MIL-DTL-16377J(SH)
4.8.17.4 Thermal shock test. Sample glassware shall be uniformly heated to a temperature of 212±3.6 °F
(100±2 °C) for 1 hour. The samples shall then be immediately immersed completely in water at a temperature of
32 to 50 °F (0 to 10 °C). At least ten consecutive cycles shall be performed on each sample (see 3.7.7.7).
4.8.17.5 External hydrostatic pressure test. Sample glassware shall be installed on lights for which they are
designed and shall then be submerged in water in a pressure tank. An external hydrostatic pressure as specified in
the applicable specification sheet shall be applied for a period of 1 hour (see 3.7.7.8).
4.8.17.6 Breakage pattern test. Sample glassware shall rest with its flat surface on a soft 2-foot by 2-foot by
2-inch thick wood plank as shown on figure 18. A steel ball shall be allowed to fall free and strike the glassware on
the center of the outside surface with a force great enough to break the glassware (see 3.7.7.9).
4.8.18 Magnetic permeability. The magnetic permeability of the material shall be determined in accordance
with ASTM A342/A342M (see 3.4.8).
4.8.19 Ambient temperature. The lights shall be operated for 100 hours at the ambient temperature and voltage
specified in the applicable specification sheet (see 3.5.17). The light shall be fully assembled (with all gaskets, if
applicable, in place).
4.8.20 Lumen maintenance test for type III luminaires. Testing and verification shall be accomplished using
the following procedures.
4.8.20.1 Lumen maintenance, ambient (1,000 hours at 77 °F [25 °C]) test. Lumen maintenance testing shall be
accomplished using the following procedure and data from the LED manufacturer.
a.
The luminaire shall be mounted in its proposed orientation.
b.
Ambient testing shall be conducted for a minimum 1,000 hours.
c. The ambient temperature shall be stabilized at 77 °F (25 °C) and maintained within ±3.6 °F (±2 °C)
throughout the test.
d. Stabilization is achieved when the variation of at least three readings of ambient temperature and electrical
input power, recorded over a 30-minute period and taken 15 minutes apart, are less than 1 percent. Stabilization
time shall be recorded.
e. Select one centralized LED within the luminaire, conduct the following measurements after stabilization
and at t=0:
(1) Voltage drop (V) across the LED.
(2) Current (I) in series with the LED.
(3) Case temperature (TS) directly on the LED.
f. TS shall be recorded at t=0 and sequential 1 hour intervals throughout the testing period. TS versus time
shall be plotted for the 1,000-hour test period. The location of the TS probe shall be documented by photos and
diagrams.
g. The ambient temperature (Ta) shall be measured and recorded at t=0 and sequential 1 hour intervals
throughout the testing period. Ta versus time shall be plotted for the 1,000-hour test period. The location of the Ta
probe shall be documented by photos and diagrams.
4.8.20.2 Lumen maintenance, accelerated (1,000 hours at 122 °F [50 °C]) test. Testing shall be conducted as
specified in 4.8.20.1 with the ambient temperature increased to 122 °F (50 °C). The lumen output shall be measured
before and after the test to demonstrate the luminaire has proper thermal management to survive in high-temperature
locations. This test is not intended to adjust the lifetime predictions of 3.7.11.1.
4.8.20.3 Lumen maintenance photometric test. Luminous flux shall be measured using methods described in
IES LM-79 before starting the lumen maintenance test, t=0, and at the conclusion of the lumen maintenance test,
t=1,000 hours.
4.8.21 Power interface test. The fixture shall be subjected to power interface testing per MIL-STD-1399-300
(see 3.6.18).
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