The Essential Guide to Self-Retracting Lifelines

In elevated work areas with fall hazards, a Self-Retracting Lifeline (SRL) provides the secure mobility a worker needs to get the job done. This guide will explain how SRLs work, when to use them, and how to maintain them so crews stay safe and productive.

Key Takeaways  

• Understand how SRLs work and protect against falls.
• Know when to use SRLs and when to choose EALs.
• Follow clear steps to select the right SRL for your job site.
• Set up effective inspection and maintenance routines.

What is a Self-Retracting Lifeline?  

The US Occupational Safety and Health Administration (OSHA) defines an SRL as “a deceleration device containing a drum‑wound line that can be slowly extracted from, or retracted onto, the drum under slight tension during normal movement by the employee. At the onset of a fall, the device automatically locks the drum and arrests the fall.”

Similarly, the American National Standards Institute (ANSI) and American Society of Safety Professionals (ASSP) define an SRL as “a device that contains a drum wound line that automatically locks at the onset of a fall to arrest the user, but that pays out from and automatically retracts onto the drum during normal movement of the person to whom the line is attached.”

 

SRLs belong to a broader group called Self-Retracting Devices (SRDs). The simplest SRD works like a seatbelt on a reel—it lets you move freely but locks instantly if you fall.

 

Modern SRLs go further. They’re built to handle higher forces, use teeth-and-pawl braking for faster arrests, and feature energy absorbers (“shock packs”) to reduce the impact you feel during a fall.

An SRL is known by various names and nicknames, including:

• Self-Retracting Device (SRD)
• Personal Fall Limiter (PFL)
• Retractable
• “Backpack”
• “Block”
• “Yo-Yo”

An SRL includes three main parts:

1. Housing
2. Lifeline
3. Connectors

 

The housing holds the SRL’s internal parts, including the rotating drum and retraction spring.

 

An extendable and retractable lifeline—usually made of steel cable or synthetic webbing—connects to a ring on the worker’s safety harness.  

 

The connector is the component that connects the SRL to an anchor and/or a user’s safety harness. Carabiners and snap hooks are common examples of SRL connectors. 

As the worker moves, the lifeline extends and retracts smoothly. If a fall occurs, a braking mechanism locks the lifeline and limits the distance of the fall. 

When Do You Need a Self-Retracting Lifeline?

You need an SRL whenever workers operate at height but must stay mobile while remaining securely tied off.

 

OSHA requires fall protection, which can include SRLs, at the following minimum heights:

• 4 feet in general industry
• 5 feet in shipyards
• 6 feet in construction

In short, use an SRL when a worker needs fall protection at required heights, especially if he or she must move semi-freely and prevent a fall rapidly.

SRL Types by Application and Anchor Location

ANSI Z359.14-2021 groups self-retracting lifelines (SRLs) by class and type.

ANSI phased out its Class A and B in 2023. The current standard now categorizes SRLs into two classes:

• Class 1 – Tie off at or above the user’s dorsal D-ring, not for leading-edge use.
• Class 2 – Tie off at, above, or up to 5 ft below the dorsal D-ring; rated for leading-edge use.

Below are the performance requirements for the old and new classes:

ANSI SRD Classes
	Class A	Class B	Class 1 and 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.
*ANSI retired Class A and B with the new Z359.14-2021 standard. **The Average Arrest Force limit increases during hot, cold, and wet conditioned tests.

 

ANSI’s new standard introduced a new type of device, the compact SRL-P (“Self-Retracting Lifeline – Personal”), and retired another, the SRL-LE (“Self-Retracting Lifeline – Leading Edge”).

Below are the three current ANSI types:

• SRL – Standard “block” SRL anchored above, connected to the dorsal D-ring via a lifeline.
• SRL-P – “Personal” SRL that mounts directly on the harness (dorsal D-ring or tunnel).
• SRL-R – “Retrieval/Rescue” SRL, often used with tripods or davits, to raise or lower a worker to safety.

Note: Leading-edge SRLs now fall under Class 2.

Overhead SRLs

You can anchor an ANSI Class 1 or Class 2 self-retracting lifeline overhead, meaning above your dorsal D-ring. This position keeps the lifeline at the best angle to reduce fall distance and stop a fall quickly.

 

Overhead anchoring is common in jobs like drill rigs and loading stations, where workers need to move around but stay tied off. These SRLs often have extra lifeline length, giving workers more range if the line reaches their work area.

Standard Block SRLs

A “block” SRL is the classic ANSI-classified self-retracting device. The term “SRL” is often used generically for other types, which can cause confusion. In this section, “SRL” refers specifically to block SRLs for simplicity.

 

An SRL is a larger device with an anchorage connector—often a carabiner—at the top and a harness connector at the end of its lifeline. The harness connector, typically a steel snap hook or carabiner, attaches to the dorsal D-ring of the worker’s safety harness.

Early block SRLs featured heavy metal housings, but the latest designs use impact-resistant polymer bodies to reduce weight while maintaining durability. These devices can be classified as either Class 1 or Class 2, depending on their tie-off capability and leading edge rating. 

Most SRLs come with lifelines between 20- and 60-feet lengths, though there are exceptions beyond this range. The SRL’s energy absorber will be on the lifeline, right behind the harness connector.

 

The main drawback of block SRLs is weight, especially for units with longer steel cable lifelines. Fortunately, newer models, such as the FT-R have greatly reduced this issue by using lightweight materials in the housing and internal components.

SRL-Ps: Personal SRLs for Direct-to-Harness Attachment

A personal self-retracting lifeline, or SRL-P under ANSI Z359.14-2021, is a compact fall protection device that attaches directly to a worker’s safety harness. Workers connect it by the dorsal D-ring, a sleeve, or a tunnel on the harness.

 

Budget-priced Personal SRLs usually place the energy absorber on the lifeline, just behind the anchorage connector. Premium models position the absorber near the user’s dorsal D-ring. This location is ideal because it keeps the weight against the upper back, instead of swinging and pulling on the worker. Placing the energy absorber closest to the harness is always best practice.

Because it is light and easy to carry, a personal SRL works well on rooftops, in aerial lifts, and in other jobs where workers need to move freely without extra bulk. Its small size limits the lifeline to about 6 to 9 feet, but it can still meet Class 1 or Class 2 standards. All Class 2 models are also rated for leading edge use.

The FT-X is a modern SRL-P available in both classes. The FT-X Web uses Dyneema® webbing and meets Class 1 requirements. The FT-X Cable uses 3/16-inch steel cable, meets Class 2 standards, and is leading-edge-rated—making it a strong choice for tougher jobs.

Some manufacturers have created synthetic webbing that’s stronger and lighter than 3/16-inch cable. EdgeCore, for example, is a Kevlar®-reinforced material found available on the high-end SRLs.

Leading Edge SRLs

ANSI defines a leading edge as the unprotected edge of a walking-working surface. OSHA uses a similar definition, referring to it as the edge of a floor, roof, or formwork where a fall hazard exists. In plain terms, it’s the sharp or abrasive edge a worker might fall over, such as the side of a roof or a steel beam.

Under ANSI Z359.14-2021, an SRL must pass specific drop tests over a sharp edge to earn a leading-edge rating. This testing ensures the lifeline can withstand the abrasion and forces of a fall. ANSI now classifies a leading edge self-retracting lifeline under Class 2, replacing the older SRL-LE category.

 

You need a leading edge SRL when the anchor point is at foot-level or below the dorsal D-ring, and the lifeline may contact an edge during a fall. Examples include roof construction, bridge work, or steel erection. The FT-R is an ANSI Class 2 SRL rated for leading edge use, and the FT-X Cable is a compact ANSI Class 2 SRL-P that offers the same protection.

Rescue/Recovery SRLs (SRL-R)

A rescue/recovery Self-Retracting Lifeline (SRL-R) is a fall protection device that also lets you retrieve a worker after a fall. Like any SRL, it stops the fall quickly. Then it allows a rescuer to raise or lower the worker to safety.

An SRL-R works by locking the lifeline during a fall. The rescuer can switch it to retrieval mode and use a handle or crank to bring the worker up to a safe surface or lower them to the ground.

 

Workers in confined spaces, on towers, or in places where self-rescue is impossible often need an SRL-R. These devices are typically Class 1 only.

SRL-Rs usually have lifelines of 60 feet or more, giving enough reach for deep vertical rescues. Their length and retrieval feature make them essential in jobs where a fast, safe rescue can save lives.

How Do SRLs Compare to Other Fall Protection Devices?

SRLs provide more mobility and shorter fall distances than fixed lanyards, and they work automatically—unlike rope grabs that need manual adjustment. Though heavier and more expensive, SRLs combine freedom of movement with quick fall arrest, making them a top choice for many jobs.

SRL vs Lanyard: What’s the Difference?

An SRL automatically extends and retracts as you move, keeping the line taut and reducing free fall distance. It locks instantly during a fall. A lanyard is a fixed-length connector that can allow a longer fall before arrest. While lanyards are lighter and cheaper, SRLs offer greater mobility and faster fall arrest, making them safer for many applications.

SRL vs. Energy-Absorbing Lanyard: When to Choose Each

An SRL uses a retractable lifeline that stays taut as you move, reducing free fall distance and locking instantly in a fall. Many SRLs also include an energy absorber to lessen the impact. An Energy-Absorbing Lanyard (EAL) is a fixed-length connector—usually 6 feet—that relies on a built-in energy absorber to reduce the arresting force after a longer free fall.

EALs are lighter, less expensive, and have no moving parts, making them easy to inspect and maintain. However, they require a higher anchor point to meet clearance requirements and can allow a longer fall before arrest. SRLs cost more and may be heavier, but they work in more situations, including lower anchor points and leading edge applications (for Class 2 models).

Choose an EAL for straightforward jobs with overhead anchors and enough fall clearance. Choose an SRL when you need more mobility, shorter fall distances, or protection from edges and low anchor points.

How to Choose the Right Self-Retracting Lifeline

Choosing the right SRL starts with asking how and where you’ll use it. Will it be anchored overhead, at foot level, or on a leading edge? Will workers face edge exposure that requires a Class 2 SRL?

Make sure the device complies with current standards, including:

• ANSI Z359.14-2021
• OSHA 29 CFR 1910
• OSHA 29 CFR 1926
• CSA Z259.2.2 (if you work in Canada)

The right SRL should match your application, work environment, and compliance needs while providing the mobility and protection your workers require.

What to Look for in a Self-Retracting Lifeline

Finding the right SRL means following a clear, step-by-step process. Regarding SRL safety, consider your application, assess hazards, and then select the model that balances safety, mobility, and compliance. By moving through these steps in order, you ensure the SRL you choose is tailored to your exact needs.

Step 1: Determine the Application

Start by looking at how and where the SRL will be used. Will workers anchor overhead, at shoulder height, or at foot level? Is mobility across wide areas necessary, or will the work stay in a small zone?

The type of application—such as roof work, confined space entry, or warehouse tasks—guides the SRL type you need. For example, a compact SRL-P might be ideal for lifts or rooftops, while a standard block SRL may suit larger job sites where range is critical. Matching the SRL to the task ensures both freedom of movement and proper fall arrest performance.

Step 2: Identify Other Potential Hazards

Beyond basic application, consider what hazards may affect SRL performance. Will the lifeline contact a sharp or abrasive leading edge? If so, only a Class 2 SRL is appropriate.

Are there swing fall risks, confined spaces, or rescue needs? In some cases, a specialized SRL-R for retrieval may be required.

Environmental factors also matter. Exposure to heat, chemicals, moisture, or UV light can shorten the life of webbing or cable lifelines. Identifying these hazards up front helps you avoid costly mistakes and ensures the SRL provides reliable protection in real-world conditions.

Utility workers must account for the risk of arc flash hazards. The intense heat from an arc flash can quickly destroy standard fall protection materials, especially polyester webbing. Arc flash-rated SRLs use specialized materials designed to withstand these extreme conditions. For example, the FT-X EdgeCore Arc Flash features a Kevlar® lifeline and carries an ASTM F887 rating for arc flash resistance.

Step 3: Select Your Self-Retracting Lifeline

With application and hazards in mind, select the SRL that meets your requirements. Check for ANSI Z359.14-2021 compliance, confirm OSHA and CSA standards if applicable, and match the class rating to your anchor location.

Look at housing durability, lifeline material (web vs. cable), and weight. Newer models, like those using thermoplastic housings or synthetic lifelines, offer strength with reduced bulk.

Also consider inspection and maintenance ease, since an SRL must stay in service-ready condition. By weighing these factors, you’ll choose a device that delivers safety, mobility, and long-term reliability.

Browse FallTech’s Full Line of SRLs

Explore our full suite of self-retracting lifelines, including personal, overhead, leading edge, and rescue-rated models. Designed for a wide range of applications, all tested to meet ANSI and OSHA compliance.

Shop All SRLs

How to Inspect a Self-Retracting Lifeline Before Use

Always inspect an SRL before each use—never use one that fails inspection. Always refer to your SRL’s user manual for the most detailed instructions.

Start with the housing: check for cracks or missing labels, including the serial number and manufacturer information. Do not open the casing unless you are authorized to do so.

Mount the SRL before testing and always wear gloves. For cable lifelines, look for rust, cuts, fraying, bird-caging, heat damage, or crushed strands. For webbing, check both sides for tears, burns, broken fibers, or loose stitching. Any holes, major wear, or more than 10% damage means the SRL must be removed from service.

Next, inspect the connectors. Carabiners or hooks should be free of cracks, bends, or discoloration and must lock smoothly on their own.

Finally, test the lifeline: pull it out halfway and fully, checking for smooth retraction. Perform a braking test by giving sharp tugs to ensure the brake engages and holds without slipping. If any part of inspection fails, remove the SRL from service immediately.

How to Maintain Your Self-Retracting Lifeline

Proper maintenance ensures your SRL works when you need it most. Store the device according to the manufacturer’s instructions—usually in a cool, dry place away from moisture and direct sunlight.

Avoid freewheeling, which happens when you let the lifeline snap back without tension. Freewheeling can damage the spring, jam the cable, or cause the hook to slam into the housing, breaking internal parts. Always maintain light tension during retraction.

Keep in mind that SRLs are designed for fall arrest, not restraint. Never use them to keep a worker from reaching an edge. With regular inspections and careful handling, your SRL will stay reliable and ready to protect workers on the job.

What Does ANSI Z359.14 Say About SRL Safety?

ANSI Z359.14-2021 is the key safety standard for self-retracting devices, including SRLs. It sets design, performance, and testing requirements to ensure lifelines perform reliably in real-world conditions. The standard establishes two classes: Class 1 SRLs, which must be anchored at or above the dorsal D-ring, and Class 2 SRLs, which can be anchored up to five feet below and are rated for leading-edge use.

The standard also specifies testing for dynamic performance, fall arrest forces, and edge exposure. Devices must pass drop tests over sharp edges to earn Class 2 ratings. ANSI Z359.14 also sets rules for labeling, inspection, and proper use so that employers and workers can identify compliant equipment. By following this standard, manufacturers ensure SRLs meet a consistent safety benchmark, and employers can choose devices that provide proven, reliable protection against falls.

Frequently Asked Questions

How Do Self-Retracting Lifelines Work?

An SRL extends and retracts as you move, keeping the lifeline taut. If you fall, it locks instantly and limits the distance.

How Does a Self-Retracting Lifeline Protect You During a Fall?

It arrests the fall quickly and uses an internal brake or energy absorber to reduce the impact on your body.

How Long are Self-Retracting Lifelines Good for? Do They Expire?

SRLs don’t have a set expiration date. They remain in service if they pass required inspections and follow the manufacturer’s guidelines.

What is the Maximum Length for a Self-Retracting Lifeline?

Lengths vary. Personal SRLs may be 6 to 9 feet, while block SRLs and rescue models can exceed 60 feet. SRLs typically range from 60 to 120 feet, though some examples extend to 180 feet.

What is the Maximum Weight a Self-Retracting Lifeline Can Support During a Fall?

Most SRLs are rated for users up to 310 lbs., including tools and gear. Some models support up to 420 lbs.

Why Would a Worker Use a Self-Retracting Lifeline When Working from Heights?

SRLs combine mobility and safety. They allow workers to move freely while ensuring fast fall arrest if a fall occurs.

Why Safety Pros Choose FallTech for SRL Fall Protection?

 

FallTech builds fall protection you can trust. Tested in our ISO-rated lab, our self-retracting lifelines and safety systems meet ANSI and OSHA standards—and we publish every test online. More than equipment, we provide expert guidance, fast answers, and custom solutions, treating your safety concerns like our own.

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