Case studies·7 min read·
Stormwater attenuation crates from recycled PolyAl: a circular SuDS option
Modular stormwater storage crates moulded from PolyAl pellets are entering UK and EU SuDS specifications.
Sustainable Drainage Systems (SuDS) increasingly require modular underground storage crates to manage stormwater. The market is dominated by virgin polypropylene crates from a handful of manufacturers. PolyAl is now an emerging alternative.
Why PolyAl works
- Compressive strength > 400 kN/m² (sufficient for HGV traffic loading at depth ≥ 0.6 m cover)
- 100+ years buried-service expectancy (no UV exposure underground)
- Hydrolysis-stable in groundwater
- Reduced carbon footprint vs virgin PP (savings ~1.0–1.4 t CO₂e per tonne of crate)
Typical crate spec
- 1200×600×400 mm modular cube
- 25 kg per crate
- 95 % void ratio (storage capacity 273 L per crate)
- Connectable in arrays of any size
- Inspection port compatible
Standards
- BS 8582 (UK SuDS code)
- DIN 4262 indicative for buried plastic structures
- Hauraton, Wavin, Polypipe and others have published methodologies adaptable to PolyAl crates
Cost
PolyAl crates in the UK and Spain currently price 10–15 % below virgin PP equivalents — a rare combination of lower carbon AND lower cost.
Specifying for tender
Key clauses to include:
- Recycled content > 90 % post-consumer (UNE 53925:2026 reference)
- Per-batch CoA available
- Compatible with standard inspection cameras
- 50-year design life
For designers reaching for SuDS modules with a credible recycled-content story, PolyAl is now a real choice.