U. S. Department of Labor

Occupational Safety and Health Administration

Directorate of Science, Technology and Medicine

Office of Science and Technology Assessment

Safety and Health Information Bulletin

SHIB 03-09-22

This Safety and Health Information Bulletin is not a

standard or regulation, and it creates no new legal

obligations. The Bulletin is advisory in nature,

informational in content, and is intended to assist

employers in providing a safe and healthful workplace. The Occupational Safety and Health Act

requires employers to comply with hazard-specific

safety and health standards. In addition, pursuant to

Section 5(a)(1), the General Duty Clause of the Act,

employers must provide their employees with a

workplace free from recognized hazards likely to

cause death or serious physical harm. Employers

can be cited for violating the General Duty

Clause if there is a recognized hazard and they

do not take reasonable steps to prevent or abate

the hazard. However, the failure to implement any

recommendations contained in this Safety and

Health Bulletin is not, in itself, a violation of the

General Duty Clause. Citations can only be based

on standards, regulations, and the General Duty

Clause.

Compatibility of Personal Fall Protection System Components

Purpose

The purpose of this safety and health

information bulletin is to alert users of personal

fall protection systems that:

1. Personal fall protection components

made by different manufacturers may not

be compatible. Components made by the

same manufacturer also may not be

compatible if they are not sized properly;

2. In some situations, large snap hooks may

be susceptible to roll out; and

3. To remind users of OSHA’s standard on

personal fall arrest systems and its

requirements for snaphooks.

Background

The Methuen Area Office recently investigated an

accident that involved a non-fatal fall of an

ironworker from a steel beam onto the metal

decking below. At the time of the fall, the

ironworker was wearing personal fall arrest

equipment. A 2 1/4 -inch gate snap hook (Figure 1)

on the end of his lanyard was connected to the D

ring on a beamer (a portable anchorage connector

that rolls along the upper or lower flange of the

beam, figures 2 and 3) that was attached to the top

flange of the beam on which he was walking. This

snap hook was the locking type that requires at least

two consecutive, deliberate actions to open. When

the ironworker fell, the snap hook rolled out of its

attachment.

Incident Description

The lanyard and snap hook were owned by the

ironworker and were manufactured by the same

personal fall arrest system manufacturer, while

the beamer that was attached to the beam was

supplied by the ironworker’s employer and was

manufactured by a different fall protection

equipment manufacturer. The worker’s lanyard had

a large hook on one end with a 2 1/4-inch gate.

Apparently, the ironworker did not know that the

snap hook of the personal fall arrest system he was

using was compatible with the beamer’s D ring
2

ONLY when the beamer is attached to an overhead

beam, rather than to the beam on which he was

working.

While working on the cross beam, the

ironworker lost his balance and fell. Due to the

nature of the fall, the snap hook experienced a

side load which caused the hook’s keeper to fail,

and the snap hook rolled out of its attachment. It

is not known whether the side load exceeded the

350 pound side load requirements of ANSI A

10.14 and Z 359.1 standards for the snap keeper.

The ironworker fell to the metal decking 16 feet

below and sustained non-fatal injuries.

OSHA Standards

29 CFR 1926.502(d)(5) states in relevant part, that

“snaphooks shall be a locking type snaphook

designed and used to prevent disengagement of the

snaphook by the contact of the keeper by the

connected member.”

29 CFR 1926.502(d)(6)(v) states “snaphooks shall

not be engaged to any object which is incompatibly

shaped or dimensioned in relation to the snaphook

such that unintentional disengagement could occur

by the connected object being able to depress the

snaphook keeper and release itself.”

ANSI Standard

ANSI A10.14, 1991, American National

Standard for Construction and Demolition

Operations - Requirements for Safety Belts,

Harnesses, Lanyards and Lifelines for

Construction and Demolition Use, paragraph

4.2.2.4, states that “snap-hooks with throat opening

larger than 5/8” (1.6 cm) shall have a label

attached.” The label shall indicate the minimum size

diameter to which the snap-hook shall be attached.1

“The snap keeper shall be retained by the nose of

the snap and shall be capable of withstanding a

minimum 350 pound (159 kg) side load.”

Paragraph 4.2.3.4, states “[t]he snap-hook for

attachment of D-rings and O-rings shall be

designed to minimize the possibility of

accidental disengagement from the D-ring.”

ANSI Z 359.1, 1992, American National

Standard Safety Requirements for Personal Fall

Arrest Systems, Subsystems and Components,

paragraph 3.2.1.4 states “[w]hen tested in

accordance with 4.3.1.1.3, the gate of the

snaphook or carabiner shall be capable of

withstanding a minimum side load of 350

pounds (1.55 kN) applied to a point midway

between the nose and gate hinge without

breaking, permanent deformation greater than

0.125 inches (3.1 mm), or separating from the

nose of the snaphook or carabiner body by more

than 0.125 inches (3 mm).”

Other Information

After the accident, it was learned that both the

lanyard and the beamer manufacturers had stated

that the large snap hook (2 1/4-inch gate opening) on

the lanyard was not compatible with the beamer’s D

ring, unless the beamer is attached to an overhead

beam. The lanyard manufacturer explained that the

snap hook on this lanyard is designed for connection

to large, continuous objects such as horizontal rebar,

horizontal tower bracing or other structural steel that

will not press against the gate of the hook when the

hook rotates, twists or turns.

During the investigation, it was established that

lanyards with this type of large hook are prevalent in

the steel erection industry. They are popular in part

because, given the larger hook’s gate opening, they

offer greater versatility because they can be

connected to a greater number of possible

1 For example on a rebar snap-hook with a 1-5/8" (4.1 cm) throat opening, the warning might read “Warning: Do not

use on attachments less than 1-1/4” (3.2 cm) in diameter.”
3

anchorage points. This lanyard and hook design are

popular not only with employers, but also are

selected by many ironworkers who purchase and

use their own personal fall arrest systems.

Conclusions

Personal fall arrest systems must be designed and

used in accordance with the provisions set forth in

29 CFR 1926.502 (d)(1) through (d)(24).

29 CFR 1926.502(d)(5) & 29 CFR 1926.502

(d)(6)(v) require employers to determine whether

the snaphooks on the personal fall arrest systems

used by their employees are compatible with the

members to which they are connected in order to

prevent unintentional disengagement of the

snaphook. Also, employers must ensure that the

snaphooks on the personal fall arrest systems that

their employees use are not engaged to any object

which is incompatibly shaped or dimensioned in

relation to the snaphook.

OSHA reminds all employers that they must

evaluate the compatibility of all fall arrest systems

and anchorage devices used on the job site before

they are used to protect employees. Employers

should review carefully manufacturer instructions

and warnings, and should be particularly vigilent

when components are manufacturered by different

entities and not sold as a complete system since

such components are more likely to be incompatible

for use together.

Figure 1

Figure 2

Figure 3