Page:NIOSH Manual of Analytical Methods - 5000.pdf/2

 CARBON BLACK: METHOD 5000, Issue 2, dated 15 August 1994 - Page 2 of 4 EQUIPMENT: 1. Sampler: 37-mm, 5-µm pore size PVC filter and stainless steel support screen in 37-mm, cassette filter holder (preferably, conductive). 2. Personal sampling pump, 1 to 2 L/min, with flexible connecting tubing. 3. Microbalance capable of weighing to 0.001 mg. 4. Static neutralizer; e.g. Po-210; replace nine months after production date. 5. Forceps (preferably nylon). 6. Environmental chamber or room for balance (e.g. 20 ± 1 °C and 50 ± 5% RH).

SPECIAL PRECAUTIONS: Carbon black containing polynuclear aromatic hydrocarbons (cyclohexane extractable materials) in excess of 0.1% (w/w) should be treated as a suspect carcinogen [3].

PREPARATION OF FILTERS BEFORE SAMPLING: 1. 2. 3.

4.

Equilibrate the filters in an environmentally controlled weighing area or chamber for at least 2 h. NOTE: An environmentally controlled chamber is desirable, but not required. Number the backup pads with a ballpoint pen and place them, numbered side down, in filter cassette bottom sections. Weigh the filters in an environmentally controlled area or chamber. Record the filter tare weights, W 1, (mg). a. Zero the balance before each weighing. b. Handle the filter with forceps. Pass the filter over an antistatic radiation source. Repeat this step if filter does not release easily from the forceps or if filter attracts balance pan. Static electricity can cause erroneous weight readings. Assemble the filters in the filter cassettes and close firmly so that leakage around the filter 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 mark with the same number as the backup pad.

SAMPLING: 5. 6.

Calibrate each personal sampling pump with a representative sampler in line. Sample at 1 to 2 L/min for a total sample volume of 30 to 570 L. Do not exceed a filter loading of approximately 2 mg total dust. Take two to four replicate samples for each batch of field samples for quality assurance on the sampling procedures.

SAMPLE PREPARATION: 7. 8. 9.

Wipe dust from the external surface of the filter cassette with a moist paper towel to minimize contamination. Discard the paper towel. Remove the top and bottom plugs from the filter cassette. Equilibrate for at least 2 h in the balance room. Remove the cassette band, pry open the cassette, and remove the filter gently to avoid loss of dust. NOTE: If the filter adheres to underside of cassette top, gently lift using the dull side of scalpel blade. Take care not to tear the filter.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94