What is Lockout / Tagout?

Lockout-Tagout (LOTO) or lock and tag is a safety procedure which is used in industry and research settings to ensure that dangerous machines are properly shut off and not started up again prior to the completion of maintenance or servicing work. It requires that hazardous power sources be "isolated and rendered inoperative" before any repair procedure is started. "Lock and tag" works in conjunction with a lock usually locking the device or the power source with the hasp, and placing it in such a position that no hazardous power sources can be turned on. The procedure requires that a tag be affixed to the locked device indicating that it should not be turned on.


When two or more subcontractors are working on different parts of a larger overall system, the locked-out device is first secured with a folding scissors clamp that has many padlock holes capable of holding it closed. Each subcontractor applies their own padlock to the clamp. The locked-out device cannot be activated until all workers have signed off on their portion of the project and removed their padlock from the clamp.


In many countries, a lock selected by color, shape or size (e.g. red padlock) is used to designate a standard safety device, locking and securing hazardous energy. No two keys or locks should ever be the same. A person's lock and tag must not be removed by anyone other than the individual who installed the lock and tag unless removal is accomplished under the direction of the employer. Employer procedures and training for such removal must have been developed, documented and incorporated into the employer's energy control program


The more common industrial regulations include :


  • OSHA 29 CFR 1910.147—The control of hazardous energy (LOTO)

  • ANSI Z244.1—Control of hazardous energy—LOTO & Alternative methods: All energy isolating devices should be adequately labeled or marked.

  • EU Provision of Work Equipment regulation 19—Isolation from Sources of energy: Every employer shall ensure that where appropriate, work equipment is provided with suitable means to isolate it from all its sources of energy.

  • EU guidelines 89/655 paragraph 2.14: every piece of equipment must be fitted with clearly visible devices with which it can be separated from every energy source.

  • MOM's Workplace Safety & Health Act 2006 (Act 7 Part III)


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