BS EN 473-2000 pdf download.Non-destructive testing – Qualification and certification of  NDT personnel General principles.
8.3 Validity
The maximum period of validity of the certificate is five years. The initial period of validity shall commence when all of the requirements for certification (training, experience, success In examination and satisfactory vision test) are fulfilled.
Certification shall become invalid:
a) at the option of the certification body, e.g. after reviewing evidence of unethical behaviour incompatible with the certification procedures;
b) if the individual becomes physically incapable of performing his duties based upon failure of the visual acuity examination taken annually under the responsibility of his employer;
c) if a significant interruption (see 3.25) takes place in the method for which the individual is certificated,
E)9 Renewal
9.1 Upon expiration of the first period of validity and every ten years thereafter, certification may be renewed by the certification body for a new period of five years on production of:
a) written evidence of a satisfactory visual acuity examination taken within the preceding 12 months:
b) documentary evidence of continued satisfactory work activity without significant interruption (see 3.25) in the method and sector for which certificate renewal is sought.
9.2 If the subclause 9.1 (b) criterion for renewal is not satisfied, the individual shall be permitted to attempt recertification.
10 Recertification
10.1 Levels 1 and 2 certificate holders seeking recertification shall meet the criteria of 9.1 (a) and (b) for
renewal and satisfy 10.1.1. In the case of operators carrying out repetitive testing in sectors dealing with
mass products, 10.1.2 may be used instead of 10.1.1; this alternative route will only allow recertification with
a limited scope as defined by the Certification Body.
10.1.1 Successfully complete a practical examination organised to a simplified procedure wtiich demonstrates continued competence within the scope defined on the certificate. This shall include testing test specimens appropriate to the scope of certification to be revalidated and, for level 2, the production of a written instruction suitable for the use of level 1 personnel. If the individual fails to achieve a grade of at least 70% for each specimen attempted and 80% overall (weighted according to the guidance of Table 7), one retest of the whole certification examination shall be allowed after at least 7 days and before 6 months. In the event of failure in the one allowable retest, the certificate shall not be revalidated, arid, to regain certification for that level, sector and method the candidate shall apply for new certification. In this case, no examination exemptions shall be awarded by virtue of any other valid certification held.
10.1.2 Successfully demonstrate, during an audit conducted in the work place by the Certification Body with the employer’s written consent, continued competence in the work performed. The audit shall be carried out by an examiner authorised and appointed by the Certification Body and shall comprise the witnessing of the satisfactory implementation by the certificate holder of a range of tasks covering the scope of the certificate. The examiner shall produce a fully documented report with recommendations regarding limitation of the scope of certification. The extent and scope of the recertification shall be determined by the Certification Body based on this report. A candidate who applies for and does not meet the requirements of 10.1.2 shall be permitted one attempt at recertification under 10.1.1.
10.2 Level 3 certificate holders seeking certification shall meet the 9.1 (a) and (b) criteria for renewal and depending on the choice of the certificated individual, either successfully complete a written examination which includes a minimum of 20 questions on the application of the test method in the sector(s) concerned (at least 4 of which shall require narrative answers which demonstrate an understanding of current NDT techniques, standards, codes or specifications, and applied technology) and, at the option of the Certification Body, a minimum of 5 questions on the requirements of the certification scheme, or meet the requirements of a structured credit system. (given in the normative Annex C). Consequently the certification body shall provide the two possibilities : written examination or requirements for structured credit system. If the individual fails to achieve a grade of at least 80 % in the recertification examination, one further attempt at the whole recertification examination shall be allowed after 7 days and before 6 months. In the event of failure in the one allowable retest, the certificate shall not be revalidated and, to regain certification for that sector and method the candidate shall be required to achieve success in the appropriate main method examination. A candidate who does not meet the requirements of the credit system shall be permitted one attempt at the written recertification examination. BS EN 473-2000 pdf download.