CE Marking Risk Assessment for Machinery: ISO 12100 Requirements Explained

For machinery manufacturers, ISO 12100 provides a structured way to turn hazard knowledge into design decisions. This article focuses specifically on that methodology: defining machine limits, identifying hazardous situations, estimating and evaluating risk, selecting risk-reduction measures and documenting residual risk.

The aim is not to repeat the complete CE marking process. Instead, this is the specialist risk-assessment guide within the wider machinery compliance content cluster.

For the end-to-end conformity route covering classification, legislation, standards, verification, documentation and final marking, use the CE Marking for Machinery compliance checklist.

Why Risk Assessment Matters for Machinery CE Marking

Under the Machinery Directive 2006/42/EC, manufacturers must address the essential health and safety requirements relevant to their machinery and maintain technical documentation showing the measures taken to deal with associated risks.

A properly structured assessment helps the manufacturer answer several essential questions: What can cause harm? Who could be exposed? Under what circumstances can the hazardous event occur? How serious could the harm be? What design or protective measures can reduce the risk? What residual risk remains after those measures are applied?

These questions matter throughout the machine lifecycle—not only during normal production. Installation, setup, cleaning, adjustment, fault finding, maintenance, foreseeable misuse and decommissioning can expose people to hazards that are absent during routine operation.

What Is ISO 12100?

ISO 12100 is a fundamental machinery-safety standard covering general principles for design, risk assessment and risk reduction. It provides a systematic framework that manufacturers and designers can use to identify hazards, estimate and evaluate risks and select appropriate risk-reduction measures.

The site's dedicated machinery risk assessment page describes BS EN ISO 12100:2010 as a framework for identifying and eliminating hazards across different stages of a machine's lifecycle.

ISO 12100 does not replace the need to understand the legislation or machine-specific standards. Instead, it provides a general methodology that can be combined with relevant Type B safety standards and Type C standards for particular machine categories.

Step 1: Define the Limits of the Machinery

Before identifying hazards, define what is being assessed. The limits of the machinery establish the boundaries of the risk assessment.

Manufacturers should consider the machine's intended use, reasonably foreseeable misuse, operating modes, users, physical limits, environmental conditions and lifecycle stages. This can include:

·        Transport and handling

·        Assembly and installation

·        Commissioning and setup

·        Normal operation

·        Adjustment and changeover

·        Cleaning

·        Fault finding and intervention

·        Preventive and corrective maintenance

·        Dismantling and decommissioning

The assessment should also consider different users. Operators, maintenance engineers, cleaners, installers and bystanders may encounter different hazards and may have different levels of training or access.

Step 2: Identify Machinery Hazards

Hazard identification should be systematic. The goal is to identify sources or situations with the potential to cause harm rather than focusing only on hazards that have already resulted in incidents.

Depending on the machine, relevant hazard categories can include:

·        Mechanical hazards such as crushing, shearing, cutting, drawing-in, entanglement and impact.

·        Electrical hazards including direct or indirect contact and stored electrical energy.

·        Thermal hazards from hot or cold surfaces, materials or processes.

·        Noise and vibration.

·        Radiation or emissions where relevant.

·        Hazards from materials and substances used or generated by the process.

·        Ergonomic hazards and unsuitable human-machine interaction.

·        Unexpected start-up, control-system faults or loss of energy.

·        Slipping, tripping, falling or access hazards.

·        Hazards during lifting, handling, maintenance or stored-energy release.

Hazards should be considered in relation to tasks and operating conditions. The same moving part may present one risk during automatic production and a very different risk when a guard is open for cleaning or maintenance.

Step 3: Estimate the Risk

Once a hazardous situation has been identified, the manufacturer estimates the associated risk. Risk estimation typically considers the severity of possible harm and the probability of that harm occurring.

Probability is not simply a guess at how often an accident might happen. Factors such as exposure frequency, duration of exposure, the possibility of avoiding or limiting harm and the likelihood of a hazardous event can all influence the assessment.

The method used should be suitable for the machinery and applied consistently. Some organisations use a risk matrix, while others use structured scoring systems or machine-specific methodologies. The scoring tool is less important than the quality and traceability of the reasoning behind the result.

Step 4: Evaluate Whether Risk Reduction Is Required

Risk evaluation determines whether the existing level of risk is acceptable or whether further reduction is required. This stage should consider the effectiveness of existing design features and safeguards rather than assuming that the presence of a guard or warning automatically resolves the hazard.

Where the risk remains unacceptable, additional measures should be identified and implemented. The machine should then be reassessed to determine whether the measures reduced the risk as intended and whether they introduced new hazards.

Step 5: Apply the Three-Step Risk-Reduction Method

ISO 12100 establishes an important hierarchy for machinery risk reduction. Manufacturers should work through the measures in the appropriate order rather than relying immediately on warnings or personal protective equipment.

1. Inherently Safe Design Measures

The preferred approach is to eliminate hazards or reduce risk through the design itself. Examples can include reducing accessible forces, increasing clearances, eliminating sharp edges, selecting safer technologies, limiting speed or energy, improving stability or designing access so that people do not need to enter hazardous areas.

Designing out a hazard is generally more reliable than expecting an operator to manage it through behaviour.

2. Safeguarding and Complementary Protective Measures

Where risk cannot be adequately reduced by inherently safe design, safeguarding and other protective measures are considered. Depending on the machinery, this can include fixed guards, movable interlocked guards, protective devices, emergency-stop functions, safe control functions, isolation systems and measures for safe access.

Safeguards should themselves be assessed. A guard that can be easily defeated, creates a new trapping point or prevents necessary maintenance may not provide the intended level of protection.

3. Information for Use

Residual risks that remain after design and safeguarding measures should be communicated through appropriate information for use. This can include warnings, markings, instructions, training requirements and information about personal protective equipment where relevant.

Warnings should not be used to compensate for hazards that can reasonably be eliminated or reduced through engineering measures.

Risk Assessment and the Machinery Technical File

Once the assessment is complete, its role in the technical file is to provide traceable evidence of the hazard-analysis and risk-reduction decisions. The risk record should identify the machine version assessed and connect significant controls to the relevant design or validation evidence.

A useful risk-assessment record can include:

·        Machine description and scope of assessment

·        Intended use and foreseeable misuse

·        Lifecycle phases and tasks assessed

·        Hazards and hazardous situations identified

·        Persons potentially exposed

·        Initial risk estimation

·        Existing and proposed control measures

·        Standards or technical requirements used

·        Residual risk after controls

·        Actions, responsibilities and completion status

·        References to drawings, tests or validation evidence

·        Revision history and approval information

This section deliberately covers only the risk-assessment record. For the full document architecture, revision control, drawings, testing, instructions and declaration evidence, see CE Marking Technical File: What Manufacturers Need to Include in Technical Documentation.

Risk Assessment and Machinery Instructions

One of the final outputs of risk assessment is a clear record of residual risks that remain after inherently safe design and safeguarding have been applied. Those residual risks should feed into the information supplied to users where appropriate.

The important SEO and compliance distinction is that instructions are not themselves the risk-control strategy. They communicate the remaining conditions for safe use after higher-priority engineering measures have been considered.

Risk Assessment for Modified Machinery

Modifications deserve particular attention. The site's Machinery Directive guidance notes that substantial modifications—such as unanticipated changes in function or performance—can affect the validity of the original CE marking.

When machinery is modified, the risk assessment should be reviewed to determine whether new hazards have been introduced, existing risks have changed, safety functions remain adequate and the original compliance evidence still reflects the machine.

This is especially important when changes involve controls, automation, guarding, speed, capacity, tooling, software or integration with other equipment.

Risk Assessment for Assemblies of Machinery

Integrated production systems require an interface-level assessment in addition to the assessments for individual machines. Transfer points, shared safety functions, access between units, control interactions, restart behaviour and emergency-stop zoning can create hazards that are not visible when each machine is reviewed in isolation.

The responsible integrator should therefore document hazards created by the combination and validate the measures used at those interfaces. This interface-risk focus is different from simply collecting the CE documentation supplied with each individual machine.

Common Machinery Risk Assessment Mistakes

Defining the machine limits too narrowly: If the assessment ignores setup, cleaning, maintenance, abnormal conditions or foreseeable misuse, important hazardous situations can disappear from the analysis before risk estimation even begins.

Recording hazards without describing hazardous situations: A useful assessment explains how a person becomes exposed, during which task or operating mode, and what event could lead to harm.

Using risk scores without documenting the reasoning: A number in a matrix is not enough. Record the assumptions behind severity, exposure, occurrence and avoidance so later reviewers can understand the decision.

Selecting controls before considering inherently safe design: The ISO 12100 hierarchy starts with design measures. Jumping immediately to guards, warnings or PPE can leave opportunities for more reliable risk reduction unexplored.

Failing to evaluate risk after the control is implemented: Residual risk should be reassessed after the proposed measure is in place, including whether the measure introduces a new hazard or changes another task.

Treating every operating mode as equivalent: Manual setup, automatic production, teach mode, cleaning and maintenance can have different exposure conditions and therefore require separate consideration.

Closing actions without validation evidence: Where a risk-control measure depends on a safety function, guard, interlock or other protective measure, the assessment should point to evidence that the measure was implemented and performs as intended.

Practical ISO 12100 Machinery Risk Assessment Checklist

☐ Define the machine and assessment boundaries.

☐ Document intended use and reasonably foreseeable misuse.

☐ Identify relevant users and exposed persons.

☐ Review every relevant lifecycle phase.

☐ Identify mechanical, electrical, thermal and other hazards.

☐ Identify hazardous situations and foreseeable events.

☐ Estimate the initial risk for each hazard.

☐ Evaluate whether further risk reduction is required.

☐ Apply inherently safe design measures first.

☐ Add safeguarding and complementary protective measures where necessary.

☐ Define information for use for remaining residual risks.

☐ Reassess risk after controls are implemented.

☐ Verify that controls do not introduce new hazards.

☐ Reference relevant standards and technical evidence.

☐ Record residual risks in the appropriate instructions.

☐ Include the assessment in the technical documentation.

☐ Review the assessment after design changes or machinery modifications.

Preparing for Machinery Regulation (EU) 2023/1230

Manufacturers should also plan for Machinery Regulation (EU) 2023/1230, which applies from 20 January 2027 and replaces the current Machinery Directive framework.

The new Regulation continues the risk-based approach to machinery safety while updating the framework for modern machinery and emerging technologies. Manufacturers developing products with long design cycles should ensure that risk assessments, technical documentation and conformity processes are prepared for the legislation that will apply when the machinery reaches the market.

When Professional Machinery Risk Assessment Support Is Useful

Specialist support is most useful when the assessment requires multidisciplinary judgement—for example, complex guarding, safety-related control systems, unusual operating modes, integrated lines, significant modifications or uncertainty about the standards that inform risk reduction.

An independent reviewer can also challenge assumptions in the hazard analysis, check whether lifecycle tasks were missed and verify that proposed controls follow a defensible risk-reduction hierarchy.

CE Marking Authority provides support with machinery risk assessments. For a specific machine or integrated system, contact CE Marking Authority to discuss the assessment scope.

Frequently Asked Questions

Is a risk assessment required for machinery CE marking?

Risk assessment is a core element of machinery conformity. The manufacturer needs to determine the applicable safety requirements, identify hazards and document the measures used to reduce risk.

What is ISO 12100 used for?

ISO 12100 provides general principles for machinery design, risk assessment and risk reduction. It gives manufacturers a structured methodology for identifying hazards, evaluating risks and selecting protective measures.

When should machinery risk assessment begin?

Ideally, it begins during the design stage. Early assessment allows hazards to be designed out before changes become expensive or difficult to implement.

Does a risk assessment need to cover maintenance?

Yes. Relevant lifecycle stages and tasks should be considered, including installation, operation, cleaning, adjustment, fault finding, maintenance and decommissioning where applicable.

Can warning labels make a machine safe?

Warnings are part of information for use and can address residual risks, but they should not replace inherently safe design or safeguarding where those measures can reasonably reduce the risk.

Should the risk assessment be updated after a machinery modification?

Yes, where a modification can affect hazards, safeguards, controls, intended use or the original conformity basis. The assessment and supporting technical documentation should continue to reflect the actual machine.

Conclusion

A strong ISO 12100 risk assessment is a traceable engineering argument: it defines the machine boundaries, identifies how people can encounter hazards, estimates the associated risk, applies the hierarchy of risk reduction and records what residual risk remains.

This article is intentionally the specialist methodology resource in the four-blog cluster. For the wider conformity sequence, use the CE Marking for Machinery checklist; for evidence organisation and document control, use the CE marking technical-file guide; and for the final manufacturer declaration, use the EU Declaration of Conformity guide.

For manufacturers that need help developing or independently reviewing a machine-specific risk assessment, CE Marking Authority can provide project-specific support.