3.1003.5 Dropped Ceiling with Light Boxes and Fixtures

Topic: 
Attics
Subtopic: 
Dropped Ceilings and Soffits
Desired Outcome: 
Sealed light boxes safely prevent air leakage and moisture movement between the attic and conditioned space
TitleSpecification(s)Objective(s)
3.1003.5a
Pre-inspection

An inspection will be conducted for mold, water leaks, and water damage before sealing a dropped ceiling or soffit

Repairs will be completed before work begins

Repair moisture-related issues

3.1003.5b
Light boxes (e.g., fluorescent lights)

An airtight seal will be provided around perimeter between light box enclosure and interior ceiling

All seams and penetrations of the enclosure will be sealed

Access will be gained as needed (e.g., pull flooring)

Seals will be used that prevent visible air movement using chemical smoke at 50 pascals of pressure difference

Prevent air leakage

3.1003.5c
Non-insulation contact ( IC IC Insulation contact ) rated recessed lights

Insulation will be kept at least 3 inches away from the top and side of any fixtures

If dropped ceiling is to be filled with insulation, then a sealed rigid barrier enclosure will be installed to maintain a 3 inches clearance on all sides

Top of rigid barrier enclosure will be sealed with non-insulating rigid material Rigid material Drywall, oriented strand board, duct board, cardboard, or any other stiff product that may support the load of insulation while serving as a durable air barrier (e.g., gypsum or equivalent perm rating Perm rating The measurement of a material's ability to allow the transfer of water vapor through the material and R-value)

Prevent light fixture from overheating

Bring light fixture inside of the air barrier Air barrier The separation between the interior and exterior environments of a building that slows air flow to the point that no smoke movement is visible at 50 pascals of pressure difference across the boundary