A contractor is designing a duct system for a new residential building. The total length of the supply duct is 100 feet. According to the 2024 International Residential Code, what is the maximum allowable friction loss for this duct?
- A0.10 inches of water per 100 feet of duct.
- 0.15 inches of water per 100 feet of duct.
- C0.20 inches of water per 100 feet of duct.
- D0.25 inches of water per 100 feet of duct.
Exam tip
Be familiar with the maximum allowable friction loss for different types of ducts.
Why B is correct
Section M1503.5 of the 2024 IRC states that the maximum allowable friction loss for supply ducts is 0.15 inches of water per 100 feet of duct.