A smoke damper prevents the spread of toxic smoke and gases throughout an HVAC system by closing when smoke is detected. A fire/smoke damper does the exact same thing but adds a heat-sensing mechanism, ensuring it also shuts to contain flames and maintain structural integrity during a fire.
Smoke dampers are provided with leakage and temperature ratings. A combination fire/smoke damper is used when a barrier is both rated for fire resistance as well as designed to restrict the transfer of smoke and will meet both the fire damper and smoke damper requirements.
A fire damper closes once the duct temperature reaches a high enough level to melt a fusible link. A smoke damper closes upon the detection of smoke. The codes have rec- ognized, and most engineers agree, that the best method of compartmentalization is through the use of the combination fire/smoke damper.
Fire dampers, smoke dampers, and combination fire/smoke dampers are critical to preserving life when fire threatens. Choosing between dynamic and static types, and employing these dampers ensures building safety and code compliance!
Buildings are divided into fire-resisting compartments using walls, floors and ceilings designed to resist fire for a set period, typically 30, 60 or 120 minutes. Fire dampers exist to ensure that ventilation systems do not undermine this compartmentation.
How to Do It: Wait until all embers have extinguished and the fireplace is no longer warm to the touch. Closing the damper too soon can trap smoke and carbon monoxide inside your home, creating a dangerous situation. Safety Tip: Always double-check that the fire is completely out before closing the damper.
Q: Are fire dampers required in one-hour fire-rated walls if the facility is fully sprinkled? A: According to NFPA 90A (1999 edition), one-hour fire-rated barriers do not require fire dampers in fully ducted HVAC systems, unless the one-hour fire-rated barrier is a vertical shaft.
The $5,000 rule is a guideline to help homeowners decide whether to repair or replace their HVAC system. You multiply the age of your unit by the cost of the needed repair. If that number exceeds $5,000, replacing your HVAC system is often more cost-effective.
As noted, there are 2 types of fire damper, the fusible link curtain type and the fusible link multi-blade type. Usually, for closing, the multi-blade would be used for larger ductwork installations where it would be difficult to reset the curtain/drop type damper or fir dynamic airflow conditions [fans running].
A vibration damper typically lasts between 5 and 15 years, depending on the type of damper, operating conditions, and maintenance practices. Rubber-metal dampers generally last 8–12 years, while air springs can function effectively for 10–15 years with proper care.
Generally, fire dampers are required where air ducts penetrate walls that are rated for 2-hours or more. They are needed in all air transfer openings (non-ducted) in rated walls, regardless of the rating.
For a Hotter Fire
Fully open the damper to maximize airflow. It provides ample oxygen to the fire, resulting in a more intense and hotter burn. The damper must be fully open when lighting the fire.
Fire dampers (or fire shutters) are passive fire protection products used in heating, ventilation, and air conditioning (HVAC) ducts to prevent and isolate the spread of fire inside the ductwork through fire-resistance rated walls and floors.
Use a fire damper when ductwork penetrates passive fire-rated barriers (like fire walls and floors) to prevent flames from spreading. Use a fire-smoke damper when the barrier is rated for both fire and smoke, and smoke control or pressurization is required to keep egress paths clear.
Out of wall “OW” combination fire smoke dampers are designed so that the leading edge of the damper frame can be up to 8" (203) out of the wall, partition or masonry floor.
As we have seen, smoke dampers are operated by an actuator, which is triggered by a system activation. Once this happens, the smoke dampers will open or close, depending on their type and the necessity of their action.
The "two-foot rule" in HVAC is a duct design and installation guideline that requires a minimum of 24 inches of straight, uninterrupted space between branch take-offs (where air taps off the main trunk). It is also applied to spacing branches away from end caps, transitions, and the main plenum.
Fire dampers are generally not required for ducted penetrations in 30-minute walls, as model building codes (like the IBC and NFPA 5000) typically only mandate fire dampers when ducts penetrate walls with a fire-resistance rating of 222 hours or more.
Expect to pay an average of $350 to replace a motorized HVAC damper, with a typical range of $250 to $450. However, you could pay as little as $100 or as much as $600. A motorized damper regulates the airflow inside your HVAC system, which in turn controls the temperature in your home.
Fire dampers are held open by fusible links. A fusible link is rated specifically for temperature indicative of fire, above the design ambient temperature of the HVAC system. If a fusible link breaks and is not replaced with the proper rated component, the fire damper may fail to close under fire conditions.
A fire damper typically looks like a metal sleeve or frame housing a folded steel curtain or a set of rotating blades, fitted with a prominent heat-sensitive silver piece called a fusible link. They are usually hidden inside ductwork or behind wall/ceiling vents.
Fire dampers must be inspected and tested exactly one year after installation. After the initial check, standard building types require inspections every 4 years. If the building is a hospital or Group I-2 healthcare facility, the inspection interval is extended to every 6 years.
Many Amish homes are built with plenty of windows to help circulate the air and bring in the cooler overnight temperatures. They open the windows on the top floors to help the heat escape while the family retreats to the lower grounds within their homes for comfort.
The most expensive part of an HVAC system depends on whether you are replacing an air conditioning component or a heating component:
The "20-degree rule" in HVAC has two meanings: it refers to the physical limit of the air conditioner (how much it can cool the air) and a thermostat guideline (how much cooler your home should be than the outside temperature).