Self-Retracting Lifelines – Class A or Class B?

When you or your workers are up in the air working at a height, it is imperative to ensure not only that you use fall protection equipment, but that you use the right fall protection equipment. A fall prevention system is composed of an Anchor, a Body harness, and a Connector, often being a lanyard with a deceleration or energy absorbing mechanism. In this article we will discuss some of the differences among SRLs (self-retracting lifelines), how to go about choosing the proper one for the job and the differences between Class A & Class B in SRLs.

It’s been several years now since the introduction of ANSI standard Z359.14-2012 that classified two types of SRLs according to dynamic performance testing and detailed the differences and capabilities of the two. Basically the two types are distinguished by their allowable arrest distance, but there is more to know than just that.

To start, Class A devices allow for a maximum of 24” arrest distance while Class B devices have a maximum of 54” arrest distance. The arrest distance is the distance from when the device begins decelerating the fall and when the fall comes to a complete stop. Both Class A and B SRLs have a max peak arresting force of 1800 Lbs. What differs between the two is the average arresting force. This difference arises because of the shorter arrest distance between the two. Stopping a falling object in 2 feet is going to inflict much more stopping force on the object than stopping in just over 4 feet. Class A devices (24”) allow for an average arresting force of 1350 lbs. while Class B devices (54″) allow for an average arresting force of 900 lbs. But again both classes of SRLs have a max peak arresting force of 1800 lbs.

A special device with leading edge or sharp edge capabilities is to be used in situations that require it. Standard SRLs are not designed for use in these circumstances and may become damaged and break. Leading edge devices are approved for overhead as well as foot level tie offs.

An extra two feet of fall distance can be the difference between a hitting the ground or other objects. When calculating the amount of fall distance needed, there are several factors to take into consideration. A 3’ safety factor is required, and 1’ to 1.5’ must also be added to account for lanyard stretch. It is also important to use the D ring on the worker as your point of reference for measurement. This is measured from the D ring to the sole of the workers shoe.  Our friends at FallTech have a pretty good diagram that may be helpful in determining your required fall clearance.

The best way to be assured that you are using the right equipment is to read the markings and limits on the fall arrest systems you are using and read the manual. Also be sure to inspect your equipment regularly. ANSI details guidelines for PFAS inspection depending on the frequency of your usage.

Be sure to keep up with ANSI and OSHA regulations to stay up to date on your safety practices and ensure you have a trained competent person on the jobsite. If you have product specific questions feel free to give the pros at Ohio Power Tool a call at 800-242-4424 for all your fall protection questions!

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