Corky272
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I'm working on a code review for a new Technical Education Center at a local community college. I'm using the 2021 IBC, and have been stuck in a recursive loop for the last couple of days; I am frustrated and my head hurts.
The building is Group B, F-1, S-1, and H-2. Chapter 5 is where I am hung up. 506.2.2 is a mixed occupancy building (proposed 2 stories); it's less than three stories, so instead of working Equation 5-3, I followed the above directions to Section 508. B, F-1, and S-1 occupancies do not require separation, but H-2 does. That's easy to understand. Following 508.3.2 et al paragraphs in Section 508, I am directed back to 503.1 to figure out my allowable areas. 503.1 says to follow Section 506. What? Enter recursive loop...
Regrouping, and realizing that Equations 5-1 and 5-3 are the same, I decided to move on and figure out my frontage increase. Working through Section 506.3, the 2021 code no longer uses Equations 5-4 or 5-5, instead replacing them with a table based on the smallest public way of 20 feet or greater. This is ambiguous, though: is the percentage of my building perimeter calculated on just the wall that meets that 20 foot requirement, or the length of the entire façade? And then I noticed a new section: 506.3.3.1 Section 507 buildings.
Following Section 507, I discovered Section 507.5 Two-story buildings. HEY!! A two-story B, F, or S building has an unlimited area with restrictions for separated H-2 occupancies. Okay, great! I'm allowed unlimited areas. But now I have a new question: Table 506.3.3.1 in Section 506. If the code allows for a building to have an unlimited area, why does it need a frontage increase? And, if an allowable area determination is required (in spite of 507), which path do I follow for a 2-story mixed occupancy building?
The building is Group B, F-1, S-1, and H-2. Chapter 5 is where I am hung up. 506.2.2 is a mixed occupancy building (proposed 2 stories); it's less than three stories, so instead of working Equation 5-3, I followed the above directions to Section 508. B, F-1, and S-1 occupancies do not require separation, but H-2 does. That's easy to understand. Following 508.3.2 et al paragraphs in Section 508, I am directed back to 503.1 to figure out my allowable areas. 503.1 says to follow Section 506. What? Enter recursive loop...
Regrouping, and realizing that Equations 5-1 and 5-3 are the same, I decided to move on and figure out my frontage increase. Working through Section 506.3, the 2021 code no longer uses Equations 5-4 or 5-5, instead replacing them with a table based on the smallest public way of 20 feet or greater. This is ambiguous, though: is the percentage of my building perimeter calculated on just the wall that meets that 20 foot requirement, or the length of the entire façade? And then I noticed a new section: 506.3.3.1 Section 507 buildings.
Following Section 507, I discovered Section 507.5 Two-story buildings. HEY!! A two-story B, F, or S building has an unlimited area with restrictions for separated H-2 occupancies. Okay, great! I'm allowed unlimited areas. But now I have a new question: Table 506.3.3.1 in Section 506. If the code allows for a building to have an unlimited area, why does it need a frontage increase? And, if an allowable area determination is required (in spite of 507), which path do I follow for a 2-story mixed occupancy building?
