De-Energization & Lockout

Safe Work Processes

What is De-Energization and Lockout?

Workers conducting repair and maintenance on equipment and machinery are exposed to possible serious injury should the equipment or machinery unexpectedly start-up or stored energy is released from the equipment or machinery.

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.

Lockout is the use of lock(s) to render machinery or equipment inoperable or to isolate an energy source. Once de-energization is complete, lockout can be applied. 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:

Type of Energy Example
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
Potential Energy is stored energy often found in suspended, elevated or coiled materials. Potential energy includes the following:
Type of Potential Energy Example
Mechanical Potential Energy is the energy stored in an item under tension
  • A spring that is compressed or coiled has stored energy that will be released in the form of movement when the spring expands. The release of mechanical energy may result in someone being crushed or struck by the object
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 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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When are Locks Not Required?

The application of a physical lock is not required if:

  • the energy isolating device is under the exclusive and immediate control of the worker at all times while working on the machinery or equipment, or
  • a tool, machine or piece of equipment which receives power through a readily disconnected supply, such as an electrical cord or quick release air or hydraulic line, is disconnected from its power supply and its connection point is kept under the immediate control of the worker at all times while work is being done
  • written safe work procedures are developed for this and workers are instructed and trained in those procedures

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    Can I Work on Energized Equipment for Maintenance Purposes?

    If it is not practicable to shut down machinery or equipment for maintenance, only the parts which are vital to the process may remain energized and the work must be performed by workers who:

    • are instructed, trained and qualified to do the work,
    • have been authorized by the employer to do the work, and
    • have been provided with and follow written safe work procedures

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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?

    WorkSafeBC has the following resource available:

    If you have any questions on De-Energization and Lockout at UBC, contact the Safety & Risk Services, Health, Safety and Environment Coordinator at 604-822-6732.

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