Realistically, how safe is your system in potentially explosive atmospheres? A spark, leaks, or electrostatic discharges can have serious consequences: from production downtime to endangering people and the environment. Particularly in complex automation systems, the risk increases if components are not coordinated with each other in accordance with standards. Effective explosion protection therefore requires certified, internationally approved solutions – reliable in every zone, for every industry.
Reliable explosion protection is based on three levels:
Together, they ensure safe and efficient system operation.
The IECEx system is the globally recognized basis for the explosion protection of electrical equipment.
It defines uniform testing and certification procedures based on IEC standards, and is used as a reference for national systems in many countries.
What you should know about IECEx:
The ATEX Directive (2014/34/EU) specifies requirements for equipment and protective systems in potentially explosive atmospheres within the EU. It describes how systems, components, and accessories are evaluated and approved with regard to their ignition sources, zone classifications, and equipment categories.
What you should know about ATEX:
The USA and Canada have their own systems for classifying potentially explosive atmospheres: NEC 500 (Class/Division) and NEC 505 (Zone Concept). Certifications are carried out by organizations such as UL (Underwriters Laboratories) and FM (Factory Mutual), which test independently of IECEx.
What you should know about UL / FM:
China has introduced the national CCC Ex system (China Compulsory Certification – Explosion Protection), which replaces the former NEPSI approval. Certification is mandatory for the Chinese market and is based on China's national GB standards derived from IEC standards.
What you should know about CCC Ex / NEPSI:
The Brazilian INMETRO system is based on IECEx, but requires local testing by accredited bodies (OCP). INMETRO certification is mandatory for the operation of electrical devices in Ex zones.
What you should know about INMETRO:
KOSHA (Korea Occupational Safety and Health Agency) certifies appliances for use in potentially explosive atmospheres. The requirements are based on IECEx, but require additional national tests and markings.
What you should know about KOSHA:
In India, the Petroleum and Explosives Safety Organization (PESO) regulates explosion protection for equipment in hazardous atmospheres. Certification is required by law and is based on IECEx standards with additional national requirements.
This is what sets PESO apart:
TIIS (Technology Institution of Industrial Safety) is Japan's national testing system for equipment in potentially explosive atmospheres. TIIS certification is mandatory for market access and ensures that products comply with Japanese safety standards.
What you should know about TIIS:
The ANZEx system is based on IECEx standards, supplemented by country-specific testing and labeling requirements. It is the national certification for the explosion protection of electrical equipment in Australia and New Zealand.
This is what sets ANZEx apart:
In potentially explosive atmospheres, a distinction is made according to the frequency and duration of the occurrence of an explosive atmosphere. Correct zoning is crucial in order to select suitable components and reliably avoid the risk of ignition.
In zone 0, an explosive atmosphere is present permanently or for relatively long periods of time – for example inside tanks, pipelines, or reactors. This zone is therefore particularly critical in terms of safety and requires the highest standards of material, sealing, and temperature resistance. Only specially approved devices and sensors that do not represent a source of ignition even in the event of long-term exposure are allowed to be used here.
Areas in which explosive gases or vapors regularly occur during normal operation are classified as zone 1. This is the case during filling and emptying processes, in gas distribution or mixing systems, or when products are being transferred between reactors and storage tanks. Appliances must be designed in such a way that they do not cause ignition even if they come into frequent contact with explosive atmospheres.
Zone 2 describes areas in which explosive gases, vapors or mists only occur briefly and irregularly – for example, in the event of leaks or in the vicinity of compressors and pipe systems. Devices are adequate providing they work safely under normal operating conditions and do not represent a source of ignition even in the event of faults.
Zone 20 describes areas in which explosive dust atmospheres are permanently or frequently present, for example in silos or filter systems. The same strict requirements apply here as for zone 0 for gases: all devices must be protected against dust deposits, heat development, and electrostatic charging.
In zone 21, an explosive dust atmosphere occurs regularly during normal operation, for example in filling systems, mixers, or in the vicinity of discharge systems. Appliances must be dust-tight and heat-resistant to prevent ignition.
Zone 22 covers areas in which explosive dust atmospheres occur only occasionally – e.g. in packaging, food, or conveyor systems. The components used here are reliably protected against dust and temperature increases under normal operating conditions.
Explosion protection in automation describes all technical and organizational measures that prevent ignition from occurring in systems with potentially explosive atmospheres. This includes the correct selection and certification of electrical and pneumatic components, zone classification, and compliance with international directives such as IECEx or ATEX. This ensures that automated processes run safely, reliably, and in compliance with standards – even in critical environments.
IECEx is an international certification system for devices and components used in potentially explosive atmospheres. It is based on IEC standards and ensures uniform test procedures worldwide.
By harmonizing different national regulations, IECEx facilitates market access and reduces the effort involved in international projects.
ATEX is the European directive for explosion protection (2014/34/EU). It regulates which appliances and protective systems are allowed to be used in potentially explosive atmospheres within the EU. In addition to technical testing in accordance with IEC standards, ATEX also requires legal certificates and CE marking.
Details on the directive can be found under ATEX – European Directive.
IECEx is a global, voluntary certification system, while ATEX is the binding EU directive. Both are based on the same technical standards, but differ in their legal validity: ATEX is mandatory in Europe, IECEx is internationally recognized but optional.
Devices with both certifications can be used worldwide, as the associated test and safety requirements are clearly traceable in accordance with IEC standards.
IECEx certification is carried out by recognized testing bodies that test components in accordance with international explosion protection standards. Manufacturers must prove that their products are not a source of ignition and can be operated safely in the long term. Certified test centers (ExCBs) document the results in a publicly accessible IECEx certificate.
Certification is always required when devices are used in potentially explosive atmospheres, i.e. where gas, vapor, or dust atmospheres can occur. In Europe, ATEX is required by law, while IECEx is used internationally as proof of standard-compliant safety. Certified components not only ensure operation, but also liability and legal compliance.
Explosion protection and functional safety (SIL) both pursue the goal of minimizing risks in automation, but in different ways. Explosion protection prevents explosive atmospheres from igniting. SIL evaluates and reduces systematic or accidental malfunctions in safety-related control systems.
Further information can be found on our page on Functional safety (SIL) in the process industry.
Both areas are part of a holistic security concept. Explosion protection protects systems and people from ignition hazards, while machine safety protects them from mechanical or electrical risks.
Together, they help to assess and minimize risks, and ensure that systems comply with standards.
You can find more detailed information on this on our page Machine safety in automation technology.
ATEX and IECEx describe the explosion protection of electrical devices in hazardous atmospheres, while IP protection types indicate their impermeability to dust and water. Both statements complement each other, but address different safety aspects.