Explosion protection in Europe

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3 Explosion protection in Europe Electrical equipment basic principles, rules, standards Dieter Herrmann Note: This reference work has been created to the best of our knowledge and belief. We assume no liability for possible errors. The definitive source of information is always the operating manual for the relevant device.

4 The European standards for explosion protection are continuously modified and adapted to IEC standards. The new edition of the book is intended to take this into account. However, the fundamental principles for explosion and explosion protection have remained the same. The book is intended to provide an introduction to explosion protection. There are references to directives, regulations, and standards in which details about explosion protection are specified. Fulda, June 2010 Jürgen Kuhlmei Due to the changes to directives and standards, this technical paper has been revised and adapted to the state of the art. Fulda, April 2017 Dieter Herrmann JUMO GmbH & Co. KG Moritz-Juchheim-Straße Fulda, Germany Phone: Fax: dieter.herrmann@jumo.net Internet: Reprinting is permitted if source is cited! Part number: Book number: FAS 547 Printing date: ISBN:

5 Content 1 Requirements for an explosion Flammable substances (examples) Oxygen Sources of ignition (examples) Potentially explosive areas Potentially explosive atmosphere Hazardous quantity Combustion point Ignition temperature of gas atmosphere Ignition temperature of dust Smoldering temperature of dust Hybrid mixture Electrostatics Summary Legal principles EU directive 2014/34/EU EU directive 1999/92/EC Summary Placement of electrical equipment onto the market Quality assurance in production EU type examination Operating manual Identification marking Alternative identification marking according to equipment protection level (EPL) EU declaration of Conformity Notified European test facilities Obligations of manufacturers and operators Manufacturers Operators Explosion protective measures Primary explosion protection Secondary explosion protection Structural explosion protection Selection criteria for electrical equipment Protection types for gases, vapors, mists Protection types for combustible dust Safety equipment Equipment protection levels (EPLs) Explosion protection in Europe

6 Content 6.5 Equipment with ignition protection type "ia"/"ib"/"ic" Explosion groups Surface temperature temperature classes Explosion group I Explosion group II Explosion group III Division of flammable gases and vapors into explosion groups and temperature classes 37 7 Non-electrical explosion protection Classification into zones Classification into device groups and categories Requirements for electrical equipment Gas Zones (EN ) Ex-zone Ex-zone Ex-zone Dust Zones (EN ) Ex-zone Ex-zone Ex-zone Temperatur limiting for dust in ex zones Relationship between zones and categories Protection types Simple electrical equipment Ignition protection type ex i intrinsically safe Definition of term according to EN Intrinsically safe electrical equipment Wiring Installation of the components Housing Connection terminals Plug connectors Conductor tracks Clearances, creepage distances, and distances in potting Ground Insulation Components on which intrinsic safety depends Explosion protection in Europe

7 Content 16 Supply isolators Safety barriers Brief description Functional principle of safety barriers Safety barriers with galvanic isolation Type testing for intrinsically safe equipment Ignition limit curves (reference curves) Verification of intrinsic safety Connection examples JUMO RTD temperature probes according to ATEX Standards and bibliography Index Explosion protection in Europe

8 Content Explosion protection in Europe

9 1 Requirements for an explosion In industrial operations, such as chemical factories, paint shops, sewage treatment plants, power plants, but also in mining, grain mills, silos and wood processing plants, explosion hazards can occur under certain conditions. Three factors must occur at the same time for this: Flammable substancesoxygen Source of ignition Explosion Figure 1: Conditions for an explosion Another important criterion is the concentration of combustible material and the oxygen-air mixture. The explosion is a fast form of combustion in which the flame propagates at a speed of 1 to 999 m/ s. 1.1 Flammable substances (examples) Gases (hydrogen,,methane, butane, propane, natural gas...) Liquids (gasoline, ether, benzene, toluene, methanol...) Steams (gaseous liquids solvents...) Solids (dusts carbon, powder, aluminum...) 1.2 Oxygen There is oxygen in our ambient air and it is therefore always present. 1.3 Sources of ignition (examples) Sources of ignition provide the energy for the start of combustion. Flames (welding torches, heaters) Hot surfaces (pipes, heating cabinets, overheated bearings) Sparks (light arcs, short circuit, electrostatic discharge) Electrical plants Lightning Chemical reactions JUMO, FAS 547, Edition Requirements for an explosion

10 1 Requirements for an explosion 1.4 Potentially explosive areas Due to the local and operational conditions, a potentially explosive atmosphere in a hazardous quantity can occur. If there is the possibility of a potentially explosive atmosphere arising, explosionprotective measures are required. 1.5 Potentially explosive atmosphere A mixture of air and flammable gases, vapors, mists, or dusts, including common additives such as moisture, creates an explosive atmosphere. A reaction may occur in this mixture that, after ignition, independently spreads to the entire unburned mixture under atmospheric conditions. Here, atmospheric conditions means overall pressure of 0.8 to 1.1 bar and mix temperatures of -20 to +60 C. 1.6 Hazardous quantity With gases, mists and vapors, a hazardous quantity means if 10 liters of the explosive mixture is present as a connected volume in an enclosed space. The size of the room is not crucial. Smaller quantities may also be hazardous. With rooms that are smaller than 100 m 3, a smaller potentially explosive mixture may be considered as a dangerous quantity. As a rule of thumb it may be assumed that the quantity is dangerous in areas with more than 1/10,000 potentially explosive atmosphere. In case of dust, the concentration is in an ignitable range at approximately 40 g/m 3 to 4 kg/m 3 and a particle size < 400 microns. 1.7 Combustion point The combustion point is defined in the standard EN It is the lowest temperature of a liquid at which vapors from the liquid develop under certain standard conditions in such quantities that they are capable of forming a flammable vapor/air mixture. Precise conditions for testing or determining the combustion point are defined. If the temperature of the liquid is safely and permanently 5 C below the combustion point, a potentially explosive atmosphere cannot form. However, the degree of dispersion is not taken into consideration here. If a flammable liquid is sprayed, it can also be ignited if the temperature is below the combustion point. This can occur, for example, with heating oil. "In the case of flammable liquids, the temperature is safely below the lower explosion limit if the temperature on the liquid surface is kept sufficiently (about 5 K to 15 K. see section 3.2 paragraph 4 number 2 letter b of TRBS (English: Technical Rules for Industrial Safety) 2152 Part 1/TRGS (English: Technical Rules for Hazardous Substances) 721) below the combustion point." 1.8 Ignition temperature of gas atmosphere The ignition temperature of combustible gases or liquids is determined in a test device. It is the lowest temperature of a heated surface at which the flammable substance will still ignite as a gas/air or vapor/air mixture. The combustible gases and vapors of flammable liquids are classified into temperature classes according to their ignition temperatures and the equipment according to the surface temperature. It must be ensured that the surface temperatures of the equipment remain below the ignition tem- JUMO, FAS 547, Edition Requirements for an explosion

11 perature in order to prevent ignition. 1 Requirements for an explosion 1.9 Ignition temperature of dust The lowest temperature determined under predetermined test conditions for a hot inside wall of a furnace at which the ignitable mixture of dust with air (dust cloud) can ignite in the furnace Smoldering temperature of dust A layer of dust on equipment may ignite. The lowest temperature of the equipment surface at which this can happen is called the smoldering temperature. The thickness of the dust layer must be defined (EN ) Hybrid mixture Hybrid mixtures are flammable mixtures consisting of gas and dust atmosphere. Devices with gas and dust approval are not automatically usable for hybrid mixtures (the approval is for gas or dust, not for gas and dust). Note: If a dangerous atmosphere could occur at the mounting site an atmosphere that is potentially explosive due to a gases, vapor, or mist and at the same time due to combustible dusts then the safety-related characteristic parameters of the gases, vapors, or mist and the combustible dusts can change. In such cases the suitability of the intended device is to be checked by an appropriate expert body Electrostatics The electrical devices must be designed so that ignition due to electrostatic discharge is prevented during normal usage, maintenance, and cleaning conditions. Electrostatic charges depend on the material, surface, and possible grounding (EN ). Summary Manufacturers of equipment for the potentially explosive area, builders and operators of plants in operations and areas where there is an explosion hazard must take all required precautions according to the relevant laws and regulations applicable in the European Union in order to avoid an explosion. JUMO, FAS 547, Edition Requirements for an explosion

12 2 Legal principles Those who install and operate plant, and the manufacturers of equipment, are obliged by law to observe measures for explosion protection. Two new EU directives will now be decisive for explosion protection across Europe, and have the status of laws. All member states of the European Union are obliged to implement these directives in national law. From July 1st 2003, only such equipment and protective devices may be placed on the market and only such installations may be commissioned that meet the following EU Directives for explosion protect: 2.1 EU directive 2014/34/EU Equipment and protective systems intended for use in potentially explosive atmospheres The directive applies to manufacturers or distributors of equipment and protective systems used in potentially explosive areas. Directive 94/9/EC was to be applied until April 19, It was also known under the name ATEX 100a (95a). ATEX stands for ATmosphéres EXplosibles. The aim of the directive is to protect the health of persons, domestic animals, and goods. Employees, in particular, must be protected from dangers that originate from equipment and protective systems in potentially explosive areas. What do the following mean: Devices: Protective systems: Machines Equipment Stationary or transportable devices Control and equipment parts Measuring and control devices Devices that immediately stop incipient explosions e.g. flame arrester, fire extinguisher lock You will find additional explanations in "ATEX 2014/34/EU GUIDELINES". 2.2 EU directive 1999/92/EC "Directive on minimum requirements for improving the safety and health protection of workers potentially at risk from explosive atmospheres" This directive applies to operators of equipment, plants, and protective devices that are used in potentially explosive areas. It is also known under the name ATEX 118 (137). Requirements are set out for the mounting and maintenance of the devices, as well as protective devices in potentially explosive areas. It pursues the same protection objectives as EU directive 2014/34/EU. JUMO, FAS 547, Edition Legal principles

13 2 Legal principles 2.3 Summary 2014/34/EU Manufacturers EU directive - ATEX AT mosphéres EX plosibles 1999/92/EC Operators In Germany, European directive 2014/34/EU has been implemented in national law in the form of the Product Safety Act (ProdSG). The law entered into force on November 8, The placing on the market of equipment and protective systems for potentially explosive areas is controlled and the technical framework conditions are defined in the associated explosion protection product regulation (11th ProdSV). In Germany, the European directive 1999/92/EC is embedded in the Occupational Safety and Health Law (ArbSch). The associated Industrial Safety Regulation (BetrSichV) from February 3, 2015 defines the requirements for the provision and use of work equipment and the operation of plants. The explosion protection rules give support to DGUV (English: German statutory accident insurance) rule for statutory accident insurance for the implementation of German state occupational health and safety regulations for potentially explosive areas. Dust explosion protection is also legally consolidated across Europe through European directives. Dust explosion protection specifically deals with areas that are at risk due to the build-up of dust, e.g. the inside of containers, silos and apparatus (mills, mixers, etc.) or their surrounding areas due to dust deposits. The first dust explosion identified as such happened as early as 1785 in Italy. In 1979, there was a devastating dust explosion in Germany at the Rolandmühle in Bremen. The result was 14 dead, 17 injured, and material damage amounting to approximately EUR 50 million. High safety requirements and stringent regulations for gas and dust explosion protection have always been in place in Germany. It is therefore relatively easy to implement the innovations from the EU directives. JUMO, FAS 547, Edition Legal principles

14 2 Legal principles Figure 2: Mill after a dust explosion International Europe Germany International Electronic Commission (IEC) creates publications Publication 79 Electrical equipment for potentially explosive atmospheres European Parliament and Council of the European Union issues directives based on a proposal from the Commission 2014/34/EU Use of equipment and protective systems in potentially explosive areas (recast) 1999/92/EC Improving the safety and health protection of workers potentially at risk from explosive atmospheres" European Committee for electrotechnical standardization CENELEC writes European standards(see annex) EN EN onwards Explosion prevention and protection - Basic concepts and methodology Explosive atmospheres - Equipment - General requirements The Federal German government implements EU law in national law German Product Safety Act (ProdSG) Occupational Safety and Health Law (ArbSch) Regulations German Electrotechnical Commission for Standardization DKE (DIN/VDE) harmonizes German standards with European standards The same applies accordingly to the other European member states and Switzerland (VGSEG - Regulation on equipment and protective systems in potentially explosive areas). Table 1: Context of the legal principles for explosion protection JUMO, FAS 547, Edition Legal principles

15 3 Placement of electrical equipment onto the market Directive 2014/34/EU requires Europe-wide procedures for the "placing products onto the market". The following sections describe a possible procedure: 1. The manufacturer maintains an approved quality assurance system for the manufacturing, final acceptance, and testing of its products that are intended for use in potentially explosive areas. 2. The manufacturer or its authorized representative shall request an EU type examination (Chapter 3.2 EU type examination ) for its product at a test facility. The test facility is designated by an EU member state and must be authorized. In Germany this is performed by the German Accreditation Body (DakkS). Designated test facilities are also called "notified bodies". 3. The manufacturer or its authorized representative shall issue an EU declaration of conformity (Chapter 3.4 EU declaration of Conformity ) and apply the product CE identification marking (see EU directive 2014/34/EU - annex). Notified test facility e. g. PTB, TÜV Nord, DEKRA EXAM, electrosuisse (SEV) Submits product for testing Checks the product Creates a test report and issues an EU type examination certificate Manufacturer JUMO Maintains an approved quality assurance system Manufacturing, final acceptance, and testing Performs a conformity assessment Issues the EU declaration of conformity Applies CE identification marking Figure 3: Testing method and placing onto market JUMO, FAS 547, Edition Placement of electrical equipment onto the market

16 3 Placement of electrical equipment onto the market 3.1 Quality assurance in production When applying module B (EU type examination), the manufacturer is obliged to have its quality assurance system evaluated by a notified body (certification body) of its choice for the production area of equipment for explosion protection. It must be ensured that the products for which a type examination certificate was issued are also produced with the same quality and safety. Operation certification according to DIN EN ISO 9001 can form the basis for this. However, this certification alone is not enough according to the legal requirement. There are other requirements for the production of equipment for explosion protection. Additional certification of the production area is therefore required. Figure 4: TÜV 99 ATEX 1454 Q certificate Quality assurance system recognition JUMO, FAS 547, Edition Placement of electrical equipment onto the market

17 3 Placement of electrical equipment onto the market 3.2 EU type examination For equipment and protective systems that are due to be used in the explosion protection zone 0 and/or zone 1 or zone 20 and/or zone 21 (Chapter 8 Classification into zones ) type examinations are required by a designated body (Chapter 3.5 Notified European test facilities ). The notified body must examine the technical documentation and the representative sample of the respective products. This body drafts a test report and issues a type examination certificate. Figure 5: Example of an EU type examination certificate EPS 12 ATEX U for a thermowell without an autonomous function based on ATEX 2014/34/EU Existing EC type examinations based on ATEX 94/9/EC retain their validity. JUMO, FAS 547, Edition Placement of electrical equipment onto the market

18 3 Placement of electrical equipment onto the market Identification marking SEV 09 ATEX 0101X SEV Test facility 09 Year of first issuance ATEX Approved according to European Directive 0101 Serial number X Special conditions Applied standards Identification markings according to EU Directive II 2 G II 2 D Explosion protection II Device group 2 G Category - Gas 2 D Category - Dust Figure 6: Identification marking according to EU standards Ex ib IIC T6... T4 Gb (gas) Ex ib IIIC T70 C C Db (dust) Ex Explosion protection ib Ignition protection type IIC Explosion group T... Temperature class/surface temperature Example of an EU type examination certificate SEV 09 ATEX 0101 X for transmitters according to applicable law based on directive 2014/34/EU European standards EN that are mentioned in the following chapters form the basis of testing. Fundamentally, international standards (IEC) within of meaning of ATEX 2014/34/EU must not be applied in Europe. JUMO, FAS 547, Edition Placement of electrical equipment onto the market

19 3 Placement of electrical equipment onto the market Operating manual The operating manual is part of the type examination. An operating manual must be available for each device or protective system, and it must include at least the following information: Same information as the identification marking of the device or protective system (except for serial number; construction year) Information regarding safe - Startup - Use - Mounting, dismounting - Servicing (maintenance and fault elimination) - Installation - Setup If necessary, the indication of dangerous areas in front of pressure-relief devices If necessary, training information Information which unequivocally allows a decision to be made on whether a device or protective system can be used without risk in the intended area under the expected conditions (observe category) Electrical parameters and pressures, maximum surface temperature and other limit values If necessary, specific conditions of use, including references to unintended use which, from experience, can occur If necessary, the basic features of the tools that can be fitted to the device or protective system The operating manual must be provided in accordance with the decisions of the respective member state in the specified language. JUMO, FAS 547, Edition Placement of electrical equipment onto the market

20 3 Placement of electrical equipment onto the market 3.3 Identification marking Based on the certified quality assurance in production and the type examination certificate, the manufacturer applies the marking relevant for explosion protection and a CE marking to its product (Figure 7). The number of the notified body responsible for the quality assurance system is added to the CE marking. Manufacturer name Operating voltage Type designation Serial number (also includes the year of manufacture) CE marking with test facility indicator Part number Marking for Ex protection Device group Category Explosion protection Ignition protection type Explosion group Temperature class Ambient temperature Maximum voltage, current, power, capacitive and inductive connection values Figure 7: Nameplates of a transmitter for the ex-area JUMO, FAS 547, Edition Placement of electrical equipment onto the market

21 3 Placement of electrical equipment onto the market Figure 8: Example of nameplates for RTD temperature probes for the ex-area Alternative identification marking according to equipment protection level (EPL) EN allows an alternative identification marking to the identification marks of the individual ignition protection standards with some exceptions. The standard classifies the devices for potentially explosive areas into three protection levels, and for mines exposed to firedamp into two protective levels. Ex-areas except for mines exposed to firedamp EPL Ga or Da Device with a "very high" protective level for use in potentially explosive areas, in which there is no ignition risk during normal operation or in case of foreseeable or rare errors/malfunctions. EPL Gb or Db Device with a "very high" protective level for use in potentially explosive areas, in which there is no ignition risk during normal operation or in case of foreseeable errors/malfunctions. EPL Gc or Dc Device with "enhanced" protective level for use in potentially explosive areas, in which there is no ignition risk during normal operation and which have some additional protective measures that ensure there is no ignition risk in case of common to foreseeable device malfunctions. The letters "G" and "D" determine whether the device is suitable for explosive gas atmospheres (G) or for areas with combustible dust (D, dust). Ex-areas above and below ground for mines exposed to firedamp EPL Ma Device with a "very high" protective level for installation in mines exposed to firedamp which ensures the required degree of certainty that there is no risk of ignition during normal operation or in case of foreseeable or rare errors/malfunctions even if the device is still in operation during a gas leak. JUMO, FAS 547, Edition Placement of electrical equipment onto the market

22 3 Placement of electrical equipment onto the market EPL Mb Device with a "very high" protective level for installation in mines exposed to firedamp which ensures the required degree of certainty that there is no risk of ignition during normal operation or in case of foreseeable errors/malfunctions in the time between a gas leak and the device being switched off. The application range of equipment from a specific category or a certain protection level EPL in the corresponding danger zones in the potentially explosive area is shown in Table 5 and Table 6. JUMO, FAS 547, Edition Placement of electrical equipment onto the market

23 3 Placement of electrical equipment onto the market 3.4 EU declaration of Conformity The declaration of conformity must include the following information: Manufacturer's name and address or its authorized representative within the EC Product description EU provisions to which the product corresponds EC type examination certificate number Name, identification number and address of designated body Applied standards Legally binding signature The declaration of conformity must be enclosed with each product delivery. JUMO GmbH & Co. KG Moritz-Juchheim-Straße Fulda, Germany Telefon: mail@jumo.net Internet: JUMO GmbH & Co. KG Moritz-Juchheim-Straße Fulda, Germany EU-Konformitätserklärung EU declaration of conformity / Déclaration UE de conformité Dokument-Nr. CE 505 Document No. / Document n Hersteller Manufacturer / Etabli par Anschrift Address / Adresse JUMO GmbH & Co. KG Moritz-Juchheim-Straße 1, Fulda Produkt Beschreibung Ex-i Speise- und Eingangstrennverstärker Product / Produit Typ/ Serie /38 Typenblatt-Nr Wir erklären in alleiniger Verantwortung, dass das bezeichnete Produkt die Anforderungen der Europäischen Richtlinien erfüllt. We hereby declare in sole responsibility that the designated product fulfills the requirements of the European directives. Nous déclarons sous notre seule responsabilité que le produit remplit les directives européennes. Richtlinie Directive / Directive 2014/30/EU 2014/34/EU [Elektromagn. Verträglichkeit (EMCD)] [Explosionsschutz (ATEX)] bis bis Datum der Erstanbringung des CE-Zeichens auf dem Produkt Date of first application of the CE mark to the product Date de 1ère application du sigle CE sur le produit EU-Baumusterprüfbescheinigung Type examination / Tests échantillon BVS 12 ATEX E 090 X Angewendete Normen/Spezifikationen Standards/Specifications applied / Normes/Spécifications appliquées EN EN EN EN * +A11:2013 Ausgabe: 2013 Ausgabe: 2012* Ausgabe: 2012 Ausgabe: 2010 Anerkannte Qualitätssicherungssysteme der Produktion Recognized quality assurance systems used in production / Organisme notifié agréé nach Richtlinie 2014/34/EU / Directive 2014/34/EU / Directive européenne 2014/34/UE TÜV NORD CERT GmbH, Am TÜV 1, Hannover, Germany Kennnummer 0044 Identification No. 0044, N d'identification 0044 Aussteller: Issued by: / Etabli par: Ort, Datum: Place, date: / Lieu, date: Rechtsverbindliche Unterschrift Legally binding signature Signature juridiquement valable Firma / Company / Société JUMO GmbH & Co. KG, Fulda Fulda, Bereichsleitung Verkauf ppa. Wolfgang Vogl Kommanditgesellschaft, Sitz: Fulda, Amtsgericht Fulda, HRA 302 USt.-Id.-Nr. DE ; Persönlich haftende Gesellschafterin: M. K. JUCHHEIM GmbH, Sitz: Fulda, Amtsgericht Fulda, HRB 17; Geschäftsführer: Dipl.-Ing. Bernhard Juchheim, Dipl.-Kfm. Michael Juchheim Figure 9: Example of an EU declaration of conformity JUMO, FAS 547, Edition Placement of electrical equipment onto the market

24 3 Placement of electrical equipment onto the market 3.5 Notified European test facilities In Germany, as well as in the other EU member states, there are notified test facilities, also referred to as "notified bodies" that are allowed to check and accept specific electrical equipment or systems for potentially explosive areas. A corresponding list is published by the European Commission under "Notified bodies Nando". The EC type examination certificate issued by one of these test facilities must be recognized by all member states, even without inspection. Enclosed is a selection of notified test facilities". Name Country ID No. APRAGAZ A.S.B.L. Belgium 0029 UL International DEMKO A/S Denmark 0539 Denmarks Elektriske Materialkontrol PTB Germany 0102 Physikalisch-Technische-Bundesanstalt DEKRA EXAM GmbH Germany 0158 TÜV Nord CERT GmbH Germany 0044 Technischer Überwachungsverein TÜV Süd Produkt Service GmbH Zertifizierstellen Germany 0123 TÜV Rheinland Industrie Service GmbH Germany 0035 INERIS France 0080 Institut National de L Environnement Industriel et des Risques LCIE France 0081 Laboratoire Central des Industries Électriques EECS Electrical Equipment Certification Service Health and Safety Executive (As of: July 22, 2016: Registered for ATEX 94/9/EC) United Kingdom 0600 SCS Sira Certification Service CESI Centro Elettrotecnico Sperimentale Italiano SNCH Société Nationale de Certification et d' Homologation (As of July 22, 2016: registered for ATEX 94/9/EC) United Kingdom 0518 Italy 0722 Luxemburg 0499 DEKRA Certification B.V. Netherlands 0344 NEMKO Norway 0470 Norges Elektriske Materiellkontroll TÜV-Austria Service GmbH Austria 0408 Technischer Überwachungsverein-Austria SP Sweden 0402 Sveriges Provnings- och Forskningsinstitut LOM Spain 0163 Laboratorio Oficial José Maria de Madariaga electrosuisse SEV (As of July 22, 2016: registered for ATEX 94/9/EC) Switzerland 1258 Table 2: Notified test facilities (extract) in Europe JUMO, FAS 547, Edition Placement of electrical equipment onto the market

25 4 Obligations of manufacturers and operators 4.1 Manufacturers When applying module B (type examination; annex III) and module QA (quality assurance production process; annex IV), the product for delivery must match the prototype for which there is a type examination certificate. Furthermore, the product must have been subjected to routine testing. In routine testing, it should be noted that each manufactured part and each end device that influences the explosion protection is inspected. Random samples are not admissible. The manufacturer confirms this by issuing a declaration of conformity and applying the CE marking. The manufacturer must allow the inspection body access to the acceptance, testing and storage facilities for the purpose of the inspection. The manufacturer shall provide all the relevant documents upon request. After the product's final date of manufacture, the manufacturer shall retain the technical documentation and the declaration of conformity for at least 10 years. 4.2 Operators The operator of electrical equipment and systems in potentially explosive areas also has obligations under EU directive 1999/92/EC. The operator must take measures to ensure that safe working is possible. This includes the preparation of an explosion protection document. This document contains the zone classification of operation, a risk assessment, and the protective measures taken. The operator is responsible for ensuring that only approved and certified equipment can be used in a potentially explosive area. It is required that the devices and systems are checked by a qualified electrician or competent person before initial startup and at regular intervals. Any explosions must be reported to the supervisory authority immediately. If there are any faults or defects that endanger employees or third parties, the device/system may no longer be operated. JUMO, FAS 547, Edition Obligations of manufacturers and operators

26 5 Explosion protective measures In principle, protective measures need to be taken in potentially explosive areas in order to avoid an explosion or minimize the consequences of one. The goal is to prevent a potentially explosive atmosphere being formed (primary explosion protection) or to prevent ignition from taking place (secondary explosion protection). If primary and secondary protective measures cannot be reasonably and reliably implemented, additional structural measures (structural explosion protection) must be taken. Explosion protective measures Primary explosion protection Secondary explosion protection Structural explosion protection Figure 10: Explosion protective measures 5.1 Primary explosion protection The formation of a potentially explosive atmosphere can in principle be avoided as follows: Protective measures: Avoiding, replacing, or limiting combustible substances Use of substances with high combustion points Avoiding exceeding the combustion point using temperature limiting Concentration limiting or monitoring Use of gas detectors Inertization through incombustible gases, e.g. nitrogen, carbon dioxide, noble gases Ventilation measures (natural or technical ventilation) Structural measures (explosion-proof construction, explosion suppression, leak tightness...) Special measures for dust: Regularly clean surfaces where dust can be deposited Favor suction methods for cleaning Do not blow off deposited dust using compressed air Avoid electrostatic charge by grounding Do not perform welding work in the area of dusty equipment and pipelines JUMO, FAS 547, Edition Explosion protective measures

27 5 Explosion protective measures 5.2 Secondary explosion protection Measures for secondary explosion protection must be taken if the primary protective measures are not used or only partially used and the sufficient safety is not ensured. Secondary explosion protection involves avoiding an ignition caused by corresponding sources of ignition. Protective measures: Avoiding sources of ignition (flames, sparks, hot surfaces, etc.) Use of electrical devices that are not a source of ignition Encapsulation of the source of ignition from the surrounding atmosphere 5.3 Structural explosion protection If primary and secondary measures do not provide adequate protection, structural measures need to be taken. Protective measures: Explosion-proof construction Explosion relief Explosion suppression Prevention of flame and explosion transmission JUMO, FAS 547, Edition Explosion protective measures

28 6 Selection criteria for electrical equipment Electrical equipment is used in a wide variety of potentially explosive areas with changing requirements for the device. Detailed information about whether the apparatus is suitable for the operating location is required. To be able to determine this, electrical equipment is divided into groups and precisely labeled (see example in Figure 11 and Figure 12) according to EU directive 2014/34/EU and EU standards (see also EN ). II 1 G Ex ia II C T6 Ga Marking for explosion protection Device group Device category Gas area Explosion protection Protection type Explosion group Further subdivisions of the explosion group for flameproof enclosure and intrinsic safety Temperature class Device protection level Figure 11: Identification marking of electrical equipment for potentially explosive areas - gas JUMO, FAS 547, Edition Selection criteria for electrical equipment

29 6 Selection criteria for electrical equipment In the case of equipment for use in the dust area, instead of the temperature class T1 to T6, the equipment's maximum surface temperature T x is specified. The individual selection criteria, such as ignition protection types, categories, explosion groups, and temperature classes are described in the following chapter. Example: Electrical device in ignition protection type t (EPL Db ) for explosive dust atmospheres with conductive dusts from the IIIC group with a maximum surface temperature of less than 225 C and less than 320 C, tested with a dust layer thickness of 500 mm: Marking for explosion protection II 2 D Ex tb IIIC T225 C T 320 C 500 Db Device group Device category Dust area Explosion protection Protection type Explosion group Max. surface temperature Max. surface temperature for 500 mm dust thickness Device protection level Figure 12: Identification marking of electrical equipment for potentially explosive areas - dust General requirements for all electrical equipment (gas and dust) can be found in EN JUMO, FAS 547, Edition Selection criteria for electrical equipment

30 6 Selection criteria for electrical equipment 6.1 Protection types for gases, vapors, mists Protection type EN Flameproof enclosure d Diagram (Ex area is cross-hatched) S Description of protection type The parts that can ignite a potentially explosive atmosphere are arranged in a housing that, in the event of an explosion of an explosive mixture, withstands the pressure and prevents the explosion from transferring to the potentially explosive atmosphere surrounding the housing. EN Pressurized apparatus p P Penetration of a surrounding atmosphere into the housing of electrical equipment is prevented by keeping an inert gas or air in its internal area under an overpressure relative to the surrounding atmosphere. The overpressure is maintained with or without continuous flushing of the inert gas. EN Powder filling q EN Oil immersion o The parts of equipment that can become a source of ignition are firmly arranged in their position and completely surrounded by filling material in order to prevent an external potentially explosive atmosphere from being ignited. Note: The ignition protection type cannot always prevent the penetration of the surrounding potentially explosive atmosphere into the equipment or the Ex-components or the ignition due to electrical circuits. However, an external explosion is prevented by the small free volumes in the filling material and by the negative pressure of a flame that may possibly progress through the channels in the filling material. The electrical equipment or parts of the electrical equipment are immersed in a protective liquid so that a potentially explosive atmosphere, which may be located above the liquid or outside the enclosure, cannot be ignited. EN Increased safety e keine Zündquelle These measures are taken, with an increased degree of safety, to prevent the possibility of excessively high temperatures and the occurrence of sparks or electric arcs inside or on external parts of the electrical equipment, in which they do not occur during normal operation. EN Intrinsic safety i R L C = This ignition protection type has gained considerable importance through the development of measurement control technology. It does not relate to individual devices or equipment, but rather to electrical circuits. They consist of intrinsically safe electrical equipment and associated electrical equipment which are subject to clearly separate requirements. JUMO, FAS 547, Edition Selection criteria for electrical equipment

31 6 Selection criteria for electrical equipment Protection type EN Intrinsically safe systems EN : Equipment with equipment protection level (EPL) Ga EN Pressurized enclosure "p" and forced ventilation "v" EN Non-sparking n Diagram (Ex area is cross-hatched) L N L N Description of protection type This standard is a supplement to EN intrinsic safety i, the stipulations of which, with the exception of the set marking in Chapter 13 must be applied to electrical equipment in intrinsically safe electrical systems. This refers to the entirety of the connected electrical equipment, which is documented with a system description and with which the circuits, that need to be used as a whole or partly in the potentially explosive area, are intrinsically safe electrical circuits. This standard sets out alternative requirements for the design, testing and marking of electrical devices that meet the equipment protection level (EPL) Ga. This standard includes requirements for the design, construction, evaluation, testing and marking of rooms that are protected by a pressurized enclosure or forced ventilation, or both. This standard is applied for electrical equipment and components from group II category 3 G (zone 2). The equipment is not capable of igniting a surrounding potentially explosive atmosphere in normal operation. EN Encapsulation m R, C, L The parts that could ignite a potentially explosive atmosphere through sparks or warming are enclosed in a potting compound so that the potentially explosive atmosphere cannot be ignited. EN Optical radiation op Use suitable means to prevent the optical radiation from penetrating potentially explosive areas and causing the atmosphere to ignite. Optical radiation can be controlled by lasers, LEDs, lamps, fiber optic cables, etc. The optical devices mentioned are increasingly used for measuring, monitoring and communication tasks, amongst others. Table 3: Overview of the ignition protection types for gases, mist, vapors and dusts JUMO, FAS 547, Edition Selection criteria for electrical equipment

32 6 Selection criteria for electrical equipment 6.2 Protection types for combustible dust Protection type EN Dust explosion protection by housing Diagram (Ex area is dotted) Description of protection type This standard describes the protection provided by housing and with a limited surface temperature for use in potentially explosive dust atmospheres. It specifies requirements for the design, construction and testing of electrical devices and Ex-components. EN Pressurized enclosure "pd" O P An internal overpressure greater than the surrounding atmosphere prevents the establishment of a potentially explosive dust atmosphere inside the housing. From August 25, 2017, only EN is applicable. Table 4: Overview of the ignition protection types for dusts 6.3 Safety equipment EN standard is entitled "Safety equipment for the safe operation of devices with regard to explosion hazards". It describes the requirements for the function of safety equipment, surveillance equipment and control units that are used in conjunction with the protection concept for equipment in potentially explosive atmospheres. The function has to be reliable for its intended use. This should be expressed in conditions that ensure the device can maintain the required level of safety at all times. The EN standard applies to the non-electrical explosion protection for safety equipment. This standard incorporates the requirements of DIN EN "Non-electrical equipment for use in potentially explosive atmospheres - Part 1: Basic method and requirements; German version EN ", the contents of which also apply to devices whose design corresponds to the aforementioned standard. The current revision of the EN standards series is implemented in the EN ISO standards series. Some new versions already exist here. For example, the EN standard part was converted into EN ISO Non-electrical devices have long been used in potentially explosive areas and extensive experiences have been had with protective measures that reduce the risk of ignition to a reasonably safe level. In order to prevent potential sources of ignition from taking effect during normal operation, a malfunction or a rare malfunction, it is possible to install sensors in the device so that looming dangerous conditions can be detected at an early phase of the malfunction before this malfunction can turn into a source of ignition. The (counter) measures applied can then be automatically initiated by direct connections between the sensors and the ignition protection system or manually by issuing a warning to the device operator. For further information about this, please see Chapter 7 Non-electrical explosion protection. JUMO, FAS 547, Edition Selection criteria for electrical equipment

33 6 Selection criteria for electrical equipment 6.4 Equipment protection levels (EPLs) The equipment protection levels (EPL) have been introduced in order to have an alternative procedure in place of the previous procedure when selecting devices for potentially explosive areas. The basic assignment of the EPL according to the table below (defined in EN ) results from classification of potentially explosive areas into zones (see Chapter 8). Zone Equipment protection levels (EPL) 0 Ga 1 Ga or Gb 2 Ga, Gb or Gc 20 Da 21 Da or Db 22 Da, Db or Dc Table 5: Relationship between zones and EPLs If EPLs are specified in the risk analysis, they must be taken into account when selecting a device. The relationship between devices with various ignition protection types and the EPL is shown in the table below. EPL Protection type Short In accordance with description Ga Intrinsic safety ia EN Die-cast enclosure ma EN Two independent ignition protection types that each - EN fulfill the EPL "Gb" Protection of devices and transfer systems op is EN that use optical radiation Gb Flameproof enclosure d EN Increased safety e EN Intrinsic safety ib EN Die-cast enclosure m, mb EN Oil immersion o EN Pressurized enclosure p, px, py, EN pxb, pyb Powder filling q EN Protection of devices and transfer systems that use optical radiation op is, op sh, op pr EN JUMO, FAS 547, Edition Selection criteria for electrical equipment

34 6 Selection criteria for electrical equipment EPL Protection type Short description Gc Intrinsic safety ic EN Die-cast enclosure mc EN Non-sparking n or na EN Gas-proof nr EN Energy limitation nl EN Spark-generating devices nc EN Pressurized enclosure pz or pzc EN Protection of devices and transfer systems that use optical radiation op is, op sh, op pr In accordance with EN Da Die-cast enclosure ma EN Protection by enclosure ta EN Intrinsic safety ia or iad EN Db Die-cast enclosure mb EN Protection by enclosure tb EN Pressurized enclosure pxb, pyb EN Intrinsic safety ib EN Dc Die-cast enclosure mc EN Protection by enclosure tc EN Pressurized enclosure pzc EN Intrinsic safety ic EN Table 6: Relationship between ignition protection types and EPL JUMO, FAS 547, Edition Selection criteria for electrical equipment

35 6 Selection criteria for electrical equipment 6.5 Equipment with ignition protection type "ia"/"ib"/"ic" Intrinsically safe electrical equipment (Chapter 18 Type testing for intrinsically safe equipment ) and intrinsically safe parts from associated electrical equipment must be allocated to a protection level "ia", "ib", or "ic" according to EN These protection levels are defined within EN as follows: Protection level "ia" Protection level "ib" Protection level "ic" Intrinsically safe electrical circuits for electrical equipment with protection level "ia" They must not cause any ignition in response to two countable errors during normal operation and under unfavorable conditions. Intrinsically safe electrical circuits for electrical equipment with protection level "ib" They must not cause any ignition in response to one countable error during normal operation and under unfavorable conditions. Intrinsically safe electrical circuits for electrical equipment with protection level "ic" They must not cause any ignition during normal operation. The error concept does not apply. The safety factor is 1.5 for spark ignition with "ia" and "ib" and it is 1.0 for "ic", with regard to the voltage or the current, or a combination of both. Table 7: Assignment of intrinsically safe equipment to a protection level Category "ia" is a requirement for the use of equipment in explosion zone 0. Equipment from categories "ia" or "ib" can be used in explosion zones 1 and 2. Equipment with protection level "ia", "ib", or "ic" can be used for explosion zone 2. The classification into explosion zones is explained in Chapter 8 Classification into zones. JUMO, FAS 547, Edition Selection criteria for electrical equipment

36 6 Selection criteria for electrical equipment 6.6 Explosion groups Due to locally different environmental influences, electrical equipment for potentially explosive areas is divided into groups. A distinction is drawn here between explosion groups I, II, and III. Explosion group I Explosion group II Explosion group III Electrical equipment for mines susceptible to firedamp (e.g. mining with coal dust, methane gas) Electrical equipment for all potentially explosive areas except for mines susceptible to firedamp (e.g. chemical industry with dyes, acetylene) Electrical equipment for all potentially explosive dusty atmospheres except for mines susceptible to firedamp (e.g. fibers, flour, metal) Table 8: Explosion groups Group II is divided into groups for the ignition protection types "Flameproof enclosure d", "Intrinsic safety i", and the ignition protection type n (na, nc, nr). Due to the wide application area of different combustible substances and gases with different ignition energies, there is a subdivision into the groups IIA, IIB, and IIC. Explosion group II IIA IIB IIC Typical test gas Propane Ethylene Hydrogen Required ignition energy (milliwatt seconds) High 0.26 mws Medium 0.06 mws Low mws Table 9: Explosion groups IIA, IIB and IIC Increasing identification letters indicate the rising explosion hazard of the gases. Hydrogen needs the lowest ignition energy and thus poses the greatest danger of explosion. Equipment for explosion group IIC is automatically suitable for use in groups IIA or IIB. Explosion group IIB can also be used in IIA. In the case of "Flameproof enclosure" (EN ), gases and vapors are subdivided based on a maximum experimental safe gap (MESG). The approach is based on the fact that, in the event of ignition, only a small amount of energy can escape through a gap in the housing. The escaping energy is below the minimum ignition energy of the surrounding dangerous explosive atmosphere. Information according to EN Explosion group II IIA IIB IIC Maximum experimental safe gap (MESG) > 0.9 mm 0.5 to 0.9 mm < 0.5 mm Table 10: Maximum experimental safe gap JUMO, FAS 547, Edition Selection criteria for electrical equipment

37 6 Selection criteria for electrical equipment In the case of "Intrinsic safety" (EN ), gases and vapors are subdivided based on the ratio of their minimum ignition current to the minimum ignition current of laboratory methane (MIC). The procedure for determining the MIC ratio is described in appendix A of the European standard EN Information according to EN Explosion group II IIA IIB IIC MIC ratio > to 0.8 < 0.45 Table 11: Miminum ignition current Explosion group III is also subdivided into three stages: Explosion group III IIIA IIIB IIIC Materials Combustible lint Non-conductive Conductive dust dust Table 12: Explosion group IIIA, IIIB and IIIC JUMO, FAS 547, Edition Selection criteria for electrical equipment

38 6 Selection criteria for electrical equipment 6.7 Surface temperature temperature classes In a potentially explosive atmosphere, electrical equipment with a high surface temperature can cause a thermal ignition Explosion group I A maximum surface temperature is generally defined for electrical equipment in explosion group I: 150 C with layered coal dust deposit, 450 C without a coal dust deposit Explosion group II The ignition temperature for combustible gases has been determined and divided into temperature classes for explosion group II. Electrical equipment is assigned to the temperature classes according to its maximum surface temperature (EN ). Temperature class Maximum surface temperature of the equipment Ignition temperature of the combustible materials T1 450 C > 450 C T2 300 C > C T3 200 C > C T4 135 C > C T5 100 C > C T6 85 C > C Table 13: Explosion group II The lowest ignition temperature of the corresponding potentially explosive atmosphere must be higher than the maximum surface temperature of the electrical equipment The limit temperature of the electrical equipment must not be exceeded, even in the event of a malfunction A safety distance of at least 10 K for T1 and T2, and 5 K for T3 to T6 must be taken into account Example 1: Gasoline has an ignition temperature of 220 to 300 C, which means that only electrical equipment from temperature classes T3 to T6 can be used in this atmosphere. Example 2: In the event of a malfunction, electrical equipment has a surface temperature of 140 C. It may therefore only be used for temperature classes T1 to T3. Operation is not possible in an atmosphere with, for example, carbon disulfide or ethyl ether (Chapter 6.8 Division of flammable gases and vapors into explosion groups and temperature classes ) Explosion group III For devices from group III, the maximum surface temperature is determined with and without a dust layer( (Chapter 10.3 Temperatur limiting for dust in ex zones ). JUMO, FAS 547, Edition Selection criteria for electrical equipment

39 6 Selection criteria for electrical equipment 6.8 Division of flammable gases and vapors into explosion groups and temperature classes Explosion group Temperature class T1 (450 C) T2 (300 C) T3 (200 C) T4 (135 C) T5 (100 C) T6 (85 C) I Methane IIA Acetone (540 C) 1.2 dichloroethane (440 C) Gasoline ( C) Acetaldehyde (140 C) Ammonia (630 C) Cyclohexanone (430 C) Diesel ( C) Benzene (555 C) i-amyl acetate (380 C) Jet fuel ( C) Ethane (515 C) n-butane (365 C) Heating oil ( C) Ethyl acetate (460 C) n-butyl alcohol (340 C) n-hexane (240 C) Acetic acid (485 C) Carbon monoxide (605 C) Methanol (455 C) Propane (470 C) Toluene (535 C) IIB City gas (560 C) Ethyl alcohol (425 C) Ethylene glycol (335 C) Ethyl ether (180 C) Ethylene (425 C) Hydrogen sulfide (270 C) Ethylene oxide (440 C) IIC Hydrogen (560 C) Acetylene (305 C) Carbon disulfide (95 C) Table 14: Temperature classes/gas groups (extract) JUMO, FAS 547, Edition Selection criteria for electrical equipment

40 7 Non-electrical explosion protection The standards series EN is entitled "Non-electrical equipment for use in potentially explosive areas". In the course of standards processing, EN ISO was published in 2016 as a successor to EN A revision of the additional parts of the standards series EN is anticipated. Basic principles and requirements EN ISO (EN until 2016, transitional period until 2019) Ignition protection types and standards fr Flow-restricting enclosure EN d Flameproof enclosure EN c Constructive safety EN ISO (EN until 2016) b Ignition source monitoring EN ISO (EN until 2016) IPL (Ignition Prevention Level) Ignition protection levels 1 and 2 k Liquid enclosure EN ISO (EN until 2016) JUMO, FAS 547, Edition Non-electrical explosion protection

41 8 Classification into zones Since a dangerous explosive atmosphere will not be permanently present in a potentially explosive area, these areas are classified into zones according to the probability of their occurrence. You will find a classification of the zones in "Technical regulations for operational safety TRBS 2152" and also in the standards EN (gas) and EN (dust). Ex zones Includes areas where a dangerous, potentially explosive atmosphere... Gases, vapors, mist (EN ) Zone 0 is present permanently or for the long-term [> 1000 hours/year] Zone 1 Zone 2 Dust (EN ) Zone 20 Zone 21 Zone 22 occurs occasionally [10 to 1000 hours/year] occurs only rarely and then only briefly [< 10 hours/year] is present permanently or for the long-term or frequently present in the form of a cloud of flammable dust in the air [> 1000 hours/year] occurs occasionally for a short period of time due to whirling up of deposited dust [10 to 1000 hours/year] occurs only rarely and then only briefly [< 10 hours/year] This usually includes... only the inside of containers or inside of apparatus the immediate vicinity of zone 0, loading hatches, filling/draining devices, etc. the area surrounding zone 0, 1 around flange connections only the inside of apparatus, containers (mills, driers, mixers), pipes the surrounding area, e.g. dust removal or filling stations, or areas of dust deposits areas where dust can escape from leaks and dust deposits can form No effective ignition source... in undisturbed operation, in case of rare malfunctions and frequent malfunctions in undisturbed operation, and in case of rare malfunctions in undisturbed operation in undisturbed operation, in case of rare malfunctions and frequent malfunctions in undisturbed operation, for whirled up dust and in case of rare malfunctions for deposited dust in undisturbed operation Tabelle 15: Classification into zones The plant installer or operator must assess whether there is an explosion hazard in an area and perform a corresponding zone classification. JUMO, FAS 547, Edition Classification into zones

42 8 Classification into zones Figure 13: Example: Hazardous goods transport Figure 14: Example: Use of paints or lacquers When effectively locked, the area is vacuumed before the actual painting process and thus prevents the formation of a potentially explosive atmosphere. If there is a locking mechanism in place, zone 2 (highlighted in gray) is formed. JUMO, FAS 547, Edition Classification into zones

43 8 Classification into zones Figure 15: Example: Waste water treatment plant Digester with stairwell Figure 16: Example: Chemical industry production JUMO, FAS 547, Edition Classification into zones

44 8 Classification into zones Figure 17: Example: Production plant with and without surveillance JUMO, FAS 547, Edition Classification into zones

45 9 Classification into device groups and categories Devices are also additionally classified into device groups and categories according to EU directive 2014/34/EU. The allocation to a device group and category is part of the prescribed identification marking of devices (Chapter 3.3 Identification marking and the following). The specifications clearly state in which zone the devices can be used. Device group Category Area of application Ex-areas above and below ground for mines exposed to firedamp I M1 Areas at risk long-term or permanently due to mine gas (dusts are also considered) I M2 Areas that may be at risk due to mine gas (dust are also considered) Device group I I I Category 1G 1D 2G 2D 3G 3D Area of application Ex-areas except for mines exposed to firedamp Gases, mist, vapors dusts Gases, mist, vapors dusts Gases, mist, vapors dusts Very high level of safety Safe in case of two independent errors Two redundant protective measures Further operation must be guaranteed! High level of safety It must be possible to switch off equipment! Very high level of safety. Two independent errors. Two redundant protection measures. High level of safety. Normal level of safety. Table 16: Classification in groups and categories JUMO, FAS 547, Edition Classification into device groups and categories

46 10 Requirements for electrical equipment This chapter includes a brief summary of the requirements for electrical equipment in individual exzones. Further details can be found in the respective regulations Gas Zones (EN ) Ex-zone 0 Only electrical equipment that corresponds to a standardized ignition protection type may be used (Chapter 6 Selection criteria for electrical equipment ). Electrical equipment and electrical circuits may be used in zone 0 if they comply with EN , device level Ga. Lines must be protected against mechanical damage, e.g. using a steel reinforcement Cables and lines of the intrinsically safe electrical circuits must be marked. If color markings are applied, the color blue must be used Potential equalization is required for plants in potentially explosive areas An interconnection of several intrinsically safe electrical circuits is not permitted without renewed certification by a recognized test facility As an alternative, double protection (redundancy of two independent ignition protection types according to EN ) can be used to achieve explosion protection. A zone separation with a separation element is required for a "Gb" protection level (e.g. "ib" ignition protection type) if the product is to be used in zone 0 as a category 1 device. As the "ia" ignition protection type directly fulfils the "Ga" protection level, no further measures are required here in the form of a separation element Ex-zone 1 Only electrical equipment that corresponds to a standardized ignition protection type may be used (Chapter 6 Selection criteria for electrical equipment ). Electrical equipment must comply with at least the "Gb" protection level The corresponding electrical equipment, such as voltage supply, safety barriers, etc, must be set up outside the danger zone if they do not have explosion protection through another ignition protection type If several intrinsically safe electrical circuits are interconnected, mathematical proof of intrinsic safety must be provided Interconnecting equipment in intrinsically safe circuits is permitted. The equipment must not be overloaded in terms of current or voltage. Intrinsically safe connecting cables must not be routed together with other connecting cables Cables and lines of the intrinsically safe electrical circuits must be marked, if with a color - then blue JUMO, FAS 547, Edition Requirements for electrical equipment

47 Ex-zone 2 10 Requirements for electrical equipment Equipment may be used that is suitable for use in zone 0 or 1 Electrical equipment must comply with at least the "Gc" protection level and must meet the basic health and safety requirements Intrinsically safe equipment that at least meets the "ic" protection level is permitted Simple electrical equipment (see EN ) For the equipment for zone 2, the following information, amongst others, must be provided by the manufacturer: Suitability for use in zone 2 Information about the operational maximum surface temperature; classification in a temperature class For lights: Information about the suitability for outdoor use and/or in case of mechanical danger JUMO, FAS 547, Edition Requirements for electrical equipment

48 10 Requirements for electrical equipment 10.2 Dust Zones (EN ) Ex-zone 20 Only electrical equipment that has been specially tested and certified for this purpose may be used (EC type examination) The housing must comply with the dust resistance IP6X according to EN The maximum permitted surface temperature must be specified Device identification II 1D Ex-zone 21 An EC type examination is required The housing must comply with the dust resistance IP6X according to EN 60529, for device group IIIA IP5X The maximum permitted surface temperature must be specified Device identification II 2D Ex-zone 22 Electrical equipment may be used without special inspection documents, provided that they comply with a standardized ignition protection type and fulfil the following stipulations The equipment must comply with at least the dust resistance IP6X according to EN 60529, for device group IIIA and IIIB IP5X Device identification II 3D Important information: With electrically conductive dust, type-tested devices from at least category II 2D must be used in zone 22. JUMO, FAS 547, Edition Requirements for electrical equipment

49 10 Requirements for electrical equipment 10.3 Temperatur limiting for dust in ex zones The equipment's surface temperature must not exceed the point at which clouds of dust or dust deposited on equipment could ignite: The following condition must be met (see EN ): The surface temperature must not exceed 2/3 of the ignition temperature in C of the respective dust/air mixture With a dust layer of 5 mm, the surface temperature must not exceed the smoldering temperature minus 75 C of the respective dust. With a dust layer >5 mm and <50 mm, a further reduction in the temperature of the surfaces is required. Maximum permissible surface temperature of the equipment, in C Thickness of layer, in mm Smoldering temperature for a 5 mm thick layer 400 C T 5 mm 320 C T < 400 C 5 mm 250 C T < 320 C 5 mm Figure 18: Reduction of the maximum permissible surface temperature as the thickness of the dust layer increases For systems where the dust layer thickness for housings is >50 mm (procedure A) or >12.5 mm (procedure B), it is permitted to specify the maximum surface temperature T L, e.g. T L = T C. In addition to the surface temperature in C, the layer thickness is specified in mm. The manufacturer determines the layer thickness. JUMO, FAS 547, Edition Requirements for electrical equipment

50 11 Relationship between zones and categories Directive 1999/92/EC Zone classification Definition Gas Dust Potentially explosive atmosphere present Directive 2014/34/EU Equipment requirement Category Gas Zone 0 Zone 20 Constantly, long-term, frequently 1G 1D Zone 1 Zone 21 Occasionally 2G 2D Zone 2 Zone 22 Rarely and short-term 3G 3D* *In the case of conductive dust, electrical equipment from at least category 2D must be used. Dust Table 17: Classification in zones and categories JUMO, FAS 547, Edition Relationship between zones and categories

51 12 Protection types The housing of the electrical equipment used in different zones must comply with specific protection types. The table shows the relationship between the indicators and the protective measures. It is based on EN 60529, in which the test criteria are also described. Example: IP54 5 = dustproof 4 = splash-proof IPXX First digit Second digit Indicator Contact protection Foreign object Water protection 0 No protection No protection No protection 1 Touch with back of the hand Foreign object 50 mm Vertically dripping water diameter 2 Touch with fingers Foreign object 12.5 mm Diagonally (15 ) dripping water diameter 3 Touch with tool Foreign object 2.5 mm Spray water at an angle up to 60 diameter 4 Touch with wire Foreign object 1.0 mm Splash water from all directions diameter 5 Touch with wire Dustproof Water jet 6 Touch with wire Dust-tight Strong water jet Temporary immersion in water Permanent immersion in water Table 18: Protection types of housings JUMO, FAS 547, Edition Protection types

52 13 Simple electrical equipment EN allows simple electrical equipment inside ex-zone 0 under the following conditions: It must comply with building regulations according to EN It must not contain its own voltage source (see maximum values) It must not contain a potential source of ignition (take surface warming into account) The equipment is operated in an intrinsically safe electrical circuit It must be assigned to a temperature class Energy sources Passive construction elements Energy storage Thermocouple Photodiode Max. values 1.5V; 100mA; 25mW Switches Resistors Simple semiconductor components Potentiometers Condenser Coil Table 19: Simple electrical equipment JUMO, FAS 547, Edition Simple electrical equipment

53 14 Ignition protection type ex i intrinsically safe The Ex "i" ignition protection type is one of the secondary explosion protective measures. It is required if the emergence of a potentially explosive atmosphere cannot be prevented. Therefore, measures must be taken so that the energy necessary for the ignition of the explosive atmosphere is not released. This energy is produced: By electrical equipment or cables heating up By sparks that occur when opening and closing the electrical circuit during operation or in the case of an error with a short circuit or ground fault By sparks caused by discharging electrostatic energy. This can be prevented by limiting: Voltage Current Power Capacitances Inductances The energy produced during operation or in the event of an error is minimized by this limiting to such an extent that the ignition does not take place. JUMO, FAS 547, Edition Ignition protection type ex i intrinsically safe

54 14 Ignition protection type ex i intrinsically safe 14.1 Definition of term according to EN Intrinsically safe electrical circuit The energy of the electrical circuit is limited so that it cannot cause an ignition. This applies to both spark formation and thermal effects. The test conditions with specific potentially explosive atmospheres are specified. The tests comprise uninterrupted operation and defined fault conditions. Electrical equipment Electrical equipment is the collective term for electrical components and electrical circuits or parts of electrical circuits generally found together within a single housing. Intrinsically safe electrical equipment Electrical equipment in which all electrical circuits are intrinsically safe. Associated electrical equipment Electrical equipment in which not all electrical circuits are intrinsically safe. In terms of construction, the non-intrinsically safe electrical circuits cannot have an effect on the intrinsically safe electrical circuits. The associated equipment is identified through brackets: e.g. II (1) G [Ex ia] II C. Associated electrical equipment can be used in potentially explosive areas provided it has the corresponding protection (ignition protection type according to EN ). In the event of insufficient protection, it must be used outside of the potentially explosive area. Example: A transmitter (JUMO dtrans T02) is not in the potentially explosive area, however it is connected to a thermocouple in the potentially explosive area. Only the input circuit of the transmitter is intrinsically safe. Operation without faults Intrinsically safe or associated electrical equipment operates normally if it is electrically and mechanically consistent with its nominal values. It has to be used within the limits that have been set by the manufacturer. Faults Faulty components and separations, insulations or faulty connections between components must be regarded as faults if the intrinsic safety of an electrical circuit depends on them. Remark: If a fault leads to one or several secondary faults, the primary and secondary faults are considered as a single fault The use of a spark test device in an electrical circuit to cause interruptions, short circuits or ground faults is regarded as testing the undisturbed operation Components/assemblies that are not prone to failure Components and assemblies that do not deteriorate during operation or storage in such a way that they impair the intrinsic safety of the electrical circuit. They are considered to be non-susceptible to failure during the tests on intrinsic safety. JUMO, FAS 547, Edition Ignition protection type ex i intrinsically safe

55 15 Intrinsically safe electrical equipment The requirements of EN intrinsic safety "i" section 6 must be considered in so far as they contribute to the ignition protection type of intrinsically safe equipment and associated equipment. The general conditions according to EN must also be considered Wiring Diameter Wire cross-section Max. admissible current for the classification into temperature classes T1 to T4 and group I T5 T6 mm mm 2 A A A Table 20: Classification of the copper wiring into temperature classes (EN ) 15.2 Installation of the components The components must be securely fastened to prevent a reduction in the distances. When using a potting compound, you must make sure that the components or the connections are not damaged during potting Housing If the intrinsic safety might be affected by access to conductive parts, a housing with a protection type of at least IP20 according to EN must be provided. For mines, underground and overground mining, the protection type IP54 according to EN is generally required Connection terminals The minimum distance of intrinsically safe and non-intrinsically safe connection parts or bare conductors is 50 mm. Separation by insulating or metal grounded walls is possible Plug connectors They have to be separated between intrinsically safe and non-intrinsically safe circuits and securely protected against interchanging. JUMO, FAS 547, Edition Intrinsically safe electrical equipment

56 15 Intrinsically safe electrical equipment 15.6 Conductor tracks Minimum width of the conductor track Max. admissible current for the classification into temperature classes T1 to T4 and group I T5 T6 mm A A A Table 21: Classification of the conductor tracks on circuit boards into temperature classes (extract from EN ) JUMO, FAS 547, Edition Intrinsically safe electrical equipment

57 15 Intrinsically safe electrical equipment 15.7 Clearances, creepage distances, and distances in potting Clearances, creepage distances, and distances in potting between bare conductive parts of an intrinsically safe and non-intrinsically safe electrical circuit of two different intrinsically safe electrical circuits of the same electrical circuit of an electrical circuit and grounded metal parts are considered as not prone to failure if the conditions from table 22 are met Voltage (peak value) Table 22: Clearances and creepage distances and separation distances (EN ) 15.8 Ground Clearance Separation distance through potting Separation distance through fixed insulation Creepage distance in air Creepage distance under the protective layer Creepage current (CTI) V mm mm mm mm mm Protection ia, ib ic ia, ib ic ia, ib ic ia, ib ic ia, ib ic ia ib, ic level * 2.7 * * k * * 4.5 * * 32.0 * * * * 4.7 k * * 6.0 * * 50.0 * * * * 9.5 k * * 10.0 * * * * * * 15.6 k * * 16.5 * * * * * * Proof of compliance with the CTI requirements of the insulating material must be provided by the manufacturer. With voltages up to 10V, it is not necessary to set a creepage current value for insulating materials. * No values are suggested for these voltages at present. If grounding an intrinsically safe electrical circuit is required for functional or safety reasons, the type of grounding must be so as to avoid detrimental effects to the intrinsic safety of the electrical circuit. JUMO, FAS 547, Edition Intrinsically safe electrical equipment

58 15.9 Insulation 15 Intrinsically safe electrical equipment Insulation must be guaranteed: Between an intrinsically safe electrical circuit and chassis; minimum test alternating voltage 500 V rms, 1 min. Between intrinsically safe and non-intrinsically safe electrical circuit; minimum test alternating voltage 1500 V rms, 1 min. Figure 19: Insulation requirements using the example of an intrinsically safe electrical circuit Components on which intrinsic safety depends The technical construction of components is precisely defined in section 7 of EN The most important are: Maximum load bearing capacity of the components 2/3 of the nominal values of U,I,P Connectors must not be confused Voltage limiting semiconductors must be able to carry a potential 1.5-times the short circuit current, without cutting out Voltage limiting semiconductors must only be used in the "ib" category Components that are prone to failure have to be executed 2 or 3 times In the case of components that are not prone to failure, a simple execution is sufficient The components are defined in EN , section 8. JUMO, FAS 547, Edition Intrinsically safe electrical equipment

59 16 Supply isolators Supply isolators are used to attain a safe galvanic isolation between the potentially explosive zones and the non-explosive area. For example, they provide two-wire transmitters with an operating voltage and transfer the measurement signal galvanically isolated to the output. The power supply to the two-wire transmitter is limited. With a galvanic isolation, there is no direct electrical connection between the electrical circuits. The applied voltages are crucial for the isolation coordinates. With a safe galvanic isolation, double or reinforced insulation must be provided. The supply isolator provides galvanic isolation between the auxiliary energy and the intrinsically safe input circuit, the auxiliary energy and the output circuit, as well as between the input and output circuit. Thanks to the existing galvanic isolation, the supply isolator can be used in conjunction with devices in all zones. Figure 20: Use of a supply isolator In some cases, you can also use a safety barrier according to EN and EN instead of a supply isolator. JUMO, FAS 547, Edition Supply isolators

60 17.1 Brief description 17 Safety barriers Safety barriers are passive networks to separate intrinsically safe circuits from circuits that are not intrinsically safe, without using electrical isolation. By building them into the circuit, it becomes possible to use normal instrumentation and installation in the non-intrinsically-safe section of the circuitry, but no voltage greater than 250 V is permitted to appear. A disadvantage of safety barriers is that they have a relatively high electrical resistance. This must be taken into account for lead compensation. Safety barriers are always wired into the circuit outside the Ex area. Figure 21: Block diagram of a safety barrier One disadvantage of safety barriers is that they only limit current and voltage. Power limitation, as is the case with current transmitters (e.g. JUMO dtrans T02 Ex i, 28 mw), does not exist with the zener barrier. JUMO, FAS 547, Edition Safety barriers

61 17 Safety barriers 17.2 Functional principle of safety barriers Safety barriers are charged with limiting the current and voltage fed into an intrinsically safe electrical circuit in such a way that neither sparks nor hot surfaces can cause an ignition. Safety barriers consist of three major components: Zener diodes for voltage limitation Resistors for current limiting Safety devices to protect the zener diodes Safety barriers are not usually galvanically isolated between input and output. This could lead to potential differences which eliminate intrinsic safety and render the explosion protection ineffective. These safety barriers must be connected to a potential equalization or grounding system. They are therefore designed so that they can be directly connected to the PE (Protection Earth) terminal via the electrically conductive snap-on mechanism. Figure 22: Connecting a thermocouple via two safety barriers JUMO, FAS 547, Edition Safety barriers

62 17 Safety barriers 17.3 Safety barriers with galvanic isolation For the ex-zone 0, it is recommended to use safety barriers with galvanic isolation. An operational ground connection of intrinsically safe equipment is allowed here. There are no measurement errors due to different ground potentials. Intrinsically safe electrical circuits and evaluation units can have different potentials. Since potential equalization is not required, the installation overhead is reduced. 1 3 U N Ex 2 4 /PA Figure 23: Block diagram of a safety barrier with galvanic isolation JUMO, FAS 547, Edition Safety barriers

63 18 Type testing for intrinsically safe equipment Intrinsically safe equipment must be subjected to type testing. In the associated spark test, it must be proven that the electrical circuits cannot cause an ignition. The category and device group conditions defined according to the standard must be observed. The spark test device in the image is used for this test. For further information see EN annex B. Figure 24: Spark test device Different test mixtures are used depending on the explosion groups. In general, the test gases stated below must be used in volumetric ratio with air under atmospheric pressure. Group Volumetric ratio Gas I 8.3 ± 0.3 % Methane in air IIA 5.25 ± 0.25 % Propane in air IIB 7.8 ± 0.5 % Ethylene in air IIC 21.0 ± 2.0 % Hydrogen in air Table 23: Explosion groups This test is performed in normal operation of the electrical circuit. Depending on the category of the corresponding equipment, the test is also carried out in the presence of one or two errors. The maximum values of the outer capacitance and inductance must be taken into account. In case of DC circuits, at least 400 revolutions (200 per polarity) are carried out and 1000 revolutions in AC circuits. Additionally, a safety factor of 1.5 must be taken into account. Under no circumstances can there be an ignition during the test series. Testing with the spark test apparatus may be missed out if the structure and the electrical values of the equipment are precisely defined so that their safety can be determined based on the explosion limit curves. Intrinsically safe electrical equipment is not subjected to any surface temperature tests if its electrical conditions are sufficiently defined so that its surface temperature can be determined. JUMO, FAS 547, Edition Type testing for intrinsically safe equipment

64 18 Type testing for intrinsically safe equipment 18.1 Ignition limit curves (reference curves) Ignition limit curves serve as a basis for evaluating simple electrical circuits. They can be ohmic, inductive, or capacitive. All three limiting cases (ohmic, inductive, and capacitive) must always be taken into account. The total capacitance and total inductance of the electrical circuit must be limited in order to prevent the occurrence of an ignitable spark. The ignition limit curves are shown in EN annex A. Figure 25: Example of an ignition limit curve with an ohmic electrical circuit JUMO, FAS 547, Edition Type testing for intrinsically safe equipment

65 18 Type testing for intrinsically safe equipment However, they only apply for electrical equipment with a linear current/voltage output. The manufacturer has to specify the limit values for voltage U, current I, power P, capacity C, and inductance L for all equipment or associated equipment, which will ensure intrinsic safety. The specified voltage U is the open-circuit voltage and the specified current I is the short-circuit current. Table 24: Gas group IIC IIB IIA Safety factor x1 x1.5 x1 x1.5 x1 x1.5 Voltage in V Current in ma Admissible short-circuit current according to the voltage and gas group (extract EN ) 18.2 Verification of intrinsic safety Observation 1: The simplest and most commonly encountered situation is the interconnection of intrinsically safe electrical equipment with an associated piece of electrical equipment. The associated equipment is active, the intrinsically safe equipment is passive. Both devices have a linear characteristic line. According to EN standard annex A, the maximum values must be compared. The values can be found either on the nameplates of the equipment, in the operating manual, or the type examination certificates. The capacitances and inductances of the transmitter cable must be included in the comparison. Particular attention should be paid to the heating behavior in normal operation and in the event of an error. Observation 2: If the intrinsically safe equipment and the associated equipment are active, the voltages and currents must be added up. The mathematical proof must be provided using the ignition limit curves as well as the error analysis according to EN standard. Observation 3: If active intrinsically safe equipment is interconnected with non-linear characteristic lines, a calculation procedure must be performed. As the last two examples are less common in practice, proof of intrinsic safety is not discussed further here. In such cases, the relevant regulations must be observed. JUMO, FAS 547, Edition Type testing for intrinsically safe equipment

66 19 Connection examples 28.4 mw no explosive atmosphere ZONE 1 / 2 ZONE 0 Zone boundary 1 ( = 1 mm chrome steel 28.4 mw Resistance thermometer Transmitter Figure 26: RTD temperature probe with transmitter as associated electrical equipment P 750 mw i 750 mw no explosive atmosphere Po 11 mw Exi head transmitter MU ZONE 1 / 2 ZONE 0 Zone boundary 1 ( = 1 mm chrome steel Supply voltage 11 mw Resistance thermometer Supply isolator Figure 27: RTD temperature probe with installed head transmitter and supply isolator as associated electrical equipment 1 Zone separation is not required for Exi "a" (only applies for Exi "b"). JUMO, FAS 547, Edition Connection examples

67 20 JUMO RTD temperature probes according to ATEX RTD temperature probes are components that require special observation in a potentially explosive atmosphere. Great care must be taken, especially when interconnecting RTD temperature probes with other equipment. JUMO has therefore decided to carry out a type examination, according to EU directive 2014/34/EU (ATEX), for different types of RTD temperature probes. Classifying a RTD temperature probe into a temperature class depends on the self-heating characteristics (protection tube constant) and the maximum power of the connected electronics in the event of an error. For example, if a RTD temperature probe is connected to a transmitter, the measuring current of the transmitter generates a negligibly small amount of self-heating of the sensor in normal operation. In the event of an error (disturbed operation), however, a very high current can greatly increase the self-heating through the RTD temperature probe. Non-observance of this self-heating would have catastrophic consequences. The limit value of the temperature class would be exceeded. In measuring series, a protection tube constant was determined for the respective thermometer type. This can be seen on the data sheet for the thermometer. The installer or operator of a system in the potentially explosive area can calculate the maximum admissible measuring temperature at the tip of the thermometer by means of a protection tube constant when interconnecting thermometers with additional equipment. The relationship between the maximum measuring temperature, protection tube constant, and the surface temperature results from the relationship T s T s = T k P o SK Maximum admissible temperature at the tip of the RTD temperature probe (measuring temperature) in degrees Celsius [ C] T k Maximum admissible surface temperature depending on the temperature class in degrees Celsius [ C] P o Power of the intrinsically safe electrical circuit in watts [W] SK Protection tube constant; external heat resistance of the probe in Kelvin per watt [K/W] The influence of inductances and capacitances is negligibly small here. It is therefore not taken into account in the following observations. Example 1: In the event of an error, the maximum power of associated electrical equipment (e.g. a transmitter) is limited to 28.4 mw. A RTD temperature probe is integrated into the intrinsically safe electrical circuits of the equipment. The protective tube constant is 66 K/W (Figure 28). The temperature class is assumed to be T4. This corresponds to a maximal admissible surface temperature of 135 C. According to the EN standard, 5 K must be deducted from the limit values of temperature classes T6, T5, T4, and T3, and 10 K deducted from T1 and T2 for the thermal test. This results in the following calculation: T s = 135 C 5 K W 66 K/W T s = C JUMO, FAS 547, Edition JUMO RTD temperature probes according to ATEX

68 20 JUMO RTD temperature probes according to ATEX The temperature of the measurement medium may exceed C at the tip of the RTD temperature probe. This ensures that, even in the event of an error, the temperature class T4 is not exceeded. Example 2: A transmitter is installed directly into the terminal head of the RTD temperature probe. The complete RTD temperature probe, incl. transmitter, is in a potentially explosive atmosphere (Figure 29). In this case, it is not enough to just determine the maximum admissible temperature of the medium, as in example 1. In addition, the ambient temperature of the transmitter in the connection head must be taken into account. The specific transmitter data (Table 25), the heat radiation of the medium to be measured, the self-heating in the terminal head and the ambient temperature of the terminal head must be taken into account. For example, with JUMO products it results in the following values: JUMO products P o I o U o P i I i U i T6 T5 T4 Supply isolator 547 mw 87.4 ma 25 V Type Transmitter Type Index i = input; o = output 11mW 4.5mA 9.6V 750mW 100mA 30V 55 C 70 C 85 C Table 25: Device-specific data Based on the data, it is already apparent that the maximal values of the supply isolator (P o ; I o ; U o ) are below the limit values of the transmitter (P i ; I i ; U i ). A connection is therefore possible. The JUMO RTD temperature probe used is connected with the intrinsically safe circuit of the transmitter. The maximum output power of the transmitter is P o = 11 mw. Observation of the RTD temperature probe: When assuming a protection tube constant of SK = K/W, a T6 temperature class results in a maximum measuring temperature of T s = 85 C 5 K W K/W T s = 79.3 C Due to the very low power of the transmitter in the case of an error, the temperature of the medium must only be 5.7 K lower that the limit value of the T6 temperature class (85 C). Observation of the terminal head with transmitter: In this example, the ambient temperature of the transmitter T MU [ C] may only be 55 C for the T6 temperature class (Table 25). This temperature specification refers to the immediate environment of the transmitter. The installer or operator of the system has to make sure that the self-heating of the transmitter, the radiated heat of the medium to be measured, and the ambient temperature around the terminal head does not heat the interior of the terminal head to above 55 C. The data sheet for the RTD temperature probe provides assistance here. In case of a power loss of 750 mw of the transmitter, an increase of the internal temperature T V [K] of +10 K must be expected. JUMO, FAS 547, Edition JUMO RTD temperature probes according to ATEX

69 20 JUMO RTD temperature probes according to ATEX In the series of measurements, the increases in the temperature inside the head caused by radiant heat T A [K] were determined under worst-case conditions. With an RTD temperature probe with an extension tube length of 130 mm and a medium temperature of 300 C, the increase is 18 K. A linear conversion to other lengths and temperatures is possible. From our example, it is assumed that the temperature of the medium to be measured must not exceed 79.3 C, this results in, linearly converted, an increase in the internal temperature of around +5 K due to the radiant heat T A [K]. This results in an admissible ambient temperature U T [ C] (head external temperature) of U T = T MU T V T A U T = 55 C 10 K 5 K U T = 40 C Note: With category 1 devices (use in Zone 0), and with RTD temperature probes, make sure that, in the event of a fault, the surface temperature of these devices does not exceed 80% of the ignition temperature [ C] of the flammable gases or liquids used (EN 1127)! Ex area outside Ex area P = 28.4 mw o Temperature class T4 =^ 135 C Protection tube constant 66 C/W Resistance thermometer Transmitter (associated equipment) Supply voltage Figure 28: RTD temperature probe with associated equipment This configuration results in a heating of 28.4 mw x 66 K/W = 1.88 K JUMO, FAS 547, Edition JUMO RTD temperature probes according to ATEX

70 20 JUMO RTD temperature probes according to ATEX Figure 29: RTD temperature probes with head transmitter This configuration results in heating of 11 mw x K/W = 0.73 K JUMO, FAS 547, Edition JUMO RTD temperature probes according to ATEX

71 21 Standards and bibliography EN standard VDE standard Title EN Explosive atmospheres - Explosion prevention and protection Part 1: Basic concepts and methodology EN DIN EN Non-electrical equipment for use in potentially explosive atmospheres - Part 2: Protection by flow restricting enclosure "fr" EN DIN EN Non-electrical equipment for use in potentially explosive atmospheres - Part 3: Protection by flameproof enclosure "d" EN VDE 0170/ Electrical apparatus for use in the presence of combustible dust Part 2-1: Test methods; methods for determining the minimum ignition temperatures of dust EN VDE 01701/ Group 1, category M1 equipment intended to remain functional in atmospheres endangered by firedamp and/or coal dust EN VDE Safety equipment required for the safe functioning of equipment with respect to explosion risks EN VDE Explosive atmospheres Part 0: Equipment - General requirements EN VDE Explosive atmospheres Part 1: Equipment protection by flameproof enclosures "d" EN VDE Electrical apparatus for explosive gas atmospheres Part 2: Pressurized enclosures "p" EN VDE Explosive atmospheres Part 5: Equipment protection by powder filling "q" EN VDE Explosive atmospheres Part 6: Equipment protection by oil immersion "o" EN VDE Explosive atmospheres Part 7: Equipment protection by increased safety "e" EN VDE Explosive atmospheres Part 10-1: Classification of areas - Explosive gas atmospheres EN VDE Explosive atmospheres Part 10-2: Classification of areas - Explosive dust atmospheres EN VDE Explosive atmospheres Part 11: Equipment protection by intrinsic safety "i" EN VDE Explosive atmospheres Part 14: Electrical installations design, selection and erection EN VDE Electrical apparatus for explosive gas atmospheres Part 15: Construction, test and marking of type of protection "n" electrical apparatus EN VDE Explosive atmospheres Part 17: Electrical installations inspection and maintenance JUMO, FAS 547, Edition Standards and bibliography

72 21 Standards and bibliography EN standard VDE standard Title EN VDE Electrical apparatus for explosive gas atmospheres Part 18: Construction, test and marking of type of protection encapsulation "m" electrical apparatus EN VDE Explosive atmospheres - Material characteristics for gas and vapour classification - test methods and data EN VDE 0170/ Electrical apparatus for explosive gas atmospheres Part 25: Intrinsically safe systems EN VDE Explosive atmospheres Part 26: Equipment with equipment protection level (EPL) Ga EN VDE Explosive atmospheres Part 28: Protection of equipment and transmission systems using optical radiation EN VDE Degrees of protection provided by enclosures (IP Code) EN ISO DIN EN ISO Non-electrical equipment for use in potentially explosive atmospheres - Part 1: Basic method and requirements EN ISO DIN EN ISO Non-electrical equipment for explosive atmospheres - Nonelectrical type of protection constructional safety "c", control of ignition sources "b", liquid immersion "k" Table 26: Standards JUMO, FAS 547, Edition Standards and bibliography

73 21 Standards and bibliography Deutsche Gesetzliche Unfallversicherung (DGUV) (English: German statutory accident insurance) DGUV Explosionsschutzregelung (English: explosion protection regulation) Technische Regeln für Betriebssicherheit (TRBS) (English: Technical regulations for operational safety) TRBS 1201 Prüfung von Arbeitsmittel und überwachungsbedürftigen Anlagen (English: Checking of work material and plants requiring surveillance) TRBS 2152 onwards Gefährlich explosionsfähige Atmospäre (English: Dangerous potentially explosive atmosphere) Directive 2014/34/EU of the European Parliament and of the Council from February 23, 2014 Regulation for electrical plants in potentially explosive rooms (ElexV) Directive for avoiding dangers due to potentially explosive atmospheres with a collection of examples - explosion protection directive (Rx-RL) Technical paper by L. Börner: Explosionsschutz nach Europa-Norm Rechtsunsicherheit vermeiden; (English: Explosion protection according to European standards - avoiding legal uncertainty) Hütig publishing house JUMO technical paper by J. Goldmann: Theorie und Anwendung von (Ex)i-Zener-Barrieren (English: Theory and application of (Ex)i zener barriers Technical paper by Dr. N. Müller: Lagerung von brennbaren Flüssigkeiten Vorschriften geändert; (English: Storage of combustible liquids - regulations changed) Chemie Umwelt Technik Technical paper by Dipl.-Ing. R. Thater: Beliebige Oberflächentemperatur (English: Any surface temperature) Technical paper by Bürkert GmbH: Explosionsschutz nach Europanorm (English: Explosion protection according to European standards); Chemie-Technik Technical paper by Dipl.-Ing. W. Bansemir and Dipl.-Ing. W. D. Dose: Grundlagen für den Ex-Schutz in der Praxis (English: Basics for ex-protection in practice); Chemie-Technik Technical paper by Dipl.-Ing. M. Winkelmann: Eigensichere MSR-Anlagen (English: Intrinsically safe M&C systems) Technical paper by Dipl.-Ing. Pulewka: Zündende Ideen (English: Exciting ideas); Chemie-Technik Technical paper by A. Schischek: Die richtige Lösung der MSR-Technik in der Ex-Zone (English: The right solution for M&C technology in the ex-zone); Chemie-Technik Prof. Dr.-Ing. H. Wehinger: Explosionsschutz elektrischer Anlagen (English: Explosion protection for electrical systems); expert-verlag EN/VDE standards; Beuth publishing house, Berlin Para. 16 to 18 Ex-zone Principles of explosion protection with a collection of examples; Suva - Schweizerische Unfallversicherungsanstalt (English: Swiss accident insurance institution) JUMO, FAS 547, Edition Standards and bibliography

74 21 Standards and bibliography Para. 2 and 25 Fachstelle für Sicherheit elektrischer Betriebsmittel BVS (English: Expert body for the safety of electrical equipment) JUMO, FAS 547, Edition Standards and bibliography

75 Index A Ambient temperature 18 Areas, danger of explosion 8 Associated electrical equipment 52 Atmosphere, potentially explosive 8 C Category 18, 43, 48 CENELEC 12 Certificate of conformity 13 Clearances 55 Combustion point 8 Conductor tracks 54 Creepage distances 55 D DakkS 13 Designated body 15 Designated test facilities 13 Device group 43 Devices and protective systems 15 Distances in potting 55 DKE 12 Dust layer thickness 27 Dusty atmosphere with conductive dusts 27 E Electrical equipment 13, 26 Electrostatics 9 EPL 19, 31 EU declaration of Conformity 21 EU declaration of conformity 13 EU directive 2014/34/EU 13 EU Directive 1999/92/EC 10 EU type examination 13 Explosion 7 Explosion group 18 Explosion groups 34 Explosion protection 18 Explosion protection, primary 24 Explosion protection, secondary 25 Explosionsgruppe 16 Explosive gas areas 19 F Flameproof enclosure 28 Flammable substance 19 Flammable substances 7 G Galvanic isolation 60 German Industrial Safety Regulation (BetrSichV) 11 German Product Safety Act (ProdSG) 11 Ground 55 H Hazardous quantity 8 Hybrid mixture 9 I Identification marking 18 Ignition energy 34 Ignition limit curve 62 Ignition protection level 38 Ignition protection type 18 "ia"/"ib" 33 Ignition source 7 Ignition temperature dust 9 gas 8 of dust 9 of gas atmosphere 8 Increased safety 28 Intrinsic safety 35, 51 Intrinsically safe electrical equipment 52 L Legal principles 12 M Maximum experimental safe gap 34 MESG 34 MIC 35 Mines exposed to firedamp 19 73

76 Index Minimum ignition current 35 Mounting 53 N Notified body 13 O Obligations of manufacturers and operators 23 Oil immersion 28, 69 Operation without faults 52 P Placement of electrical equipment onto the market 13 placing onto market 13 Plug connector 53 Potentially explosive atmosphere, areas 8 Powder filling 28 Pressurized apparatus 28 Production 14 Protection level 19 Protective measures 8, 24 Protective pipe constant 65 Temperature class 18 Temperature classes Temperature limits for dust 47 Temperaturklasse Oberflächentemperatur 16 Terminals 53 Testing procedure 13 Type examination 61 Type examination certificate 15, 18 Z Zener diodes 59 Zones Categories 48 Division 39 Dust 46 Gas 44 Q Quality assurance 14 Quality assurance system 18 Quantity, hazardous 8 R RTD temperature probe 65 S Safety barrier 58 Safety barriers 58 Selection criteria 26 Smoldering temperature of dust 9 Standards 69 Surface temperature 27, 36 T 74

77 Informative material from JUMO for beginners and those with some practical experience Know-how is not just needed to create JUMO products, but also for their later application. That is why we offer several publications on aspects of measurement and control engineering for our users. The publications are intended to provide step-by-step familiarization with a wide range of applications, for both beginners and those with some practical experience. They primarily illustrate general topics with JUMO-specific applications to some extent. In addition to JUMO technical literature and our new software downloads we also offer the possibility to order our brochures and catalogs online. Electrical Temperature Measurement with thermocouples and resistance thermometers Matthias Nau FAS 146 Sales no.: ISBN: X Free of charge Control Engineering Basic principles and tips for practitioners Manfred Schleicher FAS 525 Sales no.: ISBN: Free of charge Explosion Protection in Europe Electrical equipment fundamentals, guidelines, standards Dieter Herrmann FAS 547 Sales no.: ISBN: X Free of charge Information on high-purity water Reinhard Manns FAS 614 Sales no.: Free of charge Information on redox voltage measurement Ulrich Braun FAS 615 Sales no.: Free of charge Information on the amperometric measurement of free chlorine, chlorine dioxide and ozone in water Dr. Jürgen Schleicher FAS 619 Sales no.: Free of charge SCR Power Controllers Basic principles and tips for professionals Manfred Schleicher, Winfried Schneider FAS 620 Sales no.: ISBN: Free of charge Information on ph measurement Matthias Kremer FAS 622 Sales no.: Free of charge

78 Informative material from JUMO for beginners and those with some practical experience Information on Conductivity Measurement Reinhard Manns FAS 624 Sales no.: Free of charge Error Analysis of a Temperature Measurement System with worked examples Gerd Scheller, Stefan Krummeck FAS 625 Sales no.: ISBN-13: Free of charge Information on the Measurement of Hydrogen Peroxide and Peracetic Acid Dr. Jürgen Schleicher FAS 628 Sales no.: Free of charge Functional Safety Safety Integrity Level Dr. Thomas Reus, Matthias Garbsch FAS 630 Sales no.: Free of charge Information on measuring ammonia in water Dr. Jürgen Schleicher FAS 631 Sales no.: Free of charge Please visit our website and familiarize yourselves with the wide variety of JUMO products for different application fields. Our website provides you with more details and information concerning the contact persons for your requirements, questions, and orders.

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