Standard Test Method for
Measurement of Thickness of Nonmagnetic Materials by
Means of a Digital Magnetic Intensity Instrument1
This standard is issued under the fixed designation D 4166; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope *
1.1 This test method covers the measurement of thickness of
any nonmagnetic material by means of a digital magnetic
intensity instrument.
1.2 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
1.3 There is no similar or equivalent ISO standard.
2. Summary of Test Method
2.1 In this test method, a magnetic sensing device is
calibrated and placed on one side of the material to be
measured. A magnet of known intensity is placed on the
opposite side and the distance between the magnet and the
magnetic sensing device shows as a digit that can be converted
to inch-pound or metric units by reference to a table.
3. Significance and Use
3.1 This test method is useful for measuring the wall
thickness of plastic vessels and other plastic structures where
the geometry of the equipment does not permit direct measurement by conventional methods, such as micrometers, calipers,
and rulers. This test method is not limited to plastics and can be
used for all nonmagnetic materials. It provides for a rapid and
accurate thickness measurement, without the need for drilling
and repair of holes.
3.2 Accuracies are not affected by density variations, permitting the measurement of composites made up of a variety of
materials of varying densities. By placement of the magnetic
source on the mold surface, thickness measurements can be
made during and after fabrication of plastic products to verify
thickness and adherence to specifications.
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