TECHNICAL 35
Why should I fit an extra stopcock if my Geyser Valve already has one ?
By Patrick Gordon of Calafrica ( technical @ calafrica . co . za )
Before we discuss this , we need to look at what the law requires .
SANS 10252-1:2018 Edition 3.2 specific isolating valve as when any replacement of the valve needs to take place , you still need a separate valve to isolate the water .
6.1.3 Isolating valves 6.1.3.1 Unless otherwise required , or provided that 6.1.3.2 does not apply , a specific isolating valve shall be provided c ) where a pipe enters any building or any portion of a building in separate occupation ,
In this type of installation , it makes sense to fit a Pressure valve that does not have an integral isolator as they are less expensive , and an isolating valve still needs to be fitted in any case .
Here SANS requires us to install a specific isolating valve where the pipe enters the building , or in the case of apartments etc . that have multiple dwellings that make up a building , every place that there is a water supply that enters the building . There is one exception to this rule and that is contained in 6.1.3.2 .
6.1.3.2 Notwithstanding the provisions of 6.1.3.1 , an isolating valve shall not be provided between any pressure reducing valve and a water heater if such a pressure reducing valve incorporates an expansion relief device or vacuum relief device intended to protect such water heater .
Here it tells us that if there is a Pressure Reducing valve with an integral expansion valve , the specific isolating valve must be before the pressure valve .
What does this mean ? If you have a balanced pressure installation , with the valve positioned outside the dwelling , you are not allowed to fit any appurtenance that can isolate the Hot Water Cylinder from the route to expand . It has become common practise to fit an isolating valve near the HWC so that the dwelling can still be supplied with water if the HWC should fail . This practise can continue with the provisor that a separate expansion valve is fitted between the isolating valve and the HWC . Thus , still allowing for any expansion to be effectively vented .
The integral isolating valve that is incorporated in some of the Pressure Control Valves cannot be classified as a
Considering these points it is obvious that we must re-look at the way that we currently do installations so that we can stay in line with what is required by law and also to deliver the user comfort that our customers are used to .
For any further information on this topic please contact the writer : PA Gordon patrick . gordon @ calafrica . co . za PA
“ The specific isolating valve must be before the pressure valve .”
May 2022 Volume 28 I Number 3 www . plumbingafrica . co . za