"Harmonized" European standards

The European Commission refers to European Standards that are produced by CEN, CENELEC, or ETSI under a mandate given by the European Commission as 'harmonized standards' (hEN). In general, these standards support the essential requirements of a New Approach Directive.

Harmonized standards are prepared to verify the compliance of a product with relevant European legislation (Directive, Regulation). EU Commission issues Mandates to CEN for preparation of harmonized product standards.

A harmonized standard may be based on already existing "non-harmonized" European Standard, an ISO standard (existing or under preparation), a suitable national standard or other document.

For more information about Harmonized standards and New Approach Directives

EN standard preparation process


Background information

The technical work is carried out under the overall management of the CEN Technical Board (BT). The BT is reponsible for setting up various technical and project comittees and monitoring the progress of the technical work. It is also responsible for setting up the rules for the development of European standards.

Technical Committees (TC) are established by the BT in order to develop European standards or other normative documents related to specific industries or generic subjects appropriate to the needs of that sector.

In cases where a limited number of standards is needed on a particular subject and in a new area, a Project Committee (PC) instead of a TC can be established. PCs function in a similar way to TCs but they are not allowed to decide on the inclusion of new work items in their programme and they are disbanded once they have finished the standardization work for which they were created.

Technical Committees may set up one or more Working Groups (WG) in order to focus on specific tasks or to provide a draft standard.

For more information see the organization chart.

Currently there are more than 300 active Technical Committees in CEN, about 30 deal with or have at least some relevance to HVAC.

For more information see the Business Operations Support System ”BOSS” pages on CEN website.


The process in a nutshell – for more information see How are standards developed

Once the text of an intended standard has been drawn up by the relevant Working Group (WG), under a Technical Committee (TC), and accepted by that particular TC for approval, it will be sent by CEN to all National Standardization Bodies (NSB) for Public Enquiry.

At this stage the document receives its number and the designation "prEN" (Draft European Standard). Each NSB is obliged to cast its vote and may give general, technical and editorial comments. All comments will be then examined under the responsibility of the relevant TC – in practice by the WG who had prepared the draft, and this WG also prepares the modifications taking into account the comments.

Then the TC approves the text for further processing to CEN, who finally will send the final draft (now called "Final Draft European Standard" or FprEN) for Formal Vote among the NSB's. Again, each NSB is obliged to vote, but at this final stage it is no more possible to change the technical contents of the draft, only minor editorial changes can be made. The vote is weighted (e.g.Germany has 29 votes, Finland 7 votes) – and at least 71% of the votes must be positive to have the standard approved.

Soon after approval the document will be published as European Standard (EN) by CEN, and within 6 months each CEN member has to adopt it as a national standard (this explains why all members are obliged to vote) and withdraw possible conflicting national standards.


Timeframe for the development of European Standards


Timeframe for the development of Technical Reports