Mathematical modeling of electrostatic propensity of protective clothing systems

This work describes a research to develop mathematical models for explaining and predicting the electrostatic propensity of clothing systems worn by human subjects, especially at low humidities. We have developed mathematical equations considering peak potential as a function of fabric system, humidity and temperature, and charge decay as a function of time and time constant. Results correlate well with data from tests based on the proposed ASTM Standard Test Method for Evaluating Tribo-electric (Static) Charge Generation on Protective Clothing Materials (F23.20.05). Additional equations derived to predict peak discharge potential from a capaciitor such as a clothed human body produced good agreement with data from tests following a modified ASTM Method F23.20.05. Charge decay data for two-layer systems from tests following the proposed ASTM Method fit well (R² > 0.90) the exponential model of the form V = V₀ e^-t/τ. Time constants have been determined for various fabrics that make up the different fabric systems tested during our small-scale experiments.