Fire Dampers – Your Complete Guide

What are fire dampers?

Fire dampers are passive fire protection products used in heating, ventilation, and air conditioning (HVAC) ducts. They prevent a fire spreading throughout a building by closing off the ductwork and creating a sealed compartment with fire-resistant walls and floors.

How do fire dampers work?

Fire dampers contain a thermal element which melts when it detects a rise in temperature. The rise in temperature must be higher than the ambient room temperature. It must also be low enough to indicate early presence of a fire in the room. When the thermal element melts, the springs close the damper blades closing off the ductwork.
It’s that simple.

The dampers can also be connected to a building’s fire alarm system allowing them to operate automatically. When a fire alarm detector activates, a signal goes to the fire damper telling it to close.

What is the difference between fire dampers and smoke dampers?

Fire Damper Maintenance

A fire damper’s main purpose is to stop or delay the spread of fire through ventilation ductwork. It does this by creating a sealed compartment. This effectively contains a fire within a room (compartment) so it doesn’t spread throughout the building.

Fire dampers allow normal airflow when not in use. They instantly close on detection of a fire.

Smoke dampers work in effectively the same way. The most significant risk for people in a fire-based emergency is smoke inhalation. A smoke damper automatically closes on detection of smoke in a compartment, stopping the passage of smoke and toxic gases through a fire barrier. Smoke extract paths need installing in areas where people evacuate a building – so stairwells, corridors etc.

Which buildings use fire dampers?

They are typically in larger buildings such as:

  • factories
  • hospitals
  • retail premises
  • commercial premises
  • schools, colleges and universities
  • office buildings

Importance of fire damper maintenance

Fire dampers form part of a building’s life safety system and so needs maintaining in accordance with the Regulatory Reform (Fire Safety) Order 2005. All fire safety systems must have regular and professional maintainance to ensure they work at the time needed. A faulty fire damper will not inhibit the spread of fire throughout a building and can put lives at serious risk.

Fire damper regulations are in place to ensure companies install and maintain systems to set standards. BS 9999:2017 legislation states that ‘all fire dampers to be tested by a competent person on completion of the installation and at annual intervals. Spring-operated fire dampers should be tested annually, and fire dampers situated in dust-laden and similar atmospheres should be tested much more frequently, at periods suited to the degree of pollution.’

Testing is more frequent in buildings such as hospitals or high-risk environments.

Regularly maintaining and testing your fire dampers can save lives!

What does a fire damper test include?

A fire damper test requires both a visual inspection of the fire damper and a drop test.

A visual inspection of the system will:

  • check fire damper installation locations match the current records available.
  • inspect the damper to check for correct installation – for example, in position for the correct direction of airflow, and with no gaps around the installation.
  • check for any corrosion or damage to the fire dampers which would stop the device working correctly. If any corrosion is present, it should be replaced immediately.
  • check for any obstructions that may prevent the fire damper working correctly when activated.
  • check for any repairs required to the surrounding wall or ductwork that would affect the fire resistance.

A drop test checks the device operates correctly when activated. Manually triggering the thermal element or spring allows the testing of the device. All fire dampers should close fully when released. Any delay can impede the enclosure of a fire within a room.

The device is reset when the test is complete. The surrounding ductwork then needs cleaning to remove dust build up and the thermal elements need replacing if necessary.

Compliance with BS 9999:2017

Fire damper diagram


To demonstrate your compliance with BS 9999:2017, you should receive a fire damper testing report to show you have adequately maintained your fire safety system. This should detail when the testing was, along with photographic evidence of testing.

The report should also include all inspection results including corrective or remedial actions.

Who should maintain your fire dampers?

When it comes to maintaining your building’s fire safety systems it’s best to leave it to the experts. We have many years’ experience in maintaining and testing dampers here at Fire Plus Security. We cover London and surrounding counties for fire damper maintenance and testing. We fully inspect, maintain and test your systems in accordance with fire damper legislation. Any remedial works required to ensure the integrity of your safety systems remains intact are also highlighted.

Contact us today on 0208 544 9732 or


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