In addition to a wide range of shapes and sizes, ladders come in many different material types. The most common are wood, metal (iron or aluminium) and fiberglass. In its regulation, OSHA makes a main distinction between metal and wooden ladders, and thus publishes separate regulations. In this article we detail the safety requirements for portable wooden ladders.
The 29 CFR 1910.25 OSHA standard addresses wooden ladders, and is divided into sections that specify their applications, the characteristics of the materials, the construction requirements, and their care and usage by the user. It should be noted that this standard applies to wooden ladders of common use, and not to specialty tools such as library, attic, extension, tripod ladders, or other tools that may have specific operative and construction characteristics. The construction wood that is used must be high-density, and provide a surface free of splinters and sharp edges.
A table published in the standard defines the maximum admitted length for each typology of wood ladder. Type 1 Industrial Step-ladders must have a maximum length of 20′; for Type 2 Commercial Step-ladders the limit is 12′; Type 3 Household Step-ladders can’t exceed 6′. For these three types, there are additional requirements: the minimum width between side rails at the top, inside to inside, shall be not less than 11 1/2 inches; from top to bottom, the side rails shall spread at least 1 inch for each foot of length; a metal spreader or locking device of sufficient size and strength to securely hold the front and back sections in open positions shall be a component of each tool. The other types listed in the length limit table are: Rung (30′), Two-Section Rung (60′), Trestle (20′), Painter’s (12′), Mason’s (40′) and Side-Rolling (20′) Ladders. For Two-Section Rung Ladders there’s the additional special requirement that their rails must fit into each other and that the upper section can be raised/lowered.
Wood is a perishable material, so special care must be assured to ensure the serviceability and safety of portable wooden ladders. All joints must be kept tight; wheels, locks and pulleys need proper lubrication; ropes must be checked and replaced if needed; a periodical cleaning of the wood surface must be done. Also the place where wood ladders are kept when not in use is important, because if they are stored on the outside, rain and other atmospheric agent may damage its parts and structure.
The OSHA standard also specifies how these tools have to be used to ensure the climber’s safety in all operative conditions. The distance from the foot to the top support (where it touches the opposite wall or leans against a roof) must be about four times bigger than the distance from the foot to the opposite wall; this ensures that the tools is placed at a safe angle. No more than one person at a time should climb a wooden ladder. The foot of the ladder must be placed on the ground, and no object should be used to increase its height.
Following these prescriptions is mandatory for wood ladders manufacturers; moreover, users should be aware of these indications as well, in order to ensure that they always work safely and keep their tools in proper conditions.