Lockout Tagout Policy

Document Number:
Published Date:
Revision #:

General Information


To prevent injuries and fatalities from unexpected and/or accidental release of energy or start up of machines or equipment, or release of stored energy during service, repair, maintenance, operation, and associated activities; and to outline general procedures for the safe lockout and tagout of electrical equipment, machinery and pressure systems.
This policy does not apply to the following:
(1) Work on cord and plug connected electric equipment for which exposure to the hazards of unexpected energizing or start up of the equipment is controlled by the unplugging of the equipment from the energy source and by the plug being under the exclusive control of the employee performing maintenance or repair.
(2) Hot tap operations involving transmission and distribution systems when they are performed on pressurized pipelines, provided that it has been demonstrated that:
a) continuity of service is essential;
b)shutdown of the system is impractical;
c) documented procedures are followed, and
d) special equipment is used which will provide proven effective protection for employees.


Health & Safety Co-Chairs

Terms and Definitions:



Affected employee
An employee who operates or uses a machine or equipment on which employee lockout/tagout systems are installed, or who works in areas affected by lockout/tagout procedures.

Authorized employee
A person who locks out and tags out machines or equipment to perform servicing or maintenance. An authorized employee is also someone who has received lockout/tagout training.

Energy source
Any source of electrical, mechanical, hydraulic, pneumatic, chemical, thermal, gravitational, stored or other energy.

Hot Tap
A procedure used in repair and maintenance activities which involves welding on a piece of equipment (pipelines, vessels or tanks) under pressure, in order 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 and steam distribution systems. Other methods of attachment can also be used.

A process to ensure that a machine is removed from service and completely protected from inadvertent start-up via any power source. A mechanical device is used (a disconnect switch, line valve, block, blank off plate) that physically prevents the transmission or release of an energy source to machinery or equipment.

To physically neutralize all energy sources in machinery or equipment, usually by applying locks, before beginning any maintenance or repair work. The primary purpose of lockout is to prevent all energy isolation devices (switch, circuit breaker or valve) from accidentally or inadvertently being operated while workers are working on equipment.

Lockout Device
A device that uses a positive means (such as a lock) to hold an energy isolation device (see “Isolation”) in a safe position and prevent the energizing of a machine or a piece of equipment. Each lockout device must always be accompanied by a tagout device. All lockout devices, must:
- be unique, distinctive, easily recognizable, and clearly visible
- be the only devices used for controlling potentially hazardous energy
- not be used for any other purpose
- be capable of withstanding the environment to which they are exposed
- be substantial enough to prevent operation of the energy isolating device without
the use of excessive force

Locks, by themselves, do not de-energize equipment. They are attached only after the machinery has been isolated from its energy sources.

Maintenance and repair
Workplace activities such as constructing, installing, setting up, adjusting, inspecting, modifying, and maintaining machines or equipment. These activities include but are not limited to lubrication, cleaning or un-jamming of machines or equipment and making adjustments or tool changes, where the employee may be exposed to the unexpected start-up of the equipment or release of hazardous energy.

Tagout device
A tag or sign, which must be attached to the lockout device, which is used to communicate vital information about the lockout, including the identity of the authorized employee who applied the device, the reason for locking out, and the date and time. It also warns workers not to operate that equipment. The tag must be substantial enough to withstand the environment, be secured to prevent inadvertent or accidental removal, and it must remain legible for the duration of the job. It must be made of non-conducting material and be placed in a conspicuous location.

Zero energy state
The mechanical potential energy in all elements of a machine is dissipated so that operation of any control will not produce a movement that could cause injury.


Responsible Department or Functional Area:

Joint Health & Safety Committee


Campus Operations
Information Technology
Joint Health & Safety Committee


Ontario Ministry of Labour Engineering Data Sheet 9-02: Lock-Out Procedure for Machinery

Ontario Regulation 851, R.R.O. 1990, Industrial Establishments, Sections 42,43,75,76

Occupational Health & Safety Act
Policy Provisions
  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10


    Written lockout/tagout procedures specific to a particular machine or equipment, or to a similar grouping of machines or equipment, must outline the situations in which they are to be used, and the sequence in which they are to be used. Lockout/tagout procedures shall clearly define the specific actions and responsibilities required during each of the following energy control sequences:
    1. Preparation for shutdown
    2. Equipment shutdown
    3. Equipment isolation from the energy source

    4. Application of lockout/tagout devices
    5. Release of stored energy, de-energization
    6. Verification of isolation
    7. Release from lockout/tagout control once work is completed, including removal of lockout/tagout devices and restoration of energy to machinery/equipment.

    Scope and Exceptions:

    It is not necessary to document the required procedure for a particular machine or equipment, when ALL of the following elements exist:
    1. The machine or equipment has no potential for stored or residual energy or re- accumulation of stored energy after shut down which could endanger employees;
    2. The machine or equipment has a single energy source which will completely de-energize and deactivate the machine or equipment and can be readily identified and isolated by a single lockout device;
    3. The machine or equipment is isolated from that energy source, locked out during servicing or maintenance and the lockout device is under the exclusive control of the authorized employee performing the servicing or maintenance;
    4. The servicing or maintenance does not create hazards for other employees;
    5. Utilizing this exception, has had no accidents involving the unexpected activation or start-up of the machine or equipment during maintenance or repair activities.
Related Documents

Primary Author / Owner:



Health & Safety Co-Chairs
[email protected]