42 CFR 84.1147 - Silica mist test for dust, fume, and mist respirators; minimum requirements.
(a) Three non-powered respirators will be tested for a period of 312 minutes each at a continuous airflow rate of 32 liters per minute.
(b) The room temperature in the test chamber will be approximately 25 °C.
(d) Mist will be produced by spraying an aqueous suspension of flint (99 percent free silica), and the flint shall be ground to pass 99 percent through a 270-mesh sieve.
(e) Samples of the test suspension will be taken during each test period for analysis.