- Overview
- Functional safety
Functional safety
Making safety simple
Are you a machine manufacturer, system integrator or retrofitter? Then you are probably already familiar with the term functional safety. Don’t worry, getting started with functional safety doesn’t have to be complicated - we provide you with a clear and concise guide to functional safety, explaining what it is and how to meet the relevant standards for your machines.
The use of machines and tools offers numerous benefits, such as increased productivity, but also presents certain risks to both users and the environment. Automated moving parts, in particular, can quickly become a hazard. To minimise risks for both users and the environment, it is crucial to adhere to the minimum functional safety standards when developing machines and systems.
A growing trend towards digitalisation and decentralisation can be observed in companies. As a result, requirements are becoming more complex, and configurable and programmable systems for controlling and safeguarding machines and plants are taking on a central role. Standards and directives, when applied correctly, form the basis for a safe and productive system or machine.
Anyone dealing with functional safety will inevitably come across information security at some point. While the terms may seem similar, their scope and requirements are different.
- Learn more about the key differences and aspects of the two terms.
Functional safety
Functional safety focuses on protecting people and the environment.
The primary objective is to prevent physical harm, e.g. due to an accident. To achieve this, the potential hazards posed by a machine must be identified, and safety measures must be implemented to minimise those risks. Measures in functional safety may include emergency stop or emergency off functions, as well as the installation of protective covers.
In a nutshell: Functional safety involves measures that reduce the risks machines pose to people and the environment.
Information security
Information security aims to protect IT and OT systems and information.
The objective is to protect systems and information from data misuse and unauthorised access. Possible and common security measures include data encryption and the implementation of access controls.
In a nutshell: Information security deals with defending machines or systems against external threats, such as hacker attacks.
In Europe, the Machinery Directive (and, in the future, the Machinery Regulation), along with the harmonised European (EN) and international (IEC and ISO) standards, outline the requirements for designing and constructing safe machinery. The topic is also gaining global significance and is governed by national and/or internationalised standards such as IEC and ISO.
Meanwhile, specific safety standards have been developed for various industries and products. Since each application and industry has its own focus, different standards have come into existence, all with the same objective. This range of different standards can be confusing at first.
Upon closer inspection, this ‘mountain of standards’ actually aids safety-related development – but only under one condition: having a compass that helps you navigate them. By applying application-specific standards, machines can be objectively assessed from a legal perspective in the event of damage, providing the manufacturer with clear guidance for action.
| Type A standards | Type B standards | Type C standards |
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The IEC 61508 standard forms the basis of functional safety, outlining fundamental principles and approaches. However, due to its generality, it lacks precision and is not very user-friendly.
The ”safety standards for product groups”, also referred to as “Type B standards”, are more specific and detailed. They summarise commonalities across industries or product groups and provide more specific recommendations for action.
At the same time, specific safety standards exist for many products, known as “Type C standards”. They precisely describe the potential risks a product poses and the measures that need to be taken.
In general, the following applies:
- It is recommended to use the most specific safety standard available.
This approach is not only logical but also helps developers avoid overlooking or misclassifying risks.
Binding specifications (in Europe through the Machinery Directive 2006/42/EC) outline the requirements for the design and construction of safe machinery. These requirements must be met to apply the CE mark.
- Step 1: Check available product standards
Check whether a product standard exists. If a product standard exists that explicitly designates the safety functions, step 2 can be skipped. - Step 2: Risk assessment
All potential risks and hazards a machine may pose must be identified and evaluated using the risk graph. It is important to consider the different operating modes of the machine (e.g. manual set-up or automatic mode). This step also includes categorising the risks into one of the following safety levels:
• ISO 13849-1 (PL a to PL e)
• IEC 62061 (SIL 1 to SIL 3) - Step 3: Safety concept creation
When developing the safety concept, appropriate measures are defined that reduce the risks and hazards posed by the machine to an acceptable level of residual risk. The 3-step method outlined in ISO 12100 is used for this purpose. If one level does not reduce the risk, the next higher level is applied.
- Safe construction of the machine: e.g. protective fence or cover
- Technical measures: select safety components according to safety level (e.g. safety sensors, safety controller, emergency stop)
- Inform users about the remaining residual risk: e.g. with warning labels or signs on the machine
- Step 4: Proof and documentation
In the final step, all measures and results are verified and thoroughly documented in compliance with the requirements of the Machinery Directive. It must be clear that all machine safety requirements and safety specifications are met. After successful verification and documentation, a declaration of conformity is signed and enclosed with each machine.