The Naked Machinery

Last edit: 18/04/2023

When doing a risk assessment of a Machinery, regardless whether you are using ISO 12100 or B11.0, you need to use the concept of the naked machinery.

If you are assessing a machine that is already in operation, you need to see that machine as without any of its safeguards. The machine may have a fixed guard to protect from a dangerous mechanical movement: you need to see the machine without that guard and, for example, ask yourself the question “how often that guard needs to be opened?”. If it is once a day, than that guard is not correct since an interlocked guard needs to be installed.

Without this approach, you would not have assessed the risk of that specific mechanical movement.

That is clearly stated in an informative note:

[B11.0: 2020] 6.3 Identify tasks and hazards

The reasonably foreseeable tasks and associated hazards shall be identified for the applicable phases of the lifecycle of the machine.

Informative Note 3:  The risk assessment process includes identifying hazards regardless of the existence of risk reduction measures.  The machine should not be considered harmless as shipped and guarded.  To verify that all hazards are included, hazard identification should be conducted with all risk reduction measures (including engineering controls and specialized training) conceptually removed.  This is to confirm that hazards are not ignored due to an assumption that the risk reduction measures supplied are adequate for all tasks, including reasonably foreseeable misuse.  Existing risk reduction measures that help achieve acceptable risk can be retained after evaluating their performance.  This decision will be confirmed during the validation/verification portion of the risk assessment (see 6.8).  If a thorough risk assessment is delivered with the machine, it may be used as a starting point for the user’s risk assessment.

In ISO 12100 the following language invites you to use the same approach.

[ISO 12100: 2010] 5.4 Hazard identification

After determination of the limits of the machinery, the essential step in any risk assessment of the machinery is the systematic identification of reasonably foreseeable hazards (permanent hazards and those which can appear unexpectedly), hazardous situations and/or hazardous events during all phases of the machine life cycle, i.e.: […]

Only when hazards have been identified can steps be taken to eliminate them or to reduce risks. To accomplish this hazard identification, it is necessary to identify the operations to be performed by the machinery and the tasks to be performed by persons who interact with it, taking into account the different parts, mechanisms or functions of the machine, the materials to be processed, if any, and the environment in which the machine can be used.

The latest edition of ISO 12100 is dated 2010; that may not seem too long ago. In reality, the text is the same as the 2003 edition! Remember that in 2010 ISO 12100-1, ISO 12100-2 and ISO 14121-1 have been combined in one general standard of “Risk Assessment and Risk Reduction”, without making any significant change in the language of the three standards.

ISO 12100 is therefore about 20 years old and needs a refreshment. The issue is that it is mentioned by so many standards that a new edition would have a significant impact on all of them. The new edition would be needed not to change significantly the approach, but to update the language to new concepts like Whole Body Access, Risk Reduction Measures to be used instead of Protective Measures, Safeguarded space instead of Hazard Zone etc.

A better language that explains the concept of the naked machine would also be welcome.

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