Staying Safe At Work: Understanding The LOTOTO Procedure

In the world of industrial maintenance and repair, safety is not just a concern; it’s the absolute priority. When equipment needs servicing, the potential for unexpected startup or the release of stored energy—like electricity, steam, hydraulics, or even springs—can be fatal.1 This is where the LOTOTO procedure comes into play, a simple yet critical framework designed to save lives.2 It stands for Lock-Out, Tag-Out, Try-Out.

The LOTOTO procedure is essentially a methodical way of ensuring that dangerous machinery is completely isolated from all energy sources and cannot be accidentally re-energized while a worker is performing maintenance.3 Think of it as putting a safety bubble around the equipment until the work is finished.

Step 1: Preparation
Before anyone even thinks about turning a wrench, the authorized person must know exactly what they are dealing with. This involves identifying the specific machine or equipment that needs service and, more importantly, finding all the potential energy sources.4 A machine might have electrical power, compressed air lines, or stored pressure in hydraulic cylinders.5 You need to know every single one. Crucially, you must also look up the machine-specific procedure for shutting it down safely. Not every machine powers down the same way.

Step 2: Notification
Safety is a team effort. The next immediate step is to notify all "affected" employees—anyone who operates the machine or works in the immediate area—that the equipment is going to be shut down.6 This prevents confusion, helps them plan their work around the interruption, and most importantly, ensures no one attempts to restart the machine during the maintenance window. Transparency is key to preventing accidents.

Step 3: Shutdown
Now, the authorized employee shuts the equipment down.7 This must be done using the standard, defined shutdown process for that specific piece of machinery.8 It's important not to rush this step; the equipment should be brought to a complete stop safely and methodically.

Step 4: Isolation
This is where the 'Lock-Out' and 'Tag-Out' part begins. Once the machine is off, all identified energy-isolating devices—such as circuit breakers, line valves, or control switches—must be deactivated to fully disconnect the machine from its energy sources.9 For instance, an electrical disconnect switch is opened, or a valve is closed.10

Step 5: Lock-Out and Tag-Out
The core of the safety process is applying a 'lock' and a 'tag' to each energy-isolating device.11

Lock-Out: A personal lock, usually a dedicated padlock, is physically placed on the energy-isolating device.12 This lock is standardized, durable, and unique to the person who is doing the work. The goal is to physically prevent the device from being moved back to the 'on' or 'energized' position.13 The key to that lock stays with the authorized employee for the entire job.14
Tag-Out: A warning tag is attached to the lock.15 This tag is a communication tool. It clearly states that the equipment is out of service, why it is locked out, and—most importantly—identifies the name of the person who applied the lock and the date.16 The tag’s warning is simple: DO NOT OPERATE.
If multiple workers are involved, each person must place their own personal lock on a group lockout device, ensuring that no one can remove the isolation until all workers are finished and have removed their personal locks.17

Step 6: Control Stored Energy
Even after being shut down and locked out, a machine can still hold dangerous stored or residual energy.18 This is a critical safety hazard. This energy must be neutralized or relieved.19 This might involve bleeding residual pressure from a hydraulic line, venting compressed air, blocking parts that could drop due to gravity, or allowing high-temperature elements to cool down.20

Step 7: Try-Out (Verification)
This is the ‘T’ that makes the procedure a LOTOTO procedure and is arguably the most vital step. The authorized employee must verify the isolation is successful.21 They do this by attempting to start the machine using the normal operating controls (like pressing the 'Start' button).22 If the equipment has been correctly locked and isolated, absolutely nothing should happen. If it attempts to start, the procedure has failed, and they must immediately return to Step 4. After the Try-Out, the controls must be returned to the 'off' position.23 This verification step confirms a zero energy state.24

Step 8: Perform the Work and Restore Service
Only once the Try-Out is successful can the maintenance or repair work safely begin. When the job is complete, the authorized employee must inspect the area to ensure all tools have been removed, all guards are put back in place, and the equipment is structurally whole.25 They then notify the affected employees that service will be restored.26 Finally, the authorized person removes their personal lock and tag. The equipment can then be safely re-energized and returned to operation.27 The removal of the lock is solely the responsibility of the person who put it on.