may be used to determine the rotation angles in lieu of the procedure described above.

2.5 Alternative Measurement Site Selection Procedure. This alternative applies to sources where measurement locations are less than 2 equivalent stack or duct diameters downstream or less than 1/2 duct dlameter upstream from a flow disturbance. The alternative should be limited to ducts larger than 24 in. in diameter where blockage and wall effects are minimal. A directional flowsensing probe is used to measure pitch and yaw angles of the gas flow at 40 or more traverse points; the resultant angle is calculated and compared with acceptable criteria for mean and standard deviation. NOTE: Both the pitch and yaw angles are measured from a line passing through the traverse point and parallel to the stack axis. The pitch angle is the angle of the gas flow component in the plane that INCLUDES the traverse line and is parallel to the stack axis. The yaw angle is the angle of the gas flow component in the plane PERPEN- DICULAR to the traverse line at the traverse point and is measured from the line passing through the traverse point and parallel to the stack axis. 2.5.1 Apparatus. 2.5.1.1 Directional Probe. Any directional probe. such as United Sensor Type DA Three- Dimensional Directional Probe, capable of measuring both the pitch and yaw angles of gas flows is acceptable. (NOTE Mention of trade name or specific products does not constitute endorsement by the U.S. Environmental Protection Agency.) Assign an identification number to the directional probe, and permanently mark or engrave the number on the body of the probe. The pressure holes of directional probes are susceptible to plugging when used in particulate-laden gas streams. Therefore, a system for cleaning the pressure holes by "back-purging" with pressurized air is required. 2.5.1.2 Differential Pressure Gauges. Inclined manometers, U-tube manometers, or other differential pressure gauges (e.g., magnehelic gauges) that meet the specifications described in Method 2. section 2.2. NOTE: If the differential pressure gauge produces both negative and positive readings. then both negative and positive pressure readings shall be calibrated at a minimum of three points as specified in Method 2. section 2.2. 2.5.2 Traverse Points. Use a minimum of 40 traverse points for circular ducts and 42 points for rectangular ducts for the gas flow angle determinations. Follow section 2.3 and Table 1-1 or 1-2 for the location and layout of the traverse points. If the measurement location is determined to be acceptable according to the criteria in this alternative procedure. use the same traverse point number and locations for sampling and velocity measurements. 2.5.3 Measurement Procedure. 2.5.3.1 Prepare the directional probe and differential pressure gauges as recommended by the manufacturer. Capillary tubing or surge tanks may be used to dampen pressure fluctuations. It is recommended, but not required, that a pretest leak check be conducted. To perform a leak check, pressurize or use suction on the impact opening until a reading of at least 7.6 cm (3 in.) H 20 registers on the differential pressure gauge. then plug the impact opening. The pressure of a leakfree system will remain stable for at least 15 seconds. 2.5.3.2 Level and zero the manometers. Since the manometer level and zero may drift because of vibrations and temperature changes, periodically check the level and zero during the traverse. 2.5.3.3 Position the probe at the appropriate locations in the gas stream, and rotate until zero deflection is indicated for the yaw angle pressure gauge. Determine and record the yaw angle. Record the pressure gauge readings for the pitch angle, and determine the pitch angle from the calibration curve. Repeat this procedure for each traverse point. Complete a "back-purge" of the pressure lines and the impact openings prior to measurements of each traverse point. A post-test check as described in section 2.5.3.1 is required. If the criteria for a leakfree system are not met, repair the equipment, and repeat the flow angle measurements. 2.5.4 Calculate the resultant angle at each traverse point, the average resultant angle, and the standard deviation using the following equations. Complete the calculations retaining at least one extra significant figure beyond that of the acquired data. Round the values after the final calculations. 2.5.4.1 Calculate the resultant angle at each traverse point: R,=arc cosine [(cosine )(cosine PJJ Eq. 1-2 Where: R,=Resultant angle at traverse point i, degree. Y,=Yaw angle at traverse point 1, degree. P,=Pitch angle at traverse point 1, degree. 2.5.4.2 Calculate the average resultant for the measurements: EC16NO91.107 Where: R=Average resultant angle, degree. n=Total number of traverse points. 2.5.4.3 Calculate the standard deviations: EN30AU93.031 Eq. 1-4 Where: S&-Standard deviation. degree. 2.5.5 -The measurement location is acceptable if Rs20° and Sas10°. 2.5.6 Calibration. Use a flow system as described in Sections 4.1.2.1 and 4.1.2.2 of Method 2. In addition, the flow system shall have the capacity to generate two test-section velocities: one between 365 and 730 m/min (1200 and 2400 ft/min) and one between 730 and 1100 m/min (2400 and 3600 ft/min). 2.5.6.1 Cut two entry ports in the test section. The axis through the entry ports shall be perpendicular to each other and intersect in the centroid of the test section. The ports should be elongated slots parallel to the axis of the test section and of sufficient length to allow measurement of pitch angles while maintaining the pitot head position at the test-section centroid. To facilitate alignment of the directional probe during calibration, the test section should be constructed of plexiglass or some other transparent material. All callbration measurements should be made at the same point in the test section. preferably at the centroid of the test section. 2.5.6.2 To ensure that the gas flow is parallel to the central axis of the test section, follow the procedure in Section 2.4 for cyclonic flow determination to measure the gas flow angles at the centroid of the test section from two test ports located 90° apart. The gas flow angle measured in each port must be +2° of 0°. Straightening vanes should be installed, if necessary, to meet this criterion. 2.5.6.3 Pitch Angle Calibration. Perform a calibration traverse according to the manufacturer's recommended protocol in 5° Increments for angles from -60° to =60° at one velocity in each of the two ranges specified above. Average the pressure ratio values obtained for each angle in the two flow ranges, and plot a calibration curve with the average values of the pressure ratio (or other suitable measurement factor as recommended by the manufacturer) versus the pitch angle. Draw a smooth line through the data points. Plot also the data values for each traverse point. Determine the differences between the measured data values and the angle from the calibration curve at the same pressure ratio. The difference at each comparison must be within 2° for angles between and 40° and within 3°for angles between 40 and 60°. Environmental Protection Agency, EPA Pt. 60, App. A, Meth. 1A 2.5.6.4 Yaw Angle Calibration. Mark the three-dimensional probe to allow the determination of the yaw position of the probe. This is usually a line extending the length of the probe and aligned with the impact opening. To determine the accuracy of measurements of the yaw angle, only the zero or null position need be calilbrated as follows. Place the directional probe in the test section, and rotate the probe until the zero position is found. With a protractor or other angle measuring device, measure the angle Indicated by the yaw angle indicator on the three-dimensional probe. This should be within 2°of 0°. Repeat this measurement for any other points along the length of the pitot where yaw angle measurements could be read in order to account for variations in the pitot markings used to indicate pitot head positions. 3. Bibliography 1. Determining Dust Concentration in a Gas Stream, ASME. Performance Test Code No. 27. New York, 1957. 2. Devorkin, Howard. et al. Air Pollution Source Testing Manual. Air Pollution Control District. Los Angeles, CA November 1963. 3. Methods for Determination of Velocity, Volume, Dust and Mist Content of Gases. Western Precipitation Division of Joy Manufacturing Co. Los Angeles, CA. Bulletin WP- 50. 1968. 4. Standard Method for Sampling Stacks for Particulate Matter. In: 1971 Book of ASTM Standards, Part 23. ASTM Designation D-2928-71. Philadelphia, PA 1971. 5. Hanson, H.A., et al. Particulate Sampling Strategies for Large Power Plants Including Nonuniform Flow. USEPA, ORD, ESRL, Research Triangle Park, NC. EPA-600/ 2-76-170, June 1976. 6. Entropy Environmentalists. Inc. Determination of the Optimum Number of Sampling Points: An Analysis of Method 1 Crlterla. Environmental Protection Agency, Research Triangle Park, NC. EPA Contract No. 68-01-3172, Task 7. 7. Hanson, H.A., R.J. Davini, J.K. Morgan, and A.A. Iversen. Particulate Sampling Strategies for Large Power Plants Including Nonuniform Flow. U.S. Environmental Protection Agency. Research Triangle Park, NC. Publication No. EPA-600/2-76-170. June 1976. 350 p. 8. Brooks, E.F.. and R.L. Williams. Flow and Gas Sampling Manual. U.S. Environmental Protection Agency. Research Triangle Park, NC. Publication No. EPA-600/2- 76-203. July 1976. 93 p. 9. Entropy Environmentalists, Inc. Traverse Point Study. EPA Contract No. 68-02- 3172. June 1977. 19 p. 10. Brown. J. and K. Yu. Test Report: Particulate Sampling Strategy in Circular Ducts. Emission Measurement Branch, Emission Standards and Engineering Division. U.S. Environmental Protection Agency, Research Triangle Park, NC. 27711. July 31, 1980. 12 p. 11. Hawksley, P.G.W., S. Badzioch, and J.H. Blackett. Measurement of Solids in Flue Gases. Leatherhead, England, The British Coal Utilisation Research Association. 1961. p. 129-133. 12. Knapp, K.T. The Number of Sampling Points Needed for Representative Source Sampling. In: Proceedings of the Fourth National Conference on Energy and the Environment. Theodore, L., et al. (ed.). Dayton, Dayton Section of the American Institute of Chemical Engineers. October 3-7, 1976. p. 563- 568. 13. Smith, W.S. and D.J. Grove. A Proposed Extension of EPA Method 1 Criteria. "Pollution Engineering." XV (8):36-37. August 1983. 14. Gerhart, P.M. and M.J. Dorsey. Investigation of Field Test Procedures for Large Fans. University of Akron. Akron, OH. (EPRI Contract CS-1651). Final Report (RP- 1649-5) December 1980. 15. Smith, W.S. and D.J. Grove. A New Look at Isokinetic Sampling-Theory and Applications. "Source Evaluation Society Newsletter." VIII (3):19-24. August 1983. METHOD 1A-SAMPLE AND VELOCITY TRA- VERSES FOR STATIONARY SOURCES WITH SMALL STACKS OR DUCTS 1. Applicability and Principle 1.1 The applicability and principle of this method are identical to Method 1. except this method's applicability is limited to stacks or ducts less than about 0.30 meter (12 in.) in diameter or 0.071 m 2 (113 in.2) in crosssectional area, but equal to or greater than about 0.10 meter (4 in.) in diameter or 0.0081 m2 (12.57 in.2) in cross-sectional area. 1.2 In these small diameter stacks or ducts, the conventional Method 5 stack assembly (consisting of a Type S pitot tube attached to a sampling probe. equipped with a nozzle and thermocouple) blocks a significant portion of the cross section of the duct and causes inaccurate measurements. Therefore, for particulate matter (PM) sampling in small stacks or ducts, the gas velocity is measured using a standard pitot tube downstream of the actual emission sampling site. The straight run of duct between the PM sampling and velocity measurement sites allows the flow profile, temporarily disturbed by the presence of the sampling probe, to redevelop and stabilize. 1.3 The cross-sectional layout and location of traverse points and the verification of the absence of cyclonic flow are the same as in Method 1. Sections 2.3 and 2.4, respectively. Differences from Method 1, except as noted. are given below. METHOD 3 40 CFR PART 60 APPENDIX A ER14MY99.044 METHOD 3-GAS ANALYSIS FOR THE DETERMINATION OF DRY MOLECULAR WEIGHT 1. APPLICABILITY AND PRINCIPLE 1.1 Applicability. 1.1.1 This method is applicable for determining carbon dioxide (CO₂ ) and oxygen (O₂) concentrations and dry molecular weight of a sample from a gas stream of a fossil-fuel combustion process. The method may also be applicable to other processes where it has been determined that compounds other than CO2. O₂, carbon monoxide (CO), and nitrogen (N₂) are not present in concentrations sufficlent to affect the results. 1.1.2 Other methods, as well as modifications to the procedure described herein, are Environmental Protection Agency, EPA also applicable for some or all of the above determinations. Examples of specific methods and modifications include: (1) A multipoint sampling method using an Orsat analyzer to analyze individual grab samples obtained at each point; (2) a method using CO 2 or O₂ and stoichiometric calculations to determine dry molecular weight: and (3) assigning a value of 30.0 for dry molecular weight, in lieu of actual measurements, for processes burning natural gas, coal, or oil. These methods and modifications may be used, but are subject to the approval of the Administrator, U.S. Environmental Protection Agency (EPA). 1.1.3 Note. Mention of trade names or speciflc products does not constitute endorsements by EPA. 1.2 Principle. A gas sample is extracted from a stack by one of the following methods: (1) Single-point, grab sampling: (2) single-point, integrated sampling; or (3) multipoint. integrated sampling. The gas sample is analyzed for pecent CO 2. percent O₂, and If necessary, for percent CO. For dry molecular weight determination, either an Orsat or a Fyrite analyzer may be used for the analysis. 2. APPARATUS As an alternative to the sampling apparatus and systems described herein. other sampling systems (e.g., liquid displacement) may be used, provided such systems are capable of obtaining a representative sample and maintaining a constant sampling rate, and are, otherwise, capable of yielding acceptable results. Use of such systems is subject to the approval of the Administrator. 2.1 Grab Sampling (Figure 3-1). 2.1.1 Probe. Stainless steel or borosilicate glass tubing equipped with an in-stack or out-stack filter to remove particulate matter (a plug of glass wool is satisfactory for this purpose). Any other materials, inert to O₂, CO2, CO, and N₂ and resistant to temperature at sampling conditions, may be used for the probe. Examples of such materials are aluminum, copper, quartz glass, and Teflon. 2.1.2 Pump. A one-way squeeze bulb, or equivalent. to transport the gas sample to the analyzer. 2.2 Integrated Sampling (Figure 3-2). 2.2.1 Probe. Same as in Section 2.1.1. 2.2.2 Condenser. An air-cooled or watercooled condenser, or other condenser no greater than 250 ml that will not remove O2, CO2, CO, and N₂. to remove excess moisture which would Interfere with the operation of the pump and flowmeter. 2.2.3 Valve. A needle valve, to adjust sample gas flow rate. EC01JN92.096 2.2.4 Pump. A leaf-free, diaphragm-type pump, or equivalent. to transport sample gas to the flexible bag. Install a small surge tank between the pump and rate meter to eliminate the pulsation effect of the diaphragm pump on the rotameter. 2.2.5 Rate Meter. A rotameter, or equivalent rate meter, capable of measuring flow rate to within 2 percent of the selected flow rate. A flow rate range of 500 to 1000 cc/min is suggested. 2.2.6 Flexible Bag. Any leak-free plastic (e.g., Tedlar, Mylar, Teflon) or plastic-coated aluminum (e.g., aluminized Mylar) bag, or equivalent. having a capacity consistent with the selected flow rate and time length of the test run. A capacity in the range of 55 to 90 liters is suggested. To leak check the Environmental Protection Agency, EPA bag. connect It to a water manometer. and pressurize the bag to 5 to 10 cm H₂ o (2 to 4 in. H₂O). Allow to stand for 10 minutes. Any displacement in the water manometer indicates a leak. An alternative leak-check method is to pressurize the bag to 5 to 10 cm (2 to 4 In.) H2O and allow to stand overnight. A deflated bag indicates a leak. 2.2.7 Pressure Gauge. A water-filled U-tube manometer. or equivalent, of about 30 cm (12 in.), for the flexible bag leak check. 2.2.8 Vacuum Gauge. A mercury manometer, or equivalent. of at least 760 mm (30 in.) Hg, for the sampling train leak check. 2.3 Analysis. An Orsat or Fyrite type combustion gas analyzer. For Orsat and Fyrite analyzer maintenance and operation procedures, follow the instructions recommended by the manufacturer, unless otherwise specified herein. 3. SINGLE-POINT. GRAB SAMPLING AND ANALYTICAL PROCEDURE 3.1 The sampling point in the duct shall elther be at the centroid of the cross section or at a point no closer to the walls than 1.00 m (3.3 ft), unless otherwise specified by the Administrator. 3.2 Set up the equipment as shown in Figure 3-1, making sure all connections ahead of the analyzer are tight. If an Orsat analyzer is used, it is recommended that the analyzer be leak checked by following the procedure in