Keeping buildings safe includes preventing the spread of fires should they occur. While wall assemblies and doors have required fire ratings, penetrations through building walls are often a requirement of heating, ventilation, and air conditioning (HVAC) systems.
Fire dampers are essential safety devices installed in HVAC systems to prevent the spread of fire and smoke within a building. They are designed to close automatically when exposed to high temperatures, to block off airflow and contain the fire while maintaining the required fire rating for the entire wall assembly. Fire dampers play a critical role in maintaining building safety and protecting lives and property.
What is a Fire Damper?
A fire damper is a device installed in HVAC ducts or other fire-rated structures to provide passive protection in case of a fire. While active protection systems like sprinkler systems actively work to extinguish a fire, passive devices like fire dampers work to isolate and prevent the spread of fires.
A fire damper is similar to a traditional damper in its installation and ability to isolate airflow. Fire dampers contain a fusible link that is designed to melt when exposed to elevated temperatures, often 165 degrees Fahrenheit. When the fusible link melts, the fire damper closes, which isolates the air stream and helps to contain any fire.
Types of Fire Dampers and Applications
Fire dampers can be divided into a couple of different categories depending on construction style and operation:
Curtain vs. Multiple-Blade Fire Dampers
Fire dampers are available in two popular configurations: multiple-blade and curtain-style fire dampers. Both styles of dampers operate with the same fusible link principle, but the construction style of the damper varies. Curtain dampers have accordion-style blades that are pulled onto one side of the damper. When the fusible link is melted due to high temperatures, the curtain is released, which allows the damper to fully close.
Multiple-blade style dampers are different, in that the blades rotate in order to close off the airflow. The blades in these dampers share a common linkage which allows them to move in unison. An additional benefit of multiple-blade dampers is that they can be used in place of traditional balancing dampers to modulate flow rate.
Static and Dynamic Fire Dampers
Fire dampers can be designed to function properly either with the HVAC fans off or on.
With HVAC fans off, fire dampers rely on the force of gravity to fully close the fire damper. When the fans are on, fire dampers have to close against the additional pressure generated from the airflow through the ductwork. Static dampers are often unable to close with HVAC fans on because the force of gravity is insufficient.
Dynamic fire dampers can be used in these cases by using springs or other energy storage mechanisms to force the fire damper to the closed position. Designers often prefer using dynamic fire dampers when possible due to their increased versatility and performance.
A subset of dynamic fire dampers includes motorized fire dampers. These types of dampers incorporate a motor that allows remote operation and control. They can also be equipped with position indicators for operation verification, in order to make maintenance and testing more manageable. Motorized dampers are popular because of their reduced maintenance requirements due to the fact that fire dampers are often mounted in difficult to access areas of the building.
Testing and Maintenance of Fire Dampers
Due to the critical nature of fire dampers, the devices must undergo strict testing and maintenance protocols. The National Fire Protection Association (NFPA) sets standards for fire dampers requiring that they be tested and inspected after installation and before occupancy, one year after installation, and then every four years (or every six years for hospitals).
Limited access to dampers and complex closure mechanisms can make testing and maintenance difficult. You can help overcome testing challenges by understanding testing requirements beforehand and coordinating with the authority having jurisdiction (AHJ). The process of selecting the correct fire dampers for the application becomes easier when you understand the testing and maintenance requirements. Choosing the right type of fire damper, such as motorized or multiple-blade dynamic fire dampers, can make maintenance and testing procedures much more manageable.
AWV: The Trusted Name for Fire Dampers
Fire dampers are crucial components in any HVAC system. They provide an essential layer of protection against the spread of fire and smoke within a building.
Understanding the different types of fire dampers and their applications can help you make an informed decision when selecting the most suitable solution for your building's needs.
As a trusted provider of fire dampers, AWV offers a comprehensive range of fire damper options, including static, dynamic, motorized, multiple-blade, and curtain fire dampers. With our expert guidance and support, you can find the ideal fire damper solution for your specific requirements, to help ensure the safety and protection of your building and its occupants.
For more information on AWV's fire damper options and how we can help you choose the right solution for your needs, contact our team of fire damper experts today!
We look forward to assisting you with your fire damper requirements and ensuring your building remains protected against the spread of fire and smoke.
