Which enclosure type is required for luminaires installed in ducts or plenums used to transport environmental air?

Which enclosure type is required for luminaires installed in ducts or plenums used to transport environmental air?

• A. Screw-type
• B. Gasketed-type
• C. Plug-type
• D. Neon-type

Answer: (B)

When a light is placed in a duct or plenum that carries environmental air, the fixture must be sealed to prevent air from leaking around it. A gasketed-type enclosure provides a tight seal at the luminaire interface with the duct or plenum, stopping air leakage and helping meet fire/smoke containment requirements in air-handling spaces. The other enclosure types describe configurations that don’t seal the joint, which would allow air to bypass the fixture and undermine the integrity of the ventilation space. So, a gasketed-type enclosure is required.

When a light is placed in a duct or plenum that carries environmental air, the fixture must be sealed to prevent air from leaking around it. A gasketed-type enclosure provides a tight seal at the luminaire interface with the duct or plenum, stopping air leakage and helping meet fire/smoke containment requirements in air-handling spaces. The other enclosure types describe configurations that don’t seal the joint, which would allow air to bypass the fixture and undermine the integrity of the ventilation space. So, a gasketed-type enclosure is required.