
BS 9251:2014 is the British safety standard for fire systems installed in domestic and residential occupancies. It gives recommendations for the design, installation, maintenance and testing of fire sprinkler systems, which also apply to any additions, extensions, repairs, or other modifications that might be made to the system over time.
These regulations are set to be updated in October. The new recommendations – BS 9251:2020 – will lay out requirements for the monitoring of specific elements within each fire sprinkler system.
Monitoring BS 9251 fire sprinklers
Fire sprinkler systems sit dormant until they are needed, in the event of a fire. There are critical elements of the sprinkler system that could affect how the sprinklers operate. Without adequate monitoring of these elements, you may not realise if any have been compromised. This could affect the efficacy of your sprinklers.
The current regulations
We’ll use isolation valves as an example here. Under the Current BS 9251:2014 regulations, isolation valves should be lockable and left locked in the open position. However, once the system has been commissioned or serviced, there is no way of knowing if that lock has been removed or the isolation valve has been closed.
There may come a time when the water supply to the sprinklers needs to be isolated for maintenance (perhaps while refurbishment works are being undertaken or during an issue with the water supply). Should the isolation valve not be returned to the locked open position after maintenance work has been completed, the sprinklers will not operate when needed. The valve could be closed and the occupant would be none the wiser until it was too late. That’s why the new regulations state that isolation valves be monitored constantly.
What’s changing? The new regulations explained
The revised BS 9251:2020 regulations are set to come into force in October. They will require all isolation valves to be electronically monitored to ensure they are in the open position.
Sprinklers do more than just detect a fire
Sprinkler monitoring is the continuous supervision of critical elements of the system. These elements are as follows:
- Isolation valves – to ensure the valve is in the fully open position
- Tank level switches – to raise an alarm in the event that the required stored capacity falls below 90%
- Booster sets – to raise an alarm in the event of a fault or loss of power
A dedicated sprinkler monitoring system should be in place to monitor all of these points and raise an alarm in the event of any failures.
Isolation valves explained
In accordance with BS 9251, there are two main types of isolation valves in domestic and residential sprinkler systems. In each zone, most commonly one per floor, there is a residential riser valve set consisting of a pressure gauge, isolation valve, flow switch and test point. The second type of isolation valve is a standard lever valve designed to isolate supply, most commonly used in BS 9251 sprinkler systems to isolate an individual apartment.
To monitor the isolation valve, a switch is fitted that makes sure the valve remains in the fully open position. If the isolation valve begins to shut, the switch sends a signal to the monitoring device to warn that the isolation valve is not in the fully open position.

This would replace the standard valve sets and enable them to be connected to a monitoring system.
Tank level switches explained
A level switch in a tank traditionally has two main functions, high or low level. High-level tank switches raise a warning if the ball valve has failed and too much water is in the tank causing it to overflow.
Low-level tank switches are installed near to the point where the tank runs out of water and stop the booster pump from attempting to run without adequate water supply. This prevents damage to the pump.
In the context of sprinkler monitoring, we need to know when the tank falls below 90% of its required capacity – it’s too late to notify when the tank is empty. Notifying when the tank falls below 90% capacity allows time for action to be taken before it’s too late.
Booster sets explained
When a town’s main supply provides insufficient water pressure and flow, a booster pump is fitted to provide sufficient supply. This can be either directly off the mains or using a stored water supply. The pump will be fitted with an automatic test facility that has a fault output. This output can be connected to the monitoring system which will raise an alarm in the event of a pump failure. An alarm will also be raised if power to the pump is lost.
Not in the building but want to know if the sprinklers have activated?
The flow switches on a sprinkler system normally serve the purpose of initiating the emergency procedures, such as raising an alarm on the fire alarm panel (however, this is all dependent on the fire strategy). Connection of the flow switch to an appropriate fire alarm should always be done in accordance with the fire strategy for the building.
Monitoring systems can also be used to monitor flow switches, so that the system is aware when the sprinklers are active. This can be extremely useful to building owners in certain circumstances.
For example, in assisted living accommodation, where the occupants may be hard of hearing or visually impaired, it would be beneficial for the building manager to be made aware of a sprinkler system activation. That way, they can check on the occupants and raise the emergency protocol if necessary.
Confused about the BS 9251 fire sprinkler system regulation changes?
If you need help understanding the regulation changes and fitting a monitoring system to your sprinklers, the experts at South Coast Fire Sprinklers are here to help. We will assist with the design of your monitoring system, selecting compatible products and providing full wiring details. If you provide a copy of the fire strategy report, we can also advise on the correct configuration of the alarm strategy and integrate the monitoring system accordingly.
For more information, please don’t hesitate to get in touch with us today on 01202 731111.