Tempo:
Stairs provide access between floors, and their configuration, clearances and tread design must meet or exceed NBC requirements to ensure safety during regular use and safe and efficient exiting in the event of fire. Common terms for stairs (Figures 139 to 145) are as follows:
STAIR RISE AND RUN For safety and ease of use, stairs must comply with specific requirements. The rise and the run must be uniform for all treads in a flight of stairs. For stairs in houses, the minimum run for rectangular stairs is 210 mm (8¼ in.), and the maximum is 355 mm (14 in.). The minimum rise is 125 mm (5 in.), and the maximum is 200 mm (8 in.). The minimum tread depth is 235 mm (9¼ in.), and the maximum is 355 mm (1315⁄16 in.).
STAIRWAY DESIGN Stairs may be site built but are most often factory manufactured. Stairways in houses can have a straight, continuous run without an intermediate landing, or consist of two or more runs with changes in direction, or may be curved, in which case special design criteria apply. The minimum allowable stairway headroom is 1.95 m (6 ft. 5 in.) (see Figure 141). The width of any landing must not be less than the width of the stairs. Stairs in houses and houses with a secondary suite must be at least 860 mm (34 in.) wide measured between wall faces. The length of a landing in a house cannot be less than 860 mm (337⁄8 in.). The vertical height of any flight of stairs cannot exceed 3.7 m (12 ft.). Each step in a flight of stairs should have the same height.
STAIR RISE AND RUN For safety and ease of use, stairs must comply with specific requirements. The rise and the run must be uniform for all treads in a flight of stairs. For stairs in houses, the minimum run for rectangular stairs is 210 mm (8¼ in.), and the maximum is 355 mm (14 in.). The minimum rise is 125 mm (5 in.), and the maximum is 200 mm (8 in.). The minimum tread depth is 235 mm (9¼ in.), and the maximum is 355 mm (1315⁄16 in.).
STAIRWAY DESIGN Stairs may be site built but are most often factory manufactured. Stairways in houses can have a straight, continuous run without an intermediate landing, or consist of two or more runs with changes in direction, or may be curved, in which case special design criteria apply. The minimum allowable stairway headroom is 1.95 m (6 ft. 5 in.) (see Figure 141). The width of any landing must not be less than the width of the stairs. Stairs in houses and houses with a secondary suite must be at least 860 mm (34 in.) wide measured between wall faces. The length of a landing in a house cannot be less than 860 mm (337⁄8 in.). The vertical height of any flight of stairs cannot exceed 3.7 m (12 ft.). Each step in a flight of stairs should have the same height.
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