The conductivity of the water extract of electrical grade pulp results from electrolytic impurities in the pulp which may be present as ionizable acids, bases, salts, or a combination of these. The presence of electrolytic impurities in electrical insulation is undesirable as they tend to lower insulation resistance and have corrosion-producing tendencies under conditions of applied potential. When comparing test data it should be noted that the extract conductivity of pulps, especially those of high purity, may change with time after manufacturing. This test is useful for routine acceptance testing, the comparison of different pulps, and research work.

1.1 These test methods cover the sampling and testing of cellulosic pulps for use in the manufacture of electrical insulating papers and boards or in the direct application of pulp fibers as insulation to electrical conductors.

Note 1—The significance of any one pulp property test method, as set forth herein, should be considered with discretion depending on the product made from the pulp.

1.2 Sections on Reagents, Sampling, and Report are integral parts of each of the individual test methods that follow.

1.3 Each test method is described as being a measure of either a bulk property of the pulp or a property of a handsheet formed from the pulp.