How Often Do Domestic Sprinklers Need Testing?
Over the years, we have installed literally ‘hundreds’ of domestic fire sprinkler systems and yet the take-up rate for a maintenance contract which includes an annual test is extremely low.
How important is a yearly test for a mains system?
A domestic sprinkler system connected to a mains water supply needs very little maintenance however there are a couple of checks which are essential. In fact the typical type of concealed fire sprinkler head which is the most frequently installed sprinkler head in domestic situations requires nothing more than a visual inspection to ensure that the cover plate is free to release in the event of a fire. These cover plates are often painted when the ceiling is decorated which can delay the activation of the domestic sprinkler.
Another consideration is whether or not the audible alarm associated with the system is functioning correctly.
The most important consideration however, is to verify that the pressure and flow available from the town main is still sufficient to ensure the system tackles a fire effectively in the event of the domestic fire sprinkler activating.
The pressure gauge never lies! – or does it?
Every domestic fire protection system incorporates a pressure gauge. However, you should never solely rely on the system pressure gauge reading to verify that the system is functioning correctly for the following reason:
Every system also incorporates a non return valve which allows water to pass from the town main into the sprinkler pipe work. This allows the pressure within the system, to build up to that of the town main when it is initially filled. The problem is that should the pressure in the town main be reduced or worse still a valve is closed by mistake up stream, the pressure on the other side of the non-return valve (i.e. in the sprinkler system pipe work) will remain unchanged because the non return valve prevents any flow from the system back into the town mains ( or pressure equalisation)
The only way to verify that there are not any hydraulic restrictions in the supply to the system is to carry out a dynamic pressure and flow test
Who should carry out yearly testing?
Some private individuals and organisations which have had home fire sprinkler systems installed in their properties rely on a fire alarm company to carry out the yearly testing even though BS9251 states that testing should be carried out by suitably trained staff
The only way to test a domestic sprinkler system properly is to know the dynamic pressure and flow requirements which the system designer had calculated at the time of installation and then to drain a very large quantity of water from the system noting the flow rate ensuring that the dynamic pressure reading at this flow matches the system requirement. This method of testing is called equivalence testing and utilises skills and equipment which the average fire alarm testing company would not possess.