MIL-DTL-5523E
4.4.2.3.2 Burst pressure type I system valves. W ith all ports except the pressure port plugged, pressure shall be
applied at a rate not exceeding 25,000 psi per minute as specified for burst pressure in table II. This pressure shall
be held for at least 2 minutes. When subjected to the rated burst pressure specified in table II the valve shall meet
the requirements of 3.5.2.
TABLE II. Operational requirements at normal and high temperatures.
Rated flow press.
Min reseat press.
Emergency setting
Proof
Burst
setting (psi)
(percent of rated
press. (percent of
press
press
rated flow press.)
flow pressure)
(psi)
(psi)
Class
(Min)
(Max)
(Min)
(Max)
YZ
100
1000
82
85
100
1500
2500
AB
1000
2300
82
85
100
3000
5000
CD
2300
3850
82
85
100
4500
7500
4.4.2.4 Normal temperature performance. Valves when subjected to the normal temperature performance test shall
meet the requirements of 3.5.3. The following details shall apply:
4.4.2.4.1 Minimum setting. A typical setup for this test is specified on figure 2. The power-driven pump shall be
used for the following tests. With a pressure at the outlet port of 200 ± 25 psi, for class AB and CD valves only, the
test valve shall be adjusted to deliver rated flow, as specified on the applicable drawing, at a differential pressure
equivalent to the minimum pressure setting specified for its class in table II. Inlet pressure shall be decreased
gradually until leakage corresponding to a maximum value leakage as shown in table III can be determined. This
pressure will be considered as the reseat pressure, and its value shall meet that specified in table II. The reduction of
pressure shall be continued slowly, and leakage shall be observed at pressure valves equivalent to approximately
0.75, 0.50, and 0.25 of the rated flow pressure setting of the valve. Leakage shall not exceed .5 cc (approximately 10
drops) per minute. The pressure shall then be increased gradually, and leakage shall be observed at pressure
values equivalent to approximately 0.25, 0.50, and 0.75 of the rated flow pressure setting of the valve. The pressure
shall then be increased slowly until a leakage equivalent to 3 times the value specified in table III is noted. The
pressure at this value shall not be less than 91 percent of the rated flow pressure. Leakage shall be equivalent to
that observed during the reduction of pressure portion of this test. Rated flow shall occur at the original pressure
setting. In all instances leakage shall be observed at the outlet port and it shall be taken during the third minute
following a 2-minute waiting period.
TABLE III. Allowable leakage.
Tube Size
Max Leakage cc/min
-4
0.5
-6
0.5
-8
2
-12
3
4.4.2.4.2 Maximum setting. The tests outlined under paragraph titled "Minimum setting" shall be repeated with the
valve adjusted to deliver rated flow at a differential pressure equivalent to the maximum pressure setting specified for
its class in table II.
4.4.2.4.3 Leakage and emergency setting pressure. With the pressure setting unaltered after completion of
maximum setting tests and by use of the hand pump specified on figure 2, leakage readings shall be taken at
pressure values equivalent to approximately 0.25, 0.50, and 0.75 of the rated flow pressure setting of the valve under
conditions of increasing as well as decreasing pressure. Leakage during the third minute after a 2-minute waiting
period shall not exceed 0.5 cc (approximately 10 drops) per minute. Pressure shall then be increased until leakage
exceeds the value specified in table III. This value shall be considered as the emergency setting pressure and shall
be within the limits specified in table II.
4.4.2.4.4 Endurance. A typical setup for life cycling is specified on figure 1. The endurance test shall be performed
on the maximum clearance specimen and shall consist of adjusting the valve to the maximum pressure setting at
rated flow at normal temperature as specified in table II, and the cycling at the rate of 5 to 35 cpm for 50,000 cycles.
Each cycle shall consist of imposing rated flow through the valve, and reducing pressure to substantially zero. After
completion of this test, internal leakage at the reseat pressure and 0.25, 0.50, and 0.75 of the rated flow pressure
setting, shall be a maximum of two times the values permitted in 4.4.2.4.2.
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