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What is Lockout?

Lockout is a practice used to prevent the release of hazardous energy. For example, a safety padlock can be placed on an energy isolating device that is placed in the OFF or Closed position. The term Lockout refers to the principle of correctly shutting down an energy source, draining excess energy that may be present and applying devices to that energy source in order to prevent it from being energised.

Master Lock S2390 Miniature Circuit Breaker Lockout secured by Master Lock 410 Safety PadlockAll workers performing servicing and/or maintenace on equipment and who are exposed to the unexpected energization, start-up or release of hazardous energy.

Lockout in a Nutshell

A lockout device stops equipment from being switched on when it is absolutely crucial that it remains switched off.

Anything that is an energy source is suitable for lockout, as long as that energy source moves machinery and the components within that machinery.

Lockout Definitions

Affected employee. An employee required to operate a machine or piece of equipment on which servicing or maintenance is being carried out under lockout or tagout, or an employee whose job requires that he/she must work in an area in which such servicing or maintenance is being carried out.

Authorized employee. A person who locks out or tags out machines or equipment in order to perform servicing or maintenance on that machine or equipment. An affected employee will become an authorized employee when his/her duties include performing maintenance or servicing covered under this section.

Energy Source Locked Out with Master Lock 410 and tagged with Master Lock 497A Lockout TagCapable of being locked out. An energy isolating device is capable of being locked out if it has a hasp or some other means of attachment to/through which a lock can be attached or if it has a locking mechanism already built into it. Other energy isolating devices are also capable of being locked out if lockout can be achieved without the requirement to dismantle, replace or to rebuild the energy isolating device or to permanently alter its energy control capability.

Energized. Connected to an energy source or containing residual or stored energy.

Energy isolating device. An Energy isolating device is a mechanical device that physically stops the transmission or release of energy. Examples include a manually operated circuit breaker (electrical); a disconnect switch; a manually operated switch (by which the conductors of a circuit can be disconnected from all ungrounded supply conductors), and, in addition, no pole can be operated or run independently; a line valve; a block and any similar device used to block or isolate energy. Selector switches, Push buttons and other control circuit type devices are not energy isolating devices.

Master Lock 484 Gate Valve Lockout secured with two Master Lock 410 PadlocksEnergy source. Any source of electrical, pneumatic, mechanical, hydraulic, thermal, chemical or other energy.

Hot tap. A procedure used in the repair, services and maintenance activities which involves welding on a piece of equipment (pipelines, vessels or tanks) that is under pressure in order to install appurtenances or connections. It is often used to add or replace sections of pipeline without interruption of service for air, water, gas, steam and petrochemical distribution systems.

Lockout. The placement of a lockout device on to an energy isolating device, in accordance with an established process which ensures that the energy isolating device and the equipment being controlled can not be operated until the lockout device has been removed.

Lockout device. A device that utilizes a positive means such as a lock (either key or combination type), to hold the energy isolating device in the safe position and prevent the energizing of equipment or a machine. Included are blank flanges and bolted slip blinds.

Master Lock 418 Safety Hasp secured by 4 colour coded Masterlock 410 Lockout PadlocksServicing and/or maintenance. Workplace activities such as installing, constructing, adjusting, inspecting, modifying, setting up and maintaining and/or servicing machines or equipment. These activities can include cleaning or unjamming of machines or equipment, lubrication and making adjustments or tool changes, where the employee may possibly be exposed to the unexpected energization or startup of the equipment or release of hazardous energy.

Tagout. The placement of a tagout device on an energy isolating device, in accordance with an established procedure, to specify that the energy isolating device and the equipment being controlled can not be operated until the tagout device has been removed.

Tagout device. A prominent warning device, such as a tag and a means of attachment, which can be fastened securely to an energy isolating device in accordance with an established procedure, to indicate that the energy isolating device and the equipment being controlled can not be operated until the tagout device has been removed.

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