Protective garments: Measurement of the charge decay time of esd-protective garments (NT ELEC 037)

Abstract

  This document specifies a method for determination of the charge decay time for full garments and similar clothing intended as protection for ESD-sensitive components in electronics manufacturing. The method is intended to verify that each panel of the garment has a connection to the ground and the overall continuity of the protective garment. The measurement is performed with the garment worn by a person, which assures that also other phenomena, such as: charge spread out on the complete garment, voltage suppression appearing in real world situations are simulated. The charge can in practical use appear as a result of rubbing (tribocharging) or can be induced when the clothing has been close to a charged object. In the appendix a version of this method is presented for measuring the voltage suppression of a worn garment. This additional method can be used to test a garment if the test object isn’t intended to be grounded when used and has failed the main test. The voltage suppression test could be done simultaneously with the charge decay time test. Therefore, in the method description given in the appendix only those elemements, which are different to the charge decay time test, are given.