From our friends at Guardian Fall Protection…
SRLs Have Class – Two Actually: Understanding the Difference Between Class A & Class B SRLs
In August of 2012, ANSI, in their Z359.14-2012 Safety Requirements for Self-Retracting Devices for Personal Fall Arrest and Rescue Systems (since revised to Z359.14-2014), divided SRLs into two classes. These classes are defined based on an SRL’s maximum potential arrest distance and maximum potential average arrest force. SRLs with a maximum arrest distance of 24 inches are labelled Class A, and those with a maximum arrest distance of 54 inches are labelled Class B. Average arrest forces are capped at 1,350 lbs. for Class A SRLs, and 900 lbs. for Class B SRLs, with the maximum arrest force of 1,800 lb. for both classes.
Breaking It Down.
Going only by the numbers, it seems no matter which SRL you choose you will be trading arrest force for arrest distance. On its face, that’s true. But if we take a more nuanced look into the real-world meaning of those numbers, it becomes clear that what seems like a compromise is actually a means to provide the most appropriate solution for a given fall protection scenario.
First, it’s important to understand that both classes of SRLs are OSHA 1926.500 subpart M compliant because they both, “limit [the] maximum arresting force on an employee to 1,800 pounds (8 kN) when used with a body harness.” This means that no matter what class of SRL you choose, you can rest assured of OSHA compliance. When it comes to the difference in average arresting force between the two classes (1350 lb. and 900lb., respectively) it is really just a by-product of how quickly the SRL stops a fall.
Read the rest of this post here.