What is a Lockout/Tagout procedure?

Lockout/ Tagout (LOTO) is a common practice followed during maintenance or service of equipment or machine to control hazardous energy and to ensure that equipment remains shutdown and de-energized until the maintenance work is completed. When done properly LOTO prevents accidental energizing of equipment and protects the workers from harm. 


What is hazardous energy?

Any form of energy that has the potential to harm personnel can be called hazardous energy. They can be of any form, including obvious energy sources like heat in a furnace, rotating flywheel, or electricity and hidden energy sources like a loaded spring or pressurized equipment. Mechanical, electrical, hydraulic, pneumatic, nuclear, thermal, chemical are the different forms of hazardous energies that can be commonly found in industries. During a maintenance or service operation, an accidental startup or the release of stored energy from equipment can be devastating to the workers who are nearby. 


A Lockout/Tagout procedure can be successfully implemented by following the steps listed below.

  1. Plan and prepare 
  2. Notify 
  3. Shutdown 
  4. Isolate 
  5. Lockout/Tagout 
  6. Verify isolation
  7. Keep it under control
  8. Record, review, and repeat


It goes without saying that planning is the first and foremost step for successfully carrying out a process. Plan, investigate, and prepare a detailed equipment-specific LOTO procedure that must be implemented during any repair or maintenance work on that equipment. A step by step plan with pictures can be an interactive way of listing the correct procedures for shutting down and starting the machine back up after maintenance. It is also important to address any secondary sources of energy like heat or electricity that needs to be isolated. Document these procedures and ensure that they are readily available for the management and employees. Furthermore, hazardous energy control related training must be provided to all employees working on equipment or machinery. OSHA 1910.147 provides the guidelines for the control of hazardous energy (lockout/tagout).



When a LOTO procedure is going to implemented in a workplace, all the associated employees must be notified. The employees can be notified by displaying signboards and also through toolbox talks.


After notifying the affected employees, the machine, or equipment to be serviced or maintained is shut down. At this stage, the power source for the equipment still remains connected and active. This will be taken care of in the next step.


This step is done to ensure that the equipment is cut off from the power sources to avoid accidental energization during the maintenance or service process. The process of isolation can involve simple tasks like shutting a valve or switching off a breaker.


With the power source disconnected from the machine, the energy source can now be actually locked out by attaching specific LOTO devices to the energy isolating devices or to the cabinet of the power source. A tag containing the name of maintenance personnel and additional information about the process is applied on the device as well. In some cases, where a lockout is not possible, a tag-out device must be securely fastened as close as safely possible to the energy isolating device. The tag-out device or simply a tag must be clearly visible and should alert anyone to the hazard of re-energization.


Even though the machine is completely isolated from the energy source, there might be some residual or stored energy present within the machine. Moreover, there might even be a secondary source of energy that could’ve been missed out. Check for such sources and verify that the machine is completely de-energized by draining the residual or stored energy. A lockout can be re-verified by attempting to start the machine. Ensure that the employees are at a safe distance away from the machine while doing so, to protect them from any potential danger. With this step, the LOTO procedure is successfully completed. But there are few more steps that are needed to be followed to successfully implement a LOTO procedure every time. 


The locked out and tagged out equipment must remain in that condition across shifts till the maintenance or service work is completed and the equipment is permitted for regular operation. This prevents workers from different shifts from accidentally energizing the equipment. During a change of shift, if separate locks or tags are used, the person responsible for implementing lockout/tagout and the person and the person responsible during the next shift must be present.



As mentioned earlier, these step by step procedures must be recorded and maintained for individual machines or equipment. However, the equipment and its operating procedures change over time and these changes should be reviewed on a regular basis. To maintain an accurate LOTO procedure it is necessary to review them from time to time. Better ideas with accurate descriptions can be implemented while creating these plans, these plans not only help improve the procedures followed but also help improve the safety and wellbeing of the workplace. 

Written By –
Davis Franco
UPES, Dehradun

Leave a Reply

Your email address will not be published. Required fields are marked *