Tel: 353 1 4500694

Fax: 353 1 4264340

www.kavanaghburke.ie Ulick Burke & Associates Limited. Registered in Ireland No: 233579. V.A.T. Registration No: IE 82335791

Registered Address: Unit G3, Calmount Park, Ballymount, Dublin 12. Directors: U.Burke, R.Burke, P.Kavanagh

Calmount Park, Ballymount, Dublin 12.

Drainage Design Report for Proposed Residential Development at Davitt Road (Former Dulux Site), Drimnagh, Dublin 12

Job No: D1546 Client: DURKAN DAVITT ROAD LTD Date: December 2018. Local Authority: Dublin City Council Revision: PL2 14.12.2018.

Contents:

Introduction

Surface Water Network Design

Catchment 1

Surface Water Attenuation Design

Catchment 1

Surface Water Network Design

Catchment 2

Surface Water Attenuation Design

Catchment 2

Appendix to Surface Water Design

Rainfall table

Specification/Product Information for:

Silt Trap

Flow Control Devices

Green Roofs Direct: Extensive Sedum Roof Build Up Specification

Discharge Units Calculation

Foul Sewer Network Design

Appendix to Foul Sewer Design

Specification/Product Information for:

Petrol Interceptor

INTRODUCTION

This Drainage Design Report accompanies Drainage & Watermain Design Drawings as detailed in the list of submitted drawings contained further within this document.

The proposed development located on lands at the Former Dulux Factory Site at Davitt Road, Drimnagh, Dublin 12 will consist of 265 No. apartment units, a retail/café unit, a resident’s gym, car parking, internal semi-public amenity space, public and private open spaces and all communal facilities in 4 No. 3 to 7 storey blocks. The area of the proposed development is approximately 8266m2 (0.8226ha).

Our engineering design package forms part of an overall planning submission by Brock McClure Planning & Development Consultants for Applicant Durkan (Davitt Road) Ltd.

The drainage and watermain infrastructure approach is described below with drainage

calculations provided in the following pages.

Existing & Proposed Surface Water Drainage

The existing Local Authority drainage records (shown on drawings ref. D1546 - D1 & D1546 - D1-1) indicates 3 No. surface water runs along the proposed development boundary. The closest to the subject site are the existing 450mm pipe on Davitt Road and a 375mm concrete pipe on Galtymore Road. It is proposed to connect the restricted discharge from SW network to the 450mm existing pipe on Davitt Road, as directed by Dublin City Council.

The surface water runoff generated from the proposed development is divided into 2 No. catchments within the overall site. This approach has been adopted due to the surface water outfall location level and to allow a crown connection to the existing 450mm pipe. These 2 No. surface water catchments are noted on the accompanying Drainage Layout drawings ref. D1546-D1 & D1546-D1-1. The runoff from the impermeable areas will be collected in a) slung drainage runs suspended from the underside of the ground floor slab and b) on ground floor level within the external courtyard area and will flow to 2 No. proposed reinforced concrete surface water attenuation tanks #1 & #2 (as indicated on drg. ref. D1546 - D1 & D1546-D1-1). Attenuation tank #1 is proposed to be constructed at a rear landscape area to the South of the Block A & B, while attenuation tank #2 is proposed to be constructed in the courtyard between Block B & D.

These systems are designed to attenuate 1 in 30 year storm event of any duration therefore

no flooding will occur on site for any duration events up to 30 year return period as per

“Greater Dublin Strategic Drainage Study” (GDSDS) requirements. In addition to the

attenuation volume, temporary flood storage is provided (as part of the attenuation system)

for 100year return events up to 6 hours duration as per GDSDS requirements. Since the

temporary flood storage forms part of the overall attenuation tank, maximum allowable

discharge was limited to Q2 calculated flow (see calculations in the succeeding chapters) not

exceeding greenfield runoff rate – QBAR (as per criterion 4.3 “River Flood Protection” chapter

6.3.4 of GDSDS). All flows and runoffs for surface water network design and sizing of

attenuation tanks were calculated including a 10% climate change factor for all rainfall

intensities as per chapter 6.3.2.4 of GDSDS table 6.2 “Climate Change Factors”.

Due to a limited space on site and the invert level of the outfall connection to the existing Local Authority surface water pipe at Davitt Road, any accessible chambers/arch type cells could not be used therefore infiltration cannot be provided through the base of the proposed reinforced concrete attenuation tanks i.e. no interception storage is provided within the RC tanks. However it is proposed to provide interception storage for 5mm and smaller rainfall events in the green roofs of the proposed development. Proposed green roof area for catchment No. 1 is 2050m2 and for catchment No.2 2080 m2. The Max Water Capacity of the green roof substrate for catchment No.1 roof is almost 2.5 times greater & 3.6 times greater for catchment No.2 than required (please refer to the interception storage calculation shown at surface water calculation section) of this Report. Interception storage provided will limit the water runoff from consecutive rainfall events since water will primarily evaporate and to some extent be used by the green roof plants.

Only uncontaminated water runoff from the site (runoff from the green roofs and the pedestrian routes on site) will be attenuated in the proposed tanks therefore eliminating the necessity for a petrol interceptor. However silt traps will be provided upstream of the attenuation facilities to intercept possible silt/debris that may be contained in the runoff water. These water quality control items are the first defence against possible pollutants prior to the runoff water entering the system as described above.

The restricted flow from the site is designed to control the flow to Q2 limits as per current Greater Dublin Strategic Drainage Study (GDSDS) SuDS design and will be installed on the outfall of the SW MH 04 limiting site runoff before entering the existing public surface water pipe on Davitt Road.

Surface water drainage calculations for both catchments are attached demonstrating the

design flows and network capacities of the proposal.

Existing & Proposed Foul Sewer

The existing Local Authority drainage records (refer to the drawing ref.D1546 - D2 & D1546 - D2-1) shows 2 no. foul sewer pipes along the site’s southern and northern boundary: a 300mm foul sewer is located at the South of the Site on Galtymore Road and a 1500mm combined sewer is located at the North of the Site on Davitt Road.

The proposed foul sewer is designed to accommodate the proposed development of 265 No. apartment units, a retail/café unit and a resident’s gym. It is proposed to discharge all effluent by gravity and to connect at the crown of the existing 1500mm public combined sewer on Davitt Road, as directed by Dublin City Council.

The foul network for the proposed development is modelled in Micro Drainage design software based on the fixture unit method that takes into account the probability of simultaneous discharge from different fixtures and translates it to the design flow as set out in BS8301 “Code of Practice for Building Drainage”. Calculation of discharge units per Blocks is enclosed within this Drainage Report.

The basement drainage will be pumped via rising main to a proposed discharge manhole at the ground floor level. From this location it will outfall by gravity along with the slung foul network flows to the proposed connection location at public sewer, refer to the accompanying drawings ref. D1546 - D2 - Basement Plan-Proposed Drainage-Foul Sewer & D1546 - D2-1 - Ground Floor Plan-Proposed drainage-Foul Sewer. The basement carpark drainage will pass through a Class I Petrol Interceptor prior to being pumped to the ground floor level.

As per requirements of the Irish Water Code of Practice, minimum velocities of 0.75 m/s are

met for the proposed gradients and contributing unit numbers. The proposed foul sewer

including manholes and service connections will be constructed in compliance with design

standards set out by Irish Water in the Irish Water Code of Practice for Wastewater

Infrastructure and Wastewater Infrastructure Standard Details.

Existing & Proposed Watermain

The current Local Authority records (refer to the drawing ref.D1546 - D3 & D1546 - D3-1 enclosed) shows an existing 1000mm dia. watermain on the footpath at Davitt Road next to the site’s boundary. 2 No. 450mm dia. water mains located at the boundary between Davitt Road and Red Luas Track while a 4” (100mm) diameter watermain is located at the site’s Southern boundary at Galtymore Road.

Water Supply to development is proposed by connection to the existing Local Authority 450mm watermain at Davitt Road. A 150mm diameter water mains will be provided throughout the proposed site with water meters and sluice valves as shown on the Watermain Layout drawing Ref. D1546 - D3 & D1546 - D3-1. Part of the proposed looped watermain will be laid in the ground and part will be within the basement as a slung watermain to the underside of the ground floor slab.

Guidelines set out in the Irish Water Publications IW-CDS_5020-1 & IW-CDS-5030-1 have been consulted and adopted regarding the proposed drainage & watermain networks. The following Kavanagh Burke documents are attached which form part of an overall planning application submitted by Brock McClure Planning & Development Consultants;

Existing Site Plan Drawing Ref: D1546 - D0

Proposed Site Plan Drawing Ref: D1546 - D0-1

Basement Plan: Proposed Drainage - Surface Water Drawing Ref: D1546 - D1

Ground Floor Plan: Proposed Drainage - Surface Water Drawing Ref: D1546 - D1-1

Basement Plan: Proposed Drainage - Foul Sewer Drawing Ref: D1546 - D2

Ground Floor Plan: Proposed Drainage - Foul Sewer Drawing Ref: D1546 - D2-1

Basement Plan: Watermain Layout Drawing Ref: D1546 - D3

Ground Floor Plan: Watermain Layout Drawing Ref: D1546 - D3-1

Sections Drawing Ref: D1546 - D4

Watermain Details Drawing Ref: D1546 - D5

Drainage Design Report

Surface Water Network Design

Catchment 1

ED

Text Box

SURFACE WATER NETWORK #1 SCHEME

Burke Jenkins Page 1

Consulting Engineers St Edmunds Dev

21 Cookstown Ind Est Palmerstown

Tallaght Dublin 24 Dublin 20

Date 10-12-14 Designed By DOS

File D1546 - Storm - catchment1 A&... Checked By

CADS Storm W.7.3 (c)1982-2000 Micro Drainage

STORM SEWER DESIGN by the Modified Rational Method

Global Variables

Location - Scotland & Ireland

Return Period (years) 2 Volumetric Runoff Coeff. 0.75M5-60 (mm) 18 Infiltration % 0Ratio R 0.28 Minimum Backdrop Height (m) 0.000Maximum Rainfall (mm/hr) 50 Depth from Soffit to G.L. (m) 1.200Foul Sewage (l/s/ha) 0.00 Min Vel. (m/s - Auto Design Only) 0.80O'flow Setting (*Foul only) 0 Min Slope (1:X - Optimisation) 500

Designed with Level Soffits

Network Design Table

PN

Length(m)

Fall(m)

Slope(1:X)

Area(ha)

T.E.(mins)

DWF(l/s)

k(mm)

HYDSECT

DIA(mm)

1.000 46.00 0.225 204.4 0.115 5.00 0 0.600 o 2251.001 63.00 0.285 221.1 0.100 0.00 0 0.600 o 2251.002 27.00 0.120 225.0 0.080 0.00 0 0.600 o 3001.003 10.00 0.050 200.0 0.000 0.00 0 0.600 o 3001.004 13.50 0.070 192.9 0.000 0.00 0 0.600 o 300

2.000 17.00 0.150 113.3 0.070 5.00 0 0.600 o 2252.001 11.00 0.080 137.5 0.050 0.00 0 0.600 o 2252.002 11.00 0.080 137.5 0.030 0.00 0 0.600 o 225

1.005 5.00 0.200 25.0 0.000 0.00 0 0.600 o 300

Network Results Table

PN

Rain(mm/hr)

T.C.(mins)

US/IL(m)

E.Area(ha)

E.DWF(l/s)

Foul(l/s)

Infil.(l/s)

Vel(m/s)

CAP(l/s)

Flow(l/s)

1.000 50.0 5.8 28.500 0.115 0 0 0 0.91 36 161.001 48.2 7.0 28.275 0.215 0 0 0 0.88 35 281.002 47.0 7.5 27.915 0.295 0 0 0 1.04 74 381.003 46.6 7.6 27.795 0.295 0 0 0 1.11 78 381.004 46.1 7.8 27.745 0.295 0 0 0 1.13 80 38

2.000 50.0 5.2 28.500 0.070 0 0 0 1.23 49 92.001 50.0 5.4 28.350 0.120 0 0 0 1.11 44 162.002 50.0 5.6 28.270 0.150 0 0 0 1.11 44 20

1.005 46.0 7.8 27.000 0.445 0 0 0 3.16 223 55

Surface Water Attenuation Design

Catchment 1

Surface Water Attenuation Calculations – CATCHMENT 1 /Block A & C/:

1) Interception Storage

Calculate runoff from 5mm of rainfall on developed area. For this calculation only

hardstanding areas are assumed to provide 80% runoff, and non-hardstanding areas are

assumed to provide 0% runoff.

The equivalent volume of Interception Storage should be provided on site as no discharge

from site should occur for this depth of rainfall. The Interception Storage on this subject site

will be provided through the green roofs.

Site Area of development: 8266m2 (0.8266 ha)

Size of Catchment 1: 4075 m2

Green roof: 2050 m2

Permeable paving: 395 m2

Impermeable Areas: 3680 m2

Design Impermeable Areas: 3680 m2 x 0.8 =

2944 m2

Total volume for 5mm rainfall: 5mm x 2944 m2 =

14.7 m3

Therefore a minimum Interception Storage volume of 14.7m3 should be provided. This will

prevent discharge from the portion of the site during rainfall events of up to 5mm rainfall.

Research from around the world indicates that Green Roofs reduce annual run-off from roofs by

at least 50%, and more usually by 60-70% - contributing to urban drainage and flood alleviation

schemes. Moreover, the rate of release following heavy rainfall is slowed, reducing the problems

associated with storm surges. With an increasing need for developments to have limited water

runoff, the UK’s Environment Agency now highlight the use of green roofing in their May 2003

publication “Sustainable Drainage Systems (SUDS) – an introduction.”

Proposed sedum blanket type roof thickness varies form 25 – 45mm and it is installed on 50mm

multi-layer roof substrate composed of mineral bulk mixture with a proportion of mineral and

organic matter. Maximum water capacity of roof substrate layer is ≥35%.

Max Water Capacity for subject roof: 2050m2 x 50mm x 35% = 35.875m3

It is proposed to use the green roof for interception storage for 5mm and smaller rainfall events.

Max water capacity of the substrate is almost 2.5 times greater than required interception

storage which will limit the water runoff from consecutive rainfall events since water from

interception storage will not infiltrate to the subsoil but will be dealt with primarily by

evaporation and to some extent used by the green roof plants.

Rainfall runoff from roofs can contain pollutants for example, from bird droppings and

atmospheric pollution. As well, a standard roof covering such as bitumen will give off a range of

pollutants under heat stress, which then are carried along with the runoff. One of the roles of a

sustainable urban drainage system is to remove some if not all of this pollution. Green roofs can

retain and bind contaminants that fall on their surface either as dust or dissolved in rainwater.

Research by (Johnston et al, 2004) found that 95% of heavy metals are removed from runoff by

green roofs and nitrogen levels can be reduced.

1) Greenfield Runoff Rate – QBAR, (mean annual flood flow):

QBARrural (m3/sec) = 0.00108 x AREA0.89 x SAAR1.17 x SOIL2.17

SAAR (E 312000, N 233000): 719mm

Soil Index: S1 (very low runoff)

S2

S3 (moderate runoff)

S4

S5 (very high runoff)

Soil = 0.1(Soil1) + 0.3(Soil2) + 0.37(Soil3) + 0.47(Soil4) + 0.53(Soil5)

As the site is relatively small in catchment terms the soil class is 100% Soil2

Soil Class: Soil2

Runoff Potential: Low

Soil Value: 0.3

QBAR:

As the site area is less than 50 hectares;

QBAR for 50 hectares is firstly calculated,

QBAR (m3/sec) = 0.00108 x AREA0.89 x SAAR1.17 x SOIL2.17

0.00108 x (0.5)0.89 x (719)1.17 x (0.3)2.17

94.02 l/sec

1.88 l/sec/ha

QBAR for the smaller area (i.e. the subject catchment area):

1.88 l/sec/ha x 0.4075ha

0.77 l/sec

Calculate flood flows for 2y return period:

QBAR = 0.77 l/sec

Q2 = 0.95 x 0.77 l/sec = 0.73 l/sec

(ALLOWABLE DISCHARGE based on peak flood flow for 2 year return or 2 l/sec/ha,

whichever is greater), 2 l/sec/ha x 0.4075 ha = 0.815 l/sec, therefore Q2 value of

Q2 = 2.0 l/sec applies.

The peak flow rate factor of 0.95 above is taken from tabulated values of growth curve

multipliers for the Dublin area.

Minimum achievable hydrobrake flow rate is 2.0 l/sec therefore allowable discharge (Q2) will

be set at 2.0 l/sec.

2a) Attenuation Volume

80% of hardstand areas are assumed to contribute.

Soil SPR Value – 0.3, therefore 30% of non-hardstand areas assumed to contribute.

Equivalent Runoff Area: 80% x 3680 m2 + 30% x 395 m2

2944 m2 + 118.50 m2 =

3062.50 m2

Met Eireann’s Rainfall depths for the 30 year storm event have been used. The table below

identified the 6 hour event as the critical event. The rainfall depth used includes a 10% allowance

for climate change giving a volume of 127.26m3 - (Column G).

A B C D E F G

Duration Runoff Area

Total Rainfall Depth

Revised Depth for

10% Climate Change

Total Surface Water

Total Permitted Discharge

Storage Volume

Required

(m2) (mm) (mm) C x 1.1 (m3) B x D (m3) Q2 x A

(Q2=2.00 l/sec) (m3) E - F

15 min 3062.50 18.00 19.80 60.64 1.80 58.84

30 min 3062.50 22.60 24.86 76.13 3.60 72.53

1 hour 3062.50 28.30 31.13 95.34 7.20 88.14

2 hour 3062.50 35.40 38.94 119.25 14.40 104.85

4 hour 3062.50 44.30 48.73 149.24 28.80 120.44

6 hour 3062.50 50.60 55.66 170.46 43.20 127.26

12 hour 3062.50 63.30 69.63 213.24 86.40 126.84

1 day 3062.50 79.30 87.23 267.14 172.80 94.34

An allowance to account for the simplifying assumption of head - discharge relationship of 1.25

is applied (due to simple calculations assuming the maximum flow rate can be mobilised

immediately for each design return period.

Revised Critical Volume: 127.26 x 1.25 = 159.1 m3

When this storage volume is being used for the 30 year storm event, no surface flooding should

occur.

2) Temporary Flood Storage

In addition to the previous calculations for interception & attenuation storage, the temporary

flood storage must be calculated.

The 6 hour duration, 100 year return period must be checked to assess the temporary flood

storage required for the site.

100 year 6 hour event, rainfall depth: 68.2 mm

Factor up by 10% for climate change: 75.02 mm

Total Volume of Runoff: 75.02 mm x 3062.50 m2 = 229.75 m3

Deduct discharge at Q2 for 5hrs: 2.0 l/sec x 6 hrs = 43.20 m3

Storage volume required; 229.75 - 43.20 = 186.55 m3

Factor up for head relationship factor; 186.55 x 1.25 = 233.1 m3

Deduct Attenuation Storage; 159.1 m3

Temporary Flood Storage required: 233.1 - 159.1 = 74 m3

___________________________

In summary:

Required Attenuation Volume: 159m3 to be provided within the attenuation system on site.

Temporary Flood Storage: 74m3 can also be accommodated within the attenuation system

provided - see system volumes below.

Total volume required: 159m3 + 74m3 = 233m3

Total volume provided: 233m3

Surface Water Network Design

Catchment 2

ED

Text Box

SURFACE WATER NETWORK #2 SCHEME

Burke Jenkins Page 1

Consulting Engineers St Edmunds Dev

21 Cookstown Ind Est Palmerstown

Tallaght Dublin 24 Dublin 20

Date 10-12-14 Designed By DOS

File D1546 - Storm - catchment2 - B... Checked By

CADS Storm W.7.3 (c)1982-2000 Micro Drainage

STORM SEWER DESIGN by the Modified Rational Method

Global Variables

Location - Scotland & Ireland

Return Period (years) 2 Volumetric Runoff Coeff. 0.75M5-60 (mm) 18 Infiltration % 0Ratio R 0.28 Minimum Backdrop Height (m) 0.000Maximum Rainfall (mm/hr) 50 Depth from Soffit to G.L. (m) 1.200Foul Sewage (l/s/ha) 0.00 Min Vel. (m/s - Auto Design Only) 0.80O'flow Setting (*Foul only) 0 Min Slope (1:X - Optimisation) 500

Designed with Level Soffits

Network Design Table

PN

Length(m)

Fall(m)

Slope(1:X)

Area(ha)

T.E.(mins)

DWF(l/s)

k(mm)

HYDSECT

DIA(mm)

1.000 30.00 0.130 230.8 0.030 5.00 0 0.600 o 2251.001 19.00 0.080 237.5 0.030 0.00 0 0.600 o 225

2.000 20.00 0.210 95.2 0.050 5.00 0 0.600 o 225

1.002 4.50 0.020 225.0 0.000 0.00 0 0.600 o 225

3.000 40.00 0.190 210.5 0.060 5.00 0 0.600 o 2253.001 13.50 0.060 225.0 0.040 0.00 0 0.600 o 225

1.003 2.50 0.015 166.7 0.000 0.00 0 0.600 o 225

4.000 38.00 0.170 223.5 0.090 5.00 0 0.600 o 225

1.004 3.00 0.015 200.0 0.000 0.00 0 0.600 o 300

Network Results Table

PN

Rain(mm/hr)

T.C.(mins)

US/IL(m)

E.Area(ha)

E.DWF(l/s)

Foul(l/s)

Infil.(l/s)

Vel(m/s)

CAP(l/s)

Flow(l/s)

1.000 50.0 5.6 26.350 0.030 0 0 0 0.86 34 41.001 50.0 6.0 26.220 0.060 0 0 0 0.84 34 8

2.000 50.0 5.2 26.350 0.050 0 0 0 1.34 53 7

1.002 50.0 6.0 26.140 0.110 0 0 0 0.87 34 15

3.000 50.0 5.7 26.370 0.060 0 0 0 0.90 36 83.001 50.0 6.0 26.180 0.100 0 0 0 0.87 34 14

1.003 50.0 6.1 26.120 0.210 0 0 0 1.01 40 28

4.000 50.0 5.7 26.275 0.090 0 0 0 0.87 35 12

1.004 50.0 6.1 26.030 0.300 0 0 0 1.11 78 41

Surface Water Attenuation Design

Catchment 2

Surface Water Attenuation Calculations – CATCHMENT 2 /Block B & D/:

1) Interception Storage

Calculate runoff from 5mm of rainfall on developed area. For this calculation only

hardstanding areas are assumed to provide 80% runoff, and non-hardstanding areas are

assumed to provide 0% runoff.

The equivalent volume of Interception Storage should be provided on site as no discharge

from site should occur for this depth of rainfall. The Interception Storage on this subject site

will be provided through the green roofs.

Site Area of development: 8266m2 (0.8266 ha)

Size of Catchment 1: 4191 m2

Green roof: 2080 m2

Permeable paving: 1113 m2

Impermeable Areas: 2528 m2

Design Impermeable Areas: 2528 m2 x 0.8 =

2022.40 m2

Total volume for 5mm rainfall: 5mm x 2022.40 m2 =

10.11 m3

Therefore a minimum Interception Storage volume of 10.1m3 should be provided. This will

prevent discharge from the portion of the site during rainfall events of up to 5mm rainfall.

Research from around the world indicates that Green Roofs reduce annual run-off from roofs by

at least 50%, and more usually by 60-70% - contributing to urban drainage and flood alleviation

schemes. Moreover, the rate of release following heavy rainfall is slowed, reducing the problems

associated with storm surges. With an increasing need for developments to have limited water

runoff, the UK’s Environment Agency now highlight the use of green roofing in their May 2003

publication “Sustainable Drainage Systems (SUDS) – an introduction.”

Proposed sedum blanket type roof thickness varies form 25 – 45mm and it is installed on 50mm

multi-layer roof substrate composed of mineral bulk mixture with a proportion of mineral and

organic matter. Maximum water capacity of roof substrate layer is ≥35%.

Max Water Capacity for subject roof: 2080m2 x 50mm x 35% = 36.40 m3

It is proposed to use the green roof for interception storage for 5mm and smaller rainfall events.

Max water capacity of the substrate is 3.6 times greater than required interception storage which

will limit the water runoff from consecutive rainfall events since water from interception storage

will not infiltrate to the subsoil but will be dealt with primarily by evaporation and to some extent

used by the green roof plants.

Rainfall runoff from roofs can contain pollutants for example, from bird droppings and

atmospheric pollution. As well, a standard roof covering such as bitumen will give off a range of

pollutants under heat stress, which then are carried along with the runoff. One of the roles of a

sustainable urban drainage system is to remove some if not all of this pollution. Green roofs can

retain and bind contaminants that fall on their surface either as dust or dissolved in rainwater.

Research by (Johnston et al, 2004) found that 95% of heavy metals are removed from runoff by

green roofs and nitrogen levels can be reduced.

2) Greenfield Runoff Rate – QBAR, (mean annual flood flow):

QBARrural (m3/sec) = 0.00108 x AREA0.89 x SAAR1.17 x SOIL2.17

SAAR (E 312000, N 233000): 719mm

Soil Index: S1 (very low runoff)

S2

S3 (moderate runoff)

S4

S5 (very high runoff)

Soil = 0.1(Soil1) + 0.3(Soil2) + 0.37(Soil3) + 0.47(Soil4) + 0.53(Soil5)

As the site is relatively small in catchment terms the soil class is 100% Soil2

Soil Class: Soil2

Runoff Potential: Low

Soil Value: 0.3

QBAR:

As the site area is less than 50 hectares;

QBAR for 50 hectares is firstly calculated,

QBAR (m3/sec) = 0.00108 x AREA0.89 x SAAR1.17 x SOIL2.17

0.00108 x (0.5)0.89 x (719)1.17 x (0.3)2.17

94.02 l/sec

1.88 l/sec/ha

QBAR for the smaller area (i.e. the subject site area):

1.88 l/sec/ha x 0.4191ha

0.79 l/sec

Calculate flood flows for 2y period:

QBAR = 0.790 l/sec

Q2 = 0.95 x 0.79 l/sec = 0.75 l/sec

(ALLOWABLE DISCHARGE based on peak flood flow for 2 year return or 2 l/sec/ha,

whichever is greater), 2 l/sec/ha x 0.4191 ha = 0.84 l/sec, therefore Q2 value of

Q2 = 2.0 l/sec applies.

The peak flow rate factor of 0.95 above is taken from tabulated values of growth curve

multipliers for the Dublin area.

Minimum achievable hydrobrake flow rate is 2.0 l/sec therefore allowable discharge (Q2) will

be set at 2.0 l/sec.

2a) Attenuation Volume

80% of hardstand areas are assumed to contribute.

Soil SPR Value – 0.3, therefore 30% of non-hardstand areas assumed to contribute.

Equivalent Runoff Area: 80% x 2528 m2 + 30% x 1113 m2 =

2022.40 m2 + 333.90 m2 =

2356.30 m2

Met Eireann’s Rainfall depths for the 30 year storm event have been used. The table below

identified the 6 hour event as the critical event. The rainfall depth used includes a 10% allowance

for climate change giving a volume of 87.95m3 - (Column G).

A B C D E F G

Duration Runoff Area

Total Rainfall Depth

Revised Depth for

10% Climate Change

Total Surface Water

Total Permitted Discharge

Storage Volume

Required

(m2) (mm) (mm) C x 1.1 (m3) B x D (m3) Q2 x A

(Q2=2.00 l/sec) (m3) E - F

15 min 2356.30 18.00 19.80 46.65 1.80 44.85

30 min 2356.30 22.60 24.86 58.58 3.60 54.98

1 hour 2356.30 28.30 31.13 73.35 7.20 66.15

2 hour 2356.30 35.40 38.94 91.75 14.40 77.35

4 hour 2356.30 44.30 48.73 114.82 28.80 86.02

6 hour 2356.30 50.60 55.66 131.15 43.20 87.95

12 hour 2356.30 63.30 69.63 164.07 86.40 77.67

1 day 2356.30 79.30 87.23 205.54 172.80 32.74

An allowance to account for the simplifying assumption of head – discharge relationship of 1.25

is applied (due to simple calculations assuming the maximum flow rate can be mobilised

immediately for each design return period).

Revised Critical Volume: 87.95 x 1.25 = 110 m3

When this storage volume is being used for the 30 year storm event, no surface flooding should

occur.

3) Temporary Flood Storage

In addition to the previous calculations for interception & attenuation storage, the temporary

flood storage must be calculated.

The 6 hour duration, 100 year return period must be checked to assess the temporary flood

storage required for the site.

100 year 6 hour event, rainfall depth: 68.2 mm

Factor up by 10% for climate change: 75.02 mm

Total Volume of Runoff: 75.02 mm x 2356.30 m2 = 176.8 m3

Deduct discharge at Q2 for 5hrs: 2.0 l/sec x 6 hrs = 43.20 m3

Storage volume required; 176.8 - 43.20 = 133.6 m3

Factor up for head relationship factor; 133.6 x 1.25 = 167 m3

Deduct Attenuation Storage; 110 m3

Temporary Flood Storage required: 167 - 110 = 57 m3

___________________________

In summary:

Required Attenuation Volume: 110m3 to be provided within the attenuation system on site.

Temporary Flood Storage: 57m3 can also be accommodated within the attenuation system

provided - see system volumes below.

Total volume required: 110m3 + 57m3 = 167m3

Total volume provided: 167m3

Appendix to Surface Water Design Rainfall table

Specification/Product Information for:

Silt Trap

Flow Control Devices

Green Roofs Direct: Extensive Sedum Roof Build Up

Specification

Met Eireann Return Period Rainfall Depths for sliding Durations Irish Grid: Easting: 312385, Northing: 233010,

Interval | YearsDURATION 6months, 1year, | 2, 3, 4, 5, 10, 20, 30, 50, 75, 100, 150, 200, 250, 500, 5 mins 2.4, 3.5, | 4.1, 5.1, 5.7, 6.2, 7.8, 9.7, 11.0, 12.8, 14.4, 15.7, 17.7, 19.3, 20.6, N/A , 10 mins 3.4, 4.9, | 5.8, 7.0, 7.9, 8.6, 10.9, 13.6, 15.3, 17.9, 20.1, 21.9, 24.7, 26.8, 28.6, N/A , 15 mins 4.0, 5.8, | 6.8, 8.3, 9.3, 10.1, 12.8, 16.0, 18.0, 21.0, 23.7, 25.8, 29.0, 31.6, 33.7, N/A , 30 mins 5.3, 7.5, | 8.8, 10.7, 12.0, 13.0, 16.3, 20.1, 22.6, 26.2, 29.4, 31.9, 35.7, 38.7, 41.3, N/A , 1 hours 7.0, 9.8, | 11.4, 13.7, 15.3, 16.6, 20.6, 25.2, 28.3, 32.6, 36.4, 39.4, 44.0, 47.6, 50.5, N/A , 2 hours 9.2, 12.8, | 14.8, 17.7, 19.7, 21.2, 26.1, 31.7, 35.4, 40.6, 45.2, 48.7, 54.1, 58.4, 61.9, N/A , 3 hours 10.8, 15.0, | 17.2, 20.5, 22.7, 24.5, 30.0, 36.3, 40.4, 46.1, 51.2, 55.1, 61.2, 65.8, 69.6, N/A , 4 hours 12.1, 16.7, | 19.2, 22.8, 25.2, 27.1, 33.1, 39.9, 44.3, 50.5, 56.0, 60.2, 66.7, 71.6, 75.8, N/A , 6 hours 14.3, 19.6, | 22.3, 26.4, 29.2, 31.3, 38.1, 45.6, 50.6, 57.5, 63.5, 68.2, 75.3, 80.8, 85.3, N/A , 9 hours 16.8, 22.8, | 26.0, 30.6, 33.7, 36.1, 43.7, 52.2, 57.7, 65.3, 72.0, 77.2, 85.0, 91.0, 96.0, N/A ,12 hours 18.9, 25.5, | 28.9, 34.0, 37.4, 40.0, 48.3, 57.4, 63.3, 71.6, 78.8, 84.3, 92.7, 99.1, 104.4, N/A ,18 hours 22.3, 29.8, | 33.7, 39.4, 43.2, 46.1, 55.4, 65.7, 72.2, 81.4, 89.3, 95.4, 104.7, 111.8, 117.6, N/A ,24 hours 25.0, 33.3, | 37.5, 43.8, 47.9, 51.1, 61.2, 72.2, 79.3, 89.1, 97.7, 104.2, 114.1, 121.7, 127.9, 149.2, 2 days 30.8, 40.2, | 45.0, 51.9, 56.4, 59.8, 70.8, 82.6, 90.1, 100.4, 109.3, 116.1, 126.3, 134.1, 140.4, 162.1, 3 days 35.5, 45.7, | 50.9, 58.4, 63.3, 66.9, 78.6, 91.0, 99.0, 109.7, 119.0, 126.1, 136.7, 144.7, 151.2, 173.5, 4 days 39.6, 50.6, | 56.1, 64.1, 69.2, 73.1, 85.4, 98.4, 106.7, 117.9, 127.6, 134.9, 145.8, 154.1, 160.8, 183.6, 6 days 46.7, 59.0, | 65.2, 73.9, 79.6, 83.8, 97.1, 111.2, 120.1, 132.1, 142.4, 150.1, 161.7, 170.4, 177.5, 201.4, 8 days 53.0, 66.4, | 73.1, 82.5, 88.6, 93.2, 107.4, 122.4, 131.8, 144.5, 155.3, 163.4, 175.5, 184.6, 192.0, 216.9, 10 days 58.8, 73.2, | 80.3, 90.3, 96.8, 101.6, 116.6, 132.4, 142.3, 155.6, 166.9, 175.4, 188.0, 197.5, 205.1, 230.9, 12 days 64.2, 79.5, | 87.0, 97.6, 104.4, 109.5, 125.2, 141.7, 152.0, 165.9, 177.6, 186.4, 199.5, 209.3, 217.2, 243.8, 16 days 74.1, 91.0, | 99.2, 110.8, 118.2, 123.8, 140.9, 158.7, 169.7, 184.5, 197.1, 206.4, 220.3, 230.7, 239.1, 267.1, 20 days 83.3, 101.6, | 110.5, 123.0, 130.9, 136.9, 155.1, 174.1, 185.8, 201.5, 214.7, 224.6, 239.2, 250.1, 258.9, 288.2, 25 days 94.0, 113.9, | 123.6, 137.0, 145.6, 152.0, 171.5, 191.8, 204.3, 220.9, 234.9, 245.3, 260.8, 272.3, 281.6, 312.3,NOTES:N/A Data not availableThese values are derived from a Depth Duration Frequency (DDF) ModelFor details refer to:’Fitzgerald D. L. (2007), Estimates of Point Rainfall Frequencies, Technical Note No. 61, Met Eireann, Dublin’, Available for download at www.met.ie/climate/dataproducts/Estimation-of-Point-Rainfall-Frequencies_TN61.pdf

TM

Specialists in Wastewater Treatment & Stormwater Management

The CDS Non Blockingscreening technology is aninnovative method ofliquid / solid separationfor Surface Water, CombinedSewer Overflows (CSO)and Foul Sewage Systems.

• SurfSep for Surface Water applications

• OverSep for Combined SewerOverflow applications.

The technology accomplishes highefficiency separation of settleableparticulate matter and capture offloatable material.

A unique feature of the CDS Technologyis it’s compact design. Both the SurfSepand OverSep are available as packagedsystems, which can either be installedinside pre-cast concrete chamber rings,or complete BBA ApprovedPolyethylene Chambers unit.

Applications

• Storm-water Treatment

• Combined Sewer Overflow Treatment

• Parking Area Run-Off Treatment

• Vehicle Service Yard Areas

• Pre-treatment for Wetlands, Ponds and Swales

• Rainwater Harvesting

• Pre-treatment for Oil Separators

• Pre-treatment for media and GroundIn-filtration Systems

Surface Water TreatmentSUDs Protector

TM

2

Surface Water System

Hydraulic Analysis

In storm water applications, an analysis of the catchment in terms of its size,topography and land use will provide information for determining flow to beexpected for various return periods.

The SurfSep is designed for the flow that mobilizes the gross pollutants within thecatchment. Since there are variations in catchment response due to region, land useand topography, it is recommended that the selection of flow to be treated will befor return periods of between 3 months and 1 year.

Balancing the cost to the operator against the benefits tothe environment

Field evaluations to determine pollutant mobilization have found that the vastmajority of pollutants are mobilized in flows that are well below the design capacity’for the conveyance facility - typically known as the ‘first flush’.

Therefore it is typical not to design the SurfSep models to process the conveyancesystem’s maximum flow in order to achieve a very high level of pollutant removal.

The added value benefit to the operator is reduced civil costs withoutcompromising the benefits to the environment.

How it works

Water and pollutants enter the system and are introduced tangentially inside theseparation chamber forming a circular flow motion. Floatables and suspended solidsare diverted to the slow moving centre of the flow. Negatively buoyant solids settleout to an undisturbed sump chamber below, while the water passescountercurrently through theseparation screen. Floatables remain at the water surface and retainedwithin the screen.

Rapidinstallation

Primary features

• Effective: Capturing more than95% of solid pollutants.

• Non-Blocking: Unique designtakes advantage of indirect filtrationand properly proportioned hydraulicforces that virtually makes the unitunblockable.

• Non-Mechanical: The unit hasno moving parts and requires nomechanical devices to support thesolid separation function.

• Low Maintenance Costs:The system has no moving parts andis fabricated of durable materials.

• Compact & Flexible: Designand size flexibility enables the use ofvarious configurations.

• High Flow Effectiveness:The technology remains highlyeffective across a broad spectrum offlow ranges.

• Assured PollutantCapture: All materials capturedare retained during high flowconditions.

• Safe & Easy Pollutant Removal:Extraction methods allow safe and easy removal of pollutants without manual handling.

Hydraulic Design

Every application requires a detailed hydraulic analysis to ensure the final installationwill perform to effect optimum solids separation without blocking the screen.

After the design flow has been determined, the appropriate standard model can beselected. A selection table is provided on page 7.

The Ultimate SUDs Protector

There a four principal areas of proprietary SUDs technology;

• Infiltration • Flow Control • Storage/attenuation • Treatment

SurfSeps, although a common form of treatment are unique.When installed upstreamof any proprietary SUDs technology, the SurfSep protects the receiving SUDs from finesolids and debris that would otherwise accumulate over time rendering the SUDs non-operational, as the worst case.

SurfSeps have been successfully installed in front of;

• Soakaways

• Infiltration Trenches

• Filters

• Wetlands

• Ponds and Water Features

• Detention and Retention Systems

• Oil Separators

• Create storage storage systems

to remove fine solids and debris that would otherwise accumulate over time reducingthe down stream effectiveness of downstream SUDs assets.

Various independent field trials have shown that the SurfSep can remove high levels ofPhosphates, Heavy Metals and PolyAramatic Hydrocarbons (PAH’s) from the flow.

Infiltration

SurfSeps have been successfully installed in front of ground Infiltration systems toremove grit, fine solids and debris which accumulates in and around the SUDs causingvisual degradation in the short term and accumulation of silt and grits leading toreduced volume in the long term.

Studies have also shown that Heavy metals & PAH’s accumulate within the SUDs overtime before being released back to the environment resulting in elevated concentrations.

Detention & RetentionSystems

SurfSeps have been successfully installed infront of collection and attenuation SUDsto remove grit, fine solids and debriswhich accumulates in the SUDs leading topotential blockage of flow regulatorsresulting in increased Occupational Health& Safety risk during the treatment ofblockages and during the periodiccleaning operations.

Applications

• Rainwater Harvesting

• Road run off

• New Developments

• Motorways

• A / B Roads

• Local Roads

• Residential

• Industrial

• Commercial

Purpose

Removal of plastics, oil, grit, fine solids,organic and inorganic debris, from pointsource pollution.

Surface Water Treatment Systems

TM

4

Flow Control Systems

Flow Control Technical Design

The Hydroslide regulator does not affect the flow until the flow is approaching the setdischarge limit, this allows all flow (the first flush) to be discharged to the sewer.Because the flow to the sewer can be optimised at it’s maximum permitted capacitythe attentuation/storage capacity can be reduced over other methods of flow control,thus giving cost savings in storage provision.This is best explained by looking at a singlestorm event and comparing the 3 flow regulation processes as was done independantlyby WRc in the report titled ‘REDUCINGTHE COST OF STORMWATER STORAGE’,Report No. PT1052, March 1995.The chart below represents 50 l/s control and up to4m of head.The area difference between the curves being the detention volume saving.

Typically the volume saving when using a Hydroslide regulatoris between 7% to 40%

Flow Control

Flow control is often required to reduceflooding of downstream sewer networksor receiving water courses.There are anumber of ways to achieve this.TheHydroslide - Float controlled, constantflow regulator, as detailed below is ideallysuited to the providing an efficient andreliable means of flow control.

There are four types of standardHydroslide flow regulators as pictured.

1) Mini

2) HydroLimiter

3) VS - Vertical Standard

4) Combi - self flushing, can be mounted on the dry or wet side of the flow chamber.

Most applications can be dealt with usingany of the four models to suit the flow.An accuracy of +/-5% is achievable.

1

3

4

2

Performance Criteria

Note: Screen apertures of 4.8 mm , 2.4 mm and 1.2 mm are available.

The 4.8 and 2.4 mm screens are generally used for Surface Water applications, withfoul applications using either 2.4 or 1.2 mm aperture units.

Typical 1.2 mm aperture Performance

• shall remove all solids with a single dimension greater than 1.2 mm and positivelycontain those solids until the unit is cleaned.

• shall remove and positively contain 100 percent of all neutrally buoyant particles witha single dimension greater than 1.2 mm for all flow conditions to design capacity.

• shall remove and positively contain 100 percent of all floating trash and debris with asingle dimension greater than 1.2 mm for all flow conditions to the design capacity.

• shall remove a minimum of 50 percent of oil and grease (as defined as the floatingportion of total hexane extractable materials) for all flow conditions to the designcapacity, without the addition of absorbents.

• shall provide the following minimum particle removal efficiencies (based on a specificgravity of 2.65):

a) 100 percent of all particles greater than 1100 microns.

b) 95 percent of all particles greater than 550 microns.

c) 90 percent of all particles greater than 367 microns.

d) 20 percent of all particles greater than 200 microns.

Maintenance

SurfSep maintenance can be site and drainage area specific.The installation should beinspected periodically to assure its condition to handle anticipated runoff. If pollutantloadings are known, then a preventive maintenance schedule can be developed basedon runoff volumes processed.

Since this is seldom the case we recommend;

New Installations

Check the condition of the installation after the first few events.This includes a visual inspection to ascertain that the unit isoperating correctly and measuring the amount of deposition thathas occurred in the unit.This may be achieved using a ‘Dip Stick’.

Ongoing Operation

For the first 12 months the installationssump full volume should be inspectedmonthly and recorded.When the inspectionindicates that the sump full volume isapproaching the top of the sump (base ofscreen) a cleanout should be undertaken.

Cleaning Methods

• Eduction (Suction)

• Basket Removal

• Mechanical Grab

Maintenance Cycle

Minimum once per year. Depending onthe pollutant load it may be necessary tomaintain the installation more frequently.

The operator shall be able to devise themost efficient maintenance schedule forany particular installation over a 12month operating cycle.

Operation & Performance

TM

6

SurfSep Dimensions

SurfSep Dimensions (mm)

SWI0404 SW0604 SW0606 SW0804 SW0806 SW0808 SWI010 SWI012 SWI015A 370 370 370 370 370 370 500 500 500B 444 815 615 810 830 810 800 800 830C 1250 1985 1985 2080 2300 2480 2800 3000 3330D 800 1200 1200 1500 1500 1500 2000 2000 2000E 1112 1665 1665 1966 1966 1966 2475 2475 2475F 400 700 700 700 700 800 1000 1000 1000G (dia) 400 600 600 800 800 800 1000 1000 1000H 400 400 600 400 600 800 1000 1200 1500

In-Line SurfSep Units (SWI)

These units are used with in the drainage system in-line and are supplied as BBAApproved complete Polyethylene Chamber units from the selection table above.

Off-Line SurfSep Units (SWO)

These can be designed either using pre-cast concrete or specially designedPolyethylene chambers.

Model Designation

SurfSep models are firstly identified by the letters SW for Surface Water followed by a letter (I or O) representing the configuration (Inline or Offline).

A four digit number representing the screen diameter and screen height then followsto give the standard model designation for a SurfSep screen for installation intostandard commercially availablepre-fabricated manhole chambersi.e SWI 0806. Example: SWI 0806designates Surface Water Inline with aseparation screen dia 0.8 m and screenheight of 0.6m.

Selection Table - SurfSep

Model ReferenceHydraulic Peak Flow Rate l/s

Drainage Area -Impermeable m2

ChamberDiameter (mm)

Internal Pipe Diameter (mm)

* Proposed Peak Flow Rate for each modelcalculated using Rational Lloyd Davies with a rainfallintensity of 50mm/hr. For greater flows - specialdesign / construction required.

SWI 0404 30 2,000 900 150 / 225

SWI 0604 70 5,000 1200 225

SWI 0606 / 01 140 10,000 1200 225 - 375

SWI 0606 / 02 200 15,000 1200 225 - 375

SWI 0804 275 20,000 1500 300

SWI 0806 350 25,000 1500 450

SWI 0808 400 30,000 1500 450

SWI 1010 480 35,000 2000 450

SWI 1012 550 40,000 2000 450 / 750

SWI 1015 700 50,000 2000 450 / 750

Surfacewatersystem

SurfSep

Attenuationtank

Hydroslideflow control

Outfall

Approved Suppliers

TM

ALLPIPE LIMITED,Vulcan Road South, Norwich NR6 6AFTelephone: 01603 488700 Fax: 01603 488598 Email: sales@allpipe.co.uk

www.althon.net

Illustration: Detention & Retention Systems

SurfSeps unit installed in front of attenuation tank / cellular storage system, toremove grit, fine sediments and floating debris which can accumulate within surfacewater systems. Hydroslide flow control regulating the discharge to the outfall.TheHydroslide can be supplied for installation in an insitu constructed chamber, or as acomplete unit housed within a pre-fabricated polyethylene manhole chamber.

CDS Technologies is a multi disciplined, international, company offering a comprehensiveproduct range of; wastewater treatment technologies and processes, and stormwatermanagement solutions for attenuation, infiltration, flow control and overflow treatment.CDS have an established network of Distributors and Representatives.Further information can be found on our website www.cdstech.com.au Alternatively please contact our approved supplier detailed below.

Surface Water Treatment

* BBA - THIS CERTIFICATE RELATES TO PIPEX UNIVERSALMANHOLES AND ACCESS CHAMBERS,WHICH AREMANUFACTURED FROM WELDED POLYPROPYLENE.This Certificate covers the use of the manholes andchambers for drain and sewer applications where they areused for maintenance to depths of 6 mtrs.

Unit Selection Design Guide

Hydro-Brake® Flow Controls t o r m w a t e r

Modelling Guide

turning water around ...®

Telephone: +353 (0) 1 4013964 • www.hrdtec.com

OverviewHydro-Brake® Flow Controls restrict the flow in surface/storm water or foul/combined sewer systems by inducing a vortex flow pattern in the water passing through the device, having the effect of increasing back-pressure.

Their ‘hydrodynamic’ rather than ‘physical restriction’ based operation provides flow regulation whilst maintaining larger clearances than most other types of flow control, making them less susceptible to blockage. Their unique “S”-shaped head-flow characteristic also enables them to pass greater flows at lower heads, which can enable more efficient use of upstream storage facilities.

This document provides guidance relating to the selection and use of Hydro-Brake® Flow Controls for use in surface/storm water and foul/combined sewer systems.

The information provided here is intended for the purposes of general guidance only - individual application requirements may differ. If in doubt, or to enquire about new product additions, please contact HRD Technologies Ltd.

Hydraulic Characteristics and SpecificationHydro-Brake® Flow Controls should be selected such that the duty/design flow is not exceeded at any point on the head-flow curve, see illustration right. If this is not achievable using the initially selected unit, it may be appropriate to select an alternative option (see selection guidance overleaf).

While the primary aim of a flow control is to provide a particular flow rate at a given upstream head (giving a design/duty point), it is important to note that secondary opportunities, such as potential for optimised storage use, derive from consideration of the full hydraulic characteristic. It is therefore important to ensure that the same flow control, or one confirmed to provide equivalent hydraulic performance, is implemented in any final installation.

To ensure correct implementation a multiple design-point specification, defining the main hydraulic features of the selected flow control, can be provided by HRD Technologies Ltd. This should include at least the following information:

• outlet size and model of Hydro-Brake® Flow Control• definition of the duty/design point (head and flow)• definition of the Flush-Flo™ point (head and flow)• definition of the Kick-Flo® point (head and flow)

To ensure that a drainage system performs as designed, it is strongly recommended that this information is reproduced on any technical specifications.

Typical Hydro-Brake® Head Versus Flow Characteristics

(a)

(b)

(a) Kick-Flo® Point(b) Flush-Flo™ Point

Duty Design Point

Pass Forward Flow (l/s)

Hyd

raul

ic H

ead

(m)

Duty Design Flow

STH Range of Hydro-Brake® Flow Controls

See back cover for details.

IRL HBFC Modelling Guide A1211© HRD Technologies Ltd 2011

This information is for guidance only and not intended to form part of a contract. HRD Technologies Ltd pursues a policy of continual development and reserves the right to amend specifications without prior notice. Equipment is patented in countries throughout the world.

ABCDEF

STH Type Hydro-Brake® Flow Control with BBA Approval

Now included in WinDes® W.12.6!The new STH type Hydro-Brake® Flow Control range has a unique head / discharge performance curve which introduces a very important feature - the Switch-Flo® Point. This point illustrates the unique performance feature of the STH range which can lead to further savings in upstream storage, whilst also enabling increased inlet / outlet size to further reduce the risk of blockage.

Kick-Flo® (a) - the point at which the vortex has initiated and at which the curve begins to return back to follow the orifice curve and reach the same design point or desired head / flow condition.

NEW Switch-Flo® (b) - marks the transition between the Kick-Flo® and Flush-Flo™, from vortex initiation to stabilisation. This point adds a new layer of resolution to the Hydro-Brake® curve that has implications to upstream storage savings.

Flush-Flo™ (c) - the point at which the vortex begins to initiate and have a throttling effect. This point on the Hydro-Brake® curve is usually much nearer to the maximum design flow (Design Point), than other vortex flow controls leading to more water passing through the unit during the earlier stages of a storm, thus reducing the amount of water that needs to be stored upstream.

STH Range of Hydro-Brake® Flow Controls

The STH Hydro-Brake® Flow Control is the only vortex flow control available today that has been given the prestigious BBA Approval Certificate. The BBA assessment procedure entails rigorous assessment of production and manufacturing standards, and confirms that the hydraulic performance of the Hydro-Brake® Flow Control matches the data given to designers by HRD Technologies with their head / discharge curves.

turning water around ...®

Typical STH Head Versus Flow Characteristics

(a)(b)

(c)

(a) Kick-Flo® Point(b) Switch-Flo® Point(c) Flush-Flo™ Point

Design Point

Pass Forward Flow (l/s)

Hyd

raul

ic H

ead

(m)

A worked example showing the steps to model a Hydro-Brake® Flow Control and associated Stormcell® Storage System within Micro Drainage WinDes® is available on our website:

www.hrdtec.com

Engineering Nature’s Way is a brand new resource for people working with Sustainable Drainage and flood management in the UK.

The site provides an opportunity to share news, opinion, information and best practice for people working in local and central Government; developers, consulting engineers and contractors. Do you have something to share? We would be delighted to receive your contributions.

www.engineeringnaturesway.co.uk

Take a Look at Our New Stormwater Web Resource

HRD Technologies Ltd • Tootenhill House • Rathcoole • Co. Dublin • IrelandTel: +353 (0) 1 4013964 • Fax: +353 (0) 1 4013978 • www.hrdtec.com

HRD Technologies Ltd is a subsidiary of Hydro International plc

DIRECT

0800 774 7650info@greenroofsdirect.com

146 Shore Road , MagheramorneLarne, Co. Antrim BT40 3HY

Green roofs Direct

extensive sedum roof Build Up specification

extensive sedum roof Build Up specificationconsisting of: Protective Fleece, Drainage Layer, Growing Medium

and Pre Grown Sedum Blanket

Drainage LayerProduct DescriptionDrainage Layer is made of cross-linked, closed cell polyethylene (PE) foam flakes, which are connected together by thermal processing. The already applied/laminated filter fleece is made of polyester (PET) fibres.

Uses:Drainage Layer is used as a drainage, protection, filter and root expansion layer for extensive green roof systems on flat roofs.

characteristics / Advantages

4 in 1 product (drainage, protection, filter and root expansion layer)

Light and easy to cut

Suitable for low pitch roofs

High porosity and very high water transmissibility

Drainage Layer does not rot

Compressive strength

Recyclable

tests Approvals / standards Quality management system EN ISO 9001/14001Reaction to fire according to EN 13501-1, class E

Product Data:Appearance Surface: structuredColour Drainage layer: coloured Filter fleece: light grey Packaging, Packing unit: 40 pieces per pallet (90 m2)Storage Conditions Drainage Layer shall be stored at dry conditions.Shelf-Life Drainage Layer does not expire during correct storage.

DIRECT

Drainage Layer:

technical DataMaterial Bases

Drainage layer: Polyethylene foam (PE) Filter fleece: Polyester fibres (PET)

Length 2.25 m (± 3 %)

Width: 1.00 m (± 3 %) Thickness: 25 mm (- 0 mm / + 3 mm)

Mass per unit area EN 9864

Drainage layer: 2100 g/m2 (- 120 g / + 100 g)Filter fleece: 145 g/m2 (- 3 g / + 5 g)

static puncture EN 12236

Drainage layer: 1800 N Filter fleece: 1600 N

Water permeability EN 11058 normal to the plane (V H50) 0.11 m/s (± 0.01)

Application conditions / Limits:temperature The use of Drainage Layer 30 is limited to geographical locations

with average monthly minimum temperatures of -50 °C. Permanent ambient temperature during use is limited to +50 °C.

DIRECT

Growing Medium:install 50mm multi-layer extensive roof substrate composed of mineral

bulk mixture with a proportion of mineral and organic matter.

total pore volume > 60-70 Vol %

Max water capacity ≥ 35% Vol

Key data

Dry weight approx. ≤ .75 g/cm3Water saturated ≤ 1.4g/cm3

organic content ≥65 g/L

pH value 5.8-7.9

Water permeability ≥ 0.6 mm/min

compression factor 1,2

Vegetation Layer:Please see data sheet for information

ecology, Health and safety information

The product does not fall within the EC-regulation of hazardous goods. As a result, a material safety data sheet following EC-Guideline 91/155 EWG is not needed to bring the product to the market, transport or use it. The product does not damage the environment when used as specified.

DIRECT

sedum Blanket Datasheet:carrier Predominately rottable Cocomat with geo textile weave

substate Locally produced mix containing at least 25% recycled green waste

Vegetation

compostion Sedum Acre Aureum, Sedum Album Coral Carpet, Sedum Album mini, Sedum Album Athoum, Sedum Hispanicum, Sedum Summer Glory, Sedum Reflexum, Sedum Weihenstephaner Gold, Sedum Voodoo

Vegetation coverage Vegetation coverage

thickness 2.5cm -4.5cm

Water saturation weight 18-22 kg /m²

standard size 1 m x 1.5 m

DIRECT

Discharge Units Calculation

INPUT FOR FOUL SEWER NETWORK DESIGN

Project: RESIDENTIAL DEVELOPMENT AT DAVITT ROAD, DRIMNAGH,

Project Ref: D1546

BLOCK A

GROUND FLOOR PLAN: Discharge Units No

WB 1 28 28

WC 7 28 196

BATH 7 28 196

SINK 6 18 108

TOTAL: 528

1ST FLOOR PLAN: Discharge Units No

WB 1 29 29

WC 7 29 203

BATH 7 29 203

SINK 6 18 108

TOTAL: 543

2ND FLOOR PLAN: Discharge Units No

WB 1 29 29

WC 7 29 203

BATH 7 29 203

SINK 6 18 108

TOTAL: 543

3RD FLOOR PLAN: Discharge Units No

WB 1 25 25

WC 7 25 175

BATH 7 25 175

SINK 6 16 96

TOTAL: 471

4TH FLOOR PLAN: Discharge Units No

WB 1 25 25

WC 7 25 175

BATH 7 25 175

SINK 6 16 96

TOTAL: 471

5TH FLOOR PLAN: Discharge Units No

WB 1 22 22

WC 7 22 154

BATH 7 21 147

SINK 6 14 84

TOTAL: 407

6TH FLOOR PLAN: Discharge Units No

WB 1 16 16

WC 7 16 112

BATH 7 16 112

SINK 6 9 54

TOTAL: 294

TOTAL NO OF DICHARGE UNITS FOR FRONT BLOCK: 3257

Client: Brian M Durkan & Co. Ltd

DUBLIN 12

INPUT FOR FOUL SEWER NETWORK DESIGN

Project: RESIDENTIAL DEVELOPMENT AT DAVITT ROAD, DRIMNAGH,

Project Ref: D1546

BLOCK B

GROUND FLOOR PLAN: Discharge Units No

WB 1 9 9

WC 7 11 77

BATH 7 8 56

SINK 6 8 48

RETAIL UNITS 8 1 8

TOTAL: 198

1ST FLOOR PLAN: Discharge Units No

WB 1 29 29

WC 7 29 203

BATH 7 29 203

SINK 6 18 108

TOTAL: 543

2ND FLOOR PLAN: Discharge Units No

WB 1 29 29

WC 7 29 203

BATH 7 29 203

SINK 6 18 108

TOTAL: 543

3RD FLOOR PLAN: Discharge Units No

WB 1 25 25

WC 7 25 175

BATH 7 25 175

SINK 6 16 96

TOTAL: 471

4TH FLOOR PLAN: Discharge Units No

WB 1 25 25

WC 7 25 175

BATH 7 25 175

SINK 6 16 96

TOTAL: 471

5TH FLOOR PLAN: Discharge Units No

WB 1 21 21

WC 7 21 147

BATH 7 21 147

SINK 6 14 84

TOTAL: 399

6TH FLOOR PLAN: Discharge Units No

WB 1 18 18

WC 7 18 126

BATH 7 18 126

SINK 6 11 66

TOTAL: 336

TOTAL NO OF DICHARGE UNITS FOR FRONT BLOCK: 2961

Client: Brian M Durkan & Co. Ltd

DUBLIN 12

INPUT FOR FOUL SEWER NETWORK DESIGN

Project: RESIDENTIAL DEVELOPMENT AT DAVITT ROAD, DRIMNAGH,

Project Ref: D1546

BLOCK C

GROUND FLOOR PLAN: Discharge Units No

WB 1 8 8

WC 7 8 56

BATH 7 8 56

SINK 6 6 36

TOTAL: 156

1ST FLOOR PLAN: Discharge Units No

WB 1 12 12

WC 7 12 84

BATH 7 12 84

SINK 6 8 48

TOTAL: 228

2ND FLOOR PLAN: Discharge Units No

WB 1 12 12

WC 7 12 84

BATH 7 12 84

SINK 6 8 48

TOTAL: 228

3RD FLOOR PLAN: Discharge Units No

WB 1 8 8

WC 7 8 56

BATH 7 8 56

SINK 6 8 48

TOTAL: 168

TOTAL NO OF DICHARGE UNITS FOR FRONT BLOCK: 780

Client: Brian M Durkan & Co. Ltd

DUBLIN 12

INPUT FOR FOUL SEWER NETWORK DESIGN

Project: RESIDENTIAL DEVELOPMENT AT DAVITT ROAD, DRIMNAGH,

Project Ref: D1546

BLOCK D

GROUND FLOOR PLAN: Discharge Units No

WB 1 12 12

WC 7 12 84

BATH 7 12 84

SINK 6 8 48

TOTAL: 228

1ST FLOOR PLAN: Discharge Units No

WB 1 12 12

WC 7 12 84

BATH 7 12 84

SINK 6 8 48

TOTAL: 228

2ND FLOOR PLAN: Discharge Units No

WB 1 12 12

WC 7 12 84

BATH 7 12 84

SINK 6 8 48

TOTAL: 228

3RD FLOOR PLAN: Discharge Units No

WB 1 6 6

WC 7 6 42

BATH 7 6 42

SINK 6 6 36

TOTAL: 126

TOTAL NO OF DICHARGE UNITS FOR FRONT BLOCK: 810

Client: Brian M Durkan & Co. Ltd

DUBLIN 12

Foul Sewer Network Design

2.000

1.001

1.000

2.0002.0

01

2.002

2.004

2.005

2.003

3.000

3.001

3.002

CONNECT TO THE EXISTING COMBINEDSEWER 1500mm PIPE AT DAVIT ROADPROPOSED CROWN CONNECTION - IL. 25.515

FS MH04DISCHARGE

MANHOLE

1.003

EXISTING COMBINED SEWER 1500mm

EXISTING 300 CONCRETE

1.002

Burke Jenkins Page 1

Consulting Engineers Residential Development

21 Cookstown Ind Est DAVITT ROAD

Tallaght Dublin 24 Dublin 12

Date 14-12-2018 Designed By ED

File D1546 - Foul PL2.fws Checked By

CADS Foul W.7.3 (c)1982-2000 Micro Drainage

FOUL SEWERAGE DESIGN

Network Design Table

Industrial Flow (l/s/ha) 0.00 O'flow Setting (*Foul only) 0Industrial Peak Flow Factor 0.00 Infiltration % 0Calculation Method BS 8301 Minimum Backdrop Height (m) 0.050Frequency Factor 0.00 Depth from Soffit to G.L. (m) 1.200Domestic (l/s/ha) 0.00 Min Vel. (m/s - Auto Design Only) 0.75Domestic Peak Flow Factor 0.00 Min Slope (1:X - Optimisation) 500

Designed with Level Soffits

Network Design Table

PN

Length(m)

Fall(m)

Slope(1:X)

Area(ha)

Units

DWF(l/s)

k(mm)

HYDSECT

DIA(mm)

1.000 45.00 0.525 85.7 0.000 672.0 0 1.500 o 2251.001 63.00 0.725 86.9 0.000 2138.0 0 1.500 o 225

2.000 17.00 0.325 52.3 0.000 273.0 0 1.500 o 2252.001 10.50 0.225 46.7 0.000 147.0 0 1.500 o 2252.002 11.00 0.225 48.9 0.000 126.0 0 1.500 o 2252.003 13.00 0.125 104.0 0.000 378.0 0 1.500 o 2252.004 10.50 0.100 105.0 0.000 588.0 0 1.500 o 2252.005 27.00 0.250 108.0 0.000 273.0 0 1.500 o 225

1.002 38.00 0.650 58.5 0.000 0.0 0 1.500 o 225

3.000 45.00 0.325 138.5 0.000 840.0 0 1.500 o 2253.001 17.00 0.325 52.3 0.000 882.0 0 1.500 o 225

4.000 45.00 0.400 112.5 0.000 1767.0 0 1.500 o 225

Network Results Table

PN

US/IL(m)

E.Area(ha)

E.DWF(l/s)

E.Units

Infil.(l/s)

P.Dep(mm)

P.Vel(m/s)

Vel(m/s)

CAP(l/s)

Flow(l/s)

1.000 27.900 0.000 0 672.0 0 57 0.87 1.24 49 71.001 27.375 0.000 0 2810.0 0 82 1.06 1.23 49 14

2.000 27.900 0.000 0 273.0 0 43 0.95 1.59 63 52.001 27.575 0.000 0 420.0 0 45 1.03 1.68 67 62.002 27.350 0.000 0 546.0 0 47 1.04 1.64 65 62.003 27.125 0.000 0 924.0 0 64 0.84 1.13 45 82.004 27.000 0.000 0 1512.0 0 72 0.90 1.12 45 102.005 26.900 0.000 0 1785.0 0 76 0.91 1.10 44 11

1.002 26.200 0.000 0 4595.0 0 88 1.34 1.50 60 19

3.000 26.300 0.000 0 840.0 0 67 0.75 0.97 39 73.001 25.975 0.000 0 1722.0 0 62 1.18 1.59 63 10

4.000 26.350 0.000 0 1767.0 0 76 0.90 1.08 43 11

Burke Jenkins Page 2

Consulting Engineers Residential Development

21 Cookstown Ind Est DAVITT ROAD

Tallaght Dublin 24 Dublin 12

Date 14-12-2018 Designed By ED

File D1546 - Foul PL2.fws Checked By

CADS Foul W.7.3 (c)1982-2000 Micro Drainage

Network Design Table

PN

Length(m)

Fall(m)

Slope(1:X)

Area(ha)

Units

DWF(l/s)

k(mm)

HYDSECT

DIA(mm)

3.002 20.00 0.100 200.0 0.000 638.0 0 1.500 o 225

1.003 7.00 0.035 200.0 0.000 0.0 0 1.500 o 225

Network Results Table

PN

US/IL(m)

E.Area(ha)

E.DWF(l/s)

E.Units

Infil.(l/s)

P.Dep(mm)

P.Vel(m/s)

Vel(m/s)

CAP(l/s)

Flow(l/s)

3.002 25.650 0.000 0 4127.0 0 120 0.83 0.81 32 18

1.003 25.550 0.000 0 8722.0 0 170 0.92 0.81 32 30

Appendix to Foul Sewer Design Specification/Product Information for:

Petrol Interceptor

ADVANCED

ROTOMOULDE

D

CONSTRUCTI

ON

ON SELECTE

D

MODELS!

SEPARATORSA RANGE OF FUEL/OILSEPARATORS FORPEACE OF MIND

Let us help!Free professional

site visit with friendlysupport and advice.helpingyou@klargester.comto make the right decisionor call 028 302 66799

2

Separators

The Environment Regulators,Environment Agency, England andWales, SEPA, Scottish EnvironmentalProtection Agency in Scotland andDepartment of Environment & Heritagein Northern Ireland, have publishedguidance on surface water disposal,which offers a range of means ofdealing with pollution both at sourceand at the point of discharge from site(so called ‘end of pipe’ treatment).These techniques are known as‘Sustainable Drainage Systems’ (SuDS).

Where run-off is draining from relatively low risk areas such as car-parks andnon-operational areas, a source controlapproach, such as permeable surfaces orinfiltration trenches, may offer a suitablemeans of treatment, removing the needfor a separator.

Oil separators are installed on surface waterdrainage systems to protect receivingwaters from pollution by oil, which may bepresent due to minor leaks from vehiclesand plant, from accidental spillage.

Effluent from industrial processes andvehicle washing should normally bedischarged to the foul sewer (subject tothe approval of the sewerage undertaker)for further treatment at a municipaltreatment works.

SEPARATOR STANDARDSAND TYPESA British (and European) standard(EN 858-1 and 858-2) for the designand use of prefabricated oil separatorshas been adopted. New prefabricatedseparators should comply with thestandard.

SEPARATOR CLASSESThe standard refers to two ‘classes’ ofseparator, based on performance understandard test conditions.

CLASS IDesigned to achieve a concentration ofless than 5mg/l of oil under standard testconditions, should be used when theseparator is required to remove very smalloil droplets.

CLASS IIDesigned to achieve a concentration ofless than 100mg/l oil under standard testconditions and are suitable for dealing withdischarges where a lower qualityrequirement applies (for example wherethe effluent passes to foul sewer).

Both classes can be produced as fullretention or bypass separators. The oilconcentration limits of 5 mg/l and 100 mg/lare only applicable under standard testconditions. It should not be expected thatseparators will comply with these limitswhen operating under field conditions.

FULL RETENTION SEPARATORSFull retention separators treat the full flowthat can be delivered by the drainagesystem, which is normally equivalent to theflow generated by a rainfall intensity of65mm/hr.

On large sites, some short term floodingmay be an acceptable means of limitingthe flow rate and hence the size of fullretention systems.

BYPASS SEPARATORSBypass separators fully treat all flowsgenerated by rainfall rates of up to6.5mm/hr. This covers over 99% of allrainfall events. Flows above this rate areallowed to bypass the separator. Theseseparators are used when it is consideredan acceptable risk not to provide fulltreatment for high flows, for examplewhere the risk of a large spillage and heavyrainfall occurring at the same time is small.

FORECOURT SEPARATORSForecourt separators are full retentionseparators specified to retain on site themaximum spillage likely to occur on apetrol filling station. They are required forboth safety and environmental reasons andwill treat spillages occurring during vehiclerefuelling and road tanker delivery. The sizeof the separator is increased in order toretain the possible loss of the contents ofone compartment of a road tanker, whichmay be up to 7,600 litres.

SELECTING THE RIGHTSEPARATORThe chart on the following page givesguidance to aid selection of theappropriate type of fuel/oil separator foruse in surface water drainage systemswhich discharge into rivers andsoakaways.

For further detailed information, pleaseconsult the Environment Agency PollutionPrevention Guideline 03 (PPG 3) ‘Use anddesign of oil separators in surface waterdrainage systems’ available from theirwebsite.

Klargester has a specialist team whoprovide technical assistance in selectingthe appropriate separator for yourapplication.

Surface water drains normally discharge to awatercourse or indirectly into underground waters(groundwater) via a soakaway. Contamination ofsurface water by oil, chemicals or suspended solidscan cause these discharges to have a seriousimpact on the receiving water.

Get in touch for a FREEprofessional site visit and a

representative will contact youwithin 5 working days to

arrange a visit.helpingyou@klargester.comto make the right decisionor call 028 302 66799

3

Source controlSuDS should

be consideredwhere possible

The use of SuDS should be considered at all sites and they shouldbe incorporated where suitable. SuDS can be used to polish the

effluent from these separators before it enters the environment6

Yes

Yes

Yes Yes No

Is there risk of oilcontaminating the

drainage from the site?

Risk ofinfrequent lightcontaminationand potential

for smallspills only,e.g. car park

Source controlSuDS must beconsidered and

incorporatedwhere suitable

Risk of regularcontamination

of surface waterrun off with oiland/or risk oflarger spills,e.g. vehiclemaintenancearea, goods

vehicle parkingor vehicle

manoevering5

Drainage willalso contain

dissolved oils,detergents or

degreaserssuch as vehicle

wash waterand tradeeffluents,

e.g. industrialsites

Fuel oils aredelivered to

and dispensedon site,e.g. retailforecourts

Very low riskof oil

contamination,e.g. roof water

If not suitable

Yes Yes

Yes

Yes

Yes

Clean watershould not be

passed throughthe separator

unless the sizeof the unit is

increasedaccordingly

BypassSeparator withalarm required

Class I ifdischarge to

surface water2,3

Class II ifdischarge tofoul sewer1

Full RetentionSeparator withalarm required

Class I ifdischarge to

surface water2

Class II ifdischarge tofoul sewer1

Trade effluentsmust be

directed to thefoul sewer1

It may need topass througha separator

before dischargeto sewer forremoval of

free oils

Full Retention‘Forecourt’

Separator withalarm required

Class I ifdischarge to

surface water2

Class II ifdischarge to foul

sewer1,4

Separator notrequired

1 You must seek prior permission from your local sewer provider before you decide which separator to install and before you make any discharge.2 You must seek prior permission from the relevant environmental body before you decide which separator to install.3 In this case, if it is considered that there is a low risk of pollution a source control SuDS scheme may be appropriate.4 In certain circumstances, the sewer provider may require a Class 1 separator for discharges to sewer to prevent explosive atmospheres from being generated.5 Drainage from higher risk areas such as vehicle maintenance yards and goods vehicle parking areas should be connected to foul sewer in preference to surface water.6 In certain circumstances, a separator may be one of the devices used in the SuDS scheme. Ask us for advice.

4

UNIT FLOW PEAK FLOW DRAINAGE STORAGE UNIT UNIT DIA. ACCESS BASE TO BASE TO STANDARD MIN. INLET STANDARDNOMINAL (l/s) RATE (l/s) AREA (m2) CAPACITY (litres) LENGTH (mm) (mm) SHAFT INLET INVERT OUTLET FALL ACROSS INVERT PIPEWORKSIZE SILT OIL DIA. (mm) (mm) INVERT (mm) (mm) DIA. (mm)

NSBP003 3 30 1670 300 45 1700 1350 600 1420 1320 100 500 160

NSBP004 4.5 45 2500 450 60 1700 1350 600 1420 1320 100 500 160

NSBP006 6 60 3335 600 90 1700 1350 600 1420 1320 100 500 160

NSBE010 10 100 5560 1000 150 2069 1220 750 1450 1350 100 700 315

NSBE015 15 150 8335 1500 225 2947 1220 750 1450 1350 100 700 315

NSBE020 20 200 11111 2000 300 3893 1220 750 1450 1350 100 700 375

NSBE025 25 250 13890 2500 375 3575 1420 750 1680 1580 100 700 375

NSBE030 30 300 16670 3000 450 4265 1420 750 1680 1580 100 700 450

NSBE040 40 400 22222 4000 600 3230 1920 600 2185 2035 150 1000 500

NSBE050 50 500 27778 5000 750 3960 1920 600 2185 2035 150 1000 600

NSBE075 75 750 41667 7500 1125 5841 1920 600 2235 2035 200 950 675

NSBE100 100 1000 55556 10000 1500 7661 1920 600 2235 2035 200 950 750

NSBE125 125 1250 69444 12500 1875 9548 1920 600 2235 2035 200 950 750

Rotomoulded chamber construction GRP chamber construction * Some units have more than one access shaft – diameter of largest shown.

Advanced

rotomoulded

constructio

n

on selected

models

• Compact and

robust

• Require less

backfill

• Tough, lightw

eight and

easy to hand

le

APPLICATIONBypass separators are used when it is considered an acceptable risk

not to provide full treatment, for very high flows, and are used, for

example, where the risk of a large spillage and heavy rainfall occurring

at the same time is small, e.g.

■ Surface car parks.

■ Roadways.

■ Lightly contaminated commercial areas.

PERFORMANCEKlargester were one of the first UK manufacturers to have separators

tested to EN 858-1. Klargester have now added the NSB bypass

range to their portfolio of certified and tested models. The NSB number

denotes the maximum flow at which the separator treats liquids.

The British Standards Institute (BSI) tested the required range of

Klargester full retention separators and certified their performance in

relation to their flow and process performance assessing the effluent

qualities to the requirements of EN 858-1. Klargester bypass separator

designs follow the parameters determined during the testing of the

required range of bypass separators.

Each bypass separator design includes the necessary volume

requirements for:

■ Oil separation capacity. ■ Oil storage volume.

■ Silt storage capacity. ■ Coalescer.

The unit is designed to treat 10% of peak flow. The calculated drainage

areas served by each separator are indicated according to the formula

given by PPG3 NSB = 0.0018A(m2). Flows generated by higher rainfall

rates will pass through part of the separator and bypass the main

separation chamber.

Class I separators are designed to achieve a concentration of 5mg/litre

of oil under standard test conditions.

Bypass

SIZES AND SPECIFICATIONS

Class II separators are designed

to achieve a concentration of 100mg/litre

of oil under standard test conditions.

FEATURES■ Light and easy to install.

■ Class I and Class II designs.

■ Inclusive of silt storage volume.

■ Fitted inlet/outlet connectors.

■ Vent points within necks.

■ Oil alarm system available (required by EN 858-1 and PPG3).

■ Extension access shafts for deep inverts.

■ Maintenance from ground level.

■ GRP or rotomoulded construction (subject to model).

To specify a nominal size bypass separator, the following information is

needed:-

■ The calculated flow rate for the drainage area served. Our designsare based on the assumption that any interconnecting pipeworkfitted elsewhere on site does not impede flow into or out of theseparator and that the flow is not pumped .

■ The required discharge standard. This will decide whether a Class Ior Class II unit is required.

■ The drain invert inlet depth.

■ Pipework type, size and orientation.

Issue No. 20: August 2014

COMMERCIAL WASTEWATER SOLUTIONS■ BIODISC®, BIOTEC™ & ENVIROSAFE

HIGH PERFORMANCE SEWAGE TREATMENT SYSTEMS

■ HILLMASTER PACKAGE PUMP STATIONS

■ PUMPSTOR24 PUMPING SYSTEMS

■ STORMWATER ATTENUATION SYSTEMS

■ OIL/WATER SEPARATORS

■ BELOW GROUND STORAGE TANKS

■ GREASE & SILT TRAPS

NEW BUILD & RETROFIT SOLUTIONS■ BELOW GROUND RAINWATER HARVESTING SYSTEMS

■ ABOVE GROUND RAINWATER HARVESTING SYSTEMS

KlargesterUK: College Road North, Aston Clinton, Aylesbury, Buckinghamshire HP22 5EW

Tel: +44 (0) 1296 633000 Fax: +44 (0) 1296 633001 Scottish Office: Tel: +44 (0) 1355 248484email: info@klargester.com

Ireland: Unit 1a, Derryboy Road, Carnbane Business Park, Newry, Co. Down BT35 6QH

NI Tel : +44 (0) 28 302 66799 Fax: +44 (0) 28 302 60046 ROI Tel: 048 302 66799 Fax: 048 302 60046email: info@klargester.ie

Visit our website www.klargester.com, or our company website www.kingspanenv.com

In keeping with Company policy of continuing research and development and in order to offer our clients the most advanced products,Kingspan Environmental reserves the right to alter specifications and drawings without prior notice.

Part of

PROFESSIONAL INSTALLERSKlargester Accredited InstallersExperience shows that correct installationis a prerequisite for the long-lasting andsuccessful operation of any wastewatertreatment product. This is why using aninstaller with the experience and expertiseto install your product is highly recommended.

Services include :

■ Site survey to establish ground conditions and soil types ■ Advice on system design and product selection ■ Assistance on gaining environmental consents and

building approvals ■ Tank and drainage system installation ■ Connection to discharge point and electrical networks ■ Waste emptying and disposal

Discover more about the Accredited Installers and locateyour local expert online.

www.klargester.com/installers

CARE & MAINTENANCEKingspan Environmental ServicesWho better to look after your treatmentplant than the people who designed andbuilt it?

Kingspan Environmental have a dedicatedservice division providing maintenance forwastewater products.

Factory trained engineers are available for site visits aspart of a planned maintenance contract or on a one-offcall out basis.

To find out more about protectingyour investment and ensuringpeace of mind, call us on:

0844 846 0500

or visit us online:www.kingspanenvservice.com