LOTOTO: The Lock Out, Tag Out, Try Out Procedure Explained

Some of the most serious workplace injuries happen when a machine starts, moves or releases energy while someone is working on it. Isolation procedures exist to stop that. The “try out” step, testing that isolation has actually worked, is what turns a lock and tag into a verified safe state. This guide covers what LOTOTO is, the step-by-step procedure, common failures and how to keep isolation records.

Why isolation matters

Under WHS laws, businesses must manage risks from plant, including during installation, maintenance, cleaning and repair. The WHS regulations require plant to be isolated from energy sources, so far as is reasonably practicable, before this work is done, so it can’t be started or operated unexpectedly. Safe Work Australia’s model Code of Practice on managing the risks of plant in the workplace gives guidance on isolation procedures. Check with your state or territory regulator for the rules that apply to you.

Energy sources to isolate

• Electrical: mains supply, batteries and capacitors
• Mechanical: moving parts, flywheels, springs and gravity (raised loads)
• Hydraulic and pneumatic: pressure in lines, cylinders and accumulators
• Thermal: hot or cold surfaces, steam
• Chemical: process lines and vessels

Many pieces of plant have more than one energy source. Every one of them needs isolating.

The LOTOTO procedure

1. Prepare. Identify all energy sources and isolation points, using the plant’s isolation procedure, and tell affected people.
2. Shut down. Stop the plant using its normal controls.
3. Isolate. Operate each isolation point, such as switches, valves and breakers, to cut off every energy source.
4. Lock and tag. Each worker applies their own personal lock and a tag showing their name, the date and the reason.
5. Release stored energy. Bleed pressure, discharge capacitors, lower or block raised parts, and let moving parts stop.
6. Try out. Test that the plant can’t start or operate, for example by trying the start button, then return controls to off.

When work is finished, check the plant is clear of tools and people, refit guards, and remove locks and tags in a controlled way before restoring energy.

Common failures

• Missing an energy source: isolating the main power but not hydraulic pressure or a second supply.
• Skipping the try out: assuming the isolation worked without testing.
• Shared locks: one lock for a whole crew, so workers aren’t personally protected.
• Out-of-date procedures: isolation points changed but the procedure didn’t.
• Shift changes: locks removed or handed over without a controlled process.
• Missing equipment: not enough locks, tags or lockout devices at the point of work.

See our guide to machine guarding.

LOTO vs LOTOTO

Digital isolation records

With DIGI CLIP, workers complete isolation checklists on a phone: energy sources identified, isolation points operated, locks applied, stored energy released and try out completed, with photos. Each form is location- and time-stamped. Problems, such as a missing lockout device or an out-of-date procedure, become actions in the Action Log, and supervisors can review isolations across sites.

Illustrative scenario: a missed hydraulic isolation

A fitter is isolating a baler for blade maintenance at a recycling depot. Working through the isolation checklist in DIGI CLIP, he reaches the stored energy step and finds the hydraulic accumulator isn’t listed in the plant’s procedure. He bleeds it down before starting work and raises an action to update the procedure, which is closed out with the revised version the following week.

This scenario is illustrative. It shows how a business could use DIGI CLIP and is not an account of a specific customer.

See also our guide to daily plant equipment safety checks.