MIL-PRF-24755B(SH)
TABLE III. Total sound power levels in decibels (dB) referenced to 10-12 watt.
Octave Band Center Frequency in Hertz (Hz)
Fan Size
Code
63
125
250
500
1000
2000
4000
8000
101
90
95
96
100
107
106
99
90
102
86
92
91
100
100
100
97
88
103
87
97
91
98
99
100
96
85
104
90
92
96
102
104
102
100
93
105
95
97
96
102
103
102
101
94
ANSI/AMCA
6
3
2
1.5
1.5
1.5
1.5
3
300, Standard
Deviation
NOTES:
1.
Measurements of total sound power levels made in accordance with ANSI/AMCA 300 result in measurement
uncertainties within the standard deviations specified in table III. Acceptable fan total sound power levels for
each octave band are those values which are less than or equal to the sum of the tabulated total sound power
level plus the specified standard deviation.
The sound power levels listed in table III do not specify the sound pressure levels generated by the fan in its
2.
installed configuration. The ship designer may need to incorporate noise control/abatement measures to meet
any applicable sound pressure level requirements.
4. VERIFICATION
4.1 Classifications of inspections. The inspection requirements specified herein are classified as follows:
a.
First article inspection (see 4.2).
b.
Conformance inspection (see 4.3).
Periodic conformance inspection (see 4.4).
c.
4.2 First article inspection. First article inspection shall consist of the examinations of 4.6 and tests as specified
in table IV. The tests specified shall be performed on the first production unit of each size fan-motor.
4.3 Conformance inspection. Conformance inspection shall consist of the examinations of 4.6 and tests as
specified in table IV. The tests specified shall be performed on each size fan-motor unit. Any unit that fails to meet
any specified requirements shall be rejected.
4.4 Periodic conformance inspection. Periodic tests are required to assure continuing satisfactory operation of
identical units. The tests are required under any contract or purchase order for fans of existing design when the
invitation to bid is dated four years or more subsequent to the date of the last previous test of an identical unit.
Periodic tests shall consist of the tests specified in table IV and shall be conducted on one of each size fan-motor
unit.
4.5 Composite material. A representative fan constructed of composite material shall meet requirements of 4.8.
9
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business