This section provides an overview for lock-out and tag-out isolation
for a confined space in your workplace.

What Is a Lockout?

According to the Occupational Health and Safety Act, to lock out means “to physically neutralize all energies in a piece of equipment before [doing] any maintenance or repair work.” Although this may sound like a simple procedure, locking out equipment can become quite involved as there may be more than one source of energy, or locking out of several pieces of machinery might be necessary since quite often one piece of machinery might affect another. There may also be additional steps to take in order to protect workers from potential accidents. These will be discussed in detail throughout this course.

What Is Tagout?

It is a very similar procedure to lockout and is generally used when using padlocks are impractical. Once the equipment has been de-energized, a warning tag bearing the name and department of the person who has tagged out the equipment is placed on the energy-isolating device that has been turned to the off position. The tag must be of durable, weatherproof construction, made of non-conductive material and able to withstand corrosive environments. When tags are the only form of protection, additional training is required to inform all personnel of the associated hazards of removing a tag. In addition, the company must be able to prove that the tagout system is just as effective as a lockout system.

The Importance of Locking Out Equipment

Improper lockout procedures result in an astounding number of facilities and disabling injuries each year. This usually happens when a power source is inadvertently turned on while the machine is being worked on, resulting in a serious injury or death. Therefore, all lockout procedures must be followed strictly and thoroughly.

The following is a list of common accidents that occur when proper lockout procedures are not followed:

Electrocution

Working on any machinery is hazardous, especially since you may come in contact with wires that may become live if proper lockout procedures are not followed. Electrocution is one of the main causes of death. 

Cuts and Lacerations        

Many people receive deep cuts or lacerations when trying to escape from machinery that has been energized while they were inside it. Many of these injuries can become life-threatening due to infections that may develop. You must report and receive treatment for any injury, no matter how small, as it can become more serious.

Entanglement in Chains, Cogs, Conveyers and Rollers

One of the most common types of injury is being caught, entangled or pinched by moving machinery that has not been locked out properly, or that was accidentally re-energized. This type of injury usually results in the loss of fingers, hands, arms, feet or legs. Therefore, you must follow all lock out procedures carefully, and ensure that there will be no movement or tensing up of machinery parts.

Entrapment by Bulk Materials from Silos, Hoppers and Ladles

When working on industrial equipment, you must ensure that the area is clear and barricades are put in place so no materials can fall into the worksite, or block the entrance. Many people are killed each year because they were crushed by loose materials or suffocated because the exit point was blocked. In addition, make sure that all machinery that feeds into the equipment that you are working on is also locked out.

Drowning in Liquids Contained in Vats or Tanks    

Always check to ensure that the work area is dry and that all sources of liquid flow are blanked off to prevent any build-up of liquid. When working in a confined space, ensure that all emergency rescue procedures are in place. Drowning is a common cause of death when lockouts are not performed.

Burns

Due to contact with hot surfaces, burns are common when working on machinery. These burns can be avoided by allowing for adequate time for the equipment to cool to an acceptable level. Other causes are coming in contact with hot pipes and leaking valves containing heated materials. All pipes must be blocked off and bled before starting your work.

Fire and Explosions

If proper lockout procedures are not followed, fires and explosions are always a hazard. This may be caused by using flammable or combustible materials or by an oxygen-enriched atmosphere. Electrical arcs or sparks can easily ignite many materials and can lead to an explosion. This risk is increased when working in confined spaces.

Chemical Exposure

Exposure to chemicals in liquid or gaseous form may cause severe injury, illness and death. This is true when working around pipelines and storage tanks. Following the proper lockout and blanking procedures will reduce or eliminate these risks. These procedures include wearing the proper personal protective equipment (PPE) and becoming familiar with all chemicals that are present at the site.

Main Causes of Accidents

Virtually all of the accidents associated with performing service on machinery could have been avoided by following proper procedures and safety rules. Common sense also plays an integral role when identifying potentially dangerous situations and preventing accidents. Listed below are the main causes for lockout/tagout accidents:

• Working on equipment that is still running.
• Failing to disconnect the power source and de-energize the equipment.
• Not releasing built-up or residual energy.
• Accidental restarting of equipment by another worker.
• Restarting equipment without ensuring that the area is clear.

When Is a Lockout/Tagout Necessary?

Whenever there is a risk of accidental start-up of a machine, or the possibility of release of stored energy during servicing or maintenance operations, a lockout or tagout procedure must be performed. In addition, any time that a machine guard must be removed or bypassed, or where any part of your body can be pinched, trapped or caught by moving equipment, lockout or tagout procedures must also be performed.

You must realize that many minor service or maintenance projects also require that a lockout be performed. Some examples would include cleaning saws, changing light ballasts, un-jamming machinery, cleaning roller tracks and even some machinery inspections either require lockouts or tagouts.

There are two types of people involved in any lockout or tagout situation. Firstly, there are the people actually performing the work who are known as the Authorized personnel, and secondly, there are the people who operate the machinery, or work in the vicinity that the lockout/tagout will take place. These “bystanders” are known as Affected personnel.

Part of the responsibility of the authorized person is to notify all affected employees of the lockout/tagout, and the work that is to be performed, as well as any additional preventative measures that must be followed to avoid accidents.

Lockout/tagout Procedure

The following flowchart represents the steps that must be taken for locking or tagging out equipment. Upon receiving authorization to shut down equipment for maintenance, the first priority is to obtain a written checklist. This checklist will ensure that all policies and procedures are followed in the proper order, the correct Personal Protective Equipment and other precautions are taken and no steps have been missed.

Step I: Identify Energy Sources and Hazards

The first step is to prepare for shutdown is by identifying what types of energy will be involved (i.e., electric, hydraulic, pneumatic or pressure) as well as identifying other possible hazards such as chemical or temperature exposure. Be especially mindful of potential energies that have been built up or stored as this type of energy may have devastating results when released. Keep in mind that there may be more that one source and type of energy that powers a machine.

Step II: Shut Down the Equipment

The second step is to shut down the equipment using the normal stopping procedure for the equipment that is to be serviced. This may be as simple as turning off a switch or may involve following a shutdown procedure depending on the complexity of the machine. If this is the case, then you must follow the shutdown procedure accurately to prevent accidents.

Step III: Isolate and Disconnect Energy Sources

The third step involves carefully isolating the energy sources that feed the system. This is accomplished by throwing main disconnects and breakers, closing valves, disconnecting or capping any other energy sources such as hydraulic or pneumatic systems and pressure vessels. Always disconnect electrical power from the source; do not just rely on pulling fuses.

Step IV: Apply Locks, Tags and Other Warnings

The fourth step involves applying locks, tags, or other lockout devices (see next section) to all disconnect switches, valves, plugs and all other energy-isolating devices. Take the key with you. This will ensure that the equipment is not accidentally re-energized while the equipment is being serviced. Although locks are considered to be the best protection, tags should also be used in conjunction with the locks to provide important information regarding the lockout. Tags must display your name, department and notification that removal of a tag is strictly prohibited.

Step V: Relieve Potential Energy

The fifth step involves controlling any stored energy that may be present throughout the system. Potential energy is one of the most dangerous forms of energy because it can strike quickly and without warning; therefore, control of stored energy must be verified and monitored continuously until the work has been completed, or the hazard no longer exists.

The following are additional methods of controlling stored energy:

• Relieve, block or disconnect any energy that still may be present or that may feed the system.
• Make sure that all parts have stopped moving; learn to identify types of motion.
• Release any pressure in lines or pipes that may be trapped.
• Blank pipes.
• Discharge static or built-up electrical charges by attaching ground wires.
• Be sure to block and firmly support any elevated equipment.
• Block any machine parts that may collapse, fall or drift.
• Ensure that all spring-loaded parts are adequately blocked.

Step VI: Double Check the Lockout or Tagout

Always take the time to verify that the lockout procedure is complete before working on equipment. This simple double check will help to ensure your safety, as well as that of your co-workers.

• Notify all affected employees that the lockout is complete, and the work is beginning.
• Check to make sure that the lockout area is clear of personnel.
• Make sure that all locks and tags are firmly in place.
• Always test to make sure that the proper systems have been locked out.
• Test the equipment by pressing the start buttons, and then return them to the off position.
• Test electrical panels for live wires or circuits using an approved tester.
• Ensure that only authorized personnel will be working on the machinery.
• Make sure any required permits have been filled out in full, correctly and signed.
• Check the lockout status periodically to prevent accidental start-up of the equipment.

Various Lockout Devices

From time to time, you will encounter situations in which a padlock cannot be attached to the lockout site. Where this is the case, use one of the following lockout devices:

Ball Valve Lockout

After turning the valve handle to the off position, attach this device over the angled part of the valve handle as far as it will go, and ensure that the lower part of the device (paddle) is resting firmly against the pipe. Insert your padlock through the hole that has the tightest fit and check to make sure that the handle will not move.

Gate Valve Lockout

There are two methods for locking out gate valves. The recommended method is to use an approved gate valve lockout device; the other acceptable method is to lock the valve handle out by using chains. To attach a gate valve lockout, simply place the round device over the valve handle after the valve has been shut off and apply your lock and tag. Be sure to use the correct size of gate valve. 

Plug Locks

A plug lock is a device that surrounds a plug and clamps shut. After unplugging the equipment, select the proper size plug lock and clamp it shut around the plug. Now you can apply your lock and/or tag. A plug hugger is a device similar to a standard plug lockout device, only it has a locking mechanism built into it.

Wall Switch Lockout

To attach a wall switch lockout, you must first remove the wall switch plate screws and attach the base plate for the lockout device. Now turn the switch off and flip the lockout cover down to secure the switch in the off position and apply your lock.

Circuit Breaker Lockout

Turn the circuit breaker to the off position and attach the circuit breaker lockout device so that it is firmly in place and the breaker will not move. Now you may attach your lock and/or tag.

Fuse Lockout

Before pulling a fuse, always check by using an approved testing device to ensure that the circuit is not under an electrical load. Always use an approved fuse puller; do not use your hands or pliers to remove a fuse as this can result in serious injury or death. Now remove the fuse, apply the circuit breaker lockout device and attach your tag. Do not apply a lock as the metal-to-metal contact may cause a short circuit. Verify the de-energized state.

Group Lockouts

Quite often, more than one person is required to service the same equipment at the same time; this is called a group lockout. When this is the case, each person must take part in the lockout procedure by applying his or her own lock to a lockout bar or hasp at the energy-isolating device. This will prevent the equipment from accidentally being turned on before all work has been completed. Each authorized person must be trained in lockout procedures and be familiar with all company policies before starting the work.

We recommend a checklist be used in any lockout situation, as this will ensure that no steps are missed, and that all workers are informed of the potential hazards that may be present. In addition, the overall communication level between employees improves because all workers are following the exact same procedure.

Special lockout procedures are required for larger jobs that involve a group or crew of workers. When this is the case, a single competent person must supervise the entire procedure, and the procedure must remain under the control and authority of that person. Once locks are applied, all keys are deposited into a special lockbox that is under the control of the authorized supervisor of the project only. This procedure will enhance the safety aspect of group lockouts by ensuring that the appropriate locks are kept in place as the work is being completed.

Lockouts During Shift Changes

If the work is not completed at the time of a shift change, the lockout must remain in effect and you must remain at the lockout site until your replacement from the next shift arrives at the scene. This will give you the opportunity to inform the next shift workers of the lockout and of all work that has been completed thus far. Always take the time to take this crucial step before leaving the lockout site to provide for the safety of all concerned.

You must not remove your lock until your replacement has attached his. Remember to remove your lock before you leave. Please keep in mind that it is illegal to remove another worker’s lock! If you notice a lock belonging to another worker is attached and that worker has left for the day, notify your supervisor or management. Never cut a lock yourself, as there may be a reason that the lock has been kept in place.

Removing Locks and Tags

Once the equipment has been repaired or maintenance work has been completed, and the machinery is operationally sound, the following procedure must be performed:

• Remove all tools, parts and chemicals from the affected area.
• Inform all affected employees that the locks and tags will be removed shortly.
• Conduct a head count to ensure that the equipment and affected area is clear of personnel.
• Remove all locks, tags and warning devices. Remember, only you are authorized to remove your own lock, and it is illegal to remove a lock belonging to another worker.
• All tags should be signed. Tags and locks must be returned to the Safety Lock Control Board.
• Remember to sign your lock in on the register.
• Check to make sure that all machine guarding is securely in place.
• Follow all company procedures for restarting the equipment. Remember to use a checklist in order to avoid accidents. Always make sure that no one will be exposed to hazards during the start-up procedure.
• Observe the start-up procedure carefully to ensure that the equipment runs smoothly and that the work has been completed to the satisfaction of your company, and that the work complies with all company standards, as well as federal, provincial, state and municipal regulations.