T.R. Consulting, Inc.

April 2003 Safety Article

Written and compiled by:

Tony Rieck

Copyright 2003 T.R. Consulting, Inc.




T.R. Consulting, Inc. regularly publishes safety and environmentally related articles on our website at http://www.trconsultinggroup.com/safety/archive.html. These articles are a free service provided by T.R. Consulting, Inc. to all interested parties in order to promote safety and environmental awareness.  T.R. Consulting, Inc. also provides safety training information and services.  Information about our safety training programs can be accessed at http://www.trconsultinggroup.com/safety/.


Note: T.R. Consulting, Inc. presents the information contained in this article as an aid in understanding of the subject matter.  Referenced standards must be read and thoroughly understood in order to assure compliance with the standard.  T.R. Consulting, Inc. attempts to provide accurate information, but makes no warranty with regard to either the completeness or accuracy of the information contained herein.




The lock out/tag out standard (29 CFR Part 1910.147) requires employers to implement a program to prevent the release of potentially hazardous energy during maintenance and service activities.  The intent of the lock out/tag out standard is to prevent injuries due to the unexpected energization or start up of machinery or equipment and injuries caused by the release of stored energy.





Lock out/tag out programs apply to all forms of potentially hazardous energy, not just electrical isolation.  The many forms of potentially hazardous energy include, but are not limited to, mechanical, hydraulic, pneumatic, chemical, thermal and electrical energy sources.




Employers must establish an energy control program consisting of: energy control procedures, employee training programs, and periodic inspections to ensure the continued effectiveness of the program.  The purpose of the energy control program is to ensure that before service or maintenance operations commence, machines and equipment that could unexpectedly start up, become energized or release stored energy are isolated from their energy source(s) and made safe to work on.




The employer is required to develop, document and use specific procedures to control potentially hazardous energy when employees service equipment or machinery.  Not only can the employer develop procedures that are specific to the needs of a particular workplace, it is expected.  Thus, the lock out/tag out standard is largely performance based.  The employer must meet the requirements of the standard, but is provided with a great deal of flexibility in the design of the individual components of the program. 




At least once annually, an authorized employee who is not involved in the energy control procedure must:


*        Identify deficiencies in the procedures or deviations from the proscribed procedures.  Deficiencies found in procedures require review and amendment of the procedures to ensure they are protective of employees.  Observation of deviations by employees implementing energy control procedures requires correction and a review of the employees training with regard to the procedure.

*        Review of individual responsibilities of authorized employees implementing lock out procedures.

*        Review of individual responsibilities of both authorized and affected employees for all energy control procedures where tag out is used.

*        Documentation of the time, date, process, employees observed and the name of the authorized employee providing the review for each periodic inspection.




Training takes three forms: initial training, additional training and retraining.




Employees are required to be trained to a level that assures that they understand the purpose and function of the energy control program, and to assure that they have the knowledge and skills required to implement the component procedures that are a part of the program.  Initial training requirements vary dependent upon the employees role within the program.


*        Authorized employees must be trained to recognize sources of hazardous energy, the types of hazardous energy that can be encountered in the workplace, and procedure to be implemented to achieve energy isolation and control.

*        Affected employees must be trained to understand the purpose and use of energy control procedures.

*        Other employees need to be made aware of the workplace lock out/tag out procedures and instructed not to restart or reenergize machines or equipment that is locked out or tagged out.




Employees must be trained to recognize the limitations of a tag out program.  Training topics must include:


*        Tags warn but cannot physically prevent restart or reenergization of equipment or machinery.

*        Tags are not to be removed without authorization or in any other way circumvented.

*        Tags need to be legible and understandable to all employees.  This may require the use of dual language tags and standardized graphic depictions.

*        Tags must be made from a material which will withstand environmental exposures and be attached using a sturdy, reliable means.

*        Both authorized and affected employees should be cautioned against developing a false sense of security regarding the protections afforded by a tag out program.

*        Tags must be attached in a manner that will prevent accidental or inadvertent detachment.




Employees are required to receive additional training whenever:


*        The employee is assigned to a different machine or equipment.

*        New equipment machines or procedures are introduced.

*        The energy control program is changed or amended.

*        There is any reason to believe that there are inadequacies in any employees skill, knowledge or implementation of the energy control program or that deviations from proscribed procedures are occurring or have occurred.





The employer is required to maintain a record of all training or retraining conducted as a part of the employer’s energy control program.  The record must include the names of employees receiving training, the topics of training and the date on which the training was provided.




Lock out is to be used whenever a device is capable of being locked out. (except as provided for under the “full employee protection” allowance).   If lock out is not possible, it is permissible to implement a tag out procedure.  All new machines or equipment placed in service on or after January 2, 1990 must be capable of accepting a lock out device.  Additionally, any equipment or machinery that has undergone major repairs, renovations or modification on or after January 2, 1990 is required to accept a lock out device.




The employer may opt to implement a tag out program in lieu of a lock out procedure if the following conditions are met.


*        Tags must be attached where the lock out device would otherwise be placed.

*        The employer must meet all of the tag out provisions and implement additional safety measures that can be demonstrated to provide no less protection than a lock out device.




The following requirements apply to lock out and tag out devices.  Lock out/tag out devices must be:


*        Durable

*        Easily identified

*        Standardized by color, shape or size

*        Tag out devices must be of a standard print and format

*        Not be used for other purposes

*        Only be applied where isolation can be achieved

*        Clearly identify the employee applying the device

*        Substantial enough to prevent removal without use of excessive force (i.e. bolt cutters, hack saws, etc.)

*        Not deteriorate due to any workplace exposures

*        Attached or locked by an acceptable means

*        Contain a legend (i.e. Do Not Operate, Do Not Start, etc.)

*        Contain a warning regarding the hazardous condition that it is meant to prevent




The following procedures must be performed in the following order for all lock out/tag out programs:


*        Prepare for shut down

*        Machine or equipment shut down

*        Isolation of the machine or equipment

*        Lock out/tag out device application

*        Stored energy relief, disconnection or restraint

*        Verification of isolation (attempted start)




Before lock out/tag out devices can be removed, the following procedures must be followed:


*        The machine or equipment must be inspected to ensure that operational components are intact and nonessential tools, spare parts, etc. have been removed.

*        The work area must be checked to assure that all employees have been notified and are cleared from any areas of potential exposure.

*        The lock out/tag out device is removed by the employee who applied the device.




The employer (on-site) and any outside contractors must inform each other of their energy control programs and responsibilities.  Both the outside contractor and the employer (on-site) are required to comply with the lock out/tag out standard and the employer (on-site) must ensure that his/her employees understand and comply with the outside contractor’s energy control program.




When a group of employees will be performing service or maintenance activities, the following additional requirements must be met:


*        The group lock out/tag out program must provide each individual employee with the same level of protection as is provided by the implementation of a personal lock out or tag out device.

*        A single authorized employee must be vested with the responsibility for the group of employees working under a group lock out/tag out program.

*        The single authorized employee must be aware of the status of each group member.

*        Each authorized employee must affix his/her own personal lock out/tag out device to the machine or equipment prior to the onset of work and remove it upon completion.




Employers must ensure that the energy control program provides continuity of employee protection when changes of shifts or personnel are possible during operations requiring lock out or tag out.  Orderly transfer of lock out/tag out device control is established through the implementation of procedures, training and rehearsals of program requirements.