Alternating Tread Device Width

The tread s leading edge.

Alternating tread device width.

International building code ships ladder requirements. The code also permits fire escape ladder alternating tread devices and slide escapes in certain occupancies. These stairs allow the user to descend face forward giving a clear view of the floor below. Precision s aluminum alternating tread stair is an alternative to a traditional ships stair.

Winder treads shall have a minimum tread depth of 11 inches 279 mm measured at a right angle to the tread s leading edge at a point 12 inches 305 mm from the side where the treads are narrower and a minimum tread depth of 10 inches 254 mm. Clarification r312 1 r312 1 guards the guard requirements only apply to the specific portion of a walking surface that exceeds 30 inches above grade. Note that ibc code for i 3 spaces calls for 5 minimum. The image on the right illustrates the space efficiency gained by an alternating tread stair.

Alternating tread devices in accordance with section. These highly adaptable stairs meet relevant building codes and create a safer work environment. Alternating tread stairs provide the same space saving benefit but more than twice the usable tread depth as a ships ladder or ship stair. More tread depth means a larger stepping surface and greater stability for the user.

The same as the half width step on its left and half as much as the full width stair on its right. Alternating tread devices and ships ladders alternating tread devices and ships ladders are now permitted as a means of egress for lofts with an area that does not exceed 200 square feet. Reduce design time construction costs and installation errors with pre engineered stairs from lapeyre stair. The tread depth shall be measured horizontally between the vertical planes of the foremost projections of adjacent treads.

Minimum depth of 4. Alternating tread devices shall have a tread depth of not less than 5 inches a projected tread depth of not less than 8 1 2 inches a tread width of not less than 7 inches and a riser height of not more than 9 1 2 inches. On its own this is a great advantage. The alternating tread stair appears in the image s center with green colored treads.

The clear width should be at least 18 wide. Precision ladders at series of aluminum alternating tread stairs were designed with tubular siderails to provide maximum structural integrity while keeping. The alternating stair requires one unit of space per step. According to the international building code 2018 ship ladders cannot be used as a means of egress with one exception the exception per ibc 2018 1011.