Assigned protection factors for two respirator types based upon workplace performance testing.
Ann Occup Hyg 1984; 28(2):173-182
Protection factors assigned to two respirator types were evaluated based on workplace performance. Protection factors were measured for a half mask, negative pressure, air purifying respirator with high efficiency filters and a half mask powered, air purifying respirator with high efficiency filters. The sinter facility and blast furnace area of a primary lead (7439921) smelter provided the workplace setting. Protection factors were determined from analysis of lead in the environment as a representative of the total challenge aerosol. Respirator face pieces were correctly fitted to subjects. Lead concentrations were measured simultaneously inside and outside the respirator for a normal 8 hour work shift using sample trains of a Millipore cassette with filters and a personal sampling pump. Lead on sample filters was determined by atomic absorption spectroscopy. The protection factor was expressed as lapel concentration divided by mask concentration. Protection factors for the negative pressure respirator ranged from a high of 2200 for a sinter helper, to a low of 10 for a blast furnace operator and the low was 23 for a sinter room mixer. The protection factors for both types of respirator were adequately described by log normal distributions. The authors conclude that the currently assigned protection factor of 10 is appropriate for the negative pressure air purifying respirator in usual conditions. The currently assigned 500 factor is excessive for the powered respirator and a factor of 50 would be more appropriate.
NIOSH-Author; Safety-equipment; Equipment-reliability; Quantitative-analysis; Protective-equipment; Toxic-vapors; Industrial-equipment; Health-protection; Control-methods; Respiratory-equipment; Equipment-design; Research
Annals of Occupational Hygiene