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ACO StormBrixx - Stormwater attenuation and infiltration system
Specification and technical data
UniclassL2123 + JR12 + JS10+ L71121 + L731
EPICJ3413
CI/SfB(52.5)
ACO StormBrixx
ACO Water Management:Civils + Infrastructure
For more information please visit www.stormbrixx.co.uk
2
Introduction to the ACO Group
Throughout the world ACO brandeddrainage and surface water managementsystems are recognised for theirinnovative design, high qualitymanufacture, environmental excellenceand industry leading performance.
Today the ACO Group has a research andproduction base that reaches across fourcontinents. This unmatched resourcepioneers the development of solutionsthat are tailored to individualapplications, meeting the need for highperformance, sustainable products thatdeliver optimum value throughout theiroperational life.
ACO Technologies plc
ACO operates as ACO Technologies plc inthe United Kingdom. Founded over 25years ago, the company has grownquickly on a reputation for designinnovation and customer service.
There are 5 divisions within ACOTechnologies that serve every sector ofthe construction industry, providingsolutions for applications as diverse asrail, highways, airports, landscaping,retail, distribution centres andenvironmentally sensitive projects.
To help architects, designers andcontractors meet the legal requirementsthat now tightly control the way surfacewater is managed, ACO has created itsunique ‘Surface Water ManagementCycle’ – Collect, Clean, Hold, Release –the four core processes required for thecomplete and sustainable management ofsurface water drainage.
The ACO group / www.aco.com
ACO StormBrixx
3
Introduction to ACO StormBrixx 4
ACO StormBrixx attenuation and infiltration system layout 6
ACO StormBrixx main components 8
ACO StormBrixx access chamber 10
ACO StormBrixx accessories overview 12
ACO StormBrixx technical data 13
ACO StormBrixx geotextiles and geomembranes specification data 16
ACO StormBrixx geotextiles and geomembrane selection guide 17
Designing an ACO StormBrixx system 18
ACO StormBrixx system configurations 20
Preparing the system for installation 24
Installation details 26
Step by step installation guide 28
Maintenance and inspection guidance 32
Specification clause 32
Product testing 33
ACO’s sustainable water management system 34
Contents
4
What is ACO StormBrixx?
Plastic geocellular systems are a widelyaccepted method of creating infiltrationand attenuation systems throughout theUK. They have been installed in a varietyof applications for a number of years.
One drawback of these types of systemsis an overall lack of accessibility formaintenance. Improving accessibilitywould enable Local Authorities and WaterCompanies to adopt them.
ACO StormBrixx has been developed tosatisfy these adoption needs and theongoing maintenance requirements ofprivate drainage installations.
The Flood and Water Management Act2010 now gives overall ownershipresponsibilities for SUDS systems to LocalAuthorities. As part of the NationalStandards within the Act, adoptingauthorities are required to maintain andensure ongoing operation of allsustainable drainage systems -requirements which cannot be met bymost current geocellular systems.
ACO StormBrixx addresses the primaryadoption needs of the Local Authorities byproviding true 3D access for inspectionand maintenance, whilst retaining thestructural integrity of the installation.
The system can form part of the design ofany integrated drainage scheme, such asopen parking areas, commercial premises,retail or residential developments.
The ACO StormBrixx system
The ACO StormBrixx systemconsists of a single recycledpolypropylene body that can beassembled in a variety of waysto form an open bonded structure.
ACO StormBrixx’s unique pillarconfiguration gives a high void ratio of95%. This minimises the excavationrequired to achieve a specified storagecapacity, reduces the aggregate neededfor backfilling, and improves the flowcharacteristics of runoff through theinstalled tank.
Side panels are added to the perimeter ofthe system for lateral support and topcovers are added to ensure consistentvertical support for the cover fill material.
ACO StormBrixx benefits from a patentedcell brick and cross bonding featurewhich provides unparalleled stability inthe construction of the tank. Wherebrickbonding is not used or formultilayered tank structures, connectorsare available to support the integrity ofthe structure.
Additional accessories available includeinspection point and pipe connectors,geotextiles and geo-membranes, as wellas a 600 x 600mm access chamber forfull inspection and maintenance.
ACO StormBrixx can be configured tominimise silt accumulation and has theadded feature of a low flow and draindown facility ensuring that the system canbe properly maintained throughout its life.
Introduction to ACO StormBrixx
ACO StormBrixx is a unique and patented plastic geocellular stormwater management system.Designed for surface water infiltration and storage, its versatility allows it to be used in applicationsacross all construction environments as a standalone solution or as part of an integrated sustainableurban drainage (SUDS) scheme.
ACO StormBrixx
5
Structural Integrity
The ACO StormBrixx system has beenindependently tested to certify thestructural integrity and the long term lifeexpectancy of the system.
The patented brickbonding and crossbonding feature provides a strong, longterm installation and also helps to improvethe construction speed of the tank.
Access and maintenance
ACO StormBrixx addresses thefundamental requirement of access andmaintenance for SUDS Approval Boards(SABS) and water companies. The opencell structure permits completely freeaccess for CCTV and jetting equipmentwhich allows the whole system, includingall the extremities, to be inspected andmaintained from just a few access points.
Simplified handling and logistics
ACO StormBrixx simplifies delivery, sitelogistics and installation as a result of itsstackable design. Each single injectionmoulded body nestles, optimisinglogistical and installation costsignificantly, thus helping to reduce thecarbon footprint of the system.
System benefits
! Brick bonded and cross bondingstacking for optimum stability
! Low flow, draindown and siltmanagement facility
! 3D inspection access to tank interior
! Environmentally efficient solution,minimising carbon emissions inmanufacture, transportation and on-site assembly
! High void ratio minimises excavation volume
! Fully certified performance
! Manufactured from recycled andrecyclable polypropylene
! Suitable for all industrial, commercialand residential applications includinghighways
If you need help with specification, design or installation, or just wish to learn more about this and other Surface WaterManagement products from ACO, contact our free, no obligation ACO Water Management Design Services Team who canprovide advice and dedicated design support for your project – call 01462 816666 or visit www.aco.co.uk.
i
Definition of an attenuation system
Attenuation is the process of spreading the peak flow of a stormevent over a longer period of time, releasing the water slowly, andmitigating the surge effect downstream.
ACO StormBrixx attenuation and infiltration system layout
ACO StormBrixx
! ACO StormBrixx can be assembled ina variety of different tankconfigurations to satisfy installationand site requirements
! The patented brickbonding andcrossbonding feature delivers a strongand robust tank installation
! Silt management and controlachievable through tank configurationlayout
! The open cell structure providessimple access for remote CCTV andmaintenance equipment to inspect alllevels and areas of the system
! The system has a unique ‘draindown’facility – a simple access and cleanfeature of the tank (Attenuation only)
! Access chamber provides access forcleaning, large pipe diameter inletsand silt management
! Delivery, site logistics and installationare all dramatically simplified, as aresult of the system’s stackable design
! A clip-in 3-way connector improvesthe structural integrity of multilayeredtank structures and wherebrickbonding is not used
! Inspection point for camera or jettingequipment
ACO StormBrixxlayer connector
ACO StormBrixxtank bodies
ACO StormBrixxside panels
ACOWrapgeomembrane
ACOTex Plusprotection fleece
Outlet pipe
Inlet pipe
Low flow /draindownfacility
ACO StormBrixxinspection point
ACO StormBrixxaccess chamber
ACO StormBrixxaccess chamber
ACO StormBrixxinspection point
ACO StormBrixx top cover
ACO StormBrixx has a range of key features which are common to both attenuation and infiltration systems and are listed below. ACO StormBrixx attenuation and infiltration systems also have a set of features specific to their configuration. These features arehighlighted on the product images below.
ACO StormBrixx attenuation system features
6
! Clear column ‘pathways’ simplifycleaning
! Smooth surfaces prevent silt build-up
! Top covers support infill material
! Clip-in 3-way connector and thecrossbonding feature permits off siteconstruction of the system
The stackable designreduces transportation costsand improves the carbonfootprint of the product
Example: 280m3 storage volume is required for project A. Using ACOStormBrixx the project requirement can be transported on asingle vehicle whereas up to four vehicles may be required forother comparable systems.
7
Definition of an infiltration system
Infiltration is the passage of water through a myriad of voids in thereceiving ground strata. The process includes sedimentation andbiodegradation, freeing the water from impurities.
ACO StormBrixxlayer connector
ACO StormBrixxtank bodies
Inlet pipe
Sedimentforebay
ACO StormBrixxside panels
ACOTex geotextileprotection fleece
ACO StormBrixxinspection point
ACO StormBrixx top cover
ACO StormBrixx infiltration system features
Side panels
Recycled polypropylene side panels areadded to the perimeter of the system togive lateral support against surroundingsoils.
Layer connectors
Clip-in connectors are available to aid thealignment and installation of single anddouble layer ACO StormBrixxconfigurations.
8
ACO StormBrixx
Lightweight design foreasy manual handlingand fast installation
High strengthribbed columns
Recycled polypropyleneconstruction provides tough, highlycorrosion resistant structure
Access grooveprovides a clear pathfor inspection camerasor jetting equipment
ACO STORMBRIXX MAIN COMPONENTS
9
Side walls create debris and silt traps and provideadditional lateral support
High voidratio – 95%
Weep holes providedto maximise void ratio
Units can be cut inhalf to accommodatetank configurations
Two injection mouldedbodies clip together toform one single tank unit
Top covers
Recycled polypropylene top covers areadded to the top layer of the system toensure consistent vertical support for thecover fill material.
Inspection points
An Ø225mm inspection point connectorprovides access for remote CCTV andjetting equipment from the surface of thesystem to different levels and areas of thetank installation.
10
ACO StormBrixx access chamber
ACO StormBrixx
Unit and pipes are shown for illustration purposes only. ACO StormBrixx tank units and pipes are sold separately from the access chamber modules.
Cuts outs for ventilation
Extension shaftExtension shaft
Pipeconnections
The access chamber is designed toprovide complete 3D access to any ACOStormBrixx system for simple inspectionand maintenance. The modular stackablechamber is designed to be incorporatedinto any ACO StormBrixx attenuation orinfiltration system, and forms an integralpart of the system’s overall volume,removing the need for expensiveupstream catch pit manholes.
Each ACO StormBrixx access chambermodule provides 150mm, 225mm,300mm and 375mm inlet and outletpipe connections, reducing the need forexpensive and time-consuming manifoldconnections.
A 375mm cut can be made in the ACOStormBrixx access chamber module toenable complete inspection of all levelsand areas of the system. A 100mm or150mm vent can be created by removingthe cut outs provided in the top half ofthe access chamber.
Cover and frame
A Load Class D 400 Ø450mm solidductile iron cover and frame is availableto complete the ACO StormBrixx accesschamber installation.
An ACO StormBrixx accesschamber module
Perimeter of the ACO StormBrixxaccess chamber
Ø375mm cutout for access
Pipe connections
Low flow and drain downfeature
The ACO StormBrixx access chamberprovides the ability to create a lowflow and drain down facility (as belowand on page 26). This functionenables the system to be drained andsediment and debris removed as partof the maintenance program.
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11
The access chamber enables all levelsand areas of the ACO StormBrixxstructure to be inspected by eithertracked or push rod CCTV inspectionequipment. Where required, the ACOStormBrixx system can be jetted usingstandard equipment.
When the ACO StormBrixx access chamberhas been configured to create a low flowdraindown channel (see page 10) or a silttrap (see page 27), the unit allows for theremoval of silt and debris.
Cutting the unit for pipeconnections
Making pipe connections Cutting the base for a multilayered access chamber
Inlet and outlet pipe connections areprovided on each side of the accesschamber module. Depending on thepipework requirements, cut and removethe appropriate panel. Recessed cuttinglines are provided for guidance. Secondlyremove 375mm panels from each side ofthe unit requiring access.
Push up to 65mm of the pipework intothe access chamber module.
If using more than one access chambermodule in a stack, it will be necessary toremove the base from all modules exceptthe base unit. Cut along the recessedcutting line provided and remove base.
Building the access chamber Adding a raising piece
Once the bases of the upper module(s)have been removed, simply stack theunits on top of each other ensuring thateach module is clipped to the mainstructure using the ACO StormBrixx layerconnectors.
Layer connectors should be incorporatedbefore the next module is added to theaccess chamber stack.
Once the main access chamber has beenconstructed it will be necessary to add a450mm ID raising piece cut to lengthand placed over the top of the accesschamber unit.
MAINTENANCE AND INSPECTION
12
ACO StormBrixx
ACO StormBrixx accessories overview
ACO StormBrixx has a range of PVC-Upipe connectors available to provideconnection to underground drainagepipework.
Standard features include inlet / outletconnection for Ø110mm, Ø160mm,Ø225mm and Ø300mm pipes andflanged plates to aid connection to theACO StormBrixx system.
Top hats
ACO StormBrixx has a range of flexiblemembrane pipe connectors for use inconjunction with ACOWrap to form pipe seals.
Pipe connectors
Protection fleece - ACOTex Plus
Manufactured from polypropylene thisthick non-woven protection fleece is usedto protect a geomembrane frommechanical damage due to ground andthermal movement. The protection fleeceis placed on the outer side of thegeomembrane. ACOTex Plus can be usedwith ACOWrap or with a weldedgeomembrane system.
Geomembranes - ACOWrap
An impermeable self-install geomembraneusing taped joints for ‘non sensitive’attenuation applications.
For sensitive applications ACO recommendsthe ACO StormBrixx system is installed byACO recommended lining contractors usinga geomembrane system with 100%watertight welded joints.
Geotextiles - ACOTex
A polypropylene permeable non-wovengeotextile, for use in infiltrationapplications. ACOTex permits the passageof water into and out of ACO StormBrixxsystem, and also prevents the entry ofsediment into tanks incorporatingsediment forebays.
An ACO StormBrixx geotextile and geomembrane selection guide and typical examples can be found on pages 16 - 17.i
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Technical data
*1 assembled tank unit consists of:
2 x tank bodies
No. of assembled units per m3
2.28
Gross storagevolume m!
0.439
Nett storageVolume m!
0.417
Void Ratio
95%
ACO StormBrixx tank body*
Length(mm)
Width overall(mm)
Depth overall (mm)
Weight (kg)
Verticalcompressive
strength kN/m"
Lateralcompressive
strength kN/m"
Product code
50m
m
305m
m
600m
m
1200mm
1200 600 305 10 420 90 314020
ACO StormBrixx side panel
578m
m
580mm
580 578 35 1.6 - - 314021
Top cover for ACO StormBrixx (set of 4)
550m
m
550mm
550 550 430.8
(per set)- - 314022
Layer connectors
100 40 46 0.1 - - 314023
14
ACO StormBrixx
Technical data
Access chamber moduleLength(mm)
Width overall(mm)
Depth overall (mm)
Weight (kg) Product code
594 594 610 32 27034
Access chamber Ø450mm ductile iron cover Load Class D 400
- Ø528 110 38 27033
Inspection point connector with flange
- Ø225 200 2.5 27018
Inspection point Ø225mm ductile iron cover Load Class D 400
410 410 180 52 27032
600mm 600mm
15
ACO StormBrixx geotextiles
Product code27038
27041
DescriptionACOTex infiltration geotextile
ACOTex Plus protection fleece
Length (m)100
100
Width overall(m)4.0
4.0
Thickness(mm)1.0
2.9
Mass per unitarea (g/m2)125
325
Weight (kg)57 per roll
130 per roll
ACO StormBrixx geotextiles listed above sold per roll. For information on functionality see page 24 and for specification and performance data see pages 16 & 17.
ACO StormBrixx geomembranes
Product code27042
27044
27045
27046
27047
27048
DescriptionACOWrap
ACO double sided butyl mastic tape
Ø110 flexible top hat
Ø160 flexible top hat
Ø225 flexible top hat
Ø300 flexible top hat
Length (m)12.5
15
-
-
-
-
Nominal width overall (mm)4000
100
Ø100
Ø150
Ø225
Ø300
Thickness(mm)0.45
1.5
0.9
0.9
0.9
0.9
Mass per unitarea (g/m2)460
-
-
-
-
-
Weight (kg)23.0
3.70
0.10
0.10
0.10
0.10
ACO StormBrixx geomembranes listed above sold per roll. For details on specification, performance and functionally see pages 16 & 17.
Ø110mm and Ø160mm pipe connector with flangeLength(mm)
Width overall(mm)
Depth overall (mm)
Weight (kg) Product code
- Ø110 - 0.75 27056
- Ø160 - 1.25 27057
Ø225mm and Ø300mm pipe connector with flange
- Ø225 - 1.40 27058
- Ø300 - 1.75 27059
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ACO StormBrixx geotextiles and geomembranes: specification and performance data
ACO StormBrixx
ACOTex Plus protection fleeceProduct code UnitDescription
Material
Sheet dimensions Length (m)
Width (m)
Material thickness (for 2 kPa) (mm)
Material mass per unit area (g/m!)
CBR puncture resistance (N)
Strip tensile strength (md) kN/m
(cd) kN/m
Elongation at maximum load (md)
(cd)
Cone drop test (mm)
Opening size µm
Permeability vertical l/m!/s
27041Mechanically bonded continuous filament non-woven sheet
100% UV stabilised polypropylene
100
4
2.9
325
3850
24
24
100%
40%
15
90
60
ACOTex infiltration geotextile
Product code UnitDescription
Material
Sheet dimensions Length (m)
Width (m)
Material thickness (for 2 kPa) (mm)
Material mass per unit area (g/m!)
CBR puncture resistance (N)
Strip tensile strength (md) kN/m
(cd) kN/m
Elongation at maximum load (md)
(cd)
Cone drop test (mm)
Opening size µm
Permeability vertical l/m!/s
27038Mechanically bonded continuous filament non-woven sheet
100% UV stabilised polypropylene
100
4.0
1
125
1500
9
10
90%
65%
24
105
115
ACOWrap geomembraneProduct code UnitDescription
Sheet dimensions Length (m)
Width (m)
Material mass per unit area (g/m!)
Colour
27042Geomembrane suitable for taped joints
12.5
4
460
Black
A non-sensitive attenuationsystem
ACOWrap is a self-install tapedgeomembrane system which should onlybe used where ground conditions canaccept minor leakages from the tank.ACOWrap should NOT be used insensitive applications such as, but notlimited to:
! Within 5m of any building line
! Where there is a high groundwatertable
! Where land is contaminated or therisk of contamination from surfacewater is high.
ACOWrap accessories:
Tape: A double sided butyl mastic tapeused to join sheets of ACOWrap (Productcode 27044, see page 15 for details).
Top Hats: Flexible membrane pipeconnectors used in conjunction with ACOWrap to form pipe seals (see page 15 for details).
ACOTex Plus is a heavy duty non-wovenprotection fleece used to protectACOWrap against punctures. ACOTex Pluscompletely envelops the ACO StormBrixxsystem and the ACOWrap. ACOTex Pluscan be used with ACOWrap and anyother geomembrane system.
A site-sensitive attenuationsystem
The correct choice of geomembrane isessential to the overall performance ofany attenuation system. In applicationswhere there are site-sensitive issues, ageomembrane with properties similar tothose outlined in the table below shouldbe used and installed by a liningcontractor with UKCAS CSWIPaccreditation.
Site Sensitive applications include, butare not limited to:
! High groundwater table
! Contaminated ground
! Within 5m of any building line
! Where there is a risk of contaminationto groundwater from polluted surfacewaters
An infiltration system
ACOTex is a non-woven polypropylenegeotextile with excellent filtration anddrainage properties used to minimisesediment build up within an ACOStormBrixx infiltration (soakaway) system. ACOTex completely envelops the ACO StormBrixx system as well asthe sediment forebay or tunnel wherespecified.
ACOTex is suitable for infiltration systems only.
ACOTex is simple to install – fitting doesnot require a specialist contractor.
17
ACO StormBrixx geotextiles and geomembrane selection guide
This chart below provides guidance on the selection of wrapping required depending on the systemdesign and the application requirement.
Welded geomembrane: recommended specification Tested PropertyThickness**
Density (max)
Tensile properties (each direction)
Strength at breakElongation at break
Tear resistance
Puncture resistance
Carbon black content
Carbon black dispersion
Unitmm
g/cm3
N/mm2
%
N
N
%
Category
Test MethodASTM D 5199
ASTM D 792 / 1505A
ASTM D 6693, Type IV,Speed: 50mm/min
G.L. = 50mm
ASTM D 1004
ASTM D 4833
ASTM D 1603
ASTM D 5596
Minimum Values*1.0
0.939
27800
100
250
2.0
1/2†
* Value at 95% confidence interval
** Average value of 10 specimens taken across roll width. No value to be less than 90% ofaverage value
† Dispersion only applies to near spherical agglomerates. 9 of 10 views should be category 1 or 2. No more than 1 view from category 3.
Non-sensitive attenuation
ACO WrapACOTex PlusDouble side butyl mastic tapeFlexible top hatPipe connector
Site-sensitive attenuation
Welded geomembrane
Infiltration
ACOTexPipe connector
For further advice, please contact the ACO Water Management Design Services Team - Tel: 01462 816666 Email: [email protected]
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VI
1. Hydraulic design
Hydraulic design looks at the temporarystorage of water in storm events and itsflow path, seeking to reduce the volume,speed, and frequency of surface waterrunoff. All of these factors will be sitespecific. Calculations for hydraulic designshould be undertaken using the methodshighlighted in CIRIA C697 The SUDSmanual.
2. Structural design
Structural design considers the loadbearing capacity of ACO StormBrixx toensure that the installed system cansafely carry the loads it will be subjectedto. The initial decision must be made onthe type of system required, infiltration orattenuation, and then the followingdesign parameters should be considered:
! Soil type
! Vertical and horizontal loading
! Groundwater
! Depth of cover
! Surface finish
Structural calculations should be carriedout using the methodology detailed inCIRIA C680 – “Structural design ofmodular geocellular drainage tanks”. Forfurther advice please consult ACO WaterManagement Design Services Team.
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Designing an ACO StormBrixx system
ACO StormBrixx
Loading design parameters for ACO StormBrixx†
Vertical loading on top face
Lateral loading on side face
Short-term ultimate compressive strength at yield (kN/m2) 420 90
Minimum cover depths(1) over top of ACO StormBrixx
LocationMinimum cover depth (m)(2)
Non-trafficked area i.e. landscaping
Car parks, vehicle up to 2,500kg gross mass
Car parks, occasional vehicle greater than 2,500kg(4) gross mass
0.5(3)
0.6
0.8
(1)Assumes 27 degree load distribution through fill material and overlying surface asphalt or block paving(2)Please check minimum frost cover depths for geographical location(3)Minimum cover depth to avoid accidental damage from gardening / landscaping work(4)Occasional trafficking by refuse collection or similar vehicles (typically one per week)
Maximum installation depths (to base of units)(A). Design criteria in accordance with C680 guidelines*Soil description Typical
angle offriction(B) (C)
Ф
Maximum installation depth (from invert of structure) (m)
No groundwater present Groundwater present1.0m below groundlevel (attenuation)
Traffickedarea(cars only)
Non-trafficked
Traffickedarea(cars only)
Non-trafficked
Over consolidated stiff clay
Silty, sandy clay
Loose sand and gravel
Medium dense sand and gravel
Dense sand and gravel
24
26
30
34
38
3.1
3.3
3.9
4.7
5.6
3.1
3.3
3.9
4.7
5.6
2.3
2.3
2.5
2.6
2.8
2.3
2.3
2.5
2.6
2.8
(A) Design table is only applicable for car parks or other areas trafficked only by cars or occasional refuse collectiontrucks or similar vehicles (typically one per week). Assumptions are made:- ground surface is horizontal- Shear planes and other weaknesses are not present within the structure of the soil
(B) Loosening of dense sand or softening of clay by water can occur during installation. The designer should allowfor any such likely effects when choosing an appropriate value of φ
(C) The design is very sensitive to small changes in the assumed value of φ, therefore, it should be confirmed by achartered geotechnical engineer.
Under the Flood and Water ManagementAct 2010 it will be a planningrequirement for any drainage schemesubmittal to be approved by a localauthority SUDS Approval Board (SAB).
Therefore consultation should occur withthe relevant planning or adopting authorityat the outset in order to determine theirpolicy on the adoption of different SUDSsystems, as this may fundamentally affectthe choice of Sustainable Urban DrainageSystem available.
The local authority, highways authorityand water authority all have powers toadopt ACO StormBrixx systems whereappropriate, and therefore earlyconsultation with the relevant authority isstrongly advised. To design and installACO StormBrixx, specifiers need toconsider three major factors:
1 Hydraulic Design2 Structural Design3 Maintenance
*Available from CIRIA website (www.ciria.org).
†A partial factor of safety materials, Fm, of 2.75 for ultimate limit state and 1.15 for serviceability limited state,should be applied to these values for a design life of 20 years.
19
3. Maintenance
As part of the National Standards withinthe Flood and Water Management Act2010, adopting authorities are requiredto maintain and ensure ongoing operationof all sustainable urban drainage systems.
ACO StormBrixx’s open cell structureaddresses these adoption needs as itpermits completely free access for CCTVand jetting equipment to inspect all levelsand areas of the system. ACO StormBrixxcan limit silt build up within the systemwith the correct design and use of ACOStormBrixx access chamber on allconnecting inlets.
Consideration should be given to siltforebays, sediment tunnels and thedraindown facility at the design stage.
Silt tunnels
Silt tunnels are designed to beincorporated within ‘online’ attenuationsystems. A silt tunnel will direct anyparticles mobilised by stormwater throughthe system to an outlet pipe. The outletpipe is connected to a downstream silt orflow control manhole where the silt anddebris particles are captured andremoved. An inner tunnel is created byadding side panels to a line of cells andwrapping where appropriate with a non-woven geotextile. The choice of geotextileused for the sediment tunnel needs totake into account particle size and thepotential for clogging of the textile.
Low flow and draindown facility
ACO StormBrixx can be configured toensure that the whole system completelydrains down. A line of ACO StormBrixxcompletely encapsulated is added belowthe invert level of the outlet pipe. Withsome other attenuation systems, a smallvolume of water and potentially silt iscontinually trapped due to the depth andpositioning of the tank inlet / outlet andthe cell base layer.
ACO StormBrixx’s draindown facility (seepages 6, 10 & 26) ensures that the systemcompletely drains down to maximise itsstorage volume, whilst retaining themajority of silt in the lower sump where itcan be easily removed. When used inconjunction with a silt tunnel this canbecome an effective method of minimisingsilt build up within the ACO StormBrixxsystem. Conventional systems can becomeclogged with silt over time and reducestorage volumes by between 10-20% overtheir operational life.
Sediment forebays
Sediment forebays are generally used forsoakaway applications and ‘offline’attenuation systems. The forebay isdesigned to capture and hold any silt thathas not been retained in a silt catchpit, orhas been mobilised during a storm, in asmall area of the system where it can beconfined and then removed. A sedimentforebay is created by adding additionalside panels within the tank configurationand adding where necessary a non-wovengeotextile. The choice of geotextile usedfor the forebay needs to take into accountparticle size and the potential for cloggingof the textile.
ACO StormBrixx system configurations
Depending on the design and installation requirements, a variety of unit configurations and tanksizes can be achieved. In its simplest form, a single 1200 x 600 x 610mm unit can be constructedby placing one unit on top of another.
Single unit configurationA single ACO StormBrixx tank body consists of eightcolumns, four with spigots and four with sockets. To createa complete single unit, invert a second tank body andplace it on top of the first. Align the spigot and socketsand push the two bodies together ensuring all columnclips are engaged. Once clipped, the two bodies aredesigned to stay connected.
Brick or cross bondingACO StormBrixx benefits from a patented cell brick andcross bonding feature which provides unparalleled stabilityin the construction of the tank. By utilising this feature, itis possible to create a single layer of interlocked units.
20
ACO StormBrixxConfigurations
Double, treble orquadruple unitconfigurationIt is possible to make a double unit of1200 x 1200 x 610mm, a treble unit1800 x 1200 x 610mm or a quadrupleunit 2400 x 1200 x 610mm
Creating a double unit:Lay two tank bodies side by sideensuring there are no gaps betweenthem and that there are four male orfemale columns in the centre of theconfiguration. Invert two tank bodiesand fix them to the lower tank bodiesin the opposite direction.
Creating a treble unit:Lay two tank bodies side by side and layanother tank body 90° at the end of thefirst two. Ensure there is one block of fourfemale and one block of four malecolumns in the middle of the configuration.
Lay unitsend to end
Indicates cross bonding of tank bodies.Indicates orientation of tank body.
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ACO StormBrixxConfigurations
Cutting the unitIf required, ACO StormBrixx can be cut in half along thecentral rib. A handsaw or jigsaw should be used.
21
Both halves of the unit can be connected to the rest of thesystem using the 3-way connector. Ensure the cut face isorientated towards the inside of the tank system.
Creating a quadruple unit:Lay two tank bodies side by side andanother two tank bodies at a 90° at eitherend of the first two. Depending on whichway the lower units are laid, there shouldeither be one block of four female, oneblock of four male and one block of fourfemale columns in the middle of theconfiguration or vice versa.
To create the top level of the unit, invertfour tank bodies and fix them to thelower tank bodies.
Invert three tank bodies and repeat theabove step turning all three bodies 180°to create the top level of the unit.
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There are multiple ways an ACOStormBrixx system can be configured.These designs depend on a number offactors including the size of the system,site restrictions and the installationtimetable.
Here are two typical ACO StormBrixxsystem configurations which utilise amixture of installation techniques toprovide a simple but strong and robuststructure:
! Perimeter Ring Layout
! Concentric Ring Layout
ACO StormBrixx system configurations
ACO StormBrixx
For this configuration only the perimeterof the system is brick bonded. Theinternal units are a series of single,double, treble, or quadruple units.
1. The installer should ensure that thefootprint of the system is clearlymarked out on the prepared andlevelled base of the excavation. Laygeotextile and/or geomembrane.
2. The perimeter edge of the systemshould now be laid. Place two ACOStormBrixx tank bodies on the ground.Take a third tank body, invert it andplace it in a brick bonded method ontop of the first two bodies. Continuelaying bottom and top bodiesalternately until a completely bondedouter ring is formed. See informationbox below.
3. Assemble single to quadruple units.Assembly methods for these cellconfigurations are provided on pages20-21. Place the units inside theperimeter ring to suit and connect toadjacent units using the ACOStormBrixx layer connector.
4. Repeat for subsequent layers using the connectors to bond layers to oneanother.
Perimeter ring layout
Cross bonding guidancePlease see page 20 and 21 for guidance on creating double, treble or quadruple units.
Brick bonding guidanceTo brick-bond ACO StormBrixx units ensure that the bottom layer of the units is such that there are always two maleor female columns adjacent to one another when laid end to end.
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This is a series of ever decreasing rings converging towards the centre of the system.
1. The installer should ensure that thefootprint of the system is clearlymarked out on the prepared andlevelled base of the excavation. Laygeotextile and /or geomembrane.
2. The perimeter edge of the system shouldnow be laid. Place two ACO StormBrixxtank bodies on the ground. Take a thirdtank body, invert it and place it in a brickbonded method on top of the first twobodies. Continue laying bottom and topbodies alternately until a completelybonded outer ring is formed.
3. This installation method should thenbe repeated to create each internalring. Each ring should be clipped tothe next outer ring using the ACOStormBrixx layer connector. See double vertical and lateralconnection note on page 24.
4. It may be necessary to cut a body tocomplete the bond, particularly as youget towards the centre of the system.See Cutting the unit on page 21.
5. Repeat for subsequent layers using the connectors to bond layers to one another.
Concentric ring layout
3a. Alternatively, due to site limitations, it may be necessary to work from a corner or one end or side. Should this be the case thenfollow step 2 except that you should also commence the inner ring configurations at the same time see images A-C ensuring thatyou use layer connectors where necessary to bond unit ‘rings’ and layers to one another.
A B C
24
Preparing the system for installation
ACO StormBrixx
This section provides guidance on the preparation steps that may be required for the installation of ACO StormBrixx.
Adding the side panels
Push fit the side panel into the slotsprovided in the bottom and top tankbodies ensuring all clips are engaged.Two side panels are required on eachlength and one side panel on each widthof a single cell configuration.
Fitting the pipe connectors
Using a hole saw or jigsaw cut theappropriate diameter hole in the sidepanel of the ACO StormBrixx. The sidepanel has pre-set cut outs for 110 and160mm pipe, and pre-marked eccentriccut outs marked on the inside of the sidepanel to ensure the lowest invert to thetank can be cut. Ensure that the flange ofthe pipe connector does not protrudebelow the invert of the tank.
Fix the connector to the side panelthrough the holes at the corners of theflange. Ensure that the pipe connector isfitted so that there is adequate spigot forthe joining pipework to connect to(minimum 75mm).
The geomembrane or geotextile is thenfixed to the flange by an appropriatemethod to give a firm seal.
Top covers
ACO StormBrixx top covers are onlyrequired on the top surfaces of aninstallation. The top covers ensure theintegrity of the geotextile / geomembraneand the final surface finish of theinstallation. Top covers are supplied as a4-piece unit on a lightweight frame.
They locate easily on the tops of theboxes and need only be lightly pushed into ensure an exact fit.
Lateral unit to unit connection
Align the necessary loose ACO StormBrixxunits next to each other so that the clipholes align. Push the layer connector intothe hole until the clip is properly seated.
Single vertical connection
Snap a layer connector in half and pushthe two ends together to form a singlevertical connector. Place this into thelower unit and then align the top unit andlower into position.
Double vertical and lateral connection
It is possible to connect loose lateral andvertical units by joining layer connectorstogether.
Depending on the ACO StormBrixx designconfiguration, it is possible to useminimum vertical connectors and nolateral connectors. Please consult theACO Water Management Design ServicesTeam for further advice.
Vertical and lateral layer connectors
The ACO StormBrixx connector provides three different connections:
25
Select the ACO StormBrixx unit which willbe used to provide the inspection point.Cut a circular hole in the top tank bodywith a jigsaw. A cutting guide is providedand can be found centred between fourcolumns. Holes should be cut in thesame location on all intermediate top andbottom panels to allow access to alllayers of the tank.
Place a inspection point connector overthe centre of the hole, ensuring the flangecovers all four columns. Using plasticrivets, fix to the ACO StormBrixx unit. Ifan extension piece is required, use225mm twinwall pipe cut to length andfix with a proprietary coupling to theinspection point connector.
Use an ACO StormBrixx Ø225mm ductileiron access cover to complete theinstallation.
Creating an inspection point
The inspection point permits remote access and inspection and where necessary jetting of the system. The access arrangementenables the inspection of all layers within the ACO StormBrixx system.
Section A-A26
Installation details
ACO StormBrixx
ACO STORMBRIXX ATTENUATION SYSTEM
Inlet Outlet
OutletInlet
ACO StormBrixx attenuationsystem with low flow and drain down
The configuration of this ACO StormBrixxsystem is designed to offer the optimallevel of access for maintenance andinspection by providing a tunnel to directsediment and debris through a low flowchannel sump.
Due to the flexibility of the ACO StormBrixxsystem it is possible to create a number ofvariations of this layout – please consultthe ACO Water Management DesignServices department for further options.
In order to create this layout it will benecessary to install both access chambersand the low flow and sediment tunnelfirst, ensuring that the correct aperturesare cut and removed where necessary.
The low flow channel is created byinstalling a row of ACO StormBrixx unitsbelow the design invert of the main tank.This low flow channel volume should notbe included in the calculated volume ofthe tank as it is designed to holdsediment and is therefore sacrificial.
Inlet and outlet connections must bemade above the level of the sump butwithin the height of the sediment tunnel.
The low flow sump and sediment tunnelc/w side panels and 125gsm non wovengeotextile (ACOTex) will need to be fixed tothe rest of the ACO StormBrixx structurewith the connectors. The rest of the ACOStormBrixx structure is installed aroundthe low flow and sediment tunnel.
Inspection points can be located at eachcorner of the tank as required, and canbe used to show the footprint of thesystem after installation. The inspectionpoints allow the extremities and all levelsof the system to be inspected if required.
1
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4
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Section B-B
Section C-C
Individual ACO StormBrixx tank unit
ACO StormBrixx access chamber
ACO StormBrixx inspection point withductile iron cover and frame
ACO StormBrixx tank units completewith side panels wrapped in ACOTexgeotextile to form sediment tunnel
ACO StormBrixx side panels installedaround perimeter of the system
Perimeter of ACO StormBrixx completewith side panels enveloped with weldedgeomembrane layer and protected withACOTex Plus protection fleece.
ACO StormBrixx inspection point withextension raising piece and ductile ironcover and frame
ACO StormBrixx tank units wrapped inACOTex geotextile to form sedimenttunnel
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A
A
C
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C
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Plan view3
Installation guidanceACO can give guidance
with respect to the most suitablemethods of installation for the ACOStormBrixx range. ACO StormBrixxshould be installed using acceptablelevels of workmanship and according to the National Code of Practice (UK: BS 8000: Part 14:1989).
Detailed installation statements andmethodologies will vary for all sites as each will have different aspectsdeserving particular consideration,consequently the relevant approvalsshould be sought from the consultingengineer and/or the installer.
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ACO STORMBRIXX INFILTRATION SYSTEM
Inlet
Inlet
ACO StormBrixx soakawaysystem with sediment forebayand integral catchpit
This soakaway layout is designed tominimise the potential for silt andsediment to blind the base of thesoakaway by ensuring larger debris andsilt is retained in an area that allows forits removal and cleaning of the system.
The sediment forebay and catch pit iscreated by first installing the catchpit andaccess chamber and connecting the inletpipe. The lower part of the accesschamber should not have any panelsremoved so that it forms a catchpit, asecond access unit is place on top withthe base and three panels removed andthen connected to the inlet pipe.
Place all units for the lower layer and uselayer connectors to connect the accesschamber to the main structure. Once thishas been completed it will be necessaryto construct the sediment forebay to thedesired size and place this around theupper level of the access chamber. Thewhole of this construction requires sidepanels and to be completely enveloped inACOTex non-woven geotextile.
After this has been completed theremaining units can be placed and thewhole system wrapped in geotextilematerial.
The integral catchpit and accesschamber allows for the removal ofsediment from one central point.
Inspection points can be located at eachcorner of the tank as required, and canbe used to show the footprint of thesystem after installation. The inspectionpoints allow the extremities and all levelsof the system to be inspected if required.
A
D
2 2
3 3
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B D
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Plan view
Section 1-1
Section 2-2
Section 3-3
Individual ACO StormBrixx tank unit
ACO StormBrixx access chamber
ACO StormBrixx inspection point withductile iron cover and frame
ACO StormBrixx tank units completewith side panels wrapped in ACOTexgeotextile to form sediment forebay.
Perimeter of ACO StormBrixxinfiltration system complete with sidepanels, completely enveloped withACOTex non-woven geotextile.
ACO StormBrixx inspection point withextension raising piece and ductile ironcover and frame
ACO StormBrixx access chamber with a Ø375mm cut to 3 sides of thechamber module to enable access tothe system
ACO StormBrixx access chamber silt trap
H
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A
An electronic version of theACO StormBrixx installationdetail is available to downloadfrom the ACO website. Visit www.aco.co.uk.
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Guide to installing an ACO StormBrixx attenuation system
ACO StormBrixx
General advice
If the ACO StormBrixx system is to belocated in areas of high groundwatertable, contaminated land, close proximityto buildings, or where the risk ofcontamination from surface water is high,ACO strongly recommend that the liningsystem is installed by a competent,qualified geomembrane lining contractor.Please consult the ACO WaterManagement Design Services Team forfurther advice.
Installation guidance
ACO can give guidance with respect tothe most suitable methods of installationfor the ACO StormBrixx range. ACOStormBrixx should be installed usingacceptable levels of workmanship andaccording to the National Code ofPractice (BS 8000-14:1989).
Detailed installation statements andmethodologies will vary for all sites aseach will have different aspects deservingparticular consideration, consequently therelevant approvals should be sought fromthe consulting engineer and/or the installer.
Step 1
Excavate the pipe trench and lay the inletpipe to the required fall and invert level,install silt traps in appropriate locations inthe pipe run or use the ACO StormBrixxaccess chamber.
Step 2
Excavate the hole or trench to therequired dimensions to receive the ACOStormBrixx tanks, and any externalinspection chamber(s) and/or silt trap(s).
Step 3
Ensure that the base plan dimensions ofthe hole allow 300mm working space onall sides for the site operatives tomanoeuvre the ACO StormBrixx units,geotextile and geomembrane intoposition. Ideally mark out the plan areawith spray paint or chalk line.
Step 4
Ensure that the base of the excavation issmooth and level and capable ofwithstanding the design loads, batter backthe sides of the excavation to a safe angle,and ensure that safe access is provided forthe site operatives. The excavation shouldbe carried out in accordance with BS 6031:2009 with particular attentionpaid to safety procedures.
Step 5
Ensure that ground bearing capacity atformation level is adequate for designloads. Remove any soft spots from theexcavation and replace with compactedgranular material.
Step 6
Lay 100mm compacted Type 1 or 2bedding layer to the base of theexcavation and level. It is essential thatthe bedding layer is correctly levelled andsmoothed, and that the base groundbearing capacity is adequate for designloads.
Step 7
Lay the geotextile, to the specification onpage 16 and 17, over the Type 1 beddingand up the sides of the excavation withminimum 300mm overlap joints betweenstrips. Inspect geotextile for damage.
Step 8
Fabricate the geomembrane liner, bearingin mind the general advice above and thespecifications on page 16 and 17, andensure all joints or welds are tested. If indoubt please consult the ACO WaterManagement Design Services Team forfurther advice.
Step 9
Assemble the ACO StormBrixx modularunits to the plan size and unitconfiguration required and place on thegeomembrane. Ensure any loosecomplete units are fixed together usingthe ACO StormBrixx layer connector.
29
Step 10
If a sediment tunnel has been specified,lay the units with two side panels directlyinline with the inlet and outlet pipes andencapsulate in ACOTex geotextile. Placethe remainder of the ACO StormBrixxunits either side of the sediment tunnel.Where necessary, insert ACO StormBrixxconnectors between the layers of the ACOStormBrixx units. At the perimeter of thetank construction use side panels on allexternal boxes to create a rigid sidewall.
If a low flow drain down facility has beenspecified it will be necessary to install arow of ACO StormBrixx units in a trenchbelow the main attenuation volume inline with the inlet & outlet connections.This row needs to have side panels on allouter edges and to be enveloped with aprotection fleece and geomembrane onthree sides.
Step 11
Form hole(s) in the side panel of ACOStormBrixx unit using a hole saw andjigsaw to receive the inlet pipe (outlet/inspection/vent pipe if required). Inserttank connector together withgeomembrane top hat if required. Ensuretop covers are installed on the top layerof the system.
Step 12
Carefully cut geomembrane around pipeprotrusions and weld top hat to thegeomembrane tank liner. Then sealgeomembrane top hat to the pipe or tankconnector. Test all joints for leaks.
Step 13
Continue with the geomembraneencapsulation using welded or tapedjoints as appropriate. If protrusions existfor venting then repeat step 12.
Step 14
Check for leaks and test seals.
Step 15
Continue with the outer protectionencapsulation of the geomembrane andACO StormBrixx system. Fold the cornersof the protection fleece over-run at eachend of the attenuation tank.
Step 16
Complete the encapsulation by wrappingthe protection fleece horizontally roundthe tank and tape into position.
Step 17
Connect inlet/outlet/vent pipe and accesschamber using appropriate adaptors. Onlyone Ø110mm vent pipe is required per7500m! of the area to be drained.
Step 18
Backfill evenly around excavation usingType 1 or 2 sub-base or selected granularmaterial in layers of 150-300mm andcompact. The first 500mm of anyinstallation should be compacted by hand.
Step 19
Use a 100mm minimum coarse sandprotection layer over the top of the ACOStormBrixx units and geomembrane andthen backfill. There should be a minimum400mm backfill cover before compactionplant is used.
Step 20
The area should then be compacted usingsuitable compaction equipment inaccordance with the Manual of ContractDocuments for Highway Works (MCHW)volumes 1 & 2:
! Trafficked areas (eg restricted accesscar parks): Type 1 or 2 sub-basematerial compacted in 150 mmlayers in accordance with MCHWVolumes 1 & 2. Compaction plantover top of system should not exceed2300kg per metre width. Where theunits are to be installed beneath apaved area the pavement sub-basemay form part of the backfill materialprovided minimum cover depths aremaintained (refer to page 18).
! Landscaped and non-traffickedareas: selected as-dug material withsize of particles less than 40mmwithin 300mm of the top of theunits. Above this level selected as-dug material may be used. Placebackfill and compact in layers nogreater than 300mm. Compactionplant over top of system must not toexceed 2300kg per metre width.
30
ACO StormBrixx
General advice
The ACO StormBrixx units should beinstalled in accordance with theinstallation instructions and relevantlegislation. Special attention should bepaid to temporary work requirements inexcavations.
Installation guidance
ACO can give guidance with respect tothe most suitable methods of installationfor the ACO StormBrixx range. ACOStormBrixx should be installed usingacceptable levels of workmanship andaccording to the National Code ofPractice (BS 8000-14:1989).
Detailed installation statements andmethodologies will vary for all sites aseach will have different aspects deservingparticular consideration, consequently therelevant approvals should be sought fromthe consulting engineer and/or theinstaller.
Step 1
Follow steps 1-7 from the Guide toinstalling an ACO StormBrixx attenuationsystem (page 28) except lay 100mmcoarse sand bedding to the base of theexcavation and level instead of acompacted Type 1 or 2 bedding layer. For infiltration applications use coarsesand or class 6H selected granularmaterial in accordance with the Manualof Contract Documents for HighwayWorks (MCHW) Volumes 1 & 2. It isessential that the bedding layer iscorrectly levelled and smooth.
Step 8
Assemble the ACO StormBrixx modularunits to the plan size and unitconfiguration required and place on thegeotextile. Ensure any loose completeunits are fixed together using the ACOStormBrixx layer connector.
Step 9
Where a sediment forebay has beendetailed, form the forebay containmentstructure around the pipe inlet using sidepanels on the correct units to thedimensions specified. Encapsulate usingACOTex. Ensure top covers are installedon the top layer of the sediment forebay.
Step 10
Form the remainder of the ACOStormBrixx units to complete the overalldimensions specified.
Step 11
Where necessary insert ACO StormBrixxconnectors between layers of the ACOStormBrixx units. At the perimeter of thetank construction use side panels on allexternal boxes to create a rigid sidewall.Ensure top covers are installed on the toplayer of the system.
Step 12
Form hole(s) in the side panel of the ACOStormBrixx unit using a hole saw or jigsawto receive the inlet pipe (andoutlet/inspection/vent pipe if required).Insert tank connector and using ACOTexgeotextile form a wrap around apron of thetank connector spigot and secure usingtape or jubilee clip. Ensure a minimum50mm of spigot remains exposed.
Step 13
Continue with the geotextile encapsulationof the ACO StormBrixx system.
Step 14
Connect inlet/outlet/vent/inspection usingthe appropriate adaptors. Only one110mm vent pipe is required per7500m2 of area drained.
Guide to installing an ACO StormBrixx infiltration system
31
Step 15
Backfill evenly around excavation using 6N or 6P selected granular material inaccordance with MCHW volumes 1 & 2, inlayers of 150-300mm and compact. Thefirst 500mm of any installation should becompacted by hand.
Step 16
Lay a minimum 100mm coarse sandprotection layer over the top of the ACOStormBrixx units and geotextile and thenbackfill. There should be a minimum400mm backfill cover before compactionplant is used.
Step 17
The area should then be compacted usingsuitable compaction equipment inaccordance with Manual of ContractDocuments for Highway Works (MCHW)Volumes 1 & 2:
! Trafficked areas (e.g. restrictedaccess car parks): Type 1 or 2 sub-base material compacted in 150mmlayers in accordance with MCHWvolumes 1 & 2. Compaction plantover top of system should not exceed2300kg per metre width. Where theunits are to be installed beneath apaved area the pavement sub-basemay form part of the backfill materialprovided minimum cover depths aremaintained (refer to page 18).
! Landscaped and non-traffickedareas: selected as-dug material withsize of particles less than 40mmwithin 300mm of the top of theunits. Above this level selected as-dug material may be used. Placebackfill and compact in layers nogreater than 300mm. Compactionplant over top of system must notexceed 2300kg per metre width.
Step 18
The pavement construction orlandscaping is completed over the ACO StormBrixx system. Please readPost-installation protection of ACOStormBrixx below.
Post-installation protection of ACO StormBrixx
The ACO StormBrixx system is designed to withstand loadings from landscaped areas, car parks and service yards(subject to design criteria). However, after installation and backfilling, but prior to final surfacing, we recommend thatthe tank area is fenced off with high visibility fencing and traffic is prohibited from using the footprint area of the tank.
ACO StormBrixx is not designed to provide a load platform for construction traffic and should be treated accordingly.This action will protect the long term loading performance of the tank’s structure.
The client should provide sign posts indicating maximum loads allowable over the tank footprint, to ensure the longterm stability of the system is assured.
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ACO StormBrixx
Maintenance guidance
The definition of ownership and theresponsibility for maintenance ofconventional pipe drainage system isprovided in ‘Sewers for Adoption 7th
Edition’ and ‘Sewers for Scotland 2nd
Edition’. However guidance forSustainable Drainage Systems is a littleless obvious, particularly where it relatesto geocellular structures.
Therefore ACO would advise that therelevant potential adopting authorityshould be contacted and consulted beforesubmitting planning applications if theintention is to have the ACO StormBrixxsystem adopted.
It is important to note that failure tocontrol and remove sediment build-up inSUDS is the single largest cause ofsystem failure. The incorporation of asediment forebay in an ACO StormBrixxinfiltration system, or a sediment tunneland / or draindown feature in an ACOStormBrixx attenuation system, canensure the effective management of silt.
The open design of ACO StormBrixx allowsthe system to be inspected by remoteCCTV either through the inlet connection,access chambers, inspection points orpipes at the edges of the ACO StormBrixxsystem. This allows the system to beinspected for sediment build-up and for thecollected sediment to be removed from asoakaway or flushed through in the case ofan attenuation system.
In the event that a sediment forebay ortunnel has not been incorporated withinthe ACO StormBrixx system, it will benecessary to carry out the proceduresfollowing procedures:
Infiltration systems
In order to periodically check theeffectiveness of the ACO StormBrixxinfiltration system, a BRE 365 percolationtest can be carried out in the tank andcompared with the original data. If there isa significant decrease in the infiltrationrates, the infiltration tank should be filledvia the inspection chamber to the invertlevel of the inlet pipe. It should then beflushed through with water in order toremove sediment and unblind the geotextile.
Attenuation systems
In order to clean the ACO StormBrixxsystem, if a sediment draindown sump hasnot been incorporated, it will be necessaryto block the outflow control device, but notthe overflow pipe, before filling theattenuation tank to the invert level of thevent pipe. The tank should then be filledand flushed as above and the watereffluent removed and disposed of by apumped tanker.
If a draindown facility has been installed,simply lift the access chamber cover andusing a gully sucker remove all water inthe draindown sump and jet the sumpchannel as required to remove allsediment.
The frequency of the maintenanceprocedure for the tank will be determinedby the inspection regime, however CIRIAC697 recommends that a programme ofnot less than twice-yearly inspection iscarried out, and during the first year afterevery significant storm event.
In order to minimise silt build-up CIRIAC697 recommends the use ofpretreatment systems upstream of theattenuation device.
The Stormwater attenuation/infiltrationsystem shall be ACO StormBrixx by ACOTechnologies plc. The system shall havebeen tested in accordance with CIRIAC680 guidelines.
The ACO StormBrixx shall be 1.20m (L) x0.600m (W) x 0.610m (H) and crossand brick bonded throughout. Ultimatevertical strength should be 420 kN/m2
and ultimate lateral strength 90 kN/m2.
The units shall allow for free access forCCTV / jetting equipment and beconfigured to allow for the managementof silt utilising a sedimentforebay/sediment tunnel/low flow anddraindown facility*.
NBS Specification
ACO StormBrixx should be specified inNBS section R17:315. Assistance incompleting this clause can be found inthe ACO Technologies entry in NBS Plusor a model specification can bedownloaded from www.aco.co.uk. Forfurther assistance, please contact theACO Water Management Design ServicesTeam.
Maintenance and inspection guidance
Maintenance procedures
MODEL SPECIFICATION CLAUSE
As sediment has the potential to carry high levels of pollutant, it is important that anysediment removed from the system is disposed of by a licensed contractor and inaccordance with local regulations.
*delete as appropriate
33
Product Testing
Product performance tests carried out onthe ACO StormBrixx system have beenconducted using the methodsrecommended in CIRIA C680 “Structuraldesign of modular geocellular drainagetanks”. Data supplied can be supportedby qualified third party independentcertification.
Ultimate load bearing capacity has beenestablished under laboratory testingconditions during short and long termload testing. A summary of the structuralparameters of ACO StormBrixx can befound on page 18 – Designing an ACOStormBrixx system.
Please contact the ACO WaterManagement Design Services Team on01462 816666 for advice whendesigning ACO StormBrixx schemes.
Recycled content
ACO Technologies aim to incorporate asmuch recycled material or waste materialas is practicable in their manufacturedproducts without compromisingperformance. Typically PP materialscontain 50% plus recycled plastic andductile iron materials contain 40% to90% recycled iron.
The ACO StormBrixx products arethemselves intended for a long life withlow maintenance, to reduce the need torecycle, but when eventually they are nolonger needed, their materials can bereadily recycled with a very low risk ofpollution to the environment.
ACO Q-Ceptor
ACO Qmax® – New sizes available ACO MultiDrain™ MD ACO KerbDrain®
34
The point at which run-offenters the surface watermanagement system. Drainagechannels can be used
individually or in combination to ensureoptimal removal of all surface water.
With the most comprehensive range ofchannels available, ACO systems aremanufactured from a variety of materialsand are suitable for load bearing indomestic applications through the carpark, highway, dock and airportapplications.
Run-off that picks up surfacepollutants and silt will need tobe treated before discharge.
Oil separators such as ACO Q-Ceptor offer an effective solutionproviding full or bypassed treatment of oilpolluted surface water.
ACO’s sustainable water management system
ACO Q-Cell
To help architects, designers and contractors meet the legal requirements that nowtightly control the way surface water is managed, ACO has created its unique ‘SurfaceWater Management Cycle’ – Collect, Clean, Hold, Release – the four core processesrequired for the complete and sustainable management of surface water drainage.
Collect
Clean
ACO Q-Brake Vortex
ACO StormBrixx
35
Storage for controlled dischargeor infiltration into theimmediate environment is animportant aspect of managing
surface water in the SUDS approach.ACO StormBrixx provides an ideal methodof delivering effective management ofsurface water where swales and pondsare not possible.
Controlling the release of cleansurface water into the naturalenvironment requiresappropriate upstream controls
which culminate in an appropriatelymanaged flow. This can be achieved via aflow controller such as ACO Q-BrakeVortex or through a soakaway.
Hold
Release
ACO Water Management: Civils + Infrastructure
A division of ACO Technologies plcACO Business Park,Hitchin Road,Shefford,Bedfordshire SG17 5TE
Tel: 01462 816666Fax: 01462 815895
e-mail Sales: [email protected] Technical: [email protected]
website: www.aco.co.uk
The ACO Group: A strong family you can depend on.
© May 2012 ACO Technologies plc. All reasonable care has been taken in compiling the information in this document. All recommendations and suggestions onthe use of ACO products are made without guarantee since the conditions of use are beyond the control of the Company. It is the customer's responsibility toensure that each product is fit for its intended purpose, and that the actual conditions of use are suitable. This brochure and any advice is provided by ACOTechnologies plc (the Company) free of charge and accordingly on terms that no liability including liability for negligence will attach to the Company or its servantsor agents arising out of or in connection with or in relation to this brochure or any such advice. Any goods supplied by the Company will be supplied solely upon itsstandard conditions of sale, copies of which are available on request. The Company's policy of continuous product development and improvement rendersspecifications liable to modification. Information provided in this brochure is therefore subject to change without prior notification.
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