General. Gaskets covered by this specification are designed to provide EMI/RFI shielding, EMP survivability, and environmental protection for electronic enclosures, connectors, and waveguides. Their principal areas of application are aircraft, missiles, spacecraft, and ground support equipment. This does not preclude the use of these gaskets in other military applications.

Salt spray environments. All EMI gasket materials (metal and elastomer) to varying degrees are incompatible with certain flange surfaces. Design of the joint, therefore, plays a central role in determining the electrical stability and corrosion resistance of the joint. Design variables include: Flange material and finish, gasket filler and form (sheet, O-ring in a groove), use of parallel nonconductive environmental gaskets, mechanical design, and use of insulating coatings. Choice of the design options should depend on: Environment of the application, levels of shielding effectiveness required versus frequency, and expected life of the equipment. When designing for salt spray environments, all of the preceding factors must be considered.

Vibration environments. Type M material may be suitable for high-frequency vibration applications.

Shielding effectiveness. IEEE-STD-299 has been considered an acceptable method for determining shielding effectiveness as modified and supplemented by figure 4.