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 9-01-2004

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, failure to implement any recommendations

in this Safety and Health Information 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.

Purpose

The purpose of this Safety and Health Information Bulletin is:

1. to remind employers and employees that

personal fall arrest systems used in

construction must meet the provisions of 29

CFR 1926.502 (d), and positioning device

systems must meet the provisions of 29 CFR

1926.502 (e);

2. to alert users that they must follow the

manufacturers’ instructions regarding the

intended use of wire form1 anchorage

connectors; and

3. to provide recommendations for employers

and employees using the wire form anchorage

connectors.

Background

The OSHA Bismarck Area Office investigated

a fatal accident involving a spring-loaded wire form

anchorage connector that was used in communication towers upgrade work. This anchorage connector is opened by compressing the two lower wires

of the anchorage connector. On many wire form

anchorage connectors, the top portion will open to

form double hooks with an opening of 3-1/8” for a

small connector and up to 5-1/2 ” opening for a

large connector (Figure 1). The hooks are then

connected to an anchorage (a secure means of

attachment) as part of a personal fall arrest system

or a positioning device system (Figure 2). The wire

form anchorage connector is used frequently in the

tower construction and maintenance industry as a

Hazards of Misusing Wire Form Anchorage

Connectors for Fall Protection

 1These wire form anchorage connectors have the following

names: Wire Anchorage Connector, Wire Form Pipe Hook, Wire

Hook Anchorage Connector, and Wire ClaspTM.

Figure 1

Spring-loaded Wire Form Anchorage Connector
Accident Description

A communication tower erection and

maintenance company employee was using a wire

form anchorage connector while upgrading the

structural members on a broadcasting tower. After

completing work at the 65-foot level, the employee

Figure 2

mechanism of the anchorage connector, resulting in

an unintentional disengagement of the connector and

permitting the employee to fall approximately 75 feet

to the ground. The employee died as a result of the

fall.

portable/temporary anchorage connector for

personal fall arrest systems and for positioning

device systems.

climbed to the 75-foot working level and connected

the anchorage connector to a diagonal member of

the tower. The employee also was wearing a

personal fall arrest system. However, instead of

connecting his personal fall arrest system directly to

an anchorage, the employee used the wire form

anchorage connector connecting assembly as a

personal fall arrest system. When attached to the

diagonal member, the anchorage connector was

positioned in a manner such that, in the event of a

fall, the employee’s weight would exert a significant

side load on the anchorage connector - a condition

that the wire form anchorage connector is not

designed to handle.

While moving back to his working position,

the anchorage connector became lodged between a

diagonal member and a horizontal member of the

tower. Although the exact cause of the accident

may never be definitively determined, the position of

the anchorage connector between the diagonal and

horizontal members and the weight of the falling

employee may have exerted a force on the release

Other Information

The specifications and limitations for the wire form

anchorage connector, as provided by a major

manufacturer, are as follows:

Specifications:

• The anchorage connectors meet OSHA

requirements and ANSI Z 359.1 provisions.

• The anchorage connector has a minimum

breaking strength of 5000-pound force

(22.2 kN).

• The anchorage connectoris designed for the

attachment of a single personal fall arrest

system.

• The anchorage connectoris for one person

with a capacity of 310 pounds (140 kg)

including weight of the user plus clothing,

tools, and other user-borne objects.

• When the anchorage connector is used as

part of a personal fall arrest system, the fall

arresting force must not exceed 1,800-

pound force (8 kN).

Limitations and Cautions:

• Select only anchorages of suitable size,

strength and shape for use with the anchorage connector.

• The connecting hardware to the anchorage

connector also must be compatibly designed

in size, shape, and strength.

• Always connect to a suitable overhead

anchorage. The anchorage connectors

are designed to hook onto structures

directly above the worker.

• Do not apply a side load to the anchorage connector.
2

Some of the other OSHA standards that have fall protection

provisions include: 1910.66, 1910.132, 1910.268, 1910.269,

Subpart D of the general industry standards, 1915.159, 1915.160,

1915.161, 1918.85, 1926.104, 1926.451(g), and 1926.760.

3

Double locking devices - such as large snaphooks, rebar hooks,

or pelican hooks and tie-back type shock-absorbing lanyards --

may be used in lieu of wire form anchorage connectors as

components of the connection assembly for postioning device

systems and personal fall arrest systems. However, as with wire

form anchorage connectors, employers need to review the

manufacturer’s user instructions for these devices and only use

the devices in a manner that conforms to the manufacturer’s

instructions and use limitations. In addition, employers must

comply with OSHA regulations applicable to the use of such

devices.

29 CFR 1926.502 (d), contains requirements

for Personal fall arrest systems.

29 CFR 1926.502 (e), contains requirements

for Positioning device systems.

OSHA recommends that contractors and

other employers review OSHA’s requirements for

the use of personal fall arrest systems and positioning device systems. Employers must only use

personal fall arrest system connectors and positioning device system connectors that meet applicable

OSHA regulations.

Employers must train employees on the

appropriate use of personal fall arrest systems and

positioning device systems and ensure that such

systems are connected only to compatible components. Contractors and other employers should

review manufacturer instructions and markings and

must ensure that the wire form anchorage connector

is the appropriate anchorage connector3 for the

situation and work environment in which it will be

used.

Requirements and Recommendations

OSHA’s construction standard for fall protection system criteria and practices 29 CFR

1926.502.2

• The potential fall arrest loads must be

applied vertically to, and directly below, the

anchorage connector.

• Avoid contact with nearby objects that

could come into contact with the anchorage

connector and cause interference with its

intended use.

• Remove from service and destroy if an

anchorage connector has been subjected to

the forces of arresting a fall.

Conclusions

The wire form anchorage connector was a

component of the connecting assembly for a personal fall arrest system as used in the incident

described above. Its connection to a diagonal

member of the tower was contrary to a major

manufacturer’s user instructions, which caution that

the anchorage connector is not designed to support

side loads and that installation must be planned so

that potential fall arrest loads are applied vertically

to, and directly below, the anchorage connector.

The user instructions also provide that anchorage

connector and anchorage point should be located a

safe distance from any obstacles, and the anchorage

connector should not come into contact with nearby

objects.

In the situation described above, the movement

of the anchorage connector to a non-vertical position between a horizontal and diagonal member of

the tower likely resulted in the anchorage connector

coming into contact with nearby objects. This

movement may have resulted in a side load when the

employee fell, which may have exerted force on the

release mechanism of the anchorage connector, thus

possibly permitting the disengagement of the anchorage connector.