Course 621 Controlling Hazardous Energy (Lockout/Tagout)

Lockout/Tagout Procedures

To control hazardous energy, you must prevent it from being transmitted from its source to the equipment that it powers. You can accomplish that by doing the following:

  1. Identify energy sources and energy-isolating devices.
  2. De-energize equipment by isolating or blocking the energy sources.
  3. Secure energy-isolating devices in a safe position.
  4. Dissipate or restrain potential energy that can't be isolated.
  5. Verify equipment isolation.

We'll cover each one of these steps throughout the rest of the module.

1. To control hazardous energy, you must _____.

a. stop the energy from being transformed prior to maintenance
b. block unwanted currents from being grounded at the source
c. prevent it from being transmitted from its source to the equipment that it powers
d. make sure it is controlled or eliminated to acceptable levels prior to servicing

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Lockout/Tagout is not always so simple.

Step 1. Identifying Energy Sources and Energy-Isolating Devices

The first step in controlling energy is to identify equipment in your workplace that needs service or maintenance. To identify equipment that needs servicing or maintenance:

  1. determine the form of energy that powers the equipment, including potential energy that may remain when the energy source is disconnected; and
  2. 2. label the energy sources so that workers will know which energy source powers what equipment.

Before an authorized employee turns off a machine or equipment, he or she must have knowledge of the type and magnitude of the energy, the hazards of the energy to be controlled, and the method or means to control the energy.

Identify equipment that needs service or maintenance. Determine the types of energy (there may be more than one) that powers the equipment, including potential energy that may remain when the energy sources are disconnected.

Example 1: Industrial coffee bean roasters must be serviced to maintain optimum bean flavor and reduce fire risk. Depending on equipment options, some have rotating, heated drums; natural gas burners; cyclone chaff collectors; rotating cooling agitators; motorized trays; powered paddles; cooling blowers; and integrated carbon monoxide and heat exhaust systems. Once turned off, the electrical, mechanical (moving parts), chemical (natural gas), and thermal (heated parts) energies must be identified and controlled.

After identifying the energy sources, identify the devices that will effectively separate or block the energy from the equipment, preventing its activation or movement. Each energy source must be disconnected with an energy-isolating device (EID). Energy-isolating devices are mechanical devices that physically prevent the transmission or release of energy.

Energy-isolating devices can be:

  • disconnect switches (main)
  • line valves
  • manually operated electrical circuit breakers
  • bolted blank flanges
  • bolted slip blinds
  • safety blocks
  • any similar device used to block or isolate energy

Example 2: Replacing a saw blade on a table saw. These tools have a rotating blade powered by an electric motor. Once turned off, the mechanical energy from the rotating blade must be allowed to come to a complete stop and the electrical energy must be controlled.

2. Before an authorized employee turns off equipment, he or she must have knowledge of all of the following, EXCEPT _____.

a. the method or means to control the energy
b. the hazards of the energy to be controlled
c. type and magnitude of the energy
d. the name and address of the manufacturer

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Step 2. De-Energize Equipment

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Buttons and switches are NOT energy-isolating devices.

Turn off or shut down equipment following established procedures. Stop buttons and on/off switches are used to shut down equipment. However, it's important to know that turning off the equipment does not separate the equipment from its energy sources.

The method you use to de-energize equipment depends on the types of energy and the means to control it. After the equipment has been shut down, engage the equipment’s energy-isolating devices, physically separating the equipment from the energy. For compressed air, this could mean closing a specific manually operated valve. For an electric motor, this could mean opening a manually operated circuit breaker.

Buttons and switches

Push-buttons, selector switches, safety interlocks, control circuit type devices, and programmable logic controllers (PLCs) used in many modern machine applications are NOT energy-isolating devices. Control circuitry meeting appropriate performance levels can provide alternative safeguarding during minor servicing activities.

Safe practices for de-energizing equipment:

  • Disconnect equipment from energy sources.
  • Disconnect motors from the equipment.
  • Disconnect electrical circuits (including batteries).
  • Block the fluid flow in hydraulic, pneumatic, or steam systems with control valve, blinds, or both.
  • Block equipment parts or materials that could be moved by gravity.

Check out this great reference from DE energize that covers how to de-energize various types of energy.

3. Which of the following statements is TRUE when you press the stop button on a piece of equipment?

a. The electrical energy is physically grounded to earth.
b. It does not separate the equipment from its energy source.
c. It is safe to perform maintenance or servicing on the equipment.
d. The stop button acts as the energy-isolating device.

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Step 3. Secure Energy-Isolating Devices In a Safe Position

When equipment has been shut down, and then de-energized using an energy-isolating device, nothing will prevent the energy-isolating device from accidentally (or intentionally) being turned on, reopened, or reactivated until it is secured.

Locking out, also known as lockout (LO), is a procedure for physically securing energy-isolating devices in an off, closed, or neutral position. A lockout device – typically a lock with a unique key – secures the energy-isolating device in a safe position. When an energy-isolating device is secured by a lockout device, it physically prevents the energy-isolating device from being manipulated.

Tagging out, also known as tagout (TO), when performed correctly, is a procedure for securing a warning sign to an energy-isolating device when a lockout device cannot be used.

Key Criteria When Applying Lockout/Tagout Devices

  • • Authorized workers must attach lockout or tagout devices to each energy isolating device.
  • Lockout devices, where used, must be attached in a manner that will hold the energy isolating devices in a "safe" or "off" position.
  • Where tagout devices are used, it must be attached in a manner that will clearly indicate that the operation or movement of energy isolating devices from the "safe" or "off" position is prohibited.
  • If the tag can not be attached directly to the energy isolating device, the tag must be located as close as safely possible to the device, in a position that will be immediately obvious to anyone attempting to operate the device.
  • A tagout device must be securely fastened to the energy-isolating device and must state that the equipment being serviced can't be operated until it is removed.

4. When an energy-isolating device _____, it physically prevents the energy-isolating device from being manipulated.

a. is placed as close to the lockout device as possible
b. is secured by a lockout device
c. is placed in the safe or off position
d. is secured by a tagout device

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Step 4. Dissipate or Restrain Potential Energy That Can't Be Isolated

The potential energy here is "blocked out" to prevent it from falling.

Stored energy must be released or restrained after equipment has been de-energized.

If the energy could return to a hazardous level, make sure that it remains isolated from the equipment until all service work is finished. Sources of stored energy include:

  • capacitors;
  • coiled springs;
  • elevated machine parts;
  • rotating flywheels; and
  • air, gas, steam, chemical, and hydraulic systems.

Safe practices for dissipating potential energy:

  • Drain pressurized fluids or gases until internal pressure levels reach atmospheric levels.
  • Discharge capacitors by grounding them.
  • Double block and bleed process piping.
  • Release or block tensioned springs.
  • Ensure that all moving parts, such as flywheels and saw blades, have come to a complete stop.
  • Allow equipment components to cool (or warm) to safe thermal levels.

Just shutting off the air supply to an automatically operated air valve or turning off a hydraulic power unit without bleeding off the pressure does not make up energy isolation. Energy isolation is achieved when there is no energy left to be released. For this reason, many companies refer to their energy control program as zero energy state (ZES).

5. When has energy isolation effectively been achieved?

a. When there is no energy left to be released
b. When energy-isolation devices have been applied
c. When stop buttons and on-off switches have been cycled
d. When stored energy is reduced to acceptable levels

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Traditional Lockout vs. Group Lockout

Traditional Lockout

Group Lockout/Tagout with multiple energy-isolating devices. (OR-OSHA)

Under traditional lockout, each authorized employee places their personal lock on each energy-isolating device before beginning service work, and then removes that lock after the work has been done. Service work involving many employees and many energy-isolating devices can make traditional lockout complicated.

Group Lockout

In many workplaces, however, a group of authorized employees may need to service equipment that has several energy sources and several energy-isolating devices. To be most effective and ensure lockout/tagout, authorized employees may perform a group lockout/tagout.

Under the standard's group lockout/tagout requirements, a single authorized employee must assume the overall responsibility for the control of hazardous energy for all members of the group while the servicing or maintenance work is in progress. The authorized employee with the overall responsibility must implement the energy control procedures, communicate the purpose of the operation to the servicing and maintenance employees, coordinate the operation, and ensure that all procedural steps have been properly completed.

Example of the group lockout steps for a common process using a group lockbox.

  1. A designated, authorized employee in the group secures each energy-isolating device with a personal lock.
  2. The same designated, authorized employee places the key that fits each lock in a group lockbox with a multilock hasp.
  3. The other authorized employees in the group secure the lockbox – they attach their personal locks to the box – before beginning their service work.
  4. After each employee finishes service work on the equipment, that employee removes their personal lock from the lockbox.
  5. After all the employees have finished their service work and removed their personal locks from the lockbox, the designated, authorized employee who placed the key in the box removes it.
  6. The designated, authorized employee uses the key to remove the lock from each energy-isolating device.

6. When equipment servicing or maintenance must be performed by a group of authorized employees, what process may be used to most effectively perform lockout/tagout?

a. Groups are formed to do lockout/tagout on different parts of the equipment
b. Each authorized employee affixes locks/tags on all energy-isolating devices
c. The lead person attaches locks or tags so the others don't have to
d. Authorized employees use "group lockout" procedures using a lockbox

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Double block and bleed to isolate piping.

Step 5. Verify Equipment Isolation

It's your last chance! Verification means confirming that equipment is separated from its energy source; therefore it is "isolated." The authorized employee must verify that:

  • Equipment has been properly turned off/shut down.
  • Energy-isolating devices were identified and used to effectively isolate energy.
  • Individual lockout or tagout devices have been attached to the energy-isolating devices.
  • Stored energy has been removed or controlled.

Attempting to restart the equipment is one way to confirm isolation; however, testing equipment ensures that capacitors have been properly discharged, hazardous heat has dissipated, and excessive pressures have been relieved.

Best Practice: Some companies refer to their energy control program as "Lock, Tag, Try" or "Lock, Tag, Test" to emphasize this important verification step.

7. What is one common way to verify equipment has been successfully isolated?

a. Use your common sense knowledge
b. Listen for noise due to equipment operation
c. Try to restart the equipment
d. Verify lockout devices are installed

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Release from Lockout/Tagout

Return lockout/tagout devices to the lockout station to ensure they have all been removed from equipment.

OSHA's Lockout/Tagout standard includes requirements for releasing machines or equipment that have been locked out or tagged out prior to restoring energy to the equipment and using it.

Before removing lockout or tagout devices and restoring energy, the authorized employee must follow these procedures:

  1. The work area must first be inspected to ensure that nonessential items (e.g., tools, spare parts) have been removed and that all of the machine or equipment components are operationally intact.
  2. The work area must then be checked to ensure all workers have been safety positioned or have cleared the area. In addition, all affected workers must be notified that the lockout or tagout devices have been removed before the equipment is started.
  3. Each lockout or tagout device must be removed from the energy-isolating device by the employee who applied the device.
  4. To make sure all lockout/tagout devices have been removed, inventory them when you return them to the lockout station.

Alternative Steps for Release from Lockout/Tagout

There are some things an employer must do if a worker who did not apply the lockout/tagout device actually removes the device. The person in charge must accomplish three actions listed below:

  1. Verify that the authorized employee who applied the device is not at the facility.
  2. Make all reasonable efforts to contact the authorized employee to inform him/her that his/her lockout or tagout device has been removed.
  3. Ensure that the authorized employee knows that the lockout device has been removed before they resume work at the facility.

8. Before energy is restored during release from lockout/tagout, the authorized employee must do all of the following, EXCEPT _____.

a. inspect for non-essential items
b. check to ensure all workers are safely located
c. ensure each lockout/tagout device is properly removed
d. make efforts to contact safety staff to report the release

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Testing Machinery or Equipment

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Full release from and entry into lockout/tagout is required when testing.

In some circumstances, workers need to temporarily restore energy to a machine or piece of equipment during servicing or maintenance to test and /or reposition the machine or piece of equipment. Workers may temporarily remove lockout or tagout devices in order to perform these tasks. However, it is important to know that you may not use an abbreviated procedure during the release - test - restore sequence. You must use full lockout/tagout procedures anytime you release from lockout/tagout or restore equipment after testing and positioning.

Temporary Removal Procedures

Below is the sequence of action that must occur in the temporary removal of the lockout/tagout devices:

  1. The machine or equipment must be cleared of tools and materials.
  2. Workers must be removed from the machine or equipment area.
  3. All lockout or tagout devices may then be removed.
  4. Authorized workers may then proceed to energize and test or position the equipment or machinery.
  5. Following testing or positioning, all systems must be de-energized and energy control measures reapplied to continue the servicing and /or maintenance.

Release after Long-Term Shutdown

You should have an additional energy-control procedure to protect workers if they must restart equipment after long-term shutdowns. Determine who will be responsible for monitoring any lockout and tagout devices that control energy to the equipment. Include steps in the procedure for protecting workers if they need to remove or change parts while the equipment is shut down. Do not restart equipment until you are absolutely certain that it is working properly.

9. What lockout/tagout procedures may you use to temporarily test equipment to make sure your repairs have worked?

a. Full lockout/tagout procedures
b. Temporary lockout/tagout procedures
c. Abbreviated lockout/tagout procedures
d. Shortened lockout/tagout procedures

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The oncoming crew chief attaches locks first and then the offgoing crew chief removes locks.

Shift Change

How is the continuity of lockout or tagout protection maintained during shift or personnel changes?

Employers must ensure the continuity of employee protection by providing for the orderly transfer of lockout or tagout device protection between off-going and incoming employees. This will help to minimize exposure to hazards from the unexpected energization or start-up of the machine or equipment or the release of stored energy [29 CFR 1910.147(f)(4)].

Shift change procedure: If a lockout procedure will extend into the following shift, the employer will usually require the authorized employee who originally placed the lock to remove it. The ongoing authorized employee will then immediately replace the lock and continue the repair or maintenance on that equipment or machine for the following shift.

Working with Contractors

Whenever contractors and other outside servicing personnel perform tasks covered by the Lockout/Tagout standard, they must adhere to all the OSHA standard's requirements. The host employer and the contractor or outside employer must inform each other of the other's respective lockout or tagout procedures.

The host employer and the contractor must understand one another's lockout and tagout procedures. Make sure you review the contractor's energy-control program before the contractor does any on-site work. The host employer's workers must also understand and comply with the contractor's energy-control program.

Note: If you hire a one-person "independent contractor," he or she may claim they do not have to comply with State or Federal OSHA standards. They may be right, if they are not required to participate in a workers' compensation system. However, that does not relieve you, as the general or host employer, from legal liability under the OSHAct. Make sure you require all contractors, no matter what their business status is, to adhere, at a minimum, to OSHA standards. If the contractor puts up a fuss, I personally would not do business with the contractor.

If the sub-contractor is using their own LOTO procedures, the on-site general contractor or host employer must ensure that their workers understand and comply with the restrictions and prohibitions of the contractor or outside employer's energy control program.

Be sure to check out OSHA's 1910.147, Appendix A, Typical minimal lockout procedures for examples of lockout/tagout procedures.

10. What is the legal ramification if an independent subcontractor, who claims he or she does not have to comply with State or Federal OSHA regulations, performs servicing or maintenance tasks without using lockout/tagout procedures?

a. OSHA may not cite the host employer or the subcontractor
b. No legal problems: the subcontractor is covered by workers' compensation
c. The host employer is not relieved of legal liability under the OSHAct
d. Generally, the subcontractor may still be cited by OSHA, but it's rare

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If you have the time, watch this video by Dr. Roman Botstrum. He shows how the Lockout/Tagout process saves countless lives every year, and it only works when applied correctly. Dr. Botstrum walks you through the Lockout/Tagout procedure using his own invention, the JamStar 9000.

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