Lockout/Tagout procedure: how to implement it?

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Too many accidents occur during maintenance and repair work on machines. To avoid them, lockout/tagout procedures must be known by heart. Here's how to do it.


Accidents during maintenance operations often occur as a result of equipment that has not been deactivated or circuits that have not been purged. Indeed, the operator has to access the heart of the machine with, potentially, residual energy. To avoid danger, it is recommended to lockout and then switch the device on again.



Lockout/Tagout is a safety procedure. It aims to neutralise energy sources during a maintenance or repair operation of a machine. Repairs are then carried out safely, without the device restarting. Indeed, in most cases, the employee believes he is safe simply because the work equipment has been stopped.


The lockout/tagout procedure is stated in the NFC 18-510 standard as well as the 2009/104/CE directive about the minimum safety and health requirements for the use of work equipment.


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Preparation of the lockout/tagout


First of all, it is essential to prepare the lockout by identifying the type of operation to be carried out, the type of energy running (electrical, mechanical, hydraulic...) as well as the risks associated with the execution of this task. Likewise, it is necessary to identify the resources required to carry out the repairs activities as well as to entrust the tasks to trained personnel while warning the users of the device that is going to be repaired.


Usually, the employer appoints an expert to perform the lockout. They will be in charge of the lockout and for switching the device back on as well as issuing certificates.


Step 1: Disconnect all energy sources


It consists in isolating the work equipment from all possible sources of energy in order to switch off the machine. Most often, it is a matter of switching off the device or stopping the source of fluid flow into the circuits.


  • Electrical lockout: removal of bridges, removal of fuses, removal of plugs from sockets, etc...
  • Fluidic lockout: closing of valves (in this case, a purge or drain is required).
  • Mechanical lockout: uncoupling of mechanisms.


Step 2: Lockout


The lockout means ensuring the safety of the installation. It is the step that makes it impossible to switch the device back on. The locking-out of the equipment must be mechanical and must have a closure that cannot be forced. Each person must affix their own padlock. Lockout equipment such as lockout cables and jaws, valve lockout devices, pneumatic connections, electrical outlets or circuit breakers and lockout padlocks are used. These accessories allow the device to be physically locked-out and thus control the switching off of the equipment.


Step 3: Identification


Identification is the process of locating the facility that has been logged out in order to perform maintenance or repair work on the appropriate equipment, but also to alert others to the operation being performed. A lockout label must be displayed to indicate that the equipment must not be restarted.


Step 4: Checking for Energy Absence


This step verifies that there is no electrical, mechanical or fluid energy in the circuit. Indeed, the danger may come from residual energy.

  • Electrical lockout: use of a dedicated device to check the absence of voltage
  • Fluidic lockout: check the efficiency of the purge
  • Mechanical lockout: visual inspection of the immobilisation


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When all the work on the system has been completed, the machine is then brought back into operation. The steps are generally carried out in the reverse order of the lockout procedure.




In the digital age, it is now time to rely on a digital solution to dematerialize QHSE procedures. An opportunity both to gain efficiency in this process and to improve the monitoring of the state of the system via performance indicators.


No more paper that is filed too quickly or processing via office tools with the well known risks of error. Make way for digitisation! The 5 main components of this process can be digitally "transposed".


Lockout guides and legislation can be integrated from the EDM to facilitate regulatory research and access to standards. All lockout procedures can also be grouped and filtered by site. In addition, lockout permits, electronically signed directly by the employee on the field via their smartphone, will be stored. You will then have an overall view of the current lockouts (validated, in progress, to be processed...) for the different sites.


The same applies to the evaluation of the procedure as well as the inspection of the lockout. Indeed, from an audit frame, you will be able to fill in the questionnaire directly in the field via a tablet or a smartphone. The collected data is automatically fed back into the solution. The idea being "in fine" to generate an audit report enhanced with photos, plans or diagrams directly from the field. 


The global management of the lockout via a digitised tool meets the standards and applicable laws and it gives the HSE culture of the company the necessary stability to offer a safe working environment for employees, support companies in digitising their processes and, why not, move towards industrialisation 4.0.


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