ASTM D2624 method for electrical conductivity of aviation and distillate fuels
1. Scope
1.1 These test methods cover the determination of the electrical conductivity of aviation and distillate fuels with and without a static dissipator additive. The test methods normally give a measurement of the conductivity when the fuel is uncharged, that is, electrically at rest (known as the rest conductivity).
1.2 Two test methods are available for field tests of fuel conductivity. These are: (1) portable meters for the direct measurement in tanks or the field or laboratory measurement of fuel samples, and (2) in-line meters for the continuous measurement of fuel conductivities in a fuel distribution system. In using portable meters, care must be taken in allowing the relaxation of residual electrical charges before measurement and in preventing fuel contamination.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see 7.1, 7.1.1, and 11.2.1.
2. Referenced Documents
2.1 ASTM Standards:
D4306 Practice for Aviation Fuel Sample Containers for Tests Affected by Trace Contamination
D4308 Test Method for Electrical Conductivity of Liquid Hydrocarbons by Precision Meter
3. Terminology
3.1 Definitions:
3.1.1 picosiemens per metre, n - the unit of electrical conductivity is also called a conductivity unit (CU). A siemen is the SI definition of reciprocal ohm sometimes called mho.
1 pS/m = 1 x 10(-12) Ω(-1) m(-1) = 1 cu = 1 picomho/m
3.1.2 rest conductivity, n - the reciprocal of the resistivity of uncharged fuel in the absence of ionic depletion or polarization.
3.1.2.1 Discussion - It is the electrical conductivity at the initial instant of current measurement after a dc voltage is impressed between electrodes, or a measure of the average current when an alternating current (ac) voltage is impressed.
