Explosion protection for machine builders

Various requirements are placed on machines in potentially explosive areas. It is important not only to think of explosion protection, but also of other applicable EU/EC directives and their interaction with each other. Of course, the machine (whether “complete” or “incomplete”) must comply with the provisions of the European Directive ATEX 2014/34/EU .

Machine builders often use Ex-certified equipment, components and protective systems and then equip the machine electrically. Among other things, it is important to select the correct electrical and non-electrical Ex devices in accordance with EN IEC 60079-14. The resulting intended use of the machine must always be observed.

Most machine manufacturers also have to think about ignition sources that they bring in themselves. As a rule, the harmonized standards EN 80079-36 and EN 80079-37 are used. If the machine manufacturer uses the concept of “ignition source monitoring”, functional safety requirements (e.g. ISO 13849, EN 61508, etc.) are also applied.

If the machines are to be used in areas (zones) with a high level of risk, the protective measures (categories) for explosion protection must be more complex than in areas in which an explosive atmosphere occurs only rarely and for a short time. It also determines whether a notified body needs to be involved.

Important items
  • Apply ATEX Directive 2014/34/EU correctly
  • Perform ignition hazard assessment
  • Evaluation of Ex-certified equipment
  • Consideration of functional safety
  • Understanding interactions with the Machinery Directive
  • Operating instructions and type plate

Explosion protection topics for mechanical engineers

Answer the following questions:

  • 1. Machinery intended for use in or in connection with potentially explosive atmospheres?

Yes?

  • 2. Machine with its own potential ignition source?

Yes?

If both questions are answered “YES”, your product will most likely fall under the ATEX 2014/34 / EU directive.

One of the first steps in implementing the requirements for your product is to perform an ignition source analysis or ignition hazard assessment. The standard EN 1127-1 and -2 (Mining industry) describes 13 sources of ignition. For non-electrical devices there is a good procedure in the standard ISO 80079-36 (ignition hazard assessment). What device-related effective ignition sources does your product have? And how are these rendered ineffective (= types of protection). It usually takes 1-3 days, and one thing is for sure: you will get to know your product from a completely different side.

An operator thinks in zones, a manufacturer thinks in categories.

There are two ATEX directives: Operator directive 1999/92/EG andproducer directive 2014/34/EU.

I support you in choosing the right category (1,2 or 3)and its impact on your customers (possible zones for operators).

The electrical equipment of the machines is carried out in accordance with EN 60079-14. This standard actually comes from the scope of the Operator Directive 1999/92/EC and is nevertheless applicable in the manufacturing process of the machine. EN 60079-14 places requirements on e.g.

  • Avoidance of ignitable sparks (PA, PE, electrostatics, light metals, etc.)
  • Requirements for cables and wires
  • Requirements for intrinsically safe circuits
  • Use of cable/wire entries
  • Requirements for electric drives (Ex e, Ex d, Ex t, etc.)

The manufacturer of an ex-product must keep the technical documentation up to date. This is another reason why a documented process (procedure instruction) is required for certified manufacturers (Annex IV or VII). This makes sense in general and should also be part of “Internal Production Control” (Annex VIII). It is always important to have effective change management and to ensure compliance with certificates (EU type examination). We will gladly assist you in updating your technical documents, of course also against the background of your certificate. The technical documentation consists of:

  • General description of the product
  • manufacturing drawings
  • drawings
  • Documentation of components, assemblies, circuits, etc.
  • List of applied harmonized standards Reference
  • Tests
  • Used (calibrated) measuring devices
  • Test reports
  • List of approved suppliers
  • EU Declaration of conformity
  • Manual
  • Maintenance / installation instructions
  • Type plate, etc. CE/EX-Marking
  • Procedural instructions, work instructions, forms, checklists

For manufacturers there are different methods (modules) of monitoring by a notified body.

ANNEX IV

(Cat. 1)

MODULE D: CONFORMITY TO THE MODEL BASED ON A QUALITY ASSURANCE RELATED TO THE PRODUCTION PROCESS
ANNEX V

(Cat. 1)

MODULE F: CONFORMITY TO THE MODEL BASED ON A PRODUCT TEST
ANNEX VI

(Cat. 2)

MODULE C1: CONFORMITY TO THE MODEL BASED ON INTERNAL MANUFACTURING CONTROL WITH MONITORED PRODUCT CHECKS
ANNEX VII

(Cat. 2)

MODULE E: CONFORMITY TO THE MODEL BASED ON THE QUALITY ASSURANCE RELATED TO THE PRODUCT

If you choose Annex IV or VII, you need an ATEX quality management system. If you pass the audit, you will receive a Quality assurance notification (QAN).

In the IECEx Equipment Scheme, there are only audits possible (except for single unit verification). You will get a “Quality Assessment Report” (QAR).

In both cases, the basis is ISO 80079-34, based on ISO9001.

The tasks of an ex-authority are complex and challenging. In ISO 80079-34 an ex-authority is mandatory. So, if you want to have an audit accordance with Annex IV or VII of the ATEX Directive 2014/34 / EU or even have to do so in the IECEx, then you need this important key function in your company. Gladly I advise you here to all essential questions!

For further information you will find a professional article here!

The term “assembly” does not exist in ATEX Directive 2014/34/EU. There these are described as “combined devices”.

The term “assembly” is only defined in the ATEX guidelines. Assemblies are placed on the market as:

  • Fully specified combination of parts
  • Various combinations possible (modular system), not necessarily assembled by the manufacturer
  • Determination of conformity by checking that all components meet the conformity requirements
  • Consideration of the risks in the worst case of the combinations

If no ignition hazard can be identified in the systemic context of the assembly, it is not absolutely necessary to undergo a new complete conformity assessment procedure. The standard “DIN IEC/TS 60079-46” is highly recommended.

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