What is Lockout Tagout

By R.W. Hurst, Editor

What is Lockout Tagout?
Lockout Tagout is defined as the "placement of a lockout device on an energy-isolating device in accordance with an established procedure." A lockout device is "a mechanical means of locking that uses an individually keyed lock to secure an energy-isolating device in a position that prevents energization of a machine, equipment, or a process."

Hazardous Energy sources can be:

  • Electrical
  • Mechanical
  • Pneumatic
  • Hydraulic

The most effective Lockout Tagout (LOTO) practices and procedures are ones that safeguard electrical workers from electrical hazards, accidents, injuries and death from the unexpectded startup of a piece of equipment. The OSHA standard for The Control of Hazardous Energy (Lockout/Tagout)  outlines the various measures employers and workers can take when controlling different types of hazardous electrical energy. The OSHA  standard (29 CFR 1910.147) establishes a company's responsibility for protecting electrical workers. All employers are required by OSHA to train each electrical worker and make sure that workers both know and understand and are able to follow the correct provisions of Lockout Tagout procedures:

Proper lockout/tagout (LOTO) practices and procedures safeguard workers from the release of hazardous energy. The OSHA standard for The Control of Hazardous Energy (Lockout/Tagout) (29 CFR 1910.147) for general industry, outlines specific action and procedures for addressing and controlling hazardous energy during servicing and maintenance of machines and equipment. Employers are also required to train each worker to ensure that they know, understand, and are able to follow the applicable provisions of the hazardous energy control procedures. Workers must be trained in the purpose and function of the energy control program and have the knowledge and skills required for the safe application, usage and removal of the energy control devices. Employers are also responsible for the retraining of all electrical workers to maintain their proficiency in LOTO.


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LOTO Explained
Lockout is one of the best ways to control hazardous energy. Lockout involves the isolation of energy from the system, whether it be a machine, electrical equipment or process, which physically locks the system and places it into safe mode. Such energy-isolating devices can be a manually operated disconnect switch, a circuit breaker, a line valve, or a block. Often, these energy-isolating devices will have loops or tabs which can lock a stationary item in a safe, de-energized position. The lockout device can be any device that has the ability to secure the energy-isolating device in a safe position.

Tagout is a term used for a labelling process that is always attached to equipment when lockout is required. When a tagout device is used on an energy-isolating device which is able to be locked out, it MUST be attached at the SAME location as the Lockout device would be AND demonstrate the equivalent level of safety to the LOTO program. The process of tagging out hazardous equipment involves attaching an information tag or indicator (usually a standardized label) that includes the following tagout information:


Why LOTO is required.

  • Time and date of placement of the lock and tag
  • Name of the authorized person who attached the lock and tag


Note: ONLY the authorized person who attached the lock and tag is permitted to remove them. This makes sure that the system cannot be energized without the authorized person's knowledge.

LOTO Placement

Lockout is the placement of a lock device on an energy-isolating device to ensure the equipment cannot be operated during equipment maintenance or repair.

Tagout is the placement of a tag device on an energy-isolating device to warn of the danger of operating and TO NOT start the equipment until the tag is properly removed.

THE ULTIMATE GOAL IS:  To implement policies and procedures to prevent, as necessary, the release of hazardous energy from power sources--or from a stored source in machines, equipment or processes.

Release from Lockout Tagout

A release from LOTO can only occur when:

The work area has been inspected to ensure that nonessential items have been removed and the equipment components are intact.

The work has been checked to ensure that all employees have been safely positioned or removed.

LOTO devices can ONLY be removed by the authorized employee who placed the device, or under the direction of the employer, if the authorized employee is unavailable.


Affected Employees
Any worker whose job requires them to operate/use or be in the area of machinery or equipment on which service/maintenance is being performed.

Authorized Employees
The person who is responsible for the LOTO of machinery or equipment.

Lockout Device
A device such as a lock (key or combination) that holds/secures an energy-isolating device, thus preventing an energy source from operating.

Tagout Device
A prominent warning device, such as a tag with a means of attachment, which can be securely fastened to an energy-isolating device.


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