From the ASME Stamp to CE Marking: What Changes in Welding and NDT to Comply with the PED

BY DAN YAMASHITA · ASNT/PCN LEVEL III · IWE · SIMPLENDT · JUN 8, 2026 · 12 MIN READ

A recurring scenario in Brazilian pressure equipment and boiler shops: the company holds an ASME stamp, consolidated WPSs and PQRs, welders qualified to Section IX and a mature NDT program — and then signs a contract to export to Europe. The inevitable question comes up in the very first meeting with the European client: "does all of this count towards CE marking?". The short answer: not automatically. And understanding exactly what changes — and what does not — is the difference between a project that moves forward and one that stalls at the audit.

This article is the general map. It walks through the three pillars where the ASME world and the PED/EN/ISO world diverge — welding procedure qualification (WPS/PQR), welder qualification and nondestructive testing of the equipment — and shows what usually needs to be redone. Each pillar has its own dedicated, deeper article; the goal here is to give the overall picture and avoid the most common confusions.

ASME Is Not CE: Why Credentials Do Not Transfer on Their Own

The CE marking is not a quality seal — it is a legal declaration that the equipment meets the Essential Safety Requirements of the applicable directive, in this case the Pressure Equipment Directive 2014/68/EU (PED). The PED's central mechanism is the presumption of conformity via harmonised standards: when you use the EN/ISO standards published in the Official Journal of the European Union, you are presumed to have met the requirements they cover. For welding and NDT, those harmonised standards belong to the EN ISO family — not the ASME BPVC.

That is why an ASME qualification, on its own, does not confer presumption of conformity with the PED. Mind the precise wording: this is not a case of "ASME doesn't count". ASME is a robust, globally respected technical code, and there are routes that admit materials and solutions outside the harmonised set (for example, the European Approval for Materials or a Particular Material Appraisal). The point is that ASME is not the automatic harmonised path to CE marking — and nearly everything in the PED is built on the EN/ISO framework and on a third party formally entering the process.

The Map of the Two Worlds: Who Approves What

The biggest structural difference is not in any single standard, but in who validates the work. In the ASME world, responsibility rests with the manufacturer, accompanied by the Authorized Inspector (AI) tied to an Authorized Inspection Agency. In the PED world, depending on the equipment's risk category, a third party formally enters the picture — the Notified Body (NB) and/or the RTPO (Recognised Third Party Organisation) — as early as the qualification stage, before the product even exists.

The breakdown by category, under Annex I of the PED, is precise and worth memorising:

• Welding — Section 3.1.2: for Category II, III and IV equipment, welding procedures and welder qualifications must be approved by a competent third party which, at the manufacturer's discretion, may be a Notified Body or an RTPO.
• NDT — Section 3.1.3: for Category III and IV equipment, NDT personnel for permanent joints must be approved by an RTPO (a third-party organisation recognised under Article 20). Here, the Notified Body does not substitute for the RTPO. Visual examination (VT) falls outside this specific requirement, per Guideline F-07.

In short: for welding, NB or RTPO; for NDT (Cat III/IV), specifically an RTPO. The distinction is subtle and frequently confused — including in technical material circulating in Brazil.

Equivalence Dictionary: ASME → PED / EN / ISO

The table below is the summary you can paste on the first page of a transition plan. It maps each pillar of the quality program between the two worlds and flags what usually requires rework.

Pillar 1 — Welding Procedure Qualification (WPS/PQR)

In ASME, the logic revolves around Section IX: a WPS supported by a PQR, with essential, nonessential and supplementary essential variables, and groupings by P-Number (base metal), F-Number and A-Number (filler metal). In the European world, the equivalent is EN ISO 15614-1, where a pWPS is validated by a welding procedure qualification record (WPQR), and base metals are grouped according to ISO/TR 15608.

Three differences deserve attention. First, the 2017 edition of ISO 15614-1 introduced two levels: Level 2, the default when the contract or application standard specifies nothing, with a larger extent of testing and more restrictive qualification ranges; and Level 1, aligned with the ASME Section IX approach, with fewer tests. Qualifying to Level 2 also covers Level 1, but not the other way around. Second, the extent of testing tends to be larger under ISO: beyond tensile and bend tests, Level 2 adds macro examination and, as applicable, hardness testing (required with exceptions) and impact testing (which depends on thickness, material and the application's impact requirements) — so avoid the generalisation that "ISO always requires hardness and impact". Third, third-party approval (NB or RTPO) for Categories II, III and IV is part of the process, unlike the ASME model.

Precision matters here — and it comes from the European Commission itself. PED Guideline F-12 addresses ASME Section IX by name: it recognises that Section IX, on its own, does not sufficiently cover some properties required for certain applications — it cites impact testing in the heat-affected zone (HAZ) and hardness testing — and that it does not require the tests to be performed under the responsibility of a third party. The good news is the equivalence mechanism: you do not need to repeat the tests your ASME PQR has already established, provided the evidence is traceable and accepted by the third party; the missing properties are added to the test program — frequently HAZ impact testing, hardness testing and/or macro examination, depending on material, thickness and application. Your ASME records are leveraged, not discarded — but they must be supplemented and formally approved.

The practical caution is to bring the NB/RTPO in early. "Under the responsibility of the third party" does not necessarily mean the NB or RTPO auditor must perform every test with their own hands; practical tasks can be carried out by a competent laboratory or personnel, provided the program is accepted and the third party takes ownership of the approval. But if the ASME coupon has already been cut up for destructive tests and there is no verifiable record of an NDT examination required by EN ISO 15614-1, the third party may have no basis to accept equivalence. In that case, the solution stops being a simple documentary supplement and may turn into a new qualification coupon welded under a program accepted by the third party. It is not redoing for the sake of it; it is proving equivalence. When the evidence does not exist, redoing may be the only defensible way out.

Pillar 2 — Welder Qualification

Welder performance qualification also runs on different standards: ASME Section IX (WPQ) on one side, EN ISO 9606-1 on the other. The qualified variables look similar — thickness, diameter, position, process, material groups and consumable — but two differences have major practical impact.

The first is validity. Under ASME, the qualification remains valid as long as there is continuity in the process, with a record every six months. Under ISO 9606-1, the certificate has an expiry term and depends on periodic confirmation (a supervising signature every six months) — and the revalidation route varies with the conditions of the manufacturer's quality system. The second is, once again, the third party: for Categories II, III and IV, the welder qualification must be approved by an NB or RTPO. In practice, the problem usually lies less in properties such as hardness or impact — those belong to the WPQR — and more in how the welder's qualification is framed: ranges, validity, periodic confirmation, certificate format and approval against the ISO framework. Many ASME IX qualifications end up needing to be issued or re-approved to EN ISO 9606-1 to cover actual production and enter the technical file without reservations.

Pillar 3 — NDT and Equipment Testing

Here, three layers change at the same time: the personnel, the methods and the acceptance criteria.

On personnel, the contrast is the one we covered in the SNT-TC-1A guide: the ASNT model is employer-based, while Europe normally works with central, independent certification under EN ISO 9712, or an equivalent qualification individually assessed and approved by an RTPO for Categories III and IV. On methods, Section V gives way to the specific EN ISO standards — EN ISO 17636 for radiography, 17640 for ultrasonic testing, 17638 for magnetic particle, 3452 for penetrant testing — which normally forces a rewrite of the NDT procedures.

The acceptance criteria follow a different logic. In ASME, the criteria are embedded in the construction code. In the EN/ISO world, the quality level is defined by ISO 5817 and translated into an acceptance level per method via ISO 17635. For example, as a general baseline, ISO 5817 quality level B corresponds to: RT (ISO 10675-1) acceptance level 1, UT (ISO 11666) acceptance level 2 and MT/PT (ISO 23278/23277) acceptance level 2X — always confirming the applicable product standard, contract and ITP. Note that the same quality level becomes different numbers in each method — which is why there is no single "acceptance level".

Even fine details diverge, and they surface in audits. A concrete example: in radiographic IQI selection, ASME Section V bases the choice on the nominal single-wall thickness plus the estimated weld reinforcement when present; ISO 17636-1 uses the thickness t or w of the wall(s), depending on the technique, without adding the reinforcement as the normal basis, and in the double-wall double-image (DWDI) technique it adopts w = 2t. These approaches lead to different IQIs for the same joint — the kind of divergence that needs to be right in the procedure, not discovered during the Notified Body's review. That is the subject of the dedicated NDT deep dive: ASME V vs EN ISO in NDT — what changes in the procedure, the report and PED approval.

Caution: Three Different “Levels” That Are Not the Same Thing

A good share of the confusion in transition projects comes from a single word: "level". There are three different scales in play, and they have no direct relationship to one another:

• ISO 15614-1 Level 1 / Level 2 — the extent and rigour of the welding procedure qualification. Level 2 is the default; Level 1 is the reduced route, aligned with ASME.
• ISO 9712 Level 1 / 2 / 3 — the competence of NDT personnel (who performs, interprets and evaluates the tests).
• Acceptance level 1 / 2 / 3 — the severity of the test's acceptance criteria (ISO 10675-1, ISO 11666 etc.), derived from the ISO 5817 quality level.

Whenever you write "level X" in a document, make explicit which scale you mean. In a WPQR, "level 2" is the procedure qualification; in an NDT report, "level 2" may be the acceptance criteria or the inspector's qualification — different contexts, different standards.

Checklist: From the ASME Shop to CE-Marked Equipment

For a manufacturer already operating under ASME and aiming for the European market, the practical path usually follows this order:

• Classify the equipment by category (I to IV) — this defines everything else, including when the third party comes in.
• Select the conformity assessment module and engage a Notified Body where applicable.
• Review your ASME IX welding procedures against EN ISO 15614-1: leverage equivalent evidence, but supplement the typically critical properties — such as HAZ impact testing, hardness testing and/or macro examination — under NB/RTPO responsibility for Categories II, III and IV.
• Review your ASME IX welder qualifications against EN ISO 9606-1: ranges, validity, periodic confirmation and third-party approval for Cat II+; in practice, many need to be issued or re-approved within the ISO framework.
• Adapt the NDT program: procedures to the EN ISO standards, criteria via ISO 5817/17635, and personnel to EN ISO 9712 — or an equivalent individually approved by an RTPO — for Categories III and IV.
• Compile the technical file including procedure, welder and NDT personnel qualification records, and appoint an authorised representative in the EEA.

The encouraging part: the discipline of those who already live under ASME — material traceability, document control, a culture of procedures — is exactly what makes the transition faster. What changes is the normative framework and the formal entry of the third party. SimpleNDT works on this bridge mainly where NDT is involved: procedures, acceptance criteria, personnel qualification, evidence for the NB/RTPO and the technical interface between ASME and EN ISO when welding needs to be compared against the European framework. Dan Yamashita is PCN Level 3 (ISO 9712) with RTPO-approved NDT personnel status under the PED, and works in both worlds. See the PED compliance services and ASME audit services.