The American Society for Nondestructive Testing (ASNT) Recommended Practice No. SNT-TC-1A had its beginning in the early 1960's. The Society for Nondestructive Testing (SNT at that time) Board of Directors charged the Technical Council to develop a set of guidelines which could be used by employers to develop their own "In -house" employer based training, qualification and certification programs.
This set of guidelines, first published in 1966, is called the Recommended Practice No. SNT-TC-1A. This document established levels of qualification based upon a combination of education, training, experience, and qualification examinations.The basic levels begin with NDT Level I primarily used as an operator technician. NDT Level II, the next level requires more training and experience, but permits more independent activity including accepting and rejecting products, materials and/or components. The NDT Level III usually requires four (4) years of experience as an NDT Level II in the method. However, the number of years of experience depends upon the candidate's formal education.
While there are several personnel qualification and certification programs used, SNT-TC-1A employer based certification has been widely accepted throughout the United States as the primary guide used for NDT personnel certification. This document is revised periodically, usually every five (5) years. The current revision is the 2011 Edition.