||MIL-STD-2036: General Requirements for Electronic Equipment Specifications
5.1.6 Mechanical Design and Construction
Sections 220.127.116.11 -
18.104.22.168 Pockets, wells, and traps. Pockets, wells, and
traps in which water or condensate could collect when the equipment is in
normal position shall be avoided.
22.214.171.124.1 Moisture pockets. Where
moisture pockets are unavoidable in unsealed equipment, provisions shall be
made for drainage of such pockets. Desiccants or moisture-absorbent materials
shall not be used within moisture pockets. Wave guides shall include a method
to purge moisture from low points in the wave guide.
bolts. Calculations for the proper size of deck and bulkhead attachment bolts
shall be based on the minimum elastic-proof load for grade 2 carbon and alloy
steel in accordance with MIL-S-1222.
126.96.36.199.1 Through bolting. Through bolting or through
threading into watertight enclosures shall not be permitted. Bosses shall be
provided in cast enclosures to preclude through bolting or threading. Blind
tapped continuous welded buttons shall be used in sheet metal enclosures.
188.8.131.52 Mounting of electric receptacles. Where practical, when
receptacles are mounted on a vertical surface the largest polarizing or prime
key or keyway of the receptacle shall be at the top center of the shell of the
184.108.40.206.1 Adjacent locations. The use of identical
connectors in adjacent locations shall be avoided. When the use of connectors
of the same size in the adjacent locations cannot be avoided, differences in
the keying arrangement shall be used to prevent mismating.
Location. External connections (excluding test connections) shall not be
located on the front of the equipment.
connections. The method of external connections to equipment enclosures shall
be made by the use of connectors and shall conform to applicable requirements.
EMP protected equipment shall be provided with back shells that can accept
MIL-C-24758 conduit end fittings to provide 360 degrees grounding of the cable
shield. Terminal boards or stuffing tubes shall be used when specified in the
end item specification and the applicable requirements. Terminal boards are
not preferred since they may loosen under vibration conditions. External
connections, excluding test connections, shall not be located on the front of
220.127.116.11.2.2 Terminal board accessibility. Access to
terminal boards and test points shall not be dependent upon removal of cable
entrance plates and cables.
18.104.22.168.1 Watertight joints. Gaskets for watertight
joints shall not be displaced when the door or cover is removed. The design
shall prevent lateral flow of the gasket when under compression.
22.214.171.124 Size and weight. The size and weight of the equipment shall
be constrained as specified in the end item specification and as specified
126.96.36.199.1 Weight. Equipment weight shall be within the limits
specified in the end item specification. The weight of equipment exceeding 15
kilograms (kg) (35 pounds (lbs)) shall be clearly identified on the external
surface of the equipment and readily visible during installation and removal.
Design of rack-mounted and console equipment shall maintain the center of
gravity as low as practical.
188.8.131.52.2 Size limitations. Equipment
size limitations shall be as specified herein. Size limits may be achieved by
use of separable units. Guidance for shipboard mass/size/shape shall be in
accordance with DOD-STD-1399, section 071.
184.108.40.206.3 Maximum height.
Equipment intended for installation within internal shipboard spaces shall be
not greater than 183 cm (72 inches) overall height, including stacked units
and resilient mounts when their use is permitted.
220.127.116.11.4 Surface ship installation. Equipment intended
for installation within internal surface ship spaces shall be constructed to
pass through a doorway 66 cm wide by 167 cm high (reduced further by round
corners on a 20 cm radius) in accordance with DOD-STD-1399, section 071 and
through a hatch 152 cm long by 76 cm wide (reduced further by round corners on
a 19 cm radius). Equipment that is larger may be allowed if significant design
and cost advantages can be realized and special access, such as
cutting/welding the ship's bulkhead, may be authorized for installation.
18.104.22.168 Thermal design and construction. Thermal design shall be in
accordance with requirement 52 of MIL-STD-454 and the guidance of
MIL-HDBK-251. Additional requirements are specified herein. Thermal tests are
specified in Appendix D.
22.214.171.124.1 Cooling method. For surface ships,
the order of preference for cooling is natural convection, forced air cooling,
solid state "cold plates and heat pipes", and, lastly, by chilled water. The
installation may be so that exhaust heat is directed to return air ducts. For
submarines, cooling by chilled water is preferred to forced air cooling to
reduce the acoustic signature of the ship. The method of cooling selected
shall take into account available cooling systems, density, space, weight, and
structureborne noise caused by fans and pumps.
Inlet/outlet location. The inlet air port shall be located not less than 30
cm from the floor.