Design

Introduction

Gravity is relied upon to move waste water from the appliance (basin etc.) to the drain. Waste pipes should therefore be installed to a slight fall; at least 20mm in every metre, to make sure the water runs freely away.

32mm pipe and fittings are used for basins and small sinks.

40mm pipe and fittings are used for kitchen sinks, baths, showers and washing machines.

Waste branches are often used to connect a bath/shower and basin to the soil stack. It is important that a 45° tee is used to ensure the basin discharge is swept in the direction of flow towards the stack.