What You Should Know About Fire, Smoke and Combination Dampers

With spring break right around the corner, now is the time to ensure that your campuses fire and life safety systems are properly maintained. Fire and smoke dampers are an important part of a building's fire and life safety protection system in the event that there is a fire emergency. However, with dampers hanging out in the ductwork, it’s easy to forget they are there and they may go too long without being inspected.

It may not seem like a big deal, especially with other fire protection features put in place. But fire and smoke can spread quickly, and one of the best ways for a smoke and flames to completely engulf a building is through the ventilation system. That’s why dampers have been specifically designed to help contain the fire as well as smoke to keep occupants safe while preventing unnecessary property damage. And as a facility manager you consistently hear that you need to have your facility's fire and smoke dampers inspected and repaired. There are tons of great articles about the top reasons why dampers fail and how often they need to be inspected. It’s all important information, but here is what you should know about the actual dampers themselves?

 

First off, there are three different kinds of dampers – fire dampers, smoke dampers, and combination dampers.

 

Fire dampers prevent the spread of fire within the ductwork through fire-resistance rated walls and floors. They work when the heat from the fire causes the normal temperature of a room to rise to about 165 degrees Fahrenheit. That heat causes the fusible link, which is holding the damper open, to melt and allows the damper to be closed. There are two types of fire dampers:

 

  • Dynamic Fire Dampers – Are installed in vertical barriers, where the HVAC system fan will continue to blow in the event of a fire. Because the fan will stay on, the spring loaded design helps the damper to spring shut against the air pressure.
  • Static Fire Dampers – Are installed in barriers where the HVAC system fan will shut off in the event of a fire. Because the fan will turn off, these dampers are designed like a curtain, allowing the damper to fall and shut due to gravity.

 

 

Smoke dampers resist the passage of air and smoke within the ductwork. They are typically operated by a smoke detector, which would also be located in the duct. Once smoke has been detected, the smoke detector sends a signal to the dampers actuator, which uses the jackshaft and linkage to open and close the blades of the smoke damper. There are two types of actuators:

 

  • Pneumatic Actuators – Need air to function properly
  • Electrical Actuators – Need power to function properly

 

 

To get the best of both worlds, combination dampers are used in areas where both fire and smoke barriers are located to prevent the passage of both fire and smoke between areas.

 

Dampers are a key component to your campuses overall fire and life safety plan. They help prevent the spread of fire and smoke by blocking access through the facility’s ventilation system. However, this means dampers are hidden from view, which means they are less likely to be though about. Dampers also have a tendency to frequently fail, which is why they must be maintained on a routine basis. According to the National Fire Protection Association (NFPA), “Each damper shall be tested and inspected one year after installation” and “The test and inspection frequency shall then be every 4 years”.

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