Guide to application of the ATEX 2014/34/UE directive - APPLICATION OF DIRECTIVE 2014/34/EU ALONGSIDE OTHERS Directives

APPLICATION OF DIRECTIVE 2014/34/EU ALONGSIDE OTHERS THAT MAY APPLY

In principle, if a product is within the scope of other Union harmonisation legislation (directives, regulations) at the same time, all directives have to be applied in parallel to fulfil the provisions of each directive.

In this context it is important to note that a notified body is only allowed to cover aspects related to two or more directives if the body is notified under all directives with an appropriate scope.

§ 231  Electromagnetic Compatibility Directive 2014/30/EU (EMC)

In the case of the Directive relating to Electromagnetic Compatibility 2014/30/EU (EMC), the ATEX Directive 2014/34/EU has to be applied to fulfil the requirements concerning “explosive atmospheres” safety requirements. The EMC Directive must also be applied so as to ensure that the product does not cause electromagnetic disturbance and that its normal operation is not affected by such disturbances. There will be some applications, where the "normal" level for electromagnetic immunity provided by Directive 2004/108/EC might not be sufficient for granting the necessary immunity level for safe performance under the scope of Directive 2014/34/EU. In this case the manufacturer is required to specify the electromagnetic immunity achieved by his products according to Annex II 1.2.7 to Directive 2014/34/EU. For example, protective systems where the performance of data acquisition and data transmission may have direct influence on explosion safety.

The Electromagnetic Compatibility Directive 2014/30/EU, replacing the previous Directive 2004/108/EC, is applicable from 20 April 2016.

§ 232  Low Voltage Directive 2014/35/EU (LVD)

Products for use in potentially explosive atmospheres are explicitly excluded from the scope of the Low Voltage Directive 2014/35/EU (LVD). Therefore "Low Voltage essential objectives" have to be covered by the Directive 2014/34/EU (see Annex II 1.2.7). The standards published in the Official Journal of the European Union with reference to Directive 2006/95/EC may be listed in the EU declaration of conformity to fulfil the requirements 1.2.7 of Annex II to Directive 2014/34/EU. Not excluded from the scope of the LVD are the safety, controlling and regulating devices mentioned in Article 1(1)(b) of Directive 2014/34/EU which are intended for use outside potentially explosive atmospheres but required for or contributing to the safe functioning of equipment and protective systems. In such cases both Directives shall be applied.

Note: These requirements are reproduced in the European harmonised standards for electrical equipment intended for use in potentially explosive atmospheres. To align with the respective conformity assessment regimes of ATEX and LVD, the harmonised standards do not require that a notified body issuing an EU-type examination certificate for ATEX should verify that these requirements have been met but that the manufacturer shall declare that they have been met. This is reflected in the contents of the declaration of conformity mentioned above.

The Low Voltage Directive 2014/35/EU, replacing the previous Directive 2006/95/EC, is applicable from 20 April 2016.

§ 233  Machinery Directive 2006/42/EC (MD)

The relation between Directive 2014/34/EU and the Machinery Directive 2006/42/EC is different. The Directive 2014/34/EU, which is a "specific Directive" within the meaning of Article 3 of the Machinery Directive, contains very specific and detailed requirements to avoid hazards due to potentially explosive atmospheres, while the Machinery Directive itself contains only very general requirements against explosion hazards (Annex I, 1.5.7 MD).

With regard to explosion protection in a potentially explosive atmosphere, Directive 2014/34/EU takes precedence and has to be applied. So equipment that complies with ATEX, and which is also a machine can be assumed to comply with the specific essential safety requirements concerning ignition risk with respect to explosive atmospheres in the Machinery Directive. For other relevant risks concerning machines, the requirements of the Machinery Directive also have to be applied.

See also section § 35 on place of intended use.

§ 234  Transport of dangerous goods by road Directives 94/55/EC and 98/91/EC (ADR)

In order to avoid possible overlapping with Directives 94/55/EC and 98/91/EC on transport of dangerous goods by road most means of transport have been excluded from the scope of Directive 2014/34/EU (Article 1(2)(f)). Generally, those vehicles still included in Directive 2014/34/EU do not leave the user's premises. Typical examples are means of transport on rails used in "gassy" mines, forklift trucks and other mobile machinery where the internal combustion engine, braking systems and electrical circuits may be potential sources of ignition.

It is possible for both Directives to be applied in parallel. For example, where the manufacturer designs and constructs a means of transportation intended for transporting dangerous (in this case flammable) goods on public roads as well as for use in areas where explosive atmospheres may exist.

The criteria for application of Directive 2014/34/EU are that the vehicle would need to:

  • be defined as an equipment, a protective system or safety device according to Article 1(1) of the Directive;
  • have its own potential source of ignition;
  • be intended for use in a potentially explosive atmosphere (unless it is a safety device as defined under Article 1(1)(b) of Directive 2014/34/EU).

In order to determine under which intended conditions both Directives will apply the exclusion at Article 1(2)(f) of Directive 2014/34/EU needs to be considered.

This exclusion explicitly determines that "means of transport" except those "intended for use in a potentially explosive atmosphere shall not be excluded".

The definition of "means of transport" is given further detail at Article 2 of Directive 98/91/EC and, in broad terms, is interpreted to be an activity on a public highway or space including unloading and loading operations.

The ATEX Committee therefore considered that, as described in the Commission guidance, a vehicle under the scope of Directive 98/91/EC might also be covered by the ATEX Directive 2014/34/EU.

Where such a vehicle is intended for use in a potentially explosive atmosphere both Directives will apply. However, this does not include where such environments are likely to occur solely as a result of loading and unloading operations as described in 98/91/EC. An example of this is a road tanker transporting petrol when the loading/unloading site is such that it is not initially considered to have a potentially explosive atmosphere because of its location with respect to the storage facility. As noted above, if this environment becomes potentially explosive because of the loading/unloading operation, only the requirements of Directive 98/91/EC need be applied.

In addition, it was agreed that the conformity assessment and technical requirements of 94/55/EC as further defined by 98/91/EC may not fully align with those required for compliance to Directive 2014/34/EU.

In this context the question arose whether manufacturers of internal monitoring or other devices attached to or inside a vehicle such as a petrol tanker have to apply the ATEX Directive 2014/34/EU and to affix CE marking. The following has been concluded:

1. Based on Article 75 of the EC Treaty (currently Article 95 TFEU) and transposing the ADR, Directive 94/55/EC fully harmonises rules for the safe transport of dangerous goods by road.

2. Additionally, based on Article 95 of the EC Treaty (currently Article 114 TFEU), Directive 98/91/EC provides for full harmonisation regarding technical requirements for the following categories of vehicles intended for the transport of dangerous goods by road as follows:

  • Category N: Motor vehicles having at least four wheels when the maximum weight exceeds 3.75 metric tons, or having three wheels when the maximum weight exceeds 1 metric ton, and used for the carriage of goods.
  • Category O: Trailers (including semi-trailers).

According to Article 4, if the requirements of the Annexes of this Directive are fulfilled for the completed vehicle, Member States may not refuse to grant EU-type approval or to grant national-type approval, or prohibit the registration, sale or entry into service of those vehicles on grounds relating to the transport of dangerous goods.

3. Directive 98/91/EC contains, by reference to Directive 94/55/EC, requirements covering both electrical (e.g. wiring, batteries) and non-electrical equipment (e.g. heat protection of engine, combustion heaters) of vehicles designed for the carriage of dangerous goods, which may contribute towards the formation of explosive atmospheres.

4. Provided that:

- Such vehicles are not intended for use in a potentially explosive atmosphere other than that caused temporarily by loading or unloading.

  • The goods, which shall be transported, are substances and articles as defined in Article 2 of Directive 94/55/EC.
  • The exemptions of Annex A, paragraph 1.1.3, of Directive 94/55/EC and the ADR agreement are not pertinent.

Under these circumstances the exclusion at Article 1(2)(f) of Directive 2014/34/EU applies to the WHOLE of the vehicle including ALL associated equipment necessary for the carriage of dangerous goods (e.g. "breather valves" of manhole covers, vehicle tracking systems).

In all other cases, the ATEX Directive 2014/34/EU may apply.

Note 1: At some sites tankers may have to access a zone (e.g. zone 1). In this case users responsible for that site may demand the supplier to use tankers with ATEX compliant products.

Note 2: Even if the vehicle or parts of it are intended to be permanently used in a potentially explosive atmosphere, devices like "breather valves" of manhole covers normally would not fall within the scope of Directive 2014/34/EU. Normally these devices have no own ignition source, are no safety devices in the sense of ATEX and are normally not provided with a protective system, such as a flame arrester.

§ 235  Personal Protective Equipment Directive 89/686/EEC (PPE)

The equipment covered by the Personal Protective Equipment (PPE) Directive 89/686/EEC is specifically excluded from Directive 2014/34/EU. However, the manufacture of PPE for use in explosive atmospheres is covered by basic health and safety requirement 2.6 in Annex II to the PPE Directive. PPE intended for use in explosive atmospheres must be so designed and manufactured that it cannot be the source of an electric, electrostatic or impact-induced arc or spark likely to cause an explosive mixture to ignite. Following the EHSRs in Directive 2014/34/EU is one way to demonstrate compliance.

Note: a Commission Proposal for a new Regulation on Personal Protective Equipment has been issued on 27 March 2014 and it is currently under discussion at the European Parliament and the Council.

§ 236  Pressure Equipment Directive 2014/68/EU (PED)

The Pressure Equipment Directive (PED) 2014/68/EU is a single market directive similar to Directive 2014/34/EU. Relatively few items of pressure equipment have their own source of ignition. There are a small number of examples of safety accessories which may be autonomous protective systems or, possibly, equipment. Flame arrestors have been judged to be pressure accessories in the sense of the PED. There are no additional requirements for the flame arrester element under the PED. PED specifically excludes from its own scope equipment classified no higher than Category I under Article 9 of PED but inside the scope of ATEX.

The Pressure Equipment Directive deals only with the pressure hazard and does not consider the prevention of and protection against explosions/inflammations, which are not triggered by pressure. In most cases it is presumed that PED equipment does not have an own ignition source when it is properly installed according to the instructions of the manufacturer (including information about maintenance and repair of the connecting devices, e.g. valves, flanges). If such PED equipment shows hot surfaces occurring during operation caused by the temperature of its content solely, it is not applicable to consider this equipment under the ATEX Directive 2014/34/EU.

The Pressure Equipment Directive 2014/68/EU, replacing the previous Directive 97/23/EC, is applicable from 19 July 2016.

§ 237  Simple Pressure Vessels Directive 2014/29/EU (SPVD)

The Simple Pressure Vessel Directive 2014/29/EU applies to a limited range of equipment for holding air or nitrogen under pressure. ATEX equipment may incorporate a simple pressure vessel in an assembly, but it is considered that there are relatively few occasions when both Directives will apply to the same product.

The Simple Pressure Vessels Directive 2014/29/EU, replacing the previous Directive 97/23/EC, is applicable from 20 April 2016.

§ 238  Gas Appliances Directive 2009/142/EC (GAD)

The Gas Appliances Directive (GAD) 2009/142/EC applies to equipment for domestic and non-commercial use but does not apply to equipment designed for industrial processes. Most equipment within scope of GAD is capable of igniting a surrounding explosive atmosphere and cannot comply with ATEX.

It should also be noted the exclusion contained in Article 1(2)(c)) of Directive 2014/34/EU regarding “accidental leak of fuel gas”.

The question has been raised as to whether this implicitly conveys the meaning that such equipment, where the leakage is not fuel gas, are included in the scope of the ATEX Directive. It was agreed that, as a general rule, such types of equipment are excluded from the Directive as they are not intended for use in a potentially explosive atmosphere.

Note: a Commission Proposal for a new Regulation on appliances burning gaseous fuels has been issued on 12 May 2014 and it is currently under discussion at the European Parliament and the Council.

§ 239  Construction Products Regulation No 305/2011 (CPR)

The Construction Products Regulation (CPR) No 305/2011 replaced the Construction Product Directive 89/106/EEC (CPD) as by 1 July 2013. Concerning the relationship with the ATEX Directive 2014/34/EC, it was identified that (in a few areas) the scopes of both legislations could overlap. The areas already identified where:

- explosion protection systems and fire suppression systems using the same media;

- both areas are using common hardware for distribution systems such as pipes, pipe hangers, nozzles, etc.

In general, it can be stated that in cases of doubt the Construction Products Regulation is applicable if the subject under discussion is fixed to a building and becomes then a part of the building or if it can be seen as a building itself (e.g. a silo). In such instances the CPR and the ATEX Directive 2014/34/EU apply in parallel. Compliance with the EHSRs of Directive 2014/34/EU will in general show compliance with the EHSRs of the CPR regarding ignition hazards.

§ 240  Marine Equipment Directive 96/98/EC (MED)

The Marine Equipment Directive (MED) 96/98/EC is not a "New Approach" Directive, as it is based on the principles of the "Global Approach" and does not provide for CE marking. Directive 2014/34/EU specifically excludes from its scope "seagoing vessels and mobile offshore units together with equipment on board such vessels or units", and equipment for use on board a ship is subject only to the MED directive, excluding all others. Nevertheless, the constructional requirements for explosion-protected equipment at sea are generally the same as onshore: this is illustrated by the reference of the MED to the same or very similar standards, as harmonised under the ATEX Directive. In fact, certain products (such as gas detection equipment) are used offshore and onshore, thus requiring certification per the ATEX Directive and/or by the MED, according to their intended use.

 

 

APPLICATION OF DIRECTIVE 2014/34/EU TO SPECIFIC EQUIPMENT

As already indicated (see section § 34), in some specific circumstances clarification is needed, in order to decide whether a certain product falls within the scope of Directive 2014/34/EU or not. This will be clarified using different examples concerning the application of the ATEX Directive to specific equipment, on the basis of "Consideration Papers" and other guidance documents discussed and approved by the ATEX Committee.

Also, the "Borderline list - ATEX products" (see pages 225-228) is useful to clarify the situation of a number of products (equipment, protective systems, components, safety controlling or regulating devices, and others) with respect to the ATEX Directive 2006/42/EU.

§ 241  Inerting systems

When looking for the application of Directive 2014/34/EU to inerting systems one has to consider three different cases:

a) Preventing an explosive atmosphere

Inerting systems are aimed at reducing or completely preventing the existence of an explosive atmosphere in specific areas. Inerting systems are not, however, intended to stop or restrain incipient explosions; hence they are not protective systems within the meaning of Directive 2014/34/EU. The goal of inerting systems is different from those of explosion suppression systems, which may sometimes have similar parts, but are aimed at restraining an incipient explosion.

In broad terms: inerting systems used during operation of plants etc. are normally not in scope of Directive 2014/34/EU.

Example: The intended effect of an inerting system applied to inert a tank can only be assessed after knowing all operational parameters of the volume to be inerted. This assessment and the functional aspects of such systems are not covered by Directive 2014/34/EU but a duty to be considered by the user and has to be laid down e.g. in the explosion protection document under the scope of Directive 1999/92/EC and its national transpositions.

b) Inerting systems as equipment

An inerting system may (in part) also consist of parts which are intended for use within an explosive atmosphere and which have a potential ignition source of their own. These parts come – individually or possibly combined – under the scope of Directive 2014/34/EU as "equipment". Also in this case their function of preventing an explosive atmosphere by inerting is not to be assessed within the meaning of this Directive.

c) Inerting system as part of the ignition protection concept

In some cases, such systems may be part of the ignition protection concept of “explosion protected" equipment to fulfil the requirements of Annex II to Directive 2014/34/EU, i.e. if they work as a means to protect potential ignition sources of the equipment from coming into contact with an existing potentially explosive atmosphere. This equipment, including its inerting system, comes as part of the equipment under the scope of Directive 2014/34/EU. This inerting system is not a protective system according to Article 1(1)(a). Its parts may be safety, controlling and regulating devices according to Article 1(1)(b) of Directive 2014/34/EU when separately placed on the market.

In broad terms: Directive 2014/34/EU applies to an inerting system, if this system is – or is intended to be – integrated into the ignition protection concept of the equipment and thus serves to avoid ignition sources of the equipment.

Example: Where the manufacturer of equipment intended for use in potentially explosive atmosphere wants to protect the ignition sources of this equipment, he may use the type of protection "pressurisation" according to EN 60079-2. This type of protection may include the use of inert gases as protective gases. In this case the inerting system is part of the equipment and as such within the scope of Directive 2014/34/EU. The following case may occur in practice: equipment according to Article 1 of Directive 2014/34/EU contains an enclosure or a vessel containing sources of ignition. In order to prevent an explosive atmosphere from coming into contact with the ignition sources, an inerting system, which has been assessed in accordance with Directive 2014/34/EU as a safety device, can be applied to this equipment.

§ 242  Paint spray booths

These products are an enclosed area, where an operator may work inside or outside, and may be described as a "simple box". The "box", with no ignition source and not intended for use in a potentially explosive atmosphere, does not fall within the scope of the ATEX Directive 2014/34/EU.

Under operating conditions a potentially explosive atmosphere is created and the enclosed area, openings and recovery systems are normally assessed with regard to the explosion risk. The equipment, protective systems and components intended for use in this assessed potentially explosive atmosphere including safety and controlling devices outside, but contributing to their safe functioning, are within the scope of Directive 2014/34/EU.

In summary, paint spray booths, as an integral whole, do not fall under scope of the ATEX Directive 2014/34/EU and as such cannot be affixed with the special marking for explosion protection and other marking detailed at Annex II, EHSR 1.0. of the Directive.

§ 243  Filter units and vented silo bins

The question arises, how should the Directive be applied to filter units and vented silo bins?

Most filters and silo bins will have an explosive dust cloud inside at some point during normal operation.

The inside may be areas in which an explosive atmosphere caused by air/dust mixtures are present continuously, for long periods or frequently, or areas in which such an atmosphere is likely to occur, depending on the operating conditions.

Many filters and silos are located in the open air, or in a room in a building which does not need to be classified as hazardous.

With the exception of 5)a) and 7) the description below of different cases assumes that filters and silos themselves will not be a source of dust release that would give rise to a potentially explosive atmosphere in the surrounding area.

This description also considers that many apparatuses with filters inside are fitted with explosion protection devices, such as vent panels, doors or suppression equipment.

1) The filter or the silo bin has no moving parts or electrical equipment on the inside, and is located in a non-hazardous area.

Conclusion: These filters or silos are not in scope of the Directive 2014/34/EU.

Electrostatic hazards may exist from insulating surfaces inside the filter, from the filter elements or from cone discharges in silos. This risk depends for example on the properties of the dust being collected, and other operating conditions. But any electrostatic risks are not considered as giving the filter or silos its own potential source of ignition, so these filters or silos do not fulfil the definition of equipment in Article 1(3)a.

Remark: These filters or silos do not fulfil the other criteria of the definition.

The electrostatic risks can be covered by other directives, for example the Machinery Directive when the filter is part of a machine. In this case the manufacturer of the machine is responsible to avoid this risk according to the regulations of the Machinery Directive 2006/42/EC. In all cases these risks must be controlled by the user under Directive 1999/92/EC. The electrostatic risks are covered in the standard EN 13463-1 Non-electrical equipment for use in potentially explosive atmospheres - Part 1: Basic method and requirements.

2) The filter has moving parts inside that can be considered as mechanical equipment, such as a bag shaking mechanism, or a screw feeder to remove collected dust. The whole filter is located in a non-hazardous area.

Conclusion: The manufacturer must assess whether the moving parts create its own potential source of ignition. If the moving parts do not create any potential source of ignition, perhaps because they have low power, or move very slowly, the situation is the same as case 1, and the filter is not in scope of the Directive.

Remark: Low power in this sense is not given, when for example the power source is strong and only the power inside the equipment is reduced by protection methods in order to avoid an ignition risk. There is a similar situation in case of the electrical type of protection the "intrinsic safety".

If the mechanical equipment on the inside does create an ignition risk, this equipment (as part of the complete apparatus) must comply with the Directive 2006/42/EU (see section § 35 on place of intended use).

If inside the filter an explosive atmosphere caused by air/dust mixtures is present continuously, for long periods or frequently, according to Annex I for the equipment inside, conformity with category 1 should be reached. But this will in respect of the state of the art not always be possible. In these cases according to:

- Annex II A, technological knowledge must be taken into account,

and

- Annex II 1.0.1, the principles of integrated explosion safety must be applied.

That means when it is not possible to prevent the ignition source sufficiently – according to the "state of the art" – to reach category 1, category 2 can be sufficient when the manufacturer takes additional measures "to halt it immediately and/or to limit the range of explosion flames and explosion pressures to a sufficient level of safety" (see Annex II 1.0.1 indent 3). It is in the responsibility of the manufacturer to take this decision.

The explosion vent can be seen as an example of integrated explosion safety as described under Annex II 1.0.1.

In this case, and if the complete apparatus (filter with explosion vent panel or doors) is produced and integrated by the same manufacturer, not only the mechanical but all equipment inside falls under the scope of Directive 2014/34/EU. Consequently the manufacturer takes the following measures:

- preventing sufficiently the ignition source inside (according to the "state of the art");

- selecting an appropriate protective system in order to limit the range of explosion flames and pressure;

- designing the filter in such a way that it can withstand an internal explosion without rupturing (design for the reduced explosion pressure in conjunction with explosion pressure relief or explosion suppression).

3) The complete filter or the silo bin has electrical equipment inside. In filters those electrical equipment may be a pressure switch, or level switch on the container that collects the dust, in silos level indicators are widely used.

Conclusion: This electrical equipment is equipment in the sense of Article 1.1 of the Directive 2014/34/EU and therefore must comply with this Directive.

4) The silo bin or the complete apparatus with the filter is fitted by the manufacturer with explosion vent panels or doors, supplied by another manufacturer.

Conclusion: These panels or doors are 'protective systems' in the sense of the Directive 2014/34/EU and the manufacturer of these systems has to apply the directive when placing this as an autonomous system on the market. That means the procedure set out in Article 13(2) has to be applied and they must be CE and ex marked. Selecting the correct panel or door (for example: size, quality, function) depends on the application and has to be done by the manufacturer of the apparatus.

5) The silo bin or the complete apparatus with the filter is fitted with explosion vent panels or doors produced and integrated into the filter or silo by the filter/silo manufacturer themselves.

Conclusion:

For filters we have to distinguish two cases:

a) The complete apparatus is in the scope of the Directive 2014/34/EU.

b) The complete apparatus is not in the scope of the Directive 2014/34/EU.

For silos, generally case b) is applicable.

Case a)

These are not autonomous protective systems according to Article 2(2) because they are placed on the market as a part of an equipment in the sense of Article 1(1) and not separately. Therefore Article 13(2) has not to be applied. The protective system alone is not in the scope of the Directive but the whole equipment. That means the conformity procedure of the equipment includes the protective system.

However, if another manufacturer sells complete replacement vent panels or doors as spare parts, these are autonomous protective systems, separately placed on the market and then he must apply the Directive 2014/34/EU. That means they must for example be tested, CE and ex marked in the same way as complete panels or doors separately placed on the market from other manufacturers.

Case b)

These complete apparatus or explosion vent panels or doors are autonomous protective systems according to Article 2(2) because they are separately placed on the marked in the sense of the directive and therefore Article 13(2) has to be applied. That is because they are not placed on the market as a part of an equipment in the sense of Article 1(1).

Remark for filters: In case 4 or 5, the manufacturer in any case carries responsibility for ensuring that the body of the filter will not fail in the event of an explosion, even though it is not covered by specific EU legislation. Users should ask the manufacturers how they can be sure that the filter complies with the safety requirements of the Work Equipment Directive 2009/104/EC (that repealed the Directive 89/655/EC amended by 95/63/EC and 2001/45/EC); especially Annex I, 2.7.

Remark for silos: Even protective systems such as vent areas which are integrated in the cell ceiling of silos or inserted lightweight constructions are protective systems for the purpose of Directive 2014/34/EU and must be placed separately on the market as autonomous protective systems and must therefore be treated as such with regard to assessment of conformity and marking.

6) A – normally small – apparatus with only a filter sock, plastic collection bag and fan, but no metal enclosure.

Conclusion: If during the intended use a dangerous explosion pressure cannot be formed in such a small apparatus when a dust cloud inside the filter is ignited, the inside is not to be classified as a hazardous area and the equipment used inside is not in the scope of the Directive 2014/34/EU.

This is the case with some filters used for collecting wood dust and wood-waste.

7) The silo or an apparatus with a filter is intended to be installed in an area, in which air/dust mixtures are unlikely to occur or, if they do occur, are likely to do so only infrequently and for a short period only.

Conclusion: In respect of the complete apparatus the Directive 2014/34/EU is only relevant for the manufacturer, if it is equipment in the sense of this Directive. To find out if the whole apparatus is such equipment, the manufacturer of this apparatus for example must examine if it creates any possible sources of ignition, which can ignite an explosive atmosphere on the outside. When this can happen, he has to apply the Directive 2014/34/EU.

The apparatus must in this case conform to category 3.

Remark: Equipment of this type may be needed if there are for example sources of dust release from other equipment nearby.

As silos have no own possible ignition source, which can ignite an explosive atmosphere on the outside, they will not conform to category 3.

General remark for autonomous protective systems:

Measures for the indirect explosion pressure venting at buildings, like for example windows, walls of lightweight construction or similar, do not fall within the scope of Directive 2014/34/EU. The employer/operator himself is responsible to implement such measures. In doing so, priority shall be given to the requirements according to the building regulations.

§ 244  Gas turbines

1. It was accepted by all concerned that:

- Gas turbines on their own are not normally placed on the market as a single functional unit but are generally incorporated with other machinery before they can function, and will only function as intended once they are properly installed.

- Since 30 June 2003, manufacturers and users of gas turbines need to comply, in addition to the Machinery Directive, as appropriate with the requirements of both ATEX Directives 94/9/EC (since 20 April 2016, 2014/34/EU) and 1999/92/EC respectively – relating to design and manufacture of such equipment and the health and safety of workers potentially at risk of explosive atmospheres.

- Gas turbine fuel supplies may give rise to a potentially explosive atmosphere in the vicinity of the turbine. Additionally, other sources of a potentially explosive atmosphere may also exist, e.g. lubricating oils. Equipment in category 3 of equipment-group II would usually be required in such areas.

- In normal circumstances, a gas turbine could have hot surfaces above the auto ignition temperature of the fluids used. Operation under fault conditions may increase surface temperatures.

- A gas turbine which has surface temperatures that can lead to the ignition of a potentially explosive atmosphere cannot comply with the relevant provisions of Directive 2014/34/EU. In such circumstances additional measures are required.

2. It should be noted that in all instances of the following guidance the general concepts described for "Place of intended use" (see section § 35) and for "Interface to different potentially explosive atmospheres" (see section § 36) will apply (e.g. ATEX compliant equipment must be used, where applicable, inside machinery).

- Although manufacturers must, to the state of the art, eliminate or control sources of ignition, it may not be technically possible to reduce the temperature of all hot surfaces to comply with the essential health and safety requirements of the ATEX Directive 2014/34/EU.

- A number of alternatives are available for selection as a basis for safety, e.g. limitation of the volume of the explosive atmosphere by dilution ventilation, explosion relief, explosion suppression or a combination of these techniques.

- A supplier (this may be the turbine manufacturer, packager, installer, final supplier, etc. and in some cases the end user) delivering gas turbine machinery and associated safety devices is responsible for risk assessment and implementation of the chosen basis of safety under Directive 2014/34/EU. Irrespective of the chosen basis of safety there is the potential for an explosive atmosphere to arise near the turbine, and proper consideration should be given to minimising the risk of ignition. The supplier as described above is also responsible for the communication of instructions for safe use and any residual risk to the end user sufficient for the completion of risk assessments under the relevant workplace directives.

- Interested parties should consider the provisions of the ATEX Directive 2014/34/EU and guidance documents with further information on the relevant responsibilities.

3. A gas turbine as a complete machine the ignition sources of which have no interface to a potentially explosive atmosphere outside the enclosure does, however, not fall under scope of the ATEX Directive 2014/34/EU and as such cannot be affixed with the special marking for explosion protection and other marking detailed at Annex II, EHSR 1.0.5. of the Directive.

4. Intended to be used in a potentially explosive atmosphere.

§ 245  Steam turbines

1. It was accepted by all concerned that:

- Steam turbines on their own are not normally placed on the market as a single functional unit but are generally incorporated with other machinery before they can function, and will only function as intended once they are properly installed.

- Since 30 June 2003, manufacturers and users of steam turbines placed in a potentially explosive atmosphere need to comply, in addition to the Machinery Directive, as appropriate with the requirements of both ATEX Directives 94/9/EC (since 20 April 2016, 2014/34/EU) and 1999/92/EC respectively – relating to design and manufacture of such equipment and the health and safety of workers potentially at risk of explosive atmospheres.

- Steam turbines cannot give rise to a potentially explosive atmosphere by themselves but may be installed in a potentially explosive atmosphere originating from external sources (e.g. when gaseous hydrogen used as a turbo-generator coolant, being released and mixed with the air, contributes to classification of zone around the turbine).

- In normal circumstances, a steam turbine could have hot surfaces above the auto ignition temperature of the external potentially explosive atmosphere. The surface temperatures depend on the temperature of incoming steam which is supplied by an external source such as a boiler.

- A steam turbine which has surface temperatures that can lead to the ignition of a potentially explosive atmosphere cannot comply with the relevant provisions of Directive 2014/34/EU. In such circumstances additional measures are required.

2. Given the above, the obligations of the manufacturer and user of steam turbines need to be considered. It should be noted that in all instances of the following guidance the general concepts described for "Place of intended use" (see section § 35) and for "Interface to different potentially explosive atmospheres" (see section § 36) will apply (e.g. ATEX compliant equipment must be used, where applicable, inside machinery).

- The manufacturer can ATEX certify the steam turbine for use in external potentially explosive atmospheres with auto ignition temperatures above the specified maximum steam inlet temperature.

- Although manufacturers must, to the state of the art, eliminate or control sources of ignition, it may not be technically possible to reduce the temperature of all hot surfaces to comply with the essential health and safety requirements of the ATEX Directive 2014/34/EU.

- The main measure for safety is to prevent the explosive atmosphere from being in contact with the hot surfaces of the steam turbine, e.g. by an over-pressurised enclosure.

- A supplier (this may be the turbine manufacturer, packager, installer, final supplier, etc. and in some cases the end user) delivering steam turbine machinery and associated safety devices is responsible for risk assessment and implementation of the chosen basis of safety under Directive 2014/34/EU. Irrespective of the chosen basis of safety if there is the potential for an explosive atmosphere to arise near the turbine, and proper consideration should be given to minimising the risk of ignition. The supplier as described above is also responsible for the communication of instructions for safe use and any residual risk to the end user sufficient for the completion of risk assessments under the relevant workplace directives.

- Interested parties should consider the provisions of the ATEX Directive 2014/34/EU and guidance documents with further information on the relevant responsibilities.

3. In full application of the above guidance, a steam turbine as a complete machine the ignition sources of which have no interface to a potentially explosive atmosphere outside the enclosure does, however, not fall under scope of the ATEX Directive 2014/34/EU and as such cannot be affixed with the special marking for explosion protection and other marking detailed at Annex II, EHSR 1.0.5. of the Directive.

4. It is evident that a steam turbine, delivered as a complete machine by one supplier, is considered to be an assembly in the sense of Directive 2014/34/EU and shall be marked accordingly, if it is intended to be used in a potentially explosive atmosphere.

§ 246  Petrol pumps

Whilst categorisation of equipment was always the sole responsibility of the manufacturer, the view of the majority of the ATEX Committee considered that, under normal circumstances, petrol pumps may be suitably categorised as category 2.

Given this, and the fact that the assembly is sufficiently complicated and includes an electrical motor – with an additional ignition hazard as a result of assembling pump and motor –, the majority of the members concluded that notified body intervention with respect to the completed assembly was required, in line with the complete conformity assessment procedures outlined in the ATEX Directive 2014/34/EU (Annex III: EU-type examination).

See also section § 45 on assemblies, point 2c).

§ 247  Cables

The question arises, should cables be marked according to the ATEX Directive?

Cables are not covered by the product-related ATEX Directive (neither as equipment neither as components) because in most cases they fall into the field of installations, and as such, cables have never been regarded as an ignition source of considerable risk in hazardous areas if protected properly in a mechanical and electrical manner.

Furthermore and with a view to the extreme variety of possible situations of application in equipment devices in the scope of Directive 2014/34/EU, a reliable and serious list of ATEX-conforming cables seems not to be practicable. End-users and installers may choose cables according to the state of the art and according to the requirements of the Low Voltage Directive 2014/35/EU. Cables conforming to the latter Directive are considered to be adequate for use in products falling under the scope of Directive 2014/34/EU.

Consequently, cables should bear no marking according to the ATEX Directive 2014/34/EU.

§ 248  Rotating mechanical seals

The question arises, when a Mechanical Seal.is a Machinery element and when an ATEX component?

Definition: A mechanical seal is a device which prevents leakage of fluids along rotating shafts. Primary seal function is at right angles to the axis of rotation between one stationary ring and one rotating ring.

Machinery element: These are parts of Machinery not defined within Directive 2014/34/EU.

Most mechanical seals are machinery elements. Typically these seals are:

  • Catalogue mechanical seals and their parts, selected by the equipment manufacturer alone or with assistance from the mechanical seal manufacturer.
  • Mechanical seals stocked by the equipment manufacturer or end user for general applications
  • Mechanical seals used for applications where the service conditions are not closely specified
  • Non cartridge-seals and parts.
  • Standard cartridge-seals.

Mechanical seals will also be machinery elements if a risk assessment by the mechanical seal or equipment manufacturer shows that the seal is not expected to be an ignition source even in the event of fault conditions.

ATEX component:

The two defining elements for components are that they,

- are essential to the safe functioning of equipment and protective systems with respect to explosion protection (otherwise they would not need to be subject to the Directive);

- with no autonomous function (otherwise they would have to be regarded either as equipment, protective system or as device according to Article 1).

Engineered mechanical seals maybe classified and sold as ATEX components. Typical examples are:

  • Mechanical seals for specific applications where close co-operation between mechanical seal manufacturer and equipment manufacturer is required and will often result in a specifically designed mechanical seal.
  • Mechanical seals for some category 1 equipment.

In this case the mechanical seal manufacturer shall supply sufficient information about the performance of the seal so that the equipment manufacturer does not need to repeat unnecessary efforts such as tests or calculations concerning the mechanical seal in order to ensure that the equipment complies with ATEX requirements. The equipment manufacturer shall supply sufficient information about the intended application and equipment.

Responsibilities:

A) Mechanical seal manufacturer:

Case 1: Mechanical seals supplied as Machinery elements

It is normal practice that the manufacturer of mechanical seals supplied as Machinery elements provides complete documentation for safe use of his product, i.e.: instruction manual for incorporation into equipment, which shall include safety aspects and limits of operation.

Case 2: Mechanical seals supplied as ATEX components

Mechanical seals shall comply with Article 13(3) of the ATEX Directive 2014/34/EU.

An ATEX-component mechanical seal shall be supplied at least with the following information:

- all information/documentation given for case 1

- results of relevant calculations and/or tests that have been carried out

- a temperature rating as far as possible

- an indication of the category

- a list of ATEX essential safety requirements that the mechanical seal complies with

- what fault conditions have been considered for category 1 or 2 mechanical seal

- a close specification for intended use, for example gas group

- a certificate of conformity

- marking for components in accordance with the Directive.

B) Equipment Manufacturer:

In all cases the equipment manufacturer is responsible for the entire package within his scope of supply and therefore it will be required to comply with Article 13(1) of the ATEX Directive 2014/34/EU.

§ 249  Bucket elevators

The question arises, how are bucket elevators to be treated within the framework of Directive 2014/34/EU especially in respect that in the surrounding area of bucket elevators potentially explosive areas are not necessarily present?

The intention of Directive 2014/34/EU is to avoid the ignition of potentially explosive atmospheres by equipment, protective systems and components. According to the potential hazards and the prevention measures the products are divided into categories.

Directive 2014/34/EU defines a potentially explosive atmosphere as an atmosphere, which could become explosive due to local and operational conditions. This means that the potentially explosive atmosphere is either present from the beginning or develops during the working process (e.g. in relation with the conversion of energy or the processing of materials).

In bucket elevators the potentially explosive area is limited in general by housings and/or sheathings, whereby a multiplicity of potential ignition sources can become effective due to construction, for example by rubbing and flapping sparks or by inadmissible heating.

A manufacturer of bucket elevators has to analyse all potential ignition sources (e.g. belts, buckets, angle wheels, drive units, regulating devices) and preventive measures according to design, transported material, transport speed etc. under the aspect of the intended use of the equipment.

The necessary level of protection of equipment and components inside the housing (e.g. category) depends on the frequency and the occurrence of the explosive atmosphere inside this housing.

According to the necessary level of safety, depending on their incorporation in the housing and the disturbances or equipment faults which have normally to be taken into account, some components (presenting a higher risk) might be assigned to categories different to the entire category of the bucket elevator.

If some ignition sources cannot be avoided by the design of equipment or components, the manufacturer of the bucket elevator has to avoid the transmission of explosion to all the process.

§ 250  Fork lift trucks

Fork lift trucks intended to be placed on the EU market for use in a potentially explosive atmosphere are considered assemblies (see section § 45). They must also, where relevant, comply with other applicable directives (e.g. Machinery 2006/42/EC, Electromagnetic Compatibility 2014/30/EU).

A fork lift truck, which complies with all applicable directives, must be placed on the market by a single responsible person. More than one CE marking, EU declaration of conformity, etc. makes it unclear who is responsible for the compliance of the final product and is not acceptable.

The responsible person must have the means to show that there is full compliance with all applicable Directives, also those dealt with by possible subcontractors.

Selection of the conformity assessment procedures

The conformity assessment procedure according to Directive 2014/34/EU depends on the category of the product. In the all well-known cases explosion-proof fork-lift-trucks are to be assigned to the categories 2 or 3.

Fork lift trucks can be regarded for the selection of the conformity assessment procedure as combined equipment which if necessary contains an internal combustion engine, as well as different electrical and non-electric devices.

Fork lift trucks category 2:

- Internal combustion engines and the electrical equipment must be submitted to the conformity assessment procedure in accordance with Article 13(1)(b)(i) of Directive 2014/34/EU; for both, the procedure of the conformity assessment procedure according to the Article 13(1)(b)(i) is to be accomplished by a notified body in any case.

- The manufacturer has to ascertain that there are no additional ignition risks due to the combination of electrical equipment. This means for example a change of the temperature class. Usually the combination of components (EU-type examination certificate of components) does not fulfil these requirements.

- The combined equipment (fork-lift truck) is neither electrical equipment nor another internal combustion engine, therefore Article 13(1)(b)(ii) of Directive 2014/34/EU applies to the conformity assessment procedure for the category 2: The manufacturer must use the internal production control in accordance with Annex VIII (including design and production) and deposit the technical documentation with a notified body in accordance with Article 13(1)(b)(ii); the notified body has to confirm the receipt of these documents immediately.

Fork lift trucks category 3:

For category 3 the manufacturer must use the procedure of the internal production control in accordance with Annex VIII to Directive 2014/34/EU.

All fork lift trucks categories:

In all categories, the manufacturer can choose to use the procedure of the unit verification according to Annex IX to Directive 2014/34/EU.

Other Directives applying

The manufacturer has to fulfil the requirements of all Directives appropriate to his product. In particular, the manufacturer has to guarantee that the fork lift truck complies with the essential health and safety requirements of the Machinery Directive 2006/42/EC in the case of conversion to an explosion proof fork lift truck.

EU declaration of conformity

Preferably the manufacturer should draw up a EU declaration of conformity which summarizes the EU declarations of conformity for all Directives applying. Alternatively the EU declaration of conformity according to the Machinery Directive 2006/42/EC and/or the Electromagnetic Compatibility Directive 2014/30/EU can be issued separately.

§ 251  Transportable, pressurised cabins ("modules")

This section deals with the application of the ATEX Directive 2014/34/EU to transportable pressurised cabins (or "modules"), as such goods are considered to be in-scope of the Directive.

Cabin description

Such cabins are often intended for use in a zone 1 or zone 2 hazardous area and are used at both onshore and offshore sites (e.g. fixed drilling platforms). The cabins are pressurised with breathable air both to exclude ingress of flammable gas and to provide a safe atmosphere for operators to work inside the cabins.

The cabins are supplied to meet a variety of purposes, e.g. laboratory, control cabin, office or workshop. They are placed on the market in their finished state, ready for use, but "empty" – suitable for the customer to install and use their own equipment inside the cabin.

The design includes the incorporation of a number of ATEX-certified items, such as fire and gas detection systems, automatic shutdown systems and ventilation fans.

The design ensures positive pressure inside the module to prevent the ingress of flammable gas. As long as there is no internal source of release, this allows the enclosed area to be regarded as a non-hazardous area (reference, for example, UK Institute of Petroleum Code IP 15, section 6, 2002).

The cabin interior is often fitted with unprotected electrical fittings such as luminaires, switches and socket outlets. Should the cabin suffer a loss of pressure, these items have the potential to be exposed to an ingress of flammable gas which may form a potentially explosive atmosphere.

Therefore, the cabins are designed with many safety features to prevent this situation, such as smoke and gas detectors and alarms and the automatic shutdown of non-certified electrical equipment being used inside the cabin.

Application of 2014/34/EU

Where a manufacturer assembles and supplies a product which includes a number of ATEX-certified items (as is the case here), they are responsible for assuring that the process of design/ manufacture has not introduced any additional ignition sources or other relevant hazards and for having the assembly ATEX certified.

The ventilation system for these cabins should be viewed as a protection device, from the definitions in the Directive. A pressurisation fan and a long length of ducting are incorporated, so that the fan can be deployed in a remote, safe area. Therefore, the safe operation of the pressurisation system also needs to be assured. The module itself forms the pressurised enclosure and must therefore be subject to conformity assessment, which would need to demonstrate the effective application of the pressurisation concept (including consideration of the safety integrity of the pressurisation control system) so as to meet the essential health and safety requirements of Directive 2014/34/EU.

The European harmonised standard EN 50381:2004 Transportable ventilated rooms with or without an internal source of release covers the essential health and safety requirements of Directive 2014/34/EU and applies to the cabins covered in this paper. "Ventilation" in this standard is used as a means of explosion protection ("ventilation" is also being used in these particular modules to ensure adequate air quality for personnel working inside. However, this aspect is out with the scope of the standard).

An alternative route to compliance is for the manufacturer to demonstrate that the essential health and safety requirements of Directive 2014/34/EU have been met. This would include demonstrating the effective application of the pressurisation concept, including consideration of the safety integrity of the pressurisation control system.

It is stated in EN 50381:2004 that it is not the intention of this standard to cover stationary analyser houses according to EN 61285:2004 Industrial-process control - Safety of analyser houses.

User's responsibilities

The installation of the cabin in accordance with the manufacturer's instructions is common to many ATEX products and shouldn't require further certification by/for the end user. The only circumstances when the end user would need to undertake ATEX conformity assessment under Directive 2014/34/EU would be if they made any changes which affected the explosion safety features of the product or if they needed to install it in a manner which was not in accordance with the manufacturer's instructions. These instructions should also state any limitations on the use of (non-protected) equipment inside the cabin.

§ 252  Automatically lubricating systems

Facts of the case:

A lubricant dispenser has a housing, a piston subdividing the housing into a pair of compartments one of which is generally closed and the other of which is adapted to be connected to a machine to be lubricated.

(see the picture below)

ATEX 2014/34/3U-application guide

In the closed compartment the plus- minus- poles are in contact with a gel and the production of gas is activated by an electric short circuit. The amount of gas pro time unit will be regulated through an electrical resistance. The greater the resistance, the slower the production of gas. The amount of gas is proportional to the current which flows through the battery. If the supply is interrupted, the gas production will be stopped for a short period of time.

The lubrication systems have one or two electric battery cells. The electric values of the battery cells are above the values specified in EN 60079-11, Chapter 3.11 and 5.7.

The automatic lubrication system is electrical equipment in the sense of the ATEX Directive 2014/34/EU; the battery cells are an integral part of the system.

Annotation: Another possible ignition sources – mechanical or electrostatic – are not to expect.

Discussion:

  • Section § 44: on electrical equipment "as equipment containing electrical elements, used for the generation, storage, measurement, distribution and conversion of electrical energy, for controlling the function of other equipment by electrical means or for processing materials by the direct application of electrical energy. It should be noted, that a final product assembled using both electrical and mechanical elements may not require assessment as electrical equipment provided the combination does not lead to additional ignition hazards for this assembly".
  • Section § 39: "for 'simple' electrical products, European harmonised standards provide a good basis to assess the effectiveness of electrical ignition source and, consequently, to determine whether or not these can be considered effective or not".
  • Section § 43: "Mechanical equipment may be fitted with a thermocouple or similar measuring device that generates only very low voltages and currents. If these measuring devices can be considered as ‘simple apparatus’ (as described in section § 39) and there are no other electrical parts, the equipment should follow the conformity assessment procedures for non-electrical equipment".
  • Draft standard prEN 60079-11 (IEC 31/782/CD):

"5.6 Simple apparatus

The following apparatus shall be considered to be simple apparatus:

a) passive components, for example switches, junction boxes, resistors and simple semiconductor devices;

b) sources of stored energy with well-defined parameters, for example capacitors or inductors, whose values shall be considered when determining the overall safety of the system;

c) sources of generated energy, for example thermocouples and photocells, which do not generate more than 1,5 V, 100 mA and 25 mW. Any inductance or capacitance present in these sources of energy shall be considered as in b).

Simple apparatus shall conform to all relevant requirements of this standard but need not be certified and need not comply with clause 12. In particular, the following aspects shall always be considered".

Conclusion:

The batteries are an integral part of the lubrication system, therefore it is to be regarded as an electrical equipment. An EU-type examination certificate for the lubrication system category 2 is necessary.

Remarks:

- There are lubrication systems without a cell; gas is produced by electrochemical reaction. These lubrication systems are neither electrical nor non-electrical equipment.

- The ExNB Group approved the statement to the automatically lubrication systems.

§ 253  Electrical trace heating systems

Notes:

- This section is only applicable for placing on the market of electrical trace heating systems by a responsible manufacturer as device (electrical equipment according to Directive 2014/34/EU).

- It is not intended to deal with electrical trace heating installations which are designed, installed and inspected according to relevant legal requirements in the Member States.

Certification and installation of different types of construction

(1) Electrical heating systems for use in potentially explosive atmospheres are assemblies, which have to be treated as electrical equipment according to Directive 2014/34/EU. Some safety-relevant characteristics, in particular the temperature class, are determined partly by the design and the installation.

Thus for these products some special requirements for installation are relevant; therefore they are bordering alongside the scope of Directives 2014/34/EU and 1999/92/EC. Due to this circumstance it is essential to determine, who is the responsible person that CE mark the electrical trace heating system and make sure that it complies with all the requirements of Directive 2014/34/EU – the manufacturer, the supplier (designer) or the installer. These questions cannot be answered clearly and comprehensively for all products; the different types of construction and techniques must be differentiated.

(2) The measures to be taken for explosion protection of electrical trace heating systems will depend on the category (respective zone classification), the explosion group, and the temperature class.

Directive 2014/34/EU does not require category 3 systems to be certified by a notified body. The manufacturer has to apply the module as described in Annex VIII, Internal production control or Annex IX, Unit verification of Directive 2014/34/EU for conformity assessment. The manufacturer shall establish an EU declaration of conformity and the technical documentation that enable the conformity of the equipment with the relevant requirements of the Directive to be assessed. Hence, the product should not have the number of a notified body affixed (other than Unit verification).

Installation of trace heating systems is not permitted by industry standards for the application in zone 0 (category 1), so that in the following only remarks for the application in zone 1 (category 2) are being regarded.

(3) It should be noted, that holding an EU-type examination certificate only for particular parts of this system is not sufficient. Because the temperatures can be variable – relying on the type of the heating cables and conditions of installation – each system has to be treated individually, it is unique. According to the design and instructions for use, a certain procedure has to be followed.

Therefore, the manufacturer of the assembly has to use the applicable conformity assessment procedure of the Directive 2014/34/EU for the electrical equipment. For category 2 the manufacturer has to apply the following modules of Directive 2014/34/EU for conformity assessment:

- Annex III and VI, or

- Annex III and VII, or

- Annex IX.

(4) For the EU-type examination we have to differentiate:

       a) "Stabilized Design”

A trace heating system shall be designed so that under all conditions that may reasonably be foreseen the surface temperature of the trace heaters is limited to the temperature classification or ignition temperature, less 5 K for temperatures less than or equal to 200 °C or less 10 K for temperatures greater than 200 °C. Stabilized design shall employ either the product classification approach or the systems approach.

Therefore, the notified body is able to issue an EU-type examination certificate including temperature class. The manufacturer will deliver the heating system parts with the EU declaration of conformity and the instruction manual including design documentation and a marking plate.

The manufacturer will affix the CE mark before the bringing the products into circulation.

An electrician with adequate knowledge of explosion protection can perform the installation and putting into service, unless otherwise specified by the manufacturer in the instructions. The manufacturer will specify the necessary skills of the staff in the instructions for use. These requirements in the instructions for use are to be examined within the course of the EU conformity assessment procedure.

       b) "Controlled Design”

Controlled design applications require the use of a temperature control device to limit the maximum surface temperature. The limit controller shall operate independently from the temperature controller. A protective device such as a temperature limiter shall be provided that will de-energize the system to prevent exceeding the maximum permissible surface temperature. In case of an error by, or damage to the sensor, the heating system shall be de-energized before replacing the defective equipment.

The T-Class depends on the layout (e.g. fixed setting point of monitoring device) and the correct installation (e.g. defining the “hot-spot” and the correct positioning of the temperature sensor). The manufacturer of the system has given precise instructions for the design and installation and for the necessary qualifications of the installation staff.

The “temperature monitoring” method can provide a false presumption of safety if not applied correctly. Simply applying a temperature safety device, which is set to the limiting temperature, is not acceptable. No matter how the sensor of the safety device is mounted, there will always be an offset between the actual maximum surface temperature of the hottest point in the system and the set point of the safety device. That offset is usually considerable and depending on:

- the position of the sensor with respect to the tracer geometry or position;

- the location of the sensor in the system;

- the hysteresis or control band of the protective device;

- the heat transfer between tracer, sensor, work piece and ambient.

The T-Class mentioned in the EU-type examination certificate is based on verified design calculations of the manufacturer, predicting the offset between limiter set point and the actual maximum surface temperature of the trace heater in the system. In this case, the maximum surface temperature depends on the correct installation, correct location, and position of the sensor and the incorporation of the applicable temperature offset in the set point of the safety device.

In the instruction manual the manufacturer of the system may recommend a check of the skills/qualification of the personal. These requirements, laid down in the instructions for use, are to be examined within the frame of the EU conformity assessment procedure. The result should be a system certificate.

Bringing into circulation of the system by the manufacturer is to be done with the specified parts, accompanied by the EU declaration of conformity, and the instruction manuals including design documentation and a marking plate.

The installation and putting into service can be done by the following alternative options:

1) This option is only permitted in case the manufacturer is a holder of a EU-type examination certificate according to Annex III (EU-type examination) for the complete trace heating system in combination with a quality assurance notification according Annexes VI or VII (respectively Conformity to type or Product quality assurance). The manufacturer may select a specialised company for explosion protected heating systems as a subcontractor. The subcontractor has to have access to the descriptive documents referred to in the EU-type examination certificate and meet the skills/qualifications as defined in those documents. The specialised company may be qualified by the holder of the EU-type examination certificate or a similarly authorized entity/body.

2) The manufacturer may select the conformity assessment procedure of Annex IX (Unit verification).

The marking plate and the CE mark will be affixed by the manufacturer or – under the manufacturer's responsibility – by his subcontractor.

Note: The aforesaid does not replace inspections of installation which are required by Member State legislation in the field of Directive 1999/92/EC.

(5) Additional Remarks for electrical trace heating systems of category 3 for use in zone 2

The installation of a heating cable and combination with a temperature control component may result in equipment according Directive 2014/34/EU Article 1(1). An own potential source of ignition may be generated by installation (e.g. hot spots) or by false design and set-up of the control unit.

In contrast to technical faults, which normally have to be taken into account, these thermal potential sources of ignition exist for a long time or permanently and increase the probability of explosion even in cases of explosive atmospheres persisting for a short period only – zone 2.

The manufacturer of heating systems of category 3 for use in zone 2 issues an EU declaration of conformity without involving a notified body. In Annex VIII are some technical requirements are specified. Especially the items 2 and 3 are to be described in detail for heating units with relevant documentation of the competence of the persons, who design and install the heating system.

If the same manufacturer also puts heating systems of category 2 on the market for use in zone 1, the evidence of the competence as mentioned above can be given during the certification process for the QM-system.

 

Annex 1

Example of a trace heating system:

trace-heating-system-2014-34-EU

For design, installation and maintenance the application guide EN 60079-30-2 Explosive atmospheres - Part 30-2: Electrical resistance trace heating - Application guide for design, installation and maintenance may be used. This guide is written in conjunction with the product standard EN 60079-30-1 Explosive atmospheres - Part 30-1: Electrical resistance trace heating - General and testing requirements, according to which trace heating systems for use in potentially explosive atmospheres are usually assessed and certified.

 

Annex 2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Click on the figure to enlarge


[1]

EN 60079-2:2007 Explosive atmospheres - Part 2: Equipment protection by pressurized enclosure ‘p’ (IEC 60079-2:2007)

[2]

Annex II, EHSR 1.3.1 "Potential ignition sources such as …, high surface temperatures, … must not occur".

[3]

Dilution ventilation reduces the size of any flammable cloud to below that which would result in a hazardous explosion if ignited. In order that the dilution ventilation ensures a negligible risk of an explosive atmosphere at all times, the ventilation system should have additional safety features such as e.g.: a 100% standby fan; an uninterruptible power supply to the ventilation fans; interlocks so that the gas turbine cannot start without sufficient ventilation; proven automatic isolation of fuel supply if ventilation fails.

[4]

Annex II, EHSR 1.3.1 "Potential ignition sources such as …, high surface temperatures, … must not occur".

[5]

This section does not consider mechanical seal control systems.

[6]

The currently harmonised standard is EN 60079-11:2012 Explosive atmospheres - Part 11: Equipment protection by intrinsic safety "i"

[7]

Trace heating system: the system is mainly externally applied to equipment and used to maintain (or raise) the temperature of contents in piping, tanks, and vessels. A complete trace heating system consists of:

- electrical resistance trace heater unit (heating cable or pads)

- possibly monitored by temperature controllers and/or limiters

- installation accessories, like terminal enclosures, connectors and splice kits

- thermal insulation and weather barrier (cladding).

The system also includes the appropriate marking and system documentation (operating manual, design documentation, test certificates, declarations of conformity, etc.).

System components: all of the components necessary for the safe use as intended of an electrical trace heating system. These components must have either separate EU-type examination certificates or they must be included in a heating system certificate.

[8]

See also Annex 2 to this section “Type A” and “Type B”
.

 
 
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