Drainage – Doing It by the Book

Drainage – doing it by the Book – By Ilana Koegelenberg; Staff Writer at RACA Journal.

Most structures, both residential and commercial, tend to generate a lot of waste. It is important that there are regulations in place to ensure it is properly disposed of in order to promote both personal and environmental health.

The National Building Regulations (SANS 10400) has a lot to say about drainage and how to do it right, in part P, the specifically dedicated section. We take a look at section 4 of this standard to investigate the requirements for drainage as per SANS 10400-P. Note that this article merely highlights certain sections and extracts of the standard, not the standard as a whole.

Materials, pipes, fittings, and joints
In a drainage installation, joints used between pipes and fittings must be compatible with the materials these are made of. It must remain watertight under normal conditions and be able to withstand an internal water pressure of 50kPa and an external water pressure of 30kPa without leaking.

Sanitary fixtures
Sanitary fixtures must be made of water-resistant, non-corrosive materials, with a smooth and readily cleanable surface. This fixture must be fitted so it discharges through a trap into a soil/ waste pipe. It’s prescribed that the water supply outlet to waste fixtures has to be situated at least 20mm above the flood-level rim of this fixture.

When it comes to electrical sanitary fixtures, all washing machines (dish and clothes) that are permanently connected to a drainage installation, must discharge through a trap into a waste pipe. The drainage installation can’t include any disposal unit with a power capacity greater than 15A/ 550W, unless this unit is registered and installed in compliance with the relevant requirements.

Any waste disposal system, other than domestic, has to be connected to a suitably sized grease trap before it connects to the drain. Continue reading…