Alternating Tread Device Ibc

The initial tread of the device shall begin at the same elevation as the platform landing or floor surface.

Alternating tread device ibc.

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. Egress from guard towers observation towers and control rooms under 250 square feet 2. Ibc compliant applications for alternating tread stairs include.

Alternating tread devices in accordance with section 1009 9. 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. The international building code and nfpa 101 life safety code use the term alternating tread device 1 2 additional work included in this section some items of work are usually specified in sections other than 05 51 33 23. 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.

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 devices and ships ladders are now permitted as a means of egress for lofts with an area that does not exceed 200 square feet. 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. More tread depth means a larger stepping surface and greater stability for the user.

On its own this is a great advantage. Ibc requirements for alternating tread stairs 1011 14. Access to unoccupied roofs egress from mezzanines under 250 square feet with five or less occupants 1.