Machinery risk assessment under ISO 12100

ISO 12100 establishes principles and a methodology for assessing and reducing risks in machinery design. Its approach connects hazard identification, risk estimation and evaluation, and risk reduction decisions across the relevant phases of the life cycle.

In brief

ISO 12100 provides a framework for reasoning about machinery safety. Assessment must explain the hazardous situations, the measures selected and how risk reduction is verified. It cannot be reduced to a score and does not replace applicable specific standards and legal requirements.

Contents
  1. What the standard is for
  2. Considering the life cycle and tasks
  3. Identification, estimation and evaluation
  4. Linking measures and checks
  5. Specific standards, editions and compliance
  6. Hypothetical example: cleaning a feed area
  7. Related concepts
  8. References

A–Z dictionary →

What the standard is for

The standard aims to achieve safety in machinery design. It incorporates experience of design, use, incidents and accidents, and provides guidance on documenting and verifying the risk assessment and reduction process.

It is a different reference from a general job risk assessment. Machinery safety requires knowledge of the equipment’s hazards, while the job may add exposures and organisational conditions requiring other approaches.

Considering the life cycle and tasks

The analysis must consider the relevant phases of the equipment’s life. Observing normal production alone is not enough: assembly, adjustments, cleaning, troubleshooting or maintenance may involve different access requirements and situations.

A useful way to prepare the assessment is to describe who is involved, what they do, where they may come into contact with a hazard and under what conditions. A generic hazard list loses value if it is not linked to specific situations involving the machine.

Identification, estimation and evaluation

Identifying a hazard, estimating the risk and evaluating the need for reduction are related but different tasks. The assessment must make the reasoning from a hazardous situation to a decision explicit.

The absence of known accidents does not eliminate a hazard. A matrix without an explanation of its assumptions is also insufficient. Experience of use, failures and incidents helps check whether the analysis represents foreseeable conditions and the interventions actually carried out.

Linking measures and checks

Risk reduction must address the identified hazard. Installing a guard requires checking that it protects the necessary area and that its use is compatible with the intended tasks. Measures may also change how the equipment is cleaned, adjusted or maintained.

After a modification, the whole system must be reviewed to identify risks introduced or transferred elsewhere. Documentation must make it possible to understand what has changed and the evidence supporting the adequacy of the reduction achieved.

Specific standards, editions and compliance

ISO 12100 is a type-A standard used alongside type-B and type-C safety standards. ISO/TR 22100-1 explains this relationship for designers and manufacturers. References must be selected according to the machine, function and scope.

Before applying a standard, check the published edition and its status. A draft revision is not equivalent to an approved standard. Applying this framework does not automatically establish that all CE marking requirements have been met.

Hypothetical example: cleaning a feed area

On a machine, routine work takes place with the area guarded, but cleaning requires a different intervention. The technical team identifies this situation, reviews the hazard and defines a solution that allows the task to be performed with reduced risk.

The solution is verified and documented together with the necessary instructions. The analysis does not simply conclude that the machine is protected during production, because that observation does not represent the cleaning intervention.

References

  1. ISO. ISO 12100:2010, scope and publication status. Official source
  2. ISO. ISO/TR 22100-1:2021, relationship with type-B and type-C standards. Official source

Editorial information

Publication date: 19 October 2026.

Editorial responsibility: Sabentis Editorial Team.

Author: Pablo RodríguezLinkedIn

Executive Vice President of the ORP International Foundation and Chief Financial Officer of Sabentis.

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