Lockout/Tagout (LOTO) is a safety procedure that ensures hazardous energy sources — electrical, hydraulic, pneumatic, mechanical, thermal, and chemical — are fully isolated and unable to release before maintenance or servicing work begins. According to OSHA's Control of Hazardous Energy standard (29 CFR 1910.147), failure to properly control hazardous energy accounts for nearly 10% of serious workplace accidents in general industry — and is a leading cause of fatalities in manufacturing, utilities, and oil and gas environments. The National Institute for Occupational Safety and Health (NIOSH) estimates that approximately 3 million workers in the United States alone perform servicing and maintenance work that requires LOTO protection each year.
The good news is that LOTO incidents are almost entirely preventable. When your team follows a well-designed LOTO programme — with documented procedures, trained technicians, the right equipment, and a system to enforce compliance — the risk of accidental equipment startup or energy release during maintenance drops to near zero. This guide walks through the best practices that keep maintenance technicians safe every time they service hazardous equipment.
Lockout/Tagout works on a simple principle: before anyone works on equipment, every energy source feeding that equipment must be physically isolated (locked out) and labelled (tagged out) to prevent re-energisation until the work is complete and all personnel are clear. A lock is applied to each isolation point — circuit breaker, valve, disconnect switch — by the authorised technician performing the work. Only that technician holds the key. A tag is attached to communicate the reason for the isolation and who applied it.
The stakes are high. Stored energy in a capacitor bank can deliver a lethal shock minutes after power is switched off. A pneumatic cylinder under pressure can drive a ram with enough force to crush a hand. A conveyor belt that appears stopped can restart the moment someone resets a tripped overload relay. LOTO is the barrier between your technicians and all of these hazards.
OSHA 1910.147 requires every employer to establish a written energy control programme with specific documented procedures for each piece of equipment. Here is the core six-step sequence that underpins every compliant LOTO procedure:
Before touching the equipment, identify all energy sources — primary and residual — and locate every isolation point. Review the equipment-specific LOTO procedure. Confirm you have the correct locks, tags, and any additional hardware (circuit breaker lockouts, valve lockout hasps, cable lockouts) needed for this job. Notify affected employees that the equipment is being taken out of service.
Use the normal stopping procedure to bring the equipment to a complete stop. This is not the lockout step — it is simply stopping the machine through its standard controls before isolating the energy supply.
Operate every isolation device to disconnect all energy sources. For electrical equipment, open the circuit breaker or disconnect switch. For pneumatic systems, close the isolation valve upstream of the equipment. For hydraulic systems, close the hydraulic supply valve and open the return to tank. Each isolation point gets its own lock.
Apply your personal lock to each isolation device, then attach a completed tag. The tag must include your name, the date, the reason for the lockout, and a warning against operating the isolation device. If multiple technicians are working on the same equipment, each applies their own personal lock using a hasp — all locks must be removed before the equipment can be re-energised.
This step is where many LOTO incidents occur. Even with energy sources isolated, residual stored energy can remain: bleed pneumatic lines, cycle hydraulic valves to release pressure, block suspended loads, discharge capacitors, and allow heated surfaces to cool to safe temperatures. Verify that each stored energy source has been fully neutralised before proceeding.
Test before you touch. Use a calibrated voltage tester to confirm electrical circuits are dead. Attempt to start the equipment using its normal controls to confirm it will not start. Check pressure gauges to confirm pneumatic and hydraulic systems are at zero. Only after this verification step should any maintenance work begin. Document the verification result as part of the work order record.
Generic LOTO procedures are not enough. OSHA requires a documented procedure for each piece of equipment that has more than one energy source, or where the isolation sequence matters. A CNC machining centre has different isolation requirements to a conveyor system or a paint spray booth — and the technician servicing each one needs a procedure written specifically for that machine.
Machine-specific procedures should include a diagram or photograph of each isolation point, the type of lock and device required at each point, the sequence of isolation steps, the method for verifying zero energy state, and any special precautions for that equipment type. These procedures belong in your document management system — attached to the specific asset record — so every technician can access the correct procedure from a mobile device before starting work, even if they have never serviced that piece of equipment before.
When you store LOTO procedures in a CMMS alongside work orders, there is no excuse for a technician to start a job without the right procedure in hand. Every time a work order is raised for a lockout-required task, the system can prompt the technician to review the attached LOTO procedure and confirm acknowledgement before the job is marked in progress.
OSHA 1910.147 requires three categories of training for LOTO programmes. Understanding the gap between what the standard requires and what most sites actually deliver is the first step toward closing it.
These are the technicians who perform the lockout — they apply and remove locks. Authorised employees must be trained to recognise hazardous energy sources on the specific equipment they service, understand the type and magnitude of energy present, and be competent to apply the equipment-specific LOTO procedure correctly. This training must be documented and refreshed whenever procedures change or the employee's job role changes.
These are workers who operate equipment that may be locked out, or who work in the area where lockout is in effect. They do not apply locks, but they must understand why the equipment is locked out and that they must never attempt to restart it or remove a lock that is not theirs.
Anyone who works in an area where LOTO procedures are used must receive general awareness training — enough to understand the purpose of tags and locks and to stay clear of locked-out equipment.
The most common training gap is specificity: organisations deliver generic LOTO training that does not cover the actual equipment on their site. A technician who understands the concept of lockout but has never been shown the isolation points on the specific press or compressor they are about to service is still at risk. This is also a gap that ISO 45001 (Occupational Health and Safety Management Systems) explicitly calls out — it requires that competency is established for specific tasks, not just general topics. Use your maintenance checklists to embed LOTO verification steps directly into the work order — so training is reinforced at the point of execution, not just in a classroom.
When multiple technicians or contractors work on the same piece of equipment simultaneously, each person must apply their own personal lock to the isolation hasp. The equipment cannot be re-energised until every lock has been removed — which means every technician has confirmed their work is complete and they are clear of the hazard zone. This is the fundamental protection that group lockout provides: no single person can inadvertently energise a system while another person is still working on it.
Complex LOTO scenarios — such as maintenance on a production line with 20 or more isolation points, or work on interconnected systems where isolating one piece of equipment affects others — require a written group energy control procedure and a designated LOTO coordinator who is responsible for managing the sequence of isolation and re-energisation. These complex procedures should be reviewed and approved before the job starts, not improvised in the field.
Your permit to work software is the right tool for managing complex LOTO scenarios. A digital permit captures the specific isolation requirements, records which locks have been applied and by whom, requires supervisor authorisation before work begins, and provides a clear re-energisation checklist at job completion. This creates an auditable record of every step — critical evidence if an incident occurs or a regulator asks for documentation of your energy control programme.
A CMMS does not replace a LOTO programme — but it makes every part of it more reliable. Here is how a well-configured CMMS like Cryotos supports LOTO compliance across your facility:
You can also use your work order management system to flag which work orders require a LOTO permit before a technician can be assigned — preventing the common problem of a job being started before the correct safety documentation has been issued.
Lockout uses a physical lock to hold an isolation device in the safe position so it cannot be operated. Tagout uses a warning tag to communicate that the equipment must not be operated, but without a physical lock. OSHA requires lockout wherever equipment can be locked — tagout alone is only permitted where the equipment design does not allow a lock to be applied. In practice, lockout provides a higher level of protection because a tag can be removed or ignored, whereas a lock physically prevents operation.
Under OSHA 1910.147, all employees who work in areas where LOTO is used need some level of training. Authorised employees (those who apply and remove locks) need thorough equipment-specific training. Affected employees (those who operate or work near locked-out equipment) need training on why LOTO is in place and what they must not do. Other employees who may encounter locked-out equipment need general awareness training.
OSHA requires a periodic inspection of the energy control programme at least annually, including a review of each machine-specific procedure with the authorised employees who use it. Procedures must also be reviewed whenever the equipment is modified, the energy sources change, or an incident or near-miss occurs that involves a locked-out system. Document every annual review with the date, the equipment reviewed, and the names of the employees who participated.
Yes — and they should. Every person working on locked-out equipment must apply their own personal lock. If a contractor is performing maintenance on your site, they must apply their own lock to the group hasp alongside your employees' locks. Never allow a contractor to rely on a host company's lock for their personal protection. Confirm that your contractor management process requires contractors to arrive with their own LOTO equipment and evidence of current LOTO training before they start any work.
LOTO incidents are among the most serious — and most preventable — safety events in industrial maintenance. A well-documented programme, trained technicians, and the right systems to enforce compliance at the point of execution are all it takes to drive the incident rate to zero. Cryotos helps maintenance teams build that system — with digital permits, linked LOTO procedures, mandatory checklists, and certification tracking built directly into the work order workflow. If your team is still relying on paper-based LOTO records or manually tracking certification renewals, it is worth taking a closer look at how maintenance management software can close those gaps before they become incidents.
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