If your commercial premises are sprinkler-protected, quarterly flow switch testing is a mandatory requirement under BS EN12845. Marlowe Fire & Security offer a nationwide service to attend and carry out routine fire sprinkler flow switch testing.

What is a flow switch?

A flow switch is used to monitor the flow of different types of substances – usually air or water. It senses different pressure generated from different flows.

A flow switch, in the case of a sprinkler system, will send a signal back to the main building fire alarm to indicate the system is working and there is the correct flow of water around the system. If a flow switch is not working properly, adjustments might need to be made. The flow switch should be replaced every five years or 100,000 cycles, whichever comes first.

A flow switch is an electro-mechanical device that is the interface between a building’s fire suppression or sprinkler system and the fire alarm system. Flow switches don’t turn on or off the delivery of water, they just activate the fire alarm when they detect that water is moving in the system, such as when a sprinkler head has been activated.

How does a flow switch test work?

All flow switches should be tested in accordance with TB203.3.2 as part of a mandatory quarterly service routine. For the test to be valid, sufficient water must pass the flow switch to activate it (equal to one sprinkler head in operation). Prior to the test, the pressure on both sides of the flow switch will be equal, maintaining an equilibrium with no water flowing.

During the test, water is discharged from the down-stream end of the pipe causing a drop in pressure (or in the case of a looped system, pumped around a closed circuit) which causes the flow switch to operate.

When should I test my flow switch?

Sprinkler flow switches are usually tested before a shopping centre opens or work begins on a factory floor so that there’s minimum disruption for your customers or your workforce. Marlowe Fire & Security engineers are used to working at unusual hours or before premises open and, once they are on site, they are available to undertake other mechanical, system or electrical work.

There are a number of advantages to this way of working. Cutting down on numerous trips by different engineers is cost effective and Marlowe Fire & Security is able to pass on savings to customers without compromising safety standards. It is also more environmentally friendly which is an important consideration for many organisations.