Topic: Dampers
What are the Top Questions Engineers and Contractors Ask about Life-Safety Dampers?
by Michael Bulzomi |

Greenheck manufactures several hundred different damper products. Each offers variations to customize the product to specific applications. This large number of dampers and variations can create a little confusion. We receive many questions regarding life-safety damper products. The following are among the most common, arranged according to the product/application, actuator, or accessories.

Questions on the damper itself vary. Common questions include:

A wall has a fire rating of two hours. Is a 1-1/2-hour rated damper used, or should it be a three-hour rated?
Per the International Building Code (IBC), fire-rated barriers of less than three hours require a 1-1/2 hour rated fire damper. Barriers with a rating for three hours or more require dampers with a three-hour fire rating.

What is the smallest combination fire smoke damper available that can use an internally-mounted electric actuator?
Greenheck can manufacture a combination fire smoke damper that is 8 inches wide by 8 inches high and includes an internal electric actuator.

What is the pressure drop for FSD and SMD dampers?
Each damper has a pressure drop chart listed on its submittal. You may also use the performance calculator available when using the company's product selection software (CAPS®).

Can a combination fire smoke damper be used with a flush-mount grille?
Greenheck does offer out-of-wall combination fire smoke dampers (models OFSD or GFSD) compatible with grilles.

Other damper-related questions focus on installing the damper. For example:

Can a single-sided retaining angle be used on a three-hour rated damper?
No. Single-sided retaining angles are currently only Underwriter's Laboratory (UL) approved for use on 1-1/2 hour rated dampers.


Using the correct actuator on life-safety dampers is critical to the success or failure of dampers during a fire event. Common questions relating to life-safety dampers and actuators vary and include:

Can Smoke and Fire/Smoke Damper actuators be changed in the field?
The short answer is yes. However, the actuator must be UL Listed. The drive arrangement and the number of actuators also must match the damper's UL listing. Proper documentation, cycle testing, and approval of the authority having jurisdiction (AHJ) is advised.

Are 24V DC actuators available for FSD and SMD damper models?
Yes. The Belimo FSLF24 actuator operates on 24V DC and 24V AC power sources. The design of most 24V AC actuators does not allow 24V DC power.


Options and Accessories
Many applications require a custom solution to meet the specifications of the project. Options and accessories frequently offer helpful solutions. Yet, many of these products have similar-sounding names and uses, making selection more difficult for those with less experience. For example:

Does Greenheck manufacture support mullions for field installation on fire dampers?
Greenheck does not make support mullions for field installation on fire dampers, they are field fabricated. It is important to note that support mullions may only be used on static-rated fire dampers. Refer to the Greenheck supplemental IOM for more details.

Are smoke detectors available on Greenheck smoke dampers and combination fire smoke dampers?
Greenheck offers smoke detectors on smoke and combination fire smoke dampers. Smoke detectors can ship mounted or loose.

Is field-mounting possible for open-close indicator (OCI) kits?
You can field mount OCI kits on smoke dampers, provided the unit is more than 11 inches high with an A dimension greater than 10.5 inches. Please consult the factory on combination fire smoke dampers.


Greenheck offers several resources to help with your damper product selection. You can find frequently asked questions (FAQ) on Greenheck's website, which includes some of the questions and responses in this post. The damper FAQ also covers questions about other damper products. However, the best option to get answers to your questions is to contact your local Greenheck representative.

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Michael Bulzomi
Michael Bulzomi
Michael Bulzomi
Michael Bulzomi is product manager for Greenheck commercial dampers. He earned his MBA from Dowling College and his Bachelors in Earth Science and Atmospheric Science from the State University at Albany in New York. A member of ASHRAE, NFPA, and AMCA, he is the current Chair of the AMCA Fire and Smoke Damper Committee.
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