CIRIA C680 and SuDS Compliance Evidence Checklist

The evidence an LLFA or SuDS Approving Body expects behind a geocellular attenuation tank. Tick what your shortlisted supplier can actually produce — a strong scheme answers every row without hesitation.

Structural test evidence

Third-party load test report (with report number) Independent lab, e.g. ISO 17025 — not a self-declared datasheet figure

Test method named (CIRIA C680-2008 vertical load) A tonne number with no method is unbuildable

Per-grade load classes (kN/m²), not one headline figure Match the crate to the duty; e.g. SG-E20 200 to SG-H60 600 kN/m²

Current design framework

Structural design to CIRIA C737 (supersedes C680) C680 is a 2008 document; C737 is the current standard

Product standard BS EN 17152-1 Current EN spec for PP/PVC-U stormwater boxes

Void ratio and design life stated with basis e.g. 95% void, 50-year design life as a system condition

Scheme and submission

Discharge rate and storage volume with climate allowance The hydraulic case an LLFA/SAB signs off, per CIRIA C753

Maintenance and silt-management plan + inspection access Service life depends on desilting, not just the plastic

Cover depth engineered to load and ground (not a default) Designed to the crate grade and wheel loads, not a fixed number

Tick the evidence your supplier can produce

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