SOLID PARTICLE PENETRATION INTO ENCLOSURES

Protection factors against toxic vapors for enclosures such as vehicles and shelters are commonly evaluated on the basis of the behavior of a simulant vapor. Mechanisms influencing protection against solid particles have yet to be integrated into integrity-testing procedures. The scarcity of empirical studies which could provide the basis for such procedures suggested a program whose objectives would be to provide means for measuring size-dependent solid particle protection factors for various exposure scenarios and for expressing the relevant mechanisms in model calculations. These could then aid in the design of such procedures. A system providing a flexible infrastructure for experimenting with controlled challenge scenarios was assembled outdoors in an open-ended agricultural cloche. A sealed enclosure located at the end of the cloche far from the dissemination apparatus enabled testing of solid particle challenge penetration through well-defined apertures under controlled ventilation dynamics. A computer model was written to calculate protection factors for vapor and solid particles using both theoretical models and empirical data. The experimental system provided data for the calibration and verification of the model.