||MIL-STD-2036: General Requirements for Electronic Equipment Specifications
5.1.2 Environmental Conditions
Sections 126.96.36.199 -
188.8.131.52 Nuclear hardening. Requirements for nuclear
hardening shall be as specified herein.
184.108.40.206.1 Fully hardened.
Levels of nuclear survivability shall be tailored from NAVSEA Instruction
C3401.1. Requirements for air blast, thermal radiation, and free field EMP
shall be tailored from NSWC TR 87-192 for exposed equipment and cables;
modified to limit conducted current levels to 10A on cables that penetrate the
ship's hull. Requirements for air blast induced shock, transient radiation
effects on electronics (TREE), and conducted EMP shall be tailored from NSWC
TR 87-192 for all equipment. EMP tests shall be tailored in accordance with
the RS05 and CS10 requirements of MIL-STD-461 (see 220.127.116.11).
18.104.22.168.2 Minimal acceptance. It is the responsibility of the
specifier to determine if the equipment requires nuclear hardening, and the
degree of nuclear hardening. DOD Directive 4245.4 provides further guidance.
Installation in a sheltered, controlled environment does not protect the
equipment from all effects of a nuclear event.
techniques. With proper care, COTS equipment can be ruggedized to meet the
nuclear environment. The specifier may consult NSWC TR 90-22 for techniques to
harden equipment to the nuclear environment. Suggested guidelines for
hardening are provided below.
(a). Air blast and thermal radiation:
Appropriate shielding and insulation may be applied to protect exposed
(b). Air blast induced shock: To meet this requirement and
the underwater shock requirements of MIL-S-901, equipment may be shock mounted
(c). EMP: Appropriate electromagnetic shielding and
grounding shall be used. Protection may be applied at I/O ports to prevent
propagation of the EMP pulse into equipment. For small signal interfaces,
terminal protection devices (TPDs) or filter pin connectors shall be used due
to the fast rise time of the EMP pulse. For power circuit interfaces, metal
oxide varistors (MOVs) may be applied.
(d). TREE: The ship's hull is
relatively transparent to the TREE conditions. Radiation detection, power
interruption and dump may be applied. With this approach, a radiation
detection integrated circuit (IC) provides a signal for power supplies to
momentarily turn off, and high voltage circuits and capacitors to be
crow-barred (discharged to ground). A radiation detection IC is under
development and will also be available as a SEM module of the Standard
Hardware Acquisition & Reliability Program (SHARP) program at NWSCC,
Crane, Indiana. Using this approach, any momentary component latch-ups will
not result in a sustained fault of components and subsequent failure. Power
supplies of COTS equipment and capacitors used to store energy would be
modified to interface with the radiation detection IC. Other methods employed
include component selection and component derating. Fiber optics may be
sensitive to TREE conditions. Fiber optic cables shall be selected which are
insensitive to TREE.
22.214.171.124 Salt fog (spray). Requirements for salt fog (spray) shall be as
126.96.36.199.1 Fully hardened. Equipment shall be tested
in accordance with MIL- STD-810, method 509. As an alternative, equipment may
be tested in accordance with IEC 68-2-11Ka, except with a duration for
exposure of 48 hours.
acceptance. Generally, requirements for salt fog effects are not applicable.
Requirements for equipment operation under salt fog effects shall be specified
only for those installations determined by the specifier to be subjected to
salt fog effects.
188.8.131.52 Ship motion and attitude. Requirements for
ship motion and attitude shall be as specified herein.
Fully hardened. Equipment shall be fully operational through the ship motion
and attitude conditions in accordance with DOD-STD-1399, section 301.
Inclination tests shall be as specified in Appendix D.
Minimal acceptance. Ships motion and attitude conditions are defined in
DOD-STD-1399, section 301. Under heavy weather conditions, office equipment
such as duplicating machines may be permitted to shut down when the
inclination exceeds a pre-specified limit.
184.108.40.206 Shock. Equipment
used aboard ship is subjected to shock and vibration as a result of shipping
and service conditions, as well as from hostile engagements (see 220.127.116.11.3
). In all cases, equipment shall be
designed to operate within the service environment to be encountered aboard
ship. Shock tests and requirements for shipboard equipment are specified in
the following documents:
(a). Functional shock: MIL-STD-810, method 516, procedures I and
(b). Storage and transportation: MIL-STD-810, method 516, procedures II,
III, IV, and VIII.
(c). Combat condition: MIL-S-901.
Requirements for shock testing shall be as specified
18.104.22.168.1 Shock spectrum and transient duration. In order to
perform shock tests, a shock spectrum and transient duration shall be defined
which represent the extreme design conditions to be encountered. Where
published data is not available, guidance shall be sought from COMNAVSEASYSCOM
(Codes SEA-06K21 and SEA 55X12).
22.214.171.124.2 Shock Grades. Equipment is
classified into grades in accordance with DOD-STD-1399, section 072.4, in
order to determine the testing requirements for combat shock (see MIL-S-901).
The shock grade, shock spectrum, and transient duration determine the
tailoring requirements for testing.
126.96.36.199.3 Fully hardened.
Equipment shall be classified as grade A and shall be in accordance with
MIL-S-901 in addition to the applicable portions of MIL-STD-810, method 516.
188.8.131.52.4 Minimal acceptance. Equipment which is normally stowed for
combat shall be classified as grade C with no testing requirements. All other
equipment shall be classified as grade B and be tested in accordance with MIL-S-901. Note: MIL-S-901 does specify