Significant changes to top of shaft enclosures in the 2021 International Building Code
The 2021 Significant Changes guides are available for the International Building, Residential, Fire, Energy Conservation, Plumbing, Mechanical and Fuel Gas Codes. This valuable series can help any code user save time by zeroing in on the most critical changes in the 2021 International Codes. The Code Council’s technical experts provide summaries, analysis and graphics for these changes making them clear and easy to understand.
2021 International Building Code
A clarification to Section 713.12 (Top of Shaft Enclosure) states that the three options for termination at the top of a shaft enclosure have been clarified.
Revisions shown in Section 713.12 help clarify how the top of a shaft is permitted to be terminated. The format is intended to mirror Section 713.11 for the bottom of the shaft and identify the common termination conditions and their requirements. These three termination conditions already exist in the code, therefore, this revision does not create any technical change to the code requirements. While conditions 1 and 2 are clearly created from existing text, Item 1 now references the Table 601 roof construction provisions. Item 3 points to penthouse provisions in Section 1511. The definition for a penthouse indicates it is “an enclosed, unoccupied rooftop structure used for sheltering… vertical shaft openings.” Adding this third condition provides details for the top of the shaft whether it terminates at, below, or above the roof.
The new Section 713.12.1 recognizes that not every penetration or opening that pierces a roof requires protection. The IBC typically does not address conditions where a fire spreads from the interior of the building to the exterior as illustrated in the acceptance of unprotected roof openings for penetrations (Section 714.5), ducts (Section 717.6), and skylights (Section 712.1.15). Where a mechanical penthouse provides an extension of a shaft enclosure from below, it has been clarified that neither a fire nor smoke damper is required at such penetrations provided all ductwork in the shaft enclosure is directly connected to heating, ventilation and air-conditioning (HVAC) equipment.
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