Fire Dampers

Fire dampers are critical passive fire prevention equipment used in air conditioning, ventilation, and heating systems.

A fire damper is meant to close automatically when heat from a fire raises the usual temperature of a room to 72 degrees, i.e. it is designed to close automatically when heat is detected. When the fusible link connecting to the damper melts, the damper’s door closes. They are positioned in “sleeves” in ductwork at the junction of fire-rated barriers in building zones such as partitions at the site of duct penetration to maintain the fire rating of the wall or floor. The fire damper protects the integrity of the existing barrier, limiting fire penetration before temperatures surpass the barrier’s fire rating threshold. Its principal role is to prevent fire from passing from one side of a fire-rated separation to the other. The damper is built to a high degree of integrity and is intended to withstand high temperatures for as long as feasible.

Intumescent fire dampers are passive air transfer dampers that expand to close their opening when exposed to high temperatures (intumescence). They are intended for fire resistance, open flame resistance, smoke resistance, or a combination of the two. Since air transfer fire dampers, unlike conventional fire dampers, are not covered by ductwork, their closing time is critical to prevent fire from flowing through while the damper is open.

In the case of a fire, dynamic fire dampers are fitted in vertical barriers, and the HVAC system fan continues to operate. As long as the fan is running, the spring-loaded construction allows the damper to close against air pressure.

Static Fire Dampers are installed where the HVAC system fan shuts down. The curtain damper is the most popular form, and it consists of a ‘curtain’ held up by a fusible link that allows the damper to fall and close due to gravity. The blades of multiple-blade dampers are placed in the airstream, and restricts airflow more than curtain types.

M&G Fire provides regular Fire / Smoke Damper Testing for businesses across Essex. If you would like to benefit from this service, please contact us for a free estimate at 01376 519 627 or via our contact form.