HydroChamber Design Manual. LSW HydroChamber. Stormwater Management System Design Manual

Transcription

1 LSW HydroChamber Stormwater Management System Design Manual

2 1.0 Introduction 1.1 General 1.2 Conventional Systems 1.3 Application (Infiltration) 1.4 Application (Attenuation) 2.0 Product Description 2.1 HydroChamber HC HydroChamber End Caps 2.3 Ancillary Components 3.0 Structural Design 3.1 General 3.2 Field Testing HydroChamber Design Manual Table of contents 4.0 System Selection 4.1 Infiltration 4.2 Infiltration with controlled discharge 4.3 Attenuation 5.0 Infiltration 5.1 Hydraulic Operation 5.2 Infiltration Design 5.3 Installation 6.0 Attenuation 6.1 Hydraulic Operation 6.2 Attenuation Design 6.3 Installation 7.0 Foundation Design 8.0 Invert Levels and Falls 8.1 Infiltration Systems 8.2 Permeable Attenuation Systems 8.3 Impermeable Attenuation Systems 9.0 Cover Levels and Depths 9.1 Backfill Tables 10.0 Alternative Inlet / Outlet Arrangements 11.0 Geotextiles, Geomembranes and Liners Separator / Filter Geotextile Protector Geotextile High Flow Filter Geotextile PVC Geomembrane Geosynthetic Clay Liner 12.0 Venting Manhole Covers 13.0 Inspection / Maintenance 13.1 General 13.2 Inspection 13.3 Maintenance

3 Introduction 1.1 General The HydroChambers stormwater management system was developed to satisfy engineers, architects, local authorities and contractors. It is a unique design that is capable of withstanding HGV traffic loads and has a very effective silt management system. The HydroChambers can be used for infiltration and attenuation depending on the application. Fig Flooding 1.2 Conventional Systems Rainfall on a green field site is either absorbed into the ground or runs off slowly to the nearest watercourse. When these sites are built upon, much of the area becomes impermeable increasing surface water runoff which is piped to the nearest outfall or storm drain. This increased run-off coupled with global climate changes have caused large scale flooding in many areas, with conventional storm water drainage systems being over-loaded. 1.3 Application Infiltration Where possible it is recommended to disposes of the stormwater on site through infiltration. This allows the stormwater to replenish the natural water table as would have happened before the site was developed. Over time this allows a natural biomass to form on the walls and floor of the tank, this filters and helps break down pollutants and contaminants that may be found in stormwater runoff. Using this type of system the excavation is lined in a permeable non-woven geotextile (see table 9.2) which allows the water infiltrate vertically and laterally into the surrounding ground (see section 5). A detailed site audit is required to determine if infiltration is suitable and should be carried out by the consultant engineer. The audit should include analysis of the following parameters: site topography, winter water table level, soil type, soil infiltration rate, soil contamination and local authority regulations. (see section 4) 1.4 Application Attenuation Attenuation tanks control the rate at which stormwater enters the local water course or storm drain. They can be sealed or permeable systems depending on site conditions. The flow is controlled with a Hydro-Valve vortex flow control device. A detailed site audit is required to determine if the tank should be sealed or permeable and should be carried out by the consultant engineer. The audit should include analysis of the following parameters: site topography, winter water table level, soil type, soil infiltration rate and local authority regulations. 1 of 19

4 2.0 Product Description 2.1 HydroChamber HC-800 The HydroChamber is a thermoplastic culvert manufactured from high density polyethylene. The chambers hold a nominal capacity of 1.40m³, the system (chambers and backfill stone) holds a nominal storage capacity of 2.3m³ per chamber when installed with 300mm of 35-50mm clean washed crushed stone in the foundation. A stone porosity of 40% is assumed and can change depending on compaction and aggregate particle size. The arch shape of the chamber and the corrugated wall profile provides optimum structural strength (see section 3). There is an integrated inspection port in each chamber as detailed in section 11. This port 2.2 may HydroChamber used to lower End a silt Cap detection HCprobe 800-EC into the chamber to check the level of The silt HydroChamber and to see is if a maintenance high density is required. polyethylene Alternatively stormwater inspection chamber can be carried out through the Ø600mm inlet / outlet pipe. HC-800 Specifications Overall Dimensions (mm): 2325 X 1250 X 800 Installed Dimensions (mm): 2175 X 1250 X 800 Nominal Storage / Chamber:1.40m³ System Storage*: Lateral Flow : 2.3m³ / Chamber 114 Holes Ø20mm * System storage is based on 300mm of 35-50mm clean washed crushed foundation stone with 150mm over and around each chamber with an assumed void ratio of 40%. Fig 2.1 HydroChamber The HydroChambers are assembled together with the last end rib of the first chamber fitting over the first end rib of the next chamber. This assembly method can be used to create a row of chambers any length. Each end of the row is protected from the backfill material by an end cap as shown in the next section. Any number of rows can be placed side by side with a 150mm space between adjacent chambers The chambers are backfilled with 35-50mm clean washed crushed angular stone. It is important that the stone is washed so the fines do not settle in the base of the tank. This may reduce the soakaway rate in an infiltration tank. The stone may need to be compacted depending on the application trafficked or non-trafficked. (See section 7 for more details). 2of 19

5 2.2 HydroChamber End Caps HC-800-EC There are three end caps used in conjunction with the HydroChamber. All End Caps are manufactured from medium density polyethylene. The end caps are designed to fit under any rib in the HydroChamber. During installation all end caps are screwed to the HydroChamber in three to four evenly spaced places along the perimeter of the arch. The units are lightweight and can be easily installed by one person. HC800-EC01 HC800-EC02 HC800-EC03 Fig 2.2 HydroChamber End Caps HC800-EC HC800-EC03 This end cap has six eccentric protruding circles of standard pipe sizes including 225, 300, 375, 450, 525 and 600mm. Each of these circles can be cut out to allow a pipe connection to form a manifold HC800-EC02 This end cap has a ribbed domed design and can be used to blank off all rows of chambers with no pipe connections. This end cap has connection for a 600mm twin wall HDPE drainage pipe. The end cap is designed so that the invert on the 600mm inlet / outlet pipe is in line with the foundation stone which provides an even transition from pipe to stone. This end cap is installed on the silt collection row to allow access (Ø600mm) for inspection and maintenance. 3of 19

6 2.3 Ancillary Components The following components are used in conjunction with the HydroChamber and HydroChamber End Caps to create a complete infiltration or attenuation system. Inlet / outlet Pipe - CorriPipe Vent pipe - CorriPipe Non Woven Geotextile High Flow Filter Geotextile Geosynthetic Cay Liner Impermeable Geomembrane PVC Membrane Hydro-Valve (attenuation only) Hydro Seal (impermeable system only) Fig 2.4 Ancillary Components 4of 19

7 3.0 Structural Design 3.1 General The structural design of the HydroChamber was developed using advanced 3D non-linear finite element analysis (Ansys). The analysis was carried out in a state of the art R&D facility with consultancy from specialised third parties. Numerous geometries were analysed until the optimal design for the expected dead and live loads was reached. The design calculations considered short term and long term loading scenarios and safety factors. Figure 3.1 Finite Element Analysis 3.2 Field Testing A unique test specification was developed in conjunction with the BBA and WRc to establish dead and live load capabilities both short term and long term. The chambers were tested in a live field test and were independently witnessed by the BBA and WRc. The tests used state of the art instrumentation including LVDT s, strain gauges, data loggers, temperature sensors, soil pressure cells etc. Short term tests were carried out to establish minimum cover depths and maximum traffic loads. A safety factor of 4 was established during these tests for table 9.0 in section 9. Figure 3.2 Instrumentation Setup Figure 3.3 Instrumentation Installation Long term loading was carried out to calculate the rate of creep under a deep burial of 2.4 meters cover. This was extrapolated to give a design life. The HydroChamber system is suitable for use in green areas and lightly trafficked areas with occasional HGV traffic e.g. car park. See table 9.0 for more details. Figure 3.4 HGV Loads 5of 19

8 4.0 System Selection When designing a sustainable stormwater management system there are three different options available to the designer. 4.1 Infiltration System This is a permeable system with all the storm water infiltrating into the ground through an underground storage / soakaway system with no outfall. Infiltration should always be the first option considered. 4.2 Permeable Attenuation System This is an infiltration system with a controlled discharge to the local watercourse or storm drain. The outlet provides an added factor of safety for long term sustainability. 4.3 Impermeable Attenuation System This is a fully sealed system preventing the groundwater entering the tank and the stormwater entering the soil. Usually used in areas with a high water table. System Selection No Is the position of the tank and the site topology suitable for Infiltration Yes No Is the winter water table 600mm or more below the invert of the tank? Yes Is the winter water table 1 metre or more below the invert of the tank? No Yes Yes Is the Soil Contaminated? No Is the Soil Suitable for Infiltrat ion No Yes Sizing calculations based on the modified rational method or similar approved and pre development runoff rate. Sizing calculations based on the CIRIA Report 156 Infiltration Drainage Manual of Good Practice or the BRE Digest 365. Sizing calculations based on the modified rational method or similar approved and pre development runoff rate. Impermeable Attenuation Tank Sealed system with controlled discharge to watercourse or storm drain Infiltration Tan k Permeable System with discharge to ground only Permeable Attenuation Tank Permeable system with controlled discharge to watercourse or storm drain. 6of 19

9 5.0 Infiltration 5.1 Hydraulic Operation During a rainstorm event all stormwater is piped into the catchpit manhole where heavy solids and floatables are trapped. It then flows through the inspection manhole into the silt collection row of HydroChambers which is wrapped in a layer of woven high flow filter geotextile. The water leaves the silt collection chamber vertically through the foundation stone and laterally through the holes in the side of each chamber. Any light silt, that passed through the catchpit manhole is trapped in the silt collection row by the geotextile filter. Once the water leaves the silt collection row it runs through the foundation and backfill stone into the Adjacent chambers and infiltrates though the separator / filter layer of non-woven geotextile into the surrounding ground. 5.2 Infiltration Design The required size for the HydroChamber infiltration tank will be determined from the following parameters after a detailed site audit - analysis of the following parameters: site topography, winter water table level, soil type, soil infiltration rate, soil contamination and local authority regulations. The calculations should be based on either CIRIA Report 156 Infiltration Drainage or the BRE Digest 365. (See section 4) Fig.5.1 Infiltration / Soakaway Layout (installation shown under green area) 7of 19

10 The required amount of chambers is calculated as follows: S = Total storage required (m³) N = No. of chambers required C = Storage capacity / chamber including. foundation & backfill stone (table 5. 2.) N = S C (e.g = 300m³ 2.3m³) = 131 Chambers Foundation Storage Capacity (m³) Stone* (mm) Per Chamber including foundation & backfill stone* Table 5.2 Chamber Storage Capacity * Figurers shown are for 35-50mm clean washed crushed stone with an assumed void ratio of 40%. A Microsoft excel calculator is available on request for help in sizing the system. It is a user friendly calculator that will give all the relevant information needed in the design of the system. 5.3 Installation The excavation is carried out as per design specification. The site engineer will inspect the excavation and determine the required depth of foundation stone depending on the CBR value of the soil. The excavation is lined in a layer of nonwoven geotextile with lapped joints of 600mm. The foundation stone is then installed and compacted as outlined in section 7. The chambers are then placed side by side in rows across the width of the excavation with a minimum distance of 150mm between adjacent rows. The backfill stone is then installed to a minimum depth of 150mm over the top of the chambers as shown in fig 5.3. The backfill is compacted as outlined in section 7 and is dependent upon the finished use of the area above the tank. A separator / filter layer of non-woven geotextile is then placed over the stone. The depth, type of fill and compaction level above the geotextile to finished ground level is dependent on the finished use of the area above the tank. See section 7 for more details. Fig.5.2 Infiltration Cross Section (installation shown under green area) 8of 19

11 6.0 Attenuation 6.1 Hydraulic Operation During a rainstorm event all stormwater is piped into the catchpit manhole where heavy solids and floatables are trapped. It then flows through the inspection manhole into the silt collection row of HydroChambers which is wrapped in a layer of woven high flow filter geotextile. At low flow rates the water runs straight through the system to the outlet manhole, through the flow control device and on to the storm drain or watercourse. Once the flow rates i.e. rainstorm increases the water fills the tank vertically from the base through the foundation stone while keeping all light silt in the silt collection row. Heavy silt and floatables will be trapped in the catchpit manhole. Once the rainstorm subsides the water drains the system through the Hydro- Valve vortex flow control device. In an impermeable system the excavation is lined with a membrane or liner (GCL) which prevents the water infiltrating the ground and forces all water to exit through the flow control device. Alternatively the system can be left permeable by using a geotextile separator/filter instead of an impermeable liner, this discharges some water into the ground and some to the watercourse or storm drain. This is the recommended system where possible as it discharges firstly to the ground and secondly to the watercourse. Fig.6.1 Attenuation Layout (Sealed System Shown under green area) 9of 19

12 6.2 Attenuation Design A detailed site audit is required to determine if the tank should be sealed or permeable and should be carried out by the consultant engineer. The audit should include analysis of the following parameters: site topography, winter water table level, soil type, soil infiltration rate and local authority regulations. If a sealed system is required the sizing calculation should be carried out using the modified rational method for developed run-off calculations and the institute of hydrology report no.124 for green field runoff or similar approved. For a permeable system the same method should be used and can be combined with the BRE Digest 365 to find the infiltration rate of the ground which can also be taken into account. The required amount of chambers is calculated as follows: S = Total storage required (m³) N = No. of chambers required C = Storage capacity / chamber including. foundation & backfill stone (table 5. 2.) N = S C (e.g = 300m³ 2.3m³) = 131 Chambers Foundation Storage Capacity (m³) Stone* (mm) Per Chamber including foundation & backfill stone* A Microsoft excel calculator is available on request for help in sizing the system. It is a user friendly calculator that will give all the relevant information needed in the design of the system. 6.3 Installation The excavation is carried out as per design specification. The site engineer will inspect the excavation and determine the required depth of foundation stone depending on the CBR value of the soil. The excavation is lined in a layer of impermeable Geosynthetic clay liner, alternatively the excavation can be lined in a non-woven geotextile which allows the water infiltrate the ground as well as discharging to the local watercourse. The stone drain pipe is placed on top of the lined excavation. The foundation stone is then installed to the required depth and compacted. The chambers are then placed side by side in rows across the width of the excavation with a minimum distance of 150mm between adjacent rows. The backfill stone is then installed to a minimum depth of 150mm over the top of the chambers as shown in fig 6.2. The backfill is compacted as outlined in section 7 and is dependent upon the finished use of the area above the tank. A layer of geotextile is placed over the backfill stone. Suitable material is used to backfill to ground level. See the HydroChamber Installation manual for more details on. Table 5.2 Chamber Storage Capacity * Figurers shown are for 35-50mm clean washed crushed stone with an assumed void ratio of 40%. 10 of 19

13 Fig.6.2 Attenuation Layout (impermeable system shown under trafficked area) 7.0 Foundation Design The foundation depth is dependent upon the structural stability of the soil beneath the foundation stone and is the responsibility of the consultant engineer. The subgrade strength should be established by means of a plate bearing test or similar approved to establish the CBR value of the soil as outlined in BS 1377:Part 4:Section 7. The moisture content and density should mimic that in the subgrade when the stormwater management system is in operation. See tables and notes below. The porosity in the foundation and backfill stone is used in the Hydraulic operation of the system. Important Note: Depending on outlet invert levels the liner used on impermeable systems can be placed in the middle of the foundation stone. e.g. 600mm foundation with impermeable liner installed 300mm deep in the foundation stone. See section 8.3 for more details. HydroChamber Foundation Requirements for Soil Loads (Green Areas non trafficked) Soil Type Condition Assumed Foundation Depth CBR <1.5m Cover 1.6m - 2.0m Cover 2.1m - 2.4m Cover <2% seek advise from a Geotechnical Engineer Sandy Clay / Boulder Clay "firm 1 " 2% 0.3m 0.5m 0.6m Sandy Clay / Boulder Clay "stiff 2 " 3% 0.3m 0.3m 0.3m Sand / Gravel "compact 3 " 15% 0.15m 0.15m 0.15m Table. 7.1 Foundation Depth Earth Load HydroChamber Foundation Requirements for Traffic Loads (Car Park Traffic) Soil Type Condition CBR Foundation Depth Value <1.5m Cover 1.6m - 2.0m Cover 2.1m - 2.4m Cover <2% seek advise from a Geotechnical Engineer Sandy Clay / Boulder Clay "firm 1 " 2% 0.3m 0.6m 0.9m Sandy Clay / Boulder Clay "stiff 2 " 3% 0.3m 0.3m 0.6m Sand / Gravel "compact 3 " 15% 0.15m 0.3m 0.3m Table. 7.2 Foundation Depth Traffic Loads 11 of 19

14 Notes: 1. Condition assessed following Building Regulations 1997, Technical guidance Document A, Structure firm sandy clay or boulder clay soil can be moulded by substantial pressure with the fingers and can be excavated with a spade, or see BS5930:1999. Soil stratum to be a minimum of 600mm thick beneath underside of granular fill. 2. Condition assessed following Building Regulations 1997, Technical Guidance Document A, Structure stiff sandy clay or boulder clay soil cannot be moulded with the fingers and requires a pick or pneumatic or other mechanically operated spade for its removal, or see BS5930:1999. Soil stratum to be minimum 600mm thick beneath underside of granular fill. 3. Condition assessed following Building Regulations 1997, Technical Guidance Document A, Structure compact' granular soils require pick for excavation; a wooden peg 50mm square hard to drive beyond 150mm, or see BS5930:1999. All sands and gravels should be proofrolled as described in clause of National Roads Authority Specification for Roadworks (NRA SRW) Series 600 Earthworks. Soil stratum to be minimum 600mm thick beneath underside of granular fill. 8.0 Inverts Levels and Falls Invert levels depend on the type system being installed and cover levels depend on the application of the finished area. 8.1 Infiltration System The inlet / catchpit manhole is to be a minimum of 1.2m in diameter and have a sump of 1.2 meters to catch all heavy silt and floatables entering the system (see fig. 5.1). A second inspection manhole is to be installed just before entry to the tank. A third manhole is then installed on the opposite side for the tank for inspection and maintenance purposes. This can also act as a second inlet manhole provided a catchpit manhole is installed upstream. The outlet pipe from the inlet / Inspection manhole enters the tank at the top of the foundation stone i.e. at the base of the chambers. 8.2 Permeable Attenuation Systems A permeable attenuation system has a catchpit and inspection manhole as detailed above and an outlet manhole installed on the opposite end of the system to the inlet manhole. It is to have a sump of 1m (min. 500mm) to accommodate the Hydro-Valve flow control device and also act as a catchpit. The inlet and outlet pipes of the attenuation system enter the tank at the top of the foundation stone i.e. the base of the chambers. It is recommended a slight fall be put across the tank (e.g. 1:150) but this is not a requirement. 8.3 Impermeable Attenuation Systems (Sealed system) Inlet and outlet manholes will be as detailed in section 8.1 and 8.2. A fall across the tank is necessary to drain the system, recommended 1:150. Important Note: Outlet invert level will be lower than the inlet invert level by the depth of the foundation stone plus the fall in the tank. (see figure 6.1). This is a requirement of the system to drain the foundation stone. There will be a difference in level between the inlet invert and outlet invert of 150mm-600mm depending on the depth of foundation stone and fall. (see section 7 and figure 6.1) 12 of 19

15 9.0 Cover Depths and Levels When used in a green area the system (stone & chambers) is backfilled with as dug material to a minimum cover level of 450mm above the crown of the chambers in accordance with table 9.0 & 9.1 For lightly trafficked areas the chambers are backfilled to a minimum cover level of 600mm above the crown of the chamber in accordance with tables 9.0 & 9.12 See installation manual for loading during construction. 9.1 Backfill Tables The backfill materials and compaction levels are dependent upon the use of the finished area above the system and can be seen in the tables below. For lightly trafficked areas with occasional HGV traffic the chambers are backfilled to a minimum cover level of 750mm above the crown of the chamber in accordance with tables 9.0 and 9.12 Application Traffic Loadings and Cover Depths Min. Max. Cover (mm) Cover (mm) Landscaped Area - (No Traffic) Light Traffic - (Car Park)* Class 3/3 Din Light Traffic with Ocassional HGV Traffic* Class 3/3 with Ocassional Class 16/16 Din * All traffic loadings assume a finished surface Table. 9.0 Cover Depths Backfill Details Under Green Areas (non - trafficked) Layer Material Compaction Compaction Equipment Foundation layer 35-50mm Clean Washed Crushed Stone Compacted to table 6/4 MCDHV Vol.1 Vibrating Roller max gross weight 3000kg Backfill Layer mm Clean Washed Crushed Stone No Compaction Required n/a Backfill Layer 2 As dug material No Compaction Required n/a Table 9.1 Backfill Details under green areas Backfill Details Under Trafficked Areas Layer Material Compaction Compaction Equipment Foundation layer 35-50mm Clean Washed Crushed Stone Compacted to table 6/4 MCDHV Vol.1 Vibrating Roller max gross weight 3000kg Backfill Layer mm Clean Washed Crushed Stone No Compaction Required n/a Backfill Layer 2 Sub Base Type 1 Capping Compacted to table 8/4 in MCDHW Vol.1 Vibrating Roller max gross weight 3000kg 150mm Clause 804 before road surface After a cover level of 500mm is reached Maximum dynamic force of 10,000kgs Table 9.12 Backfill Details trafficked areas Table 9.13 Foundation & Backfill Layers 13 of 19

16 10.0 Alternative Inlet / Outlet Arrangements (Pipe work) The HydroChamber system is extremely versatile and can be adopted in many ways depending on site requirements The designer may wish to use an alternative inlet / outlet arrangement depending on pipe work constraints. Larger systems (where the inlet pipe is greater than 600mm) may require more than one inlet. Contact LSW technical team for more details. Figure 8.0 shows an inline system with the silt collection row offset from the centre. The silt collection row can be placed on any row of chambers provided it is at least two rows from the edge of the excavation (as shown below). Figure 8.1 shows an offset offline system, in this arrangement the inlet manhole is also the outlet / control manhole. A blind inspection / maintenance manhole is also installed on the opposite end of the silt collection row Fig Offset Inline System Fig Offset Offline System 14 of 19

17 11.0 Geotextiles and Liners This section outlines the recommended types of geotextile and liners for use with the HydroChamber system Separator / Filter Geotextile A staple fibre needle punched and thermally bonded non-woven Geotextile, designed to offer optimum performance per unit weight. Their resulting mechanical robustness and excellent hydraulic properties make them the ideal choice for separation and filtration of dissimilar sub-grade materials. It is used in an infiltration / soak-away system to prevents the soil penetrating through the foundation and backfill stone. See table 11.1 for full specification Protector Geotextile The protector geotextile is a heavier and stronger grade of non-woven needle punched and thermally bonded geotextile similar to the separator / filter grade above. It is used on either side of a PVC Geomembrane to protect from the foundation and backfill stone in some sealed attenuation systems. See table 11.2 for full specification High-Flow Filter Geotextile High flow woven geotextiles are unique in that they are woven from polypropylene monofilament tapes & yarns. Their resulting structure forms a very fine filter mesh of uniform opening size. Unlike many other geotextiles this opening size is consistent over the entire length and width of each and every roll. They are widely used in construction and know as anti-clogging geotextiles. This is used under and over the silt collection row to prevent the silt entering the stone and surrounding chambers. This row of chambers can then be flushed from either end if maintenance is required. See table 11.3 for full specification PVC Geomembrane PVC (Polyvinyl Chloride) Geomembrane is a thermoplastic material comprised of PVC resin, plasticizers, stabilization and oxidation agents which are compounded into a flexible Geomembrane sheet designed specifically for the rigorous demands of environmental containment. A pre-welded sheet of PVC can be used between two layers of the protector geotextile to create a sealed system. See table 11.4 for full specification Geo-Composite Clay Liner GCLs are liners consisting of sodium bentonite clay encased between two layers of non-woven geotextile. The bentonite clay liner provides the seal with the geotextile layers protecting the liner against puncture. GCLs provide excellent sealing properties and unique self sealing attributes, reducing risk of failure due to adverse field and operating conditions. This is another lining option for a sealed system which is an easier and quicker way to line the excavation than the PVC membrane as both the protective geotextile and sealing membrane are bonded together to form one single sheet. See table 11.5 for full specification. 15 of 19

18 Non-Woven Protector Geotextile test method value tolerance Mechanical properties Tensile strength MD Tensile strength CD EN ISO kn/m -2,6 kn/m -2,85 kn/m Elongation MD Elongation CD EN ISO % 55 % +/-11,50 % +/-12,70 % Static puncture resistance CBR EN ISO kn -0,72 kn Dynamic perforation resistance cone drop EN mm mm Protection efficiency WI N -66 N Hydraulic properties Water flow normal to the plane EN ISO l/m².s -31,5 l/m².s Water flow capacity in the plane EN ISO x10-6 m²/s -10% log q Characteristic opening size EN ISO µm +/-33,00 µm Physical properties Thickness under 2 kpa EN 964/ mm +/- 0.51mm Weight EN g/m² +/- 30 g/m² Composition 100 % polypropylene non-woven geotextile Table 11.1 Protector Geotextile Specification Non-Woven Separator / Filter Geotextile test method value tolerance Mechanical properties Tensile strength MD Tensile strength CD EN ISO kn/m -1,6 kn/m -1,6 kn/m Elongation MD Elongation CD EN ISO % 50 % +/-11,50 % +/-11,50 % Static puncture resistance CBR EN ISO kn -0,00 kn Dynamic perforation resistance cone drop EN mm + 5 mm Protection efficiency WI N N Hydraulic properties Water flow normal to the plane EN ISO l/m².s -31,5 l/m².s Water flow capacity in the plane EN ISO x10-7 m²/s -10% log q Characteristic opening size EN ISO µm +/-33,00 µm Physical properties Thickness under 2 kpa EN 964/1 1,3 mm +/- 0.26mm Weight EN g/m² +/ g/m² Composition 100 % polypropylene non-woven geotextile Table 11.2 Separator /Filter Geotextile Specification Woven High-Flow Anti-Clog Filter Geotextile test method value tolerance Mechanical properties Tensile strength MD EN ISO kn/m -5,33 kn/m Tensile strength CD EN ISO kn/m -5,98 kn/m Elongation MD Elongation CD EN ISO % 20 % +/-9,2 % +/-4,6 % Static puncture resistance CBR EN ISO ,8 kn -1,16 kn Dynamic perforation resistance cone drop EN mm + 2 mm Hydraulic properties Water permeability normal to the plane EN ISO l/m².s -21 l/m².s Water flow capacity in the plane EN ISO x10-7 m²/s -10% log q Characteristic opening size EN ISO µm +/-52.5 µm Characteristic opening size Physical properties Thickness under 2 kpa EN 964/1 0.7mm +/- 0.14mm Weight EN g/m² +/ g/m² Composition Polypropylene / Polypropylene Woven Geotextile Table 11.3 High Flow Filter Geotextile Specification PVC Membrane test method value Properties Material polyvinylchloride Thickness 0.5mm Colour Black Weight 615g/m² Density DIN gr/cm³ Tensile Strength DIN L, 15D N/mm² Elongation at Break DIN L, 250D% Tearing resistance DIN L, 80D N/mm² Hardness DIN shore A Cold Resistance DIN C Table 11.4 PVC Membrane Specification 16 of 19

19 Geosynthetic Clay Liner (GCL) Test Method Test Frequency Required Values Mechanical properties GCL Index Flux ASTM D5887 Weekly 2 X 10 e-9(m³/m²).s e-1 GCL Permeability ASTM D5084 Weekly 1 X 10 e-11 m.s e-1 ph² BS 1377 Part 2 Weekly 9.8max Bentonite Fluid Loss ASTM D5891 5,000m² 18 ml max. Bentonite Mass / Area³ ASTM D5261 5,000m² 4.8kg.m e-2 GCL Grab Strength ASTM D4632 5,000m² 400N GCL Grab Elongation ASTM D4632 5,000m² 20% typical GCL Peel Strength ASTM D4632 5,000m² 65N Bentonite Swell Index ASTM D5890 5,000m² 24mL/2g min Venting Table11.5 Geosynthetic Clay Liner Specification Venting the system is very important as it allows the air in the system to exit while the chambers and stone are filling with water and also allows air enter the system as it is emptying. A 100mm perforated pipe is used to vent the chambers and stone as shown in the layout below in fig 9.0. A minimum of 12m of vent pipe is run into the inlet manhole in two places as shown below 12.1 Manhole Covers Fig Venting Layout Both the stone and chambers are vented through the inlet manhole. The inlet manhole is to be fitted with a special manhole grate for venting the system. The grate is standard size manhole cover but has open slots to allow for air flow. (see figure 12.1) Fig Manhoel grate 17 of 19

20 13.0 Inspection / Maintenance 13.1 General HydroChamber Storm Water Management Systems are designed to require minimal maintenance, however on certain sites silt and grit can cause problems over a long period of time. The HydroChamber silt collection system will trap all the heavy silt / grit in the catchpit and inspection manholes. The light silt will flow into the silt collection row where it is trapped by the high flow filter geotextile. The inspection / inlet and outlet manholes are connected to the chambers through or Ø600mm pipe for access during inspection and maintenance. entering the system due to construction process. Note: It is not unusual for a large amount of solids to enter the system during construction. When construction is finished and before the site is being handed over. After the first year Bi-annually thereafter of at intervals deemed suitable depending on the rate of silt build up Inspection Inspection is carried out on the silt collection row through the inspection port and / or the Ø600mm inlet / outlet pipes. There are a number ways in which inspection can be carried out: 1. Lower a silt detection probe into the silt collection row and record the depth of silt. 2. Insert a measurement stick with adequate increments to check the depth of the silt. 3. Lower a camera (with light) into the inlet or outlet manhole. 4. Empty the inspection / inlet and or outlet manhole, enter the manhole in accordance with health and safety legislation and visually inspect the silt collection row Inspection Intervals Inspection should be carried out on the system as follows: Periodic inspection during construction depending on the amount of sand, stones, silt etc. Fig Inspection Port 13.3 Maintenance Maintenance is to be carried out once the sump in the catchpit manhole is 75% full of settable solids Maintenance Procedure Empty the catchpit, inspection / inlet and outlet manholes with a vacuum tanker. Flush out the silt collection row of chambers. Repeat until the silt collection row and adjoining manholes are free of silt and grit. 18 of 19

21 14.0 COSHH and Handling Information 14.1 Composition Hazardous ingredients - None Types of Material - medium / high density polyethylene, bentonite, polypropylene geotextile Hazards Identification Nature of Hazard - There are no health risks from the products during normal use First Aid Measurers Eye Contact Plastic Materials may cause physical irritation in the eyes. Wash out with large amounts of water. If irritation persists seek medical advice. Skin Contact Not applicable Inhalation Not applicable 14.4 Fire Fighting Measurers Extinguishing Media On small fires use any hand held extinguisher type. On large fires use water. Fire Hazards Melting Plastic may flow and spread in a large fire. Products or fire will be black thick toxic smoke. Material Characteristics Polyethylene products will burn in the presence of a flame between C. Protective Equipment Wear self contained breathing apparatus and protective clothing Handling and Storage There are no hazards associated with the finished product, however when cutting it is recommended that the correct tools are used e.g. Handsaw or Alligator Saw. During cutting avoid inhaling dust. Pallets of HydroChambers must be stored on level ground and must not be subject to strong winds. Pallets weigh approximately 750kgs, all equipment used to unload and move the pallets must be capable of lifting the weight safely. Prolonged (over one year) storage in direct sunlight should be avoided. The HydroChambers should not be stored near any fuel storage areas or any other solvents. HydroChambers should be stored in an area where they will not get damaged due to construction plant or vehicles Personal Protection Respiratory Protection Not required under normal conditions, when cutting use a disposable half mask to the standard FFP2S. Hand Protection Wear impervious strong gloves. Eye Protection Wear safety glasses when cutting. Skin Protection Wear Overalls 14.7 Site Hazards Working below ground HydroChambers are installed underground and all necessary safety regulations must be adhered to when excavating the trench, work below ground and backfilling the trench Environmental information Stability These products are stable at temperatures up to normal operating conditions. Biodegradability - Plastic products are not readily biodegradable but are not detrimental to terrestrial wildlife. Aquatic Toxicity Not toxic to marine life 14.9 Other Information As the handling, storage, use and disposal are beyond our control, LSW disclaim all liability for loss, damage or other expense during handling and storage. 19 of 19