Global conformity assessment using the IECEx system

In the nineties, before the turn of the millennium, preparations for a fully harmonised internal market for explosion-protected products were under way in Europe. At the time, this inspired a number of European and non-European experts to question whether it would be possible to convert the heterogeneous, nationally specified conformity assessment landscape to a homogeneous, harmonised system at a global level. The outcome of these deliberations was the creation of a working group within IEC Technical Committee (TC) 31, tasked with developing a global conformity assessment system for explosion-protected products. The first official meeting of this working group was held in London in 1996. This marked the birth of the IECEx system. While ATEX Directive 94/9/EC was being introduced by all European member states as a high priority, coordinated among the states, and when it was successfully enforced in 2003, the first few years of the IECEx system were, for the most part, uneventful. Initially, enough member states needed to be sought out that were ready to collaborate on the development of suitable structures and fundamental rules. The significant, underlying difference between the ATEX directive and the IECEx organisation is that the former is a binding legal framework (legislation) within the EU, while the latter is a concept based on voluntary engagement and mutual recognition. The IECEx system can only become legally binding if it is declared to be applicable legislation in a sovereign field of law. Up to now, however, this is only the case in a few nations.
The successful introduction of ATEX 94/9/EC in Europe provided the IECEx system with a renewed boost. In the year when the European directive came into force, the number of published IECEx certificates jumped from 11 to 98; since then, the annual growth of the IECEx certified equipment scheme has continued at the same rate. In the year 2020 alone, 4650 certificates were issued for explosion-protected products.
Unlike in Europe, where conformity assessment is limited to the commissioning and/or market placement of the products, after a few years, IECEx activities began expanding to include additional important stages in the life cycle of the product, as the result of an initiative started by end customers in the process industry. In 2007, this resulted in the creation of the IECEx service facility scheme, which deals with the conformity assessment of service providers such as repair workshops. Eventually, in 2010, the first people were assessed with respect to their competence when performing work for and in hazardous areas within the framework of the personnel competence certification scheme. At the end of 2020, there were already more than 4000 certified specialists in explosion protection. Over the course of this diversification, the superordinate IECEx system, which consists of the aforementioned elements (schemes) was brought to life.

The IECEx system is a sub-organisation within the International Electrical Commission (IEC).
The IEC is the global organisation for standardising the functionality and safety of electrical and electronic products. As well as the creation and and maintenance of standards in more than 200 Technical Committees (TCs) and sub-committees (SCs), this organisation uses four systems to govern the conformity assessment of products, services and professional expertise. The IECEx system is one of these and, like the others, is guided by the Conformity Assessment Board (CAB). The members of this board include a representative for each of 15 IEC member states, including Germany. The Chairman and Executive Secretary of the IECEx system report to the board twice a year to update it on the most important ongoing tasks. 
Fundamental decisions within IECEx are made once a year as part of the IECEx Management Committee (ExMC) meeting. Each of the 36 current member states can send a three-person delegation to this meeting to vote for or against specific suggestions on behalf of their country. The operative business that goes on throughout the year is primarily managed by the IECEx Secretariat in Sydney. 
The primary tasks this involves include:

• Coordinating assessments by certification bodies (ExCBs) and the test laboratories (ExTLs) (see below)
• Maintaining the structure and content of the IECEx website as the central information platform
• Maintaining the online certificate database, which provides round-the-clock global access to all IECEx certificates
• Ensuring correct implementation of all quality and compliance rules
• Clarifying disputes between manufacturers and certification bodies, or other parties

The IECEx system must be considered as a network of independent international test bodies (ExCBs and ExTLs).
Before initially being recognised in the IECEx system, these are systematically evaluated by IECEx assessors. The assessors, who are all selected experts in the field of testing and certifying explosion-protected products, review submitted documents and use these, along with comprehensive audits of the candidate, as the basis to establish the degree to which they meet the requirements set out by the IECEx system. They then create an assessment report, which is distributed to the IECEx member states via the IECEx Secretariat. If the majority of the member states approve the report, the certification or testing body in question is accepted into the IECEx network and can then perform type tests on explosion-protected products and/or issue IECEx certificates within the agreed scope. Within the framework of the IECEx certified equipment scheme, there were 60 recognised ExCBs and 68 ExTLs at the end of 2020. These operate independently together with their customers – the manufacturers – but are regularly monitored by the IECEx Secretariat. The scheduled monitoring includes repeated audits by IECEx assessors after five years, and a review of the relevant documentation after two and five years. In addition, the IECEx Secretariat also checks the content and accuracy of randomly selected IECEx certificates and test reports (around 10% of those issued during the year).
To guarantee the required quality and comparativeness of the testing and certification results, regular coordination and training events are held as part of the Ex TAG (Technical Advisory Group), in which all ExCBs and ExTLs are represented. Furthermore, within the framework of the proficiency test programme, the results of specific, standardised type tests are compared across all ExTLs and the relevant skills for performing tests are harmonised in workshops. Participation in this programme is obligatory for all ExTLs. The Ex-Magazine will contain a special report on this topic later in the year.
The www.iecex.com website, which includes an integrated online database of all valid certificates, is essential to the success of the IECEx system. Users can visit this website to discover a range of additional information, as well as all documents within the IECEx system, which are available to download for free. The hierarchy of these documents is as follows:

• IECEx Rules of Procedure: These general basic rules relate to how the IECEx system works, the rights and obligations of involved user groups, organisational integration into the IEC, etc.
• Operational Documents (ODs): These documents govern all activities and structures within the IECEx system precisely and in detail. 
• IECEx Guidelines: These are simplified depictions of the most important processes in the IECEx system, intended to make it easier for new users to get to grips with the testing and certification processes.

Some of these documents are presented below, using selected conformity assessment processes as examples. 
In principle, the ATEX and IECEx conformity assessment procedures differ in that the former stipulates compliance with the framework set out in Annex II of 2014/34/EU, while IECEx requires compliance with the requirements set out in the applicable standards. These standards are, in essence, the documents in the 60079 and 80079 series issued by IEC TC 31.
The practice of the manufacturer creating a declaration of conformity, as well as the manufacturer's sole responsibility for products in Category 2 (non-electrical explosion protection – module A: Internal production control), which are typical of ATEX, are not applicable under IECEx. 

Each IECEx product certificate must be issued on the basis of a valid standard by an IECEx certification body (ExCB). An additional feature of explosion protection according to the IEC, compared to ATEX, is the Equipment Protection Level (EPL). The following classifications are analogous to ATEX:

Below, this article discusses conformity assessment within the IECEx certified equipment scheme in more detail:
A manufacturer wanting to have their product certified in accordance with IECEx can find all the required documents free of charge on the IECEx website . The IECEx 02A guide [1] is an ideal initial introduction.
A suitable ExCB can be selected from a list on the IECEx website under "Information". When doing so, it must be ensured that the listed scope of the ExCB in question corresponds to the selected ignition protection concept (method of protection). Before an application for testing and certification can be submitted, an internal check should be performed in order to make sure that the following conditions are met:

• The product to be tested meets the requirements of the applicable standards.
• The manufacturing process has been designed according to the requirements of ISO 9001 [2] and ISO/IEC 80079-34 [3].
• The product documentation meets the requirements of IECEx OD 017 [4].

If this is the case, the selected ExCB can be contacted. They will then provide the manufacturer with a proposed time frame and costs, as well as the required application documents. As a rule, ExCBs also publish their specific processes online .
At the start of the collaboration, the precise procedure for testing and approval is discussed. The type and number of the test samples for the type test, as well as the scope of the product documentation to be provided, are agreed upon. The ExCB then specifies an ExTL with which they are contractually bound, who will perform the type tests defined in the applicable standards. To do so, the manufacturer must provide the agreed number of test samples in the condition specified by the ExTL. Next, the ExTL will perform the type tests and produce a corresponding test report (ExTR), which is provided to the manufacturer and the contracting ExCB. The manufacturer is the owner of this ExTR. Under specific circumstances, which are defined in Operational Document OD 024 [5], the manufacturer may perform some of the type tests in its own laboratories. This collaboration is contractually agreed between the ExTL and the manufacturer and the tests are performed under appropriate supervision by employees from the ExTL.
As well as the type tests on selected product samples, regular audits at the manufacturer's production facilities are used to assess their quality capabilities. The basis for this assessment is ISO 9001 [2], supplemented by ISO/IEC 80079-34 [3].
This process of auditing the quality management systems at all the manufacturer's production facilities is performed by a single ExCB and repeated at regular intervals. These intervals are:

• 18 months for a manufacturer whose quality management system is audited according to ISO 9001 by an accredited organisation 
• 12 months for all other manufacturers

After the audit, the test body issues a Quality Assessment Report (QAR). 

Both documents – the ExTR and QAR – are used by the responsible ExCB as a basis for issuing a product certificate, the Certificate of Conformity (CoC).
Both underlying documents must present a positive result. In the QAR, it is also important to ensure that the audited QM system encompasses all types of protection listed in the CoC.
It should also be ensured that the IECEx certificate, which is solely valid for the corresponding entry is entered into the IECEx online database by the issuing test body (ExCB). To do so, each test body has specific access rights for the database content. Of course, these certificates can be printed; however, no official, signed and stamped versions are available, as was common in the past. 
Unlike the Test Report, the product certificate remains the property of the issuing test body and can, in extreme cases, be suspended or revoked by the test body if the manufacturer breaches the IECEx rules. To an extent, this acts as a market surveillance function within the global certification network. 
In the past, this option has only been necessary in a few, isolated cases.
One frequently asked question relates to the period of validity of IECEx certificates, particularly with reference to new versions of the IEC standards on which the certificate is based. On this topic, basic rule IECEx 02 [6] clearly states that an IECEx certificate is valid for an unlimited length of time, which cannot be restricted by new versions of standards. In the extremely unlikely event that, during the continued development of IEC standards, severe safety-related concerns arise relating to the old version of the standard in question, it is stipulated that the IECEx management committee (see above) will make a decision regarding the continued validity of the affected certificates.

As described above, a valid standard must form the basis for each IECEx product certificate. This means that it is not possible to perform certification based on framework specifications, as is possible with Annex II of ATEX 2014/34/EU. In any case, IECEx must also meet industry representatives' request that new, innovative solutions are quickly incorporated into product certificates, even when they have not yet been incorporated into the basic standards. For this purpose, IEC TC 31 developed the IEC 60079-33 standard [8], which was published in 2016.
This document sets out a framework, within which the essential safety requirements must be met by innovative solutions, in a similar manner to ATEX – but fixed in a fully-formed IEC standard. On the part of the IECEx system, the certification process is described in Operational Document OD 233 [9].
In principle, manufacturers are asked to initially check whether the product they have designed can be implemented using one or more existing types of protection. The use of the "s" special type of protection in accordance with IEC 60079-33 should thereby be limited to truly innovative products, for which there are currently no specifications in the applicable standards (or draft standards). Certification in accordance with IEC 60079-33 can be performed only if this is not the case. The path to ensuring that an explosion protection concept is sufficient may include:

• Completely new solutions, which have not yet been partially covered by a method of protection
• Solutions that are based on one or more methods of protection, but not fully covered by these
• Solutions for which the desired application area is outside the limits defined in existing standards (e.g. ambient pressure or temperature, oxygen content in the air)

Like all equipment, any equipment protected using the "s" special type of protection must be classified using an Equipment Protection Level (EPL).
As a particular detail, IEC 60079-33 introduces the role of the independent verifier. According to the definition in [8], this refers to a legal person (an individual or an organisation) with sufficient specialist expertise in the protection technology to be assessed. (This expertise is described in detail in [8].) They are responsible for the assessment of the relevant calculations, the construction principle and the results of type tests that have been performed. One important condition is that the verifier must be entirely independent in their decision-making. A verified of this kind may be an employee of an ExCB or ExTL, but also an external person or organisation. The relevant ExCB must compile a list of their own verifiers, which must also include their expertise and tasks. These records are checked regularly by IECEx as part of the usual assessment.

In order to meet the relevant requirements for the EPL in question, IEC 60079-33 requires:

• Assessment by one independent verifier for the lowest EPLs, Gc and Dc
• Assessment by two independent verifiers for the medium EPLs, Gb and Db
• Assessment by three independent verifiers for the highest EPLs, Ga and Da

The significant importance of the independent verifiers is also emphasised by the fact that [8] requires them to be directly informed about IEC TC 31 activities or actively involved in these activities. This is intended to ensure that the verifiers are always up-to-date with the latest developments in explosion protection technology. 
The standard also contains general information for each EPL about the absence of ignition sources; the manufacturers are also required to perform a systematic ignition source analysis, which must be confirmed by the independent verifier or verifiers. The process of ignition source analysis corresponds to the process described in EN 13463-1:2009 [10], to which the ISO/IEC 80079-36 standard refers as a basic standard [11].
The "s" special type of protection is specified on the label of the device. If additional methods of protection are used, these must also be specified. 
[11] also states that it may be necessary for the specific production conditions associated with the special type of protection to be assessed by means of a specific quality management system audit.

Within the framework of the global IECEx system – just like within the scope of ATEX – there is a requirement to certify assemblies that consist of certified and non-certified devices, components and the associated electrical and mechanical connection elements as a whole. In these cases, too, the basic requirement for issuing an IECEx certificate is that the requirements of a valid IEC standard or, if appropriate, an IEC Technical Specification (TS) must be met. For this reason, a document of this kind must first be created before certification work starts. This project was met with a huge response within IEC TC 31, as evidenced by the extensive participation in the assigned Maintenance Team (MT) and the extremely short development time. At the beginning of 2015, more than 50 international experts participated in the first meeting of the Maintenance Team in Windsor, UK; the finished Technical Specification IEC TS 60079-46 was published in August 2018 [12]. The following are not part of the scope of the TS:

• Devices that, as a whole, are protected by one or more types of protection, tested and certified, e.g. complete low-voltage switching systems or distribution boards
• Spaces that are protected using an overpressure or artificially ventilated in accordance with IEC 60079-13 and/or IEC TR 60079-16
• Installations in operators' systems that have been set up according to the rules  in IEC 60079-14

At IECEx, the testing and certification of assemblies is performed according to rules that are similar to those within the scope of ATEX. The decisive criteria are, firstly, the existence or lack of individual IECEx certificates at device level for the individual devices and components within the assembly and, secondly, the risk assessment regarding the construction of the assembly. If no certificates are available for individual devices, these devices must be tested and assessed in accordance with the applicable standards and within the framework of testing and certification of the entire assembly. Since new ignition hazards may arise during construction of the assembly, an ignition source analysis must be performed according to ISO/IEC 80079-36 [11]. The electrical connections between the devices within the assembly must be established according to the specifications of IEC 60079-14 [13].
Unlike the ATEX rules, IEC TS 60079-46 does not differentiate between fully and precisely specified assemblies, on one hand, and assemblies with a modular design that can be laid out in different configurations, on the other. However, the latter is not explicitly excluded and should be agreed upon by the manufacturer and IECEx certification body.

Due to the novelty and complexity of this topic, a special IECEx Operational Document (OD 280) [14] has been created. This is intended to be used as a guide for manufacturers, certification bodies (ExCBs) and test laboratories (ExTLs).
It is expected that manufacturers will prepare and perform an ignition hazard assessment in accordance with IEC 80079-36 [11]. The method itself is described in detail in a separate article in the Ex-Magazine. If necessary, manufacturers should assign expert members of staff to the assessment team. In order to ensure an effective, efficient transfer of information, this is clearly advisable in special circumstances. The test samples submitted for testing and assessment should be accompanied by comprehensive documentation according to the requirements of OD 017 [4].
Each ExCB can, to a significant extent, independently specify how the manufacturer's ignition hazard assessment should be evaluated for plausibility and accuracy. However, some basic prerequisites for this are described in OD 280, such as:

• The ExCB should put together an expert team, which can also include manufacturer's representatives
• In collaboration with the ExTL and the manufacturer, a project plan containing the sequence for testing and assessment, as well as the applicable standards, should be created
• This project plan should also include the required tests performed by the ExTL, as well as the tests at the manufacturer's laboratories that are monitored by the ExTL
• Upon successful completion, a test report (ExTR) is created, containing the detailed results of the ignition source assessment and additional information regarding the tests performed

One important decision to be made by the ExCB/ExTL is the decision regarding the acceptance of test results from third parties. These include, for instance, declarations regarding the material properties of plastics, such as UV resistance and material composition. At this point, it must be noted that often, only the original manufacturer is able to provide the corresponding data. A decision must also be made regarding the use of test results from the manufacturer. To have in-house tests recognised, the manufacturer must obtain consent from the ExCB and meet the requirements in OD 024 [6].
Most machines and equipment are electrically actuated and operated, and perform a mechanical role. As a rule, therefore, both electrical and non-electrical explosion protection elements that need to be certified are typically present. To do so, the manufacturer has the following options according to [12]:

• Certification of only the electrical part
• Certification of the non-electrical part
• Certification of both elements in a single certificate

The first two options may be of interest to manufacturers of devices with a modular design, while the last is suitable for the certification of complete series devices. In these cases, the device description must state which parts of the equipment are recorded in the certificate.