MIL-DTL-23659F
APPENDIX A
A.7.4. Safety Review. Safety approval of all safety-critical initiation systems is required for
each munitions system. During that the review the ILI characteristics will be reviewed in detail.
A.7.5. Maximum No-Fire Stimulus. The firing properties test data can used to determine
several points of general interest in the ILI operating characteristics, including Maximum No-
Fire Stimulus (MNFS). MNFS shall not be confused with Maximum No Fire Voltage (MNFV)
which is an estimate associated with this document. MNFS is defined and is the same in all the
initiation safety standards (MIL-STD-1316, MIL-STD-1901 and MIL-STD-1911) and reflects a
commonly used probability point for an ILI, that is, the maximum stimulus that will not fire an
ILI. For most ILI, voltage is generally the stimulus of interest in determining MNFS. The firing
properties test data can be used to determine the MNFS and is identical to the Fuze Arming
Voltage (FAV).
A.7.6. Test Specific Information. The following additional information is listed
alphabetically. The purpose of the additional information is:
a. Clarification of requirements that are frequently misinterpreted;
b. Explanation of those requirements that are stated in a manner to allow for technological
growth, but do not imply an obvious current solution;
c. Historical information which may be useful in future specification reviews, or updates.
A.7.6.1. All-Fire Performance. Design and manufacturing flaws can exist that would not be
discovered by a small number of test firings. Requiring the certification be performed on a
larger number of ILI limits the possibility that the manufacturing for the certification units will
not be representative of production units. This test is to demonstrate the ILI certification sample
has a reliability of at least 0.99 at 95% confidence after being subjected to common
environmental stimuli. To establish this reliability level a test quantity of 298 ILI must be fired
with no failures in the all-fire performance tests. The ILI should be fired at the firing voltage
intended for its application. These tests do not necessarily depend on the statistical all-fire
voltage projection for device reliability. Some developers may propose to accept ILI designs on
the basis of extrapolated projections of successful statistical properties. It is worth noting that it
is possible to statistically project acceptable all-fire voltages using ILI that are unreliable.
A.7.6.2. Electrical Cook-Off. The intent of this test is to establish the nature of the energetic
reaction when an ILI is inadvertently subjected to a current source from commonly available
power supplies. Reactions, for this test, include lower order reactions such as deflagration, upon
exposure to commonly available power sources.
a. A detonation of the EFI during this test will eliminate the EFI from consideration for
non-interrupted explosive train applications. In their assembled configuration within the fuzing
system, MIL-STD-1316 requires electrically fired initiators used in non-interrupted applications
to be incapable of being initiated by any electrical potential of less than 500 volts applied to any
accessible part of the fuzing system. The term initiate is intended to include not only the design
mode detonation, but also any energetic reaction of the energetic material contained within the
EFI. As a result of this requirement, no energetic material reaction is allowed if the EFI is
intended for use in a stand alone configuration item or if the leads to the EFI or the EFI assembly
can be directly accessed for test or other instrumentation purposes at the munition level, or the
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