In the context of machine safety, risk assessment is a key process to ensure the safety of users throughout the lifecycle of a machine.
EN ISO 12100:2010 defines principles and methods during the machine design process that enable designers to identify hazards and assess their risks. The aim of the standard is to produce machines that are safe when used as intended.
When should a risk assessment of a machine be carried out?
A risk assessment should be carried out at every stage of the machine’s life cycle. Even at the design stage, potential hazards should be anticipated and appropriate safeguards put in place.
During transport and installation, there are also hazards associated with the movement of heavy components and their proper assembly. The operating phase is when the machine is most heavily loaded, increasing the likelihood of failures and hazardous events. Another important phase is maintenance and servicing, where service work is required, often with direct interaction with the machine.
Retrofitting risks also need to be considered – a change in machine function or expansion can introduce new hazards. Dismantling, especially of large and complex machines, requires special attention to minimise risks to workers and the environment.
Responsibility for assessing the risks of a machine lies with both the designer and the user of the machine. The designer is responsible for identifying hazards and designing safe solutions, while the user should monitor the condition of the machine and follow operating instructions and maintenance recommendations.
Responsibility for assessing the risks of a machine lies with both the designer and the user of the machine. The designer is responsible for identifying hazards and designing safe solutions, while the user should monitor the condition of the machine and follow operating instructions and maintenance recommendations.
How is a machine risk assessment carried out?
The machine risk assessment process includes risk analysis, risk estimation and risk evaluation. The first step is risk analysis, which involves identifying the hazards associated with the machine and the constraints that may affect its safety. This stage takes into account, among other things, the characteristics of the machine, the way it is used and environmental factors such as working conditions or user interactions.
This is followed by a risk assessment, in which the severity of the harm and the likelihood of it occurring are assessed. At this stage, it is determined to what extent people are exposed to hazards and what the chances are of avoiding or reducing the effects of hazardous events.
An important part of risk assessment is the selection of appropriate risk analysis methods. One of the most popular methods is the risk matrix, which allows risks to be visualised by determining their probability and impact.
Risks are ranked according to their severity, making it easier to prioritise actions to minimise risk. A second method is the risk graph, which allows the hierarchy of risks to be assessed and the effectiveness of risk mitigation measures to be estimated.
Risk analysis and estimation is followed by risk assessment, which determines whether the measures taken are sufficient or whether additional measures are needed to further reduce the risk.
Reducing risks associated with machine operation
The risk reduction process uses a hierarchy of measures, starting with the most effective. The first step is to design solutions that are safe in themselves, eliminating hazards at the machine design stage. Examples of such solutions include removing sharp edges or reducing the speed of moving parts.
Where it is not possible to eliminate hazards by design, engineering controls such as guards, interlocks or warning systems are used. These are an effective way of restricting access to hazardous areas or minimising the effects of potential hazards.
The final step in the hierarchy is user information, which includes operating instructions, signage and warning pictograms. The purpose of this information is to inform users of potential hazards and how to avoid them.
The whole process of reducing the risks of a machine is iterative – that is, once safeguards have been put in place, the situation must be reviewed to ensure that the risks have been sufficiently reduced.
Documenting the assessment and reduction of risks from machinery
EN ISO 12100 requires that the whole risk assessment process and the risk reduction measures taken are properly documented. The documentation should include a detailed description of the hazards, the risk assessment and the safeguards applied. Such a record allows the history of machine modifications to be traced and ensures compliance with legal requirements and safety standards.
Conclusion
Risk assessment of machinery based on EN ISO 12100 is an essential part of the process of designing and operating machinery.
By carrying out a systematic risk analysis, hazards can be identified and appropriate protective measures can be implemented to minimise the risk of accidents.
In this way, both designers and users can be confident that machinery will be safe throughout its lifetime.
