30 n INDUSTRIAL SECURITY July/August 2026 www.drivesncontrols.com Zones and conduits: how security protects safety Standards such as IEC 62443-3-2 and the forthcoming EN 50742 set out a clear direction: separating industrial systems into zones, and monitoring connections – a principle that runs through current recommendations from industry bodies and experts. The strict separation of safety and so-called standard automation is the key to effective machinery safety – underpinned by the defence-in-depth principle, and is implemented through an approach known as “zones and conduits”. To make an analogy: a house can be built to be sturdy and safe, with solid walls, fireresistant materials, reliable electrics and working alarms. Similar structural safety is a key to machinery safety, where design measures, sensor technologies and protective mechanisms prevent unintended hazards. However, a house only remains safe as long as it is not subjected to deliberate interference. Manipulating its heating controls, sabotaging its electrical circuits or deactivating its alarm systems can transform a building designed with safety in mind, into a hazard. In the world of machinery, the best safety-related design becomes ineffective if safety-related components are tampered with, or disabled without authorisation. In this context, security plays an external protection role. Sturdy doors, secure access points, monitored connections and barriers can prevent unauthorised interventions. Security does not protect against accidents, but instead stops protective mechanisms from being disabled – by individuals who gain access via an unauthorised operating mode selection or actions, for example. Security for safety For the first time, the Machinery Regulation (EU) 2023/1230 makes security a mandatory requirement for functioning safety on plant and machinery. Safety functions must not be compromised due to manipulation, whether intentional or otherwise. This is where the emerging EN 50742 standard comes in. It will help to clarify the essential security requirements of the Machinery Regulation. The standard defines technical details for protection against corruption, and sets out clear requirements for hardware, software and data that may affect safety-related functions. The standard covers the entire lifecycle, from development through to operation and decommissioning. The existing IEC 62443 series of standards, which set out a systematic approach to cybersecurity for industrial automation and control systems (see table, right), also play a key role. They provide a structured framework for risk analysis, “defence-in-depth” and the principle of segmentation – the zones and conduits, mentioned previously. They are explicitly recognised in EN 50742 as an alternative or complementary approach to safeguarding security. The range of topics covered in IEC 62443 runs from risk analysis, to requirements for secure operation and the secure development of products (security by design). It currently offers the best orientation guide for plant operators, machine-builders and device manufacturers when it comes to implementing industrial security effectively. The standard covers five areas: foundational industrial security requirements; the principle of zones and conduits; security levels; the security lifecycle; and risk analysis. Together, IEC 62443 and EN 50742 form the normative core of security for safety. They require the digital integrity of a machine to be recognised as a prerequisite for its functional safety, and protected accordingly. Zones and conduits make machinery safer Returning to the analogy of the house. The boiler room represents a zone, while the connection to the smart home gateway represents the associated conduit. If this connection is manipulated, the entire system can be affected – even if the room is perfectly secure. Therefore, it is not only crucial to safeguard the individual zones, but also the security of the routes that connect them. This is precisely where the zones and conduits principle comes into play. Zones are clearly separated from one another, and the transitions between them are designed to be monitored. Just as in a house, where doors and assigned keys determine who can go where, internal protection (safety) and external protection from manipulation (security) are intertwined in an industrial plant. The result is a protection concept based Industrial security is designed to protect safety-related functions from manipulation. Security is a prerequisite for functioning safety, and is mandatory in the EU’s Machinery Regulation which comes into force next January. But how do you provide holistic protection for an automation network? Andreas Willert, head of industrial security at Pilz Austria, explains. Zones and conduits: separating safety-related control systems into a separate zone with increased security
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