What code specifies that no notch may be located where the joist section exceeds 4 feet in the middle?

The correct code that specifies notching restrictions related to joist sections exceeding 4 feet in the middle is detailed in IMC 302.3. This provision outlines critical guidelines for ensuring structural integrity and safety during HVAC installations.

When joists are notched, especially at critical load-bearing points, it can significantly impact their strength and performance. Allowing notches in areas where there is a span of more than 4 feet without proper guidelines can lead to structural failure, which is why this code is in place. By prohibiting notches in these specific areas, this code helps to maintain the overall stability of the building while accommodating HVAC systems.

Understanding these codes is essential for HVAC professionals as they help ensure that installations comply with legal standards, promote safety, and protect structural integrity.