Written Practice and the Process for Certification of NDT Personnel

A Written Practice is a procedure that provides minimum requirements for “Certification of NDT Personnel”. This includes education, training hours, examinations and experience for certification of NDT personnel. The written practice is prepared based on one of the following documents: ASNT’s Recommended Practice SNT-TC-1A, ASNT’s Standard CP-189, or Aerospace Industries Association’s Standard NAS 410. Any company certifying their NDT inspectors must have a Written Practice.
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 to purchase the latest copy of SNT-TC-1A from the American Society of Nondestructive Testing. Current version is SNT-TC-1A 2024

What is NAS 410?
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, and RT. The table below 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 (32 hours) are significantly higher than that required by SNT-TC-1A.

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 ASNT 9712?
ASNT-9712 is central certification that is administered by ASNT. ASNT-9712 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 and Experience Hours
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.

What is CP-189?
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, ISO 9712, CP-189 and NAS410 ?
SNT-TC-1A is a guideline or recommended practice while ISO 9712, CP-189 and NAS 410 are standards.  Another difference is that SNT-TC-1A document often uses the word “should” while the standards use “shall”.

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.