These highly adaptable stairs meet relevant building codes and create a safer work environment.
Alternating tread device width.
Alternating tread stairs provide the same space saving benefit but more than twice the usable tread depth as a ships ladder or ship stair.
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.
International building code ships ladder requirements.
The tread depth shall be measured horizontally between the vertical planes of the foremost projections of adjacent treads.
The code also permits fire escape ladder alternating tread devices and slide escapes in certain occupancies.
Note that ibc code for i 3 spaces calls for 5 minimum.
The tread s leading edge.
Precision s aluminum alternating tread stair is an alternative to a traditional ships stair.
3 means of egress components doors stairs ramps and exit passageways are the most common means of egress components.
Precision ladders at series of aluminum alternating tread stairs were designed with tubular siderails to provide maximum structural integrity while keeping.
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.
The alternating stair requires one unit of space per step.
Minimum depth of 4.
Alternating tread devices shall have a minimum projected tread of 5 inches 127 mm a minimum tread depth of 8 5 inches 216 mm a minimum tread width of 7 inches 178 mm and a maximum riser height of 9 5 inches 241 mm.
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.
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.
The alternating tread stair appears in the image s center with green colored treads.
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.
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.
On its own this is a great advantage.
The projected tread depth shall be measured horizontally between the vertical planes of the foremost projections of adjacent treads.
The image on the right illustrates the space efficiency gained by an alternating tread stair.
Alternating tread devices in accordance with section.
