Means of Egress and Accessibility
The egress sequence
The egress path is exit access → exit → exit discharge. Compute occupant load first (Table 1004.5), then width, then number of exits, then arrangement. Common factors: assembly concentrated 5 net, unconcentrated 15 net, standing space 5 net, business 150 gross, mercantile 60 gross, educational 50 net, residential 200 gross, storage 300 gross, industrial 200 gross.
Width and exits
Table 1005.3.2 provides capacity in inches per occupant: 0.2 in for corridors, ramps and doors (0.15 in where sprinklered) and 0.3 in for stairs (0.2 in where sprinklered). Minimums still govern - 32-inch clear door width, 44-inch corridors in most cases. Number of exits follows Table 1006.3.3; one exit is commonly permitted up to 49 occupants. Travel distance (Table 1017.2) for Group B is 200 feet unsprinklered and 300 feet sprinklered. Common path of travel and dead-end corridor limits are separate checks, as are stair geometry (7-inch riser, 11-inch tread, handrails 34–38 inches, 42-inch guards).
Accessibility
Chapter 11 and ICC A117.1 govern: accessible routes 36 inches wide, 30-by-48-inch clear floor space, 60-inch turning space, reach ranges roughly 15–48 inches, ramp slope maximum 1:12 with a 30-inch rise per run and landings at top, bottom and turns.
Worked example
A sprinklered Group B floor with 200 occupants: corridor width = 200 × 0.15 = 30 inches, but the 44-inch minimum governs; stair width = 200 × 0.2 = 40 inches, still subject to minimum stair width. Widths are summed across the means of egress serving that load, and each occupant is counted once.
Traps
Net versus gross occupant load factors, applying capacity factors to the wrong component, and forgetting that minimum widths override calculated widths.