The Written Practice Is the Only Document That Certifies Anyone in Your Shop

What the written practice is, and what it is not

A written practice is an employer-issued document that states how your company qualifies and certifies its own NDT personnel. It is not a training certificate, not a résumé file and not a copy of SNT-TC-1A with your logo on it. SNT-TC-1A is a recommended practice: it supplies a framework of guidance which the employer is expected to adapt, and the written practice is the record of every adaptation you made and every guidance value you chose to accept.

That distinction matters because the document, not the standard, is the audit baseline. If your practice sets 40 hours of training for UT Level II where the recommended table suggests a different figure, an auditor holds you to your 40 hours. If your practice says nothing about interruption of activity, the auditor does not import a rule for you — instead they record a gap, because the practice fails to control a situation your shop demonstrably encounters.

The second thing a written practice is not: a document owned by the quality manager alone. Certification is a technical act. The person who approves the procedures a technician works to, and who grades the practical examination on which certification rests, is the Level III named in the practice. A quality system can administer the files, but it cannot manufacture the technical authority behind the signature.

The clauses a fabrication shop's practice has to answer

Start with scope: name every method actually performed on your floor, at every level, including visual examination and including any method performed only occasionally. Shops routinely omit VT because it feels like part of welding inspection rather than NDT, then find themselves accepting welds on a signature nobody certified for the method. The same gap appears with methods introduced by equipment purchase — a phased array unit arrives, gets used on a thick-wall job, and the practice still lists conventional UT only.

Then the qualification structure per method and level: training hours with a documented course outline, experience hours that are method-specific rather than lumped, and the three examinations — general, specific and practical — with their individual pass marks and the composite score rule. The arithmetic of composite scoring is a live audit issue. A candidate can clear each individual paper and still miss the composite requirement, and the file has to show the calculation rather than a bare conclusion.

Finally the housekeeping that decides most findings: annual near-vision acuity and colour contrast differentiation, the recertification interval and its mechanism, what happens after an interruption in method activity, suspension and reinstatement, the retention period for records, and — the clause most often missing — the identity and credential of the Level III who signs. That name is the load-bearing element of the entire document.

SNT-TC-1A, CP-189, ISO 9712 and NAS 410 are not interchangeable

SNT-TC-1A and CP-189 are both employer-based schemes: your company certifies your own people. The difference is force. SNT-TC-1A is guidance you adapt; CP-189 is a standard with mandatory minimums, required topical outlines drawn from ASNT CP-105, and a requirement that your Level III hold an ASNT Level III certificate rather than a certificate you issued internally. A shop drafted against SNT-TC-1A that accepts a nuclear-adjacent order carrying 10 CFR 50 Appendix B and NQA-1 flow-downs will usually find CP-189 sitting underneath it.

ISO 9712 is a different animal entirely: certification is issued by an independent certification body, not by the employer, and the employer's role reduces to authorisation to operate. You cannot satisfy an ISO 9712 requirement by writing a better written practice, and you cannot convert an employer certification into an ISO 9712 one by declaration. Shops exporting into European construction regimes discover this late, usually at the point of a Notified Body review.

NAS 410 governs aerospace NDT personnel and adds requirements around the outside agency, the responsible Level III and specific method training that neither SNT-TC-1A nor CP-189 impose. If any part of your shop touches airframe, engine or aerospace ground support work — including the occasional repair order that arrives through a maintenance operator — a general-industry practice is not adequate and a Nadcap audit will say so.

How an auditor actually samples a personnel file

The document review takes twenty minutes. The finding comes from the sample. An experienced auditor picks two or three technicians — usually one long-serving, one recent hire, one who works a method the shop performs rarely — and traces each certification backwards to primary evidence rather than forwards from the certificate.

Training hours: is there a course outline, a roster, a sign-in sheet and an instructor whose own qualification is on file? Experience hours: are they method-specific, and do job tickets or timesheets from the claimed period show that technician on that method? Examinations: are the graded papers present with the answer key, and does the composite arithmetic reproduce? Practical: which specimen was used, what flaws does it contain, who characterised them, and where is the specimen now? Vision: dated within twelve months, examiner named, chart identified?

Then the signature. The auditor checks the date on the certification against the validity window of the Level III who signed it, and against the version of the written practice in force on that date. A certification signed by an individual whose own credential had lapsed, or who was not the named Level III at that moment, is not a paperwork problem. It voids the certification, and with it the standing of every report the technician issued afterwards.

The findings that recur in shop audits

Floating edition references. A practice citing "SNT-TC-1A, latest edition" hands the auditor the right to hold you to the newest published edition, including tables you have never read. Name the edition and the year, and revise deliberately when you decide to move.

Photocopied near-vision charts. Jaeger-type charts depend on printed type size; a photocopy or a screen render at arbitrary scale is not the test. The finding is trivial to close and embarrassingly common, and it is usually accompanied by the second half of the problem — the test administered by the technician's own supervisor with no record of the chart, the distance or the correction worn.

Limited certification used as full scope. A technician certified for a narrow application — one geometry, one thickness range, one product form — appears on reports covering work outside that boundary. Then the subcontractor gap: agency technicians brought in for a surge, working under your reports, never evaluated against your practice and never accepted through a documented subcontractor approval. And the quiet one: a method added by purchase order rather than by revision, so the equipment is on the floor months before the document acknowledges it exists.

Where the practice drifts between audits

Drift is not negligence; it is the normal consequence of a shop being busy. The practice is written once, usually around a certification milestone such as a U stamp application or an ISO 9001 registration, by someone who then leaves the project. Everything after that is production.

The predictable drift vectors are people and scope. People: the named Level III changes employer, retires or simply stops being reachable, and nobody updates the document because certifications are not due that quarter. Technicians rotate off a method for eighteen months during a slow period and rotate back on with no interruption review. New hires arrive holding certificates from a previous employer, and those certificates get filed as though they transferred — they do not; employer-based certification does not travel, and the receiving employer must certify against its own practice.

Scope: a new customer brings a code you have not worked to, a new alloy brings a method you have not performed, a new fabrication technique brings acceptance criteria your procedures do not cover. Each of those is a small decision made correctly on the floor and never reflected in the controlling document. Six of them stacked together is a failed audit.

How ASME, AWS and client regimes move the definition of adequate

Under ASME construction, Section V Article 1 requires that NDE personnel be qualified in accordance with the employer's written practice based on SNT-TC-1A or CP-189, and Section VIII Division 1 relies on that chain when the Authorized Inspector verifies examinations. The pressure point in an ASME shop is usually not the practice's wording but the link between certification, the approved procedure and the specific examination record on a specific vessel.

AWS D1.1 work introduces a separate expectation. Structural ultrasonic testing under D1.1 uses its own indication rating arithmetic — the rating d equals the indication level a, minus the reference level b, minus an attenuation factor c derived from sound path — and an operator whose qualification never covered that method of evaluation will produce ratings that shift by whole acceptance classes. A practice written entirely around ASME weld examination has to be extended before the first structural order, not after it.

Client regimes then layer on top. An end user's supplier quality manual may invoke CP-189, an aerospace flow-down may invoke NAS 410, a nuclear-adjacent order may bring NQA-1, an inspection body relationship may bring ISO/IEC 17020, and an ISO 9001:2015 registrar will read the practice as the competence evidence required by clause 7.2. Adequate is defined by whichever of these is strictest on your busiest contract.

What a Level III does when developing or repairing the practice

The work starts with an evidence sample rather than a rewrite, because the fastest way to find out what a practice actually controls is to audit three files against it exactly as a client would. That sample tells you whether you have a document problem, an execution problem or both — and those have completely different remedies.

Development then covers the document itself, the method and level structure, examination material that traces to a topical outline, practical specimens characterised and brought under custody, the vision and interruption controls, and the record retention rule. Alongside it sits the procedure set the technicians actually work to, because a written practice that certifies people against procedures nobody approved is only half a system.

Atlantis provides this as an ASNT Level III service: written practice development or repair, procedure development and qualification, examination and practical material, certification within the practice, technical representation during client and registrar audits, and independent review of inspection data. Work is scoped to your methods, your codes and your customers' flow-downs, and pricing is quoted on request after a scoping call — write to info@atlantisndt.com to arrange one.

Request a consultation