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23. May 2017 | Raw materials

Explosion protection requirements in a new coating

As a rule, manufacturers of solvent-containing paints and varnishes have to prevent explosion hazards and define hazardous areas (zones). Explosive atmospheres may also occur when water-based varnish or powder coatings are used. What should be considered when purchasing or installing explosion-protected equipment?

Explosion protection requirements in a new coating. Source: RioPatuca Images -Fotolia.com

By Dr. Michael Beyer of Physikalisch-Technische Bundesanstalt (PTB), Germany

The main objective in revising the ATEX Directive was to incorporate the principles of the New European Legislative Framework. This framework essentially comprises the regulation or clarification of the legal responsibilities of importers and dealers. Duties involved in production for manufacturers’ own purposes are also detailed in this framework. In the new Directive, "placing on the market” in the old ruling is replaced by "making available on the market and putting into service”, which means that the operator of a device produced in-house assumes the manufacturer’s obligations in such a way that no ambiguity is involved.

By contrast, there are no differences between the two directives as regards the Essential Health and Safety Requirements (EHSR). For this reason, no technical changes are required for explosion-protected equipment. Even existing EC type-examination certificates remain valid in the new legal framework. However, new EU Declarations of Conformity must be issued and attached to each individual product.

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Source: Physikalisch-Technische Bundesanstalt (PTB)

Modified or used products

If the essential characteristics of an explosion-protected product are changed, the responsibility of the original manufacturer becomes void and the company modifying the product becomes the manufacturer of a new product. This implies that all documentation requirements, as well as the technical testing and certification obligations required in certain cases, will be met (EU type examination and production surveillance performed by a Notifed Body). The same applies to production for manufacturers’ own use.

If a (new or used) product is imported into the EU, the legal manufacturer’s obligations have to be fulfilled. Here, legal pitfalls exist that many users of equipment and machines are not aware of. If products covered by a European Directive are bought in non-EU countries, the supplier is not obliged to comply with EU law. In this case, the customer has to ensure that all legal obligations of the manufacturers are met, including documentation requirements and requirements to have testing and certification performed by Notified Bodies. This also applies if the customer receives the products via a fulfillment house (such as Amazon) that acts only as an intermediary.

New international standards for explosion protection of mechanical equipment

International standards ideally allow free international movement of goods to take place without technical adaptations. The benefits of international technology convergence include: significant cost and time savings; improved compatibility; increased transparency with regard to suitability and safety; and, ultimately, greater legal certainty. Considering, for example, the difficulties in standardizing quite simple technical products such as cellular telephone chargers, it may be surprising what progress has already been made in safety-sensitive fields such as explosion protection.

The new standards ISO 80079-36 (Non-electrical equipment for explosive atmospheres – Basic method and requirements) and ISO 80079-37 (Non-electrical equipment for explosive atmospheres – Non-electrical type of protection constructional safety "c”, control of ignition sources "b”, liquid immersion "k”) replace the corresponding parts of the DIN EN 13463 series and now form an integrated and uniform series of standards for explosion protection (IEC 60079 and ISO/IEC 80079) together with the IEC standards for explosion-protected electrical equipment. They are intended to be used as a basis for application in the IECEx global certification system (www.iecex.com, IEC System for Certification to Standards Relating to Equipment for Use in Explosive Atmospheres).

Challenges in the creation of the new standards

The above standards are generally adopted in an unchanged form as European standards. The challenge in the creation of the new standards for mechanical equipment lay in establishing and generating consensus on the known and proven safety principles and technical requirements of the DIN EN 13463 series in an international context. By working in cooperation with European standardization experts, it was possible to include these standards in the list of harmonized standards under the ATEX Directive.

The requirements of the preceding European standard have been almost fully adopted, in particular the central requirement to stipulate necessary protective measures on the basis of an ignition risk assessment. However, many editorial adjustments to these requirements were necessary to ensure their conformance to international standards. These adjustments included the standard’ scope, references to international standards used in place of European standards and marking. The letter "h” now applies generally to all pieces of non-electrical equipment; there will be no separate identification of the types of protection "c”, "b” and "k” on the type plate.

What are the changes?

The new ATEX Directive and the new ISO standards do not require that technical changes be made to explosion-protected equipment. Existing type examination certificates will retain their fundamental validity. However, the EU Declarations of Conformity have to be updated, while mechanical equipment will receive a different marking according to international marking rules in the field of explosion protection.

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