34
TECHNICAL
Do I need a grease trap or an oil separator?
By
Patrick Gordon, technical manager, Splashworks
This is something that we often omit from our installations – most homes do not have one and can go for years without seeing the consequences of not having one.
We don’ t think about all the natural oils and fats that get washed from our bodies every time that we bath or shower. These get washed down the drain and as the liquid in the drain cools, these will get deposited on the sides of the drain pipes and will eventually cause enough of an obstruction to catch hair and other solids that are carried down the system with daily use.
In most installations this would not cause enough of a problem to warrant the installation of a fat trap or an oil separator( light liquid interceptors).
Where we do have more of a problem is in the kitchen drainage installation. Our cooking produces a lot more fats that gets washed down the drain when we wash the dishes. This normally is accompanied by a fair amount of vegetable and other protein matter.
For this type of installation a grease trap gully will be installed where the waste pipes from the kitchen discharge outside. The unit has three sections:
• One, where the waste water enters the system,
• Two, where the basket strainer can be removed for cleaning purposes, and
• Three a port that is connected to a rodding eye should the drain get blocked.
The basket strainer would traditionally be made from galvanised sheeting as rust is not a big factor. More recently, there are also PVC units available.
The National Building Regulations do not call for grease traps to be installed in domestic installations except were septic tanks or conservancy tanks are part of the installation.
All images sourced from National Building Regulations and Pollution Solution Africa
More sophisticated and complex grease traps are, however, required by law for all restaurants and commercial kitchens. These is also not a one-size-fits-all type of unit – a specialised professional needs to calculate and design a customised specification for each installation.
www. plumbingafrica. co. za @ plumbingonline @ plumbingonline @ PlumbingAfricaOnline November 2026 Volume 32 I Number 09