Does an Occupied Roof Trigger High-Rise Requirements?

This week, the ICC Committee Action Hearings (CAH) kicked off, where proposed code changes for the 2024 ICC Codes are heard by the various ICC committees. In yestereday's session, the IBC General committee heard several proposed changes related to occupied roofs and the classification of high-rise buildings. In recent code cycles, there have been several key changes to occupied roof requirements, but none of these have addressed whether an occupied roof over 75' would trigger classification of a high-rise building.

As a quick reminder, the 2021 IBC currently defines a high-rise building as "A building with an occupied floor located more than 75 feet above the lowest level of fire department vehicle access."

If the current proposed code change moves forward, an occupied roof like this one could trigger classification as a high-rise building.

While previous code editions have remained silent on the issue, the ICC website does have two articles addressing high rise classification due to an occupied roof.

This article, authored by ICC staff member Chris Reeves, clearly states that an occupied roof is not intended to count as a floor for the purposes of evaluating the high-rise building definition. Another article, authored by ICC staff member Kimberly Paarlberg, states "What has not yet been clarified is if an occupied roof is considered an occupied floor when determining if the building does or does not have to meet the high-rise provisions in the code..."

While the two articles above are both informal opinions from ICC staff, it appears the 2024 IBC will now address this issue directly. During today's hearing, the IBC General Committee voted in favor of proposal G15-21, which is copied below:

Revise as follows:
[BG] HIGH-RISE BUILDING. A building with an occupied floor or occupied roof located more than 75 feet (22 860 mm) above the lowest level of fire department vehicle access.

This proposed change to the definition of a high-rise building would require any building with an occupied roof above 75' to meet all of the high-rise building requirements.  Several proposals, including G12-21 and G14-21, were aimed the other way, attempting to clarify that an occupied roof would not trigger a high-rise classification. Both of these were disapproved by the committee.

When a building is classified as a high-rise, there are numerous additional requirements, including:

• Hard Body Impact requirements for stairway and hoistway walls in Risk Category III and IV buildings (IBC 403.2.3)
• Minimum SFRM bond strength of 430 psf (up to 1,000 psf for buildings higher than 420') (IBC 403.2.4)
• Voice fire alarm system (IBC 403.4.4)
• Fire command center (IBC 403.4.6)
• Smoke removal (IBC 406.4.7)
• Additional standby and emergency power requirements (403.4.8)
• Smokeproof enclosures (most commonly stair pressurization) for exit stairways (IBC 403.5.4)

What Do You Think?

Do you agree with the General Committee on this issue? Should an occupied roof above 75' trigger the classification as a high rise building? Please share your thoughts in the comments section!

If you disagree with this viewpoint, there is still time to have your opinion heard before the change is codified. The ICC code development process includes a public comment period, which will be open between May 24 and July 2. Any one is free to submit a comment on this issue or any other proposed changes moved forward by ICC committees. The ICC Public Comment Hearings (PCH) will take place between September 22-29 in Pittsburgh (also open to the public).