Scheduled maintenance - Thursday, July 12 at 5:00 PM EDT
We expect this update to take about an hour. Access to this website will be unavailable during this time.
Lockout is defined in the Canadian standard CSA Z460-20 "Control of Hazardous Energy - Lockout and Other Methods" as the "placement of a lockout device on an energy-isolating device in accordance with an established procedure." A lockout device is "a mechanical means of locking that uses an individually keyed lock to secure an energy-isolating device in a position that prevents energization of a machine, equipment, or a process."
Lockout is one way to control hazardous energy. See the OSH Answers Hazardous Energy Control Programs for a description of the types of hazardous energy, and required elements of a control program.
In practice, lockout is the isolation of energy from the system (a machine, equipment, or process) which physically locks the system in a safe mode. The energy-isolating device can be a manually operated disconnect switch, a circuit breaker, a line valve, or a block (Note: push buttons, selection switches and other circuit control switches are not considered energy-isolating devices). In most cases, these devices will have loops or tabs which can be locked to a stationary item in a safe position (de-energized position). The locking device (or lockout device) can be any device that has the ability to secure the energy-isolating device in a safe position. See the example of the lock and hasp combination in Figure 1 below.
Tag out is a labelling process that is always used when lockout is required. The process of tagging out a system involves attaching or using an information tag or indicator (usually a standardized label) that includes the following information:
Note: ONLY the authorized individual who placed the lock and tag onto the system is the one who is permitted to remove them. This procedure helps make sure the system cannot be started up without the authorized individual's knowledge.
De-energization is a process that is used to disconnect and isolate a system from a source of energy to prevent the release of that energy. By de-energizing the system, the risk that the system could inadvertently, accidentally, or unintentionally cause harm to a person through the release of hazardous energy is eliminated.
Safety devices such as barrier guards or guarding devices are installed on systems to maintain worker safety while these systems are being operated. When activities such as maintenance, repair, or set-up; or the removal of jams, clogs or misaligned feeds are performed, these safety devices may be removed if there are other controls in place to reduce or eliminate the hazards.
Having a lockout/tag out program and procedures for these scenarios will reduce the risk of injury due to the unintended or inadvertent release of hazardous energy.
The purpose of a lockout/tag out program is to control hazardous energy. A lockout program should:
An effective lockout/tag out program will help prevent:
Each party in the workplace has a responsibility in the lockout program. In general:
Management is responsible for:
Supervisors are responsible for:
Authorized individuals are responsible for:
Note: The Canadian standard CSA Z460-20, Control of Hazardous Energy - Lockout and Other Methods contains more information and many informative annexes about various risk assessment, lockout situations, and other control methods.
An organization will have one overall lockout program; however for each unique machine or equipment, there will be a detailed procedure or work instruction that describes the steps to control the hazardous energy.
The written lockout procedure should specify:
Procedures and work instructions identify how the lockout process is to be carried out and may include pictures or images of what is being described.
Lockout and tag out processes involve more than putting a lock on a switch. They are comprehensive step-by-step processes that involve communication, coordination, and training.
Please note the following definitions from CSA Z460-20:
Affected person - persons who are not directly involved in the work requiring the hazardous energy control, but who are (or may be) located in the work area.
Authorized person - a person who is qualified to engage in hazardous energy control because of knowledge, training, and experience and has been assigned to engage in such control.
General steps of a lockout/tag out procedure include:
1. Prepare for Shutdown
The authorized person will identify the machine, equipment, or process that requires lockout, which sources of energy are present and must be controlled, and what lockout device will be used. This step involves gathering all required equipment (e.g., lockout devices, tags, etc.).
2. Notify all Affected Personnel
The authorized person will communicate the following information to notify affected persons:
This information should also be present on the tag required for the lockout.
3. Equipment Shutdown
Follow shutdown procedures (either established by the manufacturer or employer). Equipment shutdown involves ensuring controls are in the off position, and verifying that all moving parts such as flywheels, gears, and spindles have come to a complete stop.
4. Isolation of System (De-energization)
Follow the lockout procedure for the identified machine, equipment, or process. Review the following isolation practices for various forms of hazardous energy:
For more types of energy, see Hazardous Energy Control Programs.
5. Dissipation (Removal) of Residual or Stored Energy
In general, examples include:
6. Lockout/Tag Out
When the system's energy sources are locked out, there are specific guidelines that must be followed to make sure that the lock cannot be removed, and the system cannot be inadvertently operated. These guidelines include:
7. Verify Isolation
Verify that the system is properly locked out before beginning any work. Verification can take place in several ways:
Choose the method that will make sure that the energy to the system has been isolated without creating other hazards during the verification.
8. Perform Maintenance or Service Activity
Complete the activity that required the system to be locked out.
9. Remove Lockout/Tag out devices
To remove locks and tags from a system that is now ready to be put back into service, the following general procedure can be used:
*Note: It is good practice to make sure any individual who placed a lock on the system should also be present when the system is re-started. This practice helps make sure those employees working on the system are not in a hazardous area when the machine is restarted.