The LWF Blog

Fire Safety for Healthcare Premises – Power Supplies for Fire Alarm Systems – Part 140

August 10, 2020 2:06 pm

In LWF’s blog series for healthcare professionals, our aim is to give information on best practice of fire safety in hospitals and other healthcare premises. In part 139, LWF considered the impact of electromagnetic interference on fire alarm systems. In part 140, we discuss power supplies to the fire detection and alarm system in a healthcare environment.

It is highly important that a consistent power supply is available to the fire detection and alarm system in a healthcare building. The fire alarm system must be able to detect and alert to the presence of a fire at all times, even when conditions are sub-optimal. The main and backup power supplies should be of a high standard and the reliability of both supplies must be absolute.

The fire detection and alarm system should be mains supplied and derived from the healthcare premises essential services supply, which has an automatically started standby generator as backup.

The number of isolating devices between the incoming supply and the fire alarm control must be kept to the minimum practicable.

From the point at which supply is provided with the dedicated isolating-protective device, as described in BS 5839-1, the circuit must be treated as a Category 3 circuit, as defined in BS 7671 and the circuit should be segregated from other circuits.

Any and all cables associated with the fire alarm system, including power cables, should be rated “enhanced” fire resistance, as described in BS 5839-1, Section 2, Clause 26.2 and recommended in part (c) (3) of that clause. The mechanical protection provided for cables must comply with recommendations as contained in Section 2, Clause 26.

Standby battery supplies for any part of the fire detection and fire alarm system in a healthcare building must be capable of maintaining the system in normal operation for a minimum of 24 hours, after which time, it must retain sufficient capacity to operate all sounders in evacuation mode for at least 30 minutes.

In Part 141, LWF will look at the system technology available for healthcare venues. In the meantime, if you have any questions about this blog, or wish to discuss your own project with one of our fire engineers, please contact us.

Lawrence Webster Forrest has been working with their clients for over 25 years to produce innovative and exciting building projects. If you would like further information on how LWF and fire strategies could assist you, please contact LWF on freephone 0800 410 1130.

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.

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