ATEX, Intrinsic Safety & Hazardous Area Information

However demanding your application and environment, we can provide you with a complete ATEX monitoring system. Our range of ATEX pressure sensors and transmitters are available in gauge, absolute, vacuum, differential and compound pressure measurement, with custom pressure ranges and all with a 4-20mA output. Our ATEX rated load cells can also be supplied with suitable Zener Barriers enabling you to safely connect the load cells to any electronic device outside of the hazardous area.

Want to discuss your ATEX application? Let us call you…

    Our call back service is only available for UK phone numbers. If you are based outside the UK, please send us an enquiry using the form in the sidebar or the contact us page.

    Please note that this page provides helpful information only, detailed reference should be taken from an appropriate accredited agency or organisation.

    The term ATEX refers to 2 European Directives.  The first being the ATEX 137 Workplace Directive and the second is the ATEX 95 Equipment Directive.

    The ATEX 137 Workplace Directive (also known as 99/92/EC) relates to the minimum requirements needed for the protection of the workforce who may be at risk in explosive atmospheres.

    The ATEX 95 Equipment Directive (also known as 94/9/EC) relates to the use of equipment and systems in potentially explosive atmospheres.

    Protection Concepts
    ZoneHazardProtection Concepts
    0In which an explosive gas/air mixture is continuously present for long periods.Exia or Exs
    1In which an explosive gas/air mixture is likely to occur in normal operation.Exd. Exe, Exib, Exp, Exia, Exs
    2In which an explosive gas/air mixture is not likely to occur in normal operation.All concepts suitable for Zone 0 & 1, ExN, ExO and Exq
    Standards For Methods Of Protection
    Method Of Protection Permitted Zone Of Use In UKCode Letter IEC, EX.., CENELEC, EEX
    General requirement--
    Oil immersion2o
    Pressurisation1 or 2p
    Powder filling2q
    Flameproof1 or 2d
    Increased safety1 or 2e
    Intrinsic safety* 0, 1 or 2ia or ib
    Non-incendive2n #
    Encapsulation1 or 2m
    Special1 or 2s
    * ia: Zone 0, 1, 2 / ib: Zone 1 or 2 but not Zone 0 | # n: used locally in UK
    Gas Grouping
    Gas # Group CENELEC EN 5014, IECRepresentative Gas
    I * (mining)Methane
    IIAPropane
    IIBEthylene
    IICHydrogen
    Temperature Classification
    T Class / IEC 79-7Max. Surface Temp °C
    T1450°C
    T2300°C
    T3200°C
    T4135°C
    T5100°C
    T685°C
    Certification Code (CENELEC marking information - example [EEx ia] IIC T4)
    [EExia]IICT4
    Associated apparatus*Certified to the CENELEC standardExplosion protectedProtection concept (IS)Associated apparatus*Apparatus group (gas group)Temperature classification (not Gp I)
    * (located in safe area and may be connected to hazardous area)
    Device Group & Category
    Device GroupDevice CategoryZone
    IM = Mining-
    MiningM 1-
    Pit Gas &/or Flammable DustsM 2-
    IIG = Gas
    Other Areas1 G0, 1, 2
    Explosive Atmosphere2 G1, 2
    3 G2
    D is added after G in the certification class numberD = Dust
    (i.e. GD) if device is dust category approved also1 D20, 21, 22
    2 D21, 22
    3 D22
    Explanation of the categories:

    1 - Very high safety = device safety must be guaranteed even in case of rare device failures, e.g. simultaneous failure of two components.

    2 - High safety = device safety must be guaranteed if frequent failures can be expected, e.g. failure of one component.

    3 – Safe in normal operation = device safety must be guaranteed in normal operation.

    Note: A number in brackets before device category designation signifies that the device meets the requirements of an additional category to the main one that is specified.
    Example: II (1) 2G signifies that the device meets requirements for both 1 G and 2 G categories
    ATEX

    Find this article interesting? Have a read of our other sensor reference articles.

    Have an ATEX application you want to discuss? Let us call you…

      Our call back service is only available for UK phone numbers. If you are based outside the UK, please send us an enquiry using the form in the sidebar or the contact us page.

      Characteristics of Substances

      Flashpoint

      This is the lowest temperature at which a liquid generates sufficient vapour to support ignition. This vapour can be ignited in many ways including temperature or energy (i.e. a spark).

      Ignition Temperature

      This is the lowest temperature at which the vapour will be ignited. This defines the temperature class.

      Classification of Maximum Surface Temperatures of Electrical Apparatus (CENELEC)
      Temp. ClassMax. Surface Temp.
      T1<450ºC
      T2<300ºC
      T3<200ºC
      T4<135ºC
      T5<100ºC
      T6<85ºC

      Apparatus Group (Energy Ignition)

      All surface industry gases/vapours are classed as Group II gases. Group II is divided into 3 sub groups:

      IIA – High energy is required to ignite. Less intense explosion. (Propane)

      IIB – Less energy is required to ignite. More intense explosion. (Ethylene)

      IIC – Little energy is required to ignite. Most intense explosion. (Hydrogen)

      Characteristics Of Some Common Flammable Materials
      Gas/VapourFlashpointGas GroupIgnition Temp.Temp. Class
      Acetone19ºCIIA535ºCT1
      Butane-60ºCIIA365ºCT2
      Heptane-4ºCIIA215ºCT3
      Ethyl Methyl Ether37ºCIIB190ºCT4
      Note: There is no connection between ignition energy and ignition temperature

      Find this article interesting? Have a read of our other sensor reference articles.

      Interested in our ATEX products? Let us call you…

        Our call back service is only available for UK phone numbers. If you are based outside the UK, please send us an enquiry using the form in the sidebar or the contact us page.

        Why Us?

        • Suppliers of top quality strain gauge sensors and transducers to every corner of industry – UK and worldwide
        • Over 100 years of expert transducer knowledge
        • Our high quality products all come with a 3 year warranty