In re‐spreading, care should be taken to prevent excessive compaction.
On completion of the works, the project should ensure that all temporary sites are restored as near as
possible to the original condition, as specified in the TOP.
Renewable Energy Guidelines Nov. 2013 95
Volume 12 Civil Works
12 Tests on completion, commissioning and acceptance
12.1 Tests
The CO(s) shall perform all necessary tests to demonstrate compliance of the Works with the
specifications, performance criteria and guarantees. During the tests the CO(s) shall demonstrate that:
The Works complies fully with the Specification
The tests shall include, but not be limited to:
Inspection and testing at the manufacturers' premises (Factory tests).
Inspection and testing during construction
Tests on Completion (Commissioning and Performance Tests)
A minimum of 21 days notice in writing shall be given to the PO Engineer and the PPAF prior to carrying
out any major testing.
The CO(s) shall prepare a comprehensive commissioning and testing programme and details of the
inspection and test procedures he proposes to employ for the start‐up of the Works and this shall be
submitted to the PO Engineer for approval at least 60 days prior to the commencement of the Tests on
Completion.
12.2 Inspection and testing during construction
Tests during construction shall include but not be limited to the following:
All specified tests and sampling for materials to be incorporated into the permanent works
All water retaining structures including concrete tanks, manholes, building roofs etc. shall be tested to prove the water tightness in accordance with the Specification.
All gates and stop‐logs function as per requirement.
All pipelines (gravity or pressure pipes) shall be pressure tested
Compaction tests shall be performed for in backfill areas, under the foundation of concrete structures, for pipe beddings, for sub‐layers and layers of road works
All materials supplied for incorporation in the works shall be new and subject to Quality Assurance Inspection, certification and where appropriate destructive testing in order to demonstrate compliance with the requirements of the Specification and the purpose for which they are employed. Where quality assured materials are not readily available, and where materials are required to comply with Standards, the CO(s) shall submit to the PO Engineer test certificates, issued by a recognized institution, furnished by the supplier or manufacturer of the materials indicating their compliance with the relevant Specification.
Procedures and work processes for the recording of test results shall be set out in the PO's Quality
Assurance Plan but in any case the test results shall be reported in writing to the PO by the CO(s) with
the comments and endorsement of the PO Engineer.
Where specialized test equipment is supplied, the CO(s) shall provide the associated test sheets, which
shall be submitted to the PO Engineer for review prior to the tests being carried out.
96 Renewable Energy Guidelines Nov. 2013
Volume 12 Civil Works
12.3 Tests on completion and handing‐over procedure
Tests on Completion are in detail compiled in the following Volumes of the PPAF HRE Guidelines and
Manuals:
Volume 8: Transmission & Distribution
Volume 9: Electro‐Mechanical Equipment
Volume 10: Commissioning Guidelines.