The LWF Blog

Fire Safety for Facilities Management Personnel – Sprinkler System Components – Part 233

January 3, 2024 12:11 pm

Lawrence Webster Forrest (LWF) is a specialist fire engineering and fire risk management consultancy whose aim is to give information on best practice in fire safety for facilities management personnel through this blog series. In part 232, LWF began to examine the components of a sprinkler installation. In part 233, we continue to discuss sprinkler system installations and components.

The main valve set for a sprinkler system includes an installation stop valve and an alarm valve. When the sprinkler is activated and the head opens, water flows into the installation and the alarm valve allows a small amount of water to flow down small bore pipework, terminating in a water-driven gong. This is normally located outside the building and is to provide a warning.

Additionally, it is possible to install a pressure switch to the pipework which allows the sprinkler system to connect with a fire alarm system. This allows the fire alarm system to operate when a sprinkler head opens.

As an alternative, flow switches can be fitted to installation pipework to achieve the same result or to provide accurate information as to the location of the fire.

In a large, multi-occupancy building, such as a shopping centre, a sprinkler installation may serve various occupancies. A pressure switch in the alarm line pipework would indicate that the installation is discharging water, while a flow switch in the pipework to each area (or shop in the case of a shopping centre), confirms in which location the discharge is occurring.

In the case of a pre-action sprinkler installation, the dry pipework is charged with water when the automatic fire detector activates. It may also operate as a conventional dry installation, in that he pipework will become charged with water even if the detection system fails to operate. More commonly, however, the system can be configured so that the pipework becomes charged only when a fire detector activates.

A pre-action valve set required is costly and an interface with an automatic fire detection installation reduces the inherent reliability of a wet sprinkler installation. Such systems tend only to be used where there is a concern of water damage as a result of accidental damage to sprinkler heads, or where there may be a need to speed up the operation of a dry system.

Recommendations for pre-action sprinkler systems interfacing with fire detection and alarm systems can be found in BS 7273-3

In part 234 of this series, LWF will look at sprinkler installation design principles. In the meantime, if you have any queries about your own facilities or wish to discuss this blog series, please contact LWF on freephone 0800 410 1130.

Lawrence Webster Forrest is a fire engineering consultancy based in Surrey with over 35 years’ experience, which provides a wide range of consultancy services to professionals involved in the design, development and construction and operation of buildings.

 

While care has been taken to ensure that information contained in LWF’s publications is true and correct at the time of publication, changes in circumstances after the time of publication may impact on the accuracy of this information.