When designing and installing clay drainage systems, sticking to the Building Regulations and relevant standards is critical to ensure safety, functionality, and compliance. The key regulations and standards include:

BS EN 752:2017 (drain and sewer systems outside buildings)

BS EN 1295-1:1997 (structural design of buried pipelines). These standards provide guidelines on the layout, gradient, and structural requirements necessary for successful clay drainage systems.

Design and Layout

The layout of a clay drainage system should minimise excavation by utilising the natural slopes of the site to achieve the required gradients. Changes in direction and gradient should be kept to a minimum, and access points must be provided at strategic locations for maintenance, such as rodding and inspection. Compliance with Approved Document H of the Building Regulations is essential for determining access fitting locations and ensuring that the system allows for proper cleaning and maintenance without entering the building.

Installation Standards

The installation of clay pipes follows rigorous protocols, including trench preparation, jointing, and backfilling. It’s crucial to ensure the pipes are adequately supported, particularly by trimming trench bottoms or using appropriate bedding materials like recycled aggregates. Jointing should be done with care, starting at the downstream end, ensuring the seals are clean, and applying the correct lubrication to achieve a tight fit. Testing, such as air tests, should be performed before backfilling to ensure joints are secure.

Backfilling is typically carried out in compacted layers to protect the pipes and ensure long-term stability. For deeper installations, mechanical compaction equipment may be used once a sufficient cover of material is placed over the pipes.

Compliance with UK Standards

Clay drainage systems must comply not only with Building Regulations but also with additional UK standards such as Water UK Sewers for Adoption and Department for Transport requirements for public infrastructure projects. These standards ensure that clay pipes meet the structural and hydraulic performance criteria needed for both residential and industrial drainage systems.

By adhering to these regulations and installation guidelines, clay drainage systems can provide reliable, long-term performance with a life expectancy of over 100 years.

For more details, you can explore further on the CPDA website.