How much expansion clearance do I need to leave around a fire damper sleeve?

The rough wall framing opening must be larger than the damper sleeve. The general standard rule of thumb is leaving \frac{1}{8} inch of clearance per linear foot of damper width and height, or a strict minimum of \frac{1}{2} inch total clearance gap around the entire sleeve perimeter, unless specified otherwise by the UL installation listing sheet.

['The rough wall framing opening must be larger than the damper sleeve. The general standard rule of thumb is leaving \\frac{1}{8} inch of clearance per linear foot of damper width and height, or a strict minimum of \\frac{1}{2} inch total clearance gap around the entire sleeve perimeter, unless specified otherwise by the UL installation listing sheet.']

Stop if

• Use this as training guidance. The foreman, approved drawings, project specs, manufacturer installation instructions, employer safety policy, and AHJ/code requirements always control the final answer.

Steps

• Stop and verify the approved detail, manufacturer instructions, foreman direction, and project specs before touching it.
• The rough wall framing opening must be larger than the damper sleeve. The general standard rule of thumb is leaving \frac{1}{8} inch of clearance per linear foot of damper width and...

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