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."
On Apr 22, 8:07 pm, Raghuram Bathula <raghurambath...@gmail.com>
wrote:
> Dear Mr Raghavendra
>
> I was just going thro the pages (In box) of TNT journal published by
> ASNT, the below is the extract
>
> 've noticed a few inquiries lately about Section 8.2.2 of SNT-TC-1A
> 2001 in the "Inbox". Having run into this particular issue myself a
> couple of years ago during an audit, I have this to offer. Section
> 8.2.2 states in part "... distinguishing and differentiating contrast
> among colors or shades of gray used in the method... ." In MT and PT
> inspections, this usually means color vision capable of determining
> red powder and/or red dye. In radiography this would be shades of
> gray. The Ishihara color vision test is one of the accepted and
> standard tests used to meet the needs and requirements for color
> vision tests. A test standard does exist for gray scale — the Pelli-
> Robinson test. Called my ophthalmologist and he referred me to a
> supplier. S.C., Bakersfield, CA
>
> However i could not find any links in the Bakersfield site
>
> for more information you may writre to him or call him {(The Editor of
> The NDT Technician (a.k.a TNT)}
> hhumphr...@asnt.org
> (800) 222-2768 X 206
> (614) 274-6899 fax
>
> On Apr 22, 4:49 pm, "RAGHAVENDRA PEMMARAJU" <r...@hzw.ltindia.com>
> wrote:
>
> > Can any one of you suggest who is the supplier of Pelli-Robinson test kit which is useful for gray scale test as per above requirement.
>
> > regards,
> > Raghavendra
>
> > Larsen & Toubro Ltd.www.larsentoubro.com
>
> > This Email may contain confidential or privileged information for the intended recipient (s) If you are not the intended recipient, please do not use or disseminate the information, notify the sender and delete it from your system.
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