A never-ending discussion - should we open roof smoke vents in the event of a fire sensed by a smoke detectors? If there is a water sprinkler system, do we still open the vents or allow the sprinkler system to operate and extinguish the fire?
The fire fighter wants the smoke vented to allow for clear site to evacuate the premises and clear air for him to do his job, the sprinkler supporters say let the sprinklers do their job first and then open the vents.
It has been proven that by opening the smoke vents first when a sprinkler system is in place can delay the operation of the sprinklers or even prevent them from operating at all due to releasing the built-up heat or causing sprinkler skipping.
A further debate is - should we open smoke vents by a thermal link or by the operation of the smoke detector system?
Far be it for me to offer a solution, but the one sensible answer offered me recently was:
- Where the fire design is primarily for life safety e.g. a shopping centre, the vents should be opened as quick as possible i.e. from a smoke detection system.
- In a property protection system i.e., a storage warehouse where a rapid-fire growth is expected, use manually operated vents and allow the sprinklers to do their job.
Where there is a low fire risk and property protection is the objective one can utilise a fusible link set at a temperature above that of which a sprinkler operates.