What is the support ratio for extension ladders when in use?

The support ratio for extension ladders refers to the safe angle at which a ladder should be positioned against a support structure to ensure stability while in use. A 4:1 ratio signifies that for every four units of height the ladder reaches, the base of the ladder should be placed one unit away from the wall or support structure. This ratio provides optimal balance and helps prevent the ladder from tipping over, ensuring safety for the user.

This standard is crucial in ladder safety guidelines established by OSHA and other safety organizations because it promotes proper placement, reducing the risk of accidents related to ladder misuse. Adhering to the 4:1 ratio helps ensure that the ladder remains stable during use, allowing workers to focus on their tasks without undue concern for falling or other safety hazards associated with improper ladder use.