1.1 These test methods cover three procedures for determination of the permeability [relative permeability] of materials having a permeability not exceeding 4.0. 1.2 The test methods covered are as follows: 1.2.1 Test Method 1 is suitable for materials with permeabilities between 1.0 and 4.0. 1.2.2 Test Method 2 is suitable for measuring the permeability of paramagnetic materials having a permeability less than 1.05. 1.2.3 Test Method 3 is a suitable means of measuring the permeability of a material as "less than" or "greater than" that of calibrated standard inserts designated for use in a Low-Mu Permeability Indicator. 1.3 The values stated in either customary (absolute (or practical) cgs-emu and inch-pound) units or SI units are to be regarded separately as standard. Within this test method, the SI units are shown in brackets except for the sections concerning calculations where there are separate sections for the respective unit systems. The values stated in each system are not exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with this specification. 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.