WAC 296-24-74025. Ship stairs

In addition to WAC 296-24-74005 , you must also ensure ship stairs (see Figure D-9 of this section): (1) Are installed at a slope of 50 to 70 degrees from the horizontal; (2) Have open risers with a vertical rise between tread surfaces of 6.5 to 12 inches (17 to 30 cm); (3) Have minimum tread depth of 4 inches (10 cm); and (4) Have a minimum tread width of 18 inches (46 cm). Figure D-9 - Ship Stairs