8.9 Drainage Materials

All materials must be compliant with the Specification for Highways Works and be British Board of Agreement (BBA), Highways Authority Product Approval Scheme (HAPAS) marked.

Plastic products must be avoided where possible. For example, products such as Hydro Rock can be used instead of plastic crates for attenuation storage.

Design drawings submitted as part of the technical approval process shall contain construction details for all infrastructure including:

• Layout drawings with manholes and pipe runs clearly referenced;
• Longitudinal sections of all main runs;
• Full pipe and manhole schedules, including diameters, material, depths, load class, etc;
• Details of gullies, channels, etc;
• Construction details, where standard details are not used.