What is the difference between a Class 1 and a Class 2 SRL?

Short answer: Under ANSI/ASSP Z359.14-2021 — effective August 1, 2023 — a Class 1 self-retracting device must be anchored at or above the user's dorsal D-ring, while a Class 2 device is additionally tested for anchorage up to 5 feet below the D-ring and for leading-edge use, and must ship with a fall-clearance chart on the product and in the manual. The class describes where you may anchor and whether the lifeline may bear on a sharp edge, not how fast the device stops you. It replaced the older Class A / Class B system, which described maximum arrest distance instead — which is why a Class A device does not simply become a Class 1 device.

SRL Class 1 vs Class 2: the ANSI Z359.14-2021 classes explained (2026)

If you bought a self-retracting lifeline before 2023 and a new one after, the labels no longer match. The old device says Class A or Class B; the new one says Class 1 or Class 2. Most buyers assume the letters were simply renumbered. They were not — the 2021 edition of ANSI/ASSP Z359.14 changed what the class measures, from stopping distance to anchorage position. This reference is for the safety manager, foreman, or buyer who has to mix old and new SRLs in one program and needs to know which device may be anchored at foot level, what the class does not tell you, and how to read a device already hanging in the gang box.

Why this matters.
Anchoring a device below the dorsal D-ring when it was not tested for it adds free fall the device never accounted for. OSHA caps free fall in a personal fall arrest system at 6 feet under 29 CFR 1926.502(d)(16)(iii), and a foot-level anchor on a 6-foot device can reach that ceiling before the brake has done anything. The class on the label is the fastest way to know whether the device in your hand was built for that.

The two classes at a glance

Read the table the right way round: the performance limits are the same for both classes. The class is not a quality tier and Class 2 is not "stronger." The only thing it changes is where the anchorage is permitted to sit relative to your back.

What changed in 2021, and what Class A and Class B actually meant

The 2014 edition classified devices by how far you travelled before the device stopped you. The 2021 edition, effective August 1, 2023, reclassified them by anchorage position and unified the stopping distance. Side by side:

The test-weight increase from 282 to 310 pounds is the change with the widest practical reach, because it reflects a fully kitted worker — tools, boots and everything carried — rather than body weight alone.

Why "Class A becomes Class 1" is the wrong way to think about it

This is the single most confused point in the transition, and published sources genuinely disagree. Some manufacturer bulletins present a two-column table that lines Class A up against Class 1 and Class B against Class 2, which reads as a conversion. Others state explicitly that the designations do not transfer and must be treated as separate systems.

The specifications settle it. Class A required a maximum arrest distance of 24 inches; Class 1 permits 42 inches. Those are different requirements, so the two labels cannot describe the same test. More fundamentally, the letters classified stopping distance and the numbers classify anchorage position — they measure different properties, so there is no arithmetic that turns one into the other. A device carries a 2021-edition class only because the manufacturer certified it to the 2021 edition; it is not a relabelling exercise a distributor or an employer can perform on paper.

The practical rule: do not infer a device's anchorage class from its old letter. If the label says Class A or Class B, the device was certified to the 2014 edition, and the question "may I anchor this at foot level?" has to be answered from the manufacturer's instructions for that specific device, not from the class.

Choosing between Class 1 and Class 2

Work from the anchor you actually have, not the device you already own.

• Overhead anchor available, worker below it — a Class 1 device is the correct and usually lighter, cheaper choice. Keeping the anchor overhead is also what keeps free fall short and swing fall small.
• Anchor at foot level, or at the walking surface — you need a Class 2 device. This is common on steel, on flat roofs anchored to the deck, and anywhere the only structure is underfoot. Because the class is edge-rated, a Class 2 device also covers the case where the lifeline can bear on the edge you are working next to.
• Anchor below the D-ring by more than 5 feet — outside the Class 2 envelope. Re-rig the anchor or change the system; no SRL class covers it.
• Mixed fleet — the safest program rule is to treat every device as Class 1 unless its own label and manual say otherwise, because that is the restrictive case. Note the converse too: a Class 1 label does not by itself forbid every below-D-ring use — some manufacturers permit a stated amount of below-D-ring anchorage on specific Class 1 models where there is no edge hazard, and that permission comes from the manual, not from the class.

What the class does not tell you

One rating is built into the class and two travel separately from it. Getting that backwards is where real incidents come from.

• Edge capability is built into Class 2, not bolted onto it. The 2021 revision retired the separate SRL-LE type and folded leading-edge performance into the class structure: a Class 2 device is drop-tested with the lifeline loaded over a thin steel edge (0.005 in / 0.13 mm) as part of qualifying for the class. So Class 2 answers the anchor-height question and the sharp-edge question together. If you are still reading an SRL-LE marking, you are holding a device certified to an older edition.
• Device type is separate. Z359.14-2021 designates three types: a plain SRL, an SRL-R with integral retrieval capability for confined-space and rescue use, and an SRL-P personal unit worn on the harness. SRL-LE is no longer among them. A device carries one type and one class — an SRL-P that is also Class 1, for example.
• Clearance is still yours to check. The class narrows the anchorage question; it does not produce a clearance number. For a Class 2 device, use the chart the standard requires the manufacturer to print. For everything else, run the calculation.

Reading the label on a device you already own

1. Find the standard and edition — you are looking for "ANSI/ASSP Z359.14" followed by 2014 or 2021.
2. If it reads 2021, read the class as 1 or 2; that answers the anchorage question directly.
3. If it reads 2014 (or 2012), the class will be a letter. Ignore the letter for anchorage purposes and open the manual to find the permitted anchorage position.
4. Check the type (SRL, SRL-P, SRL-R). On a 2021-edition device you will not find a separate SRL-LE marking — Class 2 is the edge-rated class.
5. If the device is Class 1 but you need to anchor below the D-ring, the only thing that can authorise it is the manufacturer's instruction manual for that model, and only where there is no edge hazard.
6. On a Class 2 device, confirm the fall-clearance chart is present and legible — the standard requires it on the product, and an unreadable label is a retirement trigger in its own right.

A device certified to the 2014 edition is not automatically non-compliant. Manufacturers had to certify newly manufactured devices to the 2021 edition from August 1, 2023; devices already in service continue to be governed by their own manual and by the inspection regime that applies to them.

Worked example: two anchors on the same roof

A two-person crew is replacing rooftop HVAC curbs on a low-slope commercial roof. One worker will operate under a permanent overhead davit near the penthouse; the second will work 40 feet away where the only structure is a certified deck anchor at the walking surface.

Worker one is anchored above the D-ring, so a Class 1 device is correct — for example a compact unit from the self-retracting lifelines we cover. Worker two is anchored at foot level and the lifeline can bear on the curb edge, so that position calls for a Class 2 device — one rating covers both conditions, because leading-edge performance is part of what qualifies a device as Class 2. A Class 1 device is not the class for this work unless its own manual specifically permits the anchorage position, and no Class 1 manual will permit the edge exposure.

Both workers wear a compliant full-body harness, and the deck anchor must hold 5,000 lb for the one worker attached to it under 29 CFR 1926.502(d)(15) — if the second worker later clips to the same point, that anchor now needs 10,000 lb, because the requirement is per employee attached. Before either ties off, the crew confirms clearance: worker one from the standard calculation, worker two from the Class 2 device's printed chart.

Frequently asked questions

Further reading on this site

• Fall restraint vs fall arrest — the system-level choice before the connector class question.
• Shock-absorbing lanyard vs SRL — the connector choice one level up from the class question.
• How to calculate fall clearance — the calculation to run whenever there is no printed chart.
• Fall protection anchor requirements — the 5,000 lb per-employee rule and the qualified-person alternative.
• Best self-retracting lifelines — the devices we cover, compared by application.
• Cable vs web SRL — lifeline material, a separate axis from class.
• Aerial lift fall protection requirements — where anchorage position is dictated by the machine.
• Self-retracting lifelines — the SRL category on this site.