Additive manufacturing and the rules: why a printed part is not a standard part – and when that does not matter

The product standard does not know the product form

For steel flanges, EN 1092-1 refers to forgings to EN 10222, castings to EN 10213 and plate to EN 10028. EN 10253 makes elbows, tees and reducers from pipes and plate. EN 10216 and EN 10217 are pipe standards – seamless rolled, longitudinally welded. In none of these standards does an additively manufactured product form occur. The consequence is simple and hard: a printed flange is not a flange to EN 1092-1, even when dimensions, bolt circle and material number match. It may be called that, but it may not be certified as that, and in a piping system to EN 13480, which refers to the product standards, it is not provided for without a separate proof. For purchasing this means: whoever orders a “flange to EN 1092-1” receives a forged or cast part – and exactly that lies in stock.

Pressure Equipment Directive: three routes for the material, today only one passable

Annex I No. 4 of Directive 2014/68/EU demands one of three proofs for the materials of pressure-retaining parts: conformity with a harmonised standard, a European approval for materials (Article 15, issued by a notified body) or a particular material appraisal (PMA). For metal powder and the printed material condition there are no harmonised material standards and so far no European approval; the third route remains. A particular material appraisal assesses powder, process, heat treatment and test specimens for exactly this part at exactly this manufacturer – it is not a standard that anyone can use, but a piece of work per case. Added to this is the conformity assessment of the pressure equipment itself, in whose category the part falls. Certified manufacturers exist: in 2020 KSB was the first to receive TÜV SÜD certification for the additive manufacturing of components under the Pressure Equipment Directive – for powder bed fusion with stainless steels, nickel-base and iron-base powders to EN 13445-4. That shows the route and its effort at the same time.

The additional requirements by which an inspector assesses a printed pressure part are set out in Germany in the pre-standard DIN/TS 17026 (October 2020, 70 pages): material and process qualification, testing, documentation. At European level the draft E DIN EN 13445-14 has been available since January 2025 (201 pages) – the future harmonised standard for additively manufactured pressure equipment. As soon as it is published, the presumption of conformity replaces the particular material appraisal for what it covers; until then the appraisal remains. AD 2000 as the German body of rules knows the route via material testing analogously.

What a certificate to EN 10204 attests – and what it does not

EN 10204 regulates the types of inspection documents independently of the product. An inspection certificate 3.1 can therefore also be issued for a printed part: it attests the results of the agreed tests – analysis, tensile test, hardness, whatever was ordered. What it does not attest is conformity with a product standard, when there is none. The inspector who reads the certificate must therefore decide for himself whether the attested values are sufficient for the service – and whether the test direction, the heat treatment and the specimen location match the component. For the forged standard part, the standard takes this work off his hands. More under Certificates to EN 10204.

ASME, API and the classification societies

In the ASME world, the criteria document PTB-13 (2021) laid the foundation; Code Cases have grown out of it – for powder bed components in Section I and, with Code Case 3020, for wire arc deposition of pressure-retaining parts, qualified to Section IX. API Std 20S (2021, second edition 2025) lays down for oil and gas how additively manufactured metal parts are qualified and tested by criticality level – that is what an operator will demand for a printed spare part. DNV-ST-B203 (2025) does the same for shipbuilding and offshore from the viewpoint of classification. Whoever works between the worlds of rules finds the comparison in our topic Standards.

Drinking water: an open status

The assessment basis of the German Environment Agency (UBA) for metallic materials in contact with drinking water (§ 15 Drinking Water Ordinance) is a positive list of materials by their chemical composition, tested in the migration test – it names no manufacturing process. Whether an additively manufactured component made of a listed material counts as conforming is therefore neither expressly covered nor excluded; microstructure, surface and residual porosity of the printed condition are not considered in the assessment. Until someone regulates this, there is neither an approval for drinking water components from the printer nor a route we could recommend.

The normative traffic light per component class

The matrix summarises what is derived on this page: standard parts red (no standard part, no approval without appraisal), special parts and valve bodies yellow (particular material appraisal, manufacturer qualification), manufacturer parts without a product standard and repair green. The technical traffic light is on the page Metal and steel; both together are shown in the suitability matrix.

Further reading

This topic: Additive manufacturing in piping · Processes and materials · Metal and steel: component classes · Suitability matrix · Enquiry helper for special parts.

From our range: Materials · Certificates to EN 10204 · Test methods · Guide to standards · Flanges · Valves.