The History of Maximum Arresting Force

The earliest recorded fall protection tests occurred in Sweden and the United Kingdom around the time of WWII (mid to late 1940s). These tests were performed for aviation purposes in order to determine the different ways that the human body was affected by negative acceleration (or deceleration) forces. Scientists wanted to identify the level of damage the human body would experience during the deceleration forces exerted by ejection seating from airplanes. During their tests, they would use human spines from cadavers to test the different effects of deceleration forces. European studies revealed that 3,600 lbs of pressure would typically result in either serious injury or death. 

By 1979, OSHA had decided that 1,800 lbs for maximum arresting force on fall protection devices was an acceptable limit. They determined this number by dividing the damaging force established in the European studies in half. Although full body harnesses were available for use with fall protection systems, body belts were still the most commonly used harnesses. As a result of the limited use of a full body harness in industrial and construction settings, OSHA ultimately decided to reduce the allowable maximum arresting force of a fall arrest device to 900 lbs maximum arresting force. 

In 1991, the 900 lb maximum arresting force became an industry standard. OSHA decided to change this standard because of the potentially lighter weight people who may be using a fall arrest device. As we explained in last week’s blog, a person who is has less body mass will experience a higher gravitational force when their fall is arrested. And if a deceleration device has a higher maximum arresting force, in turn, it will exert more force on the body it is arresting. So, putting a lighter weight person on a deceleration device with a higher maximum arresting force will dramatically increase the amount of gravitational force exerted on their body. 

Under those particular circumstances, the amount of gravitational force administered could potentially cause serious injury or death for the person using the system. As a result of that higher potential for severe injury, OSHA decided to reduce the limit on maximum arresting forces to better ensure the well-being of lighter weight persons who were using a fall arrest deceleration device. Although OSHA still allows body belts to be used for fall protection, body belts are now only allowed to be used in very specific fall protection applications. As of 1994, OSHA only allows a deceleration device to be used in conjunction with a full body harness for fall arrest.  

Thanks for reading! Stay safe up there!