Technical article

Designing machines – assessing risks

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Practical tips for implementing safety measures


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Designers' decisions are crucial for machine safety. This technical article explains the most important legal requirements in the product development process and provides practical advice on implementing safety measures. The important topic of cross-departmental cooperation is also given due consideration.

Note: The technical article has been published under the same title and with minimal changes to the content in the technical journal "Der Konstrukteur" (Edition 04/2025, Special Safety & Security).

Introduction

One of the essential tasks in the safety engineering planning process is the legally compliant performance and documentation of risk assessment. The legally prescribed risk assessment identifies hazards on machines and evaluates risks in order to derive appropriate protective measures. The most important provision here, the EC Machinery Directive 2006/42/EC, defines the procedure for risk assessment. For persons directly involved in the design of machines and systems, the identification of (good) safety solutions, i.e. risk reduction, is particularly relevant. In order to find solutions systematically and efficiently, designers must

  • define the limits of the machine,
  • identify hazards,
  • estimate risks and, based on these parameters
  • ‘evaluate’ whether risk reduction measures are necessary.

The new Machinery Regulation (EU) 2023/1230 also emphasises the importance of comprehensive and early risk assessment. It will be mandatory from 20 January 2027. Risk assessment should already be carried out in the design phase and now takes greater account of new technological developments, in particular the use of artificial intelligence (AI) and aspects of machine security. The Machinery Regulation also requires that software updates and subsequent functional enhancements be taken into account in the risk assessment. This is particularly important for companies that develop machines with digital control systems and adaptive algorithms.
 

Timing of risk assessment

Risk assessments are often performed after a machine or plant has already been designed. Despite being common practice, this approach does not comply with legal requirements: The Machinery Directive stipulates in its general principles that a risk assessment must be performed and that the machine or system may only be designed and built ‘taking into account the results of the risk assessment’.

Section 1.1.2. b) of Annex I of the Machinery Directive (or Annex III of the Machinery Regulation) is particularly important for persons involved in design and construction: The legal acts stipulate that safety measures can be divided into categories and that the order in which measures from different categories are applied is specified by law. It is therefore not in accordance with the Directive, for example, to refer in operating instructions to residual hazards that can also be eliminated by economically feasible design measures.

Similarly, the harmonised European standard EN ISO 12100[1] also requires a three-step approach to risk reduction, as shown in the table. For the procedure during design, this means that risk assessments must be started early in projects. Ideally, this should already be done during the design phase. This ensures that the results of the risk assessment are reflected in the actual designs.

Stage

Machinery Directive 2006/42/EC or
Machinery Regulation (EU) 2023/1230

EN ISO 12100
1Safety integrationInherently safe design measures
2Necessary protective measuresSafeguarding and/or complementary protective measures
3User informationInformation for use

Legal and standard requirements for selecting safety measures

Product note

Safexpert 9.1 - The CE software already supports the new Machinery Regulation (EU) 2023/123030


Since version 9.1, Safexpert has been providing you with targeted support when switching to the new Machinery Regulation (EU) 2023/1230. For machines with a long service life that are placed on the market from 20 January 2027, you can now use the CE guide in accordance with the new Machinery Regulation!

Judgment following serious hand injury

A ruling by the Swiss Federal Administrative Court (ruling C-5864/2009) shows that the three-step concept of risk reduction is not just theory. The case concerned the following facts: A serious hand injury occurred on a circular sawing machine because parts of the machine were still moving after it had been switched off. The machine manufacturer argued that the accident would not have happened if the operator had followed the instructions in the operating manual.

However, the court ruled that the machine did not comply with the requirements of the Machinery Directive. The judgment states: ‘Accordingly, special warnings in the operating manual or instructions for users are only sufficient as a safety measure if other protective measures are not possible or would lead to disproportionate impairment of the machine's usability.’
 

Resolve risks constructively at an early stage and optimise costs

Delayed risk assessments lead to high costs due to modifications and legal risks. The earlier in the project that the topic of safety is addressed in terms of hazards and risks, the greater the influence that can be exerted by the persons carrying out the work, such as designers. For example, certain risks can be eliminated at an early stage through design, ideally without additional costs. Hazards that are only identified at a later stage must either be safeguarded by potentially expensive safeguards (e.g. light curtains) (in which case it must be checked whether the three-step principle is still being observed) or by design modifications – which is reflected in personnel costs.

Risk assessment is carried out before the construction of machines or plants

 

Risk reduction measures

a) Inherently safe design (level 1)

What must designers now do to build safe machines and systems in accordance with the three-step concept? According to EN ISO 12100 Section 6.2, designers should already avoid hazards during the design phase. This includes, among other things, avoiding pinch points and shearing points, limiting forces and emissions, and ensuring ergonomic design, selecting suitable technologies and ease of maintenance.
 

b) Support from standards

Technical standards help with implementation. So-called type-C standards (product-specific standards) provide support, for example, by offering specific solutions or referring to general safety standards (B standards) for maximum forces, surface temperatures, distances, etc. When selecting standards, the following two questions in particular must be considered:

  • Is the standard suitable for the intended use (e.g. if children can also enter the danger zone of the machine)?
  • Is it valid at the time of placing on the market, e.g. when the machine is sold?

The CE software Safexpert from IBF Solutions (see info box) supports numerous functions related to risk assessment and CE documentation, particularly when it comes to monitoring the status of standards at the level of individual safety measures.
 

c) Safeguarding and/or complementary protective measures (level 2)

If hazards cannot be eliminated or safeguarded by inherently safe designs, technical protective measures are used. Examples of this are

  • Protective devices such as protective fences or flaps
  • Control-monitored protective devices with interlocking
  • Guard lockings for follow-up hazards

For the above-mentioned ruling on the circular sawing machine, a locked protective device with guard locking would have been a possible solution, which would probably have prevented the accident and thus also a guilty verdict. In addition to separating protective devices, non-separating protective devices such as contact-free protective devices or two-hand controls are examples of level 2 measures.

The interaction between mechanical designs (e.g. safety doors) and control monitoring creates an important interface between different disciplines: depending on the risk assessment, requirements for the safety function arise. These define the reliability of the effect chain from the sensor to the actuator. These requirements, which are determined in the risk assessment, are made available to control engineers, for example, as ‘required performance levels’ (PLr) for the design of the safety function (e.g. in accordance with EN ISO 13849-1). As supplementary protective measures, ISO 12100 mentions, for example, emergency stop devices, which may have to be additionally installed on machines.
 

d) Risk reduction through information for use (level 3)

Information for use serve to increase the recognisability of unavoidable hazards. The risk assessment determines which information channel is used. Communication with users can take place via various channels, such as

  • directly on the machine, for example in the form of pictograms
  • in the operating instructions
  • on the packaging

There is a central interface between design and technical editing: residual hazards documented at an early stage can be elaborated later in the operating instructions. This saves research time and ensures completeness. Visual and acoustic signals can also be used – although EN ISO 12100 warns against sensory overload.

New requirements for operating instructions

A significant difference in the new Machinery Regulation is the option to provide operating instructions in digital form. This can offer significant advantages in terms of updating and providing relevant safety information. However, the following must be ensured:

  • Easy access to the digital operating instructions throughout the entire service life of the machine
  • A printed version must be available upon request by the user
  • Safety-critical information must continue to be affixed to the machine itself in physical form
     

Conclusion

Many individuals contribute to ensuring that machines and systems meet safety requirements. Design engineers play a very important role in this regard. Risk assessments are used to identify at an early stage the hazards and risks posed by the machine or system to be developed.

By performing the legally required risk assessment process at an early stage, and in particular the three-step concept of solution selection, machines and systems are created with a high level of safety – with the added benefit of saving the expense of extensive redesigns or the cost of expensive safety equipment.


Posted on: 2025-06-23

Authors

Daniel Magnus, BSc
Head of Marketing at IBF. Degree in Business Sciences from the SoWi Innsbruck. Over 10 years of experience in the B2B sector, with a focus on mechanical and automotive engineering, electronics development/production and software development.

E-mail: daniel.magnus@ibf-solutions.com | www.ibf-solutions.com

 

Johannes Windeler-Frick, MSc ETH
Member of the IBF management board. Specialist in CE marking and Safexpert. Presentations, podcasts and publications on various CE topics, in particular CE organisation and efficient CE management. Management of the further development of the Safexpert software system. Degree in electrical engineering from ETH Zurich (MSc) with a focus on energy technology and specialisation in the field of machine tools.

Email: johannes.windeler-frick@ibf-solutions.com | www.ibf-solutions.com

 


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