Alternating Tread Stair Building Code Summary

The following condensed codes or proposals address the use of alternating tread stairs in certain applications. The codes themselves and/or local code officials should be consulted for specific requirements. To obtain a copy of any of the following call 1-800-535-7631 or go to Request Additional Information to have it faxed or mailed to you.

U.S. Federal OSHA

OSHA has issued a letter stating that alternating tread stairs are safe, meet the intent of the OSHA Act, and no citations will be issued. This letter can be found on OSHA's website of "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 1-1.11

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 BUILDING CODE 2003

Alternating tread stairs are permitted as a means of egress for the following:

  1. To mezzanines less than 250 sq ft in area and serving five occupants or less in building whose occupancy is F, H or S. (1009.10)
  2. To prison guard towers, control rooms or observation decks less than 250 sq ft in area (1009.10)
  3. To unoccupied roofs. (1009.12)
  4. As one of two means of egress to boiler rooms, incinerator rooms, furnance rooms or refrigeration machinery rooms. (1014.3,4)
  5. To stage catwalks, galleries and gridirons leading to a floor or roof (1014.6.1)

Alternating tread stairs are also permitted for access to equipment platforms as a non means of egress (505)

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 could serve as a secondary stair for convenience purposes.