Nondestructive Testing and What Certification Fits Your Gear Production Needs

If nondestructive testing is a requirement of your gear production process, be sure to choose what best suits your product and your intent.


Nondestructive testing (NDT) is a fascinating and ever evolving field prevalent within the gear industry. It is because of this evolution that a need for standardization is warranted. This standardization can be achieved through a certification scheme that meets both your company and product’s needs. The two main certification systems, which I will describe in more detail, can be categorized into either an Employer Based System or a Central Certification System.

The first document circulated in an attempt to standardize NDT certification is the recommended practice, ASNT SNT-TC-1a.1 The intent of this document is to provide general guidelines for training, education, and experience requirements in order to qualify or certify an employer’s personnel to perform nondestructive testing. The employer then has to create a procedure or written practice that will incorporate all of the specific details of a company’s NDT system. This document is the framework for their internal NDT functions. Within this written practice, levels of certification distinguishing competencies are established, typically including a trainee and incrementing in levels of certification all the way to a Level III technician. A great advantage of the Employer Based System is that it can be created specifically to cater to a company’s specific needs. It may include specialized techniques, newer processes yet to be established, or allowing limited certifications for specific tasks that may not warrant a full NDT certification. The implementation and supervision of this system is monitored and controlled by an in-house Level III designee. The creation of SNT-TC-1a and the movement of Employer’s written practices was a stepping-stone to a more defined Employer Based System.

After guidelines had been established and employers began defining their own practices using a “recommended” practice, the industry began to evolve. As you can imagine, the definitions of certification levels and the structure of the independent NDT systems began to take on a uniqueness all their own. The Department of Defense adopted a similar document in the late 1990’s, NAS-410, in order to enforce the minimum requirements for certification and qualification of personnel. If a company adopted this document they could still modify their written practice to establish their individual needs, but they could not violate the minimum requirements.

As I mentioned earlier in this article, this in-house control was beneficial to allow a company to adapt to their specific needs. However, this adaptability also presents a problem because the system is based only on 1st Party2 auditing, which introduces overall variability in interpretation and rigor of execution among companies, and potentially bias due to having a vested interest in a successful outcome. Sometimes, customers knowledgeable in NDT can perform 2nd Party3 auditing to reduce variability, but this will differ by each supplier-customer relationship throughout the industry. If your company does not have expertise and/or product experience to provide oversight to your supplier, how are you to verify that these (often critical) tests are being performed by qualified individuals?

Regardless of the system, one of the most critical steps in achieving a level of NDT certification is taking the required examinations. This includes a hands-on practical examination using test props that are similar to daily NDT processing, a 30-question specific examination predicated from common specifications and procedures, and a 40-question general examination based upon general theory, principles, and fundamentals. The practical examination is still largely company-specific and dependent upon the product that individual technician will be testing. The other two examinations are based upon what is to be considered “standard” industry knowledge. Again, the need for standardization is present.

ASNT (American Society for Nondestructive Testing) certification4 is a 3rd party certification that works hand-in-hand with the Employer Based certification system. For a standard Level II certification, both a specific and general examination is administered in the method. These examinations would have a standardized bank of questions controlled, monitored, and graded by ASNT, a 3rd Party5 monitor. The advantage of this certification is that a 3rd party, independent of the employer’s needs, can give a guarantee of a certain level of minimum knowledge and competency that can be recognized throughout the industry. In addition to the examinations, a code of ethics is presented to the technician providing a high moral standard that must be fulfilled. While ASNT takes credit for the examinations administered, it is the sole responsibility of the employer for authorizing their employees to perform Nondestructive testing in the certified method. If a technician leaves his/her place of employment, his/her certification is no longer valid or complete. This presents the need for a Central Certification System.

A Central Certification System allows a technician to be independently certified with no dependency attached to an employer. ASNT’s version of the Central Certification System is the ACCP (ASNT Central Certification Program). This program meets and exceeds all aspects of the ASNT certification program and provides a higher standard of training, skill, and knowledge evaluated by a 3rd Party and made transportable to the NDT technician. The ACCP certification offers individual sectors within a method that a technician can certify to—for example, pressure equipment (PE) or aviation/aerospace (AA) ultrasonic certification. With all ACCP certifications, practical examinations are administered with test props that have 3rd party engineered flaws in conjunction with confidential answer keys. Certifications are made public on the ASNT website, which allows customers to verify their supplier’s credentials, and potential employers of a certified technician to have some verifiable understanding of a technicians credentials.

There are a number of organizations and committees that have published recommended or mandatory NDT certification and qualification documents. I have outlined a few of the main American schemes. My employer, Scot Forge Company, carries and promotes all of the certification schemes I have described to provide the best opportunities and highest level of competency in our technicians and the examinations they provide. If nondestructive testing is a requirement of your product, be sure to choose what best suits your product and your intent.

1. Personnel Qualification and Certification in Nondestructive Testing
2. 1st Party: an activity, such as auditing or testing, that an organization performs on itself
3. 2nd Party: an activity, such as auditing or testing, that an organization performs on a supplier
5. 3rd Party: an activity, such as auditing or testing, that is conducted by an independent organization upon another organization