204 Technology Park Lane

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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 27526
• tel [phone] fax [phone]
• email info_at_apexinst.com
• web www.apexinst.com

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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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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(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 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
KINETIC MOTION
ISO EQUAL

Isokinetic Sampling is an equal or uniform
sampling of particles and gases in motion within
the air stream.
Isokinetic Sampling
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Isokinetic Sampling
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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
17 Particulate Emissions (in stack
filter) Method 23 Dioxin / Furans Method
26A Hydrogen Chloride Method 29 Multi
Metals Method 201A Determination of PM10
Particulate Method 0010 Semi Volatile Compounds
Isokinetic Sampling
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Method 1
Sample and Velocity Traverses from Stationary
Sources
Apex Instruments Inc.
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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.
Method 1
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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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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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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) 0.32 ( O2) 0.28 ( CO
N2)
Method 3
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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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Method 5
Determination of Particulate Emissions from
Stationary Sources
Apex Instruments Inc.
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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 120 14oC.
The particulate mass is determined
gravimetrically after removal of uncombined water.
Method 5
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Method 5 System
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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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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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
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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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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(cont.)
Particulate Train Operation
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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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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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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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
Method 17
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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