How do fire and smoke dampers work?

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Fire prevention systems are made up of a variety of components, ranging from a simple ‘exit’ sign to the most complex sprinkler system.

In the event of a fire, both smoke and flame pose a risk. Containment is critical for a safe evacuation, reducing property loss and damage, and assisting firefighters in putting out the fire. Dampers play an important role in this.

Containing a fire

Fire walls and fire doors are highly efficient at controlling fires — as long as they are not broken. Good training should enable people to understand why propping open a fire door is a terrible idea, but what if the building’s structural standards allow for a breach?

To transport services from one location to another, the heating, ventilation, or air conditioning (HVAC) system must often cross a fire barrier. When this happens, dampers are used to preserve the barrier’s integrity. Dampers are found in the ductwork and ceiling cavities. If a fire breaks out, they are designed to close, preventing the spread of smoke and flames throughout the structure.

There are three types of dampers: Fire dampers, smoke dampers, and smoke/fire dampers. They operate in various ways and have distinct installation and maintenance requirements.

Fire dampers

A fire damper’s primary function is to keep flames from passing a fire barrier. They are positioned near the wall or floor, as appropriate, and form an integral part of the barrier that they protect. Fire dampers react to heat; when the temperature exceeds a specific level, the damper closes.

Smoke dampers

Smoke dampers respond to smoke detection and close automatically, and can be turned on and off remotely. They prevent smoke, toxic gases, and air from passing through a fire barrier.

Inhalation of smoke and toxic gases is the leading cause of death in the case of a fire, therefore keeping them contained for at least as long as the building is evacuated is essential.

Fire/smoke dampers

When it comes to protection, a combined fire/smoke damper is typically regarded as providing the best of both worlds. They are used when a duct must have both a fire damper and a smoke damper, and either high temperature or smoke detection is used to close the duct.

Combination dampers, unlike fire dampers, do not have a fusible connection and instead function on an electrical release once activated. This causes the damper to close more slowly, preventing pressure issues in HVAC systems.

Damper installation and maintenance

Dampers play an important role in limiting the spread of fire, smoke, and poisonous gases through structures. Proper installation and maintenance are critical – if a damper fails to function properly or only partially functions, it can mean the difference between life and death.

Take care of your dampers, and your dampers will take care of you. More information about our fire damper testing services can be found here.