A Laboratory Protocol to Assess the Electrostatic Propensity of Protective-clothing Systems

Abstract

The ability to predict the electrostatic propensity of textile systems has been an elusive goal for many years. Some small-scale test methods previously reported were found to be inadequate for certain conditions. One of the most serious problems is poor correlation between test measurements and the values of electrostatic discharges from a clothed person in real-life situations. This paper describes the development of a laboratory protocol to evaluate the electrostatic properties of clothing systems Four small-scale tests were evaluated and compared in order to select a protocol that could best assess the static propensity of protective-garment systems worn by workers in hazardous environments under dry conditions. Several two-layer fabric systems that included non-FR (non-fire-retardant) cotton, as well as thermal-protective fabrics of aramid fibre/carbon, aramid fibre/PBI (polybenzimidazole) fibre, aramid fibre/FR viscose, and FR cotton, were tested. Experiments were conducted at room temperature and 0% and 20% relative humidity (r.h.). Fabrics were evaluated in terms of both peak discharge potentials and charge decay. These peak potentials and charge decays were compared with data from human-body experiments, and significant coefficients of determination (R 2) of up to 0.99 were found when results from different tests were regressed on human-body data. It therefore seems that measuring peak discharge potentials and charge decays from charged-fabric systems and peak discharge potentials from a capacitor by using a battery of test methods can be sufficient to assess, with high accuracy, the static behaviour of garment systems in real-life conditions.