Common Terms:
  • Aramid Fibers
  • Break load
  • Denier
  • Electromagnetic Compatibility (EMC)
  • Electromagnetic Interference (EMI)
  • Electromagnetic Pulse (EMP)
  • Indirect Lightning Effects
  • Shielding Effectiveness
  • Transfer Impedance
Aramid Fibers

A class of heat-resistant and strong synthetic fibers. They are used in aerospace and military applications for ballistic rated body armor fabric and ballistic composites, in bicycle tires, and as an asbestos substitute. The name is derived from merging of “aromatic polyamide”. They are fibers in which the chain molecules are highly oriented along the fiber axis, so the strength of the chemical bond can be exploited.

Break load

The force which, when steadily applied to a structure, is just sufficient to break or rupture it.


Unit of measure for the linear mass density of fibers. It is defined as the mass in grams per 9000 meters.

Electromagnetic Compatibility (EMC)

Requires that electronic systems be able to tolerate a specified degree of interference(EMI/EMP/Indirect Lightning Effects) and not generate more than a specified amount of interference.

Electromagnetic Interference (EMI):

Any electromagnetic emission from a device or system that interfere with the normal operation of another device or system.

Electromagnetic Pulse (EMP)

A burst of electromagnetic radiation that results from an explosion (usually from the detonation of a nuclear weapon) and/or a suddenly fluctuating magnetic field.

Indirect Lightning Effects

Refers to the damage to or malfunction of electronic systems that results from a nearby lightning flash.

Shielding Effectiveness

A measure of the reduction or attenuation in electromagnetic field strength at a point in space caused by the insertion of a shield between the source and that point. Usually stated in dB.

Transfer Impedance

Relates a current on the surface of a shield to the voltage drop generated by this current on the opposite surface of the shield. Transfer impedance is used to determine shield effectiveness at lower frequencies (< 1 GHz) against both ingress & engross of interfering signals.