Smoke dampers are not required in corridor penetrations if the duct is made of steel of what minimum thickness?

Smoke dampers are critical components in HVAC systems, primarily serving to prevent smoke from traveling through ductwork in the event of a fire. However, there are exceptions to the requirement for smoke dampers based on the materials and thickness of the ducts used in corridor penetrations.

In this particular question, the specific minimum thickness of steel duct that negates the need for smoke dampers is crucial. A thickness of 0.019 inch is the standard that allows for this exemption. Ductwork constructed from steel at this minimum thickness is considered sufficiently durable to resist the passage of smoke without the added requirement of a smoke damper. This regulatory guideline helps ensure fire safety while allowing for flexibility in duct design.

The other thicknesses listed, such as 0.19 inch, 0.0019 inch, and 1.9 inches, either exceed the typical requirements or fall below the necessary standard, thus necessitating the use of smoke dampers. Understanding the requirements around duct material and thickness is essential for compliance with safety codes and effective HVAC system design.