Everything You Need to Know About Air Control Dampers

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Air control dampers, while integral to every place we go in our everyday lives, remain a mystery to many of us. Whether at home, school, or work, AC dampers manage our environment to ensure we are comfortable and safe. Lloyd Industries, the leading manufacturer of AC dampers for over 35 years, is here to take care of your damper needs. Read on to illuminate your knowledge about air control dampers. 

What Are Air Control Dampers?

Air control dampers are devices that utilize blades, plates, or valves to regulate or stop the airflow within a duct, chimney, vent, or similar piece of equipment. AC dampers can also be utilized to stop airflow into unused rooms or areas. Fire dampers and smoke dampers and the combination fire/smoke dampers, specifically, can be used as protective measures to stop the spread of smoke or fire in a building’s ductwork.

How do Air Control Dampers Help the Air You Breathe?

You might not know much about AC dampers, but they improve your life every day. For example, when you go out to a restaurant, they keep the air in the dining area fresh from the conflicting scents from the kitchen. As you do your laundry, they assist in pulling the damp air from your dryer out of the laundry room so that mold and mildew won’t form. And in the case of fire, they shut down air ducts quickly, so that fire and smoke won’t snake through the ductwork and infiltrate the entire building in minutes.

What Types of Air Control Dampers are There?

There are two types of air control dampers: 

  1. Parallel blade air control dampers
  2. Opposed blade air control dampers

Parallel blade air control dampers have blades that rotate in the same direction, thus the name parallel. When open, they all open at the same angle. Upon closing, they close similarly to a louver shade, with each blade coming together on the back edge of the one below it. Parallel blades minimize pressure drop, making them the better choice for maintaining airflow.

Opposed blade air control dampers will alternate blade angles by neighbor, with even-numbered ones having one angle and odd ones having a different one. Similar to the parallel blades, the edges of the opposing blades will overlap when the damper closes. Because of tighter seals between each blade, opposed blade dampers are superior at modulating airflow at different junctures in air ducts.

How Do You Classify Air Control Dampers by Application Type?

There are many different types of air control dampers, based on what they are needed to do.

However, here are the main types of AC dampers:

  • Control dampers
  • Balancing dampers
  • Backdraft dampers
  • Multizone dampers
  • Industrial dampers
  • Safety dampers: fire dampers/smoke dampers/combination fire-smoke dampers

Control Dampers: Control AC dampers are meant to control airflow through the entire system and are installed at various points throughout the ductwork. Their blades will need to open or close fully many times during the day.

Balancing Dampers: Balancing AC dampers are needed to handle air pressure imbalances. Technicians will measure pressure in rooms, set the required balance, and lock the blades in place. This is usually done to reduce the instances of rooms that are difficult to heat or cool.

Backdraft Dampers: Backdraft AC dampers are used to restrict airflow in only one direction. Having shafts installed on one end of each blade turns the blade into a flap so that it will only open when air flows in the correct direction. In addition, they have a counterbalance to assist in making sure they only open at the correct time.

Multizone Dampers: Multizone air control dampers are utilized in buildings such as schools or small offices and are made of many dampers, each marked for a specific zone. This way, each multizone AC damper will handle an entire zone at once.

Industrial Dampers: Industrial air control dampers can handle much larger air pressures and constant temperatures above 250 degrees Fahrenheit. Being made from thick gauge materials, they are capable of withstanding extreme conditions. Factories and power plants utilize these because they require AC dampers that can handle maximum airflow.

Safety Dampers: Safety air control dampers, such as fire dampers, are specifically designed to close off the AC damper as soon as fire or smoke is sensed. This is to prevent the smoke and/or fire from spreading through the ductwork and to allow the building’s occupants time to escape the building safely during any fire and/or smoke event.

How is a Fire Air Control Damper Different?

Fire dampers are different because they are installed in the open position with a fusible link.fusible link is a valve that melts when the temperature exceeds a certain amount. Once this happens, the damper will be shut off, either by gravity or a spring. 

How is a Smoke Air Control Damper Different?

Smoke air control dampers can be installed in either open or closed positions, depending on what they need to do. If they are installed in a passive smoke system, they will be closed to prevent the circulation of air and smoke across a designated barrier. In an active system, they may be activated by fire alarms, smoke sensors, heat sensors, or whatever method the system’s owner has selected.

When Would a Fire and Smoke Combination Air Control Damper Be Needed?

Some building situations will call for a combined fire and smoke air control damper. This is when a barrier is rated for fire resistance and is also designed to manage the transfer of smoke.

Those cases would depend upon:

  • Fire resistance ratings
  • Leakage ratings
  • Temperature ratings
  • Operational ratings

For something that you might not have given any thought to, air control dampers are critical to our daily living. Whether they are automatic or adjusted manually, at work or at home, we utilize them for both comfort and safety. An essential mainstay of the HVAC system, we would be remiss if we did not pay attention to these mighty pieces of hardware in our building’s ductwork. 

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