Attenuation Grade & Height Selector

Pick the surface above the tank and the depth you have. The tool returns the StormGrid grade and height to price against, plus the module count for your storage target.

What sits above the tank?

Choose by the heaviest vehicle that will ever cross it, not the typical one.

How much excavation depth can you take?

H400 modules are 400 mm tall, H500 are 500 mm.

Target storage volume (m³)

The volume your drainage engineer has calculated from the permitted discharge rate.

SG-M40 · H500

40 t/m²Nominal load grade

237.5 LStorage per module

4.2Modules per m³

1,053Modules for your volume

Recycled PPMaterial class

Scope of this tool. This is a product pre-selection aid, not a structural design method. Site-specific structural adequacy — cover depth, surround, groundwater and traffic loading — is determined by a CIRIA C737-consistent design carried out by the project’s drainage or civil engineer. Module counts are geometric and exclude wastage, cutting and site-specific layout losses.

Send this configuration for a quote and layout drawing