Core TradesQuestion 35 of 700
Flexible air ducts must be supported at MAXIMUM intervals of about what distance to prevent excessive sagging?
a.18 inches
b.3 feet
c.4 feet
d.10 feet
Explanation
Flexible duct is typically supported at intervals not exceeding about 4 feet, limiting sag to roughly a half-inch per foot between supports. Closer spacing is unnecessary and 10 feet would allow excessive sag that restricts airflow.
Law Reference: 2025 CA Mechanical Code (CMC) §603 (Air Ducts)Practice all 700 questions free — no signup required.
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