Design & Construction

Ladders are manufactured with specifications to meet an intended purpose, and they must never be used for any other purposes. The following general design requirements apply to ladders:

Loads - portable ladders must be able to support at least four times the maximum intended load. This includes the weight of the climber and any tools, equipment, and materials the climber intends to carry. An extra heavy duty ladder must be able to maintain 3.3 times the maximum intended load.

Angle - non-self-supporting ladders must be positioned at an angle where the horizontal distance from the top support to the foot of the ladder is one-quarter the working length of the ladder. Job-made wooden ladders should have an angle that equals 1/8 the working length. This is because job-made ladders may not be as strong as commercially manufactured ladders, and this angle minimizes the strain on the ladder joints.

Rungs - ladder rungs, cleats, or steps must be parallel, level, and uniformly spaced when the ladder is in use. Rungs must be spaced between 10 inches and 14 inches apart, and the rungs must be skid-resistant and shaped to prevent a climber's foot from sliding off.

To learn more about Ladder & Stairway Safety visit our Ladder & Stairway Safety Online Training web page.