1. 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.

2. 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..

3. 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

4. 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

5. 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

6. “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

7. 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

8. 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

9. 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

10. Method 1 Apex Instruments Inc. Sample and Velocity Traverses
from Stationary Sources
Apex Instruments Inc.

11. 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

12. 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

13. 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

14. Method 1

15. 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

16. Location of Traverse Points in Circular Stacks
Method 1

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

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

19. 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

20. Pressure Components in Gas Streams
a) Stagnation Pressure
b) Static Pressure
c) Velocity Pressure, (DP)
Method 2

21. 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

22. 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

23. 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.

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

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

26. Dry molecular weight (Md) is calculated from the gas analysis results
Md = (0.44 % CO2) (% O2) (% CO + % N2)
Method 3

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

28. 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

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

30. 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

31. 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

32. 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

33. 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

34. 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

35. 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

36. Tools available for solving isokinetic rate equations include:
Slide Rule
Computer Program
Calculator
Method 5

37. 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

38. Method 5 Components
Method 5

39. 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

40. 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

41. 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

42. 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

43. Alternative Sampling Trains for Particulates
Flexible Method 5
Compact Method 5
Method 17
Method 201A
Apex Instruments Inc.

44. Flexible Method 5 Uses flexible line between filter unit and condenser
* Heated line may be required for some methods
Alternative Sampling Trains for Particulates

45. 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

46. 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

47. Schematic of the EPA Method 17 Flex Sampling Train

48. Method 201A PM10 Sampling Train Constant Sampling Rate Procedure (CSR)
Alternative Sampling Trains for Particulates

49. 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