The 70-Seat Training Room in a Single-Stair Office Floor
A design firm is planning an 8,400 sq ft tenant fit-out on the fourth floor of a fully sprinklered downtown office building. The floor has two existing exit stairs, and the farthest point of the open office is 210 ft from the nearest stair. The client, a software company, wants a 900 sq ft training room with 70 fixed chairs, a 1,200 sq ft employee cafe, and open workstations for 55 staff. The base-building architect confirms that corridors and stairs are existing and will not be modified. During preliminary code review, the contractor's permit expediter remarks that the training room 'should be fine because it is under 1,000 sq ft and the chairs are movable.' The training room has one 36 in. door opening into the main corridor near the elevator lobby, 8 ft from a corridor intersection. The client has already ordered 70 chairs and scheduled quarterly all-hands meetings.
1. May the training room be treated as an accessory occupancy to the business use? State your determination and the consequences that follow from it.
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Test the accessory-occupancy criteria, not the expediter's rule of thumb.
- Area test. 900 sq ft ÷ 8,400 sq ft = 10.7%. Under the accessory provisions of the adopted code, the aggregate accessory area on a story is generally capped at 10% of the story area (confirm the local edition). The room fails this test.
- Occupant-load test. Assembly-type spaces used by fewer than 50 occupants are commonly permitted to be classified with the main occupancy. At 70 seats the room exceeds that threshold, so it cannot ride along as business use.
- Result. The room must be classified as an assembly occupancy (A-3 in most editions). That triggers a separate review of required occupancy separation from the B occupancy, exit access and exit discharge from the room itself, and the interior finish requirements for the room and its exit access path. It also means the cafe cannot be lumped in as an offsetting 'accessory' to cure the area overage - employee break rooms within a B suite are ordinarily classified as part of the business use regardless of area.
Response to the expediter. 'Under 1,000 sq ft' and 'movable chairs' are not code criteria; fixed seating is not required for a space to be an assembly occupancy. Document the classification decision in the code analysis page of the permit set so the reviewer and the client see the same logic, and note that the classification changes the finish and egress requirements the client is about to buy furniture for.
2. Evaluate the egress adequacy of the 70-seat configuration and state what you would recommend to the client.
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Width is not the problem; the number of exits is.
- Capacity of the door. A 36 in. door provides roughly 32 in. of clear width. At 0.2 in. per occupant for egress capacity, one door could carry about 160 occupants, well above 70.
- Number of exits. At 70 occupants the room exceeds the occupant threshold at which a single exit is permitted, so two means of egress from the room are required. The existing 36 in. door is one.
- Travel distance in the suite. 210 ft to the nearest stair is within the 250 ft limit for a sprinklered business occupancy, so the floor's overall egress is not the issue.
- Options, in order of practicality:
- Cut the seat count to 49 and confirm the actual room occupant load computation supports it; this preserves the single-door condition and is the cheapest fix.
- Add a second exit door to the room on a different wall, remote from the first door by at least half the diagonal of the room, discharging either to the corridor or directly to a stair.
- Relocate the training function to a floor or room that already has two remote exits.
Present the seat reduction as a program decision with cost and schedule attached, not as an abstract code note - the client has already bought 70 chairs, so the cost of the second door and any corridor reconfiguration should be estimated before the meeting.
3. The client proposes keeping 70 seats and adding a second door two feet from the existing door, on the same wall. Evaluate that proposal.
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Reject it as designed, and explain why in egress terms rather than as an opinion.
- Remoteness. Exits must be separated by a distance of not less than half the overall diagonal of the room, measured between the nearest edges of the doorways. Two doors 2 ft apart on the same wall are not remote from one another; for egress purposes they behave as a single exit, so the second door provides no additional means of egress.
- Door swing. At this occupant load, doors must swing in the direction of egress travel and be equipped with panic hardware. A second door added near the first compounds congestion at the same corner of the room rather than relieving it.
- Corridor impact. Both doors would discharge within 8 ft of the same corridor intersection, concentrating 70 occupants into one point of the corridor and potentially creating a dead-end or blockage condition where occupants turn toward the stair.
- Acceptable alternatives. Place the second door on the opposite or adjacent wall so remoteness is satisfied, or reduce the seat count. If the client resists, model the room's occupant flow on the floor plan and show the convergence point - a diagram settles this argument faster than a code citation.
Get the client's decision in writing and revise the egress plan and the door schedule together so the hardware and swing direction do not get value-engineered out later.