Different test methods for evaluating hazards resulting from static charge development and static charge decay on protective clothing materials have been developed. These test methods involve both the application of electrical charge and the measurement of surface resistivity by means of surface electrodes. Misleading information can be produced utilizing the electrode charge decay method when a material has low conductivity. When a material has low conductivity, it is possible that either no charge is developed, or anomalous readings of static charge occur when in actuality no charging or discharging of the material has taken place. In addition, these methods do not employ techniques which simulate the conditions of actual use of a material.
The triboelectric method developed by the National Aeronautics and Space Administration (NASA), can be utilized to circumvent some of the shortcomings of the electrode methods. With the triboelectric method, static charge is developed on the test material by means of rubbing friction, thus simulating the manner of actual use of the protective garment. Reproducible application of static charge can be accomplished by way of a polytetrafluoroethylene (PTFE) felt wheel which is rubbed against the test specimen for ten seconds. The peak voltage and charge decay rate for five seconds after cessation of rubbing are recorded. This paper gives a complete description of the test method, its development, applications, and provides results on a series of sample materials using this technique. Results of the triboelectric test method are also compared against other industry standards.