OSHA & IBC Mezzanine Code Requirements for Egress Stairs

Mezzanine stair requirements depend on the type and use of the mezzanine being accessed. A mezzanine means of egress is required for most mezzanine structures unless the mezzanine is used only as an equipment platform.   Mezzanine access stairs must be either IBC-compliant stairs or OSHA-compliant stairs.

What are mezzanine stairs?

To answer those questions, it first helps to understand the mezzanine definition. According to IBC, a mezzanine is an intermediate level or levels between the floor and ceiling of any story and in accordance with Section 505. Section 505.2 states that a mezzanine shall be considered a portion of the story below. So a mezzanine is considered a permanent part of the building which must comply with Chapter 10 Means of Egress, and any stairways to access the mezzanine will need to be IBC compliant. What gets confusing is the difference between an equipment platform and vs mezzanine. IBC defines an equipment platform as an unoccupied, elevated platform used exclusively for mechanical systems or industrial process equipment, including the associated elevated walkways, stairways, alternating tread devices, and ladders necessary to access the platform. Unlike a mezzanine, an equipment platform is not considered a portion of the floor below, and the stairways, alternating tread devices, and ladders providing access to an equipment platform shall not serve as a part of the means of egress from the building. So stairways to equipment platforms will typically need to comply only with the OSHA stair requirements.

Determine if mezzanine code requirements apply

The first question to ask is always what is the use of the structure? If it is strictly for equipment or mechanical systems, then it is likely an equipment platform or a catwalk and must comply with the OSHA catwalk requirements.  If any other use, it is a mezzanine that must have IBC-compliant industrial stairs to access. IBC industrial stairs are pictured below.

Mezzanine Egress Requirements

The mezzanine egress requirements are found in IBC Section 10 Means of Egress. Under section 1006, mezzanines must be provided by a means of egress system. The number of exits required is determined by the occupant load and common path of egress travel distance. Generally, small mezzanines serving fewer than 49 occupants require only 1 exit stairway, while larger mezzanines require 2 or more.

Mezzanine code requirements for ships ladders and alternating tread stairs

What about non-standard, steep stairs like ships ladders, alternating tread stairs, and spiral stairs? Alternating tread stairs and spiral stairs are allowed to be used as a means of egress for mezzanines or equipment platforms under certain circumstances. Alternating tread stairs can be used according to IBC as a means of egress to mezzanines smaller than 250 sq ft that serve no more than 5 occupants. Alternating tread stairs can also be used as a secondary means of egress to larger mezzanine structures for areas with space restrictions. Ships ladders are not allowed to be used as a means of egress for any mezzanines. For an equipment platform, OSHA 1910.25(b)(8) states that spiral, ship, or alternating tread-type stairs are used only when the employer can demonstrate that it is not feasible to provide standard stairs. Having a space limitation is an allowable demonstration of feasibility for these devices. Alternating tread stairs have been shown to be the safest type of stair for space-restricted applications for mezzanine egress. Alternating tread stairs provide users with adequate tread depth to improve stability and ensure a safe descent down the stairs. This video below demonstrates walking down the alternating tread stair vs a steep stair.  

Mezzanine access stairs allowed by building code

IBC allows use of alternating tread stairs and spiral stairs for certain types of mezzanines. The below table outlines the allowable use of each device for accessing mezzanines.

Stair  / Ladder Type	IBC Allowable Use as Means of Egress to Mezzanine Structures
Alternating Tread Stairs	Section 1011.14 Alternating tread devices are limited to an element of a means of egress in buildings of Groups F, H, and S from a mezzanine not more than 250 square feet in area and that serves not more than five occupants.
Ships Ladders	Not allowed under IBC as a means of egress to mezzanines.
Spiral Stairways	Section 1011.10 Spiral stairways are permitted to be used as a component in the means of egress only within dwelling units or from a space not more than 250 square feet in area and serving not more than five occupants, or from technical production areas in accordance with Section 410.6
Permanent Ladders	Section 1011.16 Permanent ladders shall not serve as a part of the means of egress from occupied spaces within a building. Permanent ladders are permitted to provide access to specific work areas only.

Conclusion With more than 40 years in the metal stair business, the Lapeyre Stair team can help you design and manufacture industrial stairs for mezzanine and equipment platform access to meet either IBC or OSHA standards. We look forward to helping!