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:
We'll cover each one of these steps throughout the rest of the module.
The first step in controlling energy is to identify equipment in your workplace that needs service or maintenance. To do that:
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:
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.
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.
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:
Check out this great reference from DE energize that covers how to de-energize various types of energy.
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.
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:
Safe practices for dissipating potential energy:
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 constitute 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).
Under traditional lockout, each authorized employee places his or her 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.
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 ensure lockout/tagout, group lockout may be performed.
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.
It's your last chance! Verification means purposely confirming that equipment is separated from its energy source; therefore it is "isolated." The authorized employee must verify that:
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.
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 lockout or tagout devices are removed and energy is restored, there are some procedures the authorized employee must follow:
There are some things an employer must do if a worker who didn't apply the lockout/tagout device actually removes the device. The person in charge must accomplish three actions listed below:
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. Lockout or tagout devices may be removed temporarily 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.
Below is the sequence of action that must occur in the temporary removal of the lockout/tagout devices:
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.
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.
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 his or her 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.
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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.