The Control of Hazardous Energy - Lockout/Tagout

Issued: June, 1994

Revised: Sept., 1996

Revised: February, 1999

Revised: July 2004

Office Location: Facilities Building - 37 Lee Street


.147 (a)(1) - Scope
This standard covers the servicing and maintenance of equipment and machines in which the unexpected energization or start up of machines or equipment, or release of stored energy could cause injury to employees.
.147 (a)(2) - Application
Standard Applies to:

  • This standard applies to the control of energy during servicing and/or maintenance of machines and equipment.
  • Servicing and/or maintenance which takes place during normal production operations is covered only if:
    • removal or bypass of a guard or other safety device is required
    • the employee is required to place any part of his or her body into the point of operations or other associated danger zone which exists during a machine operating cycle.
  • Standard does not apply to:
    • Work on cord and plug connected equipment for which the hazard of unexpected energization is controlled by unplugging the equipment from the energy source and where the plug is under the exclusive control of the employee performing the work.
    • Hot tap (welding on equipment under pressure) operations performed on pressurized pipelines involving transmission and distribution systems provided the employer demonstrates:
      • continuity of service is essential
      • system shut down is impractical
      • equipment is used to provide effective protection.
.147 (c) - General Requirements
.147 (c)(1) - The Energy Control Program
A program shall be established which consists of:

  • Energy control procedures
  • Employee training
  • Periodic inspections to ensure that before performing servicing or maintenance on a machine or equipment where unexpected energization could occur and cause injury, the machine or equipment shall be isolated from the energy source and rendered inoperative.
.147 (c)(2) - Lockout/Tagout
  • If an energy isolating device is not capable of being locked out, the employer shall, under their energy control program, utilize a tagout system.
  • If an energy isolating device is capable of being locked out, the employer shall, under their energy control program, utilize a lockout system, unless the employer can demonstrate that a tagout system will provide FULL employee protection as set forth in section(c)(3) of this standard (i.e., a level of safety equivalent to that obtained by using a lockout program).
  • Note:

    An "energy isolating device" is a mechanical device that physically prevents the transmission or release of energy (ex. manually operated electrical circuit breaker; a disconnect switch, etc.). This does not include push buttons, selector switches and other control circuit type devices.
  • Additional means to be considered as part of the demonstration of full employee protection shall include the implementation of additional safety measures such as:
    • Removal of an isolating circuit element
    • Blocking of a controlling switch
    • Opening an extra disconnecting device
    • Removal of a value handle to reduce the likelihood of inadvertent energization.
.147 (c)(4) - Energy Control Procedures
Procedures shall be developed, documented and utilized for the control of potentially hazardous energy and shall clearly and specifically outline the scope, purpose, authorization, rules and techniques to be used to achieve this control. They shall also outline the methods to ensure compliance.


This means the development of specific statements, procedural steps and requirements to ensure that the procedures set forth to control hazardous energy and prevent potential related injury are precisely followed.
.147 (c)(5) - Protective Materials and Hardware
  • Protective materials and hardware shall be provided by the employer.
  • Lockout and tagout devices shall be singularly identified and shall be the only device(s) used for controlling energy; these shall NOT be used for other purposes.
  • Lockout and tagout devices shall meet the following requirements:
    • They shall be durable - able to withstand the environment to which they will be exposed for the maximum expected exposure period.
    • The devices shall be standardized within the facility in at least one of the following criteria: color, shape, size, print and format.
    • Lockout devices shall be substantial enough to prevent easy removal. Tagout devices, including their means of attachment, shall be substantial enough to prevent inadvertent or accidental removal.
    • Lockout and tagout devices shall identify the employee applying the device. Tagout devices shall also have appropriate warnings regarding hazardous conditions.
.147 (c)(6) - Periodic Inspections
Inspections shall be conducted at least annually to ensure the Energy Control Procedures and the requirements of the "Lockout/Tagout" standard are being followed.

  • The inspection shall be performed by an authorized employee other than those using the procedure
  • Corrections shall be made to any identified inadequacies or deviations.
  • For lockout procedures, an oral review will take place between the inspector and the employee. This will cover the employees responsibilities as they pertain to the energy control procedures.

Documentation of these inspections shall include:

  • The identification of the machine or equipment the lock or tag was being used on.
  • The date of the inspection.
  • The name of the employee involved.
  • The name of the inspector.
.147 (c)(7) - Training and Communication
Training shall be provided and shall include:

  • Identification of hazardous energy sources in the work place covered by this standard, the type and magnitude of the energy available in the workplace and methods and means necessary for the isolation and control of the energy
  • The purpose and use of the Energy Control Procedures.
  • All other employees whose work operations are or may be in the area where energy controls may be used shall be instructed about the procedure and the prohibition of restarting or re-energizing locked or tagged out equipment or machines.
  • Specifically relating to tagout systems, training shall include information on the following tag limitations:
    • Tags do not provide the physical restraint provided by a lock.
    • Tags are not to be removed by other than the authorized employee and should never be bypassed, ignored, or otherwise defeated.
    • Tags must be legible and understandable by all.
    • Tags and the attachments must be able to withstand environmental conditions existing in the workplace.
    • It must be understood that tags are not physically restrictive and so may evoke a false sense of security.
    • Tags must be secured so they cannot be inadvertently or accidentally detached.


  • Shall occur whenever there is a change in job assignments, machines, equipment or processes that present a new hazard or when there is a change in the energy control procedures.
  • May also be conducted during the oral review of an inspection.


  • Documentation shall include the employees name and training dates.
.147 (c)(8) - Energy Isolation
Lockout or tagout shall only be performed by the authorized employees performing the servicing or maintenance.
.147 (c)(9) - Notification of Employees
Affected employees shall be notified of the application and removal of lockout or tagout devices. Notification shall occur before the controls are applied and after they are removed from the machine or equipment.


An "affected employee" is an employee whose job requires him/her to operate or use a machine or equipment on which servicing or maintenance is being performed under lockout or tagout, or whose job requires him/her to work in an area in which such servicing or maintenance is being performed.
.147 (d) - Application of Control - Lock or Tag
Procedures shall cover the following elements and shall occur in the following sequence:
.147 (d)(1) - Preparation for Shutdown
Before the employee turns off the machine or equipment, the authorized employee shall have knowledge of:

  • The type of energy to be controlled (i.e., electrical, mechanical, hydraulic, pneumatic, chemical, thermal, or other).
  • The hazards of the energy type.
  • The method or means to control the energy.
.147 (d)(2) - Shutdown
Shutdown shall occur using the procedures established for the machine or equipment and shall be done in an orderly way to avoid any additional or increased hazard(s) to employees as a result of the equipment stoppage.
.147 (d)(3) - Machine or Equipment Isolation
All energy isolating devices shall be located and operated in such a manner as to isolate the machine or equipment from the energy source(s).
.147 (d)(4) - Lockout/Tagout Device Application
  • Devices shall be affixed by authorized employees.
  • Lockout devices shall be affixed in a manner that will hold the energy isolating devices in a "safe" or "off" position.
  • Tagout devices shall be affixed in a manner to clearly indicate that the operation or movement of the energy isolating device from the "safe" or "off" position is prohibited.
  • Where tagout devices are used with energy isolating devices which are designed with the capability of being locked, the tag shall be fastened at the same point the lock would have been attached.
  • Where a tag cannot be affixed directly to the energy isolating device, the tag shall be located as close as safely possible to the device and will be immediately obvious to anyone attempting to operate the device.
.147 (d)(5) - Stored Energy
Following the application of lockout or tagout devices, all potentially hazardous stored or residual energy shall be relieved, disconnected, restrained and otherwise rendered safe. If there is a possibility of reaccumulation of stored energy, verification of isolation shall be continued until servicing or maintenance is completed, or until the possibility of such accumulation no longer exists.
.147 (d)(6) - Verification of Isolation
Prior to starting work on machines or equipment that have been locked out or tagged out, the authorized employee shall verify that isolation and de-energization of the machine or equipment have been accomplished.
.147 (e) - Release From Control - Lock or Tag
Before the lockout or tagout devices are removed, the authorized employee shall follow procedures and take action to ensure the following:
.147 (e)(1)
Inspect the work area to ensure that non-essential items have been removed and that machine or equipment components are operationally intact.
.147 (e)(2)
Ensure that all employees have been safely positioned or removed in the work area and that all affected employees are notified that the lockout or tagout device(s) have been removed.
.147 (e)(3)
Each lockout or tagout device shall be removed by the employee who applied the device. Any exception to this procedure must be documented in the employers energy control program and be in accordance with section (e)(3) of 1910.147.
.147 (f) - Additional Requirements
.147 (f)(1) - Testing or Positioning of Machines, Equipment, Etc.
In situations in which lockout or tagout devices must be temporarily removed to test or position the machine, equipment or components thereof, the following sequence of actions shall be followed:

  • Clear the machine or equipment of tools or materials
  • Remove employees from the machine or equipment area
  • Remove the lockout or tagout device(s)
  • Energize and proceed with testing or positioning
  • De-energize all systems and reapply energy control measures in accordance with this standard
.147 (f)(2) - Outside Personnel (Contractors)
Whenever outside service personnel are to be performing activities covered by this standard, the on-site employer and the outside employer shall inform each other of their respective lockout/tagout procedures. The outside employer shall ensure that his/her employees understand and comply with the restrictions and prohibitions of the on-site employers program. It is the responsibility of the outside employer to notify the on-site project manager of all activities covered by this standard prior to commencing such activities. Failure to comply with this standard will be regarded as a violation of contract.
.147 (f)(3) - Group Lockout or Tagout
When servicing and/or maintenance is performed by a group, they shall utilize a procedure which affords the employees a level of protection equivalent to that provided by the implementation of a personal lockout or tagout device.

There shall be an authorized employee with primary responsibility for a set number of employees working under the protection of a group lockout or tagout device.

When more than one crew or group is involved, an authorized employee shall be designated to coordinate the work forces and ensure continuous protection.

Each authorized employee in the group shall affix a personal lockout or tagout device to the group lockout device when he/she begins work, and shall remove those devices when he/she stops working on the machine or equipment being serviced.
.147 (f)(4) - Shift or Personnel Changes
Specific procedures shall be utilized during shift or personnel changes to ensure the continuity of protection, including a provision for the orderly transfer of lockout or tagout device protection between off-going and oncoming employees.