The LWF Blog
Fire Safety Engineering for Design – Fire Detection & Alarm Systems – Part 133May 22, 2023 11:12 am
LWF’s Fire Safety Engineering blog series is written for Architects, building designers and others in the construction industry to highlight and promote discussion on all topics around fire engineering. In part 132, LWF looked at the necessity for fire alarm and detection systems in different types of buildings and occupancies. In part 133, we continue to discuss the use of fire detection and fire alarm systems.
In certain circumstances, a fire detection and alarm system may be required in order to make other fire protection systems work as intended. For example, a mechanical smoke ventilation system may be required and will rely on the smoke detectors of the fire alarm system. The same principle may apply to other fire protection measures such as automatic fire and smoke dampers, pre-action sprinkler systems, automatic fire and smoke curtains and devices to release fire doors.
BS 5839 Parts 1, 6 and 8 mention the use of fire alarm systems to work alongside other fire protection systems, but do not apply to those systems. NFPA 72 contains some reference to fire safety function control. Section 6.15 talks about the control of other life safety systems by the fire alarm control panel.
If a fire alarm system is required, the choice between manual and automatic systems should be made.
A manual fire alarm system is one where the initial alarm is raised by a building occupant who activates a manual break glass point, a call point or a pull-station point.
An automatic fire alarm system relies on a system of smoke and heat detectors (most commonly, although other types of fire detection are possible). The detectors will be triggered by an instance of fire, or smouldering, and the information relayed to the control and indicating equipment, which activates the alarm sounders.
An automatic fire alarm system will sound whether or not the building is occupied whereas a manual system relies on the building being occupied for the alarm to be raised. Indeed, as a manual fire alarm system is a life safety system only, it would only need to be activated if people were present.
In part 134 of LWF’s series on fire engineering, we will continue to look at the different types of fire alarm system. 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 since 1986 to produce innovative and exciting building projects. If you would like further information on how LWF and fire strategies could assist you, please contact the LWF office on 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.