Written Practice

What is NDT Written Practice?

An individual company performing NDT inspections, in-house or as a service, shall have a written practice that provides information on training and certification of NDT personnel. As per SNT-TC-1A, Certification of all NDT Levels is the responsibility of the Employer. The written practice also establishes the responsibilities of NDT personnel. Included in the Written Practice shall be the minimum required education, training hours, examinations and experience for certification of NDT personnel. The written practice should include the course outline that must be covered in the training program. The written practice is prepared based on one of the following documents: ASNT’s Recommended Practice SNT-TC-1A, ASNT’s Standard CP-189, and Aerospace Industries Association’s Standard NAS 410.

We can assist a company develop their Written Practice.

What is SNT-TC-1A?
SNT-TC-1A is the
recommended practice for Qualification and Certification of Nondestructive Testing Personnel. The practice provides guidelines for employers to establish in-house certification programs for the qualification and certification of nondestructive testing personnel.
Companies involved in NDT are recommended that they purchase a copy of SNT-TC-1A, 2020 from American Society of Nondestructive Testing.

What is NAS 410, Rev 3, Mar 2008?
NAS 410 is Aerospace Industries Association’s National Aerospace Standard for Certification and Qualification of Nondestructive Test Personnel. Methods included are UT, ET, PT, MT, RT, IRT and ST. The table above provides training hours for certification towards Level I and Level II. Note that the total training hours required for PT Level II and MT Level II are 32 hours that are significantly higher than that required for SNT-TC-1A. This standard is available from IHS

What is ISO 9712?
ISO 9712 provides the certification requirements as per the ISO standards. The certification is performed by authorized independent certification bodies

What is ACCP?
ACCP is central certification that is administered by ASNT. ACCP meets the requirement of ISO 9712. As per ASNT, “With central certification employers will be able to hire NDT personnel without the need to administer exams before they can begin work, a savings of time and money. It provides a uniform standard for the profession and brings more credibility to the industry. Significantly, it raises the quality bar for nondestructive testing”.

MINIMUM TRAINING HOURS AS PER SNT-TC-1A, NAS410 AND ACCP. Following are the minimum training hours required as per SNT-TC-1A and NAS 410. The table provides training hours for certification towards Level I and Level II. For example, MT Level II certification requires a total of 20 hours (12 for Level I AND 8 for Level II) of training for SNT-TC-1A.

SNT-TC-1A 12 8 4 8 40 40 8 16 40 40
NAS 410 16 16 16 16 40 40 40 40





What is CP-189, 2006?
CP-189 is ASNT’s Standard for Qualification and Certification of Nondestructive Personnel. CP-189 is somewhat similar to SNT-TC-1A but has very specific requirements. CP-189 is available from  ASNT.

What is the difference between SNT-TC-1A, CP-189 and NAS410 ?
SNT-TC-1A is a guideline or recommended practice while CP-189 and NAS 410 are standards.  Another difference is that SNT-TC-1A document uses the word “should” while CP-189 and NAS 410 use “shall”.

What is EN 4179:2005 ?
EN4179 is a standard published by the European Committee for Standardizationis entitled Qualification and approval of personnel for non-destructive testing. As per the foreword of EN 2179:2005. “the document (EN 4179:2005) is technically equivalent with NAS 410”.

Note: Birring NDE Center strongly recommends that in order to obtain accurate information, the readers purchase the original documents from the respective publishers. We are not in any way responsible for the accuracy of the above content.