Lockout/tagout (LOTO) is the safety procedure that isolates machines from every hazardous energy source and locks them in a safe state before maintenance or servicing work begins, so equipment cannot start up or release stored energy while someone is working on it. In the US it is governed by OSHA standard 1910.147 (control of hazardous energy); EU countries enforce equivalent requirements through national law under the Use of Work Equipment Directive.
Machines store and carry energy in more forms than the obvious electrical supply: pneumatic and hydraulic pressure, spring tension, raised loads and counterweights, rotating mass, thermal energy, and chemical feeds. An unexpected start-up or a release of stored energy during servicing is one of the most common causes of serious injury in maintenance work. LOTO makes the safe state physical and personal: each worker applies their own lock, and the machine cannot run until every lock is removed.
Restoring service reverses the sequence: tools cleared, guards refitted, people accounted for, locks removed by their owners, and affected staff notified before restart.
Authorized employees are trained to perform the lockout and are the only people who apply and remove their own locks. Affected employees operate or work near the equipment and must be notified when a lockout starts and ends. Group lockouts on larger jobs use a lockbox or group hasp so every worker still holds a personal key. A supervisor-controlled lock removal (when a worker leaves site with the key) must follow a strict documented exception procedure.
A packaging line has 6 isolation points (two electrical disconnects, two pneumatic valves, one steam valve, one gravity block). Applying, verifying, and later removing a full lockout averages 4 minutes per point, so about 24 minutes per job before wrench time even starts. With 30 locked-out jobs a month, that is 12 hours of planned, unavoidable procedure time. Planners who ignore it systematically underestimate job duration and then wonder why wrench time looks low; planners who build it into work order estimates get realistic schedules and no pressure to shortcut the procedure.
LOTO works best when it is part of the job plan, not a separate binder. Equipment-specific isolation steps can be attached to recurring jobs in a CMMS, so every preventive maintenance work order carries the current procedure, and completion records show the lockout was performed. Dedicated permit and isolation tools exist for complex sites (see our review of digital LOTO software), and higher-risk jobs typically also require a permit to work. Fabrico's role is the maintenance backbone: work orders with the right procedure attached, asset history showing what was done, and real-time visibility of which equipment is stopped.
Lockout physically prevents energization with a lock on an isolation device. Tagout only warns with a tag and relies on people respecting it. Tags alone are permitted only where a device cannot accept a lock, and they must be backed by additional protective measures.
Yes, whenever someone bypasses a guard or places part of their body where they could be injured by unexpected movement. Some routine, repetitive minor servicing may be exempt if it is performed with effective alternative protection designed into the machine, but that exemption is narrow and must be justified.
At least annually (OSHA requires a periodic inspection of each energy control procedure) and immediately after any equipment modification, relocation, or incident. The review should compare the written isolation points against the machine as it exists today.
Put current procedures on every work order and keep a full history of what was done on each asset. Book a Fabrico demo.
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