Lockout/Tagout

Scope

The principles and requirements for lockout/tagout apply to most employers whose workers perform maintenance on equipment where the uncontrolled release of hazardous energy, such as kinetic, pneumatic, chemical, electrical, or thermal, is possible, or are exposed to such hazards from the maintenance.

Regulatory citations

• 29 CFR 1910.147 — The control of hazardous energy (lockout/tagout). The control of hazardous energy is also addressed in a number of other OSHA standards, including electrical (Part 1910 Subpart S) and electric power generation, transmission and distribution (Part 1910 Subpart R).

Key definitions

• Authorized employee: An employee who locks or tags machines or equipment in order to perform servicing or maintenance.
• Affected employee: An employee who is required to use machines or equipment on which servicing is performed under the Lockout/Tagout standard or who performs other job responsibilities in an area where such servicing is performed.
• Capable of being locked out: An energy-isolating device is considered capable of being locked out if it: (a) is designed with a hasp or other means of attachment to which a lock can be affixed; (b) has a locking mechanism built into it; or (c) can be locked without dismantling, rebuilding, or replacing the energy-isolating device or permanently altering its energy control capability.
• Energized: Machines and equipment are energized when they are connected to an energy source or they contain residual or stored energy.
• 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. Push buttons, selector switches and other control circuit type devices are not energy isolating devices.
• Energy source: Any source of electrical, mechanical, hydraulic, pneumatic, chemical, thermal, or other energy.
• 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 equipment being controlled cannot be operated until the lockout device is removed.
• Lockout device: Any device that uses positive means, such as a lock, blank flanges and bolted slip blinds, to hold an energy-isolating device in a safe position, thereby preventing the energizing of machinery or equipment.
• Normal production operations: Utilization of a machine or equipment to perform its intended production function.
• Other employees: All employees who are or may be in an area where energy control procedures may be utilized.
• Servicing and/or maintenance: Workplace activities such as constructing, installing, setting up, adjusting, inspecting, modifying, maintaining and/or servicing machines or equipment, including lubrication, cleaning or unjamming of 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.
• 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 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.

Summary of requirements

The standard establishes requirements that employers must follow when employees are exposed to hazardous energy while servicing and maintaining equipment and machinery. Some of the most critical requirements from the standard are outlined below:

• Develop, implement, and enforce an energy control program.
• Use lockout devices for equipment that can be locked out. Tagout devices may be used in lieu of lockout devices only if the tagout program provides employee protection equivalent to that provided through a lockout program.
• Ensure that new or overhauled equipment is capable of being locked out.
• Develop, implement, and enforce an effective tagout program if machines or equipment are not capable of being locked out.
• Develop, document, implement, and enforce energy control procedures.
• Use only lockout/tagout devices authorized for the particular equipment or machinery and ensure that they are durable, standardized, and substantial.
• Ensure that lockout/tagout devices identify the individual users.
• Establish a policy that permits only the employee who applied a lockout/tagout device to remove it.
• Inspect energy control procedures at least annually.
• Provide effective training as mandated for all employees covered by the standard.
• Comply with the additional energy control provisions in OSHA standards when machines or equipment must be tested or repositioned, when outside contractors work at the site, in group lockout situations, and during shift or personnel changes.