Lockout Tagout - Energy Control

Lockout tagout refers to the energy control practice and procedure of safeguarding workers from the unexpected startup of machinery and equipment, by preventing the uncontrolled release of hazardous energy during service or maintenance. In the United States, lockout tagout is governed by OSHA Reg. 29 CFR 1910.147 and in Canada, it is governed by CSA Z460.

These standards, in part, designate that workers turn off and disconnect electrical equipment from its source of energy before performing service or maintenance work. Only an authorized employee can either lock or tag by means of an energy-isolating device (usually a physical lock) to prevent the release of hazardous energy when there is an unexpected startup. Also, the worker must take steps to verify that the energy has been effectively isolated . Employers are responsible for the implementation of these standards, through the development of lockout tagout programs and procedures. If the potential exists for the release of hazardous stored energy, the employer must ensure that workers take steps to prevent injury or death.

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There is a difference between lockout tagout devices.

Lockout Devices

Lockout devices are designed to keep energy-isolation devices in a safe or “off” position. They provide physical protection by preventing machines or equipment from becoming energized because they are positive restraints that no one can remove without a key or other unlocking mechanism, or through extraordinary means, such as bolt cutters.

Tagout Devices

Tagout devices are easier to remove and, by themselves, provide affected employees with less protection than do lockout tagout devices.

Uncontrolled energy is a hazard to operators and other employees in the area of the machinery, equipment or processes. Those who service and maintain machinery or equipment are especially vulnerable because it might become energized while being serviced.

During 1982–2021, NIOSH investigated 231 fatalities related to installation, maintenance, service or repair tasks on or near machines, equipment, processes or systems. According to OSHA, approximately 39 million workers are protected by its lockout tagout standard. (The 3 million workers who actually service equipment—i.e., craft workers, machine operators and laborers—face the greatest risk). OSHA estimates that compliance with the standard prevents about 122 fatalities, 28,400 lost workday injuries and 31,900 non-lost workday injuries each year.

OSHA estimates that adherence to the requirements of this standard can eliminate nearly 2 percent of all workplace deaths in establishments affected by this rule and can have a significant impact on worker safety and health in the United States.

Forms of Hazardous Energy
Workers may be exposed to hazardous energy in several forms and combinations during installation, maintenance, service or repair work. A comprehensive hazardous energy control program should address all forms of hazardous energy:

  • Kinetic (mechanical) energy in the moving parts of mechanical systems;
  • Potential energy stored in pressure vessels, gas tanks, hydraulic or pneumatic systems, and springs (potential energy can be released as hazardous kinetic energy);
  • Electrical energy from generated electrical power, static sources or electrical storage devices (such as batteries or capacitors); and
  • Thermal energy (high or low temperature) resulting from mechanical work, radiation, chemical reaction or electrical resistance.

Servicing and/or Maintenance Operations
If a servicing activity—such as lubricating, cleaning or unjamming the production equipment—takes place during production, the employee performing the servicing may be subjected to hazards that are not encountered as part of the production operation itself. Workers engaged in these operations are covered by lockout tagout when any of the following
conditions occur:

  • The employee must either remove or bypass machine guards or other safety devices, resulting in exposure to hazards
  • at the point of operation;
  • The employee is required to place any part of his or her body in contact with the point of operation of the operational machine or piece of equipment; or
  • The employee is required to place any part of his or her body into a danger zone associated with a machine operating cycle.

OSHA also recognizes that some servicing operations must be performed with the power on. Making many types of fine adjustments, such as centering the belt on conveyors, is one example. Certain aspects of troubleshooting, such as identifying the source of the problem as well as checking to ensure that it has been corrected, is another. OSHA requires the employer to provide effective protection when employees perform such operations. Although, in these cases, a poweron condition is essential either to accomplish the particular type of servicing or to verify that it was performed properly, lockout tagout procedures are required when other service or maintenance occurs and power is not required.

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