When reviewing building schematics, it is always important to verify that fire regulations are being followed and that your home or building is up to code with fire dampers and smoke dampers in place. While these dampers are essential to keep occupants unhurt in case of a fire, they also play a part in keeping people safe with an eye to indoor air quality. So, let’s take a closer look at smoke dampers and how they can assist in keeping indoor air quality breathable during a fire event.
What Are Smoke Dampers?
Smoke dampers are a part of a building’s overall fire protection system. They help reduce and prevent the spread of smoke and other toxic gases throughout a building when a fire occurs. Heating, venting, and air-conditioning (HVAC) specialists install smoke dampers into air conditioning and ventilation ductwork or into the physical fire and smoke barriers, such as walls, floors, or ceilings.
How Does a Smoke Damper Work?
Similar to fire, smoke can rapidly and readily spread throughout a building. Since smoke rises, one of the fastest ways for it to spread is through a building’s ventilation system. With smoke inhalation being a leading cause of death during a fire, preventing the spread of smoke is primary to keeping occupants safe while evacuating them when a fire breaks out.
Smoke dampers are specifically designed to prevent the passage of smoke and toxic gases between sections of ductwork. Most smoke dampers are set up to be activated by the fire or smoke alarm system and will be triggered upon the detection of smoke. Others can be set off remotely. Once they have been activated, they will close and thereby will not allow the passage of smoke or any other gases to move any further along in the ductwork or through the smoke barriers.
How Does a Smoke Damper Affect Indoor Air Quality?
A smoke damper is your first line of defense to protect indoor air quality during a fire. Once smoke is detected, the smoke damper will close tightly, preventing the smoke and any other toxic gases from moving any further in the ductwork or through the smoke barrier, thereby containing it in one area. This will protect the indoor air quality of the rest of the building from the smoke and gases, allowing the occupants the critical time needed to evacuate safely.
Smoke barriers can be a:
- Wall
- Floor
- Ceiling
Smoke dampers can be installed in either smoke barriers or within the HVAC ductwork itself.
What is Different Between a Fire Damper and a Smoke Damper?
Both smoke dampers and fire dampers are part of a comprehensive passive fire protection plan for your HVAC system. While the smoke damper will close to prevent smoke and other toxic gases from moving further within the ductwork, a fire damper will shut down to prevent an actual fire from progressing through the ductwork.
How Does a Fire Damper Work?
When a fire is detected, and the heat in the room rises to a preset level, the fusible link on the fire damper melts, causing the damper to close. For most fire dampers, the fusible link temperature setting will be 165 degrees Fahrenheit. However, in some cases, such as kitchens or laundromats, where the room temperature will routinely rise to that level, the temperature setting will be set higher, generally to 212 degrees Fahrenheit.
Once the fire damper closes, the air circulation is cut off and stops the oxygen supply to the fire at its source. This will prevent the fire from spreading any further. Fire dampers are critical components in any building HVAC system’s fire prevention system.
What Types of Fire Dampers Are There?
There are three types of fire dampers, all achieving the same goal of not allowing the fire to move past its primary source. These are:
- Static
- Dynamic
- Combination
Static fire dampers – Static fire dampers are considered a curtain style. Once your building’s fire detection system detects a fire, it will trigger the HVAC system to turn off. Once the HVAC system is shut off, the lack of a fan will cause a loss of air pressure, triggering the curtain fire damper to close. Once it is closed, no air or flames can pass through the ducts of your HVAC system.
Dynamic fire dampers – Dynamic fire dampers are spring-loaded, which means they are held in place by the fusible link. Unlike static fire dampers, dynamic fire dampers are installed in HVAC systems that will not shut off automatically during a fire event. Instead, air will continue circulating throughout the HVAC system, even when there is a fire. Once the fire damper detects the heat of the fire, the fusible link melts, and the spring-loaded system will close the damper.
Combination dampers – Combination dampers combine both smoke dampers and fire dampers into one. These dampers activate once extreme heat is detected. They also have their own smoke detection system that will trigger them to close. These dampers operate independently from the HVAC system, similar to how dynamic fire dampers operate.
How Often Do Smoke Dampers Have to Be Inspected?
Both fire dampers and smoke dampers need to be maintained and inspected. Once you have had them installed, you need to have them inspected one year later. After the first year, smoke dampers only need to be inspected once every four years. There are some exceptions, such as hospitals, where the inspections only need to be every six years. Make sure to keep good records of all inspections and testing of your building’s smoke dampers.
When concerned about protecting indoor air quality in your building, smoke dampers are your first line of defense against fire, smoke, and toxic gas events. They can be operated either remotely or by having them tied into your building’s fire alarm system.
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