Alternating Tread Stair Building Code Summary
The following condensed codes/proposals address the use of the alternating tread stairs in certain applications. Actual codes and/or local code officials should be consulted for specific requirements and compliance. See our code compliance for more information. Contact us to request copies.
U.S. Federal OSHA
OSHA has issued a letter stating that the alternating tread stair "is safe for use, meets the intent of the Occupational Safety and Health Act and no citations will be issued if it is properly installed and maintained per your specifications." This letter can be found on OSHA's website: Standards Interpretation and Compliance Letters.
In April 1982, OSHA issued a directive to field compliance officers concerning the use of alternating tread stairs. This directive can also be found on OSHA's website: Instruction STD 11.11
OSHA's proposed revision of industry standards for workplace walking and working surfaces (29 CFR part 1910) addresses alternating tread stairs (Section 1910.25, of Federal Register / Vol. 55, No. 69 / April 10, 1990 / Proposed Rules). The proposed rule is still outstanding and was re-opened in May 2003. You may view the status of this rule and the full document on their website under Walking and Working Surfaces; Personal Protective Equipment (Fall Protection Systems) - 68:23527-23568
International Bulding Code 2003
Alternating tread stairs are permitted as a means of egress for the following:
- To mezzanines less than 250 sq ft in area and serving five occupants or less in buildingwhose occupancy is F, H or S. (1009.10)
- To prison guard towers, control rooms or observation decks less than 250 sq ft in area (1009.10)
- To unoccupied roofs. (1009.12)
- As one of two means of egress to boiler rooms, incinerator rooms, furnace rooms or refrigeration machinery rooms. (1014.3,4)
- To stage catwalks, galleries and gridirons leading to a floor or roof (1014.6.1)
SBCCI Standard Building Code
The 1994 edition of the Standard Building Code permits alternating tread stairs with a minimum projected tread of 8.5 inches to access 250 square foot mezzanines or less, occupied by no more than 5 people. They may also be used to and between staff locations in penal facilities. (Section 1007.8)
BOCA National Building Code
The 1999 National Building Code permits alternating tread stairs with a minimum projected tread of 5 inches and a minimum tread depth of 8.5 inches as a means of egress from mezzanines, roofs and various areas in penal facilities; exception as a means of egress from a mezzanine area not more than 250 sq. ft. not serving more than 5 occupants, shall have a minimum projected tread of 8.5 inches, minimum tread depth of 10.5 inches. (Section 1014.6.6 and 1027.0)
ICBO Uniform Building Code
An October 1987 letter states that the alternating tread stair may be installed when it is used only to attend equipment. (Section 3306 (a))
U.S. Coast Guard
In September 1984, the U.S. Coast Guard issued a letter addressing the use of alternating tread stairs and the authorized locations of inspected vessels. (Document #16711)
Canadian Ministry of Housing
A November 1988 letter states that alternating tread stairs may serve as a secondary stair for convenience purposes.