How to commission a fire alarm system
The commissioning process under BS 5839-1 — pre-commissioning checks, functional testing, cause and effect verification, documentation, and handover requirements.
Commissioning is the process by which a newly installed fire alarm system is verified as complete, correctly installed, and fully functional before it is handed over to the building owner. BS 5839-1 sets out detailed requirements for commissioning — it is not simply a matter of switching the panel on and confirming the alarm sounds. Every device, every circuit, and every programmed function must be tested and verified.
The Commissioning Process Under BS 5839-1
BS 5839-1 requires commissioning to be carried out by a competent person — typically the installing contractor or a specialist commissioning engineer. The standard defines commissioning as a systematic process of inspection, testing, and verification that confirms the system meets its design specification and operates correctly in every respect.
Commissioning follows installation but precedes handover. The system must not be handed over to the building owner as operational until commissioning is complete and all required tests have passed. Commissioning a system with known deficiencies and handing it over as complete is a serious breach of the standard.
Pre-commissioning checks
Before Commissioning Begins
Before functional testing commences, the commissioning engineer must carry out a series of pre-commissioning checks to verify the installation is ready:
| Pre-commissioning check | What is verified |
|---|---|
| Installation completeness | All devices, cables, and panels are installed in accordance with the design drawings; no outstanding installation work remains |
| Cable continuity and insulation | All cables tested for continuity and insulation resistance; no open circuits, short circuits, or earth faults present |
| Device base wiring | All detector bases and sounder bases correctly wired with correct polarity |
| Power supply | Mains supply present and correctly connected; standby battery installed and charging; supply voltage within panel specification |
| Panel configuration | Panel programmed with correct zone configuration, device addresses, cause and effect programme, and text labels |
| ARC connection (if applicable) | Digital communicator installed and configured; ARC notified and ready to receive test signals |
Functional testing
Functional Testing of All Devices
Once pre-commissioning checks are complete, every device in the system must be functionally tested — not just visually inspected, but physically activated and verified to produce the correct panel response.
Detectors are tested using an approved test aerosol (for smoke detectors) or a heat gun (for heat detectors). Each detector is activated individually and the panel response is verified: the correct device or zone should alarm, the correct text label should display on addressable panels, and all programmed outputs for that device should activate.
Manual call points are tested using the test key to simulate a glass break. The same panel response verification applies.
Sounders and visual alarm devices are verified for correct operation. On addressable systems, sounders may be individually addressed and must each be verified separately. Sound level measurements should be taken to confirm the required levels are achieved throughout the building.
Ancillary outputs — door releases, lift recall, ventilation shutdown, suppression system triggers — are verified to operate correctly in response to the appropriate alarm condition. This requires the relevant ancillary systems to be available and ready for testing.
Cause and effect verification
Verifying the Cause and Effect Programme
On any system with programmed cause and effect relationships — which includes all addressable systems of any complexity — the commissioning process must verify that every programmed relationship operates correctly. This means activating each input (detector, call point, or input module) and verifying that every programmed output responds as specified in the cause and effect matrix.
For complex systems with many input-output relationships, this is a significant element of the commissioning process. A cause and effect matrix with 50 inputs and 30 outputs requires verification of potentially 1,500 individual relationships — many of which will be inactive for most combinations but must still be confirmed correct. See our cause and effect guide for more detail on the matrix and its programming.
Commissioning documentation
Required Commissioning Documentation
BS 5839-1 requires the commissioning engineer to produce a complete set of commissioning documentation on completion. This documentation is handed to the building owner as part of the system handover and must be retained. It includes:
- Commissioning certificate — signed by the commissioning engineer confirming the system has been installed and tested in accordance with BS 5839-1 and the design specification
- As-installed drawings — site plans showing the actual positions of all devices, zones, and cable routes as installed (which may differ from design drawings where field changes were made)
- Equipment schedule — a full list of all installed equipment with manufacturer, model, and quantity for each device type
- Zone plan — the plan for display at the control panel
- Cause and effect matrix — the complete programmed input-output relationship table
- Test records — records of all pre-commissioning checks and functional test results
- Operating and maintenance instructions — panel operation manual, maintenance requirements, and log book
Handover
System Handover
Handover marks the formal transfer of the commissioned system from the contractor to the building owner or their representative. At handover, the commissioning engineer should:
- Demonstrate the system operation to the nominated responsible person
- Explain the weekly test procedure and provide or demonstrate the test key
- Hand over all commissioning documentation
- Confirm the log book is in place and explain what must be recorded
- Notify the ARC that the system is now live (if applicable)
- Confirm the maintenance contract arrangements
Common questions
Frequently Asked Questions
No — commissioning can be carried out by a separate commissioning engineer, which is common on larger or more complex projects where independent verification is desirable. The commissioning engineer must be a competent person with appropriate training and experience. On smaller installations, the installing engineer typically carries out commissioning as part of the installation contract. What matters is that the commissioning is complete, documented, and carried out by someone with the competence to do it correctly.
This is a common pressure on construction projects and one that should be resisted. An uncommissioned fire alarm system may have devices that do not activate, zones that do not alarm, or cause and effect relationships that do not operate. Occupying a building with an uncommissioned fire alarm system creates significant legal and safety risks. Where partial occupation is unavoidable, only the commissioned and verified portions of the system should be relied upon, with alternative precautions in place for the uncommissioned areas. This must be documented and agreed with the fire risk assessor.