The monthly test has come back with a failure. Maybe the AOV vent did not open fully. Maybe the panel is showing a fault. Maybe the firefighter override did not do what it was supposed to do. Maybe the battery test came back below specification.
If you are the Responsible Person for the building, or the building manager, or the managing agent, this is the moment where what you do next matters. A failed test is not an emergency, but it is not something to ignore either. The legal, practical and safety consequences of handling it badly are significant.
This article walks you through what to do, in order, from the moment the test fails.
Step 1: Document the Failure
Before anything else, make sure the failure is properly documented.
What failed. Be specific. “The AOV did not open” is not enough. “AOV on Stairwell 1 at 3rd floor head did not reach full open position within 60 seconds during manual trigger test” is enough.
When it was tested. Date and time.
Who tested it. The engineer’s name and their competency credentials (manufacturer training, SMR01 registration, NICEIC, or other).
The panel’s state at the time of the failure. Fault codes, LED indications, audible alarms, battery voltage.
Photographs of any physical evidence. Actuator position, damper position, panel display, visible wiring damage.
This documentation is the basis for everything that follows. It tells the investigating engineer what to look for. It evidences your duty of care to the Building Safety Regulator or fire authority. And it becomes part of the Golden Thread record for the building.
Step 2: Check the Immediate Safety Position
Not all smoke ventilation failures have equal safety consequences. A faulty indicator LED is very different from a seized AOV actuator.
Ask yourself:
- Will the system still operate automatically if the fire alarm triggers?
- Will the firefighter override still work if the fire service uses it manually?
- Is there any risk that the system could activate inappropriately (opening vents when not required)?
The answers determine your interim measures. If the system is completely non-operational, you may need to put a fire watch in place, notify the Responsible Person immediately, and consider whether the building can remain in normal operation. If the system is partially degraded but will still function, the risk is lower but still needs to be managed.
This is the point where a competent engineer’s judgement matters most. If you are not sure what the failure means in practice, speak to a specialist before you make decisions about continued occupation.
Step 3: Diagnose the Root Cause
A competent engineer, ideally one trained by the smoke control manufacturer or SMR01 registered, should diagnose the fault and identify the root cause. Not just the symptom.
Common failure modes we see:
Actuator failure. The actuator has seized, the motor has burnt out, or the limit switches have drifted out of adjustment. Actuators are serviceable components with a finite life; they do fail, and they do need replacing periodically.
Wiring fault. A cable has corroded, a junction has come loose, or a cable has been damaged by subsequent building works. Particularly common where the smoke ventilation cabling shares routes with other services.
Panel fault. Electronic failure inside the smoke control panel, a relay, a PSU capacitor, a communications card. Sometimes repairable, sometimes requiring panel replacement.
Battery degradation. The panel’s standby batteries have lost capacity. Will not hold the building through a prolonged mains failure. Batteries should be replaced every 4–5 years as a matter of maintenance schedule, not after they fail.
Configuration drift. The cause and effect logic no longer matches the design. Either the panel was reconfigured without documentation, or changes to the fire alarm system have broken the interface.
Mechanical obstruction. A vent cannot open because something is blocking it. Could be debris, could be ice in winter, could be a pigeon nest.
Interface failure. The connection between the fire alarm and the smoke control panel has been broken, unintentionally or during unrelated works.
Without root cause diagnosis, any “repair” is guesswork. The engineer needs to identify specifically what failed and why, so the fix addresses the actual cause.
Step 4: Put Interim Measures in Place
If the system cannot be restored to full function on the same visit, interim measures are needed to manage the fire risk until the system is back online.
Typical interim measures include:
- Fire watch. A competent person physically patrolling the building, monitoring escape routes, and able to alert occupants if smoke is detected. Appropriate where the system is completely non-functional.
- Increased vigilance. A less formal version, building staff aware of the situation, residents notified if appropriate, and a clearer escalation procedure.
- Compensatory management arrangements. Changes to how the building is managed during the outage, agreed in consultation with the fire risk assessor or the fire authority.
- Occupancy restrictions. In serious cases, parts of the building may need to be closed until the system is restored.
These measures are proportionate to the fault. They should be documented, communicated to the Responsible Person, and removed as soon as the system is back to full compliance.
Step 5: Rectify the Fault
Once the root cause is identified, the remediation work is scheduled. Depending on what is required:
- Component replacement. Actuator, battery, PCB, damper motor, swap out the failed part with a certified replacement.
- Wiring repair. Replace damaged cabling, re-terminate joints, route cables out of harm’s way.
- Reconfiguration. Restore the correct cause and effect logic, verify against the design documents, record the change.
- Mechanical rework. Clear obstructions, repair weatherproofing, re-align mechanical components.
- Panel replacement. For legacy panels where repair is uneconomical or spare parts are unavailable, the complete panel may need to be replaced. See Replacing an Old Smoke Control Panel.
All rectification work should be documented. Photographs before and after. Parts used, with their DoP certificates if relevant. Engineer’s name and competency. Date and time.
Step 6: Re-Commission and Re-Test
After rectification, the system is not back in service until it has been re-commissioned and re-tested.
At minimum:
- The specific function that failed must be tested to confirm it now passes
- Any related functions must also be tested, in case the fault had wider effects
- A full cause and effect test is recommended if the fault involved configuration changes
- Battery standby duration should be verified
- The fire alarm interface should be confirmed operational
The re-test results should be recorded alongside the original failure documentation. This creates a clear evidence chain: failure → diagnosis → rectification → re-test → pass.
Step 7: Update the Records
The building’s fire safety records must reflect what happened. Specifically:
The fire safety logbook. The failure, the rectification, and the re-test all become entries in the logbook. The Responsible Person signs off that the issue has been resolved.
The asset register. If any components were replaced, the asset register entries for those components are updated with the new serial numbers, DoP certificates, and installation dates.
The Golden Thread. For higher-risk buildings, the building safety case is updated. The Building Safety Regulator expects to see evidence that failures are identified, addressed, and documented.
The maintenance schedule. If the fault suggests a pattern, actuators reaching end of life, batteries consistently underperforming, the maintenance schedule should be adjusted. Prevention is always cheaper than reaction.
Step 8: Ask Whether This Should Have Been Prevented
A failed test is a symptom. Sometimes it is just bad luck. Often it points to a wider problem with the maintenance programme, the building’s fire safety management, or the age of the installation.
Common underlying causes:
- Maintenance intervals too long between visits
- Testing regime too superficial, LED checks without functional tests
- Actuators past their service life and no replacement programme in place
- Panel at end of life
- Unmanaged building works damaging smoke ventilation infrastructure
- No clear ownership of the fire safety responsibility
If the same building has a pattern of failed tests, the answer is not “keep fixing them as they come up.” The answer is to fix the underlying cause, better maintenance programme, full panel replacement, clearer ownership, proper asset register.
See also: 11 Examples of Substandard Smoke Ventilation Maintenance and What Happens When a Smoke Control System Fails Maintenance Testing? for real-world patterns.
Need Help Now?
If your smoke ventilation system has failed a test and you need advice, technical guidance, or a replacement component, Vent Trade’s technical team can help.
- Call our technical team: 01202 725 689
- Email: info@vent-trade.co.uk
- WhatsApp: +44 7700 143933
- Browse smoke control panels and AOV products
All Ventec products are manufactured in the UK, BS EN 12101 certified, and held in stock for next-day delivery. Our technical department has been supporting UK smoke ventilation projects since 1988.
