ATEX Directive inside Equipment

THE DOUBT

Does machinery that contains a potentially explosive atmosphere, but is installed in a non-hazardous area, fall within the scope of the ATEX Product Directive 2014/34/EU?

CONSIDERATIONS

Consider, for example, a mixer that contains a potentially explosive atmosphere during normal operation but is completely enclosed and installed in a non-classified area. During the explosion risk assessment, the manufacturer determines that conditions corresponding to Zone 0 exist inside the mixer. Does this mean that the complete mixer must be considered ATEX Equipment-Group II, with the corresponding conformity assessment procedure and involvement of a Notified Body? In general, no.

However, the reason is not simply that the mixer is installed in a non-hazardous area. Article 1 of Directive 2014/34/EU defines its scope as follows::

[2014/35/EU] Article 1 – Scope
1. This Directive shall apply to the following, hereinafter referred to as “products”:
(a) equipment and protective systems intended for use in potentially explosive atmospheres;

The important concept is therefore the intended relationship between the equipment and the potentially explosive atmosphere, rather than simply the physical location where the equipment is installed. This point is clarified in the ATEX 2014/34/EU Guidelines, 6th Edition, January 2026, §34 Place of intended use. The Guidelines explain that the place of installation — whether the equipment is located in, at or beside a potentially explosive atmosphere — is not in itself decisive. What matters is whether a potential ignition source of the equipment is in contact with, or has an interface with, the potentially explosive atmosphere.

The Guidelines then address precisely the case of machinery containing an explosive atmosphere internally:

[ATEX 2014/34/EU GUIDELINES: 2024] § 34 Place of intended use

[…] It is important to underline in this context how machinery having a potentially explosive atmosphere inside under operating conditions, but having no interface to external potentially explosive atmospheres must to be considered. Such machines, as an integral whole, do not fall under scope of the ATEX Directive 2014/34/EU. 

BUT WHAT ABOUT THE EQUIPMENT INSTALLED INSIDE THE MACHINE? This is an essential distinction. Although the machine, as an integral whole, may be outside the scope of Directive 2014/34/EU, equipment installed inside the potentially explosive atmosphere may itself fall within the scope of ATEX. The 2026 ATEX Guidelines explicitly state that equipment, protective systems and components intended for use in the potentially explosive atmosphere inside the machinery are subject to Directive 2014/34/EU, provided that the relevant ATEX conditions are fulfilled. The Guidelines also clarify that this applies to both electrical and non-electrical equipment used inside machinery containing a potentially explosive atmosphere. Consequently, equipment such as:

• instrumentation;
• electrical motors;
• sensors;
• switches;
• mechanical equipment having its own potential ignition sources;

may need to comply with Directive 2014/34/EU and be assigned the appropriate ATEX Equipment Protection Level (EPL). For example, equipment intended to operate continuously or for long periods in an internal atmosphere corresponding to Zone 0 will normally require the level of protection associated with Equipmet-group 1G (EPL Ga).

THE MACHINERY REGULATION. The fact that the complete machine does not fall under ATEX does not mean that the internal explosion risk can be ignored.

[REGULATION (EU) 2023/1230]  ANNEX III: Essential health and safety requirements relating to the the design and construction of machinery

1.5.7 Explosion. Machinery must be designed and constructed in such a way as to avoid any risk of explosion posed by the machinery itself or by gases, liquids, dust, vapours or other substances produced or used by the machinery […].

In the official Guide to the Machinery Directive the following text is written:

[Guide to 2006/42/EC] §228 Explosion

[…] Although the ATEX Directive is not applicable as such to explosion risks generated within the machinery itself, equipment complying with the requirements of the ATEX Directive must be fitted in areas of machinery where there is a risk of accumulation of a potentially explosive atmosphere.

The Guide to the Machinery Directive consequently explains that, although ATEX does not apply as such to the explosion risk generated within the machinery, ATEX-compliant equipment must be used where appropriate inside areas of the machinery in which a potentially explosive atmosphere may occur. The explosion risk of the machine as a whole is therefore addressed through the machinery legislation, while individual products installed within the internal explosive atmosphere may simultaneously fall under the ATEX Product Directive.

EXPLOSION RISK ASSESSMENT. The machinery manufacturer must therefore carry out an appropriate explosion risk assessment. EN 1127-1 provides an appropriate general methodology for explosion prevention and protection and is specifically referenced by the ATEX Guidelines for this purpose. The assessment should identify:

1. where and under which operating conditions a potentially explosive atmosphere may occur;
2. the possible ignition sources;
3. the required explosion prevention and protection measures;
4. the requirements for equipment installed within the potentially explosive atmosphere.

It is worth noting that, according to the ATEX Guidelines, the machinery manufacturer is not necessarily required to perform a formal zone classification according to Directive 1999/92/EC. The zone concept may nevertheless be used as a practical engineering method for defining the required equipment protection level.

WHAT IF THERE IS AN INTERFACE WITH AN EXTERNAL EXPLOSIVE ATMOSPHERE? The situation changes when the machinery has an interface with an external or process-related potentially explosive atmosphere. The ATEX Guidelines explicitly distinguish between equipment that merely contains an internal explosive atmosphere and equipment that is connected to, or interfaces with, another potentially explosive atmosphere. A good example given by the European Commission is an extraction system installed outside the hazardous area whose fan conveys an explosive atmosphere from a vessel through connecting ductwork. Although the fan may physically be located outside the classified area, its potential ignition source has an interface with the explosive atmosphere. ATEX may therefore apply. This example also demonstrates why saying simply that “equipment installed in a safe area is outside ATEX” would be incorrect.

CONCLUSIONS

The presence of a potentially explosive atmosphere inside machinery does not, by itself, make the complete machinery an ATEX product. If the machinery is installed in a non-hazardous area and the internal potentially explosive atmosphere has no relevant interface with an external or process-related potentially explosive atmosphere, the machine, as an integral whole, normally does not fall within the scope of REGULATION (EU) 2023/1230.

However, equipment installed inside the machine and exposed to that potentially explosive atmosphere must be assessed separately. Where such equipment meets the definition and scope criteria of REGULATION (EU) 2023/1230, it must comply with the applicable ATEX requirements and be appropriately categorised.

The correct principle is therefore: The complete machine does not require ATEX marking merely because it contains an internal potentially explosive atmosphere. However, ATEX requirements may apply to the equipment installed within that atmosphere and to machinery or equipment having an interface with an external or process-related potentially explosive atmosphere.