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|  MIL-F- 14252( AR )
4. 3.4 Humidity
4. 3.4.1 Procedure I.- Distilled or demi erallzed water having
ph value between 6.5 and 7.5 at 25c (77 F) shall be used to
obtain the desired humidity. The equipment, prepared for normal
-
operation, shall be placed In the test chamber so that It is
no closer than 6 inches from the sides of the chamber, and Is not
being subjected to radiant heat. The humidity of the chamber
shall be adjusted to 95
5 percent and maintained at that value
during the remainder of hj test unless otherwise specified. The
temperature of the chamber is raised at a linear rate for a per-
iod of 30 minutes until a temperature of 46 + 1C (115 / 2F)
is reached and maintained at that temperature for a period of
4-1/2 hours . The temperature of the test chamber is reduced at
a linear rate for a period of 1.0 hour until a temperature of
27 + l"c (8o
change
shall
be
optional,
consistent
with maintenance of the maximum temperature not in excess of 20
minutes out of each how. At least once each hour the relative
humidity shall be 100 percent with condensation, the duration of
which shall be optional and reed not necessarily coincide with
the maximum temperature phase of the hourly cycle. The above
noted 12 hour cycle shall be repeated 20 times. During the low
temperature period of the tenth and twentieth cycles, the equip-
ment shall be tested as specified In the detail specification.
At the conclusion of the test, the equipment is returned to
normal ambient temperature and tested as specified in the detail
specification.
4.3.4.2 procedure II.- The equipment shall be placed in a test
chamber and t he 0temperature in 0the chamber raised from a tempera-
0
0
0
0
ture between 20 c and 38 c (68 F to 100 F) to 71 C (160 F) and
at 99 percent relative humidity during a 2 hour period. The
C
temperature of 71 C (160F) and a relative humidity of 95 percent
shall be maintained during the next 6 hour period. During the
following 16-hour period, the0 temperature in the chamber must
0
0
o
drop at a uniform rate to 20 C to 38 c (68 F to 100 F) which con-
stitutes one cycle. The cycle shall be repeated a sufficient
number of times to extend the total time of the test to 360 hours
(15 cycles) or as specified by the detail specification. At the
conclusion of the 360 hour period, the equipment shall be operated
and the data compared to that obtained in 4.2.2 and a visual
examination made in accordance with 4.2.3. Distilled or demin-
eralized water having a pH value of between 6.5 and 7.5 at 25C
(77 F) shall be used to obtain the desired humidity
0
.-.
4.3.4.3 Procedure III.- The equipment shall be placed in a
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