Pesticide Barrier Performance of Selected Nonwoven Fabrics in Laboratory Capillary and Pressure Penetration Testing

Abstract

Laboratory spray tests have been used to evaluate the protection offered by two distinct nonwoven fabrics with and without fluorocarbon finishes. The fabrics were contaminated with dicofol field spray mix at coverage levels ranging from 50 to 200 mg/m 2 , values typical of actual field exposures of pesticide spray applicators. Half the samples were subjected to an external compression pressure of 1 psi immediately after contamination (pressure penetration test). The remaining fabrics were allowed to dry without manipulation (capillary penetration test). Increasing contamination level and application of an external mechanical pressure greatly increased the penetration of dicofol through all test fabrics. All four test fabrics provided protection against capillary penetration, usually at levels greater than 99%. In pressure penetration testing, the performance of the two unfinished fabrics was significantly better than that of the finished fabrics.

Conceptual model for assessment of dermal exposure.

“…External air pressure can be considered to be the driving force for penetration of aerosols through fabric, 8 whereas the mechanisms of liquid transport are capillary penetration, pressure penetration, impact penetration, and evaporation-condensation. 9 Mass transport through non-permeable clothing is a diVusion process driven by concentration.…”