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C:\09\048_GreenstarLtd.\25_DecomPlanWaterford\04802501 October 2009 (JOC/MG/MS)
FIRE WATER RISK ASSESSMENT
GALWAY METAL COMPANY
ORANMORE
COUNTY GALWAY
WFP-11-G-0005-01
Prepared For: -
Galway Metal Company Ltd
Oranmore,
Co. Galway
Prepared By: -
O’ Callaghan Moran & Associates,
Granary House,
Rutland Street,
Cork
September 2014
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Project Fire Water Risk Assessment
Client Galway Metal Company Ltd
WFP-11-G-0005-01
Report No Date Status Prepared By Reviewed By
1961601 23/09/2014 Final Michael
Watson MA
Jim O’Callaghan MSc, CEnv,
MCIWM, IEMA
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TABLE OF CONTENTS
PAGE
1.� INTRODUCTION ............................................................................................................ 1�
2.� FACILITY OVERVIEW ................................................................................................. 2�
2.1� FACILITY LOCATION .................................................................................................................................. 2�
2.2� SITE LAYOUT ............................................................................................................................................. 2�
2.3� SITE ACTIVITIES ........................................................................................................................................ 2�
2.4� SURFACE WATER DRAINAGE ..................................................................................................................... 4�
2.5� WASTEWATER ........................................................................................................................................... 4�
2.6� GROUND CONDITIONS: .............................................................................................................................. 4�
2.6.1� Soils and Subsoil ............................................................................................................................. 4�
2.6.2� Bedrock ........................................................................................................................................... 5�
2.7� HYDROGEOLOGY ....................................................................................................................................... 5�
2.7.1� Aquifer Classification ...................................................................................................................... 5�
2.7.2� Aquifer Vulnerability ....................................................................................................................... 5�
2.7.3� Groundwater Flow Direction and Proximity to Wells .................................................................... 5�
2.7.4� Groundwater Dependant Terrestrial Ecosystems. .......................................................................... 5�
3.� OPERATIONAL AREA .................................................................................................. 7�
3.1� EXTERNAL YARD & PAVED AREAS ........................................................................................................... 7�
3.2� MAIN BUILDING ........................................................................................................................................ 7�
3.3� BUNDED AREA .......................................................................................................................................... 7�
3.4� CAR PARK ................................................................................................................................................. 7�
4.� FIRE CHARACTERISTICS OF PRODUCTS ON-SITE ........................................... 8�
4.1� MATERIALS CLASSIFICATION .................................................................................................................... 8�
5.� FIRE SAFETY MANAGEMENT SYSTEM ............................................................... 10�
5.1� FIRE FIGHTING MANAGEMENT SYSTEM .................................................................................................. 10�
5.2� FIRE PREVENTION MEASURES ................................................................................................................. 10�
5.2.1� Storage of Combustible and Flammable Materials ....................................................................... 10�
5.2.2� Control of Sources of Ignition ....................................................................................................... 10�
5.2.3� Safety Audits .................................................................................................................................. 10�
5.3� FIRE DETECTION ...................................................................................................................................... 10�
5.4� FIRE SUPPRESSION ................................................................................................................................... 11�
6.� FIRE WATER RISK ASSESSMENT .......................................................................... 12�
6.1� POTENTIAL FIRE LOAD CRITERIA ............................................................................................................ 12�
6.2� FIRE RISK CRITERIA ................................................................................................................................ 12�
6.3� ENVIRONMENTAL LOAD .......................................................................................................................... 13�
6.4� ENVIRONMENTAL RISK CRITERIA ............................................................................................................ 14�
6.5� RISK ASSESSMENT ................................................................................................................................... 14�
6.6� SOURCE-PATHWAY-RECEPTOR RISK ASSESSMENT ................................................................................. 17�
7.� CONCLUSIONS............................................................................................................. 18�
7.1� CONCLUSIONS ......................................................................................................................................... 18�
7.2� RECOMMENDATIONS ............................................................................................................................... 18�
APPENDIX 1 - Site Layout
APPENDIX 2 - Drainage Calculations
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1. INTRODUCTION
The Galway Metal Company Ltd (Galway Metal) facility at Oranmore operates under a Waste
Permit (WFP-11-G-0005-01) issued by Galway County Council (the Council) on the 11th July
2011.
Condition 4.10.1, of the Permit requires the preparation a fire water risk assessment, and
Condition 4.10.2 stipulates that, if the assessment identifies there is a significant risk of the
release of contaminated firewater, a suitable risk management programme must be prepared
and implemented. Condition 4.10.3 requires the assessment to be completed in accordance
with the Environmental Protection Agency’s (Agency) Draft Guidance Note to Industry on
the Requirements for Fire-Water Retention Facilities.
Galway Metal appointed O’Callaghan Moran & Associates (OCM) to complete the
assessment. The assessment, which was based on the Agency’s draft Guidance Note. The
assessment included: -
• The identification of existing and potential hazards (evaluation of the materials and
waste products typically stored on-site).
• A review of existing control measures, and
• An assessment of the hazards associated with: -
i. The probability of an accident occurring,
ii. Its impact both on-site and off-site (soil, water and air), and
iii. The impact of an incident on sensitive receptors (residents, schools, businesses,
hospitals etc).
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2. FACILITY OVERVIEW
2.1 Facility Location
The site is located in Oranmore, approximately 8km to the east of Galway City. The landuse
in the surrounding area is a mix of commercial and industrial activities.
2.2 Site Layout
The site layout, including the drainage system, is shown on Drawing No 1 Rev PL in
Appendix 1. It encompasses approximately 1.45hectares (ha). The ground slopes gently from
north to south from 15.3 metres Ordnance Datum (mOD) at the northern boundary to 13.3
mOD at the southern boundary.
The facility includes a car park, administration offices, a weighbridge at the site entrance,
external paved storage and processing areas and one main building divided into discrete units.
The central section of the building contains designated processing areas for recycling of non-
ferrous, aluminium and new and reusable steel and end of life vehicles. The eastern section is
occupied by a vehicle and plant maintenance garage, with offices in the western section.
The remainder of the facility is occupied by external materials storage, handling and
processing areas. The main processing area (7,993m2) includes separate storage bays for cast
aluminium, aluminium turnings, stainless steel turnings, cable and stainless steel storage. To
the east of the main building is an oil storage bund, which is used to store waste oil removed
from the end of life vehicles (ELV) and fuel for the onsite plant and collection fleet.
Details of the area of the individual buildings and storage areas and the existing drainage
measures are presented in Table 2.1.
2.3 Site Activities
The facility accepts and processes scrap metal and ELV. The processing involves manual
separation of the metals into different types: vehicle de-pollution; shredding, segregating and
sizing of metals. The majority of the processing and storage activities are carried out in the
open yard in the centre of the site and inside the main building.
Diesel is stored in the bund located in the north east corner of the site. Lubricating and hydraulic
drums are stored on spill trays in the garage and workshop, which are inside the main building.
Waste oils generated during plant maintenance and the de-pollution processes are stored in
containers integral to the ELV de-pollution unit and in the main bund at the north east corner of
the site. Oil spill containment and clean-up equipment are maintained at strategic locations
around the site.
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Metal and metal compounds are delivered by vehicles operated by Galway Metal and third
party waste contractors. Each load is inspected by an Incoming Materials Inspector (IMI),
who rejects loads that are not suitable and quarantines any materials that not listed in the
Permit.
Depending on the types of materials, the waste is directed to either the main processing
building, or the external yard areas for storage or processing. Following processing the
materials are sent to overseas foundries (Spain, Portugal, France and the UK) where they are
smelted for re-use.
The main activity is the manual separation of the various types of metals, which are then
stored pending consignment. Some of the materials are sheared using a Leimbach Shears to
reduce the size to a level suitable for shipment. The shears is powered by a number of electric
motors, with the electricity supplied by an on-site diesel powered generator.
Copper is baled in a small electrically powered baler in the western section of the main
building. Other metals are baled using an electrically powered Taurus Baler, the motors of
which are located in a lean-to building at the southern boundary of the site. Vehicle wheels
are crushed in an electrically powered crusher located inside the main processing building
adjacent to the copper store.
All ELV are de-polluted inside the main building using a dedicated De-Pollution Unit. The
de-pollution process is mainly mechanical, using gravity to drain fluids from the vehicles.
The fluids are stored in a series of bunded tanks adjacent the de-pollution unit.
The separation, stockpiling and loading of the materials is carried out using five (5 No.) diesel
powered mechanical grabs and five (5 No.) diesel powered forklifts.
Table 2.1 – Site Infrastructure
Ref Infrastructure Description
1 Office &
Administration -
Building Unit
Area 200m2. No internal drains. Contains offices and
administration areas including canteen. Limited volumes of
flammable or combustible materials stored.
2 Processing & Storage –
Building Units (x4)
Area 1,000m2. No internal drains. Houses interconnected
units, used for – ELV De-pollution, valuable metal
processing & storage, copper wire stripping. Limited
volume of flammable or combustible materials stored.
3 Maintenance Garage &
workshop Unit –
Building Unit
Area. 200m2 – No internal Drains. 10m x 2m x 1.5m blind
floor sump – vehicle and plant maintenance. Limited
volume of flammable or combustible materials stored.
4 Central Yard &
External Processing
Area
Area. 10,020m2 – Weighbridge area, vehicle maneuvering
areas, central stockpile yard, external processing areas.
Runoff is directed via a series of silt traps and interceptors
to a drain at the southern boundary. A shut off valve is
installed prior to the interceptors at the southern boundary.
5 Oil Storage Bunds Located at north east corner – Tank 1 (10m3), Tank 2 (3.5m3
diesel), Tank 3 (3.5m3 diesel)
6 Car Park & Roof Main
Building
Area 2,720m2. The car park is located to the north of the
building. Runoff from the car park and roof of the building
bypasses the drainage system serving the yard and
processing areas and discharges directly to the drain at the
southern boundary.
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2.4 Surface Water Drainage
The site occupies an area of approximately 1.45 hectares. It is completely covered by a
combination of buildings and paving. Prior to October 2013 all rainwater run-off from the
facility discharged to a drain along the southern boundary of the Business Park. In February
2013, Galway County Council granted GMC a Trade Effluent Discharge Licence (S/80/12) to
discharge run-off from the paved operational yards to the foul sewer.
Surface water from the building roofs and the car park is collected and discharged to the drain
that runs along the southern boundary of the Business Park. Runoff from the external
operational and storage area is collected and directed to silt traps and then to a Class 1 Full
Retention Klargester Oil Interceptor before entering an above ground attenuation tank.
The tank has a capacity of 400m3 and provides temporary storage for the surface water before
it is discharged to the foul sewer at a maximum rate of 4 litres/second (l/s). The foul sewer
connection is shown on Drawing No 1.
The size of the attenuation tank was based on the requirements of Galway County Council
and the design parameters are a 1:100 year return storm event (102.8mm over 24 hour
period), an impermeable area of 1.07ha and a maximum discharge rate to the foul sewer of
4l/s. The maximum storage capacity required is 754 m³.
This is accommodated by a combination of the attenuation tank (400m3) and retention
(390m3) within the southern area of the site, which is provided by a 300mm high kerb along
the southern site boundary. The combined storage capacity is 790m3. Full details on the
design of the attenuation capacity is provided in Appendix 2.
2.5 Wastewater
Sanitary wastewater from the toilets discharges to the foul sewer.
2.6 Ground Conditions:
Information on the local and regional geology and hydrogeology was derived from databases
maintained by Geological Survey of Ireland (GSI); Teagasc Soil Maps and in-house data
obtained by OCM site investigations undertaken in the vicinity of the site in June 2009 and
May 2011.
2.6.1 Soils and Subsoil
The subsoils distribution, which is based on the Teagsc maps, is shown on Figure 2.2. The
soils across the site are classified as Made Ground i.e. fill material and concrete. The soils
in the lands surrounding the site are classified as Limestone Till (TLs). The OCM site
investigation confirmed the Teagasc classification.
Based on the borehole log for a well in the southeast of the site, the subsoil appears to be
approximately 2m thick beneath the facility. The lands to the east are approximately 1.5m
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lower and here the subsoil thickness increases from west to east, away from the facility
ranging from 0.4- 1.3m.
2.6.2 Bedrock
The site is underlain by undifferentiated Visean Limestone. The site investigation
encountered the top of bedrock, which is described as weathered and fractured dark grey to
black limestone.
2.7 Hydrogeology
2.7.1 Aquifer Classification
The GSI has developed a classification system for aquifers based on the value of the
resource and the hydrogeological characteristics. The bedrock aquifer beneath the site is
characterised by the GSI as a Regionally Important Karstified Aquifer (Rkc). Rkc denotes
the presence of limestone with conduit karst pathways for groundwater movement.
Typically, most of the groundwater flows in large open karstified fractures or conduits with
the remaining portion of the bedrock comprising massive limestone with little or no
groundwater movement. It is likely that the groundwater ultimately discharges to the
Carrowmonesh Stream catchment and into the sea at Oranmore.
2.7.2 Aquifer Vulnerability
The bedrock aquifer vulnerability, which is based on the type and thickness of the
subsoils, is Extreme along the eastern site boundary, but decreases to High
approximately 45m east of the site boundary.
2.7.3 Groundwater Flow Direction and Proximity to Wells
It is expected that the groundwater flow direction is to the southeast toward the
Carrowmonesh Stream. In the winter period, when the water table is close to or at the
surface, there may be a direct connection between the water table and the stream. Because
of the karst nature of the bedrock, it is difficult to predict the precise direction of flow
south of the site, but it is likely to initially flow to the south east and then change to the
west, discharging to Galway Bay at Oranmore.
A review of the GSI Well data identified a series of karst boreholes close to the coast at
Oranmore. There is no other on these features, and they may just be sink holes. One well
was also identified approximately 2km to the southeast of the site and is described as being
installed in 1927 for farm use. There are no other details on the well but, given its age, it is
unlikely to be in use.
2.7.4 Groundwater Dependant Terrestrial Ecosystems.
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There is a groundwater dependant terrestrial ecosystem GWDTE (wetland bog) to the east
of the Carrowmonesh Stream, approximately 800m southeast of the site. As the wetland is
primarily on the western side of the stream, it is likely that most of the groundwater input
comes from further east and south and it is unlikely groundwater moving beneath the site is
a significant source of recharge.
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3. OPERATIONAL AREA
3.1 External Yard & Paved Areas
The yard is used to stockpile unprocessed scrap metals, ELV, processed metals (ferrous and
non-ferrous), glass and tyres (rubber). In general the metals are not flammable or
combustible, however a hydrocarbon film that can be present on some of the metals is
flammable. The rubber tyres, which amount to approximately 40 tonnes at anyone time, are
combustible.
The yard is provided with perimeter kerbs that ranges in height from 300mm along the
southern and south western boundary to 200mm along the eastern boundary. The kerbing
prevents rainfall from flowing off the edge of the paved area. The fall is from north to south
and all run-off is directed to a single outfall at the southern boundary of the site.
3.2 Main Building
The building houses a series of units that are used for a variety of uses including – copper
wire stripping, storage of valuable metals, ELV depollution, vehicle maintenance and
workshop and offices. The de-pollution process is mainly mechanical, using gravity to drain
fluids from the vehicles into integral storage tanks. Waste oils from plant maintenance are
stored in bunded tanks inside the building pending removal offsite.
There are no internal drains in the building. Any firewater generated during a response to an
incident in any one of the units will flow south, out the doors serving the unit which are at a
higher level to the yard, and enter the surface water drainage system. As the rainwater run-off
from the building roof is directed to the drain at the southern boundary of the site, there is the
potential for some firewater run-off to enter the gullies.
3.3 Bunded Area
There is one oil bund located at the north eastern corner of the main building, which contains
three oil storage tanks (one 10m3 and two 3.5m3) and smaller drums and containers for
various engine and hydraulic oils. The area surrounding the bund is paved and any overspill
of firewater/foam will enter the surface water drainage system.
3.4 Car Park
The car park is at the northern site boundary and is not used for waste storage or processing.
Rainfall run-off from this area is separated from the runoff from the operational yard and
discharges to the drain at the southern boundary. The car park is not included in the
assessment, as there are no unique risks associated with this activity and it is up gradient of
any areas where incidents would result in the generation of firewater, could occur.
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4. FIRE CHARACTERISTICS OF PRODUCTS ON-SITE
4.1 Materials Classification
The majority of the wastes processed (metals) are not flammable, however some waste types
(for example tyres) and materials (diesel) are potentially combustible/flammable and harmful
to the environment. The only hazardous materials handled are diesel oil, and virgin and waste
fuel, lubricant and hydraulic oils and batteries recovered during the de-pollution of ELV.
The materials were classified using the Risk and Safety Phrases contained in Annex VI Table
3.2 of Regulation EC 1272/2008 on the Classification Labelling and Packaging of Substances
(CLP).
While the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
is phased the requirements for mixtures, do not come into effect until June, 2015 and many
product suppliers have to update their Materials Safety Data Sheets.
The relevant (R) phrase, where applicable, and the maximum quantities of fire sensitive
products stored on site at any one time are shown in Table 4.1 and 4.2.
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Table 4.1 – Volume of Hazardous Materials
Products Potential Quantity Stored (litre)
Diesel Oil 15,000
Waste Oils, Hydraulic Oil etc 7,000
Table 4.2 - Risk Phrase & Chemical Hazard
Material Hazard Description CAS No Risk Phrase
Rating
Hydraulic oil
32
This product and any contaminated soil
or water may be harmful to human,
animal, and aquatic life.
Mixture
64741 – 89 – 5
64741 – 88 – 4
64742 – 54 – 7
64749 – 42 - 3
NA
AFT –
(transmission
Fluid)
This material has no known health
hazards under applicable laws. Do not
discard to the environment.
Mixture
64742 – 54 - 7 NA
Waste Oils Harmful Carcinogenic Category 3.
Dangerous for the environment.
Mixture R45/R53
Diesel Harmful Carcinogenic Category 2.
Dangerous for the environment.
Mixture
68334-30-5
R40/R65/R66
/R51/R53*
Petrol Harmful Carcinogenic Category 3.
Dangerous for the environment.
Mixture
86290-81-5
R45/R46/R65
Brake Fluid
Avoid release to aquatic and terrestrial
environment. Will biodegrade rapidly
and should not bio accumulate.
Mixture R22/R36
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5. FIRE SAFETY MANAGEMENT SYSTEM
5.1 Fire Fighting Management System
The safety management system comprises:
• Fire prevention
• Fire containment
• Fire detection
• Fire suppression
• Response in event of fire
• Response in event of an alarm being raised
5.2 Fire Prevention Measures
5.2.1 Storage of Combustible and Flammable Materials
The following principles are applied to the storage of combustible materials and flammable
liquids.
• Good housekeeping and prompt transfer of wastes to prevent the build up of
combustible materials, in particular tyres.
• Regular inspection of plant and equipment for leaks and damage to prevent spillage of
flammable liquids.
• Removal of any gas containers or unidentified liquids/chemicals from the off-loading
areas to the quarantine area immediately such items are noticed.
5.2.2 Control of Sources of Ignition
The controls measures applied to minimise ignition sources include:
• No smoking policy
• Only authorised personnel are permitted within the waste handling areas
• Secure site access to prevent unauthorised entry
5.2.3 Safety Audits
Internal safety audits are carried out quarterly.
5.3 Fire Detection
The fire detection system/alarm mechanisms include;
• Office building fire alarm system
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• Office building smoke detection system
• Site staff who well alert other staff members in the event of a fire,
• 24 hour security
• The Facility Manager and Environmental Manager are the designated Site Incident
Controllers, with responsibility for assessing the scale of an incident and, alerting the
fire service.
5.4 Fire Suppression
The on site fire abatement equipment includes: �
• Fire Extinguishers – 8 No located at strategic points around the facility
• Fire Fighting Water Supply – 2 No. Hydrants present in the yard area and one outside
the site boundary that is accessible
In the event of an emergency call out, Galway City Fire Service tenders will bring water to
site. The volume of water varies depending on number of tenders or tankers. Normally
approximately 2 fire tenders with 1.82m3 capacity each are dispatched to an incident at a
facility such as this.
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6. FIRE WATER RISK ASSESSMENT
Risk Assessment is defined in the Draft Guidelines as ‘an assessment of the risk that an
industrial facility poses to the environment during a fire that brings fire-water into contact
with operations or substances that would cause significant pollution’. Contaminated fire-
water is defined as ‘water that has become contaminated with process materials used at a
facility and the products resulting from combustion’.
The review of site operations identified one discrete drainage area for risk assessment
purposes. This comprises the kerbed paved yard used for storage and processing of metals,
which drains to one discharge point. Firewater run-off generated in a response to an incident
at other potential locations of fire outbreak including the fuel storage areas the waste oil
storage tanks and waste activities inside the main building- will all run-off onto the yard.
In the event of a fire in the main building, there is the potential for firewater run-off to enter
the gullies that are connected to the storm sewer that discharges to the drain.
6.1 Potential Fire Load Criteria
The potential fire load is determined by the type of combustible materials present and the
likely rate of combustion. The criteria used in this assessment are set out in Table 6.1.
Table 6.1 Fire Load Criteria
Low Load Quantities of poorly combustible material
Medium Load Significant quantities of combustible materials
High load Substantial quantity of combustible materials, or large quantity of flammable
liquids
6.2 Fire Risk Criteria
The fire risk criteria are:
• Risk of ignition
• Risk of non-detection
• Risk of failure to extinguish correctly/quickly
The risk of ignition is lowest where there are no flammable or highly flammable materials,
such as liquids or gases present, or where they are present only in small quantities.
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The risk of non-detection is highest in an area that is unoccupied/unmonitored for a prolonged
period of time and when there is no automated fire detection system.
The risk of failure to extinguish a fire quickly and fully is dependant on quick detection and
appropriate fire extinguishing techniques. If detected promptly and the appropriate corrective
action taken, then the fire risk is considered to be Low. If a fire is not likely to be detected
quickly, the fire risk is considered to be Medium. The Fire Risk Categories used in this
assessment are set out in Table 6.2.
Table 6.2: Fire Risk Categories
Low Risk Where fire is an unlikely risk
Medium Risk Where fire is a possible risk
High Risk Where a fire has feasible potential
6.3 Environmental Load
The environmental load is an assessment of the likelihood of environmental impacts to
surrounding soils, air, surface and groundwater. The severity of the impacts depends on the
characteristics and quantities of materials on-site at the time of a fire that have the potential
for significant degradation of the receiving environmental media. The main assessment
criteria include:
• BOD
• Acute toxicity effects
• Persistence of the pollutant
• Risk of bio-accumulation �
The Environmental Load Criteria are set out in Table 6.3.
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Table 6.3 Environmental Load Criteria
Low Load Minor potential for degradation of receiving air/soil/water
Medium Load Potential for minor degradation and/or long term effects to receiving
soils/waters
High Load Potential for major degradation and long term effects to receiving
air/soil/water
6.4 Environmental Risk Criteria
The assessment of the environmental risk presented by a fire is based on a combination of the
risk and extent of a fire, the environmental load and the area at risk. The latter includes:
• The extent of air/soil/water polluted
• Use of receiving air/soil/water (crop production, potable water, livestock, water
irrigation, fishing, wetlands/wildlife habitat or public amenity use)
The Environmental Risk Criteria used in this assessment are presented in Table 6.4.
Table 6.4 Environmental Risk Criteria
Low Risk Not a significant risk, protective measures may be required in the long term
Medium Risk Discernible risk, where proactive remedial works or protective works may be
required
High Risk Extremely hazardous risk of significant environmental degradation and
preventative action is required immediately
6.5 Risk Assessment
Volumes of Firewater
Rainfall on the yard flows from north to south and is collected in the surface water drainage
system before discharge to the foul sewer. The out flow from the attenuation tank is restricted
to a maximum of 4l/seconds.
The most significant fire risk, with consequent generation of firewater run-off, is associated
with the stockpiled waste tyres, plant items and some of the metals that can be coated with
hydrocarbons. These stockpiles are kept separate and the size is minimised. The maximum
amount of tyres on site at any one time is 40 tonnes.
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There is a lesser risk of a fire occurring at the oil storage areas. If this occurs, fire suppressant
foam will be used in the response, the majority of which will be contained within the bunds,
with any over spill entering the drainage system serving the yard. If there is an explosion or
rupture to the tanks that damages the bunds, the contents of the tanks and suppressant foam
will enter the drainage system.
The likely firewater volume arising due to a fire at the metal, plant or tyre stockpiles is shown
in Table 6.5. The Draft Guidance assumes a fire will last 45 minutes, however OCM has
assumed the fire could last or 90 minutes. The estimated volume is 219.64m3, excluding
rainfall.
However, account must also be taken of a significant rainfall event on the day of the fire. The
Draft Guidance specifies a rainfall event of at least 50mm over the entire area served by the
surface water drainage system. The volume of water generated by a rainfall event of this
magnitude is 503.5m3 (area served by drainage system 10,070m2 x 0.05m).
Rainfall on the car park can be discounted as this is directed to a separate discharge point and
does not enter the yard.
Table 6.5 – Yard
Parameter Calculation
Area 10,070 m2
Containment (in the surface water
drainage system (pipe work, silt traps,
interceptors) 0 m3
Containment on the paved area,
retained by existing kerbing and by
attenuation tank 790 m3
Available containment 790 m3
Tender Vehicle Capacity x 2 3.64 m3
Time of Fire 1.5 hours
Water Hydrant Delivery -
20litres/second/hydrant (2 No) 216 m3/hour
Firewater (3.64m3 + 216m3) 219.64 m3
Potential Rainfall - 0.05m (30yr
event) x 10,070m2 x 1 (Paved100%)3 503.5 m3
Total To be Retained 723.14 m3
Destination
In the event of a fire the vast majority firewater runoff will enter the drainage system serving
the yard. The retention capacity in the south of the site, which is provided by the kerb, in
conjunction with the attenuation tank provides a total storage capacity of 790m3. In the case
of a fire in the main building there is the potential for small volumes to enter the gullies that
take the roof water and which discharge to the drain.
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The existing storage capacity exceeds the amount generated in the fire and includes for ~50m3
that could be present in the system before the fire. Given the continuous outfall from the
attenuation tank, this is a conservative assumption.
Fire Load
The potential Fire Load is considered to be High due to quantity and types of the waste and
materials stored.
Fire Risk
The Fire Risk is Medium. Sources of ignition are limited and confined to fixed (shearing
plant) and mobile plant (forklifts). The majority of the wastes are not flammable, but
flammable hydrocarbons can coat some of the metals and the tyres are combustible. The fire
fighting management plan and fire fighting equipment provided facilitate the control of most
fires within a short period of time.
Environmental Load
The potential environmental load is High. The contaminant potential of the materials stored
onsite is considered High due to the ecotoxic nature of some of the hydrocarbons used and
stored at the facility and combustion residues from the tyres, which have the potential to be
contained in the firewater run-off.
Environmental Risk
The overall environmental risk associated with a fire is considered Medium given the limited
volumes that could be discharged to the foul sewer (4l/s) and to the surface water drain at the
south of the site. The existing storage capacity eliminates the risk of overtopping of the bund
along the southern boundary and the release of firewater to the unpaved ground and the
surface water drain.
Retention Requirement
A fire during a 50mm rainfall event would generate 723m3 of firewater. The existing surface
water drainage system serving the operational areas where a fire could occur has a storage
capacity of 790m3, all of which can be retained in the existing surface water drainage system.
However at present there is a continuous outfall from the attenuation tank to the foul sewer.
As the risks associated with the Fire Load and Environmental Load are considered High,
measures to minimise risk are required. The existing risk management programme, which is
described in Section 5, and the provision of shut off-valves at the outlet from the attenuation
tank and on the storm sewer that takes run-off from the main building will mitigate the risk.
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6.6 Source-Pathway-Receptor Risk Assessment
Risk assessment is a scientific mechanism, which allows the various hazards, pathways and
receptors present at a site to be evaluated. It uses a systematic and progressive approach in
identifying the risks at a site with the aim of establishing a pollutant linkage from a hazard via
a pathway to a receptor. If a pathway does not exist linking the hazard to a receptor, then the
risk is absent.
The pathways by which contaminated firewater can migrate from the site are
• Surface water drainage system,
• Infiltration through the yard to ground
• Overland flow across site boundary
The potential receptors are:-
• Surface Water Body (Receiving drain and the Carrowmonesh Stream),
• Groundwater Aquifer
• Neighbouring industrial/commercial premises
• Municipal Wastewater Treatment Plant
In the event of a fire there is the likelihood that hydrocarbon contaminated (ecotoxic)
firewater will be generated (Source). There are no pathways to groundwater and the
neighboring facilities. There is a pathway to the municipal wastewater treatment plant. The
provision of a shut-off valve on the storm sewer that takes run-off from the building roof
would eliminate the pathway to surface waters. Similarly the installation of a shut-off valve
at the outlet from the attenuation tank would eliminate the pathway to the foul sewer.
Following a fire the retained contaminated firewater can be sampled and depending on the
results and with the agreement of Irish Water released to the foul sewer or removed from the
site using road tankers and sent to authorised waste treatment facilities.
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7. CONCLUSIONS
7.1 Conclusions
• The risk of fire is generally Medium due to minimisation measures implemented by
Galway Metals and the types of materials stored onsite.
• The potential environmental impacts from an uncontrolled release of firewater are
Medium due to the limited volumes of firewater that could enter the foul sewer.
• The quantities of on site materials with risk phrases R50, R51, R52 and R53 are low,
only diesel (R53) is present onsite in significant quantities. Although R53 is used the
volumes are significantly below the threshold (>1000 tonnes) specified in Section I of
Appendix A of the Agency Draft Guidance Note that would require a dedicated
retention facility.
• At present, there is the potential for contaminated firewater to discharge to the foul
sewer at a rate of 4l/s.
7.2 Recommendations
• It is recommended that shut off valves be installed at the outlet from the attenuation
tank and on the storm sewer that takes run-off from the building roof.
• It is recommended that the Emergency Response Plan be updated to reflect the
findings of this assessment. In particular, a requirement to close the shut off valves in
the event of a fire.
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APPENDIX 1
Site Layout & Drainage Drawing
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APPENDIX 2
Drainage Calculations
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Project
Galway Metal Company Limited Job Ref.
051800 Section
Upgrading Foul & Surface Water Design Sheet no./rev
Calc. By
D.T./P.F.
Date
May’14
Chck’d by
P.F.
Date
May’14
App’d by
P.F.
Date
May’14
Domestic Waste water details of how the P.E. & DWF were calculated. Population Equivalent (p.e.) = 14 Maximum employees on site = 35 Flow given as 35 x 60l/day = 2100l/day BOD5 60l/day = flow litres/day/ per person as per Environmental Protection Agency Wastewater Treatment Manuals Treatment Systems for Small Communities, Business, Leisure Centres and Hotels Table 3: Recommended wastewater loading rates from an industrial commercial premises with office and/or factory with canteen. Expected Dry Weather Flow (DWF) 2.1 m3/day. Population Equivalent The pollution loading from domestic effluents should be expressed in terms of the pollution loading generated by an equivalent domestic population, referred to as the population equivalent (p.e.). 2100 l/day divided by 150 litres /person/day = 14 people. Dry Weather Flow For domestic effluents flow is expressed in terms of dry weather flow (DWF). DWF is expressed as litres/person/day and is typically given as 150 litres /person/day The domestic effluent DWF is calculated as 2100 l/day. Trade Waste water Existing Site Drainage. The surface water drainage on site is constructed in a manner which allows for the separation of the run-off from the buildings from the run-off from the yard. It is proposed that the surface water drainage from the building and car park area will continue to discharge from the site in the existing arrangement. The only area to discharge to the foul sewer shall be the working yard area. The drainage from the yard is collected in channels at the surface and is conveyed through large silt traps and is subsequently treated in a full retention separator . It is proposed that the discharge from the separator will collected and attenuated before pumping to the public sewer. The area of the site is 1.35 Ha. The area of the yard to be drained is 1.07 Ha.
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Project
Galway Metal Company Limited Job Ref.
051800 Section
Upgrading Foul & Surface Water Design Sheet no./rev
Calc. By
D.T./P.F.
Date
May’14
Chck’d by
P.F.
Date
May’14
App’d by
P.F.
Date
May’14
Proposed Design of Attenuation We have evaluated three options available for the design of the attenuation. The first is based on formulae derived from the Bilham equation. The second is based on BRE Digest 365 and the third is based on site specific data from Met Eirann which give period rainfall depths (mm) for sliding durations. Of the methods investigated, the Met Eireann figures (attached) were used as they are site specific and the results are slightly more conservative than the other methods. We have adopted a return period of 1 in 100 years for a storm event. After Detailed Discussions with John McMyler Galway County Council. An agreed max. Flow of 4 L/sec was agreed. This gives a maximum storage of 754 m³. To accommodate this level of attenuation, an over ground attenuation tank on a strip of ground adjacent to the existing yard has been constructed. This tank has a storage volume of 401 m³. The balance of the storage requirement (754 - 401 = 353 m³) can be accommodated in the existing yard. The attached drawing shows an area hatched yellow which can be temporarily used for storage in extreme events. The hatched area will fill to an average depth of 180mm. The bunded area is 3100 m². The volume of storage available in this area may be reduced by scrap storage. Applying a 30% reduction in the available volume gives potential storage of (3100 * 0.18 * 0.7 = 391 m³) The combined storage of the tank and yard attenuati on is (400 + 391) 791 m³. This exceeds the volume required for a 100 year event with a 4 l/sec max di scharge (754 m³). To assess the volume of effluent which is discharged to the public sewer, we have evaluated the volume of effluent which would have contributed to the County Council sewer in a 12 month period from 09/2011 to 08/2012. The attached table identifies rainfall amounts for each day of the year. These figures need to be read in conjunction with the area of the hard standing and the rate of evapotranspiration. To establish the rate of evapotranspiration we used the Penman formula. This gives rates of PE ranging from 15mm in January to 840mm in July. These figure are however misleading as there will be no transpiration from the site and the runoff is to be stored in a covered underground tank. Evaporation will come from the yard & the surfaces of the scrap heap. The approach we have adopted is give an estimation of rates of actual evaportation across the 12 months. This scale categorises the months as follows;
Month Evaporation/day (mm) January 0.0 February 0.0 March 1.0 April 1.5 May 3.0 June 3.0 July 3.0 August 3.0 September 1.5 October 1.0 November 0.0 December 0.0
The effect of the application of these factors is to reduce the total rainfall from 1100mm to 845mm /annum.
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EPA Export 13-09-2016:01:49:24
Project
Galway Metal Company Limited Job Ref.
051800 Section
Upgrading Foul & Surface Water Design Sheet no./rev
Calc. By
D.T./P.F.
Date
May’14
Chck’d by
P.F.
Date
May’14
App’d by
P.F.
Date
May’14
The table below identifies total rainfall for each month along with the number of dry days and a record of the wettest day. It can be seen that there are 175 days in the 12 month period where there was no discharge to the sewer.
Monthly summary of Oranmore rainfall
Month Total
Rainfall (mm)
Total Rainfall - evaporation
mm
Number of days with no
discharge
Highest Daily
Rainfall mm
Sep-11 119.3 87.6 13 16.7 Oct-11 135 109.8 7 16.8
Nov-11 136.6 136.6 8 29.6 Dec-11 133.6 133.6 1 9.4 Jan-12 100.8 100.8 7 11.8 Feb-12 43.2 43.2 4 8.8 Mar-12 27.6 18.8 25 7 Apr-12 55 32.9 21 10.7 May-12 49.6 25 27 10.6 Jun-12 114.6 68 19 17.8 Jul-12 92.6 47.4 23 14.6
Aug-12 94.2 41.2 20 8.2
The peak discharge for the year came on the 29th Nov. This recorded 29.6mm rainfall. The table below is taken from the automatic weather station in Oranmore. It gives the cumulative rate of rainfall over the 24 hour period. Based on this information we have prepared a graph identifying the maximum volume of storage required in the attenuation tank (see attached). The relationship between rainfall & volume of storage is as follows; The area contributing to the attenuation tank is 1.07 Ha. For every 1mm of rain that falls on site there will be ~ 10cu.m to be discharged. This identifies that on the given date a maximum storage of 85 cu.m is required just before 2 am. In our proposal to the County Council we are proposing a tank of 400 cu.m.
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EPA Export 13-09-2016:01:49:24
Project
Galway Metal Company Limited Job Ref.
051800 Section
Upgrading Foul & Surface Water Design Sheet no./rev
Calc. By
D.T./P.F.
Date
May’14
Chck’d by
P.F.
Date
May’14
App’d by
P.F.
Date
May’14
In conclusion it can be seen that the 12 month period had precipitation of 1100mm, which is close to the average. For nearly 50% of the year there will be no discharge to the foul sewer. On average the remaining wet days will contribute 4.7 cu.m . The proposed attenuation system would have comfortably dealt with the rainfall conditions
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EPA Export 13-09-2016:01:49:24
Project
Galway Metal Company Limited Job Ref.
051800 Section
Upgrading Foul & Surface Water Design Sheet no./rev
Calc. By
D.T./P.F.
Date
May’14
Chck’d by
P.F.
Date
May’14
App’d by
P.F.
Date
May’14
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EPA Export 13-09-2016:01:49:24
Project
Galway Metal Company Limited Job Ref.
051800 Section
Upgrading Foul & Surface Water Design Sheet no./rev
Calc. By
D.T./P.F.
Date
May’14
Chck’d by
P.F.
Date
May’14
App’d by
P.F.
Date
May’14
Connection to the Existing Foul Sewer From the attenuation tank a pair of duty and standby pumps is installed to provide a max flow of 4 l/s. This flow is metered and a display cabinet is provided in the pump house. In addition to the flow from the yard, Galway Metal have also to connected the foul effluent from their offices. The volume of this effluent is approximately 1.5 cu.m /day . The attached drawing shows the existing drainage being picked up in a 150mm foul sewer constructed at a gradient of 1 in 150. This has a capacity of 15 l/s. The rising main from the attenuation tank discharges to the head manhole.
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GALWAY METAL . PROPOSED DISCHARGE TO FOUL SEWER
STORAGE VOLUMES REQUIRED FOR 1 IN 100 YEAR EVENT FOR VARYING OUTFLOW RATES
INFLOW RATES DERIVED FROM MET EIREANN RETURN RAINFALL DEPTHS FOR SLIDING DURATIONS FOR THE ORANMORE AREA
Depth(mm)/Return Period 4l/s outflow 100 year return 7l/s outflow 100 year return 10l/s outflow 100 year return 15l/s outflow 100 year return
DURATION, 30 years 100 years inflow outflow Storage inflow outflow Storage inflow outflow Storage inflow outflow Storage5 5 mins, 9.7 12.6 134.82 1.2 133.62 134.82 2.1 132.72 134.82 3 131.82 134.82 4.5 130.32
10 10 mins, 13.6 17.5 187.25 2.4 184.85 187.25 4.2 183.05 187.25 6 181.25 187.25 9 178.2515 15 mins, 16 20.6 220.42 3.6 216.82 220.42 6.3 214.12 220.42 9 211.42 220.42 13.5 206.9230 30 mins 20.5 26.3 281.41 7.2 274.21 281.41 12.6 268.81 281.41 18 263.41 281.41 27 254.4160 1 hours 26.4 33.5 358.45 14.4 344.05 358.45 25.2 333.25 358.45 36 322.45 358.45 54 304.45
120 2 hours 34 42.8 457.96 28.8 429.16 457.96 50.4 407.56 457.96 72 385.96 457.96 108 349.96180 3 hours 39.4 49.4 528.58 43.2 485.38 528.58 75.6 452.98 528.58 108 420.58 528.58 162 366.58240 4 hours, 43.7 54.6 584.22 57.6 526.62 584.22 100.8 483.42 584.22 144 440.22 584.22 216 368.22360 6 hours, 50.7 63 674.1 86.4 587.7 674.1 151.2 522.9 674.1 216 458.1 674.1 324 350.1540 9 hours, 58.7 72.7 777.89 129.6 648.29 777.89 226.8 551.09 777.89 324 453.89 777.89 486 291.89720 12 hours, 65.2 80.5 861.35 172.8 688.55 861.35 302.4 558.95 861.35 432 429.35 861.35 648 213.35
1080 18 hours, 75.6 92.9 994.03 259.2 734.83 994.03 453.6 540.43 994.03 648 346.03 994.03 972 22.031440 24 hours 84 102.8 1099.96 345.6 754.36 1099.96 604.8 495.16 1099.96 864 235.96 1099.96 1296 -196.042880 2 days, 100.1 121 1294.7 691.2 603.5 1294.7 1209.6 85.1 1294.7 1728 -433.3 1294.7 2592 -1297.34320 3 days, 113.5 136.1 1456.27 1036.8 419.47 1456.27 1814.4 -358.13 1456.27 2592 -1135.73 1456.27 3888 -2431.735760 4 days, 125.4 149.5 1599.65 1382.4 217.25 1599.65 2419.2 -819.55 1599.65 3456 -1856.35 1599.65 5184 -3584.358640 6 days, 146.3 173.1 1852.17 2073.6 -221.43 1852.17 3628.8 -1776.63 1852.17 5184 -3331.83 1852.17 7776 -5923.83
11520 8 days, 164.9 194.1 2076.87 2764.8 -687.93 2076.87 4838.4 -2761.53 2076.87 6912 -4835.13 2076.87 10368 -8291.1314400 10 days, 182 213.3 2282.31 3456 -1173.69 2282.31 6048 -3765.69 2282.31 8640 -6357.69 2282.31 12960 -10677.717280 12 days, 198.1 231.3 2474.91 4147.2 -1672.29 2474.91 7257.6 -4782.69 2474.91 10368 -7893.09 2474.91 15552 -13077.123040 16 days, 227.9 264.6 2831.22 5529.6 -2698.38 2831.22 9676.8 -6845.58 2831.22 13824 -10992.8 2831.22 20736 -17904.828800 20 days, 255.6 295.5 3161.85 6912 -3750.15 3161.85 12096 -8934.15 3161.85 17280 -14118.2 3161.85 25920 -22758.236000 25 days 288 331.6 3548.12 8640 -5091.88 3548.12 15120 -11571.9 3548.12 21600 -18051.9 3548.12 32400 -28851.9
SITE AREA = 1.35 HA.AREA TO BE DRAINED = 1.07 Ha.
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STORAGE VOLUMES REQUIRED FOR 1 IN 30 YEAR EVENT FOR VARYING OUTFLOW RATES
INFLOW RATES DERIVED FROM MET EIREANN RETURN RAINFALL DEPTHS FOR SLIDING DURATIONS FOR THE ORANMORE AREA
4l/s outflow 30 year return 7l/s outflow 30 year return 10l/s outflow 30 year return 15l/s outflow 30 year returnReturn Period
DURATION, 30 years 100 years inflow outflow Storage inflow outflow Storage inflow outflow Storage inflow outflow Storage5 5 mins, 9.7 12.6 103.79 1.2 102.59 103.79 2.1 101.69 103.79 3 100.79 103.79 4.5 99.29
10 10 mins, 13.6 17.5 145.52 2.4 143.12 145.52 4.2 141.32 145.52 6 139.52 145.52 9 136.5215 15 mins, 16 20.6 171.2 3.6 167.6 171.2 6.3 164.9 171.2 9 162.2 171.2 13.5 157.730 30 mins 20.5 26.3 219.35 7.2 212.15 219.35 12.6 206.75 219.35 18 201.35 219.35 27 192.3560 1 hours 26.4 33.5 282.48 14.4 268.08 282.48 25.2 257.28 282.48 36 246.48 282.48 54 228.48
120 2 hours 34 42.8 363.8 28.8 335 363.8 50.4 313.4 363.8 72 291.8 363.8 108 255.8180 3 hours 39.4 49.4 421.58 43.2 378.38 421.58 75.6 345.98 421.58 108 313.58 421.58 162 259.58240 4 hours, 43.7 54.6 467.59 57.6 409.99 467.59 100.8 366.79 467.59 144 323.59 467.59 216 251.59360 6 hours, 50.7 63 542.49 86.4 456.09 542.49 151.2 391.29 542.49 216 326.49 542.49 324 218.49540 9 hours, 58.7 72.7 628.09 129.6 498.49 628.09 226.8 401.29 628.09 324 304.09 628.09 486 142.09720 12 hours, 65.2 80.5 697.64 172.8 524.84 697.64 302.4 395.24 697.64 432 265.64 697.64 648 49.64
1080 18 hours, 75.6 92.9 808.92 259.2 549.72 808.92 453.6 355.32 808.92 648 160.92 808.92 972 -163.081440 24 hours 84 102.8 898.8 345.6 553.2 898.8 604.8 294 898.8 864 34.8 898.8 1296 -397.22880 2 days, 100.1 121 1071.07 691.2 379.87 1071.07 1209.6 -138.53 1071.07 1728 -656.93 1071.07 2592 -1520.934320 3 days, 113.5 136.1 1214.45 1036.8 177.65 1214.45 1814.4 -599.95 1214.45 2592 -1377.55 1214.45 3888 -2673.555760 4 days, 125.4 149.5 1341.78 1382.4 -40.62 1341.78 2419.2 -1077.42 1341.78 3456 -2114.22 1341.78 5184 -3842.228640 6 days, 146.3 173.1 1565.41 2073.6 -508.19 1565.41 3628.8 -2063.39 1565.41 5184 -3618.59 1565.41 7776 -6210.59
11520 8 days, 164.9 194.1 1764.43 2764.8 -1000.37 1764.43 4838.4 -3073.97 1764.43 6912 -5147.57 1764.43 10368 -8603.5714400 10 days, 182 213.3 1947.4 3456 -1508.6 1947.4 6048 -4100.6 1947.4 8640 -6692.6 1947.4 12960 -11012.617280 12 days, 198.1 231.3 2119.67 4147.2 -2027.53 2119.67 7257.6 -5137.93 2119.67 10368 -8248.33 2119.67 15552 -13432.323040 16 days, 227.9 264.6 2438.53 5529.6 -3091.07 2438.53 9676.8 -7238.27 2438.53 13824 -11385.5 2438.53 20736 -18297.528800 20 days, 255.6 295.5 2734.92 6912 -4177.08 2734.92 12096 -9361.08 2734.92 17280 -14545.1 2734.92 25920 -23185.136000 25 days 288 331.6 3081.6 8640 -5558.4 3081.6 15120 -12038.4 3081.6 21600 -18518.4 3081.6 32400 -29318.4
SITE AREA = 1.35 HA.AREA TO BE DRAINED = 1.07 Ha.
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