Lockout/Tagout Program: The Control of Hazardous Energy
This section has been reviewed and updated as needed: May 2014
The purpose of this procedure is to prevent injuries resulting from failure to use practices and procedures necessary for the control of hazardous energy. This procedure establishes the minimum requirements for the lockout/tagout of energy sources in accordance with The Control of Hazardous Energy (Lockout/Tagout) OSHA Standard, 29 CFR 1910.147. It will ensure that machines and equipment are isolated from all potentially hazardous energy sources and are locked out or tagged out before individuals perform any servicing or maintenance work. These actions, if properly designed and implemented, will prevent the unexpected energization, start-up, or release of stored energy and prevent injury to employees.
The control of hazardous energy is required during activities necessary to prepare or maintain a machine or piece of equipment. These servicing and/or maintenance activities may include constructing, installing, setting up, modifying, maintaining, lubricating, cleaning, un-jamming, making minor adjustments, and tool changes. Servicing and/or maintenance during normal machine or equipment operations are covered whenever employees perform the following actions:
- Remove or bypass machine guards, open enclosures or other safety devices;
- Place any part of their bodies in or near a machine’s moving parts; or
- Place any part of their bodies in a danger zone associated with machine operation.
Lockout/tagout (LOTO) Devices
The preferred method of isolation is lockout/tagout, using department issued locks and tags. The physical protection offered by the use of a lock, when supported by the information provided on a tag, provides the greatest assurance of employee protection from the release of hazardous energy. The use of LOTO devices to protect employees from hazardous energy must be implemented as part of a comprehensive energy control program. The designated devices must be used for controlling energy and not for other purposes. The following criteria pertain to lockout/tagout devices:
LOTO devices must be durable enough to withstand conditions in the workplace environment. Tagout devices must not deteriorate or become illegible, even when used in conjunction with corrosive components such as acid or alkali chemicals or in wet environments.
LOTO devices must be standardized according to color, shape, or size. Tagout devices also must be standardized according to print and format. Tags must be legible and understandable by all employees. Tags must warn against hazardous conditions if the machine is energized, and offer employees clear instruction such as: “Do Not Start,” “Do Not Open,” “Do Not Close,” “Do Not Energize,” or “Do Not Operate.”
LOTO devices must be substantial enough to minimize the likelihood of early or accidental removal. Other than using a key or combination to remove a lock, employees must be able to remove locks only by using excessive force with special tools, such as bolt cutters or other metal-cutting tools. Tagout devices must have the minimum unlocking strength of no less than 50 pounds.
LOTO devices shall be affixed to each energy-isolating means by authorized individuals. Tagout devices must be labeled to identify the specific employees who are authorized to apply and remove them. The label must contain the name, date and contact information for the person performing the lockout/tagout. As a result, authorized employees will be given greater assurance that other employees know of their involvement in the work activity and that only they will be allowed to remove the devices.
Tags [Image 1] are warning devices that do not provide the physical restraint on energy-isolating devices as offered by lockout devices. Constant vigilance is required to ensure that: 1) the tags are properly applied; 2) the tags remain affixed throughout the duration of the servicing or maintenance job; and 3) no employee violates the tag by re-energizing the machine or equipment, either intentionally or inadvertently, before the tag is removed. Tags must be labeled to identify the specific employees who are authorized to apply and remove them. The label must contain the name, date and contact information for the person performing the lockout/tagout.
Tagout alone is only permitted when an energy-isolating device is not capable of being locked. A supervisor must provide written approval of the use of tagout alone instead of the preferred lockout/tagout method. Lockout capability must be provided, if feasible, for equipment or machines purchased after January 2, 1990, and for older equipment which undergoes extensive replacement, repair, renovation, or modification.
To ensure that a tagout system provides full employee protection, at least one added safety measure must be used in addition to tagging the energy isolation device. This additional measure is designed to protect an employee from injury or death through the inadvertent activation of an energy isolating device associated with human error, inadvertent contact, the loss or detachment of a tag, or from any other limitation of tags. Any additional control measure must be integrated into equipment specific procedures through sound hazard-specific analyses on a case-by-case basis. Such additional safety measures might include the:
- Closure of a second in-line valve (e.g., double block and bleed);
- Removal of a valve handle to minimize the possibility that machines or equipment might be inadvertently energized or started;
- Removal of an additional isolating circuit element (e.g., fuse);
- Opening of an extra disconnecting device (e.g., disconnecting switch; circuit breaker);
- Opening and then racking out a circuit breaker;
- Grounding of an electrical circuit, if the grounding practice would protect the employee if the tagged isolating device were operated; or
- Locking, blocking, or barricading a controlling switch.
Document supervisor approval and any additional safety measure on the Tagout System Justification form found in Appendix A.
Lockout/tagout Procedural Requirements
Departments shall develop and document equipment specific lockout/tagout procedures. Procedures must contain enough detail for authorized employees to have a clear understanding of the energy control measures. Detailed procedures allow employees to follow the steps associated with a machine LOTO to effectively control all types and forms of hazardous energy. Development of equipment specific procedures will require preplanning to determine where and how energy sources can be disconnected to safely de-energize circuits and equipment that are to be worked on.
The energy control procedures must clearly and specifically 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, these procedures must also include the following elements:
- A specific statement of the intended use of the procedures;
- The specific procedural steps for shutting down, isolating, blocking and securing machines or equipment to control hazardous energy;
- The specific procedural steps for the placement, removal and transfer of lockout or tagout devices and the responsibility for them; and
- The specific requirements for testing a machine to determine and verify the effectiveness of LOTO devices and other control measures.
A separate procedure is not required for each machine or piece of equipment. Similar machines and/or equipment with the same or similar types of controls, and which can be rendered safe using the same sequential procedural steps, can be covered by a single procedure. The procedure must satisfactorily address the hazards and specify the measures for controlling the hazards. For example, a single energy control procedure may be used for a group of woodworking machines, as long as the procedure includes each machine within its scope and has sufficient specificity to allow employees to effectively isolate the hazardous energy sources and safely return each of the machines to service. To assist with the development of equipment specific procedures, fill out the Equipment Specific LOTO Procedure Development Form found in Appendix B. The completed development form can be used to create a pictorial procedure that can be placed near equipment in motor control centers (see air handler example in Appendix B).
Preparation for Lockout
LOTO shall be performed only by authorized employees who are performing the servicing or maintenance. Authorized employees shall be certain, as to which switch, valve, or other isolating devices apply to the equipment being locked out. Employees shall locate and identify all isolating devices. More than one energy source (electrical, mechanical, or others) may be involved. Authorized employees also must be certain that local on/off control of the equipment is achievable. Before lockout commences, employees shall clear any questionable identification of energy sources with their supervisors.
Notification of Employees
Affected employees shall be notified by the employer or authorized employee of the application and removal of energy control devices. Notification shall be given before the controls are applied, and after they are removed from the machine or equipment.
Machine or Equipment Shutdown
The machine or equipment shall be turned off or shut down using the procedures established for the machine or equipment. An orderly shutdown must be utilized to avoid any additional or increased hazards to employees as a result of equipment de-energization.
Machine or Equipment Isolation
All energy-isolating devices that control the energy to the machine or equipment shall be physically located. Operate the switch, valve, or other energy-isolating device so that each energy source (electrical, mechanical, hydraulic, etc.) is disconnected or isolated from the equipment. The use of push buttons, selector switches, and other control circuit type devices as energy isolating devices is prohibited. Stored energy such as capacitors, springs, elevator machine members, rotating flywheels, hydraulic systems and air, gas, steam or water pressure, etc. must also be dissipated or restrained by methods such as grounding, blocking, repositioning, bleeding down, etc. Compressed air, hydraulic or steam lines must be bled, drained, and cleaned out. The isolation valves must be locked out and tagged.
Power Circuit Versus Control Circuit[Image 2]
Only power circuit devices are approved as energy-isolating devices. The power circuit distributes power (electric energy) from the source (main disconnect) to the motor (connected load). The control circuit controls the distribution of power through the use of a motor controller (motor contactor), system interlock device, on/off switch, or start/stop push buttons. The use of a control circuit device as the primary means of hazardous energy control does not adequately protect employees. These devices are vulnerable to hazards such as component failure, program errors, magnetic field interference, electrical surges, and improper use or maintenance. Locking out control circuit devices will not prevent a motor from starting if voltage is present in the power circuit.
Tagout or Lockout/Tagout Device Application
Tagout devices shall be affixed to each energy-isolating means by authorized individuals and shall be affixed in such a manner as will clearly indicate that the operation or movement of the energy-isolating means from the “safe” or “off” position is prohibited. The tagout device shall be located as close as safely possible to the means, in a position that will be immediately obvious to anyone attempting to operate the device. Use of tagout only is allowed in rare circumstances with prior written approval from a supervisor.
Lockout devices shall be affixed to each energy-isolating means by authorized individuals and shall be affixed in a manner that will hold the energy in a “safe” or “off” position. Attach an approved tag containing the name, date and contact information for the person performing the lockout/tagout. Employees must not attempt to operate any switch, valve, or other energy isolating device when it is locked or tagged out. Each employee must apply his own personal Lockout/Tagout device on the energy isolating device. No one can apply another employee’s LOTO device.
Group LOTO applies to servicing or maintenance activities when more than one employee is engaged in the operation. When servicing and maintenance is performed by a crew, craft, department or other group, a procedure must be utilized that affords each employee a level of protection equivalent to that provided by the implementation of a personal lockout or tagout device [Image 3]. This shall be accomplished by:
- One authorized individual with knowledge of the equipment performs lockout/tagout on the equipment for the whole crew. It shall be the responsibility of that individual to carry out all steps of the lockout/tagout procedure and inform the crew when completed. This individual will attach his lockout/tagout device to a multi-lock accepting device.
- Then, each affected employee shall affix a personal lockout/tagout device to the multi-lock accepting device when they begin work, and shall remove those devices when they stop working on the machine or equipment being serviced or maintained. Each employee must verify that all required equipment has been locked out. Each employee must apply his own personal LOTO device.
- When all service or maintenance has been completed, the primary authorized individual shall remove his lockout/tagout device and the multi-lock accepting device after all other affected employees remove their locks. Only the employee who attached the LOTO device may remove the device unless the conditions outlined in the “Lockout/Tagout Removal When Individual is not available” section are met.
- If multiple pieces of equipment are being locked out, multiple lockout/tagout devices may be used to lockout the machine or equipment with the keys being placed in a lockout box or cabinet that allows the use of multiple locks to secure it. Each individual will then use his own lockout/tagout device to secure the box or cabinet. As each person no longer needs to maintain his lockout protection, that person will remove his lockout/tagout device from the box or cabinet.
Verification of Isolation
Prior to starting work on machines or equipment that has been locked out and tagged out, the authorized employee shall verify that isolation and de-energization of the machines or equipment has been accomplished. Employees need to verify that: the machines or equipment have been shutdown properly; all of the energy-isolating devices were identified, located, and operated appropriately; the lockout/tagout devices have been attached to the energy-isolating devices correctly; and the stored energy has been rendered safe.
A combination of visual inspections and physical tests are required for proper verification of isolation. Visual inspections verify that the correct devices have been locked out in the correct position. Use physical tests such as a deliberate attempt to start a machine for further verification and/or the use of a test instrument. After ensuring that no personnel are exposed, operate the push button or other normal operating controls to make certain the equipment will not operate.
The key to effective verification of isolation using physical tests lies in the ability to gain local control of the equipment. If local control cannot be obtained, additional steps must be taken. The paragraphs below provide various scenarios with the steps required to achieve effective verification of isolation.
Equipment with HOA (hand/off/auto) and On/Off Disconnect Combination[Image 4]
The ability to place a piece of equipment in “hand” allows an authorized employee to gain local control of the equipment. For automated or remotely controlled equipment, placing the equipment in “hand” interrupts the control circuit and prevents the equipment from reenergizing due to programming. To verify isolation with this combination, switch the HOA to “off” and the on/off disconnect to “off”. Lockout and tagout the disconnect and attempt to restart the equipment by switching the on/off switch to “hand”. Verification is successful if the equipment does not start.
Equipment With Local Start/Stop Switch and On/Off Disconnect Combination
In this scenario, the equipment has a local start/sop switch and an on/off disconnect. However, the equipment does not have a HOA and is not remotely controlled. The authorized employee can turn the equipment off by selecting “stop” on the start/stop switch and “off” on the disconnect. Lockout and tagout the power disconnect and attempt to restart the equipment by selecting “start”. Verification is successful if the equipment does not start.
Equipment With an On/Off Disconnect Only
This situation applies to equipment that does not have a HOA or local start/stop switch but has a nearby power disconnect. Switch the disconnect to “off”. If the equipment is observed to be de-energized, wait 10 seconds and reactivate the disconnect. If the equipment is reenergized, switch the disconnect to “off” and perform LOTO. The final step is to witness that the equipment is de-energized. These steps also work for remotely controlled equipment because the steps demonstrate that local control is achievable.
Alternate Verification Method
If the steps outlined above are not possible, then an alternate verification method is required for LOTO. Examples of situations were an alternate method is required include when the equipment selected for LOTO cannot or should not be reenergized due to mechanical or electrical faults, local control is not available, or if there is any doubt about whether the correct disconnect has been selected. Alternate verification methods should be determined on a case-by-case basis and may require multiple steps including voltage testing. These methods must be reviewed by EHS.
Voltage testing is required to verify that electrical equipment has been de-energized when working on or near de-energized electrical utilization systems. Testing may also be required for alternate verification methods. Until the absence of voltage is verified, opening an electrical panel for testing is considered working on or near exposed live parts. Therefore, voltage testing invokes the OSHA Electrical Standard 1910.333, Selection and Use of Work Practices, and the personal protective equipment (ppe) requirements of NFPA 70E, Standard for Electrical Safety in the Workplace. In addition, testing should only performed by authorized and qualified employees as defined by OSHA and NFPA. Follow the steps below to verify the absence of voltage to establish an electrically safe work condition prior to working on or near de-energized electrical utilization systems:
- After placing the disconnecting device in the open position, if possible, visually verify that all switch blades are fully open or that circuit breakers are in the fully disconnected position. Arc flash rating clothing must be worn when opening the electrical panel door or cover to perform this step.
- Obtain a test instrument that is adequately rated for the work environment (CAT III or CAT IV). The use of low voltage proximity or non-contact voltage detectors to verify the absence of voltage must be supplemented with a direct contact meter. Proximity or non-contact voltage detectors may provide false readings due to interferences that block the electric field. Interferences can occur if a cable is shielded or has a ground or neutral conductor inside or if the user is wearing voltage-rated gloves or standing on a fiberglass ladder.
- While wearing the required ppe, use the voltage tester to test a similar known source to verify that the tester is operating properly.
- Use the voltage tester to confirm that the equipment has zero voltage. A measurement must be made from each conductor to ground and between each conductor to each other conductor (phase-to-ground and phase-to-phase).
- Again, use the voltage tester to test a similar known source to verify that the tester is operating properly.
Release From Tagout or Lockout/Tagout
Before the energy control devices are removed and energy is restored to the machine or equipment, the following actions shall be completed by authorized individuals:
- Each LOTO device must be removed by the employee who applied the device.
- Inspect machine/equipment system components to ensure that:
- non-essential tools and materials have been removed; and
- machine or equipment components are operationally intact.
- Check the work area to ensure all employees have been safely positioned or removed.
- Inform affected employees that the lockout or tagout devices have been removed and that the machine or equipment will be reenergized.
- Safely start-up (re-energize) the equipment in accordance with established procedures.
Testing or Positioning of Machines, Equipment, or Components
When testing or positioning of a machine or equipment is necessary, a sequence of actions to be undertaken to maintain the integrity and continuity of employee protection. These prescribed steps must be implemented, in sequence, prior to re-energization:
- Clear machine or equipment of tools and materials;
- Remove employees from the hazardous areas around the machine or equipment;
- Remove the lockout or tagout devices;
- Energize the machine and employ effective employee protection while testing or positioning machinery; and
- If additional servicing or maintenance is required, turn off all systems, isolate the machine from the energy source, and reapply lockout or tagout devices as specified in this procedure.
Lockout/Tagout Removal When Individual Is Not Available
When the individual who applied the energy control device is not available to remove it, that device may be removed under the direction of a supervisor. Removal may not be based on convenience and may not be done simply because the employee is not available at the LOTO location, but is still at the workplace. The removal procedure shall include the following elements:
- Verification by a supervisor that the authorized individual who applied the device is not at the facility.
- The supervisor will make all reasonable efforts to contact the individual to inform him that his energy control device is to be removed.
- The supervisor will assure that the affected individual has the knowledge of his energy control device being removed before he resumes work at the facility.
- The supervisor shall document the LOTO removal (see form in Appendix C).
The steps above are necessary to ensure that the employee who is protected by the device is not exposed to energy hazards either at the time of its removal or after its removal.
Shift or Personnel Changes
In the case of shift or personnel changes, a transition period will be established so that individuals may exchange their assigned energy control devices. The orderly transfer of personal LOTO devices between off-going and on-coming employees must ensure that there is no gap in coverage. Individuals assuming control of tagout or lockout/tagout of equipment shall be fully briefed in the scope and strategy of the work by those who are being relieved.
If outside contractors service or maintain machinery, the on-site employer (UNC) and the contractor must inform each other of their respective lockout or tagout procedures. The outside (contractor) employer is permitted to use either: the host employer’s energy control procedure; its own procedures; or a combination of the two procedures, provided the resulting procedure meets the requirements of the LOTO standard. This provision is intended to ensure that both the UNC employer and outside personnel are aware that their interaction can be a possible source of injury to employees. The UNC employer and the contractor also must each ensure that its respective employees understand and comply with all requirements of the contractor’s energy control procedures. Document the coordination of LOTO procedures on the Contractor Notification Form in Appendix D.
If the outside employer has no documented energy control procedures, or if their procedure allows tagout in lieu of lockout/tagout, they shall ensure that their personnel understand and comply with the procedures established in this program.
Periodic inspections must be performed at least annually to verify that energy control procedures are properly applied. These periodic inspections will ensure that the employees involved are familiar with their responsibilities and that employees maintain proficiency in the energy control procedures that they implement. The inspections must contain at least two components: 1) an inspection of each energy control procedure, and 2) a review of each employee’s responsibilities under the energy control procedure being inspected. Each energy control procedure must be separately inspected to ensure that the energy control procedure is adequate and is being properly implemented by authorized employees in accordance with the LOTO standard.
At a minimum, these inspections must include a demonstration of the procedures and must be performed while the authorized employees perform servicing and/or maintenance activities on machines or equipment. The inspections may be accomplished through random audits, safety tours, or planned visual observations. The inspector, who must be an authorized employee other than the ones utilizing the energy control procedure being inspected, must observe the implementation of the energy control procedure for the servicing and/or maintenance activities being evaluated and talk with employees implementing the procedure to determine that all the requirements of the LOTO standard are understood and being followed by employees.
Additionally, employers must certify that the prescribed periodic inspections have been performed. The certification must specify: 1) the machine or equipment on which the energy control procedure was used; 2) the date of the inspection; 3) the names of the employees included in the inspection; and 4) the names of the persons who performed the inspection. Use the form in Appendix E to document certification.
In order to provide adequate information, LOTO training must address, at a minimum, the following three areas:
- The purpose and function of the energy control program;
- The elements of energy control procedures relevant to employee duties; and
- The pertinent requirements and prohibitions of the LOTO standard.
The training must be specific to the needs of authorized, affected, and other employees who work in the area where LOTO is used. The degree of knowledge required for these three employee groups diminishes from authorized employee to affected employee to other employees. If tagout devices are used, all employees in all three categories must receive training regarding the inherent limitations of tags.
The employer must provide initial training for new hires before they begin any servicing and maintenance activities. Retraining must be provided annually and if a periodic inspection reveals, or an employer has reason to believe, that there are deviations from the application of the energy control procedure or inadequacies in an employee’s knowledge of the energy control procedure. The scope and content of all the retraining must be based upon the severity of the problems encountered and must be directed toward the elimination of those problems. Additionally, retraining must be provided for all authorized and affected employees whenever there is a change in job assignment, energy control procedures or hazards.
**Training documents/rosters must be sent to the UNC-CH Department of Environment, Health, and Safety (CB# 1650) so that the individuals who have completed the LOTO Training will receive proper credit.
- Affected Employee
- An employee whose job requires him/her to operate or use a machine or equipment on which servicing or maintenance is being performed under Lockout/Tagout or Tagout, or whose job requires him/her to work in an area in which such servicing or maintenance is being performed. Affected or authorized employees may disable, shut down, or turn off machines or equipment. An affected employee becomes an authorized employee when that employee’s duties include performing servicing or maintenance covered under the standard.
- Authorized Employee
- A person who locks out or tags out machines or equipment in order to perform servicing or maintenance on that machine or equipment. Also, any employee who implements a lockout and/or tagout system procedural element on machines or equipment (for servicing and/or maintenance purposes) is considered an authorized employee. This includes employees who:
- perform energy source isolation
- implement lockout and/or tagout on machines or equipment
- dissipate potential (stored) energy
- verify energy isolation
- implement actions to release LOTO
- test or position machines or equipment
- Capable of Being Locked Out
- An energy isolating device is capable of being locked out if it has a hasp or other means of attachment to which, or through which, a lock can be affixed, or it has a locking mechanism built into it. Other energy isolating devices are capable of being locked out, if lockout can be achieved without the need to dismantle, rebuild, or replace the energy isolating device or permanently alter its energy control capability.
- Connected to an energy source or containing residual or stored energy. Conductors and parts of electric equipment that have been de-energized, but have not been locked and tagged out, must be treated as energized parts.
- Energy Isolating Device
- A mechanical device that physically prevents the transmission or release of energy, including but not limited to the following: A manually operated electrical circuit breaker; a disconnect switch; a manually operated switch by which the conductors of a circuit can be disconnected from all ungrounded supply conductors, and, in addition, no pole can be operated independently; a line valve; a block; and any similar device used to block or isolate energy. Push buttons, selector switches and other control circuit type devices are not energy isolating devices. Programmable logic controllers (PLCs) are not considered energy isolating devices for purposes of the LOTO standard. Safety functions, such as stopping or preventing hazardous energy (motion), can fail due to component failure, program errors, magnetic field interference, electrical surges, improper use or maintenance, etc.
- Energy Source
- Any source of electrical, mechanical, hydraulic, pneumatic, chemical, thermal, or other energy.
- Group Lockout/Tagout
- Group LOTO allows authorized individual employees to be protected from hazardous energy when they are part of a group performing covered servicing or maintenance. Group LOTO is the means by which each authorized employee performing the servicing and/or maintenance exercises his or her control over the associated hazardous energy by attaching his or her personal LOTO device onto a group LOTO mechanism. It consists of personal LOTO devices, group LOTO devices/mechanisms, and equipment LOTO devices.
- Hazardous Energy
- Any energy, including mechanical, pneumatic, hydraulic, electrical, chemical, nuclear, and thermal energies, that could cause injury to employees.
- 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 Box
- A box used to hold keys to multiple Lockout/Tagout devices. Following steps in this procedure, it can be used for convenience when several employees are isolating multiple pieces of equipment.
- Lockout Device
- A device that utilizes a positive means such as a lock to hold an energy isolating device in the safe position and prevent the energizing of a machine or equipment. Included are blank flanges and bolted slip blinds.
- Lockout/Tagout Device
- A device that consist of both a Lockout Device and a Tagout Device.
- Servicing and/or Maintenance
- Workplace activities such as constructing, installing, setting up, adjusting, inspecting, modifying, and maintaining and/or servicing machines or equipment. These activities include lubrication, cleaning or unjamming of machines or equipment and making adjustments or tool changes, where the employee may be exposed to the unexpected energization or startup of the equipment or release of hazardous energy.
- Setting Up
- Any work performed to prepare a machine or equipment to perform its normal production operation.
- 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
- A prominent warning device, such as a tag and a means of attachment, which can be securely fastened to 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.
- Appendix A: Tagout Justification Form
- Appendix B: Equipment Specific LOTO Procedure Development Form
- Appendix C: Absentee Lockout Tagout Removal Form
- Appendix D: Contractor Notification Form
- Appendix E: Periodic Inspection Form