Four Stories, One Stair, One Stage
An existing four-story 1968 building is being renovated into a mixed-occupancy project. The ground floor of 1,400 m² contains a 300-seat assembly space (A-3), a 40-occupant retail shop (M), and a business lobby (B). Floors 2–4 are 1,400 m² each of open office (B). The building is fully sprinklered, has one enclosed 1.2 m wide stair, and had a second stair removed in 1995 to gain floor area. The longest travel path from the fourth floor to the remaining stair is 82 m. The client wants a 600 mm high accessible stage platform in the assembly space, reached by a 1:8 ramp the contractor calls "grandfathered." A new elevator opens onto a 1,100 mm wide corridor with a 750 mm clear door. The AHJ has asked for a code analysis before permit.
1. Assess egress for the building and identify the controlling deficiencies using occupant loads.
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Start with occupant load, because it drives everything else.
Occupant load: assembly 300 (fixed seats); retail 40; office floors at 1,400 ÷ 9.3 ≈ 150 per floor. The fourth floor is therefore about 150 occupants.
Number of exits: where the occupant load of a floor or space exceeds 49, at least two means of egress are required, and they must be remote from each other. A 150-occupant office floor with one stair fails on count regardless of width. The assembly space at 300 occupants also requires two exits, and the 1,200 mm stair provides only 1,200 ÷ 7.6 ≈ 158 occupants of stair capacity - insufficient for either the fourth floor alone or the assembly floor, which needs 300 × 5 mm = 1,500 mm of level egress width before any other ground-floor occupants are counted.
Travel distance: 82 m is within the 90 m permitted for sprinklered business occupancy, but assembly is limited to 75 m, and a single stair creates an excessive common path of travel.
Controlling deficiencies: the missing second stair, and the assembly egress width. Options are restoring the second stair, adding an exterior stair, or reducing floor occupant loads so each floor legitimately qualifies for a single exit - the last is rarely acceptable to an owner and must be documented as an occupancy limit on the certificate.
2. Address the accessibility items: the 1:8 ramp, the 1,100 mm corridor, and the 750 mm door.
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None of these are grandfathered in a renovation of this scope.
The ramp: 1:8 is steeper than the 1:12 maximum for a ramp; a 1:8 ramp is only acceptable as a short curb transition, not for a 600 mm rise. At 1:12, a 600 mm rise needs 7.2 m of run plus landings at the top and bottom and intermediate landings - about 9 m of floor length. If that does not fit, a platform lift is the usual alternative, with the caveat that lifts need maintenance contracts and emergency communication. "Grandfathered" is wrong because an alteration that affects accessibility triggers an upgrade obligation for the altered area and its path of travel.
The corridor: 1,100 mm is below the 1,120 mm minimum for a corridor serving an occupant load of 50 or more under the building code, and below the 1,200 mm often required for a wheelchair to turn and pass in a healthcare-adjacent path. It must be widened or the adjacent rooms reconfigured.
The door: 750 mm clear is below the 815 mm clear required. Rehang or replace the frame and door; do not accept the contractor's field measurement without verifying the clear width with the door open at 90°.
Present this as a single accessibility deficiency list with locations, so the contractor prices one scope rather than three change orders.