LOTOTO stands for Lock-Out, Tag-Out, Try-Out, which is a safety procedure used before maintenance or servicing to isolate hazardous energy.
The acronym describes three actions in specific order: lock the energy source, tag it as isolated, then try to restart it. The last step confirms zero energy before anyone touches the equipment.
While standard lockout/tagout isolates power, it doesn’t prove it worked. LOTOTO adds a hands-on test before maintenance to verify isolation.
This guide discusses the differences between LOTO vs LOTOTO, the nine-step verification procedure, and a LOTOTO checklist.
The Difference Between LOTO vs LOTOTO
LOTOTO differs from LOTO because it adds a physical test that confirms an isolation actually worked.
Standard LOTO stops at locking and tagging the energy source. It assumes the isolation is complete once the lock goes on.
Lockout tagout tryout adds a third action: attempt to start the equipment before work begins. If nothing moves, starts, or energizes, this means that the isolation passed the test. If something happens, the crew stops immediately and re-isolates the source.
This extra safety step catches faulty breakers, mislabeled valves, and isolation points that were missed.
What Are the 9 Steps of a LOTOTO Procedure?
A LOTOTO procedure generally runs through nine steps, from planning to restart.
- Prepare by identifying the equipment and every energy type it holds.
- Notify affected workers about the coming shutdown and its expected length.
- Shut down equipment using its normal stopping procedure.
- Isolate every energy source tied to the equipment, one by one.
- Lock the equipment and tag each isolation point.
- Release or block any stored energy, such as trapped air or spring tension.
- Test the equipment by attempting a normal start-up.
- If verification passes, complete the maintenance or repair work.
- Restore the equipment: remove the locks, check the area, and notify workers it is back online.
Why Tryout Verification Prevents Stored-Energy Accidents
Tryout verification prevents accidents because stored energy hides even after the main power is off.
A capacitor can hold a charge well after a breaker trips. The spring or raised component may release energy even without an input of electrical energy. Compressed air, hydraulic fluid, and gravity all store energy independent of the main switch.
A visual check alone cannot catch every one of these risks. Attempting a start-up forces the system to reveal any energy the crew missed. That single test has caught mislabeled valves and skipped isolation points before work began. Skipping the tryout means trusting an assumption instead of confirming a fact.
Is LOTOTO an OSHA Requirement?
OSHA does not use the word LOTOTO anywhere in 29 CFR 1910.147, but the tryout step is a requirement.
The standard’s six-step sequence covers preparation, shutdown, isolation, device application, stored energy release, and verification through tryout. Verification is the same action LOTOTO calls tryout, just under a different name.
According to industry sources, LOTOTO is an additional term for conventional LOTO procedures, with emphasis on the verification test.
Inspectors frequently cite facilities that skip the mandatory step of testing whether the isolation actually worked. A facility calling its program LOTOTO or LOTO is complying with the same rule either way.
What Equipment Does a LOTOTO Program Need?
A working program needs three categories of hardware: locking devices, tags, and verification tools (Lock + Tag + Verification).
Locking devices include padlocks, hasps, and lockout stations sized to the isolation points on site.
Tags attach to every lock and state who applied it and why.
Verification does not always need special tools, since many tryout checks use the equipment’s own start controls. Some facilities add voltage testers or pressure gauges to verify non-visual energy states.
A lockout station keeps all the LOTO devices organized and accessible. Group jobs need hasps with multiple padlock holes so each worker locks in individually. Keep spare tags and locks stocked so a missing item never delays a proper LOTOTO procedure.
Lockout Tagout Tryout Implementation Checklist
Use this short checklist to confirm your program covers every step correctly.
✔ ️ A written procedure exists for each machine or equipment type.
✔ All energy types are identified: electrical, mechanical, hydraulic, pneumatic, thermal, and gravity.
✔ Authorized employees are trained and can demonstrate each step.
✔ Lock, tag, and hasp inventory matches the number of isolation points.
✔ The tryout step is written into the procedure, not left as a verbal habit.
✔ Periodic inspections are scheduled at least once a year per procedure.
For example, before a scheduled maintenance starts, an electrician locks the panel, tags it, and hits the switch. When no power is generated, this means that it is safe to start repairs.
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More DetailsConclusion
LOTOTO adds an extra safety step to the standard lockout/tagout procedure. Authorized workers must test before pronouncing it safe. To ensure safety among workers, a nine-step sequence must be followed. It covers planning, isolation, locking, verification, the work itself, and restart.
The tryout step in a LOTOTO procedure is what catches stored energy and faulty isolation points before anyone gets hurt.
Bozzys supplies locks, tags, and hasps, which station facility teams need to run their LOTOTO program correctly. Our company has manufactured lockout/tagout hardware since 2011. We also hold ISO 9001, ISO 14001, and CE certifications.
Frequently Asked Questions
Does LOTOTO apply to contractors working on-site?
Yes. Contractors count as authorized or affected employees depending on their task. They must follow the host facility’s lockout/tagout tryout procedure. Many facilities require contractors to complete a short LOTOTO briefing and sign the lockout register first.
What happens if the tryout step fails during LOTOTO?
If equipment starts, moves, or shows energy during tryout, stop immediately and remove all locks and tags. Re-isolate the correct energy source, reapply lockout/tagout, and repeat the tryout step before anyone begins work.
Can one worker perform LOTOTO alone on a single-person job?
Yes, for jobs with one authorized employee and one energy source. That worker locks, tags, and tries out the equipment themselves, then keeps the only key until the job is finished.
