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ANSI Class 2 SRLs: An Essential Guide

ANSI updated its Z359 standard with new classifications and safety testing for self-retracting lifelines (SRLs). The new Class 2 SRL received special focus in the new standard. Discover why.

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One thousand.  

That’s the estimated number of the US construction industry’s work-related deaths per year. Almost 400 of these workers died from slips, trips, and falls in 2021 alone.1 That was also the same year a new ANSI standard arrived aiming to enhance worker safety and put a dent in fall-related deaths and injuries.

Leading edge photo Blog

You may have heard about these guidelines: ANSI Z359.14-2021 became effective on August 1, 2023, two years after publication. The American National Standards Institute (ANSI) and the American Society of Safety Professionals (ASSP) enacted the guidelines to simplify classifications and increase safety on Self-Retracting Lifelines (SRLs).

Of the two new classes, the Class 2 SRL has received the greater attention from regulators and users. That attention, in turn, has sparked questions like:

  • What is a Class 2 SRL?
  • What is an SRL-P?
  • Is a Class 2 SRL better than a Class 1?
  • Where do I use a Class 2 SRL?

Let’s break down the essentials you need to know about Class 2 SRLs. 

A Primer on ANSI Z359 Types and Classes

ANSI first set guidelines on fall protection equipment in 1992 with the Z359.1 Fall Protection Code. Two decades later, ANSI updated its standard with guidelines for Self-Retracting Devices (SRDs), including SRLs, with Z359.14. The 2012 guidelines divided SRDs into Class A or B based on overhead anchorage performance. A revision in 2014 defined that a steel edge sharpness in leading edge testing be 0.005 inch.

The latest standard, Z359.14-2021, classifies SRDs into three types:

  1. Self-Retracting Lifeline (SRL)
  2. Self-Retracting Lifeline – Personal (SRL-P)
  3. Self-Retracting Lifeline - Rescue (SRL-R)

ANSI defines an SRL as a “mechanical fall arrester, featuring a locking mechanism and energy management system to arrest the fall and limit the forces imparted to the user.”2 An SRL-P is meant for individual use and mounted onto a full body harness. An SRL-R is a mechanical fall arrester with the added function of rescue and retrieval post-fall arrest, by raising or lowering a fall-arrested user to safety.

  Class A Class B Class 1 & 2
Max Arrest Force 1,800 lbs. 1,800 lbs. 1,800 lbs.
Avg. Arrest Force 1,350 lbs. 900 lbs. 1,350 lbs.
Max Arrest Distance 24 in.* 54 in.* 42 in.*
*The Average Arrest Force limit increases during hot, cold, and wet conditioned tests.


The latest standard categorizes SRDs into Class 1 or 2 versus the earlier Class A and B. Above shows key performance requirements between them.

What is a Class 2 SRL?

An ANSI Class 2 SRL has two key criteria.

back_harness_vector copy

First, a Class 2 SRL anchors at, above, or up to 5 feet below a dorsal D-ring tie-off. This differs from a Class 1 SRL which anchors at or above a dorsal D-ring only.

SRL-Category-home-page copy

Second, a Class 2 SRL has a retractable lifeline tested and rated for use within leading edge environments. By contrast, a Class 1 SRL’s lifeline is not rated for such use. Why the leading-edge requirement? ANSI concluded that a user tying off below D-ring has a high likelihood of his or her potential fall seeing an edge hazard.

To address this possibility, a Class 2 SRL has its lifeline tested in drop tests along a thin steel edge 0.005 in. (0.13 mm) thick. To put that sharpness into perspective, a razor blade’s maximum thickness is 0.0105 in. (0.27 mm).3 

Is a Class 2 SRL Better Than a Class 1 SRL?

It’s best not to think of which class is better. Because it supports below-D-ring anchorage and is rated for use near leading edges, a Class 2 SRL gives users a greater range of potential use on a worksite.

When and Where to Use an ANSI Class 2 SRL 

Best practice has any worksite compliant with ANSI’s latest standard. Any ANSI Z359-compliant worksite thus requires a Class 2 SRL:

  • When a user ties below D-ring
  • Where a user is exposed to a leading edge.

In either or both circumstances, an ANSI Z359-compliant worksite demands a user have a Class 2 SRL. Outside of an ANSI Z359-compliant worksite, a user can use a Class 1 SRL to tie-off below his or her D-ring. However, a user must use a Class 2 SRL when exposed to a leading edge.

To reiterate: Best practice has any worksite compliant with ANSI’s latest standards. 

How to Identify a Class 2 SRL

The new ANSI standard requires an SRL to have two identifiers.


First, every Class 2 SRL must have a label that appears exactly as above. The label will measure 1 inch for SRLs and a ½-inch for SRL-Ps.

call out 5-1

Second, every Class 2 SRL must have a chart or diagram that shows the minimum required fall clearance. See FallTech’s version above for reference.

Can You “Grandfather” or Convert an Old SRL to Class 2?

You cannot grandfather a Class A or B SRL to a Class 1 or 2 standard. An SRL only complies with the standard on its product label. A 2014 Class B SRL-LE, for example, does not comply with ANSI's 2021 Class 2 standard. The testing criteria have changed, and safety factors have increased.

Contact your manufacturer to find out if it offers an upgrade process for your SRL like FallTech.

In summary, a Class 2 SRL:

  • Anchors at, above, or up to 5 feet below a dorsal D-ring.
  • Is rated for use in leading edge environments.
  • Must have a “Class 2” label and fall-clearance diagram.

For references, browse FallTech’s list of industry-leading Class 2 SRLs. For all things related to fall protection, always stay connected with FallTech!


  1. US Bureau of Labor Statistics
  2. American Society of Safety Professionals
  3. US International Trade Administration


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