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Environmental Health and Safety

Control of Hazardous Energy Sources (Lockout/Tagout Program)



V. DEFINITIONS


Activation/Energization
setting machinery into motion by starting, switching, pushing, moving, or otherwise engaging power sources for the equipment.

Affected Employees
are those who meet either of the following criteria: (a) their jobs require them to operate, repair, clean, or service equipment that is subject to lockout/tagout; or (b) their jobs require them to work in areas where lockout/tagout is used to provide protection.

Authorized Employees
are those affected employees who are authorized to physically lock or tag out a piece of equipment. An authorized employee and an affected employee may be the same person when the affected employee’s duties also include performing maintenance or repair of a machine or equipment which must be locked or tagged out.

Capable of Being Locked Out
an energy isolating device that is designed with a hasp or other attachment or integral part to which a lock can be affixed, has a locking mechanism built into it, or if a lock out can be achieved without the need to dismantle, rebuild, or replace the energy isolating device or permanently alter its energy control capability.

Energy Control Procedures
the use of lockout/tagout equipment to ensure safe work practices.

Energy Isolating Device
a mechanical device that physically prevents the transmission or release of energy, including but not limited to the following: A manually operated electrical circuit breaker; 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 independently; a line valve; a block; and any similar device used to block or isolate energy. For purposes of this program, on-off switches, selector switches, and push buttons are not considered isolating devices which if “locked out” would provide assurance that the system could not be energized. Whenever major replacement, repair, renovation, or modification of machines is performed and whenever new machines are installed energy isolating devices for the machines shall be designed to accept a lockout device.

Energy Source
is any electrical, mechanical, pneumatic, hydraulic, thermal, chemical, water, gas, steam, or other system that could cause injury to personnel.

Hazardous Motion
the motion of equipment under mechanical stress or gravity that may abruptly release and cause injury.

Hot Tap
is a procedure used to repair equipment. It involves welding on a piece of equipment under pressure in order to install connections. This procedure is commonly used to add equipment without the interruption of service for air, gas, water, and steam distribution systems.

Knowledgeable Individual
is an individual who is qualified to operate the controls or equipment and is familiar with the effects of operation.

Lockout
is used to describe the process of installing a lock on an energy-isolating device, such as a circuit breaker, disconnect switch, or shut-off valve, in accordance with a prescribed procedure, so that the equipment or machine that it controls cannot be activated until the device is removed.

Prime Mover
power driven machinery and equipment.

Tagout
the process of attaching a sign or label to an isolating device in order to warn others not to restore energy to the system or equipment bearing the label. The practice of using tags is usually done in conjunction with locks to increase the visibility and awareness that equipment is not to be energized or activated until such devices are removed.

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This page last updated May 21, 2008
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