Many serious accidents have happened when someone thought a machine or the power to it was safely off. “Lock-out tag-out” (LOTO) is a way to protect yourself and others by ensuring that machines remain completely, temporarily off. Without a lock-out tag-out system there is the possibility that a machine will unexpectedly start up, either because of stored energy that was not correctly released or through the actions of someone starting the process without realizing that it isn’t safe to do so. The UCSC LOTO program details the Cal/OSHA requirements, outlines responsibilities, and provides methods and forms for divisions to achieve and maintain compliance.
The lock-out tag-out standard requires that hazardous energy sources be “isolated and rendered inoperative” before maintenance or servicing work can begin. These energy sources include electrical (either active current or stored as in a capacitor), pneumatic, hydraulic, mechanical, thermal, chemical, and the force of gravity. It is important to remember all of the energy sources must be “isolated and rendered inoperative.” Overlooking an energy source has proved fatal on several occasions.
OSHA requires three basic elements in a lock-out tag-out program. These are training, written procedures, and inspections. Training is required for two types of people; “authorized employees” and “affected employees.” Authorized employees are people who do the maintenance or servicing work. They are the people who actually perform the lock-out tag-out. Affected employees operate or work in an area where servicing or maintenance is being performed on locked or tagged equipment. They are not authorized to perform the LOTO, but their work is impacted by the procedure, making it crucial for them to understand that the equipment is out of service and must not be re-energized.
Written lock-out tag-out procedures detailing the lock-out tag-out procedure are required under any of the following conditions:
- The equipment contains hazardous stored energy,
- The equipment has two or more energy sources,
- The energy-isolating device is not under the exclusive control of the employee, or
- The work creates new hazards.
Written procedures communicate important information to persons performing lock-out tag-out. They identify energy sources and their magnitude, the point of isolation, and the devices required for lockout. They also provide step-by-step instruction for locking or tagging out energy sources, releasing stored energy, and verifying the equipment cannot be re-started after lockout is applied. Group lock-out tag-out procedures must also be clearly documented. Procedures must be kept up-to-date with annual reviews, and changes must be communicated to everyone who may possibly be affected by them. They are only useful if all the information they contain is correct.
Six Basic Steps for Lock-out Tag-out
Think, plan, and check.
- If you are in charge, think through the entire procedure.
- Identify all parts of any systems that need to be shut down.
- Determine what switches, equipment, and people will be involved.
- Carefully plan how restarting will take place.
Communicate.
- Notify all those who need to know that a lock-out tag-out procedure is taking place.
- Identify all appropriate power sources, whether near or far from the job site.
- Include all hazardous energy sources, such as electrical circuits, hydraulic and pneumatic systems, spring energy, and gravity systems.
Shut down energy sources.
- Disconnect electricity.
- Turn off gas cylinder valves.
- Block movable parts.
Apply LOTO devices.
- Use Locks and tags on all energy isolating devices to secure the equipment in an “off” or “safe” state.
- Each worker shall place their own lock and tag on each of the hazardous energy sources.
Release stored energy.
- Discharge capacitors
- Release or block spring energy.
- Drain or bleed hydraulic and pneumatic lines.
- Lower suspended parts to rest positions.
Verify energy isolation.
- Do a personal check.
- Push start buttons, test circuits, and operate valves to test the system.
After Maintenance
After the job is completed, follow the safety procedures you have set up for restart, removing only your own locks and tags. With all workers safe and equipment ready, it’s time to turn on the power.
Clear the area.
- Remove all tools and replace any guards or covers
- Notify affected employees to stay clear of the work area
Remove LOTO devices.
- The person(s) who applied the locks and tags should remove their devices in reverse order of application.
Restore energy.
- Re-energize the equipment and test it to ensure it is back in working order.
- Notify affected employees that the equipment is back in service.