Firefighters may need to rescue people trapped in various forms of industrial machinery or elevators.


There are many types of potentially hazardous energy including, electrical, thermal, chemical, pneumatic, hydraulic, mechanical and gravitational energy. All such forms of energy must be locked out, blocked or released to ensure that machinery or equipment does not turn on or move while rescuing trapped people. Without adequate lockout, a sudden and uncontrolled release of energy from a system, machine or piece of equipment can occur, endangering firefighters.

Actions for employers

Employers should:

  • develop and implement safe lockout procedures
  • provide training in lockout procedures to those personnel who will perform rescue in any industrial machinery or energized electrical equipment

Using lockout to control energy sources

The term “lockout” refers to the methods, devices, and procedures for preventing the sudden and uncontrolled release of energy from a system, machine, or piece of equipment. Since energy is what a lockout system attempts to eliminate or control, it is important to identify all potentially active sources of energy associated with the piece of equipment involved.

Main energy sources provide power to a system, and include:

  • electricity
  • pneumatics
  • hydraulics

Stored or secondary energy stays in the system after the main source has been turned off, and includes:

  • electricity in batteries and capacitors
  • volatile chemicals in piping systems
  • pistons that move back and forth after the equipment’s power supply is turned off

Lockout considerations

Consider the following when performing lockout operations:

  • determine if there are personnel on site who possess a greater knowledge of the machinery, who can assist in locating shut-offs and in the disassembly of the machine
  • follow lockout instructions in the operator’s manual, if available
  • isolate the energy supply by locating power sources and ensure that lockouts are performed
    • for energized electrical equipment, locate the main line and disconnect and perform a lockout
    • for pneumatic/hydraulic equipment, locate line shut-offs and perform a lockout
    • for flowing liquid/solid applications, ensure that block-outs are performed and valves are closed
  • stored energy, such as that in capacitors, springs, elevated machine parts, rotating flywheels, hydraulic systems, and air, gas, steam, or water pressure, etc., should also be released, disconnected, or restrained by methods such as grounding, repositioning, blocking or bleeding-down
  • determine if lockout is required for any equipment that operates intermittently, such as a pump, blower, fan or compressor
  • if there is a possibility of re-accumulation of stored energy, such as an increase in pressure to a hazardous level, isolation of the equipment should be periodically verified until the rescue is completed, or until the possibility of such accumulation no longer exists
  • if a power supply is not physically locked out, assign personnel with radio communications to stand by the power source to make sure that the power supply is not turned back on

Applicable regulations and acts


  • Occupational Health and Safety Act
    • clause 25(2)(a) for providing information and instruction to a worker
    • clause 25(2)(d) for making workers aware of hazards
    • clause 25(2)(h) for taking every precaution reasonable in the circumstances to protect workers


For additional information about electrical safety, read Electrical Safety Handbook for Emergency Responders – Best practices for Coping with Electrical Hazards in Rescue and Fire Situations, Hydro One Networks Inc., Electrical Safety Authority, Office of the Fire Marshal, and Public Services Health and Safety Association, revised 5th Edition, 2013

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