SALAM SEJ AHTERA

SALAM SALAM SEJ AHTERASEJ AHTERA

WATER SUPPLY PIPELINES WATER SUPPLY PIPELINES & &

PIPELINE SYSTEMSPIPELINE SYSTEMS

PEMASANGAN PAIP BEKALAN AIR PEMASANGAN PAIP BEKALAN AIR & &

SISTEM PEMASANGAN PAIP SISTEM PEMASANGAN PAIP BEKALAN AIRBEKALAN AIR

PENSYARAHPENSYARAH

• IR. HJ. ZAINAL ABIDIN BIN IBRAHIM

JADUALJADUALHARI PERTAMA. 08.30PG – 10.30PG - PENGENALAN SISTEM-SISTEM

PEMASANGAN PAIP BEKALAN AIR.Introduction to water pipe systems

10.30PG – 13.00TGH - JENIS-JENIS PAIP DAN JENIS-JENIS SPESIAL, FITTING DAN INJAB-INJAB.Types of pipes, types of special & fittings and type of valves

14.15PTG – 15.15PTG - PAIP STANDARD DAN SPESIFIKASIPipes Standard & Specifications

15.30PTG – 16.15PTG - CARA-CARA PEMASANGAN PAIP, SAMBUNGAN, SPESIAL, FITTINGS, INJAB-INJAB DAN LAIN-LAIN.Methods of Laying of Pipes, joints, joints with specials and fittings and installation of valves etc.

JADUALJADUALHARI KEDUA. 08.30PG – 10.30PG - PEMASANGAN PAIP

Laying of Pipe works

10.30PG – 13.00TGH - KAEDAH PEMASANGAN PAIPMethod of Laying of Pipes

14.15PTG – 15.15PTG - UJIAN-UJIAN PAIPField Testing of Pipes

15.30PTG – 16.15PTG - KESILAPAN-KESILAPAN KE BIASAAN DITAPAK & KEGAGALANCommon Construction Errors Defects & Failures

Day 1

CONTENT

1.1      Introduction

1.2      Objectives

1.3      Type of Distribution

1.4      Distribution Layout

1.5      Pipes

1.6 Pipes Joints

1.7      Fittings & Specials

1.8      Valves

1.9      Pipe Diameter Selection

1.10    Design of pipe profiles

 

Day 2

2.0    Laying of Pipe works

2.1  Method of Contract

2..2    Method of Laying of Pipes

2.2.1  Trench Excavation

2.2.2 Bulk Excavation

2.2.3 Excavation in Hard Material or Rock

2.2.4 Field Testing of Pipes

2.2.5 Leakage Test

2.2.6 Pressure Test

2.2.7 Air testing of Welded Joints

2.2.8 Disinfecting & Flushing Pipelines

2.3 Common Construction Errors Defects & Failures

 

 

1.0 PENGENALAN  The water distribution system consists of transmission, distribution and reticulation pipelines, balancing and

service reservoirs and where required, booster pumping stations.

Sistem pengagihan air merangkumi pemindahan, pengagihan dan retikulasi rangkaian paip., pengimbangan dan servis-servis tangki-tangki air dimana ia memerlukan stesen pam injakan.(booster station)

2.0 OBJECTIVES

  The objective of a water distribution system is to supply potable water, at sufficient pressure and quantity, to

the consumers.

Objektif sistem agihan air ialah membekal air yang mana ianya mengikut keperluan , juga

pada tekanan serta kuantiti yang mencukupi pada para pengguna.

 

3.0 TYPES OF DISTRIBUTION SYSTEMSA water distribution system may be classified into three types, namely;

a)     a gravity system,

b)    a direct pumped system, and

c)     a gravity and pumped combination system

Sistem pengagihan air boleh diklasifikasikan kepada tiga jenis;

a) yang disebut sebagai sistem graviti,

b) sistem pam secara langsung dan

c) sistem kombinasi pam dan graviti.

 

Item

No

Systems Advantages Disadvantages

1 Gravity 1a.      Most reliable reliable

b.     Low operationab. Low Operational

b.     Low operationaa.   Most Costs

Cost

Cost

None

2 Pumped & Gravity Combination

a. Problem associated

with operation and

maintenance of

pumping systems

3 Direct Pumped

  a.      Pressure and flow can be

easily regulated

Remedial action can be

speedily taken

a. Problem associated

with operation and

maintenance of

pumping systems

TABLE 1.1 – ADVANTAGES AND DISADVANTAGES OF THE TYPES OF DISTRIBUTION SYSTEMS.

Delivery Main by Gravity

Paip Agihan Secara Graviti

 1.1 DISTRIBUTION LAYOUT 

General considerations to be taken during the planning of distribution layout are: -

 a)     The service reservoir shall be as close and central as possible to the water demand area. The

pipeline shall be as short as possible, thus providing the least capital and operating costs.

 b)     Where the service reservoir cannot be sited close to the demand area, a twin pipeline layout shall be given consideration.

 c)     The reticulation pipes shall be laid so as to form a network system. Dead ends shall be discouraged.

 d)     Where extreme topographical conditions prevail in demand areas, such as greater then 40 meters difference in elevation, pressure

zoning of service areas according to ground elevations way be necessary. This can be achieved by using pressure reducing valves or

break pressure tanks.

e)     Pipelines shall preferably be laid adjacent to roads so as provide easy access for maintenance.

 

 

     Susunatur Pengagihan

Secara amnya, pertimbangan yang harus dititikberatkan dalam perancangan susunatur untuk sistem agihan:

  a)  a) Kawasan takungan air atau pusat simpanan air sebolehnya pada jarak terdekat dan ditengah-tengah kawasan yang perlu diagihkan tersebut. Rangkain paip seboleh-bolehnya dipendekkan dimana ianya menyumbangkan dari segi kos dan tenaga kerja untuk pengurusan.

 

b)  b) Dimana kawasan simpanan air jauh dari kawasan agihan, rangkaian paip berkembar harus dipertimbangkan.

 

c)  c) c) Paip retikulasi harus digunakan untuk mewujudkan sistem rangkaian paip yang lengkap. Elakkan daripada wujudnya “dead ends”. (hujung mati)

 

d)      

d) d) apabila ciri-ciri topografi yang ekstrim wujud di kawasan agihan , seperti contoh perbezaan aras melebihi 40 meter, zon tekanan di kawasan agihan mengikut aras tanah adalah diperlukan. Ini boleh dicapai dengan menggunakan injap pengurangan tekanan ataupun tangki pemberhentian tekanan.

 

e) Rangkaian paip seboleh-bolehnya diatur dipertemuan bersamaan jalan raya untuk kemudahan penyelenggaraan.

 

PIPES 

1.0       Pipes Materials

PIPES

 Pipes Materials

1.0  Cast Iron (C.I.)

C.I. pipes shall conform to MS 708 : 1981. The pipe is strong but brittle. It usually offers a long service life and is reasonably maintenance free.

Because C.I. pipes have relatively good resistance to corrosion, the JKR Standard specifications only require an internal and external coating of either hot applied coal tar or hot dipped bitumen . C.I. pipes are manufactured in standard lengths of 3.0, 4.0 and 5.5 meters. C.I. pipes to this Malaysian Standard have outer diameters, which are the same as ductile iron pipes and as such allow the use of ductile iron fittings. Current available sizes are of 100mm to 250mm nominal diameters, though the JKR Standard Specification allows nominal diameters up to 600mm, as given in Table 1.3.

 

The cast iron pipes usually used are of socket or flanged ends. No screwed-on type of flanged pipes shall be used.

 

1.1.1.1                        Ductile Iron (D.I.) Pipes

 

DUCTILE Iron Pipes shall conform to BS4772:1988. D.I. pipes resemble cast iron pipes in appearance and have many of the same characteristics. However, D.I. pipes are stronger and tougher than the cast iron pipes.

 

All DI pipes shall have an external zinc coating before coal tar epoxy or bitumen is applied on its external surface. The internal surface shall be cement mortar lined.

 

Standard length of D.I. pipes vary from 4.0 meters to 6.0 meters. Nominal diameters range from 80mm to 1600mm.

1.1.1.1                        Asbestos Cement (A.C.) 

AC pipes shall conform to MS712:1981. The minimum class of AC pipes used shall be of class 20. 

Almost all AC pipes are used without any further coatings

 AC pipes are manufactured in standard lengths of 4.0 meters. Nominal diameters range from 80mm to 600mm. The thickness and diameter of AC pipes is given in Table 1.5

 AC pipes shall not be used in marine or corrosive soils.

1.1.1.1                        Steel Pipes

 

1. Steel pipes are widely used in the water industry.

2. The pipes shall conform to the requirements of BS 534:1981, with the exception of

their external diameter and thickness, as indicated in Table 1.6 below.

3. The external coating shall consist of a layer of bitumen containing a mineral filter. It is reinforced with an inner and outer wrapping of glass fiber resin bounded tissue and reinforced in the longitudinal direction with parallel glass threads.

4. The internal lining for the steel pipes shall be of concrete. Steel pipes, which are to be used above ground shall not be coated, but painted with zinc chromate and aluminum paint.

 5. Steel pipes may be as large as 2.0 meters diameter but steel pipes used in JKR usually range from 100mm to 900mm diameter. For steel pipe diameters up to 600mm, the external diameter is the same as that of asbestos cement pipes.

 6. Pipes having 450mm diameter and above have a standard length of 9.0meters while those of 450mm diameters and below are 6.0meters long. However, steel pipe manufacturers can easily produced pipes to various specific lengths.

1.1.1.1                        High Density Polyethylene (HDPE)

 

HDPE pipes shall conform to MS1058:1986. At present, HDPE pipes are gaining greater acceptance in the water supply industry, largely due to its high flexibility, very good corrosion resistance and other favorable properties.

 

No coating has been specified for HDPE pipes.

 

HDPE pipes have outside diameters ranging from 75mm to 800mm. For pipes having outside diameters of 90mm and below, the standard length is 6meters, while those of outside diameters of 110mm and above have a standard length of 12 meters. Pipes of outside diameter less than 110mm can be supplied in coils.

 

Dimensions for wall thickness and pipe diameter are given in Table 1.7.

1.1.1.1                        Unplasticised Polyvinyl Chloride (uPVC)

 

UPVC pipes are semi-rigid pipes. They are required to comply with MS628:1982.

 

No coating has been specified for uPVC pipes.

 

The standard length for uPVC pipes is 6 meters. Nominal diameter can range from 80mm to 575mm, but pipes larger than 300mm have yet to be used extensively in the water supply industry.

 

Table 1.8 gives the thickness and diameter of uPVC pipes.

 

Glass-fiber Reinforced Plastic (GRP)

 

GRP pipes are relatively new and have not been used widely in Malaysia. GRP pipes shall conform in BS5480 Part 1: 1977. No coating has been specified for GRP pipes.

 

The GRP pipe manufacturer shall design the pipe wall thickness based on various parameters as spelt out in the British Standard. Standard lengths of pipes are 3.0, 5.0, and 6.0 meters.

 

Since GRP pipes are easily deformed and there is little experience on the use of these pipes, nominal diameters shall be limited to a maximum of 1600mm though BS5480 has allowed for much larger diameters.

 

1.5.2      Pipe Classification

 

The values of maximum permissible working pressure for the various classes of pipes, made to the above mentioned standards are as given in Table 1.9

1.1.1       Selection of Type of Pipes

 

The pipes shall be selected such that the maximum operating pressure or the internal design pressure, including surge pressure, shall not exceed the maximum permissible working pressure rating of the pipe. Where there is a substantial amount of surge pressure, protective surge devices shall be installed to ensure that the pressure do not exceed the maximum permissible working pressure rating of the pipes.

1.1.1       Selection of Type of Pipe.

 

The major factors to be considered when selecting the type of pipe are:-

 

a)     Working and test pressures, including surge pressure.

b)     Strength of pipe to withstand designed internal and external loads.

c)     Durability of the pipes

d)     Suitability and workability for laying and operating requirements

e)     Capital, operation and maintenance costs.

f)       Extend of possible leakage.

 

Having considered the above factors, recommendations on the use of the various pipes are as given in Table 1.10. These recommendations serve only as a guide and the above-mentioned factors, as well as other pertinent factors, may well determine the type of pipe to be used.  

 

1.1 JOINTS

 

A particular type of the pipe can be joined with one or more types of joint to suit the circumstances in which the pipeline is laid and has to operate. Table 14.11 gives the type of joints, which are commonly available for pipes and specials. Typical sections for the various joints are given in Figure 1.2., many others less commonly used joints are available but not described below.

 

1.1.1       Flanged Joint

 

Flanged joints are used for exposed pipe works, in booster pumping stations, spanning overhead crossing and where rigid pipe work is required.

Flanges can be cast-on as an integral part of the pipe or specials, or welded-on to the pipe or specials.

 

The thickness of the flanges, their diameters, the number and size of the bolts are determined by the duty the pipeline has to perform. Further details on these can be found in BS4504:1969.

 

For maximum permissible working pressures of 16 bar and below, steel flanges shall conform to Table 16/3 – BS4504:1969, whereas cast iron flanges shall conform to Table 16/11 of the same BS.

 

All other flange types shall be dimensionally similar to that of Table 16/11.

1.1.1       Welded Joint

 

Welded joints are commonly use for steel pipes. They are suitable for all pressures and can be used on pipelines above and below ground.

 

The socket and spigot welded joint is usually used when jointing long lengths of pipelines. This joint can be deviated up to 2 degrees, so that the pipeline can be laid on a gentle curve. Collar joints are also sometimes used for short lengths of exposed pipelines. Pipes having outside diameters greater than 700mm shall be welded internally and externally to enable testing of the joint.

 

Butt-welded joints are least preferred and are used on small pipes up to 150mm.

1.1.1       Gibault Joint

 

A gibault joint is a flexible, cast iron detachable joint. It is used extensively when connecting asbestos cement pipe with plain-ended pipes and specials of the same external diameters such as steel pipes.

 

Available gibault joints are made to maximum permissible working pressures of 10.0 and 12.5 bars.

1.1.1       Flexible Mechanical Joint

 

Flexible Mechanical Coupling will join plain-ended pipes and fittings of the same external diameter and can be made to specified external diameters. The coupling is suitable for pipes liable to be subjected to ground movement and settlement, thermal expansion and contraction and along vertical pipelines. The Viking Johnson Coupling is one such example.

1.1.1       Butt Fusion

 

The butt fusion technique involves heat welding the pipe, either as two butt ends or as a socket fitting, using a heating plate. These joint enables long lengths of flexible HDPE pipelines to be formed and are suitable where there is ground movement or when the pipelines must be laid on a curve.

 

1.1.1       Sleeve Coupling

 

Sleeve couplings joint plain-ended pipes of the same diameter. The material for the sleeve is usually of the same material as the main pipe.

 

Sleeve couplings of the solvent type are used for uPVC pipes not exceeding 155mm nominal diameter. The more common sleeve couplings use the rubber ring, as in uPVC coupler, AC sleeve and the GRP pipe joints.

 

The sleeve couplings of the rubber ring type are flexible which allow varying degrees of deflections, depending on the type of the sleeve coupling used; AC joints for example, allow 4 to 8 degrees deflection for pipes up to 250mm diameters, while pipe diameters larger than 250mm allow 1.5 to 3.5 degrees.

1.1.1       Push-on Spigot & Socket

 

These joints are formed by a rubber ring, forced into a sealing position by the entry of the spigot end into the socket end of the pipe. These joints are also flexible and permit some degree of deflection. Many ductile iron pipelines use this push-on type (sometimes called T-type) of joints allow deflection of 4 to 10 degrees. Other types of spigot and socket joints are also used in jointing uPVC as well as G.R.P. pipes.

1.1.1       Single Gland – Mechanical Joint

 

The joint is sometimes referred to as the K-type mechanical joint and is also commonly used with spigot and socked ductile iron pipes. This type of joint is also flexible and permits varying degrees of deflection (3 degreestp10 degrees), depending on the diameter of the pipe.

Stepped Coupling

 

 

Stepped couplings are used to form joints of plain-ended pipes of small differences in external diameters. A.V.A. dresser joint which connects a uPVC and an A.C. pipe, is a typical example.

1.1 FITTINGS AND SPECIALS

 

A wide range of pipe fittings and specials is available to facilitate a change in pipe diameters and joints, change in pipeline direction and the installation of miscellaneous items in the water distribution systems. Only the commonly used types of fittings and specials are discussed below. Figure 1.3 shows various typical flanged fittings and specials.

a)                 Tapers.

 

Tapers, whether concentric or flat/eccentric, are used to connect pipes and fittings of different diameters. Concentric tapers are widely used in most pipelines whereas flat tapers are used are suction pipes. Tapers can be made from C..I.., D.I., uPVC, HDPE. GRP of steel and may be plain-ended, double flanged, or one end flanged and the other plain-ended.

 

Flange Adaptors

 

When transferring form a flexible to a rigid jointing system, for example incorporating a double-flanged sluice valve in a plain-ended pipe, flanged adaptors are used. These specials are available in C.I.,D.I. of steel.

1.1.1       Flanged Joint 

Flanged joints are used for exposed pipe works, in booster pumping stations, spanning overhead crossing and where rigid

pipe work is required.

Flanges can be cast-on as an integral part of the pipe or specials, or welded-on to the pipe or specials.

 1.1.1       Welded Joint Welded joints are commonly use for steel pipes. They are suitable for all pressures and can be used on pipelines above and below ground. The socket and spigot welded joint is usually used when jointing long lengths of pipelines. This joint can be deviated up to 2 degrees, so that the pipeline can be laid on a gentle curve. Collar joints are also sometimes used for short lengths of exposed pipelines. Pipes having outside diameters greater than 700mm shall be welded internally and externally to enable testing of the joint. Butt-welded joints are least preferred and are used on small pipes up to 150mm.

1.1.1       Gibault Joint A gibault joint is a flexible, cast iron detachable joint. It is used extensively when connecting asbestos cement pipe with plain-ended pipes and specials of the same external diameters such as steel pipes. Available gibault joints are made to maximum permissible working pressures of 10.0 and 12.5 bars.

1.1.1       Flexible Mechanical Joint Flexible Mechanical Coupling will join plain-ended pipes and fittings of the same external diameter and can be made to specified external diameters. The coupling is suitable for pipes liable to be subjected to ground movement and settlement, thermal expansion and contraction and along vertical pipelines. The Viking Johnson Coupling is one such example

1.1.1       Butt Fusion  The butt fusion technique involves heat welding the pipe, either as two butt ends or as a socket fitting, using a heating plate. These joint enables long lengths of flexible HDPE pipelines to be formed and are suitable where there is ground movement or when the pipelines must be laid on a curve. 

1.1.1       Sleeve Coupling Sleeve couplings joint plain-ended pipes of the same diameter. The material for the sleeve is usually of the same material as the main pipe. Sleeve couplings of the solvent type are used for uPVC pipes not exceeding 155mm nominal diameter. The more common sleeve couplings use the rubber ring, as in uPVC coupler, AC sleeve and the GRP pipe joints. The sleeve couplings of the rubber ring type are flexible which allow varying degrees of deflections, depending on the type of the sleeve coupling used; AC joints for example, allow 4 to 8 degrees deflection for pipes up to 250mm diameters, while pipe diameters larger than 250mm allow 1.5 to 3.5 degrees.  

1.1.1       Push-on Spigot & Socket These joints are formed by a rubber ring, forced into a sealing position by the entry of the spigot end into the socket end of the pipe. These joints are also flexible and permit some degree of deflection. Many ductile iron pipelines use this push-on type (sometimes called T-type) of joints allow deflection of 4 to 10 degrees. Other types of spigot and socket joints are also used in jointing uPVC as well as G.R.P. pipes.