MIL-PRF-44423A
f. The control set points shall be as follows:
Dark cycle
Light cycle
Black panel
38�C
77�C
Conditioning water
40�C
53�C
Wet bulb depression 1/
0�C
10�C
1/ As a guide only; adjust to achieve required relative humidity (see e. above).
g. The test specimens shall fit smoothly on the specimen rack of the apparatus with no
wrinkles or gaps. The test specimen shall be mounted to the outside of the rack with the use
of appropriate stainless steel spring clips. After the required exposure period, the specimens
shall be removed from the apparatus and allowed to dry and condition at Standard Conditions.
Then test specimens for each required test shall be cut and tested appropriately.
NOTE: Monitoring of dry bulb temperature, wet bulb depression, irradiance, and black panel
temperature is recommended through the use of chart recorders.
4.4.5 Flame resistance. Method 5903 of FED-STD-191 except that five specimens shall be
tested in the warp direction only. In addition to after flame time and char length, any
evidence of flaming, melted or molten pieces dropping from the specimen at any time during
the test shall be reported.
4.4.6 Stiffness.
4.4.6.1 TAPPI Method T-451, Preferred Procedure (1), except that five test specimens with
the long dimension parallel to the warp direction of the finished cloth shall be tested and the
standard textile test conditions as specified in ASTM D-1776 shall be used.
4.4.6.2 The stiffness test shall be conducted as specified in 4.4.6.1 except that the apparatus
and test specimens shall be subjected to a temperature of -20�F + 2�F for a period of 2 hours
and the test shall be performed in a still atmosphere at that temperature.
4.4.7 Blocking. ASTM D-751, Determination of Blocking Resistance of Fabrics Coated with
Rubber or Plastics at Elevated Temperatures, except that the test specimens shall be exposed
at an oven temperature of 180�F +2�F for 30 minutes.
4.4.8 Abrasion resistance . ASTM-D-3886 except that three specimens shall be tested on the
face side and three specimens shall be tested on the back side. The abradant shall be the
respective face side or back side of the cloth. Each specimen shall be abraded for 1,000
multidirectional cycles. After abrading, the specimens shall be evaluated for color change in
accordance with AATCC Method 119, using the Gray Scale for Color Change. The class
rating shall be averaged and then rounded to the nearest 0.5.
4.4.9 Color matching. The color of both sides of the cloth shall match the standard sample
when viewed under filtered tungsten lamps that approximate artificial daylight and that have a
correlated color temperature of 7500 + 200oK, with illumination of 100 + 20 foot candles,
and shall be a good match to the standard sample under incandescent lamplight at 2300 +
200oK.
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