Polypipe PSM1A Polystorm-R Soakaway Crate & Attenuation Cell (61 Tonne)

This Polypipe PSM1A soakaway crate, also known as Polystorm-R is designed for not only soakaway applications but also for attenuation cells. They can be used in non-trafficked and trafficked areas, ideal for housing, car parks, driveways, commercial and infrastructure projects. The PSM1A is a well-established product in the underground drainage and SUDS industry. It is very easy to install this modular cell system, making it one of the most popular cellular soakaway crate options in the UK. Each PSM1A crate unit includes 4 clips and 2 shear connectors.

Polystorm crates can be quickly combined together to create a robust flexible tank under hard surfaces, allowing you to store water channelled from surface drains and building guttering with an interlocking mechanism. PSM1A crates offer a bespoke approach to subsurface water storage, giving contractors and specifiers the opportunity to create unique designs to suit the exact demands of their development or project.

For a soakaway system, it is highly recommended to install your soakaway crates with a non-woven geotextile or protection fleece. This ensures that you protect the crates from being clogged up by debris, yet still allowing water to pass through. If you are installing an attenuation tank system, in addition to the geotextile you will need to use a geomembrane to ensure the water is retained within the attenuation cells.

Key Benefits of the PSM1A Polystorm-R Crate:

• Suitable for both attenuation and soakaway systems


• 100% Recyclable and environmentally friendly, made from specially selected and controlled recycled materials


• BBA approved and has undergone stringent testing to ensure product performance


• Compressive strength of 61 tonnes/m2, designed for trafficked and loaded applications


• Flexibility of shape so you can create narrow strips, shallow excavation systems or use in restricted areas


• Lightweight provides excellent health & safety and installation benefits for site


• 3D flow throughout the structure and has a integrated inlet and outlet

ELEMENT	VALUE
PHYSICAL PROPERTIES
Dimensions L x W x D	1000mm x 500mm x 400mm
Total Volume	0.2m3 (5 Crates = 1m3)
Unit Weight	9kg
Unit Storage Volume	0.19m3 (190 litres)
Void Ratio	95%
SHORT TERM COMPRESSIVE STRENGTH
Vertical	Maximum 610 kN/m2 *
Lateral	Maximum 63 kN/m2 *
SHORT TERM DEFLECTION
Vertical	60 kN/m2 per mm
Lateral	4.4 kN/m2 per mm

* Compressive strength at yield, maximum recommended value for design purposes.

Soakaway crate systems enable the surface water to run-off, accumulating in an below ground tank entering the surrounding land through a permeable geotextile or protection fleece. We advise that your groundworker or contractor carries out a percolation test on your soil and its conditions, to correctly calculate the number of crates for your project. As a typical guide, providing your soil type is not clay or heavy, you can roughly estimate the size of your soakaway using a ratio of 1 crate per 10m2 of surface area that you are draining. However we do recommend the correct tests are undertaken prior to designing your soakaway crate system. It you find that your ground conditions are not suitable for a soakaway system, then a holding tank or attenuation system will be required which typically discharges to an existing drain or water course by either gravity or via pumping at a pre-determined rate.

Sustainable Drainage Systems, also referred to as Sustainable Urban Drainage Systems or SuDS, have become a vital asset to prevent urban flooding for various developments across the UK, no matter how big or small. PSM1A crates can be utilised in multiple SuDS techniques including sports pitches, attenuation storage tanks, bioretention & rain gardens, infiltration, swales, filter drains, ponds & wetlands and detention basins. Crates systems are a perfect stormwater management solution by preventing flooding during heavy rainfall periods by holding back excess water and then gently releasing the water back into the environment. By gently releasing, this prevents local watercourses and sewer networks become overflowed which results in floods being prevented.

Manufactured by Polypipe, one of Europe’s largest and innovation manufacturers of drainage crates provides the installer with a reliable crate that will perform. They are passionate about being able to deliver small and large scale flood alleviation solutions to the traditional civils and infrastructure sectors. These PSM1A crates are a fantastic alternative to the Aquacell soakaway crates.

BBA approved. Recommended minimum cover level depth required is 0.5m for pedestrian areas. In accordance with the recommended methodology and factors of safety given in Structural Design of Modular Geocellular Drainage Tanks, CIRIA C680 (2008), prior to the commencement of construction projects. The installer of a proposed geocellular crate structure should ensure that an appropriate design check has been carried out. For areas with weak clay soil conditions, the maximum burial depth is reduced. For further product information, please refer to the product datasheet on this page.