Affected employee: An employee, such as a machine or equipment operator, who is required to use machines or equipment serviced or maintained under lockout or tagout, or who performs other job responsibilities in an area where such servicing or maintenance is performed. An affected employee becomes an authorized employee when that employee’s duties include performing servicing or maintenance covered under the lockout/tagout standard.

Authorized employee: An employee who locks out or tags out machines or equipment to perform servicing or maintenance on those machines or that equipment. Any employee who performs one or more procedural elements of an employer’s energy-control program for the purpose of servicing or maintenance is considered an authorized employee.

Capable of being locked out: One of the two categories of energy-isolating device. An energy-isolating device is considered capable of being locked out if it:

• Has a hasp or other means of attachment to or through which a lock can be affixed;
• Has a locking mechanism built in; or
• Can be locked without being dismantled, rebuilt, replaced, or permanently altered in its energy-control capability.

Energized: Of machinery or equipment, connected to an energy source or containing residual or stored energy.

Energy-isolating device: A mechanical device used to physically prevent 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 a circuit’s conductors can be disconnected from all ungrounded supply conductors and no pole can be operated independently,
• A line valve;
• A block; and
• Any similar device used to block or isolate energy. Excluded are push buttons, selector switches, and other control circuit type devices.

Energy source: Any source of electrical, mechanical, hydraulic, pneumatic, chemical, thermal, or other type of energy.

Hot tap. A procedure used in repair, maintenance, and servicing that involves welding on a piece of equipment (such as a pipeline, vessel, or tank) under pressure to install connections or appurtenances. It is commonly used to replace or add sections of pipeline without the interruption of service for air, gas, water, steam, and petrochemical distribution systems.

Lockout: The placement of a lockout device on an energy-isolating device, in accordance with an established procedure, ensuring that the energy-isolating device and the machine or equipment being controlled cannot be operated until the lockout device is removed.

Lockout device: Any device that uses positive means, such as a lock, to hold an energy-isolating device in a safe position, thereby preventing the energizing of machinery or equipment. Included are blank flanges and bolted slip blinds.

Other employees: All employees who are or may be in an area where energy-control procedures may be used.

Normal production operations: The use of a machine or equipment to perform its intended production function.

Servicing and/or maintenance: Workplace activities such as constructing, installing, setting up, adjusting, inspecting, modifying, and maintaining and/or servicing machines or equipment. These activities include lubrication, cleaning or unjamming machines or equipment, and making adjustments or tool changes, where employees could be exposed to the unexpected energization or startup of the equipment or release of hazardous energy.

Setting up: Any work performed to prepare a machine or equipment to perform its normal production operation.

Tagout: The placement of a tagout device on an energy-isolating device, in accordance with an established procedure, to indicate that the energy-isolating device and the machine or equipment being controlled may not be operated until the tagout device is removed.

Tagout device: Any prominent warning device, such as a tag and a means of attachment, that can be securely fastened to an energy-isolating device to indicate that the machine or equipment to which it is attached may not be operated until the tagout device is removed.