Effect of using a cowl when measuring the fiber number concentration by the membrane filter method.
This article compares samples taken with three different sampling heads: (1). open-faced sampling head, (2). open-faced sampling head with stainless-steel extension cowl, and (3). open-faced sampling head with graphite-impregnated extension cowl. Sampling was performed in three factories producing man-made mineral fibers (alkaline silicate fibers, refractory ceramic fibers, glass fibers). Flow rate was varied (1 L/min or 2 L/min). The average densities measured on the sampling filter for fibers of <3 microm in diameter varied from 19 to 91 fibers/mm(2). No significant difference in fiber density was observed in relation to the nature of the sampling head for fibers with a diameter of <3 microm. The deposits noted on the internal walls of the cowl were small and much less than that documented in the literature for man-made mineral fibers until now. They were greater for fibers with a diameter of >3 microm than for those with a diameter of <3 microm. For large-diameter fibers, it would appear that cowl deposit can be reduced by increasing the sampling flow rate.
Kauffer
Edmond
E
Institut National de Recherche et de Sécurité, Vandoeuvre-lès-Nancy, France. edmond.kauffer@inrs.fr
Eypert-Blaison
Céline
C
D000395:Air Pollutants, Occupational / Q000032:analysis*; D004867:Equipment Design; D005374:Filtration / Q000295:instrumentation*; D006801:Humans; D019016:Mineral Fibers / Q000032:analysis*
D000395:Air Pollutants, Occupational; D019016:Mineral Fibers