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Lock-Out / Tag-Out

Anyone having to service, adjust, repair, or maintain machinery or equipment may be in grave danger of injury unless it is certain that such machinery and equipment is stopped, de-energized, and cannot be started, re-energized, or otherwise activated during the time such work is being done. It is therefore vital that such machinery and equipment be put into a state in which the possibility of its making any unexpected movement, and thus causing injury to those exposed to such movement, is prevented. The procedure most commonly recognized for this purpose is called "lockout," or "tagout." Basic principles and techniques of lockout have been outlined in the authoritative safety literature and various associated standards for decades.

Proper lockout procedures are not complex, but neither are they intuitive. Workplace management must establish mandatory lockout/tagout policies and procedures, properly train all supervisors and workers regarding the requirement to adhere to such procedures, and strictly enforce their use.

In 1937, the National Safety Council published a Safety Practices Pamphlet (No. 70) for "Maintenance and Repair Men" in which they advocated that (a) no repair work should be started on machinery in motion. Before beginning work, it should be absolutely ascertained that the power cannot be turned on, and stating that (b) many members of the National Safety Council make it a practice to lock the controlling device, preferably by padlock, the key to which is kept by the repairman himself, while (c) other companies have place signs or tags on such machines and prohibit their removal until the supervisor has checked the repairs and OK’d the machine for further use, however, (d) the only safe way is for each repairman to lock, with his own padlock, the switchbox or other connecting device so that no one else can tamper with it.

In 1966, the National Safety Council published, "The ABC’s of Lockouts" (National Safety News, March 1966), in which the following points were made:

While the above remains good practice consistent with current recommendations, see the National Safety Council at and search "lockout" for current programs and publications.

The Department of Labor (OSHA) has also adopted federal requirements (regulations) the require the use of lockout practices in general industry under 29 CFR 1910, Subpart J, 1910.147 titled The Control of Hazardous Energy (Lockout/Tagout) and in construction under 29 CFR 1926, Subpart K, 1926.417 titled "Lockout and Tagging of Circuits" at (click on "Regulations" and then Parts 1910 and 1926).

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