Trouble shooting guide for the periodic in-place leak testing of HEPA filters and carbon absorbers

The guide was developed to aid in solving problems that occur during periodic in-place leak testing of HEPA filters and carbon adsorbers. Due to the wide range of problems that can occur and the differences in test equipment, filter system, and testing technique, it becomes almost impossible to address every problem. The purpose of this guide is to provide an approach to finding and solving most filter testing problems. Certain assumptions were made concerning the types of equipment used and the types of tests performed. The following information is assumed: the particulate filters are HEPA filters; gas adsorber filters use impregnated activated carbon as the adsorbant; the challenge agent for testing the HEPA filters is dioctyl phthalate (DOP) aerosol; the challenge agent for testing the carbon adsorbers is refrigerant 11 (R-11); leak detection equipment for the DOP is a forward light scattering photometer; and leak detection equipment for the R-11 is a gas chromatograph. Deviations from these assumptions must be taken into account when using the guide