What is Lockout Tagout used for?

In it’s most simple form Lockout Tagout (LOTO) is a system used to protect employees from serious injury or death by isolating the energy source of a machine or electrical circuit to prevent unexpected start-up whilst a worker is repairing or servicing it.

When to use Lockout Tagout

LOTO should be used to shut down machinery in the workplace that has a hazardous energy source, for example electricity, when it is being serviced, maintained or repaired. This will also include (but is not limited to) activities regarding installation, inspection and cleaning. Additionally, it is used to ensure complete isolation of electrical circuits. LOTO ensures complete shutdown of the machinery/ electrical circuit and should prevent accidental machine start-up or energy discharge either whilst it is broken or being repaired. Accidental machine start up whilst there is a worker repairing the machine can lead to severe injury or death.

Injuries arising from an electrical power source may include shock or electrocution. When working in a large factory the power source for a piece of machinery may be in a different room to the piece of machinery itself. LOTO therefore adds another layer of security in assuring that the machine is not inadvertently switched on. LOTO must also be used with cord and plug equipment that has another energy source, for example a capacitor.

Lockout Tagout in more detail

LOTO has 2 key points to it:

Lockout refers to securing the Energy Isolating Device of a machine or electrical circuit (examples of which include circuit breakers and line valves) in a safe position. This will normally involve putting the Energy Isolation Device into the ‘off’ position. It is then secured into this position with a physical restraint (the lockout device). There are a wide range of devices available that can fit over different shaped switches, valves and effectors. For electrical power sources there are specific panel lockouts to keep the panel door locked and prevent the removal of the cover.

All devices are purposefully designed to be resistant to force and therefore cannot be easily removed. They are often brightly coloured, most commonly red, ensuring that they are easily seen. Only the authorised worker on the machine should hold the key to the padlock securing the device and it will be he/she who should unlock the padlock once the repair is complete. For machinery where several individuals may be working on the repair in different areas of the building there are group lockout keys available that means each worker must lock and unlock their own padlock on the device prior to the machine being started again.

Tagout should always follow lockout. The tag should be placed on the lock and display why the machinery is locked, the date and time it was locked and the name of the person authorised to carry out the repair.

The Lockout Tagout procedure

The LOTO procedure should be known and understand by both those who will use it and carry out the repair (the authorised person) and those who may work with or near the machinery that will be shut off (the affected person).

The LOTO procedure is as follows:

  • 1. Inform those affected that the machinery is to be shut off
  • 2. Locate all energy sources to the machine
  • 3. Isolate all energy sources to the machine
  • 4. Carry out LOTO
  • 5. Test to prove that LOTO is effective

Employers and employees are both responsible for ensuring that they know, understand and adhere to the LOTO procedure for their place of work. By using LOTO, the risk of injury or death to the worker repairing the machinery is dramatically reduced.