What is the recommended minimum height for an extension ladder to safely lean against a structure?

The recommended minimum height for an extension ladder to safely lean against a structure is typically around 16 feet. This height ensures that the ladder extends at least three feet above the point of support to provide a secure handhold when entering or exiting at the top. This guideline is crucial for enhancing safety and stability, as it helps to prevent the user from overreaching or losing balance while working on the ladder.

In practice, the ladder should also be set at a proper angle, which is generally recommended to be about 75 degrees to the ground. This angle, combined with the proper extension height, allows the ladder to maintain its stability and reduces the risk of tipping over. Thus, ensuring that the ladder is sufficiently tall not only facilitates safer access but also contributes to overall working safety protocols when undertaking work at height.