The SCA Guidance on Maintenance of Smoke Control Equipment includes an appendix that we titled “Examples of Substandard Practice.” As chair of the working group that produced this guidance, I can say that every example in that appendix came from real situations encountered on real buildings.
These are not theoretical risks. They are things that are happening in buildings across the UK right now. If you are a building manager, responsible person, or maintenance provider, this article will help you recognise substandard work - whether it is being done on your building or by your own team.
1. Rewinding Smoke Extract Fan Motors
Rewinding electric motors is a common cost-saving practice in commercial HVAC. The motor is disassembled, and the copper coils and insulation are replaced. For a general-purpose ventilation fan, this is a legitimate repair.
For a smoke extract fan, it is a serious compliance failure. Smoke extract fans are certified products tested to operate at high temperatures for extended periods, with BS EN 12101-3 classes ranging from F200 through F300, F400 and F600 (the higher classes are required for car parks and tunnels). When you rewind the motor, the assembly is no longer the certified product - the replacement coils and insulation may not withstand the temperatures the original product was tested to. Under the Construction Products Regulations 2013, only certified products should be used in smoke control systems.
If your maintenance provider has rewound a fan motor rather than replacing it with a certified unit, the system may not perform in a fire.
2. Using Non-Certified Replacement Parts
This extends beyond fan motors to any component in the system. Actuators, vent hinges, damper seals, and even fasteners can be replaced with non-certified alternatives that look identical but have not been tested for fire conditions.
Non-certified parts may function perfectly under normal testing conditions and pass a visual inspection without question. They fail when exposed to the temperatures and conditions of a real fire - exactly when the system needs to work.
Every replacement component in a smoke control system should be sourced from the original manufacturer or a manufacturer who can provide certification for the specific application.
3. Holes in Compartment Walls Without Fire Stopping
During maintenance or other building work, openings are sometimes created in compartment walls to route cables, pipes, or other services. If these openings are not properly fire stopped, they compromise the compartmentalisation that the smoke control system relies on.
Smoke and fire can spread through unsealed penetrations, defeating the purpose of the smoke control system regardless of how well the system itself is maintained. The competent maintainer should inspect for unsealed penetrations during every 6-monthly visit and report them immediately.
4. Rewiring with Inadequate Cabling
Cables in life-safety applications are tested for heat, water spray, and impact resistance over specific time periods. When a smoke control system is rewired using standard commercial cabling rather than fire-rated cable, the wiring may fail under high temperatures - cutting power to the system at exactly the moment it is needed.
This is not always a deliberate cost-cutting decision. Electricians who are competent at general building wiring may not be aware of the specific cable specifications required for fire safety circuits. The competent maintainer should verify cable specifications as part of the annual inspection, checking compliance with ADB, BS 8519, and BS 7671.
5. Using Inadequate Support for Cabling
Even when the correct cable is used, inadequate fixings can cause cables to fall from walls or ceilings under high temperatures. Standard plastic cable clips will melt in a fire. Cables fixed to walls or soffits must have fire-rated anchoring and supports so they remain in place during a fire event.
Cables that fall during a fire can obstruct escape routes, entangle occupants or firefighters, and disconnect from their terminals - disabling the system.
6. Not Replacing Components Past Their Lifespan
Batteries, smoke detectors, and sensors all have finite lifespans that are not always obvious from visual inspection. A battery that has been in place for five years may show no external signs of degradation but fail to deliver the required current when the system switches to backup power.
The SCA guidance specifies that panel batteries should be no more than 3 years from their date of manufacture. If they are not dated, they should be replaced and labelled with the installation date. PLC batteries should be replaced every 2 years unless the manufacturer specifies otherwise. Detectors over 10 years old should be checked and replaced.
7. Failure to Conduct Regular Inspections
This is the most basic failure and the most common. Systems that are not tested regularly develop faults that go undetected. A damper that has seized, a detector that has drifted out of calibration, or a fan bearing that is beginning to fail - none of these problems announce themselves. They are only discovered through testing.
The SCA guidance sets out clear inspection intervals from daily visual checks through to annual full commissioning assessments. Neglecting any level of this regime allows faults to accumulate undetected.
8. Improper Calibration of Car Park Sensors
Car park ventilation systems use CO and NO2 sensors to monitor air quality and trigger smoke extract fans during fire events. These sensors require regular calibration by a competent person using manufacturer-approved test equipment.
Incorrectly calibrated sensors can fail to detect dangerous gas concentrations, delaying system activation during a fire. They can also produce false alarms that lead building managers to disable the system, creating a worse risk than the faulty sensor itself.
9. Ignoring Manufacturer Guidelines
Every smoke control system is supplied with installation, operating, and maintenance manuals specific to that system. These manuals contain critical information about maintenance intervals, lubrication requirements, battery replacement schedules, and software update procedures.
Disregarding these guidelines - whether through ignorance or convenience - can void the product certification, accelerate component wear, and lead to failures that a properly followed maintenance regime would have prevented.
10. Using Non-Competent Maintenance Personnel
BS 7346 Part 8 is explicit: a competent maintainer must have specialist knowledge of smoke control systems, adequate access to spares, and sufficient information regarding the system. General building maintenance staff, even those with broad fire safety experience, may not meet this threshold.
Following Dame Judith Hackitt’s call for improved competence in the building safety sector, the SCA established the SMR01 registration scheme specifically for smoke control maintenance organisations. SMR01 registration is independently accredited by UKAS and managed by KIWA. The SCA strongly recommends that only organisations whose engineers are trained by the smoke control manufacturer or are SMR01 registered are employed for smoke control system maintenance.
11. Failure to Update System Software
Modern smoke control panels use software-driven control logic. When components are replaced, the replacement parts may run a different software version than the existing system. If the maintainer does not recognise the incompatibility and update the system software accordingly, the replacement component may not function correctly within the system.
This is a growing risk as control panels become more sophisticated. Maintenance personnel need to be trained to perform firmware updates as per the manufacturer’s recommendations and to recognise signs of software incompatibility.
What Building Managers Should Do
If any of these practices have occurred in your building, the appropriate response is to commission a full system inspection by a Maintenance Engineer, one trained by the smoke control manufacturer or SMR01 registered. The inspection should verify system performance against the original design specification, identify any non-certified components, and produce a clear pass, pass with advisories, or fail outcome.
The SCA Guidance on Maintenance of Smoke Control Equipment provides the full framework for what a competent maintenance programme looks like. It is available from the Smoke Control Association website.
If you need an independent assessment of your smoke ventilation system, contact our team at Vent Trade.
Sources
Official guidance and standards referenced in this article:
