Single Stair, Travel Distance, and Accessible Route in a Converted Warehouse
An existing 4-storey warehouse (each floor 1,800 m², 4.0 m floor-to-floor) is being converted to offices. The architect proposes one enclosed exit stair at the north end. The farthest point on each floor is 52 m from the stair door measured along the path of travel, and the floor has a single exit. The building will have 210 occupants per floor. The architect argues that because the building will be sprinklered, the travel distance limit is relaxed and a single exit is acceptable. The accessible route from the street enters at the south end and must cross the full 60 m length of the ground floor to reach the stair and elevator lobby. The elevator lobby is 1.5 m wide.
1. Evaluate the single-exit and travel-distance proposal. Is sprinklering sufficient justification?
Read the worked answer
Sprinklering does not by itself permit a single exit or unlimited travel distance.
Evaluation:
- With 210 occupants per floor and four storeys, the occupant load and building height generally require at least two exits. A single exit is permitted only within strict limits on occupant load, travel distance, and storey height, which this building exceeds.
- The 52 m travel distance must be compared to the code limit for the occupancy and sprinkler status. Even where sprinklers extend travel distance, the single-exit condition is the controlling issue.
- The correct fix is a second enclosed stair at the south end, which also shortens travel distance and provides redundancy if one stair is blocked.
Conclusion: the proposal is deficient; require a second exit stair.
2. Assess the accessible route and elevator lobby width, and state what must change.
Read the worked answer
Issues:
- The accessible route crosses 60 m of ground floor to reach the elevator; that is acceptable in length if it is continuous, at least 1.2 m clear width, and free of obstructions, but it must be evaluated for slope and door clearances.
- The elevator lobby at 1.5 m wide is marginal; it must provide the required clear space in front of the elevator doors and allow a wheelchair to turn and wait without blocking the route. A 1.5 m width may not satisfy the turning and door-clearance requirements depending on door swing and configuration.
- If a second stair is added at the south end, the accessible route should be coordinated with it so the path is direct.
Required changes: widen the elevator lobby or reconfigure door swings to provide compliant clear space, and confirm the entire route meets width, slope, and door-clearance criteria.