Lockout is the preferred method of isolating machines or equipment from energy sources. Following this simple procedure for use in both lockout or tagout programs will help you develop a procedure which meets the requirements of the Lockout/Tagout standard. This procedure may be used when there are limited numbers or types of machines or equipment or there is a single power source. For more complex systems, a more comprehensive procedure will need to be developed, documented, and utilized.
This procedure establishes the minimum requirements for the lockout or tagout of energy isolating devices. It shall be used to ensure that the machine or equipment is isolated from all potentially hazardous energy, and locked out or tagged out before employees perform any servicing or maintenance activities where the unexpected energization, start-up or release of stored energy could cause injury (Type(s) and Magnitude(s) of Energy and Hazards).
Appropriate employees shall be instructed in the safety significance of the lockout (or tagout) procedure (List name(s)/job title(s) of employees authorized to lockout or tagout). Each new or transferred affected employee and other employees whose work operations are or may be in the area shall be instructed in the purpose and use of the lockout or tagout procedure (List name(s)/job title(s) of affected employees and how to notify).
Make a survey to locate and identify all isolating devices to be certain which switch(s), valve(s) or other energy isolating devices apply to the equipment to be locked or tagged out. More than one energy source (electrical, mechanical, or others) may be involved. (List type(s) and location(s) of energy isolating means).
1. Notify all affected employees that a lockout or tagout system is going to be utilized and the reason therefore. The authorized employee knows the type and magnitude of energy that the machine or equipment utilizes and understands the hazards.
2. If the machine or equipment is operating, shut it down by the normal stopping procedure (depress stop button, open toggle switch, etc.)
3. Operate the switch, valve, or other energy isolating device(s) so that the equipment is isolated from its energy source(s). Stored energy (such as that in springs, elevated machine members, rotating flywheels, hydraulic systems, and air, gas, steam, or water pressure, etc.) must be dissipated or restrained by methods such as repositioning, blocking, bleeding down, etc. (List type(s) of stored energy-methods to dissipate or restrain).
4. Lockout and/or tagout the energy isolating devices with assigned individual lock(s) or tag(s) (List method(s); i.e., locks, tags, additional safety measures, etc.)
5. After ensuring that no personnel are exposed, and as a check on having disconnected the energy sources, operate the push button or other normal operating controls to make certain the equipment will not operate (List type(s) of equipment checked to ensure disconnections).
Caution: Return operating control(s) to "neutral" or "off" position after the test.
6. The equipment is now locked out or tagged out.
1. After the servicing and/or maintenance is complete and equipment is ready for normal production operations, check the area around the machines or equipment to ensure that no one is exposed.
2. After all tools have been removed from the machine or equipment, guards have been reinstalled and employees are in the clear, remove all lockout or tagout devices. Operate the energy isolating devices to restore energy to the machine or equipment.
In the preceding steps, if more than one individual is required to lockout or tagout equipment, each shall place his/her own personal lockout device or tagout device on the energy isolating device(s). When an energy isolating device cannot accept multiple locks or tags, a multiple lockout or tagout device (hasp) may be used.
If lockout is used, a single lock may be used to lockout the machine or equipment with the key being placed in a lockout box or cabinet which allows the use of multiple locks to secure it. Each employee will then use his/her own lock to secure the box or cabinet. As each person no longer needs to maintain his or her lockout protection, that person will remove his/her lock from the box or cabinet (List name(s)/job title(s) of employees authorized for group lockout or tagout).
Energy-Isolating Devices
Your primary tool for providing protection is the energy-isolating device, which is the mechanism that prevents the transmission or release of energy and to which locks or tags are attached. This device guards against accidental startup or the unexpected reenergization in machines or equipment during servicing or maintenance. There are two types of energy-isolating devices: those capable of being locked and those that are not. OSHA differentiates between the existence of these two conditions and the use of tagout when either condition exists.
When the energy-isolating device cannot be locked out, you must use tagout or you can modify or replace the device to make it capable of being locked out. When using tagout, you will need to comply with all tagout-related requirements and, in addition to the normal training required for all employees, you must train your employees in the following limitations of tags:
§ Tags are essentially warning devices affixed to energy-isolating devices and do not provide the physical restraint of a lock.
§ When a tag is attached to an isolating means, it is not to be removed except by the person who applied it, and it is never to be bypassed, ignored, or otherwise defeated.
§ Tags must be legible and understandable by all employees.
§ Tags and their means of attachment must be made of materials that will withstand the environmental conditions encountered in the workplace.
§ Tags may evoke a false sense of security. They are only one part of an overall energy control program.
§ Tags must be securely attached to the energy-isolating devices so that they cannot be detached accidentally during use.
If the energy-isolating device is lockable, use locks unless you can demonstrate that the use of tags would provide protection at least as effective as locks to ensure 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 while tags are attached.
OSHA requires that whenever major replacement, repair, renovation, or modification of machines or equipment is performed and whenever new machines or equipment are installed, you 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 correctly attached to an energy-isolating device, both lockout and tagout devices help protect employees from hazardous energy. A lockout device provides protection by preventing the machine or equipment from becoming energized. A 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 while the tagout device is in place. 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:
§ Durable — Lockout and tagout devices must withstand the environment to which they are exposed for the maximum duration of the expected exposure. Tagout devices must be constructed and printed so that they do not deteriorate or become illegible, especially when used in corrosive (acid and alkali chemicals) or wet environments.
§ Standardized — Both lockout and tagout devices must be standardized within your company according to either color, shape, or size. Tagout devices must also be standardized according to print and format.
§ Substantial — Lockout and tagout devices must be substantial enough to minimize early or accidental removal. Locks must be substantial to prevent removal except by excessive force of special tools such as bolt cutters or other metal cutting tools. Tag means of attachment must be nonreusable, attachable by hand, self-locking, and nonreleasable, with a minimum unlocking strength of no less than 50 pounds. 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.
§ Identifiable — Locks and tags must clearly identify the employee who applies them. Tags also must warn against hazardous conditions if the machine or equipment is energized and must include a legend such as: DO NOT START, DO NOT OPEN, DO NOT CLOSE, DO NOT ENERGIZE, DO NOT OPERATE.
Employee Training
Employees affected by lockout/tagout procedures must have initial training and retraining as necessary, and you must certify the training has been given. Include each employee's name and dates of training on the certification.
The Lockout/Tagout standard specifies three types of employees who need to be trained — authorized, affected, and other. The amount and kind of training that each employee receives is based on the relationship of that employee's job to the machine or equipment being locked or tagged out, and the degree of knowledge relevant to hazardous energy that he or she must possess. For example, your training program for authorized employees (those who have the responsibility for implementing the energy control procedures and performing the servicing or maintenance) must cover, at a minimum, the following areas:
§ Recognition of applicable hazardous energy sources,
§ Details about the type and magnitude of the hazardous energy sources present in the workplace, and
§ Methods and means necessary to isolate and control those energy sources (i.e., the elements of the energy control procedures).
By contrast, affected employees (usually the machine operators or users) and all other employees need only be able to recognize when the control procedure is being used, and 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" or "other" employee is not performing the servicing or 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 or other employee must leave it alone and not attempt to energize or operate the equipment.
Every employee 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 for authorized employees should deal with the equipment, type(s) of energy, and hazard(s) specific to the workplace being covered.
Retraining must be provided 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. Conduct additional retraining whenever a periodic inspection reveals, or whenever you have reason to believe, that there are deviations from or inadequacies in the employee's knowledge or use of the energy control procedure.
Periodic Inspections
A periodic inspection of each procedure, when used at least once a year, must be performed at least annually to ensure that the energy control procedures continue to be implemented properly and that the employees are familiar with their responsibilities under those procedures. Design the periodic inspections to correct any deviations or inadequacies that are observed. An authorized employee other than the one(s) using the energy control procedure must perform the periodic inspections.
In addition, certify that the periodic inspections have been performed. The certification has to include:
§ Identify the machine or equipment on which the energy control procedure was used,
§ Date of the inspection,
§ Employees included in the inspection, and
§ Name of the person performing the inspection.
For a lockout procedure, 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.
Consultants Performing Lockout/Tagout Periodic Inspections
In an interpretative letter dated October 29, 1996 OSHA clarified what constitutes inspections conducted by authorized employees, including consultants.
"… [Y]ou inquired whether it is the intent of OSHA by stating that "an authorized employee" shall conduct periodic inspections in the Lockout/Tagout standard, to preclude consultants and other third parties from conducting required periodic inspections and audits of a company's energy control program. Pursuant to 1910.147(c)(6)(i)(A), a periodic inspection must be performed by an authorized employee.
For the purpose of complying with the intent of this standard, authorized employee means a qualified person whom the authority and responsibility to perform a specific lockout or tagout inspection has been given by the employer. A qualified person is a person who has been trained and has demonstrated proficiency, in compliance with 1910.147(c)(7), to perform servicing and maintenance on the machine or equipment to be inspected.
Therefore, please note that the function of conducting periodic inspections by consultants would meet the above criteria for the purpose of complying with the lockout/tagout standard requirement."
Applying Controls and Lockout/Tagout Devices
The established procedure of applying energy controls includes the specific elements and actions that must be implemented in sequence. These are briefly identified as:
2. Shut down the machine or equipment,
3. Disconnect the energy isolating device,
4. Apply the lockout or tagout device. Lockout/tagout programs should be based on the principle of only one key for each lock the worker controls. This means that:
§ Workers are assigned individual locks operable by only one key for use in securing energy control devices (breaker panels, control valves, manual override switches, etc.).
§ Each worker maintains custody of the key for each of his or her assigned locks. Use of master keys should be reserved for unusual circumstances when the worker is absent from the workplace. However, if master keys are necessary, keep them under supervisory control. List the proper procedures for using them in the written program for controlling hazardous energy.
§ Each lock is labeled with a durable tag or other means that identifies its owner.
§ When work is performed by more than one worker, each worker applies his or her own lock to the energy-securing device. Scissors-type hasps made of hardened steel are available to facilitate the use of more than one lock to secure an energy control device.
§ All de-energized circuits and systems are clearly labeled with durable tags.
§ The worker who installs a lock is the one who removes it after all work has been completed.
§ If work is not complete when the shift changes, workers arriving on shift apply their locks before departing workers remove their locks.
§ Because tags can be easily removed, they are not a substitute for locks. Workers are safest with a program that uses both locks and warning tags to prevent systems from being inadvertently reenergized.
5. Render safe all stored or residual energy. This may involve isolating or blocking the energy. To isolate or block energy, take the following steps:
§ Disconnect or shut down engines or motors that power mechanical systems.
§ Deenergize electrical circuits by disconnecting the power source from the circuit.
§ Block fluid flow (gas, liquid, or vapor) in hydraulic, pneumatic, or steam systems by using control valves or by capping or blanking the lines (lines can be blanked by inserting a solid plate between the flanges of a joint).
§ Block machine parts against motion that might result from gravity (falling).
Some forms of energy must also be dissipated after a system has been deenergized. System components such as electrical capacitors, hydraulic accumulators, or air reservoirs may retain sufficient energy to cause serious injury or death even though the component has been deenergized, isolated, or blocked from the system and locked out. Energy can be dissipated by taking the following steps:
§ Vent fluids from pressure vessels, tanks, or accumulators until internal pressure is at atmospheric levels. However, do not vent vessels or tanks containing toxic, flammable, or explosive substances directly to the atmosphere.
§ Discharge capacitors by grounding.
§ Release or block springs that are under tension or compression.
§ Dissipate inertial forces by allowing the system to come to a complete stop after the machine or equipment has been shut down and isolated from its energy sources.
6. Verify the isolation and deenergization of the machine or equipment. This verification should ensure that all energy sources (including stored energy) are controlled (that is, deenergized, isolated, blocked, and/or dissipated) before work begins. Appropriate testing equipment should be required as needed.
Removing 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:
1. Inspect the work area to ensure that non-essential items have been removed and that machine or equipment components are intact and capable of operating properly. To ensure that equipment will operate as expected when it is reenergized, you should require qualified persons to inspect completed installation, maintenance, service, or repair work. The inspection should verify that installation, repairs, and modifications were performed correctly and that the correct replacement parts were used. When equivalent or updated parts must be substituted for original parts, the system may need to be modified. Reenergized equipment should be closely monitored for several operating cycles to ensure that it is functioning correctly and safely.
2. Check the area around the machine or equipment to ensure that all employees have been safely positioned or removed.
3. 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; and
4. Notify affected employees after removing locks or tags and before starting equipment or machines.
Additional Safety Requirements
Special circumstances exist when machines need to be tested or repositioned during servicing, outside (contractor) personnel are at the worksite, servicing or maintenance is performed by a group (rather than one specific person), and shifts or personnel changes occur during servicing or maintenance.
Testing or positioning of machines — OSHA allows the temporary removal of locks or tags and the reenergization of the machine or equipment only when necessary under special conditions, such as when power is needed for the testing or positioning of machines, equipment, or components. The reenergization must be conducted as follows:
§ Clear the machines or equipment of tools and materials,
§ Remove employees from the machines or equipment area,
§ Remove the lockout or tagout devices as specified,
§ Energize and proceed with testing or positioning, and
§ Deenergize all systems, isolate the machine or equipment from the energy source, and reapply lockout or tagout devices as specified.
Outside personnel (contractors) — The onsite employer and the outside employer must inform each other of their respective lockout or tagout procedures. Each employer must ensure that his or her personnel understand and comply with all restrictions and/or prohibitions of the other employer's energy control program.
Group lockout or tagout — When servicing and/or maintenance is performed by a crew, craft, department or other group, they must 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.
Shift operations — During shift operations either maintain continuous control of the energy-isolating devices or require that the oncoming shift verify deenergization and lockout/tagout.
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