Lockout tagout (LOTO): what it is, the steps, the rules and a free procedure template

What is lockout tagout?

Lockout means putting a lock on an energy isolating device, such as a breaker, a disconnect switch or a valve, so it cannot be operated until the lock is removed. Tagout means attaching a tag to it that warns the device must not be operated and names who applied it.

Lockout is the stronger of the two: a lock physically stops the device being operated, while a tag only warns. That is why OSHA allows tagout alone only where a device cannot be locked, or where the tagout gives the same protection as a lock.

In the US the rule is OSHA 29 CFR 1910.147, the control of hazardous energy. In the UK and Europe the same practice is usually called safe isolation, and in the process industries it sits inside the permit to work system.

Types of hazardous energy

The lockout tagout steps

1. 01
   Prepare

   Read the energy control procedure for the equipment and identify every energy source and its magnitude.

2. 02
   Notify

   Tell the operators and everyone affected that the equipment will be shut down and locked out.

3. 03
   Shut down

   Stop the equipment by its normal stopping procedure.

4. 04
   Isolate

   Operate each energy isolating device: open breakers, close valves, disconnect drives.

5. 05
   Lock and tag

   Each worker puts a personal lock and a tag on every isolation point, or on a group lockbox.

6. 06
   Release stored energy

   Bleed, vent, drain, discharge capacitors, block or lower anything that can move.

7. 07
   Verify

   Make sure no one is exposed, try the normal start controls, and test for absence of voltage and zero pressure. Return the controls to off.

8. 08
   Work, then restore

   When the work is done, clear tools and people, refit guards, and each person removes their own lock before the equipment is restarted.

Free LOTO procedure template

• Energy control procedure: equipment, tag and location; every isolation point with its energy type, method, magnitude and how zero energy is checked; the shutdown, lockout and verification steps with a status per step; restoring energy; and sign-off.
• Lock and tag register: one row per lock, with lock and tag numbers, isolation point, who applied, verified and removed it, times on and off, and a live status.
• Drop-downs for energy type, isolation method and status. Download it and adapt it to your own procedure.

What OSHA 1910.147 requires

The OSHA standard applies to servicing and maintenance in general industry, where unexpected start-up or release of energy could injure workers. An employer must have an energy control program with:

• Written procedures for each piece of equipment, with the steps to shut down, isolate, block, secure and verify, and to remove locks.
• Lockout and tagout devices that are durable, standardised, substantial enough not to be removed without excessive force, identify the person who applied them, and are used for nothing else.
• Training: authorised employees learn to recognise energy sources and to isolate them; affected employees learn what the procedure is and never to restart locked-out equipment.
• Periodic inspection of each procedure at least once a year, by an authorised employee other than those using it.
• Rules for special cases: group lockout, shift changes, outside contractors, and removing a lock when the person who applied it is not available.

Construction and electrical work are covered by other OSHA rules (including 1926 subpart K and 1910 subpart S), and NFPA 70E sets out how to create an electrically safe work condition.

Lockout tagout in the UK and Europe

UK law does not use the term lockout tagout, but the duty is the same. The Provision and Use of Work Equipment Regulations 1998 require means to isolate equipment from its energy sources, and the Electricity at Work Regulations 1989 require dead working wherever possible, with precautions against equipment being made live. HSE guidance HSG253, the safe isolation of plant and equipment, sets out isolation standards for the process industries.

In Europe, EN ISO 14118 covers the prevention of unexpected start-up of machinery, and in Canada CSA Z460 covers the control of hazardous energy.

Lockout tagout during commissioning

Commissioning is when isolation is most complicated. Systems are energised for the first time, construction and commissioning crews work side by side, and the boundary between a live system and one still being built moves every day.

• Isolate by system. Isolations follow the system and subsystem boundaries of the completions plan, so everyone knows which part of the plant has been handed to commissioning.
• Energise under control. First energisation of a switchboard or a process system is a planned event with its own procedure, after the system has passed mechanical completion.
• One isolation register. Commissioning keeps a single register of every isolation, lock and permit, transferred to operations at handover.
• Permit to work. On process plants and offshore, LOTO sits inside the permit to work system, with isolation certificates per job.

See mechanical completion, the pre-startup safety review and commissioning 101 for the steps around it.

Common lockout tagout mistakes

• Isolating the electrical supply and forgetting stored, pressure or gravity energy.
• Skipping the try-out, so a failed isolation is only found when someone is already inside.
• One lock for a whole crew instead of a personal lock per worker or a group lockbox.
• Tags used where a lock would fit, or tags without a name and date.
• Procedures that are generic rather than written for the actual equipment, and never reviewed.
• Locks cut off at shift change instead of being transferred under the procedure.