Page 75 - 2018-2019 ASNT Region 16 Yearbook

REGION 16 of the AMERICAN SOCIETY FOR NONDESTRUCTIVE TESTING
ALASKA, COLUMBIA RIVER, LEWIS & CLARK, PACIFIC NORTHWEST SECTIONS
2018-2019 YEARBOOK

DEFINITION OF NONDESTRUCTIVE TESTING

Nondestructive testing (NDT) has been defined as comprising those test
methods used to examine an object, material or system without impairing its
future usefulness. The term is generally applied to nonmedical investigations of
material integrity.

Strictly speaking, this definition of nondestructive testing does include
noninvasive medical diagnostics. Ultrasound, X-rays and endoscopes are used
for both medical testing and industrial testing. In the 1940s, many members of
the American Society for Nondestructive Testing (then the Society for Industrial
Radiography) were medical X-ray professionals. Medical nondestructive testing,
however, has come to be treated by a body of learning so separate from
industrial nondestructive testing that today most physicians never use the word
nondestructive.

Nondestructive testing is used to investigate the material integrity of the test
object. A number of other technologies - for instance, radio astronomy, voltage
and amperage measurement and rheometry (flow measurement) - are
nondestructive but are not used to evaluate material properties specifically.
Nondestructive testing is concerned in a practical way with the performance of
the test piece - how long may the piece be used and when does it need to be
checked again? Radar and sonar are classified as nondestructive testing when
used to inspect dams, for instance, but not when they are used to chart a river
bottom.

In blunt language, a nondestructive test does not improve quality. It can help to
establish the quality level but only management sets the quality standard. If
management wants to make a nearly perfect product or wants at the other
extreme to make junk, then nondestructive tests will help make what is wanted,
no more and no less. In preparing a drawing for a part, the designer sets
tolerances on dimension and finish. If a drawing specifies a certain dimension
as 32 mm (1.25 in.) but fails to specify the tolerance, the machine shop
supervisor rejects the drawing as incomplete or assumes the standard
tolerance. In nondestructive testing, a quality tolerance (the tolerance on the
characteristic being tested) or criteria for acceptance or rejection must also be
specified.

To Serve or Not to Serve
An article regarding the legal liability of serving alcohol related beverages at
ASNT events.

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