Alternating Tread Device Ibc

The projected tread depth shall be measured horizontally between the vertical planes of the foremost projections of adjacent treads.

Alternating tread device ibc.

On its own this is a great advantage. Ibc requirements for alternating tread stairs 1011 14. Alternating tread devices in accordance with section 1009 9. Ibc compliant applications for alternating tread stairs include.

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. More tread depth means a larger stepping surface and greater stability for the user. Egress from guard towers observation towers and control rooms under 250 square feet 2. The tread s leading edge.

If they are to be part of the metal alternating tread stair contractor s work they must be specified here. Access to unoccupied roofs egress from mezzanines under 250 square feet with five or less occupants 1. 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 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.

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. 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.