Design requirements

• OSHA sets standards for mobile ladder stands and platforms that include the proper depth and rise of steps and when handrails, midrails, guardrails and toeboards are required.

The Occupational Safety and Health Administration (OSHA) believes that employers have control over design requirements, whether constructing their own equipment or making purchasing decisions to ensure the equipment meets the requirements. Design requirements for both mobile ladder stands and platforms include:

• Steps uniformly spaced,
• Riser height no more than 10 inches (25 cm),
• Step depth no less than 7 inches (18 cm),
• Step stringers are not more than 60 degrees measured from the horizontal.

If an employer can demonstrate that meeting these requirements is not feasible, the employer can have steeper slopes or use vertical rung ladders, provided the units are stabilized to prevent tip overs. For example, there may be a workspace where the employer needs to use a mobile ladder stand platform, but the unit does not fit. In that situation, OSHA believes it would be appropriate to use an alternative unit with a steeper stringer slope or a vertical rung ladder that takes up less space.

Mobile ladder stands and platforms must have handrails on both sides if the top step or platform height is 4 feet or more above the lower level. The handrail height must be a minimum of 29.5 inches to a maximum of 37 inches. The distance must be measured from the front edge of a step.

In some applications, OSHA allows removable gates or non-rigid members (e.g., chains) instead of handrails. For example, if an employee is required to place or remove boxes from a shelf, a permanent handrail or guardrail system may create a fall risk or interfere with placing or removing the box, so using a removable gate or chain may be safer. If an employer uses a removable gate or chain, the stand or platform must be placed so there is no gap between the unit and shelf that could result in a worker falling. After the task is complete, the gate or chain must be replaced.

Mobile ladder stands with a top step above 10 feet must have:

• Protection on three sides by handrails, midrails, and toeboard,
• Handrails at least 36 inches in height,
• A top step depth of at least 20 inches from front to back, and
• A standing area within the base frame.

Mobile ladder platforms with platform heights at least 4 feet and up to 10 feet must have handrails at least 36 inches high, and midrails.

Mobile ladder platforms above 10 feet must have guardrails that comply with 1910.29(b). They must also have toeboards that comply with 1910.29(k)(1) as follows:

• A height of 3.5 inches,
• A clearance above the platform not more than 0.25- inches,
• Solid or have no gap that exceeds 1 -inch, and
• Capable of withstanding a force of at least 50 pounds, applied downward and outward.