LOTO and LOTOTO: What are the differences? When should the "trial" function be added?
In the field of industrial safety, LOTO (Lockout/Tagout, Locking Out and Tagging Out) is almost a universally known concept. However, in recent years, more and more enterprises and safety experts have begun to advocate an upgraded version - LOTOTO, which is the addition of a "T" after the locking out and tagging out: Tryout (trial/verification). This extra "T" may seem like just an additional step, but in fact, it is the dividing line from "paper safety" to "real safety". 
This article will systematically clarify the core differences between LOTO and LOTOTO, and specifically address a frequently overlooked issue in practical operations: when should the "trial" step be added, and how should it be correctly executed?
LOTOTO: What does the extra "T" signify?
2.1 Definition of LOTOTO
LOTOTO = Lockout / Tagout / Tryout, which means after the locking and tagging process, an explicit "trial" (Tryout) action is added. 
This "Tryout" does not mean "testing to see if the equipment works properly", but rather the opposite - after the locking is completed, attempt to start the equipment, verify that it cannot operate, thereby confirming that the energy isolation has truly taken effect. 
2.2 The Complete Process of LOTOTO
Based on LOTO, LOTOTO has strengthened the verification steps into an independent process that cannot be skipped and has clear operational guidelines: 
Notice → 2. Shut down → 3. Isolate → 4. Lock and tag → 5. Release residual energy
Trial and Verification (Trial Operation Verification) - Attempt to start the equipment and confirm no response
Confirm safety → Start operation
The core difference lies in step 6: The verification of LOTO may only be "observed", while the Trial and Verification of LOTOTO must be "tested".
Standard execution steps of Trial and Verification
The first step: Confirm that personnel have evacuated the dangerous area 
Before attempting to start the equipment, it is necessary to ensure that all personnel have left the dangerous movement area of the equipment. The purpose of the trial run is to verify that "the equipment is not moving", but if the isolation fails and the equipment suddenly starts - if personnel are still in the dangerous area, the verification process itself becomes an accident. 
Safety rule: Clear the area first, then test the equipment. 
Step 2: Attempt to start the device normally 
The normal startup control of the equipment (such as the start button, switch, remote control, etc.), and observe whether the equipment responds in any way - the motor rotates, the cylinder extends and retracts, the valve operates, the indicator lights come on, etc. 
Step 3: Observe and make a judgment 
No response from the equipment → The isolation is effective and safe operation is possible
Any movement or indication from the equipment → The isolation has failed! Immediately stop the operation and recheck the energy source and isolation points 
After the trial run is completed, the control will be reset to the "off/stop" position to prevent the equipment from suddenly starting up when recovering energy in the future. 
Step 5: Record the verification results 
Record "Tryout has been conducted, the equipment did not respond, and the verification was successful" on the LOTO license or checklist, and sign for confirmation.