Building Planning
Domain focus
Building Planning tests occupancy classification, type of construction, allowable height and area, mixed occupancies, mezzanines, and incidental uses. The exam asks you to look at a use and determine the controlling occupancy group, then apply Chapter 5 limits and Chapter 6 construction type.
Core rules
- Chapter 3 assigns occupancy groups: A, B, E, F, H, I, M, R, S, and U; accessory occupancies are limited by §508.2.
- Chapter 5 controls height in stories and feet, and allowable area per story from Table 506.2.
- Area increases include frontage under §506.3 and automatic sprinkler increases where permitted; do not stack increases incorrectly.
- Mixed occupancies may be separated under §508.3 or nonseparated under §508.4; each method has different fire-resistance requirements.
- Mezzanines under §505 may be exempt from floor area in limited cases but still count for egress and occupant load.
- Incidental uses under §509 must be separated from the main occupancy as listed.
Worked example
A 3-story, Type IIB building contains 40,000 sf of Group B office and 10,000 sf of Group S-2 parking. The designer wants a nonseparated mixed occupancy. Under §508.4, each occupancy must comply with the allowable area and height for its group as if it were a separate building, with the most restrictive height governing. Because Group S-2 parking is 20% of the total area, it cannot be treated as an accessory use, which is limited to 10% of the story area. The designer must document compliance for both groups. A separated design would instead require the listed fire barrier between occupancies.
Traps
Classify by actual use, not by the tenant's name or the shell permit. Do not ignore mezzanine area in occupant load. Do not assume a sprinkler increase applies to every construction type or occupancy. Do not overlook the frontage limitation: frontage must be on a street or approved open space.