MIL-PRF-24775A(SH)
4.5.2.15 Group B test schedule. The schedule for Group B tests shall be performed in the following order:
a.
The following tests shall be conducted concurrently: capacities (see 4.5.2.1), condensation (see
b.
Motor tests (see 4.5.2.5).
c.
Airborne noise (see 4.5.2.13).
d.
Permeability tests (see 4.5.2.14).
4.5.3 Group C tests.
4.5.3.1 Shock. Fan-coil units shall be grade A shock tested in accordance with MIL-S-901 for grade A, type A
equipment (see 6.2). Both horizontal and vertical units shall be tested in the shipboard orientation. Testing shall be
conducted on the largest fan-coil unit of each configuration and extended to smaller units in accordance with
MIL-S-901. Tests under group I shock blows shall be conducted with the chilled water cooling coil unit pressurized
to maximum allowable design pressure, the fan operating at high speed, and the heater energized. Tests under group
II shock blows shall be conducted with the unit de-energized and depressurized. The shock test shall be conducted
prior to any other tests and further testing shall not be performed until the fan-coil unit passes the shock test. Fan-
coil units not required to meet HI shock shall be tested to meet the requirements for grade B shock as defined in
MIL-S-901.
4.5.3.1.1 Criteria of acceptance. Compliance with the following requirements shall constitute successful
completion of the shock test:
a.
No portion of the equipment shall come adrift or otherwise create a hazard to personnel. (Grade
A and B)
b.
There shall be no evidence of leakage of the chilled water cooling coil or operational malfunction of
the fan, motor, or heater. (Grade A only)
c.
The fan-coil unit shall pass a post shock test, functional test, and inspection in accordance with
MIL-S-901. Post shock tests shall be completed prior to correcting any damage, which may have
occurred during the shock test. (Grade A only)
d.
After shock testing, the cooling coil of the fan-coil unit shall successfully pass a hydrostatic or
pneumatic leakage test as specified in 4.5.3.2. (Grade A only)
4.5.3.2 Cooling coil leakage. The cooling coil of each fan-coil unit shall be tested in conformance with the
standard hydrostatic test of ASME Boiler and Pressure Vessel Code (BPVC) at a minimum hydrostatic pressure of
300-lb/in2 gauge (1.5 times the maximum allowable working pressure). This test shall be performed using clean
fresh water. Where water would have a detrimental effect or present production problems, a pneumatic test in
accordance with ASME BPVC using a minimum pneumatic pressure of 250-lb/in2 gauge (1.25 times the maximum
allowable working pressure) shall be performed. Any fan-coil unit in which there is evidence of cooling coil
leakage when tested shall not be offered for delivery.
4.5.3.3 Internally excited (self-excited) vibration. Fan-coil units shall pass type II vibration tests in accordance
with MIL-STD-167-1 for first and second order frequencies. The capability of the rotating components to meet the
balance requirements of 3.13.2 shall be demonstrated in accordance with MIL-STD-167-1 for type II vibration for
first and second order frequencies.
4.5.3.4 Environmental (externally excited) vibration. Fan-coil units shall be subjected to type I environmental
vibration tests in accordance with MIL-STD-167-1 (see 4.2). The exploratory vibration test specified in
MIL-STD-167-1 shall include frequencies up to and including 33 Hz at the table amplitude specified therein. Both
horizontal and vertical units shall be tested in the shipboard orientation. This vibration test shall be conducted
following shock testing of 4.5.3.1 including the cooling coil leakage test and before any other tests. Testing shall be
conducted on the largest fan-coil unit of each configuration and extended to smaller units. The fan-coil unit shall
not be damaged or malfunction be caused as a result of environmental vibration tests.
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