A Type IIA building uses conventional non-heavy-timber roof construction. No Table 601 footnote exception or other rating modification applies. Under 2021 IBC Table 601, what minimum fire-resistance rating applies to the roof construction and its associated secondary structural members?
- A0 hours
- 1 hour
- C2 hours
- D3 hours
Where to look it up
https://core-docs.s3.amazonaws.com/documents/asset/uploaded_file/3836/Lennox/3042180/2021_International_Building_Code.pdf
Why B is correct
The roof-construction row in the Type IIA column specifies 1 hour. Footnote exceptions are excluded by the question. A commercial-use label alone does not prescribe a universal two-hour roof rating, and a higher rating is not automatically noncompliant. Source: 2021 IBC Table 601, p. 6-1; https://core-docs.s3.amazonaws.com/documents/asset/uploaded_file/3836/Lennox/3042180/2021_International_Building_Code.pdf