This brief guide aims to explain what ATEX Certification is and its meaning when present in some fluid handling and management products.
Two European Directives regulate ATEX Certification:
- The “Workplace” Directive 1999/92/CE (RD 681/2003). Commonly known as ATEX 137, refers to minimum requirements for improving the health and safety protection of workers, under the responsibility of the facility’s owner.
- The “Equipment” Directive 2014/34 / EU (RD 144/2016). Commonly known as ATEX95 (formerly ATEX100), establishes the safety requirements for equipment and systems and the responsibility lies with the manufacturer. SAMOA Industrial manufactures ATEX certified products to transfer all types of fluids.
As our product is fundamentally pneumatic, particularly UNE-EN ISO 80079-36, referring to non-electrical equipment intended for explosive atmospheres, also applies.
What is EXplosive ATmosphere (ATEX)
An explosive atmosphere refers to a work area where there could be a risk of explosion. An explosion takes place when an oxidizer (usually oxygen from the air), a fuel ( vapor, liquid or dust) and an ignition source (a spark, a flame or a high temperature surface) come together.
Not all equipment can be operated in environments defined as ATEX. To this end, they must contain the ATEX marking on their labels and manuals. Our ATEX certified products can work with flammable fluids ( -oil, Dieseldiesel, chemicals in general, etc.) – in the presence of air. Under such circumstances, any source of uncontrolled ignition can create an explosion. The ignition source may be generated by an electrostatic discharge, if the equipment is not well insulated or part of it is kept at high temperature through sustained friction of some of its components.
Any equipment at risk of explosion in an area certified as ATEX must be labeled with the appropriate ATEX reference for each zone.
The ATEX equipment category definition will be interpreted based upon the environment for which it is intended. There are two different environment groups:
- GROUP I. Mines susceptible to firedamp
- GROUP II. For explosive atmospheres, other than mines or their surface installations.
According to UNE-EN ISO 80079-36, the definition of the ATEX Equipment category is defined depending on the environment intended.
- GROUP I. Mines susceptible to firedamp
- GROUP II. Rest of Surface Installations with explosive gas atmosphere.
- GROUP III. Rest of Surface Installations with explosive dust atmosphere.
It is important to differentiate between these classifications as they both appear in the team designation, but they refer to different concepts. Directive 2014/34 / EU focuses on the general classification of the different atmospheres in which equipment can operate, and UNE-EN ISO 80079-36 focuses on the designation of the particular equipment devised to be operated at the facilities defined at the Directive.
Types of Atmospheres
As it happens with Groups, the type of Atmospheres are differentiated by the directive and specific standards applications, in our case, UNE-EN ISO 80079-36.
The Directive shows, that depending on the most likely product type to generate an explosive atmosphere, there are two types of atmosphere to consider:
- Atmosphere G (Gas)
- Atmosphere D (Dust)
The specific equipment regulations indicate that depending on the type of product likely to generate the explosive atmosphere, there are different types of atmosphere to consider for the equipment designation:
- GROUP I, the atmosphere is formed by firedamp gas and a significant proportion of other flammable gases or combustible dusts is considered.
- GROUP II, the explosive gas atmosphere is considered different from mines with risk of firedamp. There These are the following subdivisions:
- IIA, typically propane.
- GROUP III, the explosive dust atmosphere is considered different from mines with firedamp risk. These are the following subdivisions:
- IIIA, suitable for combustible suspended particles.
Zones and their risks
Within ATEX installations, according to the Directive, different zones are defined according to the explosion danger and fluid generating it.
The definition of zones for gas / liquid atmospheres are as follows:
- ZONE 0 – PERMANENT DANGER. Location where an explosive atmosphere is present permanently or for long periods.
- ZONE 1 – POTENTIAL HAZARD. A location where an explosive atmosphere is liable to form under normal circumstances.
- ZONE 2 – MINIMUM DANGER. A location where an explosive atmosphere is not likely to form in normal operation and where such formation, if it occurs, can only exist for a short period of time.
The definition of zones for dust atmospheres are as follows:
- ZONE 20 – PERMANENT DANGER
- ZONE 21 – POTENTIAL HAZARD
- ZONE 22 – MINIMUM DANGER
Examples of ATEX zones in different installations
Example 1. Operation loading and unloading of flammable fluids
Example 2. Loading and unloading operation at Gas Stations and Service Stations
The following table shows the equipment characteristics according to its category.
|i - MINES||M1 - Very High protection level|
|M2 - High protection level|
|II - SURFACE INDUSTRIES||1.- Very High Protection Level. If one protection mode fails, there is another that replaces it.|
|2.- High Protection Level|
|3.- Normal Protection Level|
In accordance with specific regulations, the equipment category is defined according to the protection level required by the equipment to be installed at explosive atmospheres. The following table shows the equipment characteristics in line with its category, according to UNE-EN ISO 80079-36: 2017
|I - MINES||Ma - Normally, foreseeable breakdowns and rare breakdowns, there is no effective source of ignition.|
|Mb - In normal operation and foreseeable breakdowns there is no effective source of ignition.|
|II - OTHER SURFACE INSTALLATIONS|
with explosive gas atmosphere
|Ga - In normal operation, foreseeable breakdowns and rare breakdowns, there is no effective source of ignition.|
|Gb - In normal operation and foreseeable breakdowns there is no effective source of ignition.|
|Gc - In normal operation, there is no effective source of ignition.|
|II - OTHER SURFACE INSTALLATIONS with explosive DUST atmosphere||Da - In normal operation, foreseeable breakdowns and rare breakdowns, there is no effective source of ignition.|
|Db - In normal operation and foreseeable breakdowns there is no effective source of ignition.|
|Dc - In normal operation, there is no effective source of inflammation.|
What is Ignition Temperature in Explosive Atmospheres?
The ignition temperature or flash-point, as indicated in the Directive, is the temperature at which the release of vapors is sufficient for ignition, due to the contribution of energy from an external source.
The maximum surface temperature of the equipment used in Explosive Atmospheres definition is different if referring to Dust or Gas.
In Explosive Dust, the maximum surface temperature matches the maximum authorized temperature that the equipment’s external surface can reach, both in normal and abnormal operation.
When referring to DUST, it is necessary to know the following values:
- T-Inflammation – Inflammation temperature of a dust cloud
- T-Inflammation-5 – Flash temperature of a 5mm thick layer of these same powders.
The chosen temperature value will be the smallest of the values, R1 = (2/3) x TInflamacion and R2 = TInflamación-5 -75.
In case of Gas, the standard contemplates 6 temperature classes:
|TEMPERATURE CLASS REQUIRED BY ZONE CLASSIFICATION||Gas or Vapor ignition temperature in ºC||Material temperature class allowed|
|T1||>450||T1 – T6|
|T2||>300||T2 – T6|
|T3||>200||T3 – T6|
|T4||>135||T4 – T6|
|T5||>100||T5 – T6|
T1 refers to the lowest risk level (low hazardous substances) for mixtures at relatively high ignition temperatures.
T6 refers to the highest level of risk (very dangerous substances) for mixtures at relatively low ignition temperatures.
In certain applications pneumatic pumps, whether referring to diaphragm or piston pumps, and hose reels, may have high surface temperatures due to the fluids they carry. In these cases, the fluid temperature must be taken into account, to determine the temperature class of the equipment.
As an approximate guide, the following maximum temperature values of the fluids to be pumped can be used depending on the materials of the joints or gaskets:
|Gasket material||Highest Temperature allowed ºC|
|PTFE with graphiete||4 to 107|
|EPDM||-51 to 138|
|PTFE with fiberglass||4 to 107|
|Leather||-18 to 104|
|PTFE with mineral filler||4 a 107|
|Nitrile||-12 a 82|
|Polyurethane||-12 a 86|
|PTFE||4 a 107|
Interpretation of ATEX labeling
ATEX Labeling can be quite complex, but basically it must be taken into account that the first part of it refers to the INSTALLATIONS classification according to Directive 2014/34 / EU and the last part refers to the classification of the installed equipment and it is based on the particular regulations of each team.
The following explains the terms on the labeling example below.
It is not always necessary to indicate each and every one of these terms:
refers to the fact that the equipment can be used in Explosive Atmospheres.
‘II 2GD’ refers to the general marking according to the Directive and its meaning is as follows:
’II’ Indicates that the product can be used in Surface Installations with an explosive gas atmosphere. Not at Mines.
’2’ Indicates the equipment category. In this case, category 2 – Equipment with a high level of protection according to Directive 2014/34 / EU.
‘GD’ Indicates that the equipment can be used in Explosive Gas or Dust Atmospheres, according to directive 2014/34 / EU
‘Ex h IIB’, refers to the specific marking of equipment for explosive gas atmospheres.
’Ex’ is used for non-electrical equipment and indicates that it is possible to use it in a potentially explosive atmosphere. ’Ex’ is the conformity with European CENELEC standards symbol for electrical equipment.
’h ’ Refers to the protection type. When it is “h” it indicates that no protection is necessary. Protection types are very specific to the equipment and specific regulations to be followed. Hereby, some general values:
For non-electrical equipment the protection modes are as follows:
|Flow Limitation Casing||fr|
|Immersion in a liquid||k|
|Explosion Proof Casing||d|
|Inflammation Origin Control||b|
For electrical equipment the protection modes are as follows:
SUPPRESSION OF THE SOURCE OF IGNITION
SUPPRESSION OF THE EXPLOSIVE ATMOSPHERE
|Type “n” overpressure||nZ||3G|
|Immersion in oil||o||2G|
CONTAINS THE OUTBURST, NOT THE SPREADING OF THE FLAME
|Explosion proof casing||d||2G|
IIB Refers to a repetition of the Zone Group and the classification of the gas mixture. In this case it refers to Surface Installations and gas mixture B (Ethylene, butadiene)
T5’ refers to the temperature type. In this case the equipment can be used in Explosive Gas Atmospheres with an ignition temperature higher than 100ºC.
Here “T100ºC IP65” may appear instead, it refers to the specific Dust nomenclature.
T100ºC – The equipment can be used in Explosive Atmospheres formed by Powders with an inflation temperature greater than or equal to 100ºC.IP65 – Refers to the leak tightness index of the equipment.
IP65 – Refers to the equipment’s watertightness index. The watertightness index of the equipment can be:
IP5 # Dust tight. This kind of equipment can only be installed in case of non-conductive dusts in zone 22
IP6 # Totally dust-proof.
FIRST FIGURE OF THE IP INDEX
PROTECTION AGAINST SOLID BODIES
|Protected against solid bodies >50 mm||1|
|Protected against solid bodies >12mm||2|
|Protected against solid bodies >2,5mm||3|
|Protected against solid bodies >1mm||4|
|Protected against Dust||5|
|Totally protected against Dust||6|
SECOND FIGURE OF THE IP INDEX
PROTECTION AGAINST LIQUIDS
|Protected against vertical drops of water drops||1|
|Protected against waterfalls inclined at 15º||2|
|Protected against rain water up to 60º from vertical||3|
|Protected against water spray from all directions||4|
|Protected against water jets from all directions, with lance||5|
|Protected against powerful water jets or sea packages||6|
|Protected against the effects of immersion between 15cm and 1m||7|
|Protected against prolonged immersion, in depth and under pressure||8|
‘Gb’ Equipment Protection Level (EPL). In this case, during normal operations and foreseeable breakdowns, there is no effective source of ignition.
‘X’ at the end of ATEX indicates special safe conditions of use, conveyed by the service manual or end-user instructions. For example, data relating to surface temperature as a function of the fluids conveyed by the equipment.
Here are some labeling examples
Suppose we need to install a diaphragm pump at a car dealer in the repair pit area. The property has defined this actual facility area as a dangerous zone with the following characteristics:
- Environment: Group II, as it is a surface installation. It is in a pit but it is not a Mine
- Atmosphere Type: G (gas)
- Definition of Gas:
- Classification: A (propane, butane, ethyl acetate…)
The pump has the following ATEX certification:
Ex II 2GD IIB / IIC T6
Is this label valid for this installation?
The pump will be located in zone 1 with danger of explosion due to the accumulation of Gas mixtures in a pit of an Automobile Dealer.
If we look at the general marking II 2GD we see that it is suitable for:
II – Group II, surface installations
2 – Category 2, equipment with a high level of protection.
G – Suitable for gas atmospheres.
The Zone Definition table:
GAS / LIQUID
Therefore, at Zone 1 , 2G and 1G equipment can be mounted, so it is suitable for this installation.
If you look at the IIB / IIC gas marking, T6 is valid for gases of level B and C. Since it is suitable for level B gas, it can also be used with level A. In addition, the temperature class T6 is the most restrictive for temperatures above 85ºC
CONCLUSION: The indicated pump is SUITABLE to be installed in this area of the facility.
Below, other examples of ATEX marking of various products:
Equipment with Label Exaple 1:
- Equipment for surface facilities only,,only, not mines.
- Suitable for Zone 0, 1 and 2 with Gas and Zone 20, 21 and 22 with dust.
- In explosive Gas atmospheres, this is an equipment with Intrinsic “ia” Safety equipmentSafety equipment for gas -such as Hydrogen with ignition temperatures higher than 135ºC “T4..T6” at surface installations and normally or with foreseeable and rare breakdowns, there is no effective ignition source “Ga”.
- In explosive dust atmospheres, it is protected by “ia” and “ta” enclosures, suitable for explosive atmospheres with combustible suspended particles, non-conductive dust and conductive dust and during normal operations and foreseeable breakdowns or rare breakdowns there is no effective source of inflammation “Da”
Equipment with Example 2 Label:
- Equipment for surface facilities only,,only, not mines.
- Suitable for Zone 1 and 2 for Gas and in Zone 21 and 22 for dust.
- In explosive gas atmospheres, this is an equipment with increased Safety “e” for surface Gas installations, such as Hydrogen with ignition temperatures greater than 85ºC “T6” and during normal operations, foreseeable breakdowns, there is no effective source of inflammation “Gb”.
- In explosive dust atmospheres, it presents enclosure protection “tb”, for explosive atmospheres with combustible suspended particles, non-conductive dust and conductive dust and during normal operations and foreseeable breakdowns, there is no effective source of ignition “Db.
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