OSHA safety regulations, contractor safety programs, and ladder manufacturers alike do not require fall protection systems for portable ladders. This is primarily due to the fact that while ladder use is certainly involved in many accidents, it’s simply proper usage of the ladders that will provide a safe working environment. For instance, the angle that a straight or extension ladder is placed against a wall or structure is critical to ladder safety. If the base of the ladder is placed too far away from the wall (see figure 1), there is more outward lateral pressure on the feet than the ladder was designed for. What this means to you is that the ladder is much more likely to slip out from under you than you realize. Ladder engineers design the foot dimensions and materials based on the anticipated load, but only at the correct angle – any more lateral forces on the feet is just asking for trouble.

On the other hand, placing a ladder too close to a wall or structure is just as bad. A ladder set with its base too close the wall can make climbing more difficult, and a slip of the hand disastrous. When the ladder is set correctly, there’s enough angle to allow the climber’s body to rest against the ladder rungs if desired to provide rest while climbing, or when working on the ladder, enough lateral pressure against the ladder rungs for the body to hold itself against the ladder. Also, in some cases, the worker could fall backwards from the ladder, or the ladder could tip backwards. Also, with the base too close to the structure, there’s insufficient lateral pressure of the siderails against the wall or structure which could lead to the ladder sliding or falling sideways.

So, what is the correct angle to set a straight or extension ladder? Well, the actual figure in the OSHA regulations (and for that matter, ladder manufacturers) is approximately 75½ degrees. So when the approximate angle is within half a degree, there’s not a lot of room for error! To get the correct angle, there is a simple formula. Take the height where the ladder touches the wall or structure, and set the base of the ladder one-fourth of the height measurement from the base of the wall. This works out to the 75½ degrees.

Remember, setting the straight or extension ladder at the exact, correct angle allows for the maximum designed traction of the feet, the correct lateral pressure against the wall, and the safest, most comfortable angle for climbing and working off the ladder.

This entry was posted on Monday, August 24th, 2009 at 11:34 am and is filed under OSHA, safety, safety tips. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.