CONTROL OF HAZARDOUS ENERGY (LOCKOUT/TAGOUT)
Introduction Glossary
Scope and Application Normal Production Operations
Provisions of the Standard
References:
Discussion/Overheads - 1.94 MB
Student Handouts - 216 K
INTRODUCTION
This standard helps safeguard employees from hazardous energy while they are performing service or maintenance on machines and equipment. The standard identifies the practices and procedures necessary to shut down and lock out or tag out machines and equipment, requires that employees receive training in their role in the lockout/tagout program, and mandates that periodic inspections be conducted to maintain or enhance the energy control program.
In the early 1970's, OSHA adopted various lockout-related provisions of the then existing national consensus standards and Federal standards that were developed for specific types of equipment or industries. When the existing standards require lockout, the new rule supplements these existing standards(1) by requiring the development and utilization of written procedures, the training of employees, and periodic inspections of the use of the procedures. OSHA has determined that lockout is a more reliable means of de-energizing equipment than tagout and that it should always be the preferred method used by employees. The Agency believes that, except for limited situations, the use of lockout devices will provide a more secure and more effective means of protecting employees from the unexpected release of hazardous energy or start-up of machines and equipment. FOOTNOTE(1) The following OSHA standards currently contain lockout/tagout related requirements: 1910.178 - Power Industrial Trucks; 1910,179 - Overhead and Gantry Cranes; 1910.181 - Derricks; 1910.213 - Woodworking Machinery; 1910.217 - Mechanical Power Presses; 1910.218 - Forging Machines; 1910.252 - Welding, Cutting and Brazing; 1910.262 - Textiles; 1910.263 - Bakery Equipment; 1910.265 - Sawmills; 1910.272 - Grain Handling; and 1910.305 - Electrical.
This rule requires that, in general, before service or maintenance is performed on machinery or equipment, the machinery or equipment must be turned off and disconnected from the energy source, and the energy-isolating device must be either locked or tagged out. OSHA estimates that adherence to the requirements of this standard can eliminate nearly 2% of all workplace deaths in establishments affected by this rule and can have a significant impact on worker safety and health in the U.S.
GLOSSARY
Affected employee - An employee who performs the duties of his or her job in an area in which the energy control procedure is implemented and servicing or maintenance operations are performed. An affected employee does not perform servicing or maintenance on machines or equipment and, consequently, is not responsible for implementing the energy control procedure. An affected employee becomes an "authorized" employee whenever he or she performs servicing or maintenance functions on machines or equipment that must be locked or tagged.
Authorized employee - An employee who performs servicing or maintenance on machines and equipment. Lockout or tagout is used by these employees for their own protection.
Capable of being locked out - An energy-isolating device is considered capable of being locked out if it meets one of the following requirements:
Energized - Machines and equipment are energized when (1) they are connected to an energy source or (2) they contain residual or stored energy.
Energy-isolating device - Any mechanical device that physically prevents the transmission or release of energy. These include, but are not limited to, manually-operated electrical circuit breakers, disconnect switches, line valves, and blocks.
Energy source - Any source of electrical, mechanical, hydraulic, pneumatic, chemical, thermal, or other energy.
Energy control procedure - A written document that contains those items of information an authorized employee needs to know in order to safely control hazardous energy during servicing or maintenance of machines or equipment. (A more comprehensive explanation is given beginning on page 6.)
Energy control program - A program intended to prevent the unexpected energizing or the release of stored energy in machines or equipment on which servicing and maintenance is being performed by employees. The program consists of energy control procedure(s), an employee training program, and periodic inspections.
Lockout - The placement of a lockout device on an energy - isolating device, in accordance with an established procedure, ensuring that the energy - isolating device and the equipment being controlled cannot be operated until the lockout device is removed.
Lockout device - Any device that uses positive means such as a lock, either key or combination type, to hold an energy - isolating device in a safe position, thereby preventing the energizing of machinery or equipment. When properly installed, a blank flange or bolted slip blind are considered equivalent to lockout devices.
Tagout - The placement of a tagout device on an energy - isolating device, in accordance with an established procedure, to indicate that the energy - isolating device and the equipment being controlled may not be operated until the tagout device is removed.
Tagout device - Any prominent warning device, such as a tag and a means of attachment, that can be securely fastened to an energy - isolating device in accordance with an established procedure. The tag indicates that the machine or equipment to which it is attached is not to be operated until the tagout device is removed in accordance with the energy control procedure.
SCOPE AND APPLICATION
The lockout/tagout standard applies to general industry employment and covers the servicing and maintenance of machines and equipment in which the unexpected start-up or the release of stored energy could cause injury to employees. (If employees are performing service or maintenance tasks that do not expose them to the unexpected release of hazardous energy, the standard does not apply.)
The standard establishes minimum performance requirements for the control of hazardous energy.
The standard does not apply in the following situations:
NORMAL PRODUCTION OPERATIONS
OSHA recognizes that machines and equipment present many hazardous situations during normal production operations - i.e., whenever machines and equipment are used to perform their usual production function. These production hazards are covered by rules in other General Industry Standards, such as the requirements in Subpart O of Part 1910 for general machine guarding and guarding power transmission apparatus (1910.212 and 1910.219). In certain circumstances, however, some hazards encountered during normal production operations may be covered by the lockout/tagout rule. The following paragraphs illustrate some of these instances.
Servicing and/or Maintenance Operations
If a servicing activity - such as lubricating, cleaning, or unjamming the production equipment - takes place during production, the employee performing the servicing may be subjected to hazards that are not encountered as part of the production operation itself. Workers engaged in these operations are covered by lockout/tagout when any of the following conditions occurs:
In the above situations, the equipment must be de-energized and locks or tags must be applied to the energy-isolation devices.
In addition, when normal servicing tasks - such as setting equipment up, and/or making significant adjustments to machines - do not occur during normal production operations, employees performing such tasks are required to lock out or tag out if they can be injured by unexpected energization of the equipment.
OSHA also recognizes that some servicing operations must be performed with the power on. Making many types of fine adjustments, such as centering the belt on conveyors, is one example. Certain aspects of troubleshooting, such as identifying the source of the problem as well as checking to ensure that it has been corrected, is another. OSHA requires the employer to provide effective protection for employees performing such operations. Although, in these cases, a power-on condition is essential either to accomplish the particular type of servicing or to verify that it was performed properly, lockout or tagout procedures are required when servicing or maintenance occurs with the power off.
Minor Servicing Tasks
Employees performing minor tool changes and adjustments and/or other minor service activities during normal production operations that are routine, repetitive, and integral to the use of the production equipment are not covered by the lockout/tagout standard, provided the work is performed using alternative measures that give effective protection.
PROVISIONS OF THE STANDARD
Energy Control Program
The lockout/tagout rule requires that the employer establish an energy control program that includes (1) documented energy control procedures, (2) an employee training program, and (3) periodic inspections of the procedures. The standard requires employers to establish a program to ensure that machines and equipment are isolated and inoperative before any employee performs service or maintenance where the unexpected energization, start up, or release of stored energy could occur and cause injury.
The purpose of the energy control program is to ensure that, whenever the possibility of unexpected machine or equipment start-up exists or when the unexpected release of stored energy could occur and cause injury, the equipment is isolated from its energy source(s) and rendered inoperative prior to servicing or maintenance.
Employers have the flexibility to develop a program and procedures that meet the needs of their particular workplace and the particular types of machines and equipment being maintained or serviced.
Energy Control Procedure
This standard requires that energy control procedures be developed, documented, and used to control potentially hazardous energy sources whenever workers perform activities covered by the standard.
The written procedures must identify the information that authorized(2) employees must know in order to control hazardous energy during service or maintenance. If this information is the same for various machines or equipment or if other means of logical grouping exists, then a single energy control procedure may be sufficient. If there are other conditions - such as multiple energy sources, different connecting means, or a particular sequence that must be followed to shut down the machine or equipment - then the employer must develop separate energy control procedures to protect employees. FOOTNOTE(2) See section on "Employee Training."
The energy control procedure must outline the scope, purpose, authorization, rules and techniques that will be used to control hazardous energy sources as well as the means that will be used to enforce compliance. At a minimum, it includes, but is not limited to, the following elements:
The procedure must include the following steps: (1) preparing for shutdown, (2) shutting down the machine(s) or equipment, (3) isolating the machine or equipment from the energy source(s), (4) applying the lockout or tagout device(s) to the energy-isolating device(s), (5) safely releasing all potentially hazardous stored or residual energy, and (6) verifying the isolation of the machine(s) or equipment prior to the start of service or maintenance work.
In addition, before lockout or tagout devices are removed and energy is restored to the machines or equipment, certain steps must be taken to re-energize equipment after service is completed, including: (1) assuring that machines or equipment components are operationally intact; (2) notifying affected employees that lockout or tagout devices are removed from each energy-isolating device by the employee who applied the device. [See sections 6(e) and 6(f) of 29 CFR 1910.147 for specific requirements of the standard.]
Energy-Isolating Devices
The employer's primary tool for providing protection under the standard is the energy-isolating device, which is the mechanism that prevents the transmission or release of energy and to which all locks or tags are attached. (See glossary for a more complete definition.) This device guards against accidental machine or equipment start-up or the unexpected re-energization of equipment during servicing or maintenance. There are two types of energy-isolating devices: those capable of being locked and those that are not. The standard differentiates between the existence of these two conditions and the employer and employee responsibilities in each case.
If the energy-isolating device is lockable, the employer shall use locks unless he or she can prove that the use of tags would provide protection at least as effective as locks and would assure "full employee protection."
Full employee protection includes complying with all tagout related provisions plus implementing additional safety measures that can provide the level of safety equivalent to that obtained by using lockout. This might include removing and isolating a circuit element, blocking a controlling switch, opening an extra disconnecting device, or removing a valve handle to reduce the potential for any inadvertent energization.
Although OSHA acknowledges the existence of energy-isolating devices that cannot be locked out, the standard clearly states that whenever major replacement, repair, renovation or modification of machines or equipment is performed and whenever new machines or equipment are installed, the employer must ensure that the energy-isolating devices for such machines or equipment are lockable. Such modifications and/or new purchases are most effectively and efficiently made as part of the normal equipment replacement cycle. All newly purchased equipment must be lockable.
Requirements for Lockout/Tagout Devices
When attached to an energy-isolating device, both lockout and tagout devices are tools that the employer can use in accordance with the requirements of the standard to help protect employees from hazardous energy. The lockout device provides protection by holding the energy-isolating device in the safe position, thus preventing the machine or equipment from becoming energized. The tagout device does so by identifying the energy-isolating device as a source of potential danger; it indicates that the energy-isolating device and the equipment being controlled may not be operated until the tagout device is removed. Whichever devices are used, they must be singularly identified, must be the only devices used for controlling hazardous energy, and must meet the following requirements:
The device for attaching the tag also must have the general design and basic characteristics equivalent to a one-piece nylon cable tie that will withstand all environments and conditions.
Employee Training
For the purposes of the standard, there are three types of employees - authorized, affected, and other. The amount and kind of training that each employee receives is based upon (1) the relationship of that employee's job to the machine or equipment being locked or tagged out, and (2) the degree of knowledge relevant to hazardous energy that he or she must possess.
For example, the employer's training program for authorized employees (those who are charged with the responsibility for implementing the energy control procedures and performing the service and maintenance) must cover, at minimum, the following areas:
By contrast, affected employees (usually the machine operators or users) and all other employees need only be able to (1) recognize when the control procedure is being implemented, and (2) understand the purpose of the procedure and the importance of not attempting to start up or use the equipment that has been locked or tagged out.
Because an "affected" employee is not one who is performing the service of maintenance, that employee's responsibilities under the energy control program are simple: Whenever there is a lockout or tagout device in place on an energy-isolating device, the affected employee leaves it alone and does not attempt to operate the equipment.
Every training program must ensure that all employees understand the purpose, function and restrictions of the energy control program and that authorized employees possess the knowledge and skills necessary for the safe application, use, and removal of energy controls.
Training programs used for compliance with this standard, which is performance-oriented, should deal with the equipment, type(s) of energy, and hazard(s) specific to the workplace being covered.
Retraining must be provided, as required, whenever there is a change in job assignments, a change in machines, equipment or processes that present a new hazard, or a change in energy control procedures. Additional retraining must be conducted whenever a periodic inspection reveals, or whenever the employer has reason to believe, that there are deviations from or inadequacies in the employee's knowledge or use of the energy control procedure.
Periodic Inspections
Periodic inspections must be performed at least annually to assure that the energy control procedures (locks and tags) continue to be implemented properly and that the employees are familiar with their responsibilities under those procedures. In addition, the employer must certify that the periodic inspections have been performed. The certification must identify the machine or equipment on which the energy control procedure was used, the date of the inspection, the employees included in the inspection, and the name of the person performing the inspection. For lockout procedures, the periodic inspection must include a review, between the inspector and each authorized employee, of that employee's responsibilities under the energy control procedure being inspected. When a tagout procedure is inspected, a review on the limitation of tags, in addition to the above requirements, must also be included with each affected and authorized employee.
Application of Controls and Lockout/Tagout Devices
The established procedure of applying energy controls includes the specific elements and actions that must be implemented in sequence.(3) These are briefly identified as follows:
(2) Shut down the machine or equipment. (3) Apply the lockout or tagout device. (4) Render safe all stored or residual energy. (5) Verify the isolation and de-energization of the machine or equipment. FOOTNOTE(3) See 29 CFR 1910.147(d) for the detailed requirements and language of the OSHA standard.
Removal of Locks and Tags
Before lockout or tagout devices are removed and energy is restored to the machine or equipment, the authorized employee(s) must take the following actions or observe the following procedures:
(2) Check the area around the machine or equipment to ensure that all employees have been safely positioned or removed; (3) Notify affected employees immediately after removing locks or tags and before starting equipment or machines; and (4) Make sure that locks or tags are removed ONLY by those employees who attached them. (In the very few instances when this is not possible, the device may be removed under the direction of the employer, provided that he or she strictly adheres to the specific procedures outlined in the standard.)
Additional Safety Requirements
Special circumstances exist when (1) machines need to be tested or repositioned during servicing, (2) outside (contractor) personnel are at the worksite, (3) servicing or maintenance is performed by a group (rather than one specific person), and (4) shifts or personnel changes occur.
(2) Remove employees from the machines or equipment area. (3) Remove the lockout or tagout devices as specified in the standard. (4) Energize and proceed with testing or positioning. (5) De-energize all systems, isolate the machine or equipment from the energy source, and reapply lockout or tagout devices as specified.
Discussion/Overheads - 1.94 MB
Student Handouts -216 K
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