Project Experience: Safety Harness Fails

A safety device, known as a fall limiter, is meant to reduce the stress on a person in the event of a fall. Under normal circumstances a 220 pound man falling roughly 4 to 6 feet can have forces upwards of 3000 pounds on his body when a safety line runs out of slack. A specific fall limiter submitted for analysis was designed to reduce the forces to 300 pounds. However, the device submitted was involved in an accident when the cable snapped. The question was “Did the fall limiter fail resulting in forces near 3000 pounds which is the limit for the cable”. Testing performed in the laboratory revealed that the actual fall limiter functioned properly limiting the force to 300 pounds for a 220 pound man. Since the device exhibited signs of repeated use and the cable displayed evidence of wear it is likely the accident was the result of insufficient maintenance rather that failure of the fall limiter itself.