August 2011- Lockout/Tagout




What is the purpose of OSHA’s Control of Hazardous Energy (Lockout/Tagout) standard?

Many workplace accidents are caused by machinery that accidentally becomes activated while being serviced or maintained. This accidental activation is called an "uncontrolled release of hazardous energy." Many of these accidents can be prevented if the energy sources are isolated, and locked or tagged out.

OSHA’s Control of Hazardous Energy (Lockout/Tagout) standard (29CFR 1910.147) helps safeguard employees from hazardous energy while they are performing service or maintenance on machines and equipment. The OSHA regulation requires that employer have documented clearance procedures to ensure that machinery does not start up while an employee is working on it.



What types of energy sources are potentially hazardous and require lockout/tagout?

Most people immediately think of electricity as a po­tentially hazardous energy source. There are other sources of energy, though, that can be just as hazardous. These energy sources include thermal, chemical, pneumatic, hydraulic, mechanical, and gravitational. It is important to remember that all sources of energy that have the poten­tial to unexpectedly startup, energize, or release must be identified and locked, blocked, or released before servicing or maintenance is performed.



What is Lockout/Tagout?

To keep equipment from being energized during repairs or maintenance, it can often be locked out. An energy isolating device (the disconnect switch or valve) is placed in the off position. A lock, either combination or key, is then placed over the energy isolating device. This lock remains over the energy source until servicing or maintenance is completed.

A piece of machinery is tagged out when the machine is turned off and a tag with a written warning is attached to the disconnect switch, circuit breaker or valve or other energy isolating device. The purpose of the tag is to assure that the equipment will not be operated until the tag has been removed. Tags used with the lock also identify the employee who is servicing the equipment.


When is Lockout/Tagout necessary?

Lockout/Tagout is required in general industry employment where servicing and maintenance of machines and equipment could cause injury to employees due to unexpected startup or release of stored energy. Such situations could occur when repairing electrical circuits, cleaning or oiling machinery with moving parts, or clearing jammed mechanisms.

Some examples of machine maintenance requiring lockout/tagout are listed below:

  • The employee must either remove or bypass machine guards or other safety devices, resulting in exposure to hazards at the "point of operation." (The point of operation is an area on a machine or piece of equipment where work is actually done upon the material being processed); 
  • The employee is required to place any part of his or her body in contact with the point of operation of the operational machine or piece of equipment. 
  • The employee is required to place any part of his or her body into an area on the machine where it could be caught by moving parts.



What does OSHA require?

OSHA requires employers to establish a lockout/tagout program that will:
  • Use energy control procedures, employee training and periodic inspection to ensure that machines or processes cannot be started while an employee is repairing, servicing or maintaining it. 
  • Ensure that new or overhauled equipment be designed to accept lockout devices; 

Lockout is often bypassed because it is difficult and takes too much time when there may be pressure to get a piece of equipment back on line. To avoid the temptation to bypass lockout procedures, lockout should be as easy and as fast as possible. OSHA requires that conveniently located lockout points must be designed and installed into machinery and equipment, whenever replacement or major repair, renovation or modification of a machine is performed.

  • Use a tagout program when locks cannot be used. The tagout program must provide employees with a level of safety equal to that obtained by using a lockout program; Note: tagout is not as effective as lockout, because tags can be bypassed. OSHA also allows tags to be used instead of locks in some cases 
  • Establish procedures for release of the lockout/tagout that includes machine inspection, notification and safe positioning of workers and removal of the lockout/tagout device; and 
  • Obtain locks, tags, chains, wedges, key blocks, adapter pins or self-locking fasteners that identify the employee using them. Locks and tags must be able to withstand the environment to which they are exposed for any extended period. For example, tags used outside should have a plastic covering. 



 What training does OSHA require for Lockout/Tagout?

As important as a lockout/tagout program is, it can only be effective if employees are aware of the program and trained properly.

Three types of employees are covered by the standard: authorized, affected, and other. The amount and type of training that employees receive depends on their job in relation to the machine that is being locked out or tagged out.

Authorized Employees: Employees who are authorized to execute the lockout/tagout and perform the servicing or maintenance should receive training in the:

  • recognition of all applicable hazardous energy sources (electrical, mechanical, hydraulic, pneumatic, chemical and thermal), 
  • details about the type and size of the hazardous energy sources present in the workplace, and 
  • methods necessary for controlling and isolating the energy source. 
 Authorized employees must possess the knowledge and skills necessary for the safe application, use and removal of energy controls.

Affected/Other Employees: Affected employees (usually the machine operators or users) and all other employees whose work operations may be in the area of the energy controls need to recognize when the control procedure is being set in motion. They also need to understand the purpose of the procedure and the importance of not using or starting up any equipment or machines that are locked out or tagged out.  

In other words, whenever a lockout or tagout device has been placed on a piece of machinery, the training must assure that all affected and other employees simply leave the equipment alone and not try to operate it.



Where can I find more information on OSHA’s Control of Hazardous Energy (Lockout/Tagout) standard?

To find more information refer to OSHA Safety and Health Topics: Control of Hazardous Energy (Lockout/Tagout)

Disclaimer: These Regulatory Reminders are not intended to be an exhaustive source for all of your particular facility’s compliance issues. They are designed to address the basics requirements with which most companies are required to comply. Following the Regulatory Reminder’s deadlines and Monthly Focus will not guarantee your compliance as these reminders are simply designed to help in your environmental/safety compliance efforts. You should always refer to the federal and your state’s regulations for all your requirements. Ultimately, your compliance with federal and state regulations is your responsibility. E&SSG assumes no liability for your compliance or the resources provided in these “Reminders”.


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