Safety Matters: Lockout/Tagout

OSHA estimates that the federal lockout/tagout standard, 29 CFR 1910.147, saves 122 lives and prevents 28,000 lost workday injuries each year.


What it means

The federal lockout/tagout standard, 29 CFR 1910.147, published by the Occupational Safety & Health Administration (OSHA), went into effect in 1989. It was designed to prevent injuries and deaths caused by accidental start-up of equipment during maintenance or servicing. OSHA estimates that the standard saves 122 lives and prevents 28,000 lost workday injuries each year.

The lockout/tagout standard requires that hazardous energy sources be "isolated and rendered inoperative" before maintenance or servicing work can begin. These energy sources include electrical, pneumatic, hydraulic, mechanical, thermal, chemical, and the forces of gravity.

In order to isolate and render inoperative an energy source, an energy-isolating device (circuit breaker, slide gate, line valve, or disconnect switch) must be locked in place, or in certain cases, labeled with a tag warning against start-up of the equipment until servicing is finished. Stored energy sources, such as pressure, springs, and electricity contained in capacitors, must be released or otherwise rendered safe before servicing the equipment. For complex equipment with many energy sources a group lockout is permitted. Each authorized employee performing the maintenance procedure will be protected by his/her own lockout or tagout device to ensure protection.

A lockout device is a lock, either key or combination type, that will hold an energy-isolating device in a safe position. It must be substantial enough to prevent removal without the use of excessive force. A tagout device is a tag with a means of attachment that can be securely fastened to prohibit a machine or equipment from being operated.

After locks are applied, an attempt to restart the equipment must be made to verify the equipment cannot be restarted before servicing begins. After servicing, each person who placed a lock or tag must remove it before the equipment is started and returned to service.

The standard

OSHA requires three basic elements in a lockout/tagout program. These are training, written procedures, and inspections. Training is required for two types of people - "authorized employees" and "affected employees." Authorized employees are people who do the maintenance or servicing work. They are the people who actually perform the lockout/tagout. Affected employees are people who may be affected by or work near equipment which is locked or tagged out. Affected employees are not permitted to perform servicing or maintenance work which requires a lockout or tagout. Retraining should occur whenever there is a change in job assignments, equipment, processes, or energy control procedures.

Written procedures describing the lockout/tagout procedure are required for equipment having two or more energy sources. Many companies require written procedures for every piece of equipment, even those with only one energy source. Written procedures identify energy sources, provide step-by-step instruction for locking or tagging out energy, releasing stored energy, and verifying the equipment cannot be re-started after lockout is applied. Group lockout/tagout procedures must also be clearly documented. Procedures must be kept up-to-date, and changes must be communicated to everyone who may be affected by them.

Lockout/tagout inspection programs must be performed annually. The standard specifies who may perform the inspection. Typically it is an authorized employee who is not directly involved with the procedure being inspected. Periodic inspections provide an opportunity to verify that procedures are being followed and to correct any deficiencies. If you are aware of any problems with the lockout/tagout program don't wait for a routine inspection, report them immediately.

Training and supplies

After becoming more familiar with the OSHA standard you might want additional information and supplies. Safety tags, labels, padlocks, and training programs and kits are available from several companies.

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