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Why examine pressure equipment in assemblies?

Updates from Switzerland

Why examine pressure equipment in assemblies?

Because of investments or process changes, plant operators often become manufacturers of pressure equipment installations (EKAS 6516). Depending on the hazard categories, it may be necessary to go through a conformity procedure with notified bodies. Whole assemblies come then into focus, which should comply with Directive 2014/68/EU. In this frame, often the individual testing of the assembly per Module G is important. What is it all about?

September 2018

The Swiss Regulations for the Prevention of Accidents and Occupational Diseases (VUV) and the Pressure Equipment Ordinance (DGVV) contain requirements which oblige the employer to take measures for the use of pressure equipment. A proven verification document for this is the Declaration of Conformity, which is issued by pressure equipment manufacturers.

Due to economic interests, declarations of conformity between Switzerland and the European Union are administrated by bilateral agreements. This enables facilitated trade of goods based on harmonized conformity assessment as proof for the performed safety tests.

A CE mark known in the European Union for this purpose is not necessarily mandatory in Switzerland, but often used in Switzerland.

If a product is intended to be placed on the European market, including Switzerland, the manufacturer of a pressure-related product has the obligation to use the product conformity procedure according to the Pressure Equipment Directive 2014/68/EU. In principle, the Pressure Equipment Directive 2014/68/EU applies to an overpressure of more than 500 mbar, be it for devices themselves or their combination into an assembly. Pressure equipment can be containers, piping but also pressure-retaining equipment or their construction in the form of an assembly. The application of the directive is not mandatory if the pressure equipment is out of its scope.

Conformity assessment diagrams assign hazard categories to affected objects: categories I to IV, where IV represents the highest hazard category. Should none of these hazard categories apply, then the product may be designed and manufactured in accordance with applicable ‘Sound Engineering Practice’. Pressure equipment or assemblies based on good engineering practice may not be CE marked.

The higher the hazard category, the higher the production-related effort, the qualification requirements of the manufacturer or the need to involve an accredited body following the Directive 2014/68/EU. The conformity assessment procedure according to Module A corresponds to an in-house production control which does not require a Notified Body (Table 1).

Globally, it can be seen that in mass production, production can be made more flexible and independent of third-party requirements. For this purpose, the manufacturer requires higher quality qualifications and these are checked by notified bodies in an exemplary and recurring manner.

In contrast, the examination method according to Module G is expressly a very flexibly oriented conformity assessment procedure, in which the production of unique equipment is accompanied by notified bodies. The conformity is attested on a product-specific basis. This test procedure is used in particular by process operators since every system combination represents a single piece.

In summary, it can be stated that process operator owners have to design systems that are set up together as an assembly in such a way that, quoting the Pressure Equipment Directive 2014/68/EU:

  • the interconnected components are reliable and suitable for their operating conditions
  • ensuring proper installation of all components and their proper integration and grouping within the assembly

With suitable risk analyses, many operators accurately comply with these required essential safety requirements with appropriate measures. According to the relevant laws, these new procedures must be monitored and checked by independent, accredited expert organizations, depending on the degree of hazard (Figure 1).

Figure 1: Life Cycle Services of TÜV SÜD Schweiz AG

If is still not clear "Why examine pressure equipment in assemblies?" or you are not sure whether you, as the operator, are also the manufacturer or distributor of your system/installation, we be pleased to answer your questions. Please contact us.


Orkun Cati

[email protected]

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