With OSHA’s new Walking-Working Surfaces and Personal Protective Equipment (Fall Protection Systems) standard comes some clarification as to when “stairs” must be provided vs. using a ladder. In the new standard, paragraphs (b)(7) through (9) specify when and where employers MUST provide standard stairs, and under what conditions employers may use spiral, ship, or alternating tread-type stairs. OSHA has simplified and reorganized the existing rule (§ 1910.24(b)) to make the requirements clearer and easier to understand. The old standard, 1910.24(b), was pretty clear, yet often over looked; this new standard states:
In paragraph (b)(7), like existing § 1910.24(b), employers are REQUIRED to provide “standard stairs” (i.e. stairways that are fixed or permanently installed) to allow workers to travel from one walking-working surface to another. The existing and final rules BOTH recognize that “standard stairs” are the principal means of providing safe access in workplaces and employers MUST provide them when operations necessitate “regular and routine travel between levels,” INCLUDING accessing operating platforms to use or operate equipment. The final provision is consistent with A1264.1-2007 (Section 6.1).
For purposes of the final rule, OSHA describes “regular and routine travel” in much the same way as the existing rule in § 1910.24(b). The term includes, but is not limited to, access to different levels of the workplace daily or during each shift so workers can conduct regular work operations, as well as operations “for such purposes as gauging, inspection, regular maintenance, etc.” (existing § 1910.24(b)). “Regular and routine” also includes access necessary to perform routine activities or tasks performed on a scheduled or periodic, albeit not daily, basis, particularly if the tasks may expose employees to acids, caustics, gases, or other harmful substances, or requires workers to manually carry heavy or bulky materials, tools, or equipment (existing § 1910.24(b)).
Alternating Tread-Type Stairs
FIRST, know this – OSHA does not consider alternating tread-type stairs to be “standard stairs” as defined in final § 1910.21(b).
The final rule defines this alternating tread-type stairs as
a type of stairway that consists of a series of treads usually attached to a center support in an alternating manner, such that a worker typically does not have both feet on the same level while using the stairway. The limited width of the treads makes it difficult or impossible for workers to place both feet on a single tread
Final paragraph (b)(8) allows employers to use spiral stairs, ship stairs, and alternating tread-type stairs (collectively referred to as “non-standard stairs”), BUT ONLY when employers can demonstrate that it is NOT feasible to provide standard stairs.
The existing rule (existing § 1910.24(b)), which OSHA adopted in 1972 from ANSI A64.1-1968, allows employers to use spiral stairs for “special limited usage” or as a secondary means of access but only where it is “not practical” for employers to provide standard stairs. The existing rule, however does not address either ship or alternating tread-type stairs.
OSHA issued Instruction STD 01-01-011 (April 26, 1982) allowing the use of and establishing guidelines for “a newly developed alternating tread-type stair” (See also, Letter to Mr. Dale Ordoyne, December 2, 1981 [26] ). To ensure worker safety, the instruction stated that alternating tread-type stairs MUST be designed, installed, used, and maintained in accordance with manufacturer’s recommendations. In addition, OSHA said alternating tread-type stairs MUST meet the following requirements:
- The stairs are installed at a 70 degree angle or less;
- The stairs are capable of withstanding a minimum uniform load of 100 pounds per square foot with a design factor of 1.7 and the treads are capable of carrying a minimum concentrated load of 300 pounds at the center of any treadspan or exterior arc with a design factor of 1.7. If the alternating tread-type stairs are intended for greater loading, the employer must ensure the stairs are constructed to allow for additional loading; and
- The stairs are equipped with a handrail on each side to assist employees climbing or descending the stairs.
OSHA announced in both STD 01-01-011 and the 1982 letter of interpretation that it would include provisions on ship stairs and alternating tread-type stairs in the subpart D rulemaking. The 1990 proposal included provisions allowing employers to use spiral, ship, and alternating tread-type stairs and establishing design specifications for each type of stair (55 FR 13360, 13400 (4/10/1990)). No final rule came from that proposal either.
Final paragraph (b)(9), which is a new provision, requires employers to ensure that non-standard stairs are installed, used, and maintained in accordance with manufacturer’s instructions. Since 1982, OSHA Instruction STD 01-01-011 has applied this requirement to alternating tread-type stairs. Although final § 1910.22(d) already requires that employers inspect and maintain walking-working surfaces in a safe condition, OSHA believes that specifically requiring that non-standard stairs comply with the instructions or provisions the manufacturer has issued for the installation, use, and maintenance is critical to ensure that unique aspects of these stairs are identified and addressed. OSHA also believes this requirement is necessary to minimize potential risks inherent in spiral, ship, and alternating tread-type stairs (e.g., reduced tread depth, increased stair angle, improper climbing techniques) and to ensure those stairs are safe for workers to use. OSHA notes that final paragraph (b)(9), like final § 1910.22(d), applies to existing spiral, ship, and alternating tread-type stairs as well as non-standard stairs installed after the final rule is effective.
Standard Stairs
Something we do not see often from OSHA… OSHA grandfathers in the riser heights and tread depths of existing stairs even if they are less than 9.5 inches.
Final paragraph (c)(1) and existing § 1910.24(e), requires employers to install standard stairs at angles between 30 and 50 degrees from the horizontal. The final rule is consistent with A1264.1-2007, which permits employers to install standard stairways at angles between 30 and 70 degrees from the horizontal, depending on the type of stairs. The final standard includes a diagram explaining that the slope for standard stairs is 30 to 50 degrees.
Final paragraphs (c)(2) and (3), require that employers ensure standard stairs have a maximum riser height and minimum tread depth of 9.5 inches. The final rule also includes an exception (final paragraph (c)(5)) on riser heights and tread depths for standard stairs installed prior to the effective date of the final rule, which is January 17, 2017. The exception specifies that employers will be in compliance with the riser height/tread depth requirements if they meet the dimensions specified in the note to final § 1910.25(c)(2) and (3), or if they use a combination that achieves the required angle range of 30 to 50 degrees.
The existing rule (§ 1910.24(e)) does not specify a maximum riser height or minimum tread depth for fixed stairs. Instead, it requires that fixed stairs be installed at an angle of 30 to 50 degrees from horizontal and allows employers to use any combination of uniform riser and tread dimensions that achieves a stairway angle within the required range. To assist employers, the existing rule (§ 1910.24(e), Table D-1) provides examples of riser height and tread depth combinations that will achieve the required angle range. The existing rule also specifies that employers may use riser and tread combinations other than those listed in Table D-1, provided they achieve a stairway angle that is within the required slope of 30 to 50 degrees.
The 9.5-inch minimum tread requirement in the final and A1264.1-2007 standards provides stepping space that is adequate to protect workers from falling. Although A1264.1-2007 (Section 6.5) requires a 9.5 maximum riser height and minimum tread depth, an explanatory note also suggests that employers consider the riser and tread requirements in IBC codes. OSHA notes that employers who have or install standard stairs with an 11-inch tread depth, which IBC-2009 requires, are in compliance with the final rule. Moreover, as mentioned above, OSHA grandfathers in the riser heights and tread depths of existing stairs even if they are less than 9.5 inches.