FIRE PROTECTION & LIFE SAFETY DESIGN MANUAL

Risers shall not be less than 4 inches (10.2 cm) nor more than 7 inches (17.8 cm). Variations in width of tread and height of risers shall not exceed 3/16 inch (.5 cm). Landings . Doors may not open immediately onto stairs without a landing of at least the width of the door, plus one tread dimension. Headroom ................
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