A fire alarm system is the building’s nervous system for fire. It detects the early signs of a fire, either automatically or when someone presses a call point, and turns that information into a warning loud and clear enough to get people moving, while telling the building management and fire service where the problem is. Almost every other fire safety measure, from lift homing to smoke control, takes its cue from the alarm.
This article sets out what a fire alarm system consists of, how it is organised, how it interacts with other building systems, and how it is regulated in Singapore through the SCDF Fire Code and the Singapore Standard for fire alarm installations.
What a fire alarm system does
An alarm installation has three jobs. It must detect a fire, either through automatic detectors or through people operating manual call points. It must warn occupants with sounders and, where needed, visual alarms, so they begin evacuation early. And it must communicate, showing at a control panel where the alarm originated and passing the signal to those who need to act: the building’s fire command centre, the management office and, in many buildings, the SCDF through an approved alarm monitoring company.
A good alarm system does all three with minimal false alarms. Unwanted alarms are not harmless; they cost time, disrupt occupants and, worst of all, teach people to ignore the sound. Much of the craft in alarm design lies in choosing detectors that respond to real fires in each space without reacting to steam, dust or cooking fumes.
The main components
- Control and indicating equipment — the fire alarm control panel, which monitors every device, decides when to raise an alarm, shows the location and records events.
- Automatic detectors — smoke, heat, flame and multi-sensor detectors, each suited to different spaces. Our guide to the fire detector types explains the choices.
- Manual call points — break-glass or resettable push units placed on escape routes so occupants can raise the alarm as they leave.
- Sounders and visual alarms — bells, electronic sounders, voice alarms and flashing beacons that warn occupants.
- Interfaces — input and output modules that connect the alarm to sprinkler flow switches, lift controls, door holders, fans and dampers.
- Power supplies — a mains supply backed by standby batteries so the system keeps working through a power failure.
- Wiring — circuits that are monitored for faults, often fire-resistant cable where the circuit must survive a fire.
Conventional and addressable systems
There are two broad architectures. In a conventional system, devices are wired on zone circuits and the panel knows only which zone has gone into alarm, not which detector. In an addressable system, every device has its own address on a loop, so the panel can show the exact detector or call point that operated, monitor each one individually and apply different settings in different rooms. Addressable systems dominate larger buildings because they locate fires faster and make faults easier to trace. Our separate piece on the addressable fire alarm compares the two in detail.
A third approach, wireless or radio-linked devices, is used where cabling is impractical, such as in heritage buildings, with the same fundamental functions.
Zoning, call points and audibility
A fire alarm system is organised into zones so that responders know where to go. Zone limits are set by the standard, typically restricting the floor area and number of storeys in each, so that a search does not cover too much of the building. Even with addressable devices, zones remain useful for display and for the cause-and-effect programming that decides what happens when an alarm occurs.
Singapore’s Fire Code 2023, in clause 6.3, sets several practical rules for manual call points. They are required on every storey, placed along exit routes, at exit staircase landings and next to hose reels, positioned so that no occupant needs to travel more than 30 metres to reach one, and mounted between 800 millimetres and 1.2 metres above finished floor level. Sounders must be audible and distinct from other signals throughout the protected areas, and visual alarms supplement them in places where a sounder may not be heard or noticed, such as toilets, car park floors and lift lobbies.
Integration with other building systems
When the alarm operates, many other systems respond. Clause 6.6 of the Fire Code requires lifts to be brought to a designated floor, usually the first storey, when the fire alarm activates. Smoke control fans start, air handling units shut down or change mode, fire shutters and smoke curtains deploy, magnetically held fire-rated doors release and access-controlled doors on escape routes unlock. Sprinkler flow switches report back to the panel so that a discharge is registered as a fire.
This cause-and-effect matrix is one of the most important documents in a building’s fire strategy, and it must be tested as a whole, not device by device. The alarm may also send status to the building automation system for monitoring, but the fire functions themselves should remain under the control of the fire alarm equipment.
Fire alarm system requirements in Singapore
The SCDF Fire Code sets out when an electrical fire alarm system is required. In broad terms, buildings other than residential purpose groups need a system once floor areas exceed thresholds set in the code for each purpose group, with the code specifying whether it must be automatic, manual, or both. The system must be electrically supervised and comply with SS 645, the Singapore code of practice for the installation and servicing of electrical fire alarm systems. Where required, it must be connected to the SCDF Operations Centre through an approved alarm monitoring company. The main panel is normally placed at the main entrance, in the fire command centre, in a guardhouse or in the fire lift lobby, with sub-panels in protected locations.
Homes are treated differently. Rather than a building-wide system, individual residential units are covered by the home fire alarm device requirement, explained in our article on the home fire alarm in Singapore. For other buildings, design is carried out by a Qualified Person as part of the fire safety plans, installation must be completed by a competent contractor, and wiring work falls under the electrical licensing regime administered by the Energy Market Authority. The completed system is tested and inspected before a fire safety certificate is issued, and it must be serviced and maintained throughout the building’s life.
Frequently asked questions
What is the difference between a fire alarm and a smoke alarm?
A smoke alarm is a single self-contained device that detects smoke and sounds its own built-in sounder, typically used in homes. A fire alarm system is a building-wide network of detectors, call points, sounders and a control panel that locates the fire, warns everyone and triggers other building systems such as lift homing and smoke control.
Which standard governs fire alarm installations in Singapore?
The SCDF Fire Code sets when a system is required and the key performance rules, and it refers to SS 645, the Singapore code of practice for the installation and servicing of electrical fire alarm systems, for detector type, spacing, zoning, wiring and servicing.
Why do lifts go to the ground floor when the fire alarm sounds?
The Fire Code requires lifts to be brought to a designated floor, usually the first storey, when the fire alarm activates. This stops people from using lifts to escape through a fire floor and leaves the lifts available to firefighters, who use dedicated fire lifts with protected power supplies.
How often should a fire alarm system be tested?
Routine testing and servicing are set out in SS 645 and the building’s maintenance regime, with regular functional tests of devices and a periodic full system check. Buildings holding a fire certificate must keep their fire protection systems properly maintained, and records of testing should be kept for inspection.
Do I need approval to change a fire alarm system during renovation?
Changes that affect fire safety provisions in a building generally require fire safety plans submitted by a Qualified Person and approved by SCDF. Moving partitions or ceilings often requires detectors and call points to be relocated, so the alarm layout should be checked whenever a fit-out changes the space.
Related reading
- Pre Action Sprinkler System: How It Works and Where Used
- Sprinkler Heads and Sprinkler Types: A Practical Guide
- Fire Sprinkler Systems: How They Work and When Needed
- HDB Listed Contractor (DRC): How the Directory Works
Planning alterations that touch fire protection, ceilings or structure? Talk to our consultancy or get in touch.
