De-Energization & Lockout

Safe Work Processes

What is de-energization and lockout?

De-energization is the removal of hazardous energy from machinery or equipment before lockout is applied. De-energization may include shutting off a machine and unplugging it, or disconnecting a switch before a lock is applied to prevent the machine from being started up accidentally.

Once de-energization is complete, lockout can be applied.

Lockout is the use of lock(s) to render machinery or equipment inoperable or to isolate an energy source. The purpose of lockout is to prevent an energy-isolating device (e.g. circuit breaker, line valve) from accidentally or inadvertently being operated while workers are performing maintenance on machinery or equipment. Lockout makes sure machinery or equipment won’t start and injure a worker.

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When is de-energization and lockout required?

If machinery and equipment could unexpectedly activate or if the unexpected release of an energy source could cause injury, the energy source must be isolated and controlled through de-energization and lockout.

Examples of when de-energization and lockout may be required at UBC include installing, repairing, cleaning and lubricating machinery, equipment or systems.

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What is hazardous energy?

Hazardous energy is any energy source that could cause injury or death to workers. Types of hazardous energy include:

Electrical Energy is energy found in power lines, low-voltage and high-voltage equipment and is the most common form of energy used in workplaces
  • Electricity can harm workers by electrical shock, secondary injury or exposure to an electrical arc
Chemical Energy is energy released when a substance undergoes a chemical reaction
  • Hazardous chemical reaction may result in fire or explosion
Thermal Energy is energy from an explosion, flame, objects with high or low temperatures or radiation from heat sources
  • Release of thermal energy may cause burns, scales, dehydration or frostbite
Radiation Energy is energy from electromagnetic sources such as lasers, microwaves, infrared, ultraviolet, x-rays
  • Release of radiation energy may cause burns or changes to genetic material or reproductive systems
Kinetic Energy is the energy of moving equipment or materials
  • Equipment parts may move even after the electricity is turned off and some parts may need to be restrained or guarded so they can’t move and injure a worker

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What is potential energy?

Potential energy isstored energy often found in suspended, elevated or coiled materials. Types of potential energy include:

Hydraulic Potential Energy is the energy stored within a pressurized liquid
  • When under pressure, the liquid can be used to move heavy objects, machinery or equipment. The release of hydraulic energy may result in someone being crushed or struck by moving machinery, equipment or other items
Pneumatic Potential Energy is the energy stored within pressurized air
  • When under pressure, the air can be used to move heavy objects and power equipment. The release of pneumatic energy may result in someone being crushed or struck by moving machinery, equipment or other items
Gravitational Potential Energy is the energy related to the mass of an object and its distance from the ground. when gravity could cause something to fall or roll
  • When gravity could cause something to fall or roll

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How do I identify hazardous energy and assess the risk?

Before any work begins, a risk assessment should be conducted to identify hazardous energy related to the work performed. The following needs to be included:

  • Identify all tasks to be performed
  • Identify all potential sources of hazardous energy
  • Assess the risk level for each task and corresponding hazard
  • Determine how to de-energize each identified energy source
  • Identify each de-energized energy control device that must be locked out

Download UBC Risk Assessment template.
Download UBC Risk Assessment Guidance Document.

The information collected is then used to establish controls to eliminate or minimize the identified risks in the form of written lockout procedures.

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What is to be included in lockout safe work procedures?

Written lockout procedures must be developed for each machine, equipment or process and must include the following:

  • Identification of the machine, equipment or process
  • List of all required energy-isolation devices and their locations
  • Steps for shutting down, isolating, blocking, securing, and relieving stored or residual energy
  • Steps for placing and removing lockout devices
  • Requirements for verifying isolation and de-energization
  • Requirements for verifying that all workers have been cleared from the work site
  • Requirements for verifying that the machine, equipment or process has been inspected and is ready to return to service.

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Do I need de-energization and lockout training?

If work involves machinery and equipment that could unexpectedly activate or if the unexpected release of an energy source could cause injury, workers must receive instruction and training as per the Occupational Health and Safety Regulation and be knowledgeable in de-energization and lockout requirements, hazardous energy types, when locks are required, personal lockout, group lockout, and lockout procedures.

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How to obtain more information about de-energization and lockout?


See UBC De-Energization and Lockout Program (PDF)]

Additional Resources:

If you have any questions on De-Energization and Lockout at UBC, contact Safety & Risk Services



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