A satellite antenna mast is proposed to be fastened to a plumbing vent terminal above a roof. Under unamended 2021 IPC Section 903.4, is that additional use permitted?
- AYes, if the mast is electrically bonded
- No; the terminal may only be used as a vent terminal
- CYes, if the vent is at least 3 inches in diameter
- DYes, if the antenna is within 12 inches of the roof
Where to look it up
https://www.ncosfm.gov/b-1-2024-ncpc/open
Why B is correct
The 2021 model rule limits the terminal to its vent function. It does not provide the original answer’s approved-anchorage exception; that wording appears as an NC addition in the comparison and must not be presented as the unamended IPC rule. Bonding, pipe diameter and low mounting height do not establish permission under this provision. See PDF p.125, Section 903.4 base sentence. Source: 2021 IPC model-code base text reproduced in NC OSFM comparison document (not a claim about proposed or adopted NC amendments), https://www.ncosfm.gov/b-1-2024-ncpc/open