Welcome back to the 10th Edition Major Changes blog series! This post discusses miscellaneous code changes related to occupied roofs, including provisions on occupancy classification, penthouse definitions, and door locking provisions.
The acknowledgment of occupied roofs was introduced in the 2018 edition of the International Building Code (IBC) due to the industry call for life safety requirements for rooftop amenity spaces that are open to building occupants or the general public. These spaces often include areas such as rooftop swimming pools and lounge decks.
New to the code are the conditions under which certain rooftop occupancy classifications are allowed, which is interrelated to building fire protection systems, construction type, and height and area allowances. The rooftop space is required to be classified based on the use (e.g. Group A-3 for larger assembly spaces). The allowance of such an occupancy is dictated by the following two conditions:
- If the building is non-sprinklered, the occupancy of the roof deck is limited to that which complies with Allowable Height table for the story below, OR
- If the building is sprinklered (and the area of the occupied roof is provided with an occupant notification system), any occupancy classification is allowed for the space.
Note that, in either scenario, the occupied roof is not required to be included in the height and area determination. The occupied roof is required to meet the other applicable occupancy provisions of the code.
Penthouse vs. Story
The difference between whether a rooftop structure can be defined as a penthouse vs. an additional building story, which has implications on height and area calculations, depends on the definition and allowable uses of a penthouse in IBC Chapter 15. Related to occupied roofs, the new code will clarify that ancillary spaces used to access elevators and stairways (i.e. enclosed lobbies) still fall within the definition of a penthouse and do not trigger the classification as an additional story. Otherwise, penthouses continue to be limited to use for purposes of shelter of mechanical or electrical equipment, tanks, elevators and related machinery, stairways, and vertical shaft openings in the roof assembly.
Door locking for terrace and rooftop spaces was not previously addressed in the code. To address concerns for security, IBC Section 1010.2.4(8) now permits exit access doors from most exterior spaces to be equipped with an approved locking device, provided that certain features are provided including items such as signage, a two-way communication system, and glazing in the door. These provisions will assist with overall security of the building while still accounting for egress and life safety.
Thanks for tuning in to this week’s 10th Edition blog post. It’s important to highlight that the 10th edition of 780 CMR has not been finalized or adopted in Massachusetts and is potentially subject to further changes. Our current projection for the adoption of the 10th edition is Q2 of 2024 – see our prior post which outlines the overall process and timeline.
Stay connected for more Insights posts as we continue our “10th Edition Major Changes” series as part of CRC’s 10th Anniversary!