National Institute for Occupational Safety and Health

“ Zero the balance before each weighing. b. Handle the filter capsule with forceps. Pass the capsule over an antistatic radiation source. Repeat this step if the capsule does not release easily from the forceps or if it attracts balance pan. Static electricity can cause erroneous weight readings. 4.
Assemble the filter capsules in the filter cassettes and close firmly so that leakage around the internal capsule will not occur. Place a plug in each opening of the filter cassette. Place a cellulose shrink band around the filter cassette, allow to dry, and label the cassette with indelible ink. ”

“ Sample at 1 to 2 L/min for a total sample volume of 75 to 1400 L. Do not exceed a filter capsule loading of approximately 5 mg total dust. Take two to four replicate samples for each batch of field samples for quality assurance on the sampling procedure. SAMPLE PREPARATION: 7.
Wipe dust from the external surface of the filter cassette with a moist paper towelette to minimize contamination. Discard the towelette. 8.
Remove the top and bottom plugs from the filter cassette. Equilibrate for at least 24 h in the balance room. 9. ”

“ TLVs and BEIs based on the documentation of the Threshold Limit Values for chemical substances and physical agents and Biological Exposure Indices. Cincinnati, Ohio: American Conference of Governmental Industrial Hygienists. ”