What is the Difference Between HVAC Dampers and Fire Dampers?

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When discussing your building plan with contractors, it is essential to note what dampers are necessary throughout the structure. Your HVAC (heating, ventilation, and air-conditioning) specialist may suggest fire dampers to you, depending on what type of building you have. What exactly is the difference between HVAC dampers and fire dampers?

What Do HVAC Dampers Do?

Quite simply, HVAC dampers are pieces of equipment connected to your HVAC unit, duct, chimney, or another control appliance of some kind that are meant to regulate airflow. These HVAC dampers have the ability to restrict the heating and cooling of any room or area and regulate the temperature within these specific rooms or areas in the home or building. They also control the amount of air entering and exiting the building.

What are the Different Types of HVAC Dampers?

There are several different types of HVAC dampers for different HVAC needs.

Here are a few of the common ones used:

  • Air control 
  • Fire  
  • Smoke  
  • Backdraft  
  • Smoke and fire combo

Air control dampers – Air control dampers, also known as volume balancing dampers, help in airflow control in buildings. Their blades will assist in regulating airflow inside a duct and may even stop all airflow if needed. These dampers are utilized when you need to control the amount of airflow into a room or area and also need to control the flow’s direction.

Fire dampers come in three types: static, dynamic, and combination. They are used when a building or home requires passive fire protection systems. The work within your HVAC system to prevent a fire event from progressing within your structure past the origin of the initial flames.

Smoke dampers, like fire dampers, are an integral part of a fire and smoke protection system within an HVAC system. However, unlike fire dampers, smoke dampers react to smoke rather than heat or flames. They also can be either opened or closed, depending on the type, so they can prevent smoke from passing further into the HVAC system or assist in funneling smoke and toxic gases out of the building or home.

Backdraft dampers are essential in ensuring that appliances are properly vented to rid areas of exhaust and potentially toxic gases. They also remove and replace unwanted stale air with fresh, clean air. These are essential in eliminating harmful fumes and vapors.

Combination smoke and fire dampers are, at times, necessary. These will operate in the presence of either smoke or fire. Often, these will be used in corridors and other high-traffic areas.

What are the Main Differences Between HVAC Dampers and Fire Dampers?

The main differences between HVAC dampers and fire dampers are that fire dampers are specialized dampers formulated to protect your home or building in the case of a fire event. They are passive dampers that operate in the case of a fire, as opposed to the user manipulating the blades to change airflow for personal comfort. HVAC dampers can be active in that the user can manipulate them at will, changing the airflow as needed at any given time.

How Do Fire Dampers Work?

Fire dampers are considered passive dampers, which means they operate independently; when triggered by a fire event, no individual needs to close them.

There are three different kinds, each working differently under specific conditions.

  • Static
  • Dynamic
  • Combination

Static fire damper – Static fire dampers are usually found within horizontal barriers and are generally a curtain-type design. These are utilized in HVAC systems that will shut off in the presence of fire. When a fire is detected and shuts down the HVAC system, this will cause the static fire damper will close because the air pressure will cease within the ducts. 

Additionally, as a second safety measure, these have a fusible link that will melt in the presence of heat, closing the fire damper when a set temperature is reached. The temperature is generally set at 165 degrees Fahrenheit. Still, in certain situations, such as kitchens and laundromats where the room’s temperature routinely reaches that threshold, the temperature will be set higher, at 212 degrees Fahrenheit. 

Dynamic fire damper – A dynamic fire damper is usually found in a vertical barrier. Unlike the static fire damper, these are made for HVAC systems that continue operating in the case of fire. They are spring-loaded, so they are capable of shutting against airflow.

Much like the static fire dampers, they are also able to close via the fusible link and are set up to have the fusible link melt at the 165-degree Fahrenheit threshold.

Again, this temperature can be altered depending on what type of building the HVAC system is being built into.

Combination damper – A combination damper is a smoke and fire combination damper. These will close when they sense extreme heat via the fusible link. Additionally, they have their own smoke detection system, which allows them to close if they sense any smoke. 

How Do You Care and Maintain HVAC Dampers?

HVAC dampers require regular maintenance. All manufacturers will be able to give guidance on what your particular damper requires. Some HVAC dampers will need to be checked every six months, while some, like fire dampers, need to be checked one year after installation and then every four years after. Some buildings, like hospitals, only require inspections every six years after the initial one-year review.

Most companies choose to have a professional do the inspection and to have one person in charge of keeping all maintenance records. Once you have your HVAC dampers on a regular schedule, you can rest assured that your HVAC system will operate at peak form!

HVAC dampers are the overall category of dampers utilized when building your HVAC system, and fire dampers are the specific dampers used when creating a passive fire protection system for your home or building. Lloyd Industries, an industry leader for over 35 years, would love to answer any questions regarding your HVAC needs. Additionally, if you are looking for a qualified HVAC contractor, we have a vetted list of professionals for your convenience.

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