Lockout standard safety


For the protection of faculty, students, and staff, the following lockout standard is intended primarily for use when locking and tagging equipment for electrical work. However, the information in this standard applies to all types of power for equipment operation. The aim of a lockout is to establish zero energy state in the machine. Zero energy state means all types of power including electricity, air under pressure, oil or water under pressure, and steam are dissipated so that operation of any controls will not produce movement. Use of power, such as steam under pressure, for heating does not remove it from this category. It is still power, capable of doing injury or damage, and subject to the lockout standard.


When people are working on or near machines or equipment in which the unexpected movement of parts or the charging of electrical conductors would subject them to injury, the following precautions must be taken.


Requirements of regulations for industrial establishments under the Occupational Health and Safety Act of Ontario:


  1. The power supply to electrical installations, equipment or conductors shall be disconnected, locked out of service and tagged before any work is done, and while it is being done, on or near live exposed parts of the installations, equipment or conductors.
  2. Before beginning the work, each worker shall determine if the requirements of subsection (1) have been complied with.
  3. Locking out is not required:
    1. If the conductors are adequately grounded with a visible grounding mechanism
    2. If the voltage is less than 300 volts and there is no locking device for the circuit breakers or fuses and procedures are in place adequate to ensure that the circuit is not inadvertently energized.
  4. If locking out is not required for the reason set out in clause (3b.), the employer shall ensure that the procedures required by that clause are carried out.
  5. If more than one worker is involved in the work referred to in subsection (1), the worker who disconnected and locked out the power supply shall communicate the purpose and status of the disconnecting and locking out.
  6. If a tag is used as a means of communication, the tag:
    1. Shall be made of non-conducting materials
    2. Shall be secured to prevent its inadvertent removal
    3. Shall be placed in a conspicuous location
    4. Shall state the reason the switch is disconnected and locked out
    5. Shall show the name of the worker who disconnected and locked out the switch
    6. Shall show the date on which the switch was disconnected and locked out
  7. The employer shall establish and implement written procedures for compliance with this section.


  1. A part of a machine, transmission machinery, device or thing shall be cleaned, oiled, adjusted, repaired or have maintenance work performed on it only when:
    1. Motion that may endanger a worker has stopped
    2. Any part that has been stopped and that may subsequently move and endanger a worker has been blocked to prevent its movement


  1. Where the starting of a machine, transmission machinery, device or thing may endanger the safety of a worker:
    1. Control switches or other control mechanisms shall be locked out
    2. Other effective precautions necessary to prevent any starting shall be taken

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Hazardous energy is defined as any electrical, mechanical, hydraulic, pneumatic, chemical, nuclear, thermal, gravity, potential or other energy that could cause injury to a person. The aim of this lockout program is to establish a zero energy state in a machine to prevent inadvertent operation, movement or energization of a machine/process in order to protect personnel.


This standard applies to controlling hazardous energy in equipment or processes involving tasks such as, but not limited to:

  • Erecting
  • Installing
  • Constructing
  • Repairing
  • Adjusting
  • Inspecting
  • Unjamming
  • Setting-up
  • Trouble-shooting
  • Testing
  • Cleaning
  • Dismantling
  • Servicing
  • Maintaining

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Associated hazards

Hazards, such as mechanical, electrical, thermal, pneumatic, hydraulic, radiation, residual or stored energy, motion, fuels, and human factors associated with each task shall be identified.

Stored and residual energy

  • When stored or residual energy has been determined to be a hazard in the machine, equipment or process a means of dissipating the energy safely or restraining the stored energy must be determined and be capable of verification.
  • If machinery run-down or coasting is deemed to be a hazard guarding must be installed to protect against the hazard or to prevent access to the hazard until motion has stopped.
  • All physical safeguards, such as pin, blocks, restraints or chains, must be capable of withstanding the forces they are blocking.

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Risk assessment

A risk assessment should be performed for each step involved when developing lockout procedures for a device or process to determine any real or potential hazards that may be encountered during lockout.

Energy isolating devices

  • Machines, equipment or processes utilized at the University of Waterloo must be capable of being locked out through the use of energy isolating devices with consideration being given to the intended use of the machine, equipment or process to control hazardous energies.
  • Energy isolating devices must also be capable of being locked or otherwise secured in an isolating position and be evaluated for its suitability for the machine, equipment or process. 
  • If the machine, equipment or process is composed of several components each component must be capable of being isolated, if they are to be serviced or maintained separately.

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Lockout program

Each department is responsible for:

  1. Determining shut-down, de-energization, energization and start up sequences.
  2. Ensuring a risk assessment has been performed.
  3. Ensuring that personnel are trained in current lockout procedures.
  4. Ensuring that proper lockout procedures are followed with regards to:
    1. Lockout sequence – Appendix A
    2. Lockout and tag removal when individual who applied lockout is absent – Appendix B
    3. Group lockout – Appendix C
  5. For each machine, equipment or process that requires lockout, identify:
    1. The machine, equipment or process
    2. The type(s) of hazardous energy involved
    3. All energy isolating devices
    4. Specific procedural steps for placement and removal of lockout devices
    5. Procedure to verify that isolation and de-energization has occurred
    6. Procedure to verify that all personnel are clear and that the machine, equipment or process is ready for return to use
  6. Providing standardized lockout devices that are:
    1. Uniquely identified
    2. Utilized only for lockout
    3. Are able to withstand the environment in which they are used
  7. Providing information tags to be used with lockout devices that:
    1. Identify the individual that applied the lockout device
    2. Date
    3. Reason for lockout, and
    4. Remain legible and in good shape for the duration of the lockout
  8. Verifying that the lockout procedures are complete and accurate and that hazardous energy is controlled.

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Appendix A

Lockout sequence

  1. Prepare for shutdown
    1. Review appropriate shutdown sequence
    2. Identify hazardous energies to be controlled and hazardous energy control devices
    3. Gather appropriate lockout devices
    4. Identify notification requirements
  2. Notification of affected personnel
  3. Shutdown
    1. Follow proper shutdown procedures for machine, equipment or process
  4. Hazardous energy isolation
    1. Activation of energy isolating devices to bring machine, equipment or process to zero energy state
  5. Application of lockout devices and tags
    1. Lockout devices and tags are to be applied to energy isolating devices to ensure “safe” position is maintained
  6. Control stored energy
    1. All potentially hazardous stored, residual or potential energy shall be:
      • De-energized
      • Relieved
      • Blocked
      • Disconnected
      • Restrained, or
      • Controlled
  1. Verification of isolation
    1. Ensure that hazardous energy has been controlled by trying to start the machine, equipment or process.
  2. Perform work, maintenance, repairs, etc.
  3. Return to service
    1. Before return to service verify that:
      • All individuals associated with the lockout who could be affected by the re-energization have been cleared from the danger zone
      • All non-essential items have been removed and that the machine, equipment or process is operationally intact.
      • Removal of locks from hazardous energy control devices has occurred
      • Personnel that could be affected by the start-up have been notified
      • Re-start the machine, equipment or process

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Appendix B

Lock and tag removal when individual who applied lockout is absent.

Lockout removal form (PDF)

In order to safely remove any lockout devices and tags when the person who applied the devices and tags has departed the workplace the following procedures must be followed.

  1. Verify that the person that placed the lockout devices and tags has left the workplace.
  2. Attempt to contact the person that placed the lockout devices and tags directly (e.g. telephone).
  3. If contacted, that the person that placed the lockout devices and tags is made aware of the situation and requested to come back into the workplace to remove their own locks and tags as required.

If the authorized person assigned the lock and tag cannot be contacted or is not reasonably available to return to the workplace, the appropriate supervisory personnel may authorize the removal of the lock and tags.
If a supervisor-authorized removal is undertaken, the following steps must be performed:

  1. The status and condition of the machine, equipment, or process is assessed and verified to be in a state that will allow for the safe removal of the lockout device.
  2. Provisions are made to ensure that the authorized person will be notified that his/her lock or tag has been removed before resuming work at the workplace.
  3. The appropriate supervisor completes a Lockout Removal Report and Notification to Employee Report after it has been determined that it is safe to remove the lock and tag.
  4. The lockout device and information tag is removed with a witness present (preferably a member of the Joint Health and Safety Committee or a Safety Office representative), and secured by the appropriate supervisory personnel.
  5. A copy of the Notification to Employee must be given to the person who applied the lockout device and tag before the start of their next working shift.

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Appendix C

Group lockout

When a group of employees are working on a piece of equipment that has multiple energy isolation devices that require lockout use the following procedure:

  1. A UWaterloo supplied lock is placed on every isolation device in accordance with Appendix A.
  2. The lead hand (or group leader) verifies that every energy isolation device has been properly operated to isolate the energy source.
  3. The lead hand places the keys in a lock box.
  4. Each member of the group affixes their personal lock to the lock box.
  5. Work is performed.
  6. When work is complete and before the equipment is re-energized the Lead Hand will ensure that:
    1. Lockout devices have been removed and energy isolating devices have been returned to normal operating positions
    2. The equipment is operationally intact
    3. All necessary guards have been re-installed
    4. All tools used for the maintenance have been removed
    5. All maintenance personnel involved are clear and have been informed that the equipment is ready to be re-energized
  7. Equipment can be re-energized.

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