The written practice that controls every NDT certificate in a steel plant

A written practice is a controlled document, not a folder of certificates

The written practice is the single document that authorises every NDT certificate your plant issues. It is not a certificate file, not a training matrix, and not a procedure. It is the employer's own statement of how personnel are trained, examined, certified, recertified and, when necessary, decertified, written against ASNT SNT-TC-1A or ANSI/ASNT CP-189 and signed by a Level III. Every certificate in the drawer derives its authority from it. If the document is wrong, every certificate downstream of it is wrong too.

SNT-TC-1A is a recommended practice, which means it carries no force on its own. It becomes binding the moment a construction code, a purchase order or a customer specification invokes it. ASME Section V, for example, requires personnel to be qualified in accordance with the employer's written practice based on SNT-TC-1A or CP-189, which is how a recommended practice acquires teeth on a pressure boundary weld in a plant powerhouse. The same mechanism operates through customer specifications on structural and mechanical work that no pressure code touches.

Because it is a controlled document it needs a revision block, a distribution record, and a demonstrable link to the procedures it references. A practice that cites procedure numbers which were superseded three revisions ago is a finding on its own, before the auditor even reaches a technician file. Treat it the way you treat a quality manual, not the way you treat a poster on the wall.

The clauses that must be present, and the numbers behind them

At minimum the document must state the standard and edition adopted; every deviation from that standard; the methods and levels the employer certifies; the training hours required per method and level; the experience hours required in the method and in NDT overall; the composition, question count and passing score for general, specific and practical examinations; the compositing rule for a final grade; the near-vision and color contrast requirements; the certification and recertification intervals; the interruption of duties rule; and the identity and authority of the Level III.

The numbers themselves come from the tables in the standard you adopt, and they are not interchangeable between methods. Ultrasonic testing carries far heavier training and experience minimums than magnetic particle or penetrant, which is exactly why UT is the method where undercooked certifications concentrate. Copy the tables in full, state clearly whether hours credited from a previous employer are accepted and how they are verified, and record the arithmetic used to combine general, specific and practical scores. Auditors recalculate composite scores. They find errors.

One clause worth writing carefully is the deviation list. SNT-TC-1A expects the employer to modify it to suit the work, but it also expects those modifications to be documented rather than silently applied. A practice that reduces an examination question count without saying so reads, on audit day, as a practice that was not followed. A practice that reduces it and says so on the cover page reads as a practice that was engineered.

Who owns the document, and who is allowed to sign a certificate

The employer owns the written practice. Not the Level III, not the consultant, not the software vendor. This distinction matters because it determines what happens when the Level III leaves. If the practice names an individual, and that individual departs, certificates cannot continue to be issued under their signature. Auditors do check signature dates against employment dates, and it is one of the more damaging findings available, because it retrospectively taints everything signed after the departure.

The practice must therefore say who the Level III is, what their own certification rests on, and what happens when they are unavailable. Where an outside Level III is engaged, which both SNT-TC-1A and common industrial practice accommodate, the document must be explicit that the employer retains responsibility for the programme and that the outside Level III exercises defined technical authority within it. The contract and the practice should agree with each other. Frequently they do not.

Verify the Level III's own certification the same way you would verify a technician's. An outside Level III whose ASNT certificate lapsed eighteen months ago has been signing invalid approvals for eighteen months. This is not hypothetical; it is one of the more common findings when a plant changes consultants and someone finally looks at the file.

The backwards walk: how an audit actually samples the document

A competent auditor never reads the practice cover to cover first. They open it, note the standard and edition, then close it and go to the shop floor. They pick a technician who is working, ask what procedure they are running, then ask to see the certification that authorises it. From there the walk goes backwards: certificate to examination papers, papers to answer key and grading, grading to training records, training to hours, hours to the table in the practice, and the signature to the Level III named in the practice.

Each link is a place to fail. Missing answer keys are common because someone destroyed them for exam security without a retention rule. Practical examination records are often a single line saying "pass", with no checklist, no specimen identification and no record of what discontinuities the candidate was expected to find. Experience logs are frequently reconstructed from memory in the week before the audit, which is visible to anyone who reads them. Vision tests lapse quietly because nobody owns the tickler.

The strongest defence is to run the backwards walk on yourself, on two or three files, twice a year. It takes an afternoon. It finds the same things the auditor would find, at a point when you can still fix them without a corrective action report attached to a customer's name.

Scope drift: the failure mode specific to steel and primary metals

Steel and primary metals plants rarely fail on paperwork discipline. They fail on scope. The practice was written for a defined set of work, usually weld inspection during a capital project or a fabrication shop's product line, and then the plant's actual inspection load grew sideways into maintenance and reliability work that the document never contemplated. Nobody revised the practice, because nobody experienced the growth as a change.

The result is technicians certified in a method but running techniques and applications the practice does not describe. A UT Level II certified against a weld examination procedure is running corrosion thickness grids on hot blast ducting. An MT Level II certified for fabrication welds is inspecting refractory anchor attachments on a live furnace shell during an outage. In each case the method matches and the application does not, and the acceptance basis is completely different: one is a code weld acceptance standard, the other is a remaining wall or fitness decision with no construction code behind it at all.

Drift also runs through the procedure library. Procedures written for the capital project stay in force for a decade, referencing an equipment model that left the plant, a couplant that is no longer stocked, or a calibration block that cannot be located. The practice points at those procedure numbers. Cleaning this up is unglamorous and it is the highest yield work available in most metals plants.

Furnaces, ducting and abrasion: what the practice actually has to authorise

The characteristic inspection load in steel and primary metals is high temperature, abrasive and largely outside the pressure codes. Reheat furnace and stove shells, hot blast ducting, sinter and pellet plant gas paths, electric arc furnace water panels and elbows, ID fan housings, baghouse casings, ladle and transfer equipment, dust collection ductwork downstream of scrubbers. The damage mechanisms are erosion from particulate, thermal fatigue and cycling, oxidation and scaling, creep in the genuinely hot sections, dew point corrosion where flue gas cools past its acid dew point, and refractory anchor failure that removes the thermal protection before anything else shows.

Each of those pushes the practice somewhere it may not go. Ultrasonic thickness on ducting demands a stated retirement basis, and here is the arithmetic trap: outside the pressure codes there is no design minimum thickness to compare against, so someone picks a percentage of nominal. That number needs an engineering basis, whether structural, stiffener spacing, or internal pressure and vacuum excursions, and the procedure should reference it. A survey report full of readings and no retirement criterion is data, not a decision.

High temperature UT is its own discipline and belongs in the practice explicitly. Couplant and probe temperature limits, contact time, velocity change with temperature, and correction of the result. A technician taking readings on a surface at four hundred degrees Fahrenheit with a room temperature velocity setting produces confidently wrong numbers. Similarly, replication, in-situ metallography, portable hardness and positive material identification are routine in metals plants and sit outside most practices' method lists. Either add them as additional methods with their own qualification route, or accept that nobody in the plant is qualified to perform them.

When the client regime redefines what adequate means

The same plant can face three incompatible definitions of an adequately qualified technician depending on who is buying the steel. For general industrial and construction customers, an employer-based SNT-TC-1A or CP-189 certification is the expectation and the practice governs. That is the baseline the document should be written to.

Sell specialty alloy or forged product into aerospace and the regime changes to NAS 410, audited through Nadcap. NAS 410 is stricter about the responsible Level 3, about outside certification of that Level 3, and about the traceability of examinations. It is not a matter of relabelling the existing practice; it is a separate qualification scheme, and running both simultaneously requires the document to be structured so that the aerospace scope is unambiguously segregated from the general industrial scope.

Automotive customers audited under IATF 16949 require personnel performing non-destructive evaluation to be qualified, and customer-specific requirements typically name ASNT or ISO 9712 as the route. Export into the European pressure equipment regime shifts the ground again: for higher-category equipment, personnel performing non-destructive tests of permanent joints must be approved by a recognised third-party organisation, which an employer-based certificate does not satisfy no matter how well written the practice is. That last one surprises people late in a project, when the equipment is built and the paperwork will not clear.

Recertification, interruption of duties, and the myth of the transferable card

Recertification intervals are set by the practice within the limits of the standard adopted, and the standard permits a maximum rather than mandating a fixed period. A plant with a stable, experienced crew can sit at the maximum. A plant with turnover, or with methods used only during outages, should set a shorter interval for the methods that are used least, because that is where competence decays fastest and where the interruption of duties clause bites.

The interruption clause is routinely ignored. A technician certified in radiography who has not performed radiography in two years is, under most practices, no longer current in it, regardless of what the certificate's expiry date says. Outage-driven metals plants have exactly this pattern: intense use of a method for six weeks, then nothing for a year. The practice must define the interruption period and the requalification route, and someone must actually track it.

Finally, the transferable card. Certification is employer-specific. A technician arriving with a card from a service company does not carry certification into your plant, and issuing your own certificate on the strength of theirs without verified training records, verified experience and your own examinations creates a file that will not survive a backwards walk. Credit what you can verify, examine what you must, and document the credit decision inside the practice so it is a rule rather than a favour.

How Atlantis develops and maintains the document

Atlantis works as NDT technical authority: writing or rewriting the written practice, developing and qualifying the procedures it points at, examining and certifying personnel within the practice, and representing the plant on technical questions when a customer or registrar audits the programme. Where a practice already exists, the normal first step is an assessment against the standard and edition your customers actually require, with findings ranked by audit exposure. Nothing existing is discarded; the goal is a document that survives the backwards walk on any file an auditor picks.

For metals plants the work usually extends past the document into the procedure library, because that is where scope drift lives. Thickness survey procedures with a stated retirement basis, high temperature UT with correction rules, refractory anchor and expansion joint inspection, and a clear statement of which additional methods the plant performs and how those people are qualified.

Anoop Rayavarapu holds ASNT NDT Level III certification in multiple methods and is an API 653 Authorized Inspector. To discuss an assessment of your current practice or development of a new one, contact info@atlantisndt.com for a consultation.

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