Volume 6, Number 2
April 2007
Q. My Level III has advised that SNT-TC-1A 2001 paragraph 8.2.2 specifies a requirement for distinguishing between shades of gray and has recommended a contrast sensitivity chart for this purpose. Can you clarify the interpretation, as the general opinion from those I have spoken to claim the contrast sensitivity chart is relevant to radiography. My employer does not carry out any radiography and I am not sure whether SNT-TC-1A makes a distinction between methods when calling for this test. L.V., Aberdeenshire, UK A. Paragraph 8.2.2 (Color Contrast Differentiation) of the 2001 edition of SNT-TC-1A states “The examination should demonstrate the capability of distinguishing and differentiating contrast among colors or shades of gray used in the method as determined by the employer. This should be conducted upon initial certification and at three year intervals thereafter.” You can see that paragraph 8.2.2 specifies colors or shades of gray. An exam to determine shades of gray that might be appropriate for radiographic film interpretation would not be an appropriate exam for penetrant tests that utilize visible red dye. Your query is one of many interpretation requests made regarding eye exams recommended in SNT-TC-1A, and has been specifically addressed in Inquiry 78-11 of Interpreting SNT-TC-1A. Part two of the response made by the SNT-TC-1A Interpretations Panel explains the intention of paragraph 8.2.2 as follows: “... such practical examinations include checkpoints as appropriate to verify that the candidate’s color vision capabilities are adequate to satisfy the specific needs imposed by the NDT method in question, the employers test equipment, procedures and products.”
Q. A customer visited our facility recently to see a magnetic particle indication. He had a pacemaker and asked if it would be safe for him to be near our equipment. Fortunately, the discontinuity he was there to see could give a clear indication after the part was removed from the machine so we decided not to turn the machine on while he was in the area. Was there a legitimate need for our concern? A. Safety first is always sound policy in the workplace so you were right to exercise caution. Pre-emptive measures are perhaps the best approach to potentially problematic situations and awareness is a key component of these preparations. As a first step, an individual with an implanted pacemaker or defibrillator should always consult beforehand with his or her doctor concerning any proposed activities. TNT
E-mail, fax or phone questions for the Inbox to the Editor:
hhumphries@asnt.org
(800) 222-2768 X 206
(614) 274-6899 fax
[ The NDT Technician ]
Copyright © 2010 by the American Society for Nondestructive Testing, Inc. ASNT is not responsible for the authenticity or accuracy of information herein. Published opinions and statements do not necessarily reflect the opinion of ASNT. Products or services that are advertised or mentioned do not carry the endorsement or recommendation of ASNT.IRRSP, NDT Handbook, The NDT Technician and www.asnt.org are trademarks of the American Society for Nondestructive Testing, Inc. ACCP, ASNT, Level III Study Guide, Materials Evaluation, Nondestructive Testing Handbook, Research in Nondestructive Evaluation and RNDE are registered trademarks of the American Society for Nondestructive Testing, Inc. ASNT exists to create a safer world by promoting the profession and technologies of nondestructive testing.
