ATEX Pump
EU explosive atmosphere equipment directive, equipment groups, categories, Ex protection types and practical importance in pump selection.
About the Directive
In the European Union, there are two main directives governing explosive atmospheric equipment: 2014/34/EU (ATEX 114), which covers equipment manufacturers, and 1999/92/EC (ATEX 153), the employee health and safety directive for plant operators. 2014/34/EU replaced the previous directive 94/9/EC and is effective from April 20, 2016. This directive establishes a holistic framework for the placing on the market, marking and technical documentation of all types of equipment for use in explosive atmospheres.
The manufacturer obligations under the directive are stringent: the product must be certified by a Notified Body; technical documentation must be prepared; an EU Declaration of Conformity must be issued; CE and Ex marks must be affixed to the product; and the user manual must be prepared in sufficient languages, including the relevant EU languages. The product cannot be placed on the AB market without fulfilling all these obligations.
For engineers and procurement specialists selecting pumps, the practical importance of the directive is as follows: it is not sufficient to look at the ATEX label alone. It is the operator's responsibility to verify that the category, gas group, and T class information on the label correspond to the facility's Zone class, the combustible substance present, and the process temperature. Selecting a pump in the wrong category or gas group will entirely invalidate ATEX compliance.
Directive Details
Group I covers underground mines and related surface structures with methane/coal dust risk; the strictest protection requirements apply for these atmospheres. Group II covers all non-mining industries (petrochemical, chemical, pharmaceutical, food, fuel, etc.). Both groups are subdivided into subcategories, and the applicable Ex protection type may vary on a group basis.
Ex d (flameproof enclosure) prevents the spread of an explosion to the surroundings if one occurs. Ex e (increased safety) eliminates design elements that could create ignition sources. Ex ia (intrinsic safety) keeps circuit energy below the ignition threshold. Ex p (pressurization) pressurizes the interior of the enclosure with clean gas to prevent entry of explosive atmosphere. Ex m (encapsulation) encloses the ignition source within a capsule.
T class defines the maximum temperature that the equipment's external surface can reach. T1 permits the highest surface temperature (450°C), while T6 permits only up to 85°C. A T class must be selected that remains at least %80 below the minimum ignition temperature of the flammable substance in the process environment. Incorrect T class selection creates a serious fire risk under conditions where the motor heats up.
For Category 1 and 2 equipment, approval from a Notified Body is mandatory; these organizations are authorized by the EU and registered in the NANDO database as independent test laboratories. For Category 3 equipment, the manufacturer can conduct its own internal production control and draw up a Declaration of Conformity without applying to a Notified Body. The Declaration of Conformity is the essential document that must be delivered with the pump and archived.
Group II equipment is marked as IIA, IIB or IIC according to gas group. IIA covers gases with low risk such as propane. IIB contains gases with medium risk such as ethylene. IIC corresponds to gases with the lowest ignition energy requirement and therefore the most dangerous, such as hydrogen and acetylene. A pump marked with IIC can also be used in IIA and IIB environments; however, the reverse is not true.
When purchasing a pump, the following steps must be followed in order: confirmation of Zone classification (operator responsibility); determination of the gas group suitable for the existing flammable substance; verification of T class according to process temperature; validation of category-to-Zone match; physical presence of CE+Ex marking; and obtaining the EU Declaration of Conformity. If any of these steps is omitted, the equipment is not considered ATEX compliant.
Equipment Categories
| Category | Environment | Protection Level | Usable Zone | Notified Body |
|---|---|---|---|---|
| 1G | Gas | Very high — two independent protections | Zone 0, 1, 2 | Mandatory |
| 2G | Gas | High — single reliable protection | Zone 1, 2 | Mandatory |
| 3G | Gas | Normal — for abnormal conditions | Zone 2 | Not Required |
| 1D | Dust | Very high — two independent protections | Zone 20, 21, 22 | Mandatory |
| 2D | Dust | High — single reliable protection | Zone 21, 22 | Mandatory |
| 3D | Dust | Normal — for abnormal conditions | Zone 22 | Not Required |
Frequently Asked Questions
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