On most construction and industrial worksites, there’s one of two ways for workers to ascend to heights: Ladders or stairs. Both generally accomplish the same goal — getting up and down — but in some cases, one is better suited than the other. Especially with recent updates to OSHA’s fixed ladder requirements, switching to stairs might be the best option for your worksite. Consider these benefits:
- Better safety and stability for workers
- Higher load-carrying capabilities
- Less necessary training
- Improved accessibility
Not every worksite has the floor space or clearance for an OSHA-compliant stair system. This blog digs into OSHA 1910.25 to help you evaluate if switching from ladders to stairs is the right call for your business.
1. Guardrails — 1910.25(b)(1)
Stair systems are subject to the same fall protection guidelines as any other walking-working surface, as outlined by OSHA. This means that employers must provide handrails, stair rail systems, or guardrails on unprotected edges at elevations of 4 feet or more. If the stairway has more than four risers, handrails are necessary even if both sides of the stairs are enclosed by walls.
2. Vertical Clearance — 1910.25(b)(2)
The vertical clearance above any level on the stairs, including the top platform, must be at least 6 feet 8 inches measured from the leading edge. Hopefully, this will protect even your tallest worker from hitting their head and provide ample room for transporting equipment. Spiral staircases require 6 feet 6 inches of headroom from the leading edge of the tread to the underside of the next level of stairs.
3. Tread Width
Standard stairs are required to have a minimum tread width of 22 inches between vertical barriers according to OSHA 1910.25(c)(4). These could be walls or guardrails on the sides of stairs. Additionally, any platforms must be at least the width of the stairs leading up to them.
Other types of stairs have different width requirements. OSHA 1910.25(d)(1) says that spiral stairs must have at least a 26-inch tread width. This is due to the tapered shape of the tread creating less walking surface for workers. OSHA 1910.25(e)(4) specifies that ship stairs only require an 18-inch tread width since they are generally located in much tighter quarters.
4. Load — 1910.25(b)(6)
Each stair is required to support at least five times the anticipated live load for the system. For example, if you plan to have two workers transport a refrigerator up the stairs, every point on the staircase must be able to support the weight of both workers plus the fridge five times. That’s 10 workers and five refrigerators if you’re counting.
The caveat is that even if the anticipated live load is less than 200 pounds, the stairs must support no less than a 1,000-pound concentrated load at any point.
5. Angle — 1910.25(c)(1)
Standard stairs must be installed at an angle between 30 and 50 degrees from the horizontal, that is, the ground or any level walking surface. Ship stairs are installed between 50 and 70 degrees from the horizontal, resulting in a much steeper, ladder-like climb.
6. Riser Height
There are two considerations when it comes to the riser height of stairs: Uniformity and measurement. According to OSHA 1910.25(b)(3), every type of stair system is required to have a uniform riser height. This makes it easier and safer for workers to ascend and descend even if they can’t see their feet.
Standard and spiral stairs both must adhere to a maximum riser height of 9.5 inches per OSHA 1910.25(c)(2) and 1910.25(d)(2).
Ship stairs have open risers (like ladders) with a vertical rise in between treads of 6.5 to 12 inches per OSHA 1910.25(e)(2).
7. Tread Depth
Like riser heights, tread depth must be uniform for an entire set of stairs. For standard stairs, the minimum acceptable tread depth is 9.5 inches per OSHA 1910.25(c)(3). Spiral stairs are a little trickier due to the tapered shape of the tread necessary for the circular ascent. In 1910.25(d)(4) spiral stairs must have a minimum tread depth of 7.5 inches measured from a point 12 inches from the narrower edge of the tread.
Ship stairs have a minimum tread depth of just 4 inches specified by 1910.25(e)(3).
8. Swinging Doors — 1910.25(b)(5)
When a door or swinging gate opens directly onto a staircase, a platform must be provided to avoid knocking workers back down the stairs. This platform must be usable at all times, even when the door is in motion. This means that the swing of the door cannot reduce the usable walking-working surface of the platform to less than 22 inches.
If this guide is helpful to you, check out the downloadable version on our resource page for quick reference whenever you need it.
Switching from ladders to stairs is a great way to upgrade your worksite, but it’s not a solution you can jump right into. There are a lot of financial and regulatory considerations to make first. Hopefully, this guide gave you a good idea of whether switching to stairs is in the picture for your worksite. But keep in mind that it’s an overview. If you’re serious about making the switch, your next step is to review OSHA 1910.25 in detail and get in touch with a fall protection expert like EDGE to assess your worksite and what options might be best for you.
