Radiographic Testing (RT) Requirements Under ema

Radiation safety sits alongside the technical requirement: the radiographer licence, the area control and the dose records are audited as part of the same programme. ema, enforced by ema, operating as an Entidad de Acreditación under the Ley de Infraestructura.: ISO/IEC 17020 does not require an inspection body's inspectors to hold third-party certification.

An auditor examining RT asks for source or tube, exposure devices, film or detectors, densitometers, IQIs and the survey meters used to control the area. ema is the accreditation body that turns a Mexican inspection firm into one whose dictámenes a regulator will recognise. It accredits unidades de inspección against NMX-EC-17020-IMNC-2014, the Mexican adoption of ISO/IEC 17020:2012, applying ILAC P15 as guidance. Two things routinely trip up foreign firms. First, accreditation alone is not sufficient for regulated work: issuing a dictamen under a NOM also requires aprobación by the relevant dependency, and STPS publishes the directory of accredited and approved units. Second, since the Ley de Infraestructura de la Calidad took effect the statutory term changed from unidad de verificación to unidad de inspección — the activity is unchanged, and ema's own procedures still carry both names.

Source: ema, 'Manual de Procedimientos — Evaluación y Acreditación de Unidades de Verificación (Organismos de Inspección) con base en la norma NMX-EC-17020-IMNC-2014 / ISO/IEC 17020:2012', extracted and read directly, including its definitions of renovación (4.33), testificación (4.44) and vigilancia (4.46) and its surveillance, reevaluation and witnessing intervals; the procedure cites ILAC P15, 'Guía de aplicación de la ISO/IEC 17020 para unidades de Verificación'. Types A, B and C and the accredited-plus-approved requirement from ema's application guides for the same standard and from NOM-020-STPS-2011 clauses 4.41 to 4.43 and 19. Terminology change from unidad de verificación to unidad de inspección under the Ley de Infraestructura de la Calidad, published in the DOF on 1 July 2020; cancellation grounds from Article 59 of that law. Limitation: ema's own website returned HTTP 403 from this environment on 21 August 2026, so the public accredited-body directory at catalogo.consultaema.mx was not consulted and no counts or named accredited firms are stated. Verified 21 August 2026.

Radiographic Testing under ema — procedure, personnel and evidence
Item	What applies	Why it matters
Regime	Entidad Mexicana de Acreditación, A.C.	Enforced by ema, operating as an Entidad de Acreditación under the Ley de Infraestructura de la Calidad; sectoral aprobación is granted separately by the regulating dependency — for pressure equipment under NOM-020, the Secretaría del Trabajo y Previsión Social
Method	Radiographic Testing (RT)	Needs its own procedure and its own qualified personnel
Procedure approval	The employer's Level III, qualified in this method	The signature an auditor traces
Other methods in scope	UT, MT, PT, VT, ET, Thickness measurement	Each needs separate qualification
Renewal	ema's procedure sets surveillance (vigilancia) at 12-month intervals, which may be conducted in the two months before or after the due date. The first surveillance evaluation is performed on site and preferably before 12 months from the accreditation date, with an outer limit of 18 months measured from that date for initial accreditations. Reevaluación must be carried out before the four-year cycle completes, counted from the last reevaluation decided by the relevant evaluation committee or technical opinion commission. Testificación must be repeated within no more than four years of the last witnessing. Renovación — a full re-evaluation against an expiry date — applies where a dependency requires the accreditation to carry one. Under Article 59 of the Ley de Infraestructura de la Calidad, accreditation or approval can be cancelled for issuing documents with false or erroneous information, repeatedly refusing requested services, express renunciation, serious breaches of obligations, or altering issued documents.	Applies to the personnel certification behind this method

Does ema require a separate procedure for RT?

Yes. Every method in scope needs its own written procedure, approved by someone qualified in that method, describing technique, equipment, calibration, scanning or coverage, acceptance criteria and reporting. A single combined "NDT procedure" covering several methods is a finding under every regime that names procedures individually.

Who can approve a RT procedure under ema?

A Level III qualified in RT. Because ema accepts employer-based certification, that Level III may be contracted rather than employed — but their own qualification must cover RT, and an auditor will check that before accepting the signature.

What RT records does a ema audit sample?

The approved procedure, the technician's RT certification on the date of work, and the equipment evidence — source or tube, exposure devices, film or detectors, densitometers, IQIs and the survey meters used to control the area. The auditor works backwards from a finished job, so every item has to reconcile with the report and its stated acceptance criteria.

What is the most common RT finding at audit?

IQI sensitivity not achieved, or radiation area control records missing for the shot. It is a records failure rather than a technique failure — the examination was performed correctly and the evidence supporting it cannot be produced, which under ema is recorded the same way as not having done the work.

Can a technician certified elsewhere perform RT under ema?

Not automatically. Employer-based certification ends when the holder leaves, so the new employer must certify them under its own written practice. Prior training and documented experience transfer as evidence; the certificate itself does not.

What equipment evidence does RT need under ema?

Calibration status traceable to the day of use, covering the instrument and its accessories — probes, cables, blocks and reference standards for ultrasonics; sources and densitometers for radiography. An in-calibration instrument with an out-of-calibration reference block fails the same way as an uncalibrated one.

How do RT requirements differ from the other methods in ema?

Scope, qualification and evidence are method-specific, so the differences are real rather than administrative. ema also covers UT, MT, PT, VT, ET, and each carries its own procedure, its own personnel qualification and its own equipment evidence.

Personnel certification for RT

ISO/IEC 17020 does not require an inspection body's inspectors to hold third-party certification. The body itself defines, documents and verifies competence criteria for each inspection activity, and ema evaluates that system — verifying personnel competence by demonstration during the on-site evaluation and by witnessing real inspections (testificación). That makes an employer-operated competence scheme backed by an outsourced Level III genuinely workable in Mexico, provided it is documented, applied and evidenced. Separately, ema accredits personnel certification bodies against NMX-EC-17024-IMNC, which is how centrally certified NDT personnel exist in Mexico at all. Where a NOM or a client contract names a personnel standard, that sits on top of, not instead of, the 17020 competence system.