Fire Suppression Systems – Smoke Exhaust Fans Interfacing

Combined Extract & Over Pressure VentRami recently asked the question “Can I use the sounder circuit to trigger smoke exhaust fans via relay?” to our Ask The Expert on www.conceptfire-uk.com

Our expert answered as follows:-

Unfortunately I can’t see how you could do this at the correct time as you would only need to operate the exhaust fans after a fire has been extinguished as operating them during a fire could potentially fan the flames.

We would always install a separate switch operated manually via a key, this
should not be powered by the control panel power supply but separately. Some Fire Suppression Panel manufacturers offer a relay to operate this from the panel, but not automatically.

To expand on the above answer and to explain further, operating a fan when a fire has been potentially detected would create a number of issues:-

1. Extract any Fire Suppression Gas Agents that are being used to extinguish the fire.
2. Provide additional Oxygen to the fire thereby fanning the flames.
3. Spread the fire to other areas as the fire is fed Oxygen.

The best way to operate any Smoke Extraction System is via a manual button preferably a key-switch and this should only be operated by a suitably qualified person after first asking the Fire Service for permission to extract.

For information on Smoke Extract Fans or Over Pressure Vents please contact us from our website Contact Us

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