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The Guardian Fall Team Blog

Over the course of the last forty years, the amount of Americans killed in automobile accidents has been nearly cut in half from a peak of over 54,000 in 1972 to less than 33,000 in 2012. [1] This decrease is much accredited to manufacturer and state laws focusing on airbags, seatbelts, and speed limits. Additionally, vehicles of the 1970’s were heavy and rigid making them more accident prone; whereas, vehicles that are made today are designed to crumple and absorb forces.

In a similar fashion to vehicular design, innovation in the realm of fall protection has evolved. Originally, fall protection systems were designed to be heavy and rigid in hopes of impeding the occurrence of any falls. These systems have since been redesigned to instead account for and absorb the force of any fall event.

The initial approach to fall protection design, akin to vehicular design, was to make a rigid system that was ‘overly-designed’. For example, when we consider a horizontal lifeline system, OSHA requires a 2:1 safety factor. If an end anchor is designed for an ultimate load of 5,000 pounds than there isn’t a reason for other components to be much stronger. This means that if a half-inch diameter cable is used (breaking strength of approximately 20,000 pounds), than a system component is ‘overly-designed’ by 4:1. A common feature of ‘overly-designed’ horizontal lifelines is the lack of energy absorbers. Without energy absorbers, end anchor loads on horizontal lifelines can easily exceed 5,000 pounds which creates the challenge of designing structures for a load of more than 10,000 pounds.

Rather than looking at the strength of each individual component of the horizontal lifeline system, designers should look at the strength of the overall system. The system design should focus on ensuring that high loads are reduced rather than allowing extreme loads to be placed on the anchor to roof structure connection. Examining the strength of the overall system means that the input and output design loads should first be considered before selecting components. Once these loads are determined, each component of the system should be analyzed. In addition to the engineering analysis, testing of the entire system should be performed to ensure that overall safety factors are maintained.

When ESG designs horizontal lifelines, we focus on making systems that absorb forces as best they can without creating unsafe fall clearances. We believe that this approach to design is a key step to reducing accidents in the fall protection industry. If you have further questions on the topic of shock absorbing fall protection design or horizontal lifelines, feel free to contact me at 1.800.466.6385 or via email at This email address is being protected from spambots. You need JavaScript enabled to view it.

[1] http://en.wikipedia.org/wiki/List_of_motor_vehicle_deaths_in_U.S._by_year