AATCC 76:2000 pdf download.Electrical Surface Resistivity of Fabrics
6.1 Adjust the size of fabric test speci- mens to suit the electrodes of the particu- lar equipment being used. When using parallel plate electrodes, the width of the specimen must not exceed the width of the electrodes. W hen using the concentric rings, any size specimen at least as large as the outer ring may be used. Avoid con- taminating the area on which the mea- surement is to be made.
6.2 Specimens for use with instruments providing parallel plate electrodes. Pre- pare 2 sets of 3 test specimens each, 1 set each so that the direction of testing is par- allel to the yarns in the length direction of the fabric and 1 set with the direction of testing parallel to the width direction of the fabric.
6.2.1 Test specimens for use with in- struments providing concentric ring elec- trodes. Prepare 1 set (3 test specimens) since, with this type instrument, the resis- tance is measured in both fabric length and fabric width directions simulta- neously.
6.2.2 Depending on the fabric con- struction or end-use, it may be advisable to differentiate between face and back measurements. Each test specimen should be taken from a different part of the fabric.
7. Procedure
7.1 Calibrate the electrical resistance meter according to the manufacturer's recommendations. This calibration should be repeated periodically (see 10.3).
7.2 Condition the test specimens in a suitable testing chamber or conditioning room at a predetermined relative humid- ity that will reflect the conditions at which information on the electrical resis- tivity of the fabric is needed.
7.2.1 For most fabrics which require an- tistatic treatments or whose static propen- sity is critical, measurements at 20% rela- tive humidity will be most meaningful.
7.2.2 In less critical situations 40% rel- ative humidity may be employed.
7.2.4 If it is necessary to measure elec- trical resistivity under a broad range of conditions, additional tests may be run at 65% RH and at 24°C or other settings ap- plicable to the end use. It is preferable to keep the temperature or humidity consis- tent for all measurements.AATCC 76 pdf download.