Five Specialty Dampers for HVAC Design

Not all HVAC systems are the same. Each system will have a unique design with specific requirements. Certain specialty dampers are designed for specialized applications. Learn more about five specialty dampers for designing HVAC. 

Specialty Dampers

HVAC design requires more than regulating airflow. You will also find that certain applications will have unique requirements. For instance, you may have spots in your HVAC system that have pressure imbalances.

Or there may be places in your system where air should only flow in one direction. If you're designing a system for an industrial project, then you will need heavy duty dampers. For these unique applications, you will need specialty dampers to meet requirements.

Starting a project? Not sure what you need? MCDLG can help. Contact us today and tell us about your project.

Balance Dampers – For Balancing Pressure

There may be places in your HVAC system where negative and positive pressures are imbalanced. This imbalance will cause several issues in the connected rooms, like spots that never seem to warm or cool and doors that close on their own. An imbalance left unchecked can lead to serious issues down the road.

Balance dampers are designed to balance air pressure and keep airflow moving efficiently through the system. These dampers do not regularly open and close like control dampers. The blades of balance dampers are adjusted once to a specific angle and then locked into position. Operators will adjust the angle of the blades and measure the changes in air pressure between the connected rooms. Once adequate pressure is achieved, the damper’s blades are locked to maintain the necessary pressure.

Balance dampers typically use a manual hand quadrant, since adjustments will be rare. Manufacturers may offer other options for adjusting the blade angles. Balance dampers help your system achieve efficient airflow by eliminating any imbalances in the system.

Backdraft Dampers – For Single Direction Flow

As you design your HVAC system, you will find that certain areas only need airflow in one direction. For instance, you will have exhaust points where air is moved out of the building. There is a specialty damper for these situations: the backdraft damper.

Backdraft dampers have a special blade design with an off-center blade axle, which run through one end of the blade instead of its center. This turns the damper's blades into flaps that can open with airflow and stay closed when it stops, or if airflow moves in the wrong direction. Backdraft dampers can regulate airflow without an actuator.

A counterbalance weight can assist the opening action or resist it. This can be useful if you need the damper to fully open with little airflow, or if you only want it to open when the necessary airflow rate is achieved. This can be an efficient option for intake and exhaust points. Consider adding backdraft dampers for these applications.

Industrial Dampers – For Industrial Applications

If you’re designing HVAC for a factory, then you will have serious requirements. Your system will need to heat and cool large spaces. You will need HVAC equipment that can operate under high static pressures and extreme temperatures. For instance, you may need a damper to operate while subjected to 20 inches w.g. of static pressure. Or you may need dampers that can handle air that reaches 450°F on a regular basis. A standard damper won't be able to handle these applications. This is where industrial dampers come in.

Industrial dampers are designed and built for heavy duty applications with intense requirements. Read more about industrial dampers in this Newsstand article. These dampers can fulfill any role in an industrial setting: air control, air balancing, backdraft applications, and even round ductwork. Industrial dampers are built from heavy duty materials to withstand immense static pressures and elevated temperatures.

There are a few things to consider when choosing an industrial damper. These dampers will weigh more than a standard damper, so you will need to make sure you have the necessary support. You will also need to make sure the attached actuator has the necessary torque to open and close the damper. Manufacturers can help you make the right choice. Meet industrial requirements with heavy-duty dampers.

Round Dampers – For Spiral Ducts

We’ve covered round dampers before in this article, but it’s worth going over them again. Not all projects have square or rectangular ductwork. Spiral ductwork, or ductwork with a round shape, is common in HVAC. You can install square dampers in these ducts by using transition collars, but this will place the full damper into the airstream. You can use round dampers to improve air performance in these applications.

Round dampers can fulfill many of the same requirements as their square counterparts: airflow control, pressure balancing, backdraft control, and even industrial applications. If you plan to use spiral ducts in your HVAC system, then try adding round dampers.

Multi-zone Dampers – For Air Mixing and Single Unit Projects

Certain projects, like school buildings, will have a single HVAC unit that conditions air for the entire building. The unit will need a way to direct airflow to different classrooms in the building when needed. This is possible with help from a multi-zone damper.

Multi-zone dampers are control dampers that are divided into separate zones, which are typically designated for either warm air or cool air. Damper zones will operate independently so that each zone can open or close on its own. For projects with a single HVAC unit, these zones will direct the required air throughout the building to where it’s needed.

Multi-zone dampers can also be used in mixing zones to combine air before sending it out. HVAC units designed for multiple zones will often come with a multi-zone damper. Manufacturers may offer multi-zone dampers to supplement these installations.

Your project will have its own set of requirements and its own applications. Special applications call for specialty dampers. You should know your options when designing an HVAC system.

For more on dampers, check out these Newsstand articles:

• Four Ways to Make Efficient Dampers
• Options for Control Dampers
• Control versus Balance - The Difference Between Dampers
• Damper Dimensions

Starting a new project and need HVAC dampers? Check out the 517-518 steel control damper from Arrow United Industries. Contact Arrow United and let us help with your HVAC requirements!

MCDLG & Continuing Education

Want to know more? MCDLG offers a free self-paced course on control dampers.  

Learn the basics of control dampers with "An Introduction to Air Control Dampers", including their components, what they do, where they go in an HVAC system, and guidelines for installing and maintaining your control dampers. 

This course provides continuing education credits for a variety of institutions, including ASHRAE's PDUs. Learn and earn at your own pace. Visit the MCDLG Campus Portal today!

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