Harmonised standards are defined as technical specifications, adopted by a recognised standardisation body, and approved and published by the EU Commission for repeated or continuous applications.

A harmonised standard in this context can be a harmonised product standard for an item of pressure equipment or an assembly which may be CE marked e.g. EN 13445 Series. It could also be a harmonised supporting standard, that contains technical data clearly indicating the field of application e.g. EN 764 series.

The role of harmonised standards in complying with applicable essential requirements identified by a manufacturer — a generic philosophy for cases where a manufacturer needs to identify applicable essential requirements:

1. All essential requirements identify, listed in the relevant legislations
2. Carry out a risk assessment to determine which applicable essential requirements to be complied with
3. Selection of technical specifications (harmonised standards or other specifications) to comply which applicable essential requirements

Where a harmonised standard covers only part of the essential requirements identified as applicable by a manufacturer or only certain aspects thereof, he additionally has to use other relevant technical specifications or develop solutions in accordance with general engineering or scientific knowledge laid down in engineering and scientific literature in order to meet the essential requirements of the legislation in question.

Note 1: Harmonised standards never replace legally binding essential requirements. A technical specification given in a harmonised standard is not an alternative to a relevant essential or other legal requirement but only a possible technical means to
comply with it.

Note 2: Harmonised standards may also apply in whole or in part to several pieces of legislation

Note 3: When applying a harmonised standard, it can be assumed that the corresponding requirements listed in Annex ZA are fulfilled with the legal provisions mentioned there (presumption of conformity)

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What are harmonised standards? (Formal requirements and validity)