Alternating Tread Device Ibc

More tread depth means a larger stepping surface and greater stability for the user.

Alternating tread device ibc.

Ibc compliant applications for alternating tread stairs include. Ibc requirements for alternating tread stairs 1011 14. 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. If they are to be part of the metal alternating tread stair contractor s work they must be specified here.

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. Access to unoccupied roofs egress from mezzanines under 250 square feet with five or less occupants 1. 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. A device that has a series of steps between 50 and 70 degrees 0 87 and 1 22 rad from horizontal usually attached to a center support rail in an alternating manner so that the user does not have both feet on the same level at the same time.

Alternating tread devices in accordance with section 1009 9. On its own this is a great advantage. Egress from guard towers observation towers and control rooms under 250 square feet 2. 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.

Alternating tread stairs provide the same space saving benefit but more than twice the usable tread depth as a ships ladder or ship stair. The projected tread depth shall be measured horizontally between the vertical planes of the foremost projections of adjacent treads. 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.