MIL-DTL-23659F
APPENDIX A
A.4.16. All-Fire Performance. The ILI shall fire and produce the required output when
initiated at the minimum firing voltage intended for use with the ILI while temperature
conditioned to ambient at +23 ± 10 C (+73 ± 18°F), hot to a minimum of +71 C (+160°F), and
cold to a maximum of -54 C (-65°F).
A.4.17. High Firing Voltage. Determination of the ILI functional performance shall be made
when initiated by a firing potential at voltage potentials 50 percent above the intended all-fire
voltage or at the maximum limits of the intended-use fireset, which ever is less.
A.4.18. Post Test Pressure Seal. This test shall be performed on ILI that initiate rocket
motors or in other pressure vessel applications where a seal from venting must be maintained
after the ILI is functioned. This test is performed on the ILI hardware following or during All-
Fire Performance Testing. ILI must demonstrate a degree of sealing as specified by the system
requirement or manufacturers specifications that will prevent a loss of pressure. Testing will be
performed as specified in A.6.15.
A.5. EQUIPMENT
Suitable precision instrumentation shall be used, e.g., volt meter, ohm meter, temperature
recorder, accelerometer, transient recorder, storage oscilloscope, transducers, current viewing
resistor (CVR), strain gages, etc. Documented calibration records, as whole or individual
components shall be maintained for reference. Digital recorders, storage oscilloscopes, etc.,
shall be capable of reciprocal sample rates that are a maximum of one fifth the time resolution
required to acquire data. Unless otherwise specified all electronic voltages, currents, and
resistance shall be accurate to a tolerance of 1 percent or less.
A.5.1. Firing Properties Firing Unit. The firing unit for the firing properties tests and the all-
fire tests shall be as close as possible to the intended-use firing unit configuration, preferably
using the same components. Firing switches that will not operate in the same voltage range as
the intended firing switch shall not be substituted. The test firing unit shall have transient firing
properties that are within 25 percent to that of the intended-use firing properties after
modifications are made to measure the necessary data (such as the addition of a current viewing
resistor). Transient firing properties are a measure of discharge impedance and should include
measurements of dynamic (steady state) resistance, inductance, and capacitance as determined
through short circuit fireset discharge (ringdown) analysis at the appropriate voltages at the
threshold and all-fire voltages. Ringdown analysis of both the test and intended-use firing units
shall be documented. The MASS and MNFV safety requirements shall be met after scaling the
appropriate voltages by the ratio of peak currents on the intended-use firing unit divided by the
ratio of peak currents on the test firing unit. This scaling factor is the ratio of the relative
impedances of each fireset. The proper use of the scaling factor can be illustrated using Figure
A-2, where:
I1iu and I2iu are the first and second positive peak currents respectively from a ringdown at a
specific voltage of the intended-use fireset and
I1t and I2t are the first and second positive peak currents respectively from a ringdown of the
test fireset at the same voltage; then
the scaling factor used to calculate the actual values for the intended-use fireset is equal to
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