May 1, 1977

STATE OF WASHINGTON DEPARTMENT OF ECOLOGY

SOURCE TEST METHOD 8 

PARTICULATE SAMPLING BY AN IMPINGER TRAIN 

1. Principle

This method utilizes condensation and impingement to collect .a particulate sample. 

2. Description

The stack gases are sampled isokinetically while traversing the stack. Particulate is collected 

by a series of Greenburg-Smith impingers. The sample gas volume is determined by a 

totalizing gas meter. The amount of particulate collected is determined by evaporating the 

impinger catch to dryness. This method should only be used on stacks with less than 5 ppm 

SO2' 

3. Equipment and Reagents

Equipment: 

a. Stainless steel nozzle at least 1/4 inch in diameter. 

b. Stainless steel probe. 

c. Flexible nonreactive tubing such as Teflon. 

d. Condensate system comprised of three Greenburg-Smith impingers and drying 

 tube. The first and third impingers can be modified by replacing the tip with 

 half-inch I.D. glass tube extending to one-half inch of the bottom of the flask. 

e. Leakless valve to regulate flow. 

f. Leakless pump. 

g. Dry test gas meter with thermometer to indicate temperatures. 

h. Liquid storage containers. 

i. 250 ml graduated cylinder. 

j. Balance capable of weighing 300 gm ±0.5 gm. 
DOE Source Test Method 8 

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k. Analytical balance to weigh the weighing dish ±0.5 mg. 

l. Weighing dish. 

m. Oven to maintain 105°C ±5°C. 

Reagents: 

a. Indicating type silica gel, or equivalent. 

b. Distilled water.. 

c. Crushed ice. 

4. Procedures

Using the DOE Methods to obtain representative points, measure the stack pressure, 

temperature, moisture and range of velocity head. On the first run, the moisture may be 

estimated. 

Preparation of Sampling Train: Place 100ml of water in each of the first two impingers. Leave 

the third impinger empty and place at least 200g. preweighed to the nearest 0.5g. of silica gel 

in the drying tube. Set up the train as in Figure 1. Leak-check the sampling train by plugging 

the nozzle. A leakage rate not in excess of 0.02 cfm is acceptable. The nozzle, pitot tip and 

the thermocouple tip should be in the same plane at least 3/4-inch apart. Place crushed ice 

around the impingers. Add more ice during the run to keep the temperatures of the gases, 

leaving the last impinger as low as possible, preferably at 70°F or less. 

Train operation: For each run, record necessary data; such as, location, time, date, operator, 

nozzle diameter, initial impinger volume, and relevant process information. At each sampling 

point, and when significant changes in operating conditions necessitate, take readings such 

as traverse point, sampling time, stack temperature, and velocity pressure. Record 

temperatures within at least 5°F and pressure ±10%. To begin sampling, position nozzle at 

the first traverse point with the tip pointing directly into the gas stream. Immediately start the 

pump and adjust the flow to isokinetic conditions. Sample for at least two minutes at each 

traverse point. Sampling time should be the same for each point, unless some points 

represent more area than others. In such a case, sample proportionally longer at these 

points. Adjust the sampling rate to isokinetic as necessary. Turn off the pump at the 

conclusion of the run and record the final readings. Remove the probe and nozzle from the 

stack. 

Sample Recovery: When the sampling period is over, turn off the pump, record the final 

meter readings, and remove the probe from the stack. Measure the condensate volume and 

place it in a suitable container. Also place the silica gel in a suitable air tight container. Rinse 

the probe with distilled water into the container with the impinger catch. 
.DOE Source Test Method 8 

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5. Analysis and Calculation

Analysis: 

Dry the impinger catch, less any aliquot taken for chemical analysis, at 105°C. For example, 

samples from kraft recovery furnace stacks might be analyzed for sodium, calcium, 

magnesium and potassium. 

Calculation: 

Calculate the particulate concentration by dividing the weight of the impinger catch by the 

volume sampled corrected to standard conditions. The stack moisture is determined from the 

volume of condensate unless the stack is saturated. If the stack is saturated, then moisture is 

determined by saturation as in DOE Method 4. 

6. Calibration

The dry gas meters should be calibrated against a wet test meter. If the correction is greater 

than 2%, adjust the dry gas meter until the correction is less than 2%. 

Calibrate temperature gages against a standard thermometer for at least two points; i.e., an 

ice bath and boiling water. The gage should read within 1.5% of the absolute temperature. 

Barometers should be calibrated against a mercury barometer. 

Calibrate pitot tubes against a standard pitot over the normal working range. The pitot 

coefficient should not differ by more than 0.01 for each side. 

7. References

a. "Comparison of Source Particulate with Emissions Measurement Methods at Lime Kilns 

and Smelt Dissolving Tank Vent Stacks." NCASI Atmospheric Quality Improvement 

Technical Bulletin No. 68, New York, May 1973.