Smoke and Heat Venting
Smoke and heat exhaust ventilation systems (SHEVS) release fire smoke and heat to the outside in a controlled way to keep escape routes clear of smoke, assist the fire brigade and support earlier, more localised sprinkler activation.
How it works
Without venting, hot smoke and combustion gases accumulate under the ceiling, reducing visibility on escape routes, hampering the fire brigade’s attack, and, through trapped heat, potentially triggering many sprinkler heads simultaneously over a wide area instead of confining the fire locally. Natural or powered smoke and heat exhaust systems relieve the smoke layer in a targeted way through roof openings or fans, keeping the thermal load on the structure lower.
Design and interaction with extinguishing systems
Sizing depends on fire load, ceiling height and smoke compartment size. A known conflict exists with sprinkler systems, since venting that activates too early or too strongly can reduce the cooling effect of extinguishing water on the seat of the fire. Modern concepts therefore coordinate sprinkler and venting activation rather than designing them independently.
Insurance relevance
Functioning smoke and heat venting limits smoke and heat damage beyond the immediate fire zone and therefore affects loss estimation for property and business interruption risks. Maintenance deficiencies in release mechanisms and drives are among the most common findings when such systems are inspected during risk surveys.