Lockout Tagout Tryout: Why it is Crucial for Safety

lockout tag attached on padlock and hasp

It was supposed to be a regular working day for workers from an electrical company, but one employee did not return home alive that day.

The reason for this fatality is that earlier the previous day, the electrical power company had installed the meter in the wrong house. This means that the workers were unaware that power had been applied to a house intended to be free of electricity.

In a similar story, an electrical engineer went to work like any other day but went home seriously injured after falling from a height due to a high voltage shock. As part of the procedure, the engineer locked the equipment before he started the repair, but the control switch malfunctioned and accidentally re-energized the equipment.

These incidents are totally avoidable. The first one could have been prevented through an efficient implementation of lockout tagout procedures. However, the second story goes beyond applying lockout measures; the incident could have been avoided by verifying or trying out the equipment before performing repair.

This article discusses the concept of lock out tag out try out, or LOTOTO, and why it is crucial for ensuring optimum safety in the workplace.

What is Lock Out/Tag Out/Try Out?

Most people in the industry are familiar with lockout tagout (LOTO) but not with lock out/tag out/try out (LOTOTO). Like lockout tagout, LOTOTO protects workers by preventing accidental energizing and unauthorized reactivation of equipment, machines, and other stored energy sources while service, maintenance or repair is being done. The difference is that LOTOTO emphasizes the importance of testing controls and equipment before performing any task.

Understanding the difference between lockout, tagout, and tryout will provide a better perspective on how LOTOTO works.

Lock Out

In a lockout, a device specifically used for energy control procedures is placed on the energy isolating device, such as a valve, switch, or circuit breaker in accordance with a specific procedure. The primary purpose of a lockout, as noted by OSHA’s Control of Hazardous Energy standard, is to ensure that the energy isolating device and the equipment being controlled cannot be operated until the lockout device has been removed.

Tag Out

Tag out refers to the labeling process that should always be done after a lockout procedure. In practice, a tag is placed on an energy isolating device alongside the lockout devices in accordance with a specific lock out tag out procedure. According to OSHA’s Control of Hazardous Energy standard, the primary purpose of a tagout is to indicate that the equipment, machine, or energy sources being controlled may not be operated until both lockout and tagout devices have been removed. Tags also provide vital information such as the lockout procedures being done on the equipment, the LOTO device owner, and the issues being solved.

Try Out

The tryout or verification step involves testing controls and attempting to operate the equipment after applying a LOTO procedure. OSHA’s lockout tagout toolbox talk noted that this procedure tests if the machinery and equipment has been properly locked out.

Why is “Tryout” essential?

what is lototo at work

Going back to the story of the electrical engineer who suffered serious injuries due to a high voltage shock, if a tryout procedure had been done before the engineer performed a task, injuries could’ve been avoided.

Companies often forget that verifying isolation is just as crucial as the lockout procedure itself. LOTO procedures prevent accidental re-energization and unauthorized reactivation of stored energy sources, equipment, or machine. However, in cases where, like in the story, a control switch malfunctioned, applying a LOTO procedure may not be enough to achieve optimum safety.

If a locked out energy isolating device malfunctions, the equipment could accidentally start up, leading to serious injuries or even fatalities. For this reason, testing isolation devices and equipment before any task is performed is essential for safety. This step identifies if there are any faults with the isolation point and if it is safe to continue performing any task with the equipment, machine, or energy source. Such a step can help the employee be more confident about his safety while performing service or maintenance.

Basic Components of LOTOTO


Companies need to establish a clear lock out tag out try out policy which includes job titles with specific roles and responsibilities. The LOTOTO policy should be a zero-tolerance policy because lives are on the line with every failed adherence. It should also be supported by management and implemented by appropriate department employees.

LOTOTO Training

As stated by OSHA, employers need to train their workers to make sure that they know, understand, and follow the provisions of the hazardous energy control procedures or lockout tagout procedures. Establishing a LOTOTO program, therefore, should also be accompanied by the necessary training to ensure that authorized employees understand and follow the requirements of the procedure, especially when it comes to the tryout or verification step.

Effective training should be delivered by an authorized instructor who would be able to detail the process for locking out and isolating equipment. The instructor should be able to train employees in the whole process of lockout, tagout, and tryout.


Basically, implementing LOTOTO in the workplace means emphasizing the importance of the tryout step. Companies should update and upgrade their LOTO program by adding the tryout procedure.

Steps in Implementing LOTOTO

steps in implementing lototo
  1. Prepare: Review the Work Order and provide a pre-job briefing to workers involved with the equipment. Review the machine, equipment, and process, including risk assessment, then finalize the required paperwork, permit, or schedule of the procedure.

  2. Notify: Notify all affected employees and individuals that the equipment will be locked out or isolated, advise them to stay away from the equipment, and instruct them not to energize or operate the equipment.

  3. Shutdown: Referring to the specific LOTO procedure, shut down and de-energize the machine or equipment. This should be performed in an orderly manner to avoid hazards.

  4. Isolation: Using appropriate isolation points, isolate the machine or equipment from hazardous energy. Also, isolate secondary energy sources that might interfere with the isolation procedure. In case of electrical defects, isolate the equipment through its energy isolation devices, not with its controls.

  5. Apply locks and tags: Apply LOTO locks to each energy isolation device. As a general safety rule, “one lock, one person, one energy source” must be observed. Add a LOTO tag appropriate for the isolation point. All workers working on the equipment must also add their own lock and tag.

  6. Zero Energy State: Control all hazardous energy at a zero state and ensure that no energy remains in the machine.

  7. Tryout: Attempt to operate the machine or equipment through its operating controls to make sure that it has been fully de-energized, locked out, and will not accidentally operate.

  8. Perform task: Start and complete the planned task, such as maintenance and repair, while following safety protocols and procedures. If accidental re-energization occurs: immediately stop the task, withdraw all workers, implement control measures, report any near hit, and investigate the accident.

  9. Inspect and restore: Inspect the area and equipment, secure the guarding in place, and notify all affected individuals that energy will be restored. Then, remove all personal lockout and tagout devices, restore devices to operating position, verify that all are operating properly, then notify higher-ups regarding the completion of the procedure. Lastly, complete all needed paperwork or permits.

Go home safe today: Lock, Tag, and Try

The concept of LOTOTO may sound new to some, but leading organizations are now adopting this upgraded safety procedure. Due to serious incidents caused by failure to check or test that all isolations and lockouts were performed properly, industries have started to invest in upgrading their LOTO program by including the “tryout” procedure.

The tryout or verification procedure may be the most important step to ensure workers are working on equipment, machine, or energy source in a safe and energy-free state. Help your employees go home safely today. Lock, tag, and try!

The material provided in this article is for general information purposes only. It is not intended to replace professional/legal advice or substitute government regulations, industry standards, or other requirements specific to any business/activity. While we made sure to provide accurate and reliable information, we make no representation that the details or sources are up-to-date, complete or remain available. Readers should consult with an industrial safety expert, qualified professional, or attorney for any specific concerns and questions.


Shop Tradesafe Products

Author: Herbert Post

Born in the Philadelphia area and raised in Houston by a family who was predominately employed in heavy manufacturing. Herb took a liking to factory processes and later safety compliance where he has spent the last 13 years facilitating best practices and teaching updated regulations. He is married with two children and a St Bernard named Jose. Herb is a self-described compliance geek. When he isn’t studying safety reports and regulatory interpretations he enjoys racquetball and watching his favorite football team, the Dallas Cowboys.