The Condenser - Frame Depth for Louvers and Dampers

How does frame depth factor into louver and damper design? What does it mean for your HVAC project? Learn the basics of frame depth with this quick Condenser article.

You measure louvers and dampers by width and height, while you measure round dampers by their radius. These measurements account for the sides of the unit, which is important for determining whether it will fit in an opening.

You can learn more about proper sizing of dampers in “Damper Dimensions”. The third dimension, depth, is usually accounted for by the model.

An illustration of a damper illustrating three dimensions: width, height, and depth

Frame depth refers to the depth of the unit’s frame, expressed in inches. This is important to know when determining the amount of clearance required at the installation point. When installing in an opening, the substrate should be able to hold the unit’s frame in place.

For more on louvers and dampers, check out these Newsstand articles:

Frame Depth for Louvers

There are ways to support louvers and dampers in an opening if they run deeper than the opening substrate. For in-duct installation, you want the damper to have adequate space to operate. The damper should be able to open and close without interfering with other duct equipment.

Louver types and their common frame depths

For louvers, the model’s description will often include the frame depth, which varies from model to model. Frame depth for most louvers is between two inches and six inches, although thin line louvers can have a half inch depth.

There are many ways to install a louver, though certain louvers will have additional installation requirements. For a flush installation, or for installing a severe weather louver, the louver’s depth should closely match the depth of the opening substrate.

Severe weather louvers will have similar depths to standard louvers, although certain severe duty louvers can have an eight-inch frame depth. The depth of a severe weather louver should closely match the depth of the substrate. Acoustical louvers will have the longest depths of any louver, being anywhere between eight and twelve inches deep. The exact frame depth will depend on the louver model.

Frame Depth for Dampers

Damper types and their typical frame depths

Control dampers and balancing dampers typically have a frame depth between four and six inches. Like louvers, the depth of the frame depends on the damper model. Industrial dampers are the largest damper type, with frame depths up to ten inches deep.

These dampers will require extra support when installed. Measure back draft dampers by their full depth to account for clearance, which goes from the face of the damper to the edge of the blade behind the damper while it is fully open.

This helps determine the amount of clearance needed for the damper. While the frame of the backdraft damper may be four inches deep, the actual depth will be around ten inches to account for the blades. Round dampers are between 6.5 and 7.5 inches deep to give adequate clearance for the blade.

A damper with a frame depths of 5.5 inches

Life safety dampers will have frame depths of between four and six inches, like control dampers. However, you will need to account for the damper’s sleeve, which adds to the overall depth of the unit.

Manufacturers may offer different frames for a particular unit with varying depths. Be sure to read the “Options” section of the submittal for details. Make sure your louvers and dampers fit into your project. Check the unit’s frame depth to determine if it has enough clearance.

Three dampers in front of a blueprint