Smoke causes over 80% of fire deaths, so fire smoke exhaust fans are a critical part of life-safety systems. The company's smoke exhaust fans are built to run continuously for more than 1 hour at 280°C, keeping escape routes and firefighting access clear while the building is evacuated.
What a Smoke Exhaust Fan Must Do
During a fire the priority is not comfort but survival. A smoke exhaust fan removes hot, toxic gases from a protected volume so that occupants can see and breathe along escape routes and so firefighters can enter. The fan must keep turning even when the surrounding air is far above the temperature of a normal HVAC duty, which is why a high-temperature rating is the defining requirement rather than a secondary feature.
In many codes the reference performance is operation at 280°C for at least 60 minutes, sometimes 300°C or 400°C for 2 hours in larger or higher-risk buildings. The fan, its motor, and the drive set must all withstand that thermal load without seizing or losing balance. A unit that stops after a few minutes has failed its only real job, no matter how quietly it ran beforehand.
European projects commonly reference EN 12101-3 for powered smoke and heat exhaust ventilators, which sets out the test regime for high-temperature integrity. Specifiers working on metro, tunnel, or high-rise projects should confirm the quoted rating maps to the relevant clause of that standard rather than a generic claim, because the test method is what makes the number meaningful.
The fan also has to interface with the fire alarm and fail to a safe state, so that on detection it starts automatically and reports its status. A smoke fan that needs a person to switch it on is not a life-safety device; the control is part of the rating, not an accessory.
Key Operating Parameters
The table lists the figures that determine whether a fan is fit for a given fire strategy, and that a consultant will check at design and again at commissioning.
| Item | Specification | Note |
|---|---|---|
| High-temp rating | 280°C for 60+ minutes | continuous operation in smoke |
| Acoustic level | below 75 dB(A) | suitable for hospitals, schools |
| Airflow | up to 60,000 m3/h | per single fan, project dependent |
| Pressure | up to 1,200 Pa | duct and shaft resistance |
| Construction | hot-dip galvanised steel | corrosion resistance in shafts |
Fans for this duty are usually arranged with the motor outside the hot gas stream or cooled by a dedicated circuit, and the impeller is dynamically balanced to a tight grade so it stays stable as it heats. The control system should fail to a safe state and interface with the building fire alarm so the strategy is automatic.
Because the units sit idle for most of their life, regular functional testing on a scheduled basis is what proves they will run when needed. A fan that has never been exercised is a risk, however good its certificate.
Specification Checklist
Designers specifying smoke exhaust should confirm the following before procurement, since these points separate a real life-safety fan from a comfort fan pressed into service.
- Confirm the rating: match the required temperature and duration to the local fire strategy, not a catalogue default.
- Check the standard: ask for evidence against EN 12101-3 or the applicable national test, with the certificate number.
- Plan the motor position: decide whether the motor sits in the airstream or in a cooled compartment.
- Integrate the control: the fan must start automatically on fire alarm and report status to the control panel.
- Allow access: size the shaft and access door so the unit can be serviced after commissioning.
Where the Fans Are Used
These fans protect spaces where large numbers of people gather or where a fire would spread quickly: metro stations, hospitals, shopping centres, and underground car parks. In a metro station the exhaust strategy also supports normal ventilation, so the same equipment serves daily air quality and emergency smoke control, which is why the duty and the rating must be designed together.
The life-safety role means the fan should be selected and installed as a system, not a loose component. Regular functional testing, typically on a scheduled basis, confirms it will run when needed, and the fire strategy document should name the exact model and rating so substitution cannot weaken the design.
For owners, the quiet benefit is that a verified smoke exhaust fan shortens the time a building is out of use after an incident, because insurers and authorities can see the protection was real.
Owners specifying smoke exhaust should also plan the ongoing proof, because a rating is only real if the fan is shown to still run when called. A sensible regime is a periodic functional test where the fan is started from the fire signal and its current draw and run time are logged, so a failing bearing shows up as a trend rather than a silence during an incident. Specifiers should ask suppliers for the test report that backs the quoted high-temperature rating, and for the certificate number, so the procurement file is complete before the authority reviews it. The cheapest fan with the weakest paper is the most expensive over the life of the building, since a failed inspection can halt occupation and a failed fan can cost lives, which is why the evidence matters more than the headline figure.
Keruite engineers respond to selection enquiries within 24 hours, backed by the factory's own performance testing laboratory and more than 30 years of fan manufacturing experience.
