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Two dampers can fulfill your requirements for smoke control. But which is better? Learn the difference between smoke dampers and fire-smoke dampers in this Newsstand article.
Passive Fire Protection in HVAC
Passive fire protection (PFP) creates safety corridors for occupants to evacuate during a fire event. Their primary goal is slowing the spread of flames and smoke, so that occupants have time to leave. This system is vital to your building’s design. Fire barriers and other PFP equipment will help fulfill this important requirement.
Your HVAC system will also play a role in passive fire protection. Life safety dampers will help slow the spread of flames and smoke through your HVAC system. Fire dampers prevent the spread of flames through the HVAC penetrations found in fire barriers, while smoke dampers slow the spread of smoke and noxious fumes through your ductwork. Fire-smoke dampers undergo testing for both scenarios and fulfill both functions.
In this article, we will compare two life safety dampers: the smoke damper and the fire-smoke damper. Both can meet smoke control requirements, but is one damper better than the other? Which damper type should you use for your system?
Smoke Dampers
Smoke is more dangerous than flames during a fire event. Smoke can quickly pass from room to room, endangering people outside of the fire area. If the smoke passes into a vent, it can easily spread through the entire building.
Smoke dampers close at the first signs of smoke, to prevent it from spreading through the HVAC system. Builders install these dampers at key locations throughout the ductwork. Each smoke damper comes with a smoke detector, which signals the damper to close when it senses smoke. For more details on smoke dampers, check out “What are Smoke Dampers?”
To be clear, fire-smoke dampers also have a temperature rating. However, they are also tested for fire resistance.
Although smoke dampers have a temperature rating, they cannot contain flames. Their temperature rating does not account for the intense heat of flames, especially near the fire's source. Testers bake smoke dampers for 30 minutes at 250- or 350-degrees Fahrenheit as part of their temperature degradation testing. This test shows whether the damper remains closed when heated smoke fills the duct.
Technicians will check the damper’s seals to ensure they can still block leakage through the closed damper, among other components on the damper. Testers conduct fire resistance tests on fire dampers and fire-smoke dampers. Each damper must withstand over 1700 degrees Fahrenheit for up to three hours.
Fire-Smoke Dampers
Engineers design and test fire-smoke dampers to prevent the spread of both flames and smoke. They can meet fire or smoke requirements. Therefore, they must meet UL 555 and UL 555S standards, requiring testing to both standards.
To put that into perspective, a fire-smoke damper must complete the fire resistance test and the temperature degradation test, as well as the other tests conducted under each standard. It is important to know that the damper will stay intact whether it closes against smoke or flames. The fire-smoke damper will be a vital part of the passive fire protection system during an emergency.
Fire-smoke dampers are designed and tested to resist both dangerous elements.
A smoke detector and a fire response device connect to these dampers, allowing them to react to either element. This makes them a versatile choice for meeting fire safety requirements.
Which is Best?
It may seem like a straightforward choice. Fire-smoke dampers meet both requirements. They react to flames and smoke and receive testing for both scenarios. You want to maximize safety for the people in your building. Fire-smoke dampers may seem like the best approach, but there are a few things to consider. The best way to understand the difference is to separate the two functions of the fire-smoke damper.
Install fire dampers at the fire barrier to help maintain the barrier's fire rating. You can also install a fire-smoke damper at the fire barrier to meet this requirement. Here, the fire-smoke damper should close and withstand flames.
You may think that the damper will also resist smoke coming from the fire, so that you’re containing smoke at the source. Remember that the heat degradation test the damper's components for a maximum temperature of 350 degrees Fahrenheit. The heat produced by the fire will exceed this maximum. The guarantee covers the damper's seals against heated air, but not the flames. When closing against flames, the fire-smoke damper acts as a fire damper.
The system's designers add smoke dampers throughout, to comply with smoke control codes and standards. These dampers automatically close at the first signs of smoke, but first responders can reopen them to help control smoke flow through the system. Smoke control is important during fire suppression. Firefighters may need access to an area of the building that is filled with smoke.
Smoke dampers are not rated for fire resistance. They are rated for smoke control.
Smoke dampers can reopen and allow fans to blow the smoke to other, unoccupied areas of the building. This provides a safe area for firefighters to continue combating the flames. We can also use fire-smoke dampers for smoke control. Technicians can configure them to reopen upon receiving a signal, allowing the HVAC system to help clear the area for first responders.
In this scenario, we use the fire-smoke damper as a smoke damper. If the fire-smoke damper is near a fire barrier, then first responders will need to make sure the damper isn’t involved in fire containment before reopening.
Note that fire-smoke dampers will be more expensive because they require installed fire and smoke detection systems. They must be prepared to detect both elements. This holds true whether the damper contains fire or smoke. We equip smoke dampers for the specific scenario.
Combination fire-smoke dampers are rated for fire resistance and smoke control. They are designed to handle both hazards.
You may find areas in your building designed for both scenarios. In these cases, the fire-smoke damper will be your only option. The key is understanding the project. Familiarize yourself with the codes and standards.
Make sure that every damper meets the needs of your building. We build smoke dampers and fire-smoke dampers to ensure the safety of your building's most important asset: its occupants.
Air Balance and Life Safety Dampers
At Air Balance, we build dampers to meet your requirements. Whether you need to keep air moving through your ducts, or you need to keep people safe during an emergency, we can build the best solution for you. We are a collective of top-tier brands, building louvers and dampers for commercial HVAC projects. Contact Air Balance today, and let’s work together on your next project.
Which do you use more? Are fire-smoke dampers always a viable choice? Share your thoughts in the Comments section below. We want to hear from you!
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