(a)Test procedures. (1) Prepare two samples for testing that
measure 5 inches by 1/2 inch, by the thickness of the material as it will be
used. Prior to testing, condition the samples at 73.4 ± 3.6°F (23 ± 2°C) and
50 ± 5% relative humidity for at least 40 hours.
(2) Place a sample on supports which are 4 inches apart
and immersed in a heat transfer medium at a test temperature range of 65
°F-80°F (18.3°C - 26.7°C). The heat transfer medium must be a liquid which
will not chemically affect the sample. The testing apparatus must be
constructed so that expansion of any components during heating of the medium
does not result in deflection of the sample.
(3) Place a temperature measuring device with an accuracy
of 1% into the heat transfer medium within 1/8 inch of, but not touching, the
(4) Apply a total load, in pounds, numerically equivalent
to 11 times the thickness of the sample, in inches, to the sample midway
between the supports using a 1/8 inch radius, rounded contact. The total load
includes that weight used to apply the load and any force exerted by the
deflection measurement device.
(5) Use a deflection measuring device with an accuracy of
±.001 inches to measure the deflection of the sample at the point of loading
as the temperature of the medium is increased at a uniform rate of 3.6 ±
.36°F/min. (2 ± 0.2°C/min.). Apply the load to the sample for 5 minutes prior
to heating, to allow compensation for creep in the sample due to the
(6) Record the deflection of the sample due to heating at
(7) Repeat steps 2 through 6 for the other sample.
(b)Acceptable performance. Neither sample shall have a deflection
greater than .010 inch at 180°F (82°C).
[53 FR 23500, June 22, 1988; 53 FR 25569, July 7, 1988; 60 FR 33719, June 29,