Wash. Admin. Code § 296-307-26006
Nose or nosing. The part of a tread projecting beyond the face of the riser immediately below.
Open riser. The air space between the treads of stairways without risers.
Platform. An extended step or landing breaking a continuous run of stairs.
Railing. A vertical barrier erected along exposed sides of stairways and platforms to prevent people from falling. The top part of the railing usually serves as a handrail.
Rise. The vertical distance from the top of a tread to the top of the next higher tread.
Riser. The upright part of a step at the back of a lower tread and near the leading edge of the next higher tread.
Stairs or stairway. A series of steps. A series of steps and landings having three or more risers constitutes stairs or a stairway.
Tread. The horizontal part of a step.
Tread run. The horizontal distance from the leading edge of a tread to the leading edge of an adjacent tread.
Tread width. The horizontal distance from front to back of tread, including nosing.
Wash. Admin. Code § 296-307-26006
97-09-013, recodified as § 296-307-26006, filed 4/7/97, effective 4/7/97. Statutory Authority: RCW 49.17.040,[49.17.]050 and [49.17.]060. 96-22-048, § 296-306A-26006, filed 10/31/96, effective 12/1/96.