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**Fuquay Varina, North Carolina 27526**

An Introduction to Isokinetic Source Sampling presented by: Apex Instruments Inc. Manufacturer of Quality Sampling Equipment “Since 1988” 204 Technology Park Lane Fuquay Varina, North Carolina tel: fax: web: Apex Instruments Inc.

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Apex Instruments Inc. designs, manufactures, and markets equipment used for the collection of air samples from smoke stacks, chimneys, industrial ducts, and other process air streams. Apex Instruments Inc..

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**Isokinetic Sampling Emission Data can be used: Government**

To provide data for determining appropriate emission limits. To provide data for determining compliance. To provide data for health risk assessments. To provide data for dispersion modeling. Isokinetic Sampling

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**Isokinetic Sampling Emission Data can be used: Industry**

(continued) Emission Data can be used: Industry To evaluate air pollution control equipment. To provide information for design of new process and control equipment. To provide information on process operations. Isokinetic Sampling

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**Isokinetic Sampling Isokinetic Measurement of Source Emissions:**

Particulate emissions from a source are sampled isokinetically using a US EPA Method 5 sampling train. The collected sample is analyzed to determine the pollutant concentrations. Isokinetic Sampling

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**“ISOKINETIC” Isokinetic Sampling ISO = EQUAL + KINETIC = MOTION**

Isokinetic Sampling is an equal or uniform sampling of particles and gases in motion within the air stream. Isokinetic Sampling

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**Basic Terminology Isokinetic Sampling Pmrs = Cs Qs CONCENTRATION (Cs)**

Quantity of pollutant per volume of effluent gas grams / cubic meter STACK GAS FLOW RATE (Qs) Volume of effluent gas per length of time cubic meters / hour POLLUTANT MASS RATE EQUATION (Pmrs) Volume of pollutant gas per length of time grams / hour Isokinetic Sampling

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**Isokinetic Sampling Isokinetic Sampling is the application of five**

sampling methods developed by the USEPA plus the applicable method: Method 1 - Sample and Velocity Traverses from Stationary Sources Method 2 - Determination of Stack Gas Velocity and Volumetric Flow Rate Method 3 - Gas Analysis for Carbon Dioxide, Oxygen, Excess Air, and Dry Molecular Weight Method 4 - Determination of Moisture Content in Stack Gases Method 5 - Determination of Particulate Emissions from Stationary Sources Isokinetic Sampling

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**Partial Listing of US EPA Isokinetic Sampling Methods:**

Method 8 Sulfuric Acid Mist & SO2 Method 12 Inorganic Lead Method 13A Fluorides Method Particulate Emissions (in stack filter) Method 23 Dioxin / Furans Method 26A Hydrogen Chloride Method 29 Multi Metals Method 201A Determination of PM10 Particulate Method Semi Volatile Compounds Isokinetic Sampling

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**Method 1 Apex Instruments Inc. Sample and Velocity Traverses**

from Stationary Sources Apex Instruments Inc.

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**Method 1 Method 1 is used to:**

1. Select an appropriate sampling location 2. Determine the required number of particulate sampling points 3. Calculate the location of the sampling points within the duct. Method 1

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Ideal site should be at least 8 duct diameters downstream & 2 duct diameters upstream from any flow disturbance. Minimum distances are 2 duct diameters downstream and ½ duct diameters upstream from any flow disturbance. Method 1

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The number of sample points is dependent on the distance from any flow disturbance (measured in duct diameter). The following table is used for determining the required number of sampling points. Method 1

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Method 1

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**The cross section is divided into the desired number of equal areas.**

Isokinetic sampling is conducted at discrete points in the cross-section of the duct . The following table is used for determining the location of sampling points. Method 1

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**Location of Traverse Points in Circular Stacks**

Method 1

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**The probe is marked to correspond to the appropriate sampling point using the table from Method 1.**

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**and Volumetric Flow Rate**

Method 2 Determination of Stack Gas Velocity and Volumetric Flow Rate Apex Instruments Inc.

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Velocity Traverses are conducted by measuring the stack gas velocity pressure (Dp) and stack temperature at each of the sample points determined by the Method 1 calculations. Method 2 is used to: Conduct a pre-test velocity traverse Determine the effluent gas velocity Method 2

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**Pressure Components in Gas Streams**

a) Stagnation Pressure b) Static Pressure c) Velocity Pressure, (DP) Method 2

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**Method 2 Type S (Stausscheibe) Pitot Tube**

Most commonly used in conjunction with Method 5 because of its: Compact size - fits in small ports Durability in design Plugging resistance in heavy particulate Sensitivity at low velocities Method 2

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Velocity measurements are conducted simultaneously during the sample period for the setting of the isokinetic sampling rate. Volumetric flows are adjusted for temperature, pressure, and gas molecular weight. Method 2

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**for Carbon Dioxide, Oxygen, Excess Air, and Dry Molecular Weight**

Method 3 Stack Gas Analysis for Carbon Dioxide, Oxygen, Excess Air, and Dry Molecular Weight Apex Instruments Inc.

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Method 3 is applicable for determining Dry Molecular Weight and excess air correction factors from fossil fuel combustion sources. Method 3 Method 3

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Orsat Analyzer A gas sample is collected in a tedlar bag and analyzed for CO2, O2 and sometimes CO. Method 3

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**Dry molecular weight (Md) is calculated from the gas analysis results**

Md = (0.44 % CO2) (% O2) (% CO + % N2) Method 3

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**Determination of Moisture**

Method 4 Determination of Moisture Content in Stack Gases Apex Instruments Inc.

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**Moisture Content Procedure**

The water vapor is condensed in the impingers. The net gain is measured and the percent moisture is calculated. * Approximation methods are used to estimate percent moisture for setting isokinetic sampling rates. Method 4

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**Determination of Particulate Emissions from Stationary Sources**

Method 5 Determination of Particulate Emissions from Stationary Sources Apex Instruments Inc.

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**Method 5 Method 5 Principle**

Particulate matter is withdrawn isokinetically from the source and collected on a glass fiber filter maintained at a temperature in the range of oC. The particulate mass is determined gravimetrically after removal of uncombined water. Method 5

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**Method 5 System Method 5 Components: Probe Assembly**

Heated Filter Compartment (Hot Box) Condenser Unit (Cold Box) Umbilical Cable Metering Console with Pump Method 5

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To obtain a representative sample of particulate matter from an air stream the velocity at the nozzle opening should be equal to the velocity of the approaching gas stream. Isokinetic Sampling

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100% Isokinetic 100% isokinetic means that the velocity at the tip of the nozzle is equal to stack velocity. The true particulate concentration will therefore be obtained. Method 5

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**Method 5 Under Isokinetic**

When the nozzle velocity is less than the stack velocity the results will be biased high due to the inertia of the large particles. Method 5

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**Method 5 Over Isokinetic**

When the nozzle velocity is greater than the stack velocity the results will biased low since the larger particles break through the air stream and bypass the nozzle. Method 5

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**Tools available for solving isokinetic rate equations include:**

Slide Rule Computer Program Calculator Method 5

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**PRETEST PREPARATIONS Method 5**

A tared filter is placed in the filter holder A known amount of water and silica gel is placed in the impingers A preliminary velocity determination is made to select the proper size nozzle Sampling train is leak checked Method 5

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Method 5 Components Method 5

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**Method 5 Particulate Train Operation**

A compliance test will require at least three Method 5 sample runs. Each run must be for a minimum of 1 hour and 30 scf or other specified minimum time and sample volume. Sample train placed at first point and sample pump is started Method 5

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**Method 5 Particulate Train Operation (cont.)**

Sample rate is adjusted to isokinetic after moving to each new sample point and any time the velocity pressure reading changes by more than 20%. The isokinetic rate setting is determined with a calculator or nomograph and established with a flowrate meter called an orifice meter. The sampling train is only shut down to move from port to port and at the end of the sample run. Method 5

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**Method 5 Post Test Operation**

Upon completion of testing the sampling train must pass a leak test. The sample train is removed to a cleanup area that is free of dust and wind. The filter is removed from the container and placed in a sample container. Sample is removed from the sample exposed portions of the nozzle, probe liner and filter holder with acetone and placed in a sample container. Method 5

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Analysis Filter is desiccated for a minimum of 24 hours and then weighed to a constant weight. Acetone sample rinse and an acetone blank are evaporated to dryness and weighed to a constant weight. The sample residue is weighed to a constant weight and the residue weight of the acetone is subtracted from the evaporated sample to yield the weight of the sample. Sum of the weight of the sample on the filter and in the acetone rinse is used to calculate the particulate emissions. Method 5

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**Alternative Sampling Trains for Particulates**

Flexible Method 5 Compact Method 5 Method 17 Method 201A Apex Instruments Inc.

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**Flexible Method 5 Uses flexible line between filter unit and condenser**

* Heated line may be required for some methods Alternative Sampling Trains for Particulates

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**Alternative Sampling Trains for Particulates**

Compact Method 5 Includes: Heated Stainless Steel Filter Unit Stainless Steel Liner Flexible Sample Line extension Cut-back Umbilical Cable Alternative Sampling Trains for Particulates

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**Alternative Sampling Trains for Particulates**

Method 17 In-stack Filter Applicability In sources where particulate matter concentration is independent of temperature. Alternative Sampling Trains for Particulates

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**Schematic of the EPA Method 17 Flex Sampling Train**

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**Method 201A PM10 Sampling Train Constant Sampling Rate Procedure (CSR)**

Alternative Sampling Trains for Particulates

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The PM10 Cyclone is built to EPA specifications for Method 201A testing and is designed for in-stack measurement of particulate matter equal to or less than 10 microns. The cyclone and in-stack filter assembly adapts easily to Method 5 probe assembly. PM10 Kit Method 201A

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