While setting or maintenance work of the equipment, it is necessary to disconnect energy from the machine or device. In order to avoid unauthorized or accidental resumption of the device by unauthorized persons and protect employees from the consequences of dangerous situations, for the whole period of service, the system of LOTO blockades and markings is becoming more and more common.

LOTO from English Lock-Out/Tag-Out.
Lock out – block, Tag out – mark.

LOTO system guarantees lack of physical access to the elements that enable the device to be re-commissioned through sets of legible marking of these blocks and strategic elements of the security system.

LOTO secures in case of following dangers:

  1. electrical
  2. mechanical
  3. chemical

It implements the recommendations of the Machinery Directive 2006/42/EC regarding the disconnection of equipment from energy sources in the scope of maintenance (item 1.6.1, Annex I). The directive says that it is necessary to equip the machine with clearly marked devices that disconnect it from all energy sources. These devices should be able to be blocked primarily when the operator is unable to check the disconnection of the machine from the source of energy from any space available to him.

Lock-Out corresponds to the use of mechanical protections eg. in the form of a padlock, preventing the machine from restarting until the security is removed by an authorized person. It protects the maintenance staff during work on the machine.

Tag-Out (Tag) is a system of warning and information tags (eg posters and appropriate training of employees) about the temporary shutdown of a given machine from operation.

Only the person who performs work and assumes security is authorized to take pictures of them. This is a guarantee that it will not be adversely affected by unauthorized persons.

The LOTO system applies:

  1. Pendant – warns that a particular machine or device is just locked and cannot be turned on until the pendant is removed.
  2. Padlocks – used for door locks or directly on devices, are a simple and safe way to lock. They can be made of various materials, simple identification, which padlock color corresponds to the employee.
  3. Interlocks – they are used to block various types of valves, handles or levers. Some locks have a regulation function, which makes them widely applicable.


The Regulation of the Minister of Economy of March 28, 2013 on health and safety at work on energy devices imposes on the employer an obligation to implement appropriate work safety systems at the workplace. This is especially important when it is not possible to cut off energy in the danger zone, eg. in the case of machine adjustment.

Nevertheless, the reports of the National Labor Inspectorate show that in 24% of companies1 there is no detailed analysis of their causes or it is made with unjustified delay.

It is also worrying that more than in every third workplace, the causes of accidents are not determined at all (in 2014, over 38% of companies2 covered by the PIP study did not determine all the causes of accidents).

Statistic data proves that in the ​​machine safety area, including LOTO system, there is still a lot to do in many companies.

1,2 Source: PIP data, 2014