Fire Dampers Will Not Work Like This

Have you ever thought about what would happen if a fire broke out in your building and reached your ventilation system?

Of course you should have fire dampers in your duct system but can you be 100% sure that they would prevent the fire from spreading?

Fire dampers are designed to prevent fires from spreading through your ductwork.   

Fire dampers are safety products used in heating, ventilation and air conditioning ducts. They are made from fire resistant materials and are designed to prevent a fire from spreading inside the ductwork. In reality, they could potentially save the lives of those living or working in your building.

How do fire dampers work?
The idea is that when a fire damper is alerted of an increase in temperature it closes to prevent the fire from getting through. This action usually occurs after the fusible link melts due to the raised temperature.

Fire dampers can also be alerted to the presence of a fire by an electrical signal from a fire alarm system. This of course requires the installation of detectors remote from the damper that sense heat or smoke in the building or duct system.

When installed correctly, fire dampers can prevent considerable damage, but the problem is that many buildings have fire dampers that have not been installed properly and are therefore not able to do their jobs.

Fire dampers are designed to close when either their fusible link melts or they are sent an electrical signal from a fire alarm system.

Your fire damper will not work if…

    • It is the wrong type of fire damper for the duct
      If the contractor you hired to install fire dampers in your ductwork did not install the right type of fire damper then you could be in trouble. Usually it’s a case of needing a spring loaded fire damper rather than a gravity fire damper.


    • There is large gap between the fire damper and the duct
      Common sense should tell you that if the gap between the fire damper and the duct is too large then the fire is going to be able to get through whether the fire damper is closed or not.


    • The blades have collapsed
      When the fuse melts, the fire damper’s springs are supposed to close the blades, but if the blades have collapsed or have been damaged in some way, they are not going to be fit for purpose.


    • The cassettes won’t operate
      If one of the fire dampers in your ductwork has cassettes that won’t operate, then your fire damper will not be able to close.


    • The springs have jammed or corroded
      The springs are designed to release the blades, closing the fire damper but if they are jammed or have corroded, they will not be able to carry out this action, which will ultimately result in the fire spreading through your system.


    • It has been jammed open
      If your fire damper has been jammed open with something e.g. a piece of wood (you may laugh but we’ve seen it happen) then it’s not going to be able to close, meaning the fire is going to pass through with ease.


  • It’s been installed incorrectly
    When it comes to installing fire dampers in ducting there is a right way and wrong way to do it. If your fire damper has been installed in the wrong airflow direction or even upside down (again we’ve seen it happen) it is not going to be able to stop the fire from passing through your ventilation system.

If your fire damper experiences any of these problems then it is not going to work properly, meaning the fire will continue to spread throughout your ductwork and cause greater damage to your building.

How to identify issues with your fire dampers
The best way to check your fire dampers and identify any issues is to get them tested. This is something you should already be doing on a regular basis.

According to the BS9999 Fire Damper Regulations, arrangements should be made for all fire dampers to be tested by a competent person on completion of installation and at regular intervals not exceeding two years (HTM03-1 requires hospitals to have their dampers tested every 12 months).

The regulations also require you to have your fire dampers repaired or replaced immediately if they are found to be faulty.   

Having your fire dampers drop tested
Can you guarantee that your fire dampers will close in the event of a fire? If you have not had your fire dampers tested for a while then we suggest arranging one as soon as possible. A fire damper drop test will reveal whether or not your fire dampers are working properly and will allow potential problems to be identified and resolved.

The Ductbusters team are highly experienced in carrying out fire damper drop testing and are more than happy to pay you a visit. We will be able to test all of your fire dampers and help you come up with a maintenance plan in order to comply with the BS9999 Fire Damper Regulations.

It’s important to get your ductwork and fire dampers cleaned on a regular basis.

Fire dampers cleaning
Problems with fire dampers often occur as a result of not being cleaned properly. If your fire dampers are not clean, a build up of dirt is likely to cause vital parts such as the springs and blades to jam.

Corrosion can also prevent fire dampers from closing properly but by having hiring professionals (like ourselves) to clean your ductwork and fire dampers on a regular basis, you can prevent this from happening.

Fire dampers maintenance
Creating a maintenance plan for your fire dampers will help to ensure they remain in a fully working condition. Over time it is likely that parts will need to be replaced so it is important to make sure that you have them checked by a contractor at least every two years.

When installed correctly and cleaned, tested and maintained on a regular basis, fire dampers have the potential to save lives. If you need the fire dampers in your ductwork testing, please get in touch with the Ductbusters team on 0800 085 0403 and we’ll arrange for our ventilation experts to pay you a visit.


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