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7.1.3 A description of the test site, including a block diagram with a brief description of the process, location of the sample points in the cross section, dimensions and distances from any point of disturbance.
METHOD 104. REFERENCE METHOD FOR DETER
MINATION OF BERYLLIUM EMISSIONS FROM STATIONARY SOURCES
1. Principle and applicability-1.1 Principle.-Beryllium emissions are isokinetically sampled from the source, and the collected sample is digested in an acid solution and analyzed by atomic absorption spectrophotometry.
1.2 Applicability. This method is applicable for the determination of beryllium emissions in ducts or stacks at stationary sources. Unless otherwise specified, this method is not intended to apply to gas streams other than those emitted directly to the atmosphere without further processing.
2. Apparatus-2.1 Sampling train.-A schematic of the sampling train used by EPA is shown in figure 104-1. Commercial models of this train are available, although construction details are described in APTD0581,1 and operating and maintenance procedures are described in APTD-0576. The components essential to this sampling train are the following:
2.1.1 Nozzle.-Stainless steel or glass with sharp, tapered leading edge.
2.1.2 Probe.—Sheathed Pyrexo glass. A heating system capable of maintaining a minimum gas temperature in the range of the stack temperature at the probe outlet during sampling may be used to prevent condensation from occurring.
2.1.3 Pitot tube.-Type S (figure 104–2), or equivalent, with a coefficient within 5 percent over the working range, attached to probe to monitor stack gas velocity.
2.1.4 Filter holder.-Pyrex glass. The filter holder must provide a positive seal against leakage from outside or around the filter. A heating system capable of maintaining the filter at a minimum temperature in the range of the stack temperature may be used to prevent condensation from occurring.
2.1.5 Impingers.-Four Greenburg-Smith impingers connected in series with glass ball joint fittings. The first, third, and fourth impingers may be modified by replacing the tip with a 1/2-inch i.d. glass tube extending to one-half inch from the bottom of the flask.
2.1.6 Metering system.-Vacuum gauge, leakless pump, thermometers capable of measuring temperature to within 6° F, dry gås meter with 2 percent accuracy, and related equipment, described in APTD-0581, to maintain an isokinetic sampling rate and to determine sample volume.
1 These documents are available for a nominal cost from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Road, Springfield, Va. 22151.
2 Mention of trade names on specific products does not constitute endorsement by the Environmental Protection Agency.
2.1.7 Barometer.-TO measure atmospheric pressure to + 0.1 in Hg.
2.2 Measurement of stack conditions (stack pressure, temperature, moisture and velocity)-2.2.1 Pitot tube.-Type S, equivalent, with a coefficient within 5 percent over the working range.
2.2.2 Differential pressure gauge.--Inclined manometer, or equivalent, to measure velocity head to within 10 percent of the minimum value.
2.2.3 Temperature gage.-Any temperature measuring device to measure stack temperature to within 5° F.
2.2.4 Pressure gage.-Pilot tube and inclined manometer, or equivalent, to measure stack pressure to within 0.1 in Hg.
2.2.5 Moisture determination.--Wet and dry bulb thermometers, drying tubes, condensers, or equivalent, to determine stack gas moisture content within 1 percent.
2.3 Sample recovery-2.3.1 Probe cleaning rod.-At least as long as probe.
2.3.2 Leakless glass sample bottles.-500 ml.
2.3.3 Graduated cylinder.-250 ml.
2.4 Analysis-2.4.1 Atomic absorption spectrophotometer.—To measure absorbance at 234.8 nm. Perkin Elmer Model 303, or equivalent, with N,0/acetylene burner. 2.4.2 Hot plate. 2.4.3 Perchloric acid fume hood.
3. Reagents—3.1 Stock Teagents.-3.1.1 Hydrochloric acid. Concentrated.
3.1.2 Perchloric acid.-Concentrated, 70 percent.
3.1.3 Nitric acid.-Concentrated. 3.1.4 Sulfuric acid.- Concentrated. 3.1.5 Distilled and deionized water.
3.1.6 Beryllium powder.-98 percent minimum purity.
3.2 Sampling-3.2.1 Filter. Millipore AA, or equivalent. It is suggested that a Whatman 41 filter be placed immediately against the back side of the Millipore filter as a guard against breaking the Millipore
filter. In the analysis of the filter, the Whatman 41 filter should be included with the Millipore filter.
3.2.2 Silica gel.-Indicating type, 6 to 16 mesh, dried at 350° F for 2 hours.
3.2.3 Distilled and deionized water.
3.3 Sample recovery-3.3.1 Distilled and deionized water.
3.3.2 Acetone.—Reagent grade.
3.3.3 Wash acid.-1.1 V/V hydrochloric acid-water.
3.4 Analysis.-3.4.1 Sulfuric acid solution, 12 N.-Dilute 333 ml of concentrated sulfuric acid to 1 l with distilled water.
3.4.2 25 percent V/V hydrochloric acidwater.
3.5 Standard beryllium solution-3.5.1 stock solution.-1 ug/ml beryllium. Dissolve 10 mg of beryllium in 80 ml of 12 N sulfuric acid solution and dilute to a volume of 1000 ml with distilled water. Dilute a 10 ml aliquot to 100 ml with 25 percent V/V hydrochloric acid, giving a concentration of 1 Mg/ml. This dilute stock solution should be prepared fresh daily. Equivalent strength (in beryllium) stock solutions may be prepared from beryllium salts as BeCl, and Be(NO3), (98 percent minimum purity).
4. Procedure. 4.1 Guidelines for source testing are detailed in the following sections. These guidelines are generally applicable; however, most sample sites differ to some degree and temporary alterations such as stack extensions or expansions often are required to insure the best possible sample site. Further, since beryllium is hazardous, care should be taken to minimize exposure. Finally, since the total quantity of beryllium to be collected is quite small, the test must be carefully conducted to prevent contamination or loss of sample.
4.2 Selection of a sampling site and minimum number of traverse points.
4.2.1 Select a suitable sampling site that Is as close as practicable to the point of atmospheric emission. If possible, stacks smaller than 1 foot in diameter should not be sampled.
4.2.2 The sampling site should be at least 8 stack or duct diameters downstream and 2 diameters upstream from any flow disturbance such as a bend, expansion or contraction. For a rectangular cross-section, determine an equivalent diameter from the following equation:
eq. 104-1 where: D.=equivalent diameter
4.2.3 When the above sampling site criteria can be met, the minimum number of traverse points is four (4) for stacks 1 foot in diameter or less, eight (8) for stacks larger than 1 foot but 2 feet in diameter or less, and twelve (12) for stacks larger than 2 feet.
Figure 101-3. Minimum number of traverse points.
tical. When this is the case, choose a convenient sampling location and use figure 104-3 to determine the minimum number of traverse points. However, use figure 1043 only for stacks 1 foot in diameter or larger.
4.2.5 To use figure 104-3, first measure the distance from the chosen sampling location to the nearest upstream and downstream disturbances. Divide this distance by
the diameter or equivalent diameter to deterFigure 104-4. Cross section of circular stack showing location of
mine the distance in terms of pipe diameters. traverse points on perpendicular diameters.
Determine the corresponding number of traverse points for each distance from figure 104–3. Select the higher of the two numbers of traverse points, or a greater value, such that for circular stacks the number is a multiple of four, and for rectangular stacks the number follows the criteria of section 4.3.2.
4.2.6 II a selected sampling point is closer than 1 inch from the stack wall, adjust the
location of that point to ensure that the Figure 104-5. Cross section of rectangular stack divided into 12 equal sample is taken at least 1 inch away from the areas, with traverse points at centroid of each area.
wall. 4.2.4 Some sampling situations may ren
4.3 Cross-sectional layout and location of der the above sampling site criteria imprac- traverse points.
Table 104-1. Location of traverse points in circular stacks
1 2 3 4
9 10 11 12 13 14 15 16 17 18
14.6 6.7 4.4 3.3 2.5 2.1 1.8 1.6 1.4 1.3 1.1
1.1 85.4 25.0 14.7 10.5 8.2 6.7
4.9 4.4 3.9 3.5 3.2 75.0 29.5 19.4 14.6 11.8 9.9 8.5. 7.5 6.7 6.0 5.5 93.3 | 70.5 32.3 22.6 17.7 14.6 12.5 10.9 9.7 8.7 7.9
85.3 67.7 34.2 25.0 20.1 16.9 14.6 | 12.9 11.6 10.5 95.6 80.6 65.8 35.5 26.9 22.0 | 18.8 16.5 14.6 13.2
89.5 77.4 64.5 36.6 28.3 23.6 20.4 18.0 16.1 96.785.475.0 63.4 37.5 29.6 25.0 21.8 19.4
91.8 82.3 73.1 62.5 38.2 30.6 26.1 23.0 97.5 88.2 79.9 71.7 61.8 38.8 31.5 27.2
93.3 85.478.070.4 61.239.3 32.3 97.9 90.1 83.176.4 | 69.4 60.7 39.8
94.3 87.5 81.2 75.0 68.5 60.2 98.291.5 85.4 79.6 73.9 67.7°
95.1 | 89.1 83.5 | 78.2 72.8 * 98.4 92.5 87.1 82.0 77.0
95.6 90.3 85.4 80.6 98.6 93.3 | 88.4 83.9
96.1 91.3 86.8 98.7 94.0 89.5
96.5 92.1 98.9 | 94.5
22 23 24
4.3.1 For circular stacks locate the traverse points on at least two diameters according to figure 104-4 and table 104-1. The traverse axes shall divide the stack cross section into equal parts.
4.3.2 For rectangular stacks divide the Cross section into as many equal rectangular areas as traverse points, such that the ratio of the length to the width of the elemental areas is between 1 and 2. Locate the traverse points at the centroid of each equal area according to figure 104-6.
4.4 Measurement of stack conditions.4.4.1 Set up the apparatus as shown in figure 104–2. Make sure all connections are tight and leak free. Measure the velocity head and temperature at the traverse points specified by $84.2 and 4.3.
4.4.2 Measure the static pressure in the stack.
4.4.3 Determine the stack gas moisture.
4.4.4 Determine the stack gas molecular weight from the measured moisture content and knowledge of the expected gas stream composition. A standard Orsat analyzer has been found valuable at combustion sources. In all cases, sound engineering judgment should be used.
4.5 Preparation of sampling train.-4.5.1 Prior to assembly, clean all glassware (probe, Impingers, and connectors) by soaking in wash acid for 2 hours. Place 100 mil of distilled water in each of the first two impingers, leave the third impinger empty, and place approximately 200 g of preweighted silica gel in the fourth impinger. Save a portion of the
the temperature of the gases leaving the last impinger at 70° F. or less.
4.6 Beryllium train operation.-4.6.1 For each run, record the data required on the example sheet shown in figure 104-6. Take readings at each sampling point at least every 5 minutes and when significant changes in stack conditions necessitate additional adjustments in flow rate.
4.6.2 Sample at a rate of 0.5 to 1.0 ft./min. Samples shall be taken over such a period or periods as are necessary to accurately determine the maximum emissions which would occur in & 24-hour period. In the case of cyclic operations, sufficient tests shall be made so as to allow accurate determination or calculation of the emissions which will occur over the duration of the cycle. A minimum sample time of 2 hours is recommended.
AMBIENT TEMPERATURE BAROMETRIC PRESSURE
ASSUMED MOISTURE, %
HEATER BOX SETTING
PROBE LENGTH, M.,
NOZZLE DIAMETER, in, PROBE HEATER SETTING
GAS SAMPLE TEMPERATURE
AT DRY GAS METER
SAMPLE BOX IMPINGER TEMPERATURE, TEMPERATURE °F
distilled water as a blank in the sample analysis. Set up the train and the probe as in figure 104-1.
4.5.2 Leak check the sampling train at the sampling site. The leakage rate should not be in excess of 1 percent of the desired sampling rate. If condensation in the probe or filter is & problem, probe and filter heaters will be required. Adjust the heaters to provide a temperature at or above the stack temperature. However, membrane filters such as the Mullipore AA are limited to about 225° F. If the stack gas is in excess of about 200° F., consideration should be given to an alternate procedure such as moving the filter holder downstream of the first impinger to insure that the filter does not exceed its temperature limit. Place crushed ice around the impingers. Add more ice during the test to keep
SAMPLE BOX NO
METER BOX NO.
2 C FACTOR
SCHEMATIC OF STACK CROSS SECTION
IPS!. in. Ha
Figure 104-6. i Field data
4.6.3 To begin sampling, position the 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 6 minutes at each traverse point; sampling time must be the same for each point. Maintaln isokinetic sampling throughout the sampling period. Nomographs which aid in the rapid adjustment of the sampling rate without other computations are in APTD-0576 and are available from commercial suppliers. Note that standard monographs are applicable only for type S pitot tubes and air or a stack gas with an equivalent density. Contact EPA or the sampling train supplier for
instructions when the standard monograph is not applicable.
4.6.4 Turn off the pump at the conclusion of each run and record the final readings. Immediately remove the probe and nozzle from the stack and handle in accordance with the sample recovery process described in $ 4.7.
4.7 Sample recovery.-4.7.1 (All glass storage bottles and the graduated cylinder must be precleaned as in $ 4.5.1.) This operation should be performed in an area free of possible beryllium contamination. When the sampling train is moved, care must be exercised to prevent breakage and contamination.
4.7.2 Disconnect the probe from the impinger train. Remove the filter and any loose