Lockout/Tagout: Control of hazardous energy
Lockout/tagout is the procedural step needed to shut down, isolate, block, and secure machines or equipment to a zero mechanical state. This process is necessary so employees can safely clean, lubricate, or repair machinery without the danger of an inadvertent start-up or release of stored energy. OSHA put this standard into effect on Jan. 2, 1990 to help safeguard employees from hazardous energy while they perform service or maintenance on machines or equipment.
This standard identifies procedures necessary to shut down and lock out equipment, requires that employees receive training in their role in the lockout/tagout program, and mandates periodic inspections to maintain or improve the energy control program.
LOCKOUT refers to installing a lock on an energy-isolating device (such as a circuit breaker, disconnecting switch, or shut-off valve) so the machine cannot be started until the lock is removed.
TAGOUT refers to tags or labels attached to the energy-isolating device to warn others not to restore energy to tagged equipment.
Lockout is OSHA's preferred device. Sometimes, the two methods are used together and, in some cases, tagout can be used instead of lockout. These procedures need to be coupled with employee training, annual inspection of procedures, and written documentation.
- Documented energy control procedures
- Employee training program
- Periodic inspection of procedures
The energy control written procedure must include:
- A statement of how the procedure will be used.
- The procedural steps to shut down, block, isolate, and secure machinery.
- Steps for the safe placement and removal of lockout devices and who has responsibility for them. On complex machines, the list of directions to properly de-energize the machine could be posted either on or by the machine.
- Specific requirements for testing the machine to determine the effectiveness of the control measures.
The procedures must include the following steps:
- Preparing for shutdown.
- Shutting down the machine.
- Isolating the energy sources from the machine.
- Applying the lockout or tagout devices.
- Safely releasing all potentially hazardous stored or residual energy.
- Verifying machine isolation before beginning maintenance work.
Steps to re-energize the machine
First, you should ensure that the machine's components are operationally intact. Next, notify affected employees that locked devices are removed by the employee who applied the device.
When a machine cannot be locked out, it must be tagged out. Tags are warning devices affixed to the energy-isolating devices and do not provide the physical restraint of a lock.
When a tag is applied, it should not be removed by anyone except the person who applied it. Tags must be legible and understandable to all employees. Tags also must be durable to withstand the environmental conditions of the workplace. If the energy-isolating device is lockable, it must be locked unless the employer can prove to OSHA that the use of tags is at least as effective as locks, ensuring full employee protection.
Requirements for lockout/tagout devices
- Locks and tags must be durable.
- They must be standardized according to size, color, or shape. Tags must be standardized according to print and format.
- They must be substantial enough to minimize early or accidental removal.
- They must be clearly identifiable.
The employer must provide employee training and verify that such training has been given to all covered employees. For the purpose of this standard, there are three types of employees: authorized, affected, and others.
Authorized employees are those applying the locks. They need to know the potential hazards of the machine, understand the procedures of lockout, and know methods of isolating energy sources.
Affected employees do not perform the maintenance, but need to understand the purpose of the lockout and not attempt to operate the equipment. Inspections of equipment and procedures should be performed at least annually. Every training program must ensure that all employees understand the purpose, function, and restrictions of the energy-control program, and that only authorized employees are to apply and remove the lockout devices.
Outside contractors working in the workplace need to be informed of the lockout procedures. Specific procedures must also be in place to ensure continuity of lockout during shift changes:
- All employees need to be made aware of lockout/tagout and recognize the locking device.
- Only authorized employees may apply the locking device.
- The employee who applied the lock should be the one to remove it.
- There should be only one key per lock to prevent unauthorized removal. The key should be in possession of the authorized employee who may be put in harm's way should the machine be activated.
OSHA estimates that compliance with this standard will prevent 122 fatalities, 28,400 lost work-day injuries, and 31,900 non-lost work-day injuries each year.
Classification of violations
- Deficiency capable of serious harm is cited as a serious violation.
- Failure to train authorized, affected, and other employees is cited as a serious violation.
- Paperwork deficiencies are cited as other-than-serious violations
For more information, reference 29CFR 1910.147 (Code of Federal Regulations) or contact your local OSHA office or State Bureau of Labor.