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Lockout Tagout Systems and Standards

Quick Tips #170

The Lockout/Tagout Standard, 29 CFR 1910.147, was launched Oct. 30, 1989, to help reduce worker death and injury rates.

The standard covers machine and equipment maintenance and service over which the unexpected energization, start-up or release of stored energy could cause injury [29 CFR 1910.147 (a)(l)(i), 1910.147 (a)(2)(i)]. Normal production operations, cords and plugs under exclusive control, and hot tap operations are not covered [29 CFR 1910.147 (a)(2)(ii),  (a)(2) (iii)(A)]. The rules do apply to electrical, mechanical, hydraulic, chemical and thermal energy sources among others.

Lockout devices—such as circuit breakers, slide gates, line valves and disconnect switches—ensure that an energy-isolating device cannot be used until the lockout device is removed. A lockout device uses a positive means, such as a key or combination lock, to hold an energy-isolating device in a safe position and prevent machine or equipment energization. The lockout device must be substantial enough to prevent removal without excessive force or unusual techniques.

Tagout devices, such as tags or other prominent warning devices, indicate that an energy-isolating device and its equipment must not be used until the tagout device is removed.

A lockout device must be used unless the employer can demonstrate that a tagout system would provide full employee protection. The tagout device must be nonreusable, attached by hand, self-locking and nonreleasing with a minimum unlocking strength of 50 pounds, and must be at least the equivalent of an all-environment tolerant nylon cable tie.

Written Program

OSHA 29 CFR 1910.147 (c)(4) covers the minimal acceptable written program procedures. A written program must include:

  1. A specific written statement of the intended use of the procedure.
  2. Specific procedural steps taken for shutting down, isolating, blocking and securing machines or equipment to control hazardous energy. This must be done for each piece of equipment unless it is a duplicate.
  3. Specific procedural steps for placing, removing and transferring lockout devices and the responsibility for them.
  4. Specific requirements for testing lockout devices, tagout devices and other energy-control measures.

Authorized employees shall be provided worker training [29 CFR 1910.147 (c)(7)(I)]. Training must include the energy-control procedure uses and purposes, and all workers in the area where the energy-control procedures are used. When tagouts are used, employees must be taught of the devices' limitations. All employees must be retrained whenever job assignments, machines, equipment or processes change or present new hazards.

Lockout / Tagout Device Removal

Before lockout or tagout devices are removed, authorized employees must ensure that nonessential items are removed and machine components are operationally intact. The area should be checked to ensure that all employees are safely positioned or removed and that all affected employees are notified that lockout/tagout devices have been removed. The person who applied the lockout/tagout device must be the person who removes the device. If the person who applied the device is not available, another employee may remove the device if the employer has established a specific procedure and training for it. When group lockout/tagout devices are used, a procedure equal to the personal lockout/tagout system should be followed. [(29 CFR 1910.147 (f)(3)]

Commonly Asked Questions
Q.   Can I use a tagout instead of a lockout when it is impossible to lock out?
A.   When it is impossible to lock out, or in industries where tag use has been well established and accepted as a recognized prohibitive to the operation of energy-isolating devices, a tagout procedure is acceptable.
Q.   Do I have to lockout/tagout a machine that only requires the unit to be unplugged?
A.   No. The standard does not apply in situations where work on cord-and-plug-connected electric equipment is under the exclusive control of the employee performing the servicing or maintenance.
Q.   Are there any other standards related to lockout/tagout?
A.   Yes. OSHA can use 29 CFR 1910.212, General Requirements for All Machines, and 29 CFR 1910.219, Mechanical Power Transmission Apparatus, to cite businesses for a lack of compliance. These two areas also allow OSHA to issue a double citation for noncompliance.



29 CFR 1910.147, 1910.212 and 1910.219.

ANSI Z244.1-2003, Personal Protection Lockout/Tagout of Energy Sources.

American National Standards Institute (ANSI)
11 W. 42nd St.
New York, NY 10036

Seim, B., Beutler, W., "Ancillary Safety Interlocks Enhance Conventional Lockout/Tagout Procedures," Occupational Health and Safety, October 1993, pp. 47--50.

Occupational Safety and Health Reporter, Jan. 13, 1994, p. 973.

(Rev. 5/2014)

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Please Note:
The content in this newsletter is intended for general information purposes only. This publication is not a substitute for review of the applicable government regulations and standards, and should not be construed as legal advice or opinion. Readers with specific compliance questions should refer to the cited regulation or consult with an attorney.

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