Series-1 -100-7/82
EVALUATION OF STATIONARY
SOURCE PERFORMANCE TESTS
Emission Testing Concepts
and Special Topics
A
U S ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF AIR, NOISE AND RADIATION
STATIONARY SOURCE COMPLIANCE DIVISION
WASHINGTON DC 20460
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DRAFT
EVALUATION OF STATIONARY SOURCE
PERFORMANCE TESTS
Emission Testing Concepts and
Special Problems
Prepared by
PEDCo Environmental, Inc.
505 South Duke Street, Suite 503
Durham, North Carolina 27701
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF AIR, NOISE AND RADIATION
STATIONARY SOURCE COMPLIANCE DIVISION
WASHINGTON, D.C. 20460
July 1982
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INTENDED PURPOSE
This is not an official policy and standards document. The opinions,
findings, and conclusions are those of the authors and not necessarily those
of the Environmental Protection Agency. Every attempt has been made to repre-
sent the present state of the art as well as subject areas still under eval-
uation. Any mention of products or organizations does not constitute endorse-
ment by the United States Environmental Protection Agency.
This document is issued by the Stationary Source Compliance Division,
Office of Air Quality Planning and Standards, USEPA. It is for use in work-
shops presented by Agency staff and others receiving contractual or grant
support from the USEPA. It is part of a series of instructional manuals
addressing compliance testing procedures.
Governmental air pollution control agencies establishing training pro-
grams may receive single copies of this document, free of charge, from the
Stationary Source Compliance Division Workshop Coordinator, USEPA, MD-7,
Research Triangle Park, NC 27711. Since the document is specially designed
to be used in conjunction with other training materials and will be updated
and revised as needed periodically, it is not issued as an EPA publication
nor copies maintained for public distribution.
iii
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CONTENTS
Page
Section A. Introduction to Source Sampling (Lecture 101) A-l
1. Basic terminology and nomenclature A-3
2. Slides A-25
Section B. Method 1 (Lecture 102) B-l
1. Method 1—Sample and velocity traverses for sta-
tionary sources B-3
2. Slides B-15
Section C. Method 2 (Lecture 103) C-l
1. Method 2—Determination of stack gas velocity and
volumetric flow rate C-3
2. Slides C-35,
Section D. Method 3 (Lecture 104) D-l
1. Method 3—Gas analysis for carbon dioxide, oxy-
gen, excess air, and dry molecular weight D-3
2. Slides D-19
Section E. Method 4 (Lecture 105) E-l
1. Method 4—Determination of moisture content in
stack gases E-3
2. Slides E-21
Section F. Method 5 (Lecture 106) • F-l
1. Method 5—Determination of particulate emissions
from stationary sources F-3
2. Slides F-43
Section G. Method 6 (Lecture 107) G-l
1. Method 6—Determination of sulfur dioxide emis-
sions from stationary sources G-3
2. Slides G-19
Section H. Method 7 (Lecture 108) H-l
1. Method 7—Determination of nitrogen oxide emis-
sions from stationary sources H-3
2. Slides H-19
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CONTENTS (continued)
Page
- •- jr
Section I. Method 8 (Lecture 109) 1-1
1. Method 8—Determination of sulfuric acid mist and
sulfur dioxide emissions from stationary sources 1-3
2. Slides 1-21
Section J. Highlights of EPA Methods 1-5 (Lecture 150) j-l
Section K. Summary of Equations (Lecture 151) K-l
1. Source sampling calculations K-3
2. Slides K-19
Section L. Misalignment of Pitot Tube (Lecture 152) L-!
1. Pitot tube errors due to misalignment and non-
streamlined flow L-3
2. Slides L-7
Section M. Isokinetic Sampling and Biases from Noniso-
kinetic Sampling (Lecture 153) M-l
1. A method of interpreting stack sampling data M-3
2. Slides M-13
Section N. Precision and Accuracy of Test Methods N-l
(Lecture 154)
1. Information to support data quality acceptance
for performance audits and routine monitoring N-3
2. Error analyses N-8
3. Slides N-13
Section 0. Significance of Error for Source Test
Observers (Lecture 155) O-l
1. Use of significance of error for source test
observer's decisions O-3
2. Slides O-ll
Section P. Stack Sampling Nomographs (Lecture 156) P-l
1. Stack sampling nomographs for field validation P-3
2. Slides P-27
vi
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SECTION A. INTRODUCTION TO SOURCE SAMPLING
Subject Page
1. Basic terrm'nology and nomenclature (taken frofh the APTI Course
450 manual) A-3
2. Slides A-25
A-l
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Basic Terminology and Nomenclature
There are three terms which are used to describe what exists in a stack:
1. Concentration - The quantity of a pollutant per quantity of effluent
gas. An example of this is:
grains (a weight unit)/cubic foot (a volume unit)
2. Stack gas flow rate - the quantity of effluent gas passing up the stack
per length of time. An example of this is:
cubic feet (a volume unit)/hour (a time unit)
3. Pollutant mass rate - The quantity of pollutant passing up the stack
per length of time. An example of this is:
pounds (a weight unit)/hour (a time unit)
These three terms are related to each other by the .equation:
where pmr = average pollutant mass emissions rate
c~ = average stack concentration
Q_ = average volumetric flow rate from the stack
The objective is to determine pmr , so the general approach is to determine
*)
c". and Q_ (see Stack Sampling Flow Diagram). c_ is determined through sampling
o o o
train design. Q" is given by the equatipn
Qs - Vs As ^
where v"s = average stack velocity
AS = cross-section area of the stack
The cross-section area Ag is easily determined. The task of determin.ing
the average stack velocity, V , is discussed in a following section.
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Stack Sampling Fiow Diagram
The overall objective of stack sampling is the determination of the average
pollution mass emission rate (pmrs) and can be summarized by the flow diagram
below.
Q = A v
s s s
prar = c 0
r s s x
M
Composition
Sampling Train Design
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i
01
HEATED AREA v F|LTER HOLDER
THERMOMETER
CHECK
VALVE
.REVERSE-TYPE
PITOT TUBE
PITOT MANOMETER L
ICE BATH
BY-PASS VALVE
VACUUM
GAUGE
MAIN VALVE
VACUUM
LINE
Paniculate sampling train.
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The Source Test
A source sampling experiment provides data on source emissions parameters. The
isokinetic source test extracts a representative gas sample from a gas stream.
Although often used only to determine compliance with emissions regulations, the
test data can also provide information useful in evaluating control equipment effi-
ciency or design, process economics, or process control effectiveness. Valid source
sampling experiments, therefore, yield valuable information to both the industrial
and environmental engineer.
The source test is an original scientific experiment and should be organized and
executed with the same care taken in performing any analytical experiment. This
requires that objectives be decided before starting the experiment and that the pro-
cedures and equipment be designed to aid in reaching those objectives. The quan-
titative or qualitative analysis of the source sample should be incorporated as an in-
tegral part of the source test. After all work is done, the results should be evaluated
to determine whether objectives have been accomplished. This section contains flow
charts and descriptions to assist in the design, planning, and performance of the
source test described.
Source Test Objectives
The essential first step in all experiments is the statement of objectives. The source
test measures a variety of stack gas variables which are used in evaluating several
characteristics of the emissions source. The source experiment should be developed
with techniques and equipment specifically designed to give complete, valid data
relating to these objectives. Approaching the experiment in this manner increases
the possibilities of a representative sampling of the source parameters to be
evaluated.
Experiment Design
A well designed experiment incorporates sampling equipment, techniques, and
analysis into an integrated procedure to meet test objectives. The source sampling
experiment must be based on a sampling technique that can collect the data re-
quired. The sampling equipment is then designed to facilitate the sampling pro-
cedure. The analysis of the sample taken must be an integral factor in the
sampling techniques and equipment design. This approach of achieving test objec-
tives provides the best possible source test program.
Designing a source test experiment requires a knowledge of sampling procedures
and industrial processes, a thoroughly researched sampling experiment, and a good
basic understanding of the process operation to be tested. This knowledge assists in
determining the types of pollutants emitted and test procedures and analysis that
A-6
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will achieve valid, reliable test results. A literature search of the sampling problem
can yield information that may help improve test results or make testing much
easier.
Final Test Protocol
The final test protocol clearly defines all aspects of the test program, and incor-
porates the work done in research, experiment design, and the presurvey. All
aspects of this test, from objectives through analysis of the sample and results of the
sampling, should be organized into a unified program. This program is then ex-
plained to industrial or regulatory personnel involved. The protocol for the entire
test procedure should be understood and agreed upon prior to the start of the test.
A well organized test protocol saves time and prevents confusion as the work
progresses.
Test Equipment Preparations
The test equipment must be assembled and checked in advance; it should be
calibrated following procedures recommended in the Code of Federal Regulations
and this manual. The entire sampling system should be assembled as intended for
use during the sampling experiment. This assures proper operation of all the com-
ponents and points out possible problems that may need special attention during
the test. This procedure will assist in making preparations and planning for spare
parts. The equipment should then be carefully packed for shipment to the
sampling site.
The proper preparation of sampling train reagents is an important part of get-
ting ready for the sampling experiment. The Method 5 sampling train requires well
identified, precut, glass mat filters that have been desiccated to a constant weight.
These tare weights must be recorded to ensure against errors. Each filter should be
inspected for pinholes that could allow particles to pass through. The acetone (or
other reagent) used to clean sampling equipment must be a low residue, high
purity solvent stored in glass containers. Silica gel desiccant should be dried at 250 °
to 300°F for 2 hours, then stored in air-tight containers; be sure the indicator has
not decomposed (turned black). It is a good procedure, and relatively inexpensive,
to use glass-distilled, dionized water in the impingers. Any other needed reagents
should be carefully prepared. All pertinent data on the reagents, tare weights, and
volumes should be recorded and filed in the laboratory with duplicates for the
sampling team leader.
Testing at the Source
The first step in performing the source test is establishing communication among
all parties involved in the test program. The source sampling test team should
notify the plant and regulatory agency of their arrival. All aspects of the plant
operation and sampling experiment should be reviewed and understood by those
A-7
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Figure 5-1. Planning and performing a stack test.
EACH STACK TEST
SHOULD BE CONSIDERED
AN ORIGINAL SCIENTIFIC
EXPERIMENT
CALIBRATE EQUIPMENT
•DGM
•Determine console AH®
•Noii la
•Thermometers and
thermocouples
•Pressure gages
•Orsat
•Pitoc tube and probe
•Nomographs
DETERMINE NECESSITY OF A SOURCE TEST
•Decide on data required
•Determine that source text will give this data
•Analyze cost
ARRIVAL AT SITE
•Notify plant and
regulatory agency
personnel
•Review test plan with all
concerned
•Check weather forecasts
•Confirm process ope.-ation
parameters in control room
±
STATE SOURCE TEST OBJECTIVES
•Process evaluation
•Process design data
•Regulatory compliance
DESIGN EXPERIMENT
•Develop sampling approach
•Select equipment to meet test objectives
•Select analytical method
•Evaluate possible errors or biases and correct
sampling approach
•Determine manpower needed for test
•Determine time required for test with margin for
breakdowns
•Thoroughly evaluate entire experiment
with regard to applicable State and Federal
guidelines
PRE-SURVEY SAMPLING SITE
•Locate hotels and restaurants in area
•Contact plant personnel
•Inform plant personnel of testing objectives and
requirements tor completion
•Note shift changes
•Determine accessibility of sampling site
•Evaluate safety
•Determine pan locations and application to
Method! 1 and 2 (12/23/71 Federal Register)
•Locate electrical power supply to site
•Locale rcstiooms and food at plane
•Drawings, photographs, or blueprints of sampling site
•Evaluate applicability of sampling approach from
experiment design
•Note any special equipment needed
FINALIZE TEST PLANS
_L
•Incorporate prcrarrey into experiment design
•Submit experiment design for ap-
proval by Industry and Regulatory Agency
•Set test dates and duration
PREPARE EQUIPMENT FOR TEST
•Assemble and confirm operation
•Prepare for shipping
•Include spare parts and reserve equipment
JL
CONFIRM TRAVEL AND SAMPLE TEAM ACCOM-
MODATIONS AT SITE
CONFIRM TEST DATE AND PROCESS OPERATION
•Final step before travel arriving at site
SAMPLING FOR PARTICULATE EMISSIONS
•Carry equipment to sampling site
•Locate electrical connections
•Assemble equipment
PRELIMINARY CAS VELOCITY TRAVERSE
•Attach thermocouple or thermometer to pilot
probe assembly
•Calculate sample points from guidelines outlined in
Method 1 and 2 of Federal Register
•Mark pilot probe
•Traverse duct for velocity profile
•Record -Ip's and temperature
•Record duct static pressure
T
RESEARCH LITERATURE •
•Basic process operation
•Type of pollutant emitted
from process
•Physical state at source
conditions
•Probable points of emission
from process
•Read sampling reports
from other processes
sampled:
1. Problems to expect
2. Estimates of variables
a. H;>O vapor
b. Temperature at
source
•Study analytical pro-
cedures used for
processing test samples
PREPARE FILTERS AND
REAGENTS
•Mark filters with insoluble
ink
•Desiccate tu const-nt
weight
•Record weights in per-
manent laboratory file
•Copy file for on site record
•Measure deionized distilled
HgO for impingers
•Weigh silica gel
•Clean sample storage
containers
DETERMINE APPROX-
IMATE MOLECULAR
WEIGHT OF STACK CAS
USING FYRITE AND
NOMOGRAPHS
APPROXIMATE HoO
VAPOR CONTENTOF
STACK GAS
A-8
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involved. The proper plant operating parameters and sampling experiment pro-
cedures should be recorded in a test log for future reference. The sampling team is
then ready to proceed to the sampling site.
The flow diagram outlines the procedures for performing the stack test. The
items given are for a basic Method 5 paniculate sample. Each item is explained in
various sections of this manual. The laboratory training sessions given in Course
450 help to organize the Method 5 test system.
The flow diagram should be of assistance to those having completed the 450
course curriculum and can also serve as a useful guide to anyone performing a
stack test.
METHODS FOR SETTING THE ISOKINETIC FLOW RATE
IN THE METHOD 5 SAMPLING TRAIN
The commercially available nomograph is often used for the solution of the
isokinetic rate equation. These nomographs have based the solution of the
isokinetic equation upon the assumptions that the pitot tube coefficient will be
0.85, the stack gas dry molecular weight will be 29.0 Ib/lb-mole and will only vary
with a change in stack gas moisture content in addition to relying on the use of a
drying tube in the train. The nomograph also assumes that changes in other equa-
tion variables will be insignificant. Many purchasers are unaware of these assump-
tions or manufacturer construction errors and use the device without calibrating it
or verifying its accuracy. Procedures are presented here to ascertain the precision of
nomograph construction and its accuracy. The basic equations employed in con-
structing a nomograph are given and a calibration form is provided.
The equation for derivation of the isokinetic rate is given
below:
f s n * Md Tm Pr~\
(Eq.5-1) AH- 846.72 Dn4 AH@ Cp2(\~Bws)2 M - p A/»
L Ms 1s ^m J
where Cp = pitot tube coefficient
Dn = nozzle diameter (in.)
A//=pressure difference of orifice meter (in. fyO)
AH@ = orifice meter coefficient, AH for 0. 75 cfm at
STP=0.9244/Km2 (in. H2O)
Ms = apparent stack gas molecular weight
^Mdfl-BaJ + lSBu, (lb/lb.moie)
Md = dry gas molecular weight (29) for dry air
. (Ib/lb-mole)
Ps = absolute stack pressure (in. Hg)
pm = meter absolute pressure (in. Hg)
Ap = pressure difference of pitot tube (in. H.2O)
Tm = absolute meter temperature = °R= °F+ 460°
isokinetic AH = KAp
K = Reduced terms in the isokinetic equation.
A-9
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RECORD ALL INFORMA-
TION ON DATA SHEETS
•Sample case number
•Meter console number
•Probe length
•Barometric pressure
•Nozzle diameter
•C factor-
•Assumed H2O
•Team supervisor
•Observers present
•Train leak test rate
•General comments
•Initial DGM dial readings
TAKE INTEGRATED
SAMPLE OF STACK GAS
FOR ORSAT ANALYSIS (OR
PERFORM MULTIPLE
FYRJTE READINGS
ACROSS DUCT)
_L
ANALYZE STACK GAS FOR
CONSTITUENT GASES
•Determine molecular
weight
•CO, and O»
concentration for F-factor
calculations
L
PREPARE OTHER TRAIN;
FOR REMAINING
SAMPLING
REPACK EQUIPMENT
AFTER SAMPLING IS
COMPLETED
i
USE NOMOGRAPH OR CALCULATOR TO SIZE
NOZZLE AND DETERMINE C FACTOR
•Adjust for molecular weight and pilot tube C
•Set K pivot point on nomograph
LEAK TEST COMPLETELY ASSEMBLED
SAMPLING TRAIN @15" Hs VACUUM AND
MAXIMUM LEAK RATE OF 0.02 CFM
I NOTIFY ALL CONCERNED THAT TEST IS ABOUT
TO START
I CONFIRM PROCESS OPERATING PARAMETERS I
• ^
START SOURCE TEST
•Record start time - military base
•Record gat velocity
•Determine AH desired from nomograph
•Stan pump and set orifice meter
differential manometer to desired AH
•Record
1. Sample point
2. Time from zero
3. DGM dial reading
4. Desired AH
5. Actual AH
6. All temperatures DGM, stack, sample case
•Maintain isokinetic AH at all times
•Repeat for all points on traverse
\ MONITOR PROCESS RATE |
'
TAKE MATERIAL
SAMPLES IF NECESSARY
TAKE CONTROL ROOM
DATA
AT CONCLUSION OF TEST RECORD
•Stop time - 24 hour clock
•Final DGM
•Any pertinent observations on sample
LEAK TEST SAMPLE TRAIN
•Test at highest vacuum (in. Hg) achieved during test
•Leak rate should not exceed 0.02 CFM
•Note location of any leak if possible
REPEAT PRECEDING STEPS FOR THREE
PARTICULATE SAMPLES
SAMPLE CLEAN-UP AND RECOVERY
•dean samples in laboratory or other clean area
removed from site and protected from the outdoors
•Note sample condition
•Store samples in quality assurance containers
•Mark am1 label .ill samples
•Pack carefully for shipping if analysis is not done on
site
ANALYZE SAMPLES
•Follow Federal Register or State guidelines
•Document procedures and any variations employed
•Prepare analytical Report Data
CALCULATE
•Moisture content of stack gas
•Molecular weight of gas
•Volumes sampled at standard conditions
•Concentration/standard volume
•Control device efficiency
•Volumetric flow rate of stack gas
•Calculate pollutant mass rate
WRITE REPORT
•Prepare as possible legal document
•Summarize results
•Illustrate calculations
•Give calculated results
•Include all raw data (proce* dr test)
•Attach descriptions of testing and analytical methods
•Signatures of analytical and lest personnel
SEND REPORT WITHIN MAXIMUM TIME
TO INTERESTED PARTIES
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_L
CALIBRATE EQUIPMENT
•Noules
•DGM
•Orifice meter
•Mncr console
•Pilot tubes
•Nomograph
Figure 5-2. Source cest outline.
[ASSEMBLE SAMPLING TRAIN
X
LEAK TEST
•Pilot lino
•Meter console
•Sampling train @ 15" Hg.
SET UP NOMOGRAPH OR CALCULATOR
JL
•Mark dry and desiccate
filters to constant weight
•Assemble in filter* and ical
until ready to use
ESTIMATE COz
CONCENTRATION USING
FYRITE
CALCULATE SAMPLE POINT USING
1
DO PRELIMINARY TEMPERATURE
VELOCITY TRAVERSE
METHOD 1
AND
I . -
1
ESTIMATE H?
USING WET B
BULB
1
PREPARE TO TAKE
INTEGRATED SAMPLE OF
FLUE GAS DURING EN-
TIRE DURATION OF TEST
I ANALYZE USING ORSAT
FILL OUT DATA SHEET
•Date *DGM Reading
•Time 'Test time at each point
MONITOR AT EACH TEST POINT
•DGM—On time
•Ap
•Appropriate AH
•Slack temperature
•Sample case temperature
•Impinger temperature
STOP TEST AND RECORD
•Final DGM
•Slop time
•Note* on sampling and appearance of sample
MONITOR BOILER
OPERATION
RECORD FUEL FEED
RATE AND PRODUCTION
RATE
LEAK TEST AT HIGHEST VACUUM REACHED
DURING TEST
SAMPLE CLEAN-UP
•Probe & nozzle
•Filter
•H2O
•Silica Gel
CALCULATE
•Moisture content of gas
•Molecular weight of gas (dry Ic wet)
•Average gas velocity
•% isokinelic
•Pollutant mass rate
(concentration and ratio of areas)
WRITE REPORT
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The Method 5 sampling train is intended to operate at a sampling rate of
0.75 cfm of dry air at 68°F and 29.92 in. Hg. The orifice meter pressure differen-
tial that would produce such a sampling rate through the orifice is designated
An additional equation is necessary in order to estimate the nozzle diameter that
will give a flow rate of 0.75 cfm at a reasonable pressure drop across the orifice
meter. /;
.0358
(Eq.5-2)
/
n 1 /°-
Dn=\/
j/
Tm Cp(l-Bws)
where Dn = nozzle diameter (in.)
Qjn~ volumetric flow rate through meter (ft*)
Pm = absolute pressure at meter (in. Hg)
Ps = absolute pressure at stack (in. Hg)
Tm = absolute temperature at meter (°R)
Ts = absolute temperature at stack (°R)
Cp — pitot tube calibration coefficient
Bws = water vapor in stack gas, volume fraction
Ms = molecular weight of stack gas, wet basis
(Ib/lb-mole)
i = average velocity head of stack gas (in. H2O)
Once Dn is calculated, the source tester should select the nozzle in his tool box
which has a value closest to that calculated. The actual nozzle used should be
checked with calipers, and that value of Dn is then substituted in Equation 5-1.
Most of the variables in this equation and the isokinetic AH equation are known
prior to sampling or can be closely estimated. Often the solution to the equation
can be partially calculated before the sampling with the few remaining variables
inserted and the equation quickly solved on site. The calculation of isokinetic AH
using the derived equations allows the sampler to more quickly and easily adjust
the sampling rate for changes in the stack gas variables.
SAMPLING METER CONSOLE OPERATION
The sampling meter console must be calibrated and thoroughly leak tested Meter console
operating procedures will differ somewhat according to manufacturer. The pro-
cedures discussed here will aid in operating most types of consoles. The objective is
to understand console operating procedures for isokinetic source sampling.
Sampling Train Leak Tests
Completely assemble the sampling train as intended for use during the test. Turn
on probe and filter heating systems and allow them to reach operating
temperatures. Disconnect the umbilical cord vacuum line and turn on the meter
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console pump. This allows the pump to lubricate itself and to warm up (this is
especially important in cold weather). Leak test the pitot tubes and lines during
this warm up.
The pitot tube impact pressure leg is leak tested by applying a positive pressure.
Blow into the impact opening until > 7.6 cm (3 inches) 1^0 is indicated by the
differential pressure gage. Seal the impact opening. The pressure should be stable
for at least 15 seconds. The static pressure leg of the pitot tube is leak tested in a
similar way by drawing a negative pressure > 7.6 cm H<>0. Correct any leaks.
The sampling train is leak tested when it has reached operating temperature.
Turn off the console pump; connect the umbilical vacuum line. With the coarse
control value completely off, turn the fine adjustment (bypass) valve completely
counterclockwise. Plug the nozzle inlet and turn on the console pump. Slowly turn
the coarse adjustment valve fully open. Gradually turn the fine adjustment valve
clockwise until 380 mm (15 inches) Hg vacuum appears on the vacuum gage. If
this vacuum is exceeded, do not turn the fine adjustment valve back
counterclockwise; proceed with the leak test at the vacuum indicated or slowly
release the nozzle plug and restart the leak test. At the desired vacuum observe the
dry gas meter pointer. Using a stopwatch, time the leak rate for at least 60
seconds. The maximum allowable leak is 0.00057 m^/min. (0.02 cfm). Having
determined the leak rate, slowly release the nozzle plug to bleed air into the train;
when the vacuum falls below 130 mm(5 inches) Hg, turn the coarse adjustment
valve completely off. If the leak test is unacceptable, trace all sections of the
sampling train from the filter holder inlet back, (i.e., leak test from the filter inlet,
then the first impinger, etc.) until the leak is found. Correct the leak and retest.
Leak test at the highest vacuum reached during the test after the completing the
sampling procedure. Testing for leaks should also be done any time the train is
serviced (i.e., filter holder change). Record all dry gas meter readings and leak
rates for each leak test.
Train Operation
When the leak tests are completed, the sampling console should be prepared for
sampling. The sampling console differential pressure gages for the pitot tubes and
orifice meter should be checked. Zero and level the gages as required. If the con-
sole does not use oil manometers, the gages must agree with an oil manometer
within 5 percent for at least 3 Ap readings taken in the stack. This check should be
done before testing. Oil manometers should be periodically leveled and re-zeroed
during the test if they are used in the console.
The consoli. operator should then determine the source variables used in solving
the isokinetic rate equation. The isokinetic AH may be determined by using a
nomograph, an electronic calculator, or a source sampling slide rule. The variables
that need to be determined are: stack gas moisture content, average gas velocity
pressure (Ap), stack gas temperature, and estimated average console dry gas mecer
temperature. The stack gas moisture can be determined by Reference Method 4
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sampling or estimated with a wet bulb-dry bulb thermometer technique. The
average Ap and stack gas temperature are determined by a preliminary stack
traverse. The dry gas meter average temperature can be estimated to be 10°C
(25°— 30°F) greater than the ambient temperature at the site. These values are
then used in the nomograph or calculator to find the isokinetic AH.
The operator can now set up the sampling data sheet. Record the dry gas meter
initial reading. Position sampling train at the first sampling point; read the pitot
tube Ap and calculate the corresponding AH. Record starting time of the test.
Turn on the console pump and open the coarse sampling valve while
simultaneously starting a stopwatch. Adjust AH to the proper value using the fine
adjustment valve. Check temperatures and record all data on the data sheet.
The sampling train should be moved to the next sampling point about
15 seconds before the time at point one is over. This allows the pitot tube reading
to stabilize. The dry gas meter volume at the point sampled is read when the stop-
watch shows the point sample time is over. The operator should quickly read the
Ap and calculate AH for the next point, then set the proper sampling rate. Record
all data and proceed as described for all points on the traverse. At the end of the
test, close the coarse valve, stop the pump, and record the stop time. Record the
final dry gas meter reading. Remove the sampling train from the stack and test the
system for leaks. Record the leak rate. After the train has cooled off, proceed to
the cleanup area.
SAMPLING CASE PREPARATION
Inspect and clean the source sampling glassware case before a sampling experi-
ment; remove and clean the sample case glassware. Check the case for needed
repairs and calibrate the filter heater. Store the case completely assembled.
Glassware
All glassware including the filter holder and frit should be disassembled and
cleaned. Separate the individual glass pieces and check for breaks or cracks. Pieces
needing repair are cleaned after repairs have been made. A thorough glass clean-
ing for simple particulate testing is done with soap and water followed by a
distilled water rinse. If analytical work is to be performed on the sample water
condensed, clean the glassware by soaking in a methanol-basic hydroxide (NaOH or
KOH) solution with pH>9. Glass should be left in the base solution until any stains
can be easily washed away, but not any longer than 48 hours as the solution can
etch the glass. The base should be rinsed away with several portions of distilled
water. If ball-joint glassware is used, remove vacuum grease before cleaning with
heptane, hexane, or other suitable solvent. Clean the glass frit by pulling several
aliquots of HNC>3 through the glass frit with a vacuum pump. It should be rinsed
at least three times with double volumes of distilled water and dried before using.
A-14
-------
The rubber gasket surrounding the frit should be cleaned, removing any particles
imbedded in the rubber, which could prevent proper sealing. The frit and gasket
must be constructed such that the glass filter mat does not become compressed in
the sealing area. If this is not the case, or the rubber is in poor condition, discard
the frit.
The Sample Case
The sample case should be checked thoroughly for needed repairs. All handles,
brackets, clamps, and electrical connections must be inspected. Insulation in both
the hot and cold areas must be in good condition. The sample case should not leak
water from the melting ice into the filter heating compartment. The impinger sec-
tion should have protective foam padding on the bottom and a good drainage
system. The drain plug should be clean.
Calibrate the heater in the filter compartment to maintain a temperature around
the filter of 120°± 14°C (248°±25°F)or at other temperatures as specified in the
subparts of Title 40 of the Code of Federal Regulations. This calibration should be
performed at several conditions (to account for seasonal weather changes) so that
the filter compartment temperature can be maintained at the proper level at all
times. Often during sampling the filter section is not easy to see, consequently, the
filter temperature is difficult to monitor accurately. If the case is calibrated for
several conditions, operators can maintain proper temperature control more closely.
Sampling Preparations
The sample case is readied for sampling by filling the impingers with water and
silica gel. Impingers 1 and 2 are each filled with 100 ml of water by inserting a
funnel in the side arm and slowly pouring in the water. This makes it easy to
displace in the impinger and keeps the water from filling the bubbler tube. The
third impinger is left dry. The fourth impinger is filled with 200-300 gm of pre-
weighed silica gel. The silica gel must be added through the side arm. This
prevents dust from collecting on greased ball joints or silica gel from being pulled
up the center tube and out of the impinger. After loading the impingers, securely
fasten the U-joints. Attach the probe to the sampling case and secure the filter
holder in position. Allow the filter compartment and probe to reach operating
temperature. Leak test the assembled train from the probe nozzle by pulling
380 mm Hg (15 in. Hg) vacuum on the system. The maximum allowable leak rate
is 0.00057 m3/min (0.02 cfm). After the leak test, fill the impinger section with
ice and allow time for all temperatures to stabilize.
SAMPLING PROBE PREPARATION
The sampling probe should be thoroughly inspected before field use. Remove the
glass probe liner by loosening the union at the end of the probe. Completely
disassemble the probe union and seal gasket, and inspect all the individual com-
ponents
A-15
-------
Probe Sheath and Pitot Tubes
The stainless steel probe sheath should have a small hole drilled near the end of
the probe. This .prevents a pressure differential inside the sheath from possibly
diluting the sample with air drawn down the probe. If the hole is not there, the
probe end (fitted into the sample case) should be sealed air tight. Check the weld
at the swage fittings for cracks and repair if necessary. Inspect the pitot tubes for
damage and proper construction details (see pitot tube calibration section). Pitot
tubes should be cleaned, checked for cracks or breaks, and securely fastened to the
probe sheath to prevent accidental misalignment in the stack. All pitot tubes and
components must be leak tested.
Examine the union and seal gasket for wear. A stainless steel ring should be in-
cluded in the union-gasket configuration for good compression and an air tight
seal. If a rubber o-ring gasket is used (stack temperatures < 350 °F) it should be
inspected for wear and replaced if necessary. Asbestos string gaskets must be
replaced each time the union-gasket is disassembled. After inspecting the glass
liner-heating element, reassemble the probe in the following manner to prevent
leaks:
1. Insert glass liner through probe and swage nut;
2. Place stainless steel ring over glass with flat side facing out;
3. Fit gasket over glass liner and push onto steel ring;
4. Align glass liner end with edge of swage nut closest to pitot tube orifice
openings;
5. Screw the union on finger tight;
6. Use probe wrenches to tighten the union. If too much tightening is done
here, the end of the glass liner will break.
Glass Liner-Heating Element
The glass liner should be thoroughly cleaned with a probe brush, acetone, and
distilled t^O. If it will not come clean in this manner, it should be cleaned with
dilute HC1 or replaced. The glass liner-heating element in many sampling probes
can not be separated, making thorough cleaning difficult. An easily separated
liner-heater is a great advantage.
The heating element should be checked for good electrical insulation; the insula-
tion on a frequently used probe liner heating element will eventually be worn or
burned away. This can expose frayed wires, which may short against the probe
sheath. These hazards can be avoided with careful inspections and repair. After
thorough inspection, check the heating element in the reassembled probe. This
procedure is helpful in finding problems before arrival at the sampling site. Atten-
tion should be given to the function of the electrical system and wrappings around
the glass liner; these wraps help prevent electrical shorts against the probe sheath
while minimizing glass liner flexing that can cause a liner break or electrical short.
A-16
-------
Summary
A thorough probe check before a sampling experiment helps prevent field
problems. Disassemble the probe and inspect all components. Make certain con-'
struction details and integrity are correct. Clean the glass liner thoroughly. Check
the heating element electrical connections. Test the reassembled probe for leaks
and proper heating.
CLEANING AND ANALYTICAL PROCEDURES
FOR THE METHOD 5 SAMPLING TRAIN
The clean-up and analysis of the sample taken with the Method 5 Sampling Train
is an integral part of the entire experiment. The precise operation of Method 5
Sampling equipment must be complemented by a careful clean-up of the train
components. Analysis of the sample using approved procedures and good
laboratory technique provides accurate laboratory data. Good testing at the stack
must be followed by accurate analysis in the laboratory so that valid data may be
presented.
Cleaning the Sampling Train
The sequence of procedures in cleaning the sampling train is best presented in an
outline-flowchart form. Each step is presented with appropriate comments.
Additional Comments
The flowchart (Figure 5-3) gives the general procedure for sample clean-up. Many
factors can affect the accuracy of the final sample obtained. Care and experience
are very important when cleaning the sample train. A number of helpful tips are
given below;
1. Always perform clean-up procedures in a clean, quiet area. The best
area is a laboratory.
2. Make a probe holder for the probe cleaning procedure or be sure two
people perform the procedure; this prevents spills and accidents.
3. Clean all equipment in an area where an accidental spill may be
recovered without contaminating the original sample.
a. Open and clean the filter holder over clean glassine or waxed
paper so that a spill can be recovered.
b. Clean probe into a container sitting on the same type of glassine
paper.
4. Clean the probe equipment thoroughly:
a. Brush probe a minimum of three times.
b. Visually inspect the probe interior.
c. Record appearance and confidence of cleanliness.
d. Repeat brushing until cleaning is complete.
e. Confidence ^ 99%. Check with tared cotton swab brushed through
probe.
A-17
-------
Figure 5-3. Cleaning the sample train.
Testing completed
Perform final leak check on sampling train
with vacuum 2: test vacuum. Leak rate must
be •£ 0.02 cfm.
Inspect sample and record observations
Impinger water color
and turbidity
Filter appearance
Appearance of probe
and all other glassware
Allow hot probe
to cool sufficiently
Disassemble sampling train (log all information in test log)
T
Z. Be sure cap wiu not
melt to nozzle.
3. Be rare paniculate
will not stick to cap
| Clean probe exterior
Blow out
pilot tubes
Wash exeat
dust off probe
sheath and
nozzle
Carefully remove nozzle
and probe end cap*
Do not allow pani-
culate to be lost
Cap
probe
end
Disassemble
filter
Cap filter
inlet and
outlet
Filter mat placed in
clean, tared
weighing dish
1
Additional am
optional
1
Organic -Inori
extraction
Glass components are
scrubbed thoroughly with
acetone washings added
to tared probe wash beaker
Desiccate 24 hrs. over
16 mesh calcium
sulfate or other
anhydrous desiccant
Clean probe with nozzle
in place using acetone
and brush attached to
stainless steel or teflon
handle
Brush entire length of
probe with acetone 2 S
times into marked
container or clean,
tared beaker
Remove nozzle and inspect it
and probe liner
Weigh and record
Desiccate 6 hrs.
J
Weigh, and record.
Continue to constant weight—
weights differ £ 0.5 mg
dean probe liner again until no
sign of particuUta can be seen in the
acetone or on the glass
Clean nozzle by rinsing with acetone
1. Brush interior from blunt back side only.
2. Never force brush into sharp nozzle end;
bristles will be cut contaminating sample.
All washings (filter glassware included)
added to clean, marked, tared beaker
Evaporate acetone at room temperature
and pressure
Desiccate and weigh to constant weight
as with filler
A-18
-------
5. Clean filter equipment thoroughly.
a. Brush all glassware until clean.
b. Check with tared cotton swab.
c. Remove all filter mats adhering to rubber seal ring. This is
extremely important for accurate particulate weighing.
d. Do not scrape glass frit into sample.
6. The laboratory scale accuracy and sensitivity should be checked before
each analysis using standard weights. Actual weight and scale reading
should agree to ± 0.5 mg.
7. Careful labeling of all train components, tared beakers, and sample
containers avoids problems and confusion.
8. Permanently marked weighing glassware with permanent record of their
new, clean, reference tare weight allows a check of cleanliness when
tared just prior to use. This can also be helpful in checking any
weighing discrepancies in the analysis (re-tare reference periodically).
9. Acetone is the solvent recommended for cleaning; however, water
washing may be suggested by the type of pollutant sampled and should
be added to the procedure if indicated.
10. Adding heat to the evaporation of solvent could evaporate volatile
materials and give erroneous data.
11. The laboratory must have:
a. An analytical balance with minimum precision to 0.5 mg,
b. Large desiccating container that is air tight.
12. Use only American Chemical Society Reagent grade organic solvent.
13. Use deionized, glass-distilled H2O.
14. Evaporate a control blank of 100 ml of each solvent used in any part of
the analysis in tared beaker at room termperature and pressure.
15. Use only glass wash bottles and glass containers for all procedures that
involve analytical workup. Only silica gel may be stored in plastic
containers.
16. Organic-inorganic extraction of the impinger may be useful in deter-
mining emissions from some sources. Use the flowchart as a guide to
this procedure.
A-19
-------
Impinger H2O
Record total volume
Add to 500 ml separatory funnel
Add 50 ml anhydrous diethyl ether
Shake 3 minutes venting ether fumes periodically
Let stand for separation of layers
H2<3 bottom layer separated Et2O to tared beaker
Extract H2O twice again for a total
of three Et2O extractions.
Combine extracts.
H2O is then extracted three times with
50 ml chloroform (CHC13)
I
H2O to tared beaker CHCIs + Et2O extracts
Evaporate H2O at room temperature and Evaporate at room temperature
pressure and pressure
17. Procedures given here are only for cleaning Method 5 Train,
although, they are good general starting point procedures for cleaning
any sampling train.
The most important aspect of cleaning and analyzing the Method 5 Sampling
Train is the practice of good laboratory technique. The sampling team may not in-
clude an experienced chemist; therefore, good technique may have to be learned
by all team members. If an experienced analytical chemist is a member of the
sampling team it would probably be best to allow him to assist in cleaning the
equipment. This would help to assure good techniques and perhaps save time in
preparing samples for more extensive qualitative or quantitative analysis.
SAFETY ON SITE
Source sampling is performed at a variety of industrial sites and under many dif-
ferent conditions. Adequate safety procedures may be different for any given situa-
tion; however, generally accepted industrial safety procedures should be helpful to
source samplers. The test team must be aware of safe operating methods so that
alert discretion may be used for team safety at a particular sampling site. Safety is
an attitude that must be instilled in all sample team members. Well thought out
and followed procedures will ensure the safety of all team members. The team con-
cept essential to successful testing is vital for safe testing. It ,rust be stressed that
safety is everyone's responsibility for themselves as well as for other team members.
A-20
-------
Key Factors to Good Safety
Knowledge and experience are the major factors in formulating sound safety prac
tice. An individual must draw upon these factors in determining safe methods. A
knowledge of standard safety and operating procedures will permit their applica-
tion in any situation. This basic knowledge in conjunction with understanding of
the job tasks and possible dangers assists in planning preventive safety measures.
Plans for operating at the job site may be developed around these procedures. If an
accident does occur, the people involved must be informed of proper emergency
practices and use of first aid. Job experience and analysis of past accidents should
be used in developing preventive safety programs.
Accident Analysis
The basic philosophy of a safety program should be that accidents are caused and,
therefore, can be avoided or prevented. Accident analysis is a productive tool of
this philosophy when it is used as a preventive step. This implies advance examina-
tion of a potentially hazardous situation to predict possible accidents and eliminate
their causes. Accident analysis is most effective when employed after an accident
has taken place. The analysis procedure involves listing the major and con-
tributing causes of the accident. If the real causes of the accident are analyzed in
this manner, corrective action will suggest itself. Accident analysis should include
preventive suggestions from people involved at the job site or those who have been
previously injured.
Common Causes of Accidents
There are a number of items that may be considered common causes of accidents:
1. Failure of supervisory personnel to give adequate instructions or inspec-
tions. This includes instructions for performing the job and safety re-
quirements. Inspection of the job site is advisable for all applicable con-
cerns and safety before, during, and after the job.
2. Failure of person in charge to properly plan or conduct the activity. Ex-
periment design and performance are important factors in success and
safety of a stack test. This includes providing adequate manpower for
the task.
3. Improper design, construction, or layout. Design aspects relate to equip-
ment used and plan of operation.
4. Protective devices or proper tools and equipment not provided. "Jerry
rigging" and "making do" should only occur under unusual cir-
cumstances, not as standard practice.
5. Failure on the part of any personnel to follow rules or instructions.
Safety is the responsiblity of each individual for himself and others
around him. Personal disregard for safety rules jeopardizes the safety of
all.
A-21
-------
6. Neglect or improper use of protective devices, job equipment, or
materials.
7. Faulty, improperly maintained devices. Poorly maintained job equip-
ment is inexcusable.
8. Personnel without adequate knowledge or training for performing job.
tasks. All present should be capable of performing the job tasks
assigned. Trainees should be closely supervised.
9 Personnel in poor physical condition or with a poor mental attitude for
task. This can have implications for the attitude of personnel toward
each other, the supervisor, the task itself, or working conditions.
10. Unpredictable agents outside the organization. This may mean contract
personnel who do not abide by standard rules or something as unpredic-
table as a biting insect or bad weather.
Accident Prevention
Preventing accidents during a stack test begins with advance planning.
Knowledge of process operations and important considerations of the site
environment will give insight into chemical, mechanical, or electrical hazards
that may be present. This knowledge will be useful in deciding on equipment to
be used at the site. Knowledge of the weather conditions and logistical con-
straints further aid in establishing a safe test program. These items in conjunc-
tion with evaluation of site safety and first aid facilities will allow preparation of
a source sampling experiment.
The source test program will operate at peak efficiency and safety if plans are
properly followed. Thorough planning, including contingency actions, eliminates
the confusion that often contributes to accidents. This planning must include
allotment of sufficient time for completion of the task, taking into account
possible delays. Test personnel should be well informed of the program pro-
cedures; their input for test performance and safety suggestions will be useful.
Having once established an operating plan, all involved should adhere to it closely.
After thorough planning of the test program, attention focuses upon testing and
safety equipment and on site operating practices. General comments on equipment
preparation apply to both the sampling and safety apparatus. Experimental design
and personnel suggestions should indicate what equipment will be needed on the
site for all functions. Equipment should be prepared and assembled in advance; it
should be checked for suitable operation or potential problems. Equipment that
could handle unexpected situations should also be included. Carry only necessary
equipment to the site and use it properly.
Work at the site must be organized following standard rules and work the plan
carefully followed. Safety equipment should be used and personnel must remain
alert to any changes on the site that could effect safe operation. All present should
be made aware of any suspected problems.
A-22
-------
Summary
The most important factor in any safety program is common sense. Common sense
can, however, be an elusive element. Several steps presented in this section can
help in developing sensible safety practices. Thorough advance planning and
preparation for the jobs at hand begin the process of good safety practice.
Informing involved personnel of all plans and using their suggestions about work
safety increases the effectiveness of the planning. Analyzing a work situation for
hazards, including past problems, into a coherent, organized safety program,
usually results in common sense corrective procedures.
A-23
-------
SLIDE 101-0 NOTES
INTRODUCTION TO
SOURCE SAMPLING
SLIDE 101-1
PURPOSE OF SOURCE SAMPLING
THE AGENCY
1. Provide data to formulate control strategy.
2. Provide data to evaluate compliance.
3. Provide data upon which regulations can be based.
SLIDE 101-2
PURPOSE OF SOURCE SAMPLING
INDUSTRY
1. Provide information on process operations.
2. Provide information on control device efficiency.
3. Provide information for design of new process and
control equipment.
A-25
-------
SLIDE 101-3
NOTES
BASIC TERMINOLOGY
CONCENTRATION
Quantity of pollutant per quantity of effluent gas.
grams/cubic foot
STACK GAS FLOW RATE
Quantity of effluent gas per length of time.
cubic feet/hour
POLLUTANT MASS RATE
Quantity of pollutant per length of time.
pounds/hour
SLIDE 101-4
POLLUTANT MASS RATE EQUATION
Pmrs - Cs Qs
SLIDE 101-5
STACK SAMPLING FLOW DIAGRAM
0,
= A.v.
C. T P
pmr.
= c.Q.
M
COMPOSITION
A-27
-------
SECTION B. METHOD 1
Subject Page
1. Method 1—sample and velocity traverses for stationary sources
(taken from the Environmental Protection Agency Performance
Test Methods manual) B-3
2. Slides B-15
B-l
-------
METHOD 1—SAMPLE AND VELOCITY TRAVERSES
FOR STATIONARY SOURCES
1. Principle and Applicability
1.1 Principle. To aid in the representative measurement of
pollutant emissions and/or total volumetric flow rate from a
stationary source, a measurement site where the effluent stream
is flowing in a known direction is selected, and the cross-section
of the stack is divided into a number of equal areas. A traverse
point is then located within each of these equal areas.
1.2 Applicability. This method is applicable to flowing gas
streams in ducts, stacks, and flues. The method cannot be used when:
(1) flow is cyclonic or swirling (see Section 2.4), (2) a stack is
p
smaller than about 0.30 meter (12 in.) in diameter, or 0.071 m
2
(113 in. ) in cross-sectional area, or (3) the measurement site is less
than two stack or duct diameters downstream or less than a half
diameter upstream from a flow disturbance.
The requirements of this method must be considered before con-
struction of a new facility from which emissions will be measured;
failure to do so may require subsequent alterations to the stack or
deviation from the standard procedure. Cases involving variants are
subject to approval by the Administrator, U.S. Environmental Protection
Agency.
2. Procedure
2.1 Selection of Measurement Site. Sampling or velocity measure-
ment is performed at a site located at least eight stack or duct
B-3
-------
diameters downstream and two diameters upstream from any flow
disturbance such as a bend, expansion, or contraction in the stack,
or from a visible flame. If necessary, an alternative location may
be selected, at a position at least two stack or duct diameters
downstream and a half diameter upstream from any flow disturbance.
For a rectangular cross section, an equivalent diameter (De) shall
be calculated from the following equation, to determine the upstream
and downstream distances:
n - 2LM
De " "HTw
where L = length and W = width.
2.2 Determining the Number of Traverse Points.
2.2.1 Particulate Traverses. When the eight- and two-diameter
criterion can be met, the minimum number of traverse points shall be:
(1) twelve, for circular or rectangular stacks with diameters (or
equivalent diameters) greater than 0.61 meter (24 in.); (2) eight,
for circular stacks with diameters between 0.30 and 0.61 meter
(12-24 in.); and (3) nine, for rectangular stacks with equivalent
diameters between 0.30 and 0.61 meter (12-24 in.).
When the eight- and two-diameter criterion cannot be met, the
minimum number of traverse points is determined from Figure 1-1.
Before referring to the figure, however, determine the distances from
the chosen measurement site to the nearest upstream and downstream
disturbances, and divide each distance by the stack diameter or
equivalent diameter, to determine the distance in terms of the number
of duct diameters. Then, determine from Figure 1-1 the minimum number
B-4
-------
en
en
0.5
50
V)
40
o
a.
UJ
cc
UJ
> 30
O
oc
20
S 10
DUCT DIAMETERS UPSTREAM FROM FLOW DISTURBANCE (DISTANCE A}
1.0 1.5 2.0
* FROM POINT OF ANY TYPE OF
DISTURBANCE (BEND, EXPANSION. CONTRACTION. ETC.
I
25
I
Y
T
A
-
*
\
-
5
1
—
1
1
4
'DISTURBANCE
MEASUREMENT
:- SITE
DISTURBANCE
I
3456789
DUCT DIAMETERS DOWNSTREAM FROM FLOW DISTURBANCE (DISTANCE B)
Figure 1-1. Minimum number of traverse points for particulate traverses.
10
-------
of traverse points that corresponds: (1) to the number of duct
diameters upstream; and (2) to the number of diameters downstream.
Select the higher of the two minimum numbers of traverse points, or
a greater value, so that for circular stacks the number is a
multiple of 4, and for rectangular stacks, the number is one of those
shown in Table 1-1.
Table 1-1. CROSS-SECTIONAL LAYOUT FOR RECTANGULAR STACKS
No. of traverse Matrix
points layout
9 3x3
12 4x3
16 4x4
20 5x4
25 5x5
30 6x5
36 6x6
42 7x6
49 7x7
2.2.2 Velocity (Non-Particulate) Traverses. When velocity or
volumetric flow rate is to be determined (but not particulate matter),
the same procedure as that for particulate traverses (Section 2.2.1)
is followed, except that Figure 1-2 may be used instead of Figure 1-1.
2.3 Cross-Sectional Layout and Location of Traverse Points.
2.3.1 Circular Stacks. Locate the traverse points on two perpendi
cular diameters according to Table 1-2 and the example shown in
Figure 1-3. Any equation (for examples, see Citations 2 and 3 in the
B-6
-------
D3
I
05
DUCT DIAMETERS UPSTREAM FROM FLOW DISTURBANCE (DISTANCE A)
1.0 1.5 2.0
50
40
O
a.
LLJ
V)
oc
UJ
O
oc
D
S
D
5
30
20
? 10
T
I
_L
25
\
J
A
"•
f
3
i
i
i
—
|
1
fc
'DISTURBANCE
MEASUREMENT
"-- SITE
DISTURBANCE
2 3 4 5 6 78 9
DUCT DIAMETERS DOWNSTREAM FROM FLOW DISTURBANCE (DISTANCE B)
10
Figure 1-2. Minimum number of traverse points for velocity (nonparticulate) traverses.
-------
TRAVERSE
POINT
1
2
3
4
5
6
DISTANCE.
% of diameter
4.4
14.7
29.5
70.5
85.3
95.6
Figure 1-3. Example showing circular stack cross section divided into
12 equal areas, with location of traverse points indicated.
B-8
-------
Table 1-2. LOCATION OF TRAVERSE POINTS IN CIRCULAR STACKS
(Percent of stack diameter from inside wall to traverse point)
Traverse
point
number
on a
diameter
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Number of traverse points on a diameter
2
14.6
85.4
4
6.7
25.0
75.0
93.3
6
4.4
14.6
29.6
70.4
85.4
95.6
8
3.2
10.5
19.4
32.3
67.7
80.6
89.5
96.8
10
2.6
8.2
14.6
22.6
34.2
65.8
77.4
85.4
91.8
97.4
12
2.1
6.7
11.8
17.7
25.0
35.6
64.4
75.0
82.3
88.2
93.3
97.9
14
1.8
5.7
9.9
14.6
20.1
26.9
36.6
63.4
73.1
79.9
85.4
90.1
94.3
98.2
16
1.6
4.9
8.5
12.5
16.9
22.0
28.3
37.5
62.5
71.7
78.0
83.1
87.5
91.5
95'. 1
98.4
18
1.4
4.4
7.5
10.9
14.6
18.8
23.6
29.6
38.2
61.8
70.4
76.4
31.2
85.4
89.1
92.5
95.6
98.6
20
1.3
3.9
6.7
9.7
12.9
16.5
20.4
25.0
30.6
38.8
61.2
69.4
75.0
79.6
83.5
87.1
90.3
93.3
96.1
98.7
22
1.1
3.5
6.0
8.7
11.6
14.6
18.0
21.8
26.2
31.5
39.3
60.7
68.5
73.8
78.2
82.0
85.4
88.4
91.3
94.0
96.5
98.9
24
1.1
3.2
5.5
7.9
10.5
13.2
16.1
19.4
23.0
27.2
32.3
39.8
60.2
67.7
72.8
77.0
80.6
83.9
86.8
89.5
92.1
94.5
96.8
98.9
B-9
-------
Bibliography) that gives the same values as those in Table 1-2 may
be used in lieu of Table 1-2.
For particulate traverses, one of the diameters must be in a plane
containing the greatest expected concentration variation, e.g., after
bends, one diameter shall be in the plane of the bend. This requirement
becomes less critical as the distance from the disturbance increases;
therefore, other diameter locations may be used, subject to approval of
the Administrator.
In addition, for stacks having diameters greater than 0.61 m
(24 in.) no traverse points shall be located within 2.5 centimeters
(1.00 in.) of the stack walls; and for stack diameters equal to or less
than 0.61 m (24 in.), no traverse points shall be located within 1.3 cm
(0.50 in.) of the stack walls. To meet these criteria, observe the
procedures given below.
2.3.1.1 Stacks With Diameters Greater Than 0.61 m (24 in.). When
any of the traverse points as located in Section 2.3.1 fall within
2.5 cm (1.00 in.) of the stack walls, relocate them away from the
stack walls to: (1) a distance of 2.5 cm (1.00 in.); or (2) a distance
equal to the nozzle inside diameter, whichever is larger. These
relocated traverse points (on each end of a diameter) shall be the
"adjusted" traverse points.
Whenever two successive traverse points are combined to form a
single adjusted traverse point, treat the adjusted point as two
separate traverse points, both in the sampling (or velocity measure-
ment) procedure, and in recording the data.
B-10
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2.3.1.2 Stacks With Diameters Equal to or Less Than 0.61 m (24
in.). Follow the procedure in Section 2.3.1.1, noting only that any
"adjusted" points should be relocated away from the stack walls to:
(1) a distance of 1.3 cm (0.50 in.); or (2) a distance equal to the
nozzle inside diameter, whichever is larger.
2.3.2 Rectangular Stacks. Determine the number of traverse points
as explained in Sections 2.1 and 2.2 of this method. From Table 1-1,
determine the grid configuration. Divide the stack cross-section into as
many equal rectangular elemental areas as traverse points, and then
locate a traverse point at the centroid of each equal area according to
the example in Figure 1-4.
If the tester desires to use more than the minimum number of
traverse points, expand the "minimum number of traverse points" matrix
(see Table 1-1) by adding the extra traverse points along one or the
other or both legs of the matrix; the final matrix need not be balanced.
For example, if a 4 x 3 "minimum number of points" matrix were expanded
to 36 points, the final matrix could be9x4or!2x3, and would not
necessarily have to be 6 x 6. After constructing the final matrix,
divide the stack cross-section into as many equal rectangular, elemental
areas as traverse points, and locate a traverse point at the centroid of
each equal area.
The situation of traverse points being too close to the stack walls
is not expected to arise with rectangular stacks. If this problem
should ever arise, the Administrator must be contacted for resolution of
the matter.
B-ll
-------
I [__
o ' o o
I
I
Figure 1 -4. Example showing rectangular stack cross
section divided into 12 equal areas, with a traverse
point at centroid of each area.
B-12
-------
2.4 Verification of Absence of Cyclohic Flow. In most stationary
sources, the direction of stack gas flow is essentially parallel to the
stack walls. However, cyclonic flow may exist (1) after such devices as
cyclones and inertial demisters fbllowing venturi scrubbers, or (2) in
stacks having tangential inlets or other duct configurations which tend
to induce swirling; in these instances, the presence or absence of
cyclonic flow at the sampling location must be determined. The following
techniques are acceptable for this determination.
Level and zero the manometer. Connect a Type S pi tot tube to the
manometer. Position the Type S pi.tot tube at each traverse point, in
succession, so that the planes of the face openings of the pi tot tube
are perpendicular to the stack cross-sectional plane: when the Type S
pitot tube is in this position, it is at "0° reference." Note the
differential pressure (Ap) reading at each traverse point. If a null
(zero) pitot reading is obtained at 0° reference at a given traverse
point, an acceptable flow condition exists at that point. If the pitot
reading is not zero at 0° reference, rotate the pitot tube (up to +90°
yaw angle), until a null reading is obtained. Carefully determine and
record the value of the rotation angle (a) to the nearest degree. After
the null technique has been applied at each traverse point, calculate
the average of the absolute values of o; assign a values of 0° to those
points for which no rotation was required, and include these in the
overall average. If the average value of a is greater than 10°, the
overall flow condition in the stack is unacceptable and alternative
methodology, subject to the approval of the Administrator, must be used
to perform accurate sample and velocity traverses.
B-13
-------
3. Bibliography
1. Determining Dust Concentration in a Gas Stream. ASME. Per-
formance 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. Participate Sampling Strategies for
Large Power Plants Including Nonuniform Flow. USEPA, ORD, ESRL, Research
Triangle Park, N.C. EPA-600/2-76-170. June 1976.
6. Entropy Environmentalists, Inc. Determination of the Optimum
Number of Sampling Points: An.Analysis of Method 1 Criteria. Environmental
Protection Agency. Reserch Triangle Park, N. C. EPA Contract No. 68-01-317
Task 7.
B-14
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SLIDE 102-0
NOTES
METHOD — 1
Sample and Velocity Traverses
for Stationary Sources
SLIDE 102-1
CRITERIA FOR SELECTION OF
MEASUREMENT SITE
• Effluent stream must be flowing in a known direction.
• Ideally, site should be at least eight stack diameters
downstream and two diameters upstream from any
flow disturbance.
• Alternatively, site must be located at a minimum of two
stack diameters downstream and one-half diameter
upstream from any flow disturbance.
SLIDE 102-2
UPSTREAM AND DOWNSTREAM FLOW DISTURBANCES
DISTURBANCE
UPSTREAM
DISTANCE
DOWNSTREAM
DISTANCE
B-15
-------
SLIDE 102-3
NOTES
EXAMPLE FOR CIRCULAR STACKS
Inside of far wall to outside of nipple (distance 1)
Inside of near wall to outside of nipple (distance 2) =
Stack ID (distance 1 - distance 2)
Nearest upstream disturbance (distance A)
Nearest downstream disturbance (distance B)
CALCULATION
74" (distance A) -f- 36" (stack ID) = 2
288" (distance B) -~ 36" (stack ID) = 8
39"
3"
36"
74"
288"
SLIDE 102-4
MINIMUM NUMBER OF TRAVERSE POINTS
0.5
501—
DUCT DIAMETERS UPSTREAM FROM FlOW DISTURBANCE (DISTANCE Al
10 1.5 2.0
2.5
-USE FOR PARTICULATE
• USE FOR NONPARTICULATE
\ 7 DISTURBANCE
II
1
,
I
i
1
J
*
^
SAMPLING
SITE
DISTURBANCE
&
3 4 5 6 7 B 9
DUCT DIAMETERS DOWNSTREAM FROM FLOW DISTURBANCE (DISTANCE Bl
B-17
-------
SLIDE 102-5
NOTES
LOCATION OF TRAVERSE POINTS
AS A PERCENTAGE OF STACK DIAMETER
Traverse
point
number
on a
diameter 2
1 14.6
2 85.4
3
4
5
6
7
8
9
10
11
12
Number of traverse points
on a diameter
4
6.7
25.0
75.0
93.3
6
4.4
14.6
29.6
70.4
85.4
95.6
8
3.2
10.5
19.4
32.3
67.7
80.6
89.5
96.8
10
2.6
8.2
14.6
22.6
34.2
65.8
77.4
85.4
91.8
97.4
12
2.1
6.7
11.8
17.7
25.0
35.6
64.4
75.0
82.3
88.2
93.3
97.9
SLIDE 102-6
MEASURED LOCATIONS OF TRAVERSE POINTS
(CIRCULAR STACK)
TRAVERSE
POINT
1
2
3
4
5
6
DISTANCE
DIAMETER
4.4
14.7
29.5
70.5
85.3
95.6
B-19
-------
SLIDE 102-7 NOTES
CRITERIA FOR LOCATING SAMPLE POINTS IN
CIRCULAR STACKS
• One diameter must be in a plane containing greatest
expected concentration variation, for particulate
traverses.
• No traverse point shall be located within 2.5 cm (1.0 in.)
of stack wall for stacks greater than 0.61 m (24 in.) in
diameter.
• No traverse point shall be located within 1.3 cm
(0.50 in.) of stack wall for stacks with diameters < 0.61 m
(24 in.).
SLIDE 102-8
(cont.)
• Relocated traverse points shall be defined as
"adjusted" traverse points.
• When two traverse points are combined to form
a single adjusted traverse point, treat adjusted
point as two points.
SLIDE 102-9
BALANCED MATRIX SCHEME FOR
RECTANGULAR STACKS
Number of Matrix
Traverse Points Layout
9
12
16
20
25
30
36
42
49
3x3
4x3
4x4
5x4
5x5
6x5
6x6
7x6
7x7
B-21
-------
SLIDE 102-10
NOTES
EXAMPLE FOR RECTANGULAR STACKS
Dimensions:
Length of stack (L) (- wall thickness) = 36"
Width of stack (W) (- wall thickness) - 36"
Equivalent Diameter (De)
De -
2LW
36x36
= 36"
L + W 36 + 36
Nipple Length
Nearest upstream disturbance (distance A)
Nearest downstream disturbance (distance B)
74" (distance A) -^ 36" {stack De)
288" (distance B) -^ 36" (stack De)
= 0
= 74"
= 288"
= 2
= 8
SLIDE 102-11
TRAVERSE POINT LOCATIONS (RECTANGULAR STACK)
B-23
-------
SLIDE 102-12 NOTES
MEASURED LOCATIONS OF
TRAVERSE POINTS
(RECTANGULAR STACK)
Point Length of nipple Distance X Distance Y
1-1 0 4.5" 6"
1-2 0 4.5" 18"
1-3 0 4.5" 30"
2-1 0 13.5" 6"
2-2 0 13.5" 18"
2-3 0 13.5" 30"
3-1 0 22.5" 6"
3-2 0 22.5" 18"
3-3 0 22.5" 30"
4-1 0 31.5" 6"
4-2 0 31.5" 18"
4-3 0 31.5" 30"
SLIDE 102-13
NON PARALLEL FLOW
Presence or absence of non parallel flow must
be determined after:
• Cyclones
• Inertial Demisters
• Stacks Having Tangential Inlets
SLIDE 102-14
VERIFY SUITABILITY OF SITE
1. Calculate absolute value of«.
2. If average value of <* is > 10°, flow condi-
tions are unacceptable.
B-25
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SECTION C. METHOD 2
Subject Page
1. Method 2--determination of stack gas velocity and volumetric
flow rate (Type S pi tot tube) (taken from the Environmental
Protection Agency Performance Test Methods manual) C-3
2. Slides C-35
C-l
-------
METHOD 2—DETERMINATION OF STACK GAS VELOCITY AND
VOLUMETRIC FLOW RATE (TYPE S PITOT TUBE)
1. Principle and Applicability
1.1 Principle. The average gas velocity in a stack is
determined from the gas density and from measurement of the average
velocity head with a Type S (Stausscheibe or reverse type) pi tot tube.
1.2 Applicability. This method is applicable for measurement
of the average velocity of a gas stream and for quantifying gas flow.
This procedure is not applicable at measurement sites which fail
to meet the criteria of Method 1, Section 2.1. Also, the method cannot
be used for direct measurement in cyclonic or swirling gas streams;
Section 2.4 of Method 1 shows how to determine cyclonic or swirling
flow conditions. When unacceptable conditions exist, alternative
procedures, subject to the approval of the Administrator, U. S.
Environmental Protection Agency, must be employed to make accurate
flow rate determinations; examples of such alternative procedures are:
(1) to install straightening vanes; (2) to calculate the total volumetric
flow rate stoichiometrically, or (3) to move to another measurement
site at which the flow is acceptable.
2. Apparatus
Specifications for the apparatus are given below. Any other
apparatus that has been demonstrated (subject to approval of the
Administrator) to be capable of meeting the specifications will be
considered acceptable.
2.1 Type S Pitot Tube. The Type S pitot tube (Figure 2-1) shall
be made of metal tubing (e.g., stainless steel). It is recommended
that the external tubing diameter (dimension D., Figure 2-2b) be
t
C-3
-------
1.90 2.54cm*
(0 75 1.0 in.)
^A'^-.-j. . ..b —I
rmfm*.~A:,wj--,lTLr
7.62 cm (3 in.)*
TEMPERATURE SENSOR
TYPE SPITOTTUBE
'SUGGESTED (INTERFERENCE FREE)
PITOT TUBE THERMOCOUPLE SPACING
LEAK-FREE
CONNECTIONS
MANOMETER
Figure 2-1. Type S pitot tube manometer assembly.
C-4
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between 0.48 and 0.95 centimeters (3/16 and 3/8 inch). There shall
be an equal distance from the base of each leg of the pitot tube to
its face-opening plane (dimensions P. and PB, Figure 2-2b); it is
recommended that this distance be between 1.05 and 1.50 times the
external tubing diameter. The face openings of the pi tot tube shall,
preferably, be aligned as shown in Figure 2-2; however, slight mis-
alignments of the openings are permissible (see Figure 2-3).
The Type S pi tot tube shall have a known coefficient, determined
as outlined in Section 4. An identification number shall be assigned
to the pitot tube; this number shall be permanently marked or
engraved on the body of the tube.
A standard pitot tube may be used instead of a Type S, provided
that it meets the specifications of Sections 2.7 and 4.2; note, however,
that the static and impact pressure holes of standard pitot tubes are
susceptible to plugging in particulate-laden gas streams. Therefore,
whenever a standard pitot tube is used to perform a traverse, adequate
proof must be furnished that the openings of the pitot tube have not
plugged up during the traverse period; this can be done by taking a
velocity head (AP) reading at the final traverse point, cleaning out
the impact and static holes of the standard pitot tube by "back-
purging" with pressurized air, and then taking another AP reading.
If the Ap readings made before and after the air purge are the same
(+5 percent), the traverse is acceptable. Otherwise, reject the run.
Note that if Ap at the final traverse point is unsuitably low,
another point may be selected. If "back-purging" at regular intervals
C-5
-------
TRANSVERSE
TUBE AXIS
\
FACE
OPENING
PLANES
(a)
A SIDE PLANE
LONGITUDINAL '
TUBE AXIS
7 Dt A
S * B
PA
PB
NOTE:
1.05 Dt < P<1.50Dt
B SIDE PLANE
(b)
A ORB
(c)
Figure 2-2. Properly constructed Type S pilot tube, shown
in: (a) end view; face opening planes perpendicular to trans-
verse axis; (b) top view; face opening planes parallel to lon-
gitudinal axis; (c) side view; both legs of equal length and
center lines coincident, when viewed from both sides. Base-
line coefficient values of 0.84 may be assigned to pitot tubes
constructed this way.
C-6
-------
TRANSVERSE
TUBE AXIS
(a)
LONGITUDINAL
TUBE AXIS —
(c)
9
FLOW
(d)
01W
•-4E
(e)
(f)
(g)
Figure 2-3. Types of face-opening misalignment that can result from field use or im-
proper construction of Type S pitot tubes. These will not affect the baseline value
of Cp(s) so long as ai anda2< 10°, 01 and 02 < 5°, z< 0.32 cm (1/8 in.) and w <
0.08 cm (1/32 in.) (citation 11 in Section 6).
C-7
-------
is part of the procedure, then comparative Ap readings shall be taken,
as above, for the last two back purges at which suitably high Ap
readings are observed.
2.2 Differential Pressure Gauge. An inclined manometer or
equivalent device is used. Most sampling trains are equipped with
a 10-in. (water column) inclined-vertical manometer,-having 0.01-in.
HgO divisions on the 0- to 1-in. inclined scale, and 0.1-in. HgO
divisions on the 1- to 10-in. vertical scale. This type of manometer
(or other gauge of equivalent sensitivity) is satisfactory for the
measurement of Ap values as low as 1.3 mm (0.05 in.) H^O. However, a
differential pressure gauge of greater sensitivity shall be used
(subject to the approval of the Administrator), if any of the following is
found to be true: (1) the arithmetic average of all Ap readings at
the traverse points in the stack is less than 1.3 mm (0.05 in.) hLO;
(2) for traverses of 12 or more points, more than 10 percent of the
individual Ap readings are below 1.3 mm (0.05 in.) hLO; (3) for traverses
of fewer than 12 points, more than one Ap reading is below 1.3 mm
(0.05 in.) H20. Citation 18 in Section 6 describes commercially
available instrumentation for the measurement of low-range gas velocities.
As an alternative to criteria (1) through (3) above, the following
calculation may be performed to determine the necessity of using a more
sensitive differential pressure gauge:
n
T m
Z /Ap~
1 = 1 1
where:
Ap. = Individual velocity head reading at a traverse point,
mm H2° (in- H2°) C-8
-------
n = Total number of traverse points
K = 0.13 mm H20 when metric units are used and 0.005 in. H^O
when English units are used
If T is greater than 1.05, the velocity head data are unacceptable
and a more sensitive differential pressure gauge must be used.
Note: If differential pressure gauges other than inclined
manometers are used (e.g., magnehelic gauges), their calibration
must be checked after each test series. To check the calibration
of a differential pressure gauge, compare Ap readings of the gauge
with those of a gauge-oil manometer at a minimum of three points,
approximately representing the range of Ap values in the stack. If,
at each point, the values of Ap as read by the differential pressure
gauge and gauge-oil manometer agree to within 5 percent, the differential
pressure gauge shall be considered to be in proper calibration. Other-
wise, the test series shall either be voided, or procedures to adjust
the measured Ap values and final results shall be used, subject to the
approval of the Administrator.
2.3 Temperature Gauge. A thermocouple, liquid-filled bulb
thermometer, bimetallic thermometer, mercury-in-glass thermometer, or
other gauge capable of measuring temperature to within 1.5 percent of
the minimum absolute stack temperature shall be used. The temperature
gauge shall be attached to the pi tot tube such that the sensor tip does not
touch any metal; the gauge shall be in an interference-free arrangement
with respect to the pitot tube face openings (see Figure 2-1 and also
Figure 2-7 in Section 4). Alternate positions may be used if the pitot
tube-temperature gauge system is calibrated according to the procedure
C-9
-------
of Section 4. Provided that a difference of not more than 1 percent
in the average velocity measurement is introduced, the temperature
gauge need not.be attached to the pitot tube; this alternative is
subject to the approval of the Administrator.
2.4 Pressure Probe and Gauge. A piezometer tube and mercury-
or water-filled U-tube manometer capable of measuring stack pressure
to within 2.5 mm (0.1 in.) Hg is used. The static tap of a standard
type pitot tube or one leg of a Type S pitot tube with the face opening
planes positioned parallel to the gas flow may also be used as the
pressure probe.
2.5 Barometer. A mercury, aneroid, or other barometer capable
of measuring atmospheric pressure to within 2.5 mm Hg (0.1 in. Hg) may
be used. In many cases, the barometric reading may be obtained from
a nearby national weather service station, in which case the station
value (which is the absolute barometric pressure) shall be requested
and an adjustment for elevation differences between the weather station
and the sampling point shall be applied at a rate of minus 2.5 mm
(0.1 in.) Hg per 30 meter (100 foot) elevation increase, or vice-versa
for elevation decrease.
2.6 Gas Density Determination Equipment. Method 3 equipment, if
needed (see Section 3.6), to determine the stack gas dry molecular
weight, and Reference Method 4 or Method 5 equipment for moisture content
determination; other methods may be used subject to approval of the
Administrator.
2.7 Calibration Pitot Tube. When calibration of the Type S pitot
tube is necessary (see Section 4), a standard pitot tube is used as a
reference. The standard pitot tube shall, preferably, have a known
C-lo
-------
coefficient, obtained either (1) directly from the National Bureau
of Standards, Route 270, Quince Orchard Road, Gaithersburg,
Maryland, or (2)-by calibration against another standard pitot tube
with an NBS-traceable coefficient. Alternatively, a standard pitot
tube designed according to the criteria given in 2.7.1 through 2.7.5
below and illustrated in Figure 2-4 (see also Citations 7, 8, and 17
in Section 6) may be used. Pitot tubes designed according to these
specifications will have baseline coefficients of about 0/99 j^O.Ol.
2.7.1 Hemispherical (shown in Figure 2-4), ellipsoidal, or
conical tip.
2.7.2 A minimum of six diameters straight run (based upon D, the
external diameter of the tube) between the tip and the static pressure
holes.
2.7.3 A minimum of eight diameters straight run between the static
pressure holes and the centerline of the external tubei following the
90 degree bend.
2.7.4 Static pressure holes of equal size (approximately 0.1 D),
equally spaced in a piezometer ring configuration.
2.7.5 Ninety degree bend, with curved or mitered junction.
2.8 Differential Pressure Gauge for Type S Pitot Tube Calibration.
An inclined manometer or equivalent is used. If the single-velocity
calibration technique is employed (see Section 4.1.2.3), the calibration
differential pressure gauge shall be readable to the nearest 0.13 mm
HpO (0.005 in. HpO). For multivelocity calibrations, the gauge shall be
readable to the nearest 0.13 mm H20 (0.005 in H20) for Ap values between 1.3
and 25 mm H20 (0.05 and 1.0 in. H20), and to the nearest 1.3 mm H20
(0.05 in. H20) for Ap values above 25 mm H20 (1.0 in. H20). A special, more
sensitive gauge will be required to read Ap values below 1.3 mm H20' [0.05
in. H20](see Citation 18 in Section 6).
C-ll
-------
c=Q
o
i—•
ro
T
CURVED OR
MITERED JUNCTION
HEMISPHERICAL
TIP
Figure 2-4. Standard pitot tube design specifications.
-------
3. Procedure
3.1 Set up the apparatus as shown in Figure 2-1. Capillary
tubing or surge tanks installed between the manometer and pitot tube
may be used to dampen Ap fluctuations. It is recommended, but not
required, that a pretest leak-check be conducted, as follows: (1) blow
through the pi tot impact opening until at least 7:6 cm (3 in.)
H20 velocity pressure registers on the manometer; then, close off the
impact opening. The pressure shall remain stable for at least 15
seconds; (2) do the same for the static .pressure side, except using
suction to obtain the minimum of 7.6 cm (3 in.) H20. Other leak-check
procedures, subject to the approval of the Administrator, may be used.
3.2 Level and zero the manometer. Because the manometer level
and zero may drift due to vibrations and temperature changes, make
periodic checks during the traverse. Record all necessary data as
shown in the example data sheet (Figure 2-5).
3.3 Measure the velocity head and temperature at the traverse
points specified by Method 1. Ensure that the proper differential
pressure gauge is being used for the range of Ap values encountered
(see Section 2.2). If it is necessary to change to a more sensitive
gauge, do so, and remeasure the Ap and temperature readings at each
traverse point. Conduct a post-test leak-check (mandatory), as
described in Section 3.1 above, to validate the traverse run.
3.4 Measure the static pressure in the stack. One reading is
usually adequate.
3.5 Determine the atmospheric pressure.
3.6 Determine the stack gas dry molecular weight. For combustion
processes or processes that emit essentially C02> 02, CO, and N2> use
C-13
-------
PLANT
DATE .
RUN NO.
STACK DIAMETER OR DIMENSIONS, m(in.)
BAROMETRIC PRESSURE, mm Hg (in. Hg)_
CROSS SECTIONAL AREA. m2(ft2)
OPERATORS
PITOTTUBEI.D.NO.
AVG. COEFFICIENT, Cp =
LAST DATE CALIBRATED.
SCHEMATIC OF STACK
CROSS SECTION
Traverse
Pt.No.
mm (in.) H20
Stack Temperature
ts. °C
T. °K
mm Hg (in.Hg)
Avenge
Figure 2-5. Velocity traverse data.
C-14
-------
Method 3. For processes emitting essentially air, an analysis need
not be conducted; use a dry molecular weight of 29.0. For other processes,
other methods,-subject to the approval of the Administrator, must be used.
3.7 Obtain the moisture content from Reference Method 4 (or
equivalent.) or from Method 5.
3.8 Determine the cross-sectional area of the stack or duct at
the sampling location. Whenever possible, physically measure the stack
dimensions rather than using blueprints.
4. Calibration
4.1 Type S Pitot Tube. Before its initial use, carefully examine
the Type S pitot tube in top, side, and end views to verify that the face
openings of the tube are aligned within the specifications illustrated in
Figure 2-2 or 2-3. The pitot tube shall not be used if it fails to meet
these alignment specifications.
After verifying the face opening alignment, measure and record the
following dimensions of the pitot tube: (a) the external tubing diameter
(dimension D., Figure 2-2b); and (b) the base-to-opening plane distances
(dimensions P. and Pg, Figure 2-2b). If D. is between 0.48 and 0.95 cm
(3/16 and 3/8 in.), and if P. and P- are equal and between 1.05 and 1.50
Dt, there are two possible options: (1) the pitot tube may be cali-
brated according to the procedure outlined in Sections 4.1.2 through
4.1.5 below, or (2) a baseline (isolated tube) coefficient value of
0.84 may be assigned to the pitot tube. Note, however, that if the
pitot tube is part of an assembly, calibration may still be required,
despite knowledge of the baseline coefficient value (see Section 4.1.1).
If Dt, P., and PB are outside the specified limits, the pitot tube
must be calibrated as outlined in 4.1.2 through 4.1.5 below.
C-15
-------
4.1.1 Type S Pitot Tube Assemblies. During sample and velocity
traverses, the isolated Type S pitot tube is not always used; in many
instances, the pitot tube is used in combination with other source-
sampling components (thermocouple, sampling probe, nozzle) as part
of an "assembly." The presence of other sampling components can
sometimes affect the baseline value of the Type S pitot tube
coefficient (Citation 9 in Section 6); therefore an assigned (or
otherwise known) baseline coefficient value may or may not be valid
for a given assembly. The baseline and assembly coefficient values
will be identical only when the relative placement of the components
in the assembly is such that aerodynamic interference effects are
eliminated. Figures 2-6 through 2-8 illustrate interference-free
component arrangements for Type S pitot tubes having external tubing
diameters between 0.48 and 0.95 cm (3/16 and 3/8 in.). Type S pitot
tube assemblies that fail to meet any or all of the specifications of
Figures 2-6 through 2-8 shall be calibrated according to the procedure
outlined in Sections 4.1.2 through 4.1.5 below, and prior to calibra-
tion, the values of the intercomponent spacings (pitot-nozzle, pitot-
thermocouple, pitot-probe sheath) shall be measured and recorded.
Note: Do not use any Type S pitot tube assembly which is
constructed such that the impact pressure opening plane of the pitot
tube is below the entry plane of the nozzle (see Figure 2-6b).
4.1.2 Calibration Setup. If the Type S pitot tube is to be
calibrated, one leg of the tube shall be permanently marked A, and the
other, B. Calibration shall be done in a flow system having the follow-
ing essential design features:
4.1.2.1 The flowing gas stream must be confined to a duct of
definite cross-sectional area, either circular or rectangular. For
C-16
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TYPE SPITOT TUBE
I
> 1.90 cm (3/4 in.) FOR Dn • 1.3 cm (1/2 in.)
SAMPLING NOZZLE
A. BOTTOM VIEW; SHOWING MINIMUM PITOT-NOZZLE SEPARATION.
SAMPLING
PROBE
SAMPLING
NOZZLE
NOZZLE ENTRY
PLANE
STATIC PRESSURE
OPENING PLANE
IMPACT PRESSURE
OPENING PLANE
6.
SIDE VIEW; TO PREVENT PtTOT TUBE
FROM INTERFERING WITH GAS FLOW
STREAMLINES APPROACHING THE
NOZZLE THE IMPACT PRESSURE
OPENING PLANE OF THE PITOT TUBE
SHALL BE EVEN WITH OR ABOVE THE
NOZZLE ENTRY PLANE.
Figure 2-6. Proper pitot tube - sampling nozzle configuration to present
aerodynamic interference; buttonhook - type nozzle; centers of nozzle
and pitot opening aligned; Dt between 0.48 and 0.95 cm (3/16 and
3/8 in.).
C-17
-------
THERMOCOUPLE
Z ^5.08 cm
' (2 in.)
co
THERMOCOUPLE
1.90 cm (3/4 in.)
i,
TYPE SPITOT TUBE
OR
s
a
TYPE SPITOT TUBE
SAMPLE PROBE
SAMPLE PROBE
Figure 2-7. Proper thermocouple placement to prevent interference;
Dt between 0.48 and 0.95 cm (3/16 and 3/8 in.).
-------
o
t—•
',-0
TYPE SPITOTTUBE
SAMPLE PROBE
.62 cm (3 in.)
Figure 28. Minimum pitot sample probe separation needed to prevent interference;
Dt between 0.48 and 0.95 cm (3/16 and 3/8 in.).
-------
circular cross-sections, the minimum duct diameter shall be 30.5 cm
(12 inO; for rectangular cross-sections, the width (shorter side)
shall be at least 25.4 cm (10 in.).
4.1.2.2 The cross-sectional area of the calibration duct must
be constant over a distance of 10 or more duct diameters. For a
rectangular cross-section, use an equivalent diameter, calculated
from the following equation, to determine the number of duct diameters:
71 u
De = (L + w) Equation 2-1
where:
D - Equivalent diameter
L = Length
W = Width
To ensure the presence of stable, fully developed flow patterns
at the calibration site, or "test section," the site must be located
at least eight diameters downstream and two diameters upstream from
the nearest disturbances.
Note: The eight- and two-diameter criteria are not absolute;
other test section locations may be used (subject to approval of the
Administrator), provided that the flow at the test site is stable and
demonstrably parallel to the duct axis.
4.1.2.3 The flow system shall have the capacity to generate a
test-section velocity around 915 m/min (3000 ft/min). This velocity
i
must be constant with time to guarantee steady flow during calibration.
Note that Type S pitot tube coefficients obtained by single-velocity
calibration at 915 m/min (3000 ft/min) will generally be valid to
within +3 percent for the measurement of velocities above 305 m/min
C-20
-------
(1000 ft/min) and to within +5 to 6 percent for the measurement of
velocities between 180 and 305 m/min (600 and 1000 ft/min). If a
more precise correlation between C and velocity is desired, the flow
system shall have the capacity to generate at least four distinct,
time-invariant test-section velocities covering the velocity range
from 180 to 1525 m/min (600 to 5000 ft/min), and calibration data
shall be taken at regular velocity intervals over this range (see
Citations 9 and 14 in Section 6 for details).
4.1.2.4 Two entry ports, one each for the standard and Type S
pitot tubes, shall be cut in the test section; the standard pitot entry
port shall be located slightly downstream of the Type S port, so that
the standard and Type S impact openings will lie in the same cross-
sectional plane during calibration. To facilitate alignment of the
pitot tubes during calibration, it is advisable that the test section
be constructed of plexiglas or some other transparent material.
4.1.3 Calibration Procedure. Note that this procedure is a
general one and must not be used without first referring to the special
considerations presented in Section 4.1.5. Note also that this pro-
cedure applies only to single-velocity calibration. To obtain calibration
data for the A and B sides of the Type S pitot tube, proceed as follows:
4.1.3.1 Make sure that the manometer is properly filled and that
the oil is free from contamination and is of the proper density. Inspect
and leak-check all pitot lines; repair or replace if necessary.
4.1.3.2 Level and zero the manometer. Turn on the fan and allow
the flow to stabilize. Seal the Type S entry port.
4.1.3.3 Ensure that the manometer is level and zeroed. Position
the standard pitot tube at the calibration point (determined as outlined
C-21
-------
in Section 4.1.5.1), and align the tube so that its tip is pointed
directly into the flow. Particular care should be taken in aligning
the tube to avoid yaw and pitch angles. Make sure that the entry
port surrounding the tube is properly sealed.
4.1.3.4 Read Ap$tcj and record its value in a data table similar
to the one shown in Figure 2-9. Remove the standard pi tot tube from
the duct and disconnect it from the manometer. Seal the standard
entry port.
4.1.3.5 Connect the Type S pi tot tube to the manometer. Open
the Type S entry port. Check the manometer level and zero. Insert
and align the Type S pitot tube so that its A side impact opening is
at the same point as was the standard pi tot tube and is pointed directly
into the flow. Make sure that the entry port surrounding the tube is
properly sealed.
4.1.3.6 Read Ap and enter its value in the data table. Remove
the Type S pitot tube from the duct and disconnect it from the manometer.
4.1.3.7 Repeat steps 4.1.3.3 through 4.1.3.6 above until three
pairs of Ap readings have been obtained.
4.1.3.8 Repeat steps 4.1.3.3 through 4.1.3.7 above for the B side
of the Type S pi tot tube.
4.1.3.9 Perform calculations, as described in Section 4.1.4 below.
4.1.4 Calculations.
4.1.4.1 For each of the six pairs of Ap readings (i.e.i three
from side A and three from side B) obtained in Section 4.1.3 above,
calculate the value of the Type S pitot tube coefficient as follows:
C-22
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PITOTTUBE IDENTIFICATION NUMBER:
CALIBRATED BY:
DATE:
RUN NO.
1
2
3
"A" SIDE CALIBRATION
APstd
cm H20
(in. H20)
Ap($)
cm H20
(in. H20)
Cp (SIDE A)
cp(s)
DEVIATION
Cp(j)-Cp(A)
RUN NO.
1
2
3
"B" SIDE CALIBRATION
Ap«d
cmH20
(in. H20)
Ap($)
cmH20
(in. H20)
Cp (SIDE B)
Cp(s)
DEVIATION
Cp(5)-Cp(B)
AVERAGE DEVIATION = a (A ORB)
I |Cp(s)'Cp(A ORB)
Cp (SIDE A)-Cp (SIDE B) |-*-MUST BE <0.01
Figure 2-9. Pilot tube calibration data.
MUST BE
C-23
-------
S(s) = S(std)
where:
C / \ = Type S pi tot tube coefficient
C / o.j\ = Standard pitot tube coefficient; use 0.99 if the
p(std;
coefficient is unknown and the tube is designed
according to the criteria of Sections 2.7.1 to 2.7.5
of this method.
&p . . = Velocity head measured by the standard pitot tube,
cm H20 (in. H20)
Ap - Velocity head measured by the Type S pitot tube,
cm H20 (in. HgO)
4.1.4.2 Calculate C~ (side A), the mean A-side coefficient, and
C_ (side B), the mean B-side coefficient; calculate the difference
between these two average values.
4.1.4.3 Calculate the deviation of each of the three A-side values
of C / x from U (side A), and the deviation of each B-side value of
C / x from C~ (side B). Use the following equation:
Deviation = C / » - C~ (A or B) Equation 2-3
4.1.4.4 Calculate o, the average deviation from the mean, for
both the A and B sides of the pitot tube. Use the following equation:
lCp(s) ~S (Aor
a (side A or B) = - - = - Equation 2-4
C-24
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4.1.4.5 Use the Type S pitot tube only if the values of a
(side A) and a (side B) are less than or equal to 0.01 and if the
absolute value of the difference between C_ (A) and C" (B) is 0.01
or less.
4.1.5 Special considerations.
4.1.5.1 Selection of calibration point.
4.1.5.1.1 When an isolated Type S pitot tube is calibrated,
select a calibration point at or near the center of the duct, and
follow the procedures outlined in Sections 4.1.3 and 4.1.4 above.
The Type S pitot coefficients so obtained, i.e., C_ (side A) and
C_ (side B), will be valid, so long as either: (1) the isolated
pitot tube is used; or (2) the pitot tube is used with other com-
ponents (nozzle, thermocouple, sample probe) in an arrangement that
is free from aerodynamic interference effects (see Figures 2-6 through
2-8).
4.1.5.1.2 For Type S pitot tube-thermocouple combinations
(without sample probe), select a calibration point at or near the
center of the duct, and follow the procedures outlined in Sections
4.1.3 and 4.1.4 above. The coefficients so obtained will be valid
so long as the pitot tube-thermocouple combination is used by itself
or with other components in an interference-free arrangement (Figures
2-6 and 2-8).
4.1.5.1.3 For assemblies with sample probes, the calibration
point should be located at or near the center of the duct; however,
C-25
-------
insertion of a probe sheath into a small duct may cause significant
cross-sectional area blockage and yield incorrect coefficient
values (Citation 9 in Section 6). Therefore, to minimize the
blockage effect, the calibration point may be a few inches off-center
if necessary. The actual blockage effect will be negligible when the
theoretical blockage, as determined by a projected-area model of the
probe sheath, is 2 percent or less of the duct cross-sectional area
for assemblies without external sheaths (Figure 2-10a), and 3 percent
or less for assemblies with external sheaths (Figure 2-10b).
4.1.5.2 For those probe assemblies in which pitot tube-nozzle
interference is a factor (i.e., those in which the pitot-nozzle
separation distance fails to meet the specification illustrated in
Figure 2-6a), the value of C , » depends upon the amount of free-space
between the tube and nozzle, and therefore is a function of nozzle
size. In these instances, separate calibrations shall be performed
with each of the commonly used nozzle sizes in place. Note that the
single-velocity calibration technique is acceptable for this purpose,
even though the larger nozzle sizes (>0.635 cm or 1/4 in.) are not
ordinarily used for isokinetic sampling at velocities around
915 m/min (3000 ft/min), which is the calibration velocity; note
also that it is not necessary to draw an isokinetic sample during
calibration (see Citation 19 in Section 6).
4.1.5.3 For a probe assembly constructed such that its pitot
tube is always used in the same orientation, only one side of the
pitot tube need be calibrated (the side which will face the flow).
The pitot tube must still meet the alignment specifications of
Figure'2-2 or 2-3, however, and must have an average deviation (a)
value of 0.01 or less (see Section 4.1.4.4).
C-26
-------
(a)
(b)
ESTIMATED
SHEATH
BLOCKAGE
r t
[pUC
UCTAREA
x 100
Figure 2-10. Projected-area models for typical pitot tube assemblies.
-------
4.1.6 Field Use and Recallbration.
4.1.6.1 Field Use.
•4.1.6.1.1 When a Type S pitot tube (isolated tube or assembly) is
used in the field, the appropriate coefficient value (whether assigned
or obtained by calibration) shall be used to perform velocity calculations.
For calibrated Type S pitot tubes, the A side coefficient shall be used
when the A side of the tube faces the flow, and the B side coefficient
shall be used when the B side faces the flow; alternatively, the
arithmetic average of the A and B side coefficient values may be
used, irrespective of which side faces the flow.
4.1.6.1.2 When a probe assembly is used to sample a small duct
(12 to 36 in. in diameter), the probe sheath sometimes blocks a
significant part of the duct cross-section, causing a reduction in
the effective value of C_(s)- Consult Citation 9 in Section 6 for
details. Conventional pitot-sampling probe assemblies are not recom-
mended for use in ducts having inside diameters smaller than 12 inches
(Citation 16 in Section 6).
4.1.6.2 Recalioration.
4.1.6.2.1 Isolated Pitot Tubes. After each field use, the pitot
tube shall be carefully reexamined in top, side, and end views. If the
pitot face openings are still aligned within the specifications illus-
trated in Figure 2-2 or 2-3, it can be assumed that the baseline coef-
ficient of the pitot tube has not changed. If, however, the tube has
been damaged to the extent that it no longer meets the specifications of
Figure 2-2 or 2-3, the damage shall either be repaired to restore
proper alignment of the face openings or the tube shall be discarded.
4.1.6.2.2 Pitot Tube Assemblies. After each field use, check the
face opening alignment of the pitot tube, as in Section 4.1.6.2.1; also,
C-28
-------
remeasure the intercomponent spacings of the assembly. If the inter-
component spacings have not changed and the face opening alignment is
acceptable, it can be assumed that the coefficient of the assembly
has not changed. If the face opening alignment is no longer within the
specifications of Figures 2-2 or 2-3, either repair the damage or
replace the pitot tube (calibrating the new assembly, if necessary).
If the intercomponent spacings have changed, restore the original
spacings or recalibrate the assembly.
4.2 Standard pitot tube (if applicable). If a standard pitot tube
is used for the velocity traverse, the tube shall be constructed
according to the criteria of Section 2.7 and shall be assigned a
' baseline coefficient value of 0.99. If the standard pitot tube is
used as part of an assembly, the tube shall be in an interference-
free arrangement (subject to the approval of the Administrator).
4.3 Temperature Gauges. After each field use, calibrate dial
thermometers, liquid-filled bulb thermometers, thermocouple-
potentiometer systems, and other gauges at a temperature within
10 percent of the average absolute stack temperature. For temperatures
up to 405°C (761°F), use an ASTM mercury-in-glass reference thermometer,
or equivalent, as a reference; alternatively, either a reference
thermocouple and potentiometer (.calibrated by NBS) or thermometric
fixed points, e.g., ice bath and boiling water (corrected for barometric
pressure) may be used. For temperatures above 405°C (761°F), use an
NBS-calibrated reference thermocouple-potentiometer system or an
alternate reference, subject to the approval of the Administrator.
If, during calibration, the absolute temperatures measured with
the gauge being calibrated and the reference gauge agree within 1.5
percent, the temperature data taken in the field shall be considered
valid. Otherwise, the pollutant emission test shall either be
C-29
-------
considered invalid or adjustments (if appropriate) of the test results
shall be made, subject to the approval of the Administrator.
4.4 Barometer. Calibrate the barometer used against a mercury
barometer.
5. Calculations
Carry out calculations, retaining at least one extra decimal
figure beyond that of the acquired data. Round off figures after
final calculation.
5.1 Nomenclature.
2 2
A = Cross-sectional area of stack, m (ft ).
B = Water vapor in the gas stream (from Method 5 or Reference
W5
Method 4), proportion by volume.
C = Pitot tube coefficient, dimensionless.
P
K = Pitot tube constant,
m gg-moleHmm Hg) '
)|
J
<> sec L (K)(mm H20)
for the metric system and
RC AQ _ft [(Ib/lb-moleUin. Hgfl 1/2
°°*Hy sec [ (°R)(in. H20) J
for the English system.
M. = Molecular weight of stack gas, dry basis (see Section 3.6)
g/g-mole (Ib/lb-mole).
M = Molecular weight of stack gas, wet basis, g/g-mole
(Ib/lb-mole).
= Md(l - Bws) + 18.0 Bws Equation 2-5
P. = Barometric pressure at measurement site, mm Hg (in. Hg).
P = Stack static pressure, mm Hg (in. Hg).
C-30
-------
P = Absolute stack gas pressure, mm Hg (in. Hg).
s
w~. + P Equation 2-6
bar
P td = Standard absolute pressure, 760 mm Hg (29.92 in. Hg).
Q . = Dry volumetric stack gas flow rate corrected to standard
*
conditions, dscm/hr (dscf/hr).
t = Stack temperature, °C (°F).
T = Absolute stack temperature, °K (°R).
= 273 + t for metric Equation 2-7
= 460 + ts for English Equation 2-8
T t(j = Standard absolute temperature, 293 °K (528°R).
v = Average stack gas velocity, m/sec (ft/sec).
Ap = Velocity head of stack gas, mm H20 (in. H20).
3600 = Conversion factor, sec/hr.
18.0 = Molecular weight of water, g/g-mole (Ib/lb-mole).
5.2 Average stack gas velocity.
Equation 2-9
5.3 Average stack gas dry volumetric flow rate.
Qsd - 3600 (L^, vsA Equation 2-,0
6. Bibliography
1. Mark, L. S. Mechanical Engineers' Handbook. New York.
McGraw-Hill Book Co., Inc. 1951.
2. Perry, 0. H. Chemical Engineers' Handbook. New York
McGraw-Hill Book Co., Inc. 1960.
C-31
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3. Shigehara, R. T., W. F. Todd, and W. S. Smith. Significance
of Errors in Stack Sampling Measurements. U. S. Environmental
Protection Agency, Research Triangle Park, N. C. (Presented at the
Annual Meeting of the Air Pollution Control Association, St. Louis, Mo.,
June 14-19, 1970.)
4. Standard Method for Sampling Stacks for Particulate Matter.
In: 1971 Book of ASTM Standards, Part 23. Philadelphia, Pa. 1971.
ASTM Designation D-2928-71.
5. Vennard, J. K. Elementary Fluid Mechanics. New York.
John Wiley and Sons, Inc. 1947.
6. Fluid Meters - Their Theory and Application. American Society
of Mechanical Engineers, New York, N.Y. 1959.
7. ASHRAE Handbook of Fundamentals. 1972. p. 208.
8. Annual Book of ASTM Standards, Part 26. 1974. p. 648.
9. Vollaro, R. F. Guidelines for Type S Pitot Tube Calibration.
U. S. Environmental Protection Agency, Research Triangle Park, N. C.
(Presented at 1st Annual Meeting, Source Evaluation Society, Dayton, Ohio,
September 18, 1975.)
10. Vollaro, R. F. A Type S Pitot Tube Calibration Study. U. S.
Environmental Protection Agency, Emission Measurement Branch, Research
Triangle Park, N. C. July 1974.
11. Vollaro, R. F. The Effects of Impact Opening Misalignment on
the Value of the Type S Pitot Tube Coefficient. U. S. Environmental
Protection Agency, Emission Measurement Branch, Research Triangle Park,
N. C. October 1976.
C-32
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12. Vollaro, R. F. Establishment of a Baseline Coefficient Value
for Properly Constructed Type S Pitot Tubes. U. S. Environmental
Protection Agency, Emission Measurement Branch, Research Triangle
Park, N. C. November 1976.
13. Vollaro, R. F. An Evaluation of Single-Velocity Calibration
Technique as a Means of Determining Type S Pi tot Tube Coefficients.
U. S. Environmental Protection Agency, Emission Measurement Branch,
Research Triangle Park, N. C. August 1975.
14. Vollaro, R. F. The Use of Type S Pi tot Tubes for the Measurement
of Low Velocities. U. S. Environmental Protection Agency, Emission
Measurement Branch, Research Triangle Park, N. C. November 1976.
15. Smith, Marvin L. Velocity Calibration of EPA Type Source
Sampling Probe. United Technologies Corporation, Pratt and Whitney
Aircraft Division, East Hartford, Conn. 1975.
16. Vollaro, R. F. Recommended Procedure for Sample Traverses in
Ducts Smaller than 12 Inches in Diameter. U. S. Environmental Protection
Agency, Emission Measurement Branch, Research Triangle Park, N. C.
November 1976.
17. Ower, E. and R. C. Pankhurst. The Measurement of Air Flow,
4th Ed. London, Pergamon Press. 1966.
18. Vollaro, R. F. A Survey of Commercially Available Instrumentation
for the Measurement of Low-Range Gas Velocities. U. S. Environmental
Protection Agency, Emission Measurement Branch, Research Triangle Park,
N. C. November 1976. (Unpublished Paper)
C-33
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19. Gnyp, A. W., C. C. St. Pierre, D. S. Smith, D. Mozzon, and
J. Steiner. An'Experimental Investigation of the Effect of Pitot Tube-
Sampling Probe Configurations on the Magnitude of the S Type Pi tot Tube
Coefficient for Commercially Available Source Sampling Probes. Prepared
by the University of Windsor for the Ministry of the Environment,
Toronto, Canada. February 1976.
C-34
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SLIDE 103-0
METHOD — 2
Determination of Stack Gas Velocity
and Volumetric Flow Rate
NOTES
SLIDE 103-1
C-35
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SLIDE 103-2
TYPE S PTFOT TUBE MANOMETER ASSEMBLY
NOTES
FLEXIBLE TUBING
625MMIV.INI
L = DISTANCE TO FURTHEST SAMPLING
POINT PIUS 30 CM (12 IN I
•PITOT TUBE — TEMPERATURE SENSOR SPACING
SLIDE 103-3
APPLICABILITY OF METHOD 2
This method is only applicable at sites which:
1. Meet the criteria of method 1
2. Do not contain cyclonic or non parallel tlow
ALTERNATIVES WHEN UNACCEPTABLE
CONDITIONS EXIST
(Subject to Approval of the Administrator)
1. Install straightening vanes.
2. Calculate total volumetric flow rate
stoichiometrically.
3. Move to a measurement site at which flow is
acceptable.
4. Use procedures as described in the cyclonic
flow special problems session.
C-37
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SLIDE 103-4
NOTES
SLIDE 103-5
DIFFERENTIAL PRESSURE GAUGE
An inclined manometer or equivalent device is required
to measure AR
A differential pressure gauge of greater sensitivity shall
be used if any of the following conditions exist:
1. arithmetic average of all AP readings is < 0.05 in. \-\2O
2. traverses of > 12 pts., and 10% of AP readings are below
0.05 in. H2O
3. traverses of < 12 pts., and more than 1 ^P reading is
below 0.05 in. H2O
Note: Standard manometer used in source testing is a 10 in.
inclined vertical manometer (0.01 in. divisions on a 0 to
1 in. scale, and 0.1 in. divisions on a 1 to 10 in. scale).
C-39
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SLIDE 103-6 NOTES
(cont.)
• Alternative approach to determine if a more sensitive
differential pressure guage is required:
S 1/AP, + K
If T is > 1.05, a more sensitive differential pressure
guage must be used.
Where:
AP, = individual velocity head reading at a traverse
point
n = total number of points
K = 0.13 mm H2O for metric units and 0.005 in.
H2O for English units
SLIDE 103-7
TEMPERATURE SENSOR
The temperature sensor must be accurate to within
1.5% of Minimum Absolute Stack Temperature.
Temperature sensors typically used in testing include:
• Thermocouple
• Bimetallic Thermometer
• Mercury-in-Glass Thermometer
• Liquid-Filled Bulb Thermometer
Note: When the stack temperature measurement is used to
calculate moisture, the sensitivity is ± 2°F.
C-41
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SLIDE 103-8
NOTES
SLIDE 103-9
PRESSURE PROBE AND GUAGE
Static pressure measurement must be accurate to
within 0.1 in. Hg (1.36 in. H:O).
Pressure sensors typically used to measure static
pressure during testing include:
• a piezometer tube and mercury or water-filled U-tube
manometer
• the static tap of a standard pitot tube
• one leg of the type S pitot tube
C-43
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SLIDE 103-10 NOTES
BAROMETRIC PRESSURE
Barometric pressure measurement must be accurate
to within 0.1 in. Hg.
Barometric pressure during testing is obtained by:
INSTRUMENT
Mercury, aneroid or other barometer (with required
sensitivity)
OTHER
Obtain barometric pressure from nearby National
Weather Service station (station pressure) and adjust
for elevation differences between sampling site and
weather station.
Note: The station pressure must be used not the
pressure corrected to sea level.
SLIDE 103-11
PITOT TUBE CALIBRATION
Perform Dimensional Specification Test
and/or
Calibrate in wind tunnel against standard pitot
tube (preferably with NBS traceable coefficient)
C-45
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SLIDE 103-12
NOTES
SLIDE 103-13
C-47
-------
SLIDE 103-14
NOTES
SLIDE 103-15
C-49
-------
SLIDE 103-16
NOTES
SLIDE 103-17
C-51
-------
SLIDE 103-18
NOTES
SLIDE 103-19
C-53
-------
SLIDE 103-20
NOTES
SLIDE 103-21
C-55
-------
SLIDE 103-22
NOTES
TYPE-S PITOT TUBE INSPECTION DATA SHEET
PITOT TUBE ASSEMBLY LEVEL? .
YES.
. YES (EXPLAIN BELOW).
PITOT TUBE OPENINGS DAMAGED?
», = M 10°), „, = °KIO°), p, = °(-5u
-y = °. < > = !. A = CM (IN.)
z = A sin y = CM (IN.); 0.32 CM Ktt IN.).
w = AsinO = CM (IIM.I; 0.08 CM KVulN.)
P. CM (IN.) Pb CM (IN.)
NO
.NO
s°i
.CM (IN.I _t_ =
.(1.05 - and - 1.50)
COMMENTS:
CALIBRATION REQUIRED? .
DATE:
-CONDUCTED BY:
SLIDE 103-23
"S" Typ
Fliot Tube
V (8 Oiams
C-57
-------
SLIDE 103-24
NOTES
PITOT TUBE CALIBRATION DATA SHEET
CALIBRATION PITOT TUBE: TYPE STD. SIZE (OD) JV. ID NUMBER _2_
TYPE S PITOT TUBE ID NUMBER 8S €„,,,,,, = 1.0
CALIBRATION: DATE 3/10/76 PERFORMED
"A" SIDE CALIBRATION
AP.UJ
cmH,O
(IN. HZ0)
0.20
1 0.30
0.50
1.00
!
Ap,
cm HjO
(IN. H20)
0.28
0.41
0.69
1.38
AVERAGE
\a
Cp(SI
0.845
0.856
0.851
0.850
0.850
\b
DEV.
-0.005
0.006
-0.001
0
= Cp(mtd,
b DEV = Cpjs, = Cp, (MUST BE sO.01).
Cp(A) = Cp(B) = 0.005 (MUST BE sO.01).
= 1.0 /0.714 = 0.845
SLIDE 103-25
DIFFERENTIAL PRESSURE GAUGE CALIBRATION
TO PRESSURE SOURCE OR
VENTED TO ATMOSPHERE
TO VACUUM SYSTEM OR
VENTED TO ATMOSPHERE
C-59
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SLIDE 103-26
NOTES
TEMPERATURE SENSOR CALIBRATION
Calibrate initially and after each field use.
Post test calibration must be performed at a temperature
within 10% of the average absolute stack temperature.
CALIBRATION REFERENCES
UP TO 761°F ABOVE 761°F
ASTM Mercury-in-glass NBS-Calibrated reference
reference thermometer thermocouple
ALTERNATIVE CALIBRATION REFERENCES
Thermometric fixed points (ice bath and boiling water)
SLIDE 103-27
C-61
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SLIDE 103-28
NOTES
SLIDE 103-29
TEMPERATURE SENSOR CALIBRATION
EVALUATION
THERMOCOUPLE
Absolute temperature values must agree within
± 1.5% at each point.
• Plot data on linear graph paper, draw best fit line.
• Data may be extrapolated above and below calibration
points.
THERMOMETER
Absolute temperature values must agree within
+ 1.5% at each point.
• Thermometer may be used over the range of calibration
points.
• If correction factor is needed it must be affixed to
thermometer.
C-63
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SLIDE 103-30
NOTES
SLIDE 103-31
C-65
-------
SLIDE 103-32
NOTES
SLIDE 103-33
VELOCITY MEASUREMENT PROCEDURES
1. Leak-check pilot tube and differential pressure gauge.
2. For circular stacks less than 10 ft. in diameter, two ports
are sufficient. Use four ports when stack diameter is
greater than 10ft.
3. Pilot tubes longer than 10 ft. should be structurally
reinforced to prevent bending of tube and misalign-
ment errors.
4. Identify each sample port and traverse point with a
letter or number.
5. Read velocity head and temperature at least twice at
each point and record the average.
C-67
-------
SLIDE 103-34
(conL)
6. Care should be taken to prevent touching the pitot
tube tip to the side of the stack.
7. Plug unused sampling ports and seal port being used
as tightly as possible.
8. After traverse, check differential pressure gauge zero;
repeat traverse if zero has shifted.
9. If liquid droplets are present, use a liquid trap in
positive pressure leg of pitot tube.
10. A post-test leak check is required after each run of the
pitot tube and velocity pressure system.
NOTES
SLIDE 103-35
STATIC PRESSURE MEASUREMENT
PRESSURE PROBE AND GAUGE
STANDARD PITOT TUBE
TYPE S PITOT TUBE
MANOMETER
MANOMETER
MANOMETER
C-69
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SECTION D. METHOD 3
Subject Page
1. Method 3--gas analysis for carbon dioxide, oxygen, excess air,
and dry molecular weight (taken from Environmental Protection
Agency Performance Test Methods manual) D-3
2. Slides D-19
D-l
-------
METHOD 3--GAS ANALYSIS FOR CARBON DIOXIDE, OXYGEN,
EXCESS AIR, AND DRY MOLECULAR WEIGHT
1. Principle and Applicability
1.1 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) multi-point, integrated sampling.
The gas sample is analyzed for percent carbon dioxide (C0?), percent
oxygen (Og), and, if necessary, percent carbon monoxide (CO). If a
dry molecular weight determination is to be made, either an Orsat
or a Fyrite analyzer may be used for the analysis; for excess air
or emission rate correction factor determination, an Orsat analyzer
must be used.
1.2 Applicability. This method is applicable for determining
C02 and 0« concentrations, excess air, 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 C02, 02, CO, and nitrogen (N-)
are not present in concentrations sufficient to affect the results.
Other methods, as well as modifications to the procedure
described herein, are also applicable for some or all of the above
determinations. Examples of specific methods and modifications
include: (1) a multi-point sampling method using an Orsat analyzer
to analyze individual grab samples obtained at each point; (2) a
method using C02 or 0« and stoichiometric calculations to determine
dry molecular weight and excess air; (3) assigning a value of 30.0
Mention of trade names or specific products does not constitute
endorsement by the Environmental Protection Agency.
D-3
-------
for dry molecular weight, in lieu of actual measurements, for
processes burnjng 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.
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. The probe should be made of stainless steel or
borosilicate glass tubing and should be 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 material inert to
02» CCL, CO, and N2 and resistant to temperature at sampling conditions
may be used for the probe; examples of such material are aluminum,
copper, quartz glass and Teflon.
2.1.2 Pump. A one-way squeeze bulb, or equivalent, is used
to transport the gas sample to the analyzer.
2.2 Integrated Sampling (Figure 3-2).
2.2.1 Probe. A probe such as that described in Section 2.1.1
is suitable.
D-4
-------
PROBE
FLEXIBLE TUBING
\
FILTER (GLASS WOOL)
SQUEEZE BULB
TO ANALYZER
Figure 3-1. Grab-sampling tram.
RATE METER
AIR-COOLED
CONDENSER
\
FILTER
(GLASS WOOL)
QUICK DISCONNECT
_n
RIGID CONTAINER
Figure 32. Integrated gas sampling train.
D-5
-------
2.2.2 Condenser. An air-cooled or water-cooled condenser,
or other condenser that will not remove 02, C02, CO, and N2, may
be used to.remove excess moisture which would interfere with
the operation of the pump and flow meter.
2.2.3 Valve. A needle valve is used to adjust sample gas
flow rate.
2.2.4 Pump. A leak-free, diaphragm-type pump, or equivalent,
is used 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. The rotameter, or equivalent rate meter,
used should be capable of measuring flow rate to within +2 percent
of the selected flow rate. A flow rate range of 500 to 1000
cm /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, may be used. A
capacity in the range of 55 to 90 liters is suggested.
To leak-check the bag, connect it to a water manometer and pressurize
the bag to 5 to 10 cm H20 (2 to 4 in. H20). 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 H20 (2 to 4 in. HgO) and allow to stand overnight. A
deflated bag indicates a leak.
D-6
-------
2.2.7 Pressure Gauge. A water-filled U-tube manometer, or
equivalent, of about 28 cm (12 in.) is used for the flexible bag
leak-check.
2.2.8 Vacuum Gauge. A mercury manometer, or equivalent, of at
least 760 mm Hg (30 in. Hg) is used for the sampling train leak-check.
2.3 Analysis. For Orsat and Fyrite analyzer maintenance and
operation procedures, follow the instructions recommended by the
manufacturer, unless otherwise specified herein.
2.3.1 Dry Molecular Weight Determination. An Orsat analyzer or
Fyrite type combustion gas analyzer may be used.
2.3.2 Emission Rate Correction Factor or Excess Air Determination.
An Orsat analyzer must be used. For low C02 (less than 4.0 percent)
or high 02 (greater than 15.0 percent) concentrations, the measuring
burette of the Orsat must have at least 0.1 percent subdivisions.
3. Dry Molecular Weight Determination
Any of the three sampling and analytical procedures described
below may be used for determining the dry molecular weight.
3.1 Single-Point, Grab Sampling and Analytical Procedure.
3.1.1 The sampling point in the duct shall either 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.
3.1.2 Set up the equipment as shown in Figure 3-1, making sure
all connections ahead of the analyzer are tight and leak-free. If an
Orsat analyzer is used, it is recommended that the analyzer be leak-
checked by following the procedure in Section 5; however, the leak-
check is optional.
D-7
-------
3.1.3 Place the probe in the stack, with the tip of the probe
positioned at the sampling point; purge the sampling line. Draw a
sample into the analyzer and immediately analyze it for percent CCL
and percent CL. Determine the percentage of the gas that is N« and
CO by subtracting the sum of the percent CCL and percent CL from
100 percent. Calculate the dry molecular weight as indicated in
Section 6.3.
3.1.4 Repeat the sampling, analysis, and calculation procedures,
until the dry molecular weights of any three grab samples differ from
their mean by.no more than 0.3 g/g-mole (0.3 Ib/lb-mole). Average
these three molecular weights, and report the results to the nearest
0.1 g/g-mole (Ib/lb-mole).
3.2 Single-Point, Integrated Sampling and Analytical Procedure.
3.2.1 The sampling point in the duct shall be located as speci-
fied in Section 3.1.1.
3.2.2 Leak-check (optional) the flexible bag as in Section 2.2.6.
Set up the equipment as shown in Figure 3-2. Just prior to sampling,
leak-check (optional) the train by placing a vacuum gauge at the
condenser inlet, pulling a vacuum of at least 250 mm Hg (10 in. Hg),
plugging the outlet at the quick disconnect, and then turning off the
pump. The vacuum should remain stable for at least 0.5 minute.
Evacuate the flexible bag. Connect the probe and place it in the
stack, with the tip of the probe positioned at the sampling point;
purge the sampling line. Next, connect the bag and make sure that
all connections are tight and leak free.
D-8
-------
3.2.3 Sample at a constant rate. The sampling run should be
simultaneous with, and for the same total length of time as, the
pollutant emission rate determination. Collection of at least 30
o
liters (1.00 ft ) of sample gas is recommended; however, smaller
volumes may be collected, if desired.
3.2.4 Obtain one integrated flue gas sample during each pollutant
emission rate determination. Within 8 hours after"the sample is taken,
analyze it for percent C02 and percent 02 using either an Orsat
analyzer or a Fyrite type combustion gas analyzer. If an Orsat
analyzer is used, it is recommended that the Orsat leak-check
described in Section 5 be performed before this determination;
however, the check is optional. Determine the percentage of the
gas that is N2 and CO by subtracting the sum of the percent C02 and
percent 02 from 100 percent. Calculate the dry molecular weight as
indicated in Section 6.3.
3.2.5 Repeat the analysis and calculation procedures until the
individual dry molecular weights for any three analyses differ from
their mean by no more than 0.3 g/g-mole (0.3 Ib/lb-mole). Average
these three molecular weights, and report the results to the nearest
0.1 g/g-mole (0.1 Ib/lb-mole).
3.3. Multi-Point, Integrated Sampling and Analytical Procedure.
3.3.1 Unless otherwise specified by the Administrator, EPA, a
minimum of eight traverse points shall be used for circular stacks having
diameters less than 0.61 m (24 in.), a minimum of nine shall be used for
rectangular stacks having equivalent diameters less than 0.61 m (24 in.),
and a minimum of twelve traverse points shall be used for all other
cases. The traverse points shall be located according to Method 1. The
use of fewer points is subject to the approval of the Administrator.
D-9
-------
3.3.2 Follow the procedures outlined in Sections 3.2.2
through 3,2.5, except for the following: traverse all sampling
points and sample at each point for an equal length of time.
Record sampling data as shown in Figure 3-3.
4. Emission Rate Correction Factor or Excess Air Determination
Note: A Fyrite type combustion gas analyzer is not acceptable
for excess air or emission rate correction factor determination,
unless approved by the Administrator. If both percent C0« and
percent (L are measured, the analytical results of any of the three
procedures given below may also be used for calculating the dry
molecular weight.
Each of the three procedures below shall be used only when
specified in an applicable subpart of the standards. The use of
these procedures for other purposes must have specific prior approval
of the Administrator.
4.1 Single-Point, Grab Sampling and Analytical Procedure.
4.1.1 The sampling point in the duct shall either 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,
4.1.2 Set up the equipment as shown in Figure 3-1, making sure
all connections ahead of the analyzer are tight and leak-free. Leak-
check the Orsat analyzer according to the procedure described in
Section 5. This leak-check 1s mandatory.
4.1.3 Place the probe in the stack, with the tip of the probe
positioned at the sampling point; purge the sampling line. Draw
D-10
-------
TIME
TRAVERSE
FT.
AVERAGE
Q
1pm
% DEV.a
a%DEV= (1JL?I9)100 (MUSTBE<10%)
Figure 3-3. Sampling rate data.
D-ll
-------
a sample into the analyzer. For emission rate correction factor
determination, immediately analyze the sample, as outlined in Sections
4.1.4 and 4.1.5, for percent C02 or percent 02. If excess air is
desired, proceed as follows: (1) immediately analyze the sample, as in
Sections 4.1.4 and 4.1.5, for percent C02, 02> and CO; (2) determine the
percentage of the gas that is N2 by subtracting the sum of the percent
C02, percent 02, and percent CO from 100 percent; and (3) calculate
percent excess air as outlined in Section 6.2.
4.1.4 To ensure complete absorption of the C0«> Op, or if appli-
cable, CO, make repeated passes through each absorbing solution until
two consecutive readings are the same. Several passes (three or four)
should be made between readings. (If constant readings cannot be
obtained after three consecutive readings, replace the absorbing solution.)
4.1.5 After the analysis is completed, leak-check (mandatory)
the Orsat analyzer once again, as described in Section 5. For the
results of the analysis to be valid, the Orsat analyzer must pass
this leak test before and after the analysis. Note: Since this
single-point, grab sampling and analytical procedure is normally
conducted in conjunction with a single-point, grab sampling and
analytical procedure for a pollutant, only one analysis is ordinarily
conducted. Therefore, great care must be taken to obtain a valid
sample and analysis. Although in most cases only C02 or 02 is
required, it is recommended that both C02 and 02 be measured, and
that Citation 5 in the Bibliography be used to validate the analytical
data.
D-12
-------
4.2 Single-Point, Integrated Sampling and Analytical Procedure.
4.2.1 The sampling point in the duct shall be located as
specified in Section 4.1.1.
4.2.2 Leak-check (mandatory) the flexible bag as in Section 2.2.6.
Set up the equipment as shown in Figure 3-2. Just prior to sampling,
leak-check (mandatory) the train by placing a vacuum gauge at the
condenser inlet, pulling a vacuum of at least 250 mm Hg (10 in. Hg),
plugging the outlet at the quick disconnect, and then turning off the
pump. The vacuum shall remain stable for at least 0.5 minute.
Evacuate the flexible bag. Connect the probe and place it in the
stack, with the tip of the probe positioned at the sampling point;
purge the sampling line. Next, connect the bag and make sure that all
connections are tight and leak free.
4.2.3 Sample at a constant rate, or as specified by the
Administrator. The sampling run must be simultaneous with, and for
the same total length of time as, the pollutant emission rate
determination. Collect at least 30 liters (1.00 ft ) of sample
gas. Smaller volumes may be collected, subject to approval of the
Administrator.
4.2.4 Obtain one integrated flue gas sample during each pollutant
emission rate determination. For emission rate correction factor
determination, analyze the sample within 4 hours after it is taken
for percent CCL or percent Op (as outlined in Sections 4.2.5 through
4.2.7). The Orsat analyzer must be leak-checked (see Section 5) before
the analysis. If excess air is desired, proceed as follows: (1) within
4 hours after the sample is taken, analyze it (as in Sections 4.2.5
D-13
-------
through 4.2.7) for percent C02» 02, and CO; (2) determine the percentage
of the gas that is Np by subtracting the sum of the percent C02, percent
02, and percent CO from TOO percent; (3) calculate percent excess air,
as outlined in Section 6.2.
4.2.5 To ensure complete absorption of the C02> 02, or if applicable,
CO, make repeated passes through each absorbing solution until two
consecutive readings are the same. Several passes (three or four)
should be made between readings. (If constant readings cannot be obtained
after three consecutive readings, replace the absorbing solution.)
4.2.6 Repeat the analysis until the following criteria are met:
4.2.6.1 For percent C02, repeat the analytical procedure until the
results of any three analyses differ by no more than (a) 0.3 percent by
volume when C02 is greater than 4.0 percent or (b) 0.2 percent by volume
when C02 is less than or equal to 4.0 percent. Average the three acceptable
values of percent C02 and report the results tu the nearest 0.1 percent.
4.2.6.2 For percent 02, repeat the analytical procedure until the
results of any three analyses differ by no more than (a) 0.3 percent by
volume when 02 is less than 15.0 percent or (b) 0.2 percent by volume
when 02 is greater than or equal to 15.0 percent. Average the three
acceptable values of percent 02 and report the results to the nearest
0.1 percent.
4.2.6.3 For percent CO, repeat the analytical procedure until the
results of any three analyses differ by no more than 0.3 percent.
Average the th^ee acceptable values of percent CO and report the results
to the nearest 0.1 percent.
D-14
-------
4.2.7 After the analysis is completed, leak-check (mandatory)
the Orsat analyzer once again, as described in Section 5. For the
results of the analysis to be valid, the Orsat analyzer must pass
this leak test before and after the analysis. Note: Although in
most instances only CCL or 02 is required, it is recommended that
both C02 and 02 be measured, and that Citation 5 in the Bibliography
be used to validate the analytical data.
4.3 Multi-Point, Integrated Sampling and Analytical Procedure.
4.3.1 Both the minimum number of sampling points and the
sampling point location shall be as specified in Section 3.3.1 of
this method. The use of fewer points than specified is subject to
the approval of the Administrator.
4.3.2 Follow the procedures outlined in Sections 4.2.2 through
4.2.7, except for the following: Traverse all sampling points and
sample at each point for an equal length of time. Record sampling
data as shown in Figure 3-3.
5. Leak-Check Procedure for Orsat Analyzers
Moving an Orsat analyzer frequently causes it to leak. Therefore,
an Orsat analyzer should be thoroughly leak-checked on site before the
flue gas sample is introduced into it. The procedure for leak-checking
an Orsat analyzer is:
5.1.1 Bring the liquid level in each pipette up to the reference
mark on the capillary tubing and then close the pipette stopcock.
5.1.2 Raise the leveling bulb sufficiently to bring the confining
liquid meniscus onto the graduated portion of the burette and then
close the manifold stopcock.
D-15
-------
5.1.3 Record the meniscus position.
5.1.4 Observe the meniscus in the burette and the liquid level
in the pipette for movement over the next 4 minutes.
5.1.5 For the Orsat analyzer to pass the leak-check, two
conditions must be met:
5.1.5.1 The liquid level in each pipette must not fall below
the bottom of the capillary tubing during this 4-minute interval.
5.1.5.2 The meniscus in the burette must not change by more
than 0.2 ml during this 4-minute interval.
5.1.6 If the analyzer fails the leak-check procedure, all
rubber connections and stopcocks should be checked until the cause
of the leak is identified. Leaking stopcocks must be disassembled,
cleaned, and regreased. Leaking rubber connections must be replaced,
After the analyzer is reassembled, the leak-check procedure must be
repeated.
6. Calculations
6.1 Nomenclature.
M. = Dry molecular weight, g/g-mole (Ib/lb-mole).
%EA - Percent excess air.
XC02 « Percent C02 by volume (dry basis).
%0« = Percent 0« by volume (dry basis).
%CO = Percent CO by volume (dry basis)-
%N2 = Percent N~ by volume (dry basis)'
0.264 = Ratio of 02 to N2 in air, v/v.
D-16
-------
0.280 = Molecular weight of Np or CO, divided by 100.
0.320 = Molecular weight of 02 divided by 100.
0.440 = Molecular weight of COp divided by 100.
6.2 Percent Excess Air. Calculate the percent excess air (if
applicable), by substituting the appropriate values of percent 02»
CO, and N2 (obtained from Section 4.1.3 or 4.2.4) into Equation 3-1.
%EA =
%Q2 - 0.5% CO
100 Equation 3-1
0.264 %N2 - (%02 - 0.5% CO)
^» ^Hl
Note: The equation above assumes that ambient air is used as
the source of 02 and that the fuel does not contain appreciable
amounts of N2 (as do coke oven or blast furnace gases). For those
cases when appreciable amounts of N2 are present (coal, oil, and
natural gas do not contain appreciable amounts of N2) or when oxygen
enrichment is used, alternate methods, subject to approval of the
Administrator, are required.
6.3 Dry Molecular Weight. Use Equation 3-2 to calculate the
dry molecular weight of the stack gas.
Md = 0.440(%C02) + 0.320(%02) + 0.280(%N2 + %CO) Equation 3-2
Note: The above equation does not consider argon in air (about
0.9 percent, molecular weight of 37.7). A negative error of about
0.4 percent is introduced. The tester may opt to include argon in
the analysis using procedures subject to approval of the Administrator.
D-17
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7. Bibliography
1. Altshuller, A.P. Storage of Gases and Vapors in Plastic
Bags. International Journal of Air and Water Pollution. 6;75-81.
1963.
2. Conner, William D. and J. S. Nader. Air Sampling with Plastic
Bags. Journal of the American Industrial Hygiene 'Association.
25_:291-297. 1964.
3. Burrell Manual for Gas Analysts, Seventh edition. Burrell
Corporation, 2223 Fifth Avenue, Pittsburgh, Pa. 15219. 1951.
4. Mitchell, W.J. and M.R. Midgett. Field Reliability of the
Orsat Analyzer. Journal of Air Pollution Control Association.
26:491-495. May 1976.
5. Shlgehara, R.T., R.M. Neulicht, and W.S. Smith. Validating
Orsat Analysis Data from Fossil Fuel-Fired Units. Stack Sampling
News. 4_(2):21-26. August, 1976.
D-18
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SLIDE 104-0 NOTES
METHOD — 3
Gas Analysts for
Carbon Dioxide, Excess Air and
Dry Molecular Weight
SLIDE 104-1
EPA METHOD 3
PRINCIPLE
A gas sample is collected by one of the following methods:
• Single-point grab sampling
• Single-point integrated sampling
• Multi-point integrated sampling
The sample is analyzed for the following components:
• Carbon dioxide (CO2)
• Oxygen (62)
• Carbon monoxide (CO) (if necessary)
APPLICABILITY
This method is applicable for determining dry molecular
weight and excess air correction factor from fossil-fuel
combustion sources.
SLIDE 104-2
GRAB SAMPLING TRAIN
FILTER
(GLASS WOOL)
FLEXIBLE TUBING
. TO ANALYZER
SQUEEZE BULB
D-19
-------
SLIDE 104-3
NOTES
SLIDE 104-4
INTEGRATED GAS SAMPLING TRAIN
FILTER
(GLASS WOOLI
RIGID CONTAINER
D-21
-------
SLIDE 104-5
NOTES
SLIDE 104-6
D-23
-------
SLIDE 104-7
NOTES
ORSAT ANALYZER
SAMPLE
INLET
THREE-WAY INLET VALVE TO MANIFOLD
INLET VALVE TO CO PIPETTE
INLET VALVE TO O, PIPETTE
INLET VALVE TO CO, PIPETTE
MANIFOLD
VOLUME
REFERENCE
MARK
WATER
JACKET
SIDE VIEW OF TYPICAL
PIPETTE ABSORBER
SLIDE 104-8
ORSAT ANALYZER REAGENTS
GAS CONFINING SOLUTION
• A solution containing sodium sulfate, sulfuric acid and
methyl orange
CARBON DIOXIDE ABSORBENT
• A solution of potassium or sodium hydroxide
OXYGEN ABSORBENT
• A solution of alkaline pyrogallic acid or chromous
chloride
CARBON MONOXIDE ABSORBENT
• A solution of cuprous chloride or a sulfate solution
D-25
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SLIDE 104-9
NOTES
FYRITE ANALYZER
SLIDE 104-10
D-27
-------
SLIDE 104-11
NOTES
SLIDE 104-12
CALIBRATION OF ANALYZERS
AMBIENT AIR CHECK (O2 reagent only)
The average of 3 replicates should be 20.8 ± 0.7%.
• a measured average value > 21.5% indicates poor
operator technique
• a measured average value < 20.1% indicates a
faulty analyzer and/or poor technique
CALIBRATION GAS CHECK
The average of 3 replicates should be + 0.5% of the
known concentration of each gas.
• high measured values indicate poor technique
• low values indicate faulty analyzer and/or poor
technique
D-29
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SLIDE 104-13
ROTAMETER CAUBRAT1ON CURVE
NOTES
0.5 l.o
SAMPLING RATE. I/mm at 21"C and 760 mm Hg
SLIDE 104-14
SAMPLING METHODS
Single-Point Grab Sampling
1. Sample point should be a centriod of the cross section or
at a point 3.28 ft. from the walls of a large stack.
2. Place probe securely in stack and seal sampling port to
prevent dilution of stack gas.
3. Purge sample line and attach to analyzer.
4. Aspirate sample into analyzer.
SLIDE 104-15
SAMPLING METHODS
Single-Point Integrated Sampling
1. Sample point and probe placement is same as for single-
point grab sampling.
2. Leak-check the flexible bag.
3. Leak-check the sampling train.
4. Connect probe to train and purge the system.
5. Connect evacuated flexible bag and begin sampling.
6. Sample at constant rate; collect 30 to 90 liters of gas
simultaneous with pollutant emission test.
D-31
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S-LIDE 104-16
NOTES
SAMPLING METHODS
Multi-Point Integrated Sampling
1. This procedure uses same sample train and equipment pre-
paration as the single-point integrated sampling method.
2. Locate sampling points according to method 1.
3. Sample each point at the same rate and for the same time
increment.
4. Collect 30 to 90 I. of gas simultaneous with pollutant
emission test.
SLIDE 104-17
PLASTIC BAG LEAK-CHECK SYSTEM
MANOMETER
TO AIR
PRESSURE f
Q.
SLIDE 104-18
INTEGRATED SAMPLE TRAIN LEAK-CHECK
PROCEDURE
1. Attach vacuum gauge to condenser inlet.
2. Draw a vacuum of 10 in. Hg and plug line where
bag attaches.
3. Turn off pump; vacuum reading should remain
stable for 30 seconds.
D-33
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SLIDE 104-13 NOTES
ORSAT ANALYZER LEAK-CHECK PROCEDURE
1. Bring liquid level in each pipette up to reference
mark. Close pipette stopcock.
2. Bring liquid level of confining liquid onto
graduated portion of the burette. Close manifold
stopcock.
3. Record meniscus position.
4. Observe pipette and burette for 4 minutes.
The orsat analyzer passes leak-check if:
1. The liquid level in each pipette does not fall
below bottom of capillary tubing.
2. The meniscus in the burette does not change by
more than 0.2 ml.
SLIDE 104-20
DRY MOLECULAR WEIGHT DETERMINATION
1. Sample collection by any one of the three sampling
methods.
2. Sample must be analyzed within 8 hrs. after collection.
3. Analysis may be conducted using an orsat or fyrite
analyzer.
4. Repeat analysis until any three analyses differ from
their mean by no more than 0.3 Ib/lb-mole.
5. Average the three molecular weights and report results
to nearest 0.1 Ib/lb-mole.
SLIDE 104-21
DRY MOLECULAR WEIGHT EQUATION
Md = 0.44(%CO2) + 0.32(%02) + 0.28(%N2 + %CO)
where: md = dry molecular weight
%CC>2 = Percent CO-2 by volume (dry basis)
%O-2 = Percent O2 by volume (dry basis)
%CO = Percent CO by volume (dry basis)
%N2 = Percent N2 by volume (dry basis)
0.44 = molecular weight of CO2 divided by 100
0.32 = molecular weight of O2 divided by 100
0.28 = molecular weight of N2 divided by 100
D-35
-------
SLIDE 104-22
EMISSION RATE CORRECTION FACTOR
OR
EXCESS AIR DETERMINATION
1. Sampling method is specified in the standard.
2. Fyrite analyzer cannot be used.
3. Sample must be analyzed within 4 hours after
collection.
4. Pre-test and post-test leak-check of the orsat
analyzer are mandatory
5. Make repeated passes through each absorbing
solution until two consecutive readings are the
same.
NOTES
SLIDE 104-23
(cont)
6. Repeat analysis until results for any three
analyses differ by no more than:
CO2 O2 CO
1. 0.3% by volume when 1. 0.3% by volume when 1. 0.3% by volume
CO2 is > 4.0%. O2 is < 15.0%.
2. 0.2% by volume when 2.0.2% by volume when
CO2 is < 4.0%. O2 is > 15.0%.
7. Average the acceptable values and report results
to the nearest 0.1%.
SLIDE 104-24
PERCENT EXCESS AIR EQUATION
%EA =
.%O2 - 0.5%CO
0.264%N2 - (%02 - 0.5%CO)
100
where: %EA = Percent excessive air
%O2 = Percent 02 by volume (dry basis)
%CO = Percent CO by volume (dry basis)
%N2 = Percent N2 by volume (dry basis)
0.264 = Ratio of O2 to N2 in air, V/V
D-37
-------
SECTION E. METHOD 4
Subject page
1. Method 4—determination of moisture content in stack gases
(taken from Environmental Protection Agency Performance Test
Methods manual) E-3
2. Slides E-21
E-l
-------
METHOD 4—DETERMINATION OF MOISTURE CONTENT
IN STACK GASES
1. Principle and Applicability
1.1 Principle. A gas sample is extracted at a constant rate from
the source; moisture is removed from the sample stream and determined
either volumetrically or gravimetrically.
1.2 Applicability. This method is applicable for determining the
moisture content of stack gas.
Two procedures are given. The first is a reference method, for
accurate determinations of moisture content (such as are needed to
calculate emission data). The second is an approximation method, which
provides estimates of percent moisture to aid in setting isokinetic
sampling rates prior to a pollutant emission measurement run. The
approximation method described herein is only a suggested approach;
alternative means for approximating the moisture content, e.g., drying
tubes, wet bulb-dry bulb techniques, condensation techniques, stoichio-
metric calculations, previous experience, etc., are also acceptable.
The reference method is often conducted simultaneously with
a pollutant emission measurement run; when it is, calculation of percent
isokinetic, pollutant emission rate, etc., for the run shall be based upon
the results of the reference method or its equivalent; these calculations
shall not be based upon the results of the approximation method, unless
the approximation method is shown, to the satisfaction of the Administrator,
U. S. Environmental Protection Agency, to be capable of yielding results
within 1 percent H.O of the reference method.
E-3
-------
Note: The reference method may yield questionable results
when applied to saturated gas streams or to streams that contain
water droplets. Therefore, when these conditions exist or are
suspected, a second determination of the moisture content shall
be made simultaneously with the reference method, as follows: Assume
that the gas stream is saturated. Attach a temperature sensor [capable
of measuring to + 1° C (2° F)] to the reference method probe. Measure
the stack gas temperature at each traverse point (see Section 2.2.1)
during the reference method traverse; calculate the average stack gas
temperature. Next, determine the moisture percentage, either by:
(1) using a psychrometric chart and making appropriate corrections if
stack pressure is different from that of the chart, or (2) using
saturation vapor pressure tables. In cases where the psychrometric
chart or the saturation vapor pressure tables are not applicable (based
on evaluation of the process), alternate methods, subject to the approval
of the Administrator, shall be used.
2. Reference Method
The procedure described in Method 5 for determining moisture
content is acceptable as a reference method.
2.1 Apparatus. A schematic of the sampling train used in
this reference method is shown in Figure 4-1. All components
shall be maintained and calibrated according to the procedure
outlined in Method 5.
2.1.1 Probe. The probe is constructed of stainless steel or
glass tubing, sufficiently heated to prevent water condensation, and
is equipped with a filter, either in-stack (e.g., a plug of glass
E-4
-------
FILTER
(EITHER IN STACK
OR OUT OF STACK)
STACK
WALL
CONDENSER ICE BATH SYSTEM INCLUDING
SILICA GEL TUBE
PROBE
m
r
cn
MAIN VALVE
AIR TIGHT
PUMP
Figure 4-1. Moisture sampling train-reference method.
-------
wool inserted into the end of the probe) or heated out-stack (e.g.,
as described in Method 5), to remove participate matter.
When stack conditions permit, other metals or plastic tubing
may be used for the probe, subject to the approval of the
Administrator.
2.1.2 Condenser. The condenser consists of four impingers
connected in series with ground glass, leak-free fittings or any
similarly leak-free non-contaminating fittings. The first, third, and
fourth impingers shall be of the Greenburg-Smith design, modified
by replacing the tip with a 1.3 centimeter (1/2 inch) ID glass tube
extending to about 1.3 cm (1/2 in.) from the bottom of the flask.
The second impinger shall be of the Greenburg-Smith design with the
standard tip. Modifications (e.g., using flexible connections
between the impingers, using materials other than glass, or using
flexible vacuum lines to connect the filter holder to the condenser)
may be used, subject to the approval of the Administrator.
The first two impingers shall contain known volumes of water,
the third shall be empty, and the fourth shall contain a known
weight of 6- to 16-mesh indicating type silica gel, or equivalent
desiccant. If the silica gel has been previously used, dry at
175°C (350°F) for 2 hours. New silica gel may be used as received.
A thermometer, capable of measuring temperature to within 1°C
(2°F), shall be placed at the outlet of.the fourth impinger, for
monitoring purposes.
Alternatively, any system may be used (subject to the approval
of the Administrator) that cools the sample gas stream and allows
E-6
-------
measurement of both the water that has been condensed and the
moisture leaving the condenser, each to within 1 ml or 1 g.
Acceptable means are to measure the condensed water, either gravi-
metrically or volumetrically, and to measure the moisture leaving
the condenser by: (1) monitoring the temperature and pressure at
the exit of the condenser and using Dalton's law of partial pressures,
or (2) passing the sample gas stream through a tared silica gel (or
equivalent desiccant) trap, with exit gases kept below 20°C (68°F), and
determining the weight gain.
If means other than silica gel are used to determine the amount of
moisture leaving the condenser, it is recommended that silica gel (or
equivalent) still be used between the condenser system and pump, to
prevent moisture condensation in the pump and metering devices and to
avoid the need to make corrections for moisture in the metered volume.
2.1.3 Cooling System. An ice bath container and crushed ice
(or equivalent) are used to aid in condensing moisture.
2.1.4 Metering System. This system includes a vacuum gauge,
leak-free pump, thermometers capable of measuring temperature to
within 3°C (5.4°F), dry gas meter capable of measuring volume to
within 2 percent, and related equipment as shown in Figure 4-1.
Other metering systems, capable of maintaining a constant sampling
rate and determining sample gas volume, may be used, subject to the
approval of the Administrator.
2.1.5 Barometer. Mercury, aneroid, or other barometer
capable of measuring atmospheric pressure to within 2.5 mm Hg (0.1
in. Hg) may be used. In many cases, the barometric reading may be
obtained from a nearby national weather service station, in which
E-7
-------
case the station value (which is the absolute barometric pressure)
shall be requested and an adjustment for elevation differences
between the weather station and the sampling point shall be applied
at a rate of minus 2.5 mm Hg (0.1 in. Hg) per 30 m (100 ft) eleva-
tion increase or vice versa for elevation decrease.
2.1.6 Graduated Cylinder and/or Balance. The.se items are
used to measure condensed water and moisture caught in the silica
gel to within 1 ml or 0.5 g. Graduated cylinders shall have
subdivisions no greater than 2 ml. Most laboratory balances are
capable of weighing to the nearest 0.5 g or less. These balances
are suitable for use here.
2.2 Procedure. The following procedure is written for a
condenser system (such as the impinger system described in Section
2.1.2) Incorporating volumetric analysis to measure the condensed
moisture* and silica gel and gravimetric analysis to measure the
moisture leaving the condenser.
2.2.1 Unless otherwise specified by the Administrator, a minimum of
eight traverse points shall be used for circular stacks having diameters
less than 0.61 m (24 in.), a minimum of nine points shall be used for
rectangular stacks having equivalent diameters less than 0.61 m (24 in.),
and a minimum of twelve traverse points shall be used in all other cases.
The traverse points shall be located according to Method 1. The use of
fewer points is subject to the approval of the Administrator. Select a
suitable probe and probe length such that all traverse points can be
sampled. Consider sampling from opposite sides of the stack (four total
sampling ports) for large stacks, to permit use of shorter probe lengths.
Mark the probe with heat resistant tape or by some other method to
E-8
-------
denote the proper distance into the stack or duct for each sampling
point. Place known volumes of water in the first two impingers. Weigh
and record the.weight of the silica gel to the nearest 0.5 g, and
transfer the silica gel to the fourth impinger; alternatively, the
silica gel may first be transferred to the impinger, and the weight of
the silica gel plus impinger recorded.
2.2.2 Select a total sampling time such that a minimum total gas
volume of 0.60 scm (21 scf) will be collected, at a rate no greater than
•3
0.021 m /min (0.75 cfm). When both moisture content and pollutant
emission rate are to be determined, the moisture determination shall be
simultaneous with, and for the same total length of time as, the pollutant
emission rate run, unless otherwise specified in an applicable subpart of
the standards.
2.2.3 Set up the sampling train as shown in Figure 4-1. Turn on
the probe heater and (if applicable) the filter heating system to
temperatures of about 120°C (248°F), to prevent water condensation
ahead of the condenser; allow time for the temperatures to stabilize.
Place crushed ice in the ice bath container. It is recommended, but
not required, that a leak check be done, as follows: Disconnect the
probe from the first impinger or (if applicable) from the filter holder.
Plug the inlet to the first impinger (or filter holder) and pull a
380 mm (15 in.) Hg vacuum; a lower vacuum may be used, provided that
it is not exceeded during the test. A leakage rate in excess of
4 percent of the average sampling rate or 0.00057 m /min (0.02 cfm),
whichever is less, is unacceptable. Following the leak check,
reconnect the probe to the sampling train.
E-9
-------
2.2.4 During the sampling run, maintain a sampling rate
within 10 percent of constant rate, or as specified by the
Administrator. - For each run, record the data required on the
example data sheet shown in Figure 4-2. Be sure to record the
dry gas meter reading at the beginning and end of each sampling
time increment and whenever sampling is halted. Take other
appropriate readings at each sample point, at least once during
each time increment.
2.2.5 To begin sampling, position the probe tip at the first
traverse point. Immediately start the pump and adjust the flow to the
desired rate. Traverse the cross section, sampling at each traverse
point for an equal length of time. Add more ice and, if necessary, salt
to maintain a temperature of less than 20°C (68°F) at the silica gel
outlet.
2.2.6 After collecting the sample, disconnect the probe from the
filter holder (or from the first impinger) and conduct a leak check
(mandatory) as described in Section 2.2.3. Record the leak rate. If
the leakage rate exceeds the allowable rate, the tester shall either
reject the test results or shall correct the sample volume as in
Section 6.3 of Method 5. Next, measure the volume of the moisture
condensed to the nearest ml. Determine the increase in weight of the
silica gel (or silica gel plus impinger) to the nearest 0.5 g. Record
this information (see example data sheet, Figure 4-3) and calculate the
moisture percentage, as described in 2.3 below.
2.3 Calculations. Carry out the following calculations, retaining
at least one extra decimal figure beyond that of the acquired data.
Round off figures after final calculation.
E-10
-------
PLANT
LOCATION.
OPERATOR.
DATE
RUN NO..
AMBIENT TEMPERATURE.
BAROMETRIC PRESSURE.
PROBE LENGTH m«W
SCHEMATIC OF STACK CROSS SECTION
TRAVERSE POINT
NUMBER
TOTAL
SAMPLING
TIME
(8). min.
AVERAGE
STACK
TEMPERATURE
°C (°F)
PRESSURE
DIFFERENTIAL
ACROSS
ORIFICE METER
(AH).
mmlin.) HjO
METER
READING
GAS SAMPLE
VOLUME
m3(ft3)
AVm
m3 (h*)
GAS SAMPLE TEMPERATURE
AT DRY GAS METER
INLET
(Tminl. °C (°FI
Av».
Av».
OUTLET
(Tmoul), °C <°F)
Avj.
TEMPERATURE
OF GAS
LEAVING
CONDENSER OR
LAST IMPINGER,
°c <°n
Figure 4-2. Field moisture determination-reference method.
-------
FINAL
INITIAL
DIFFERENCE
IMPINGER
VOLUME.
ml
SILICA GEL
WEIGHT.
g
Figure 43. Analytical data - reference method.
E-12
-------
2.3.1 Nomenclature.
*Lc = Proportion of water vapor, by volume, in the gas stream.
Wo
Mw = Molecular weight of water, 18.0 g/g-mole (18.0 Ib/lb-mole).
Pm = Absolute pressure, (for this method, same as barometric
pressure) at the dry gas meter, mm Hg (in. Hg).
Pstd = standard absolute pressure, 760 mm Hg-(29.92 in. Hg).
R = Ideal gas constant, 0.06236 (mm Hg)(m3)/(g-mole)(°K)
for metric units and 21.85 (in. Hg)(ft3)/(lb-mole)(°R)
for English units.
Tm - Absolute temperature at meter, °K (°R).
Tstd = Standard absolute temperature, 293°K (528°R).
Vm = Dry gas volume measured by dry gas meter, dcm (dcf).
AV = Incremental dry gas volume measured by dry gas meter at
each traverse point, dcm (dcf).
V / . ,v = Dry gas volume measured by the dry gas meter, corrected
to standard conditions, dscm (dscf).
V c/stci\ = Volume of water vapor condensed corrected to standard
conditions, scm (scf).
V / .,} = Volume of water vapor collected in silica gel corrected
to standard conditions, scm (scf).
V,. = Final volume of condenser water, ml.
V. = Initial volume, if any, of condenser water, ml.
toy = Final weight of silica gel or silica gel plus impinger, g.
W- = Initial weight of silica gel or silica gel plus impinger, g.
Y = Dry gas meter calibration factor.
PW = Density of water, 0.9982 g/ml (0.002201 Ib/ml).
E-13
-------
2.3.2 Volume of water vapor condensed.
, -.
-------
2.3.5 Moisture Content.
+V
ws9(std) Equation4-4
ws Vwc(std) + Vwsg(std) + Vm(std)
Note: In saturated or moisture droplet-laden gas streams, two
calculations of the moisture content of the stack gas shall be made, one
using a value based upon the saturated conditions (see Section 1.2),
and another based upon the results of the impinger analysis. The
lower of these two values of B shall be considered correct.
WS
2.3.6 Verification of constant sampling rate. For each time
increment, determine the AV . Calculate the average. If the
m
value for any time increment differs from the average by more than
10 percent, reject the results and repeat the run.
3. Approximation Method
The approximation method described below is presented only as
a suggested method (see Section 1.2).
3.1 Apparatus.
3.1.1 Probe. Stainless steel or glass tubing, sufficiently
heated to prevent water condensation and equipped with a filter
(either in-stack or heated out-stack) to remove particulate matter.
A plug of glass wool, inserted into the end of the probe, is a
satisfactory filter.
3.1.2 Impingers. Two midget impingers, each with 30 ml
capacity, or equivalent.
3.1.3 Ice Bath. Container and ice, to aid in condensing
moisture in impingers.
E-15
-------
3.1.4 Drying Tube. Tube packed with new or regenerated 6- to 16-
mesh indicating-type silica gel (or equivalent desiccant), to dry the
sample gas and to protect the meter and pump.
3.1.5 Valve. Needle valve, to regulate the sample gas flow rate.
3.1.6 Pump. Leak-free, diaphragm type, or equivalent, to pull the
gas sample through the train.
3.1.7 Volume meter. Dry gas meter, sufficiently accurate to
measure the sample volume within 2%, and calibrated over the range of
flow rates and conditions actually encountered during sampling.
3.1.8 Rate Meter. Rotameter, to measure the flow range from
0. to 3 1pm (O.to 0.11 cfm).
3.1.9 Graduated Cylinder. 25 ml.
3.1.10 Barometer, Mercury, aneroid, or other barometer, as
described in Section 2.1.5 above.
3.1.11 Vacuum Gauge. At least 760 mm Hg (30 in. Hg) gauge, to be
usad for the sampling leak check.
3.2 Procedure.
3.2.1 Place exactly 5 ml distilled water in each impinger.
Leak check the sampling train as follows: Temporarily insert a vacuum
gauge at or near the probe inlet; then, plug the probe inlet and pull
a vacuum of at least 250 mm Hg (10 in. Hg). Note the time rate of
change of the dry gas meter dial; alternatively, a rotameter (0-40
cc/min) may be temporarily attached to the dry gas meter outlet to.
determine the leakage rate. A leak rate not in excess of 2 percent
of the average sampling rate is acceptable. Note: Carefully release
the probe inlet plug before turning off the pump.
E-16
-------
HEATED PROBE
\
SILICA GEL TUBE
\
RATE METER,
VALVE
FILTER
(GLASS WOOL)
ICE BATH
MIDGET IMPINGERS
PUMP
Figure 4-4. Moisture-sampling train - approximation method.
LOCATION
TEST
COMMENTS
DATE
OPERATOR
BAROMETRIC PRESSURE
CLOCK TIME
GAS VOLUME THROUGH
METER. (Vm),
m3 (ft3)
RATE METER SETTING
m3/min. (ft^/min.)
METER TEMPERATURE.
°C (°F)
Figure 4-5. Field moisture determination - approximation method.
E-17
-------
3.2.2 Connect the probe, insert it into the stack, and sample
at a constant rate of 2 1pm (0.071 cfm). Continue sampling until
the dry gas meter registers about 30 liters (1.1 ft ) or until
visible liquid droplets are carried over from the first impinger
to the second. Record temperature, pressure, and dry gas meter
readings as required by Figure 4-5.
3.2.3 After collecting the sample, combine the contents of
the two impingers and measure the volume to the nearest 0.5 ml.
3.3 Calculations. The calculation method presented is
designed to estimate the moisture in the stack gas; therefore,
other data, which are only necessary for accurate moisture determina-
tions, are not collected. The following equations adequately
estimate the moisture content, for the purpose of determining
isokinetic sampling rate settings.
3.3.1 Nomenclature.
B = Approximate proportion, by volume, of water vapor in
Will
the gas stream leaving the second impinger, 0.025.
BU,C = Water vapor in the gas stream, proportion by volume.
ws
M = Molecular weight of water, 18.0 g/g-mole (18.0 Ib/lb-mole)
W
P = Absolute pressure (for this method, same as barometric
pressure) at the dry gas meter.
P . . = Standard absolute pressure, 760 mm Hg (29.92 in. Hg).
R = Ideal gas constant, 0.06236 (m Hq)(m3)/(n-mole)(°K) for
metric units and 21.85 (in. Hg)(ft3)/lb-mole)(°R) for
English units.
E-18
-------
T = Absolute temperature at meter, °K (°R).
Tstd = s.tandard absolute temperature, 293°K (528°R).
V- = Final volume of impinger contents, ml.
V.j = Initial volume of impinger contents, ml.
V = Dry gas volume measured by dry gas meter, dcm (dcf).
\L(std)= Dry gas volume measured by dry gas meter, corrected
to standard conditions, dscm (dscf).
V/std\=Volume of water vapor condensed, corrected to
standard conditions, scm (scf).
Y = Dry gas meter calibration factor.
a = Density of water, 0.9982 g/ml (0.002201 Ib/ml).
w
3.3.2 Volume of water vapor collected.
tf (Vf-
V(std) -
= K1 (Vf - V^ Equation 4-5
Where:
K^ = 0.001333 m /ml for metric units.
= 0.04707 ft3/ml for English units.
3.3.3 Gas Volume.
if _ II V I '" I / 3 I" I V P
Vm(std) - Vm Y ' * M -T- ) _ „ v m •
m
Equation 4-6
E-19
-------
where:
K2 = 0.3858 K/mm Hg for metric units.
= 17.64 °R/in. Hg for English units.
3.3.4 Approximate moisture content.
Vwc(std)
Bws
Equation 4-7
4. Calibration
4.1 For the reference method, calibrate equipment as specified in
the following sections of Method 5: Section 5.3 (metering system);
Section 5.5 (temperature gauges); and Section 5.7 (barometer). The
recommended leak check of the metering system (Section 5.6 of Method 5)
also applies to the reference method. For the approximation method, use
the procedures outlined in Section 5.1.1 of Method 6 to calibrate the
metering system, and the procedure of Method 5, Section 5.7 to calibrate
the barometer.
5. Bibliography
1. Air Pollution Engineering Manual (Second Edition). Danielson,
J. A. (ed.). U. S. Environmental Protection Agency, Office of Air
Quality Planning and Standards. Research Triangle Park, N. C. Publication
No. AP-40. 1973.
2. Devorkin, Howard, et al. Air Pollution Source Testing Manual.
Air Pollution Control District, Los Angeles, Calif. November, 1963.
3. Methods for Determination of Velocity, Volume, Dust and Mist
Content of Gases. Western Precipitation Division of Joy Manufacturing
Co. Los Angeles, Calif. Bulletin WP-50. 1968.
E-20
-------
SLIDE 105-0 NOTES
METHOD — 4
Determination of Moisture
in Stack Gases
SLIDE 105-1
PRINCIPLE
A sample is extracted at a constant rate. Mois-
ture is removed and determined volumetrically
or gravimetrically.
APPLICABILITY
The method is applicable for determining
moisture content of stack gas.
SLIDE 105-2
SUMMARY OF METHODS
REFERENCE METHOD
• used for accurate determination of moisture content
• usually conducted simultaneously with a pollutant
measurement run
• results used to calculate isokinetics and pollutant
emission rate
APPROMIXATION METHOD
• used to estimate percent moisture to aid in setting iso-
kinetic sampling rate
E-21
-------
SLIDE 105-3
NOTES
(cont.) SUMMARY OF METHODS
PARTIAL PRESSURE METHOD
• used to determine moisture content in saturated gas
streams and gas streams that contain water droplets.
WET BULB - DRY BULB METHOD
• a popular alternative approximation method for low
temperature applications.
SLIDE 105-4
MOISTURE SAMPLING TRAIN (REFERENCE METHOD).
FILTER
(CITHER IN STACK
OR OUT Of STACK)
CONDENSER-ICE BATH SVSTEM
INCLUDING SILICA GEL TUBE
SLIDE 105-5
PROCEDURE
1. Determine traverse points using Method 1.
2. Select sampling time such that minimum gas volume
of 21 SCF will be collected at rate no greater than 0.75
CFM.
3. Leak-check sampling train (optional).
4. Maintain sampling rate within 10% of constant rate.
5. After sampling, leak-check sampling train (mandatory).
6. Verify the constant sampling rate.
E-23
-------
SLIDE 105-6
NOTES
MOISTURE SAMPLING TRAIN
APPROXIMATION METHOD
SLIDE 105-7
PROCEDURE
1. Place 5.0 ml of distilled water in each impinger.
2. Assemble and leak-check sampling train.
3. Sample at a constant rate of 0.07 CFM until a sample
volume of 1.1 ft' is obtained.
4. Combine contents of impingers and measure volume
to nearest 0.5 ml.
SLIDE 105-8
PARTIAL PRESSURE METHOD
1. Assume saturation.
2. Attach temperature sensor to reference method
probe.
3. Measure stack gas temperature at each traverse
point.
4. Calculate the average stack gas temperature.
5. Determine moisture fraction using saturation vapor
pressure table.
E-25
-------
SLIDE 105-9 NOTES
MOISTURE EQUATION - PARTIAL PRESSURE
S.V.R
Where: B^ = proportion (by volume) of water
vapor in a gas mixture
S.V.R - saturated vapor pressure of water
at average stack temperature
P = absolute pressure of the stack
SLIDE 105-10
EXAMPLE MOISTURE CALCULATION
DATA
Average stack temperature 140°F
Barometric pressure 29.2 in. Hg
Static pressure + 0.5 in. Hg
Saturated vapor pressure 5.88 in. Hg
CALCULATION
_ 5.88
•" 29.7
B_ = 0.1980
SLIDE 105-11
WET BULB- DRY BULB METHOD
1. Measure the wet bulb temperature.
2. Measure the dry bulb temperature.
3. Estimate moisture content using psychrometric chart.
E-27
-------
SLIDE 105-12
NOTES
MOISTURE EQUATION
(WET BULB - DRY BULB)
V.R
Where: V.R = S.V.R -
(0.000367) (P) ft,-U
S.V.R = saturated water vapor pressure at the wet
bulb temperature
P = absolute pressure in the stack
td = dry bulb temperature
t, = wet bulb temperature
V.R = water vapor pressure
E-29
-------
SECTION F. METHOD 5
Subject Page
1. Method 5--determination of participate emissions from stationary
sources (taken from Environmental Protection Agency Performance
Test Methods manual) F-l
2. Slides F-43
F-l
-------
METHOD 5—DETERMINATION OF PARTICIPATE
EMISSIONS FROM STATIONARY SOURCES
1. Principle and Applicability
1.1 Principle. Participate matter is withdrawn isokinetically
from the source and collected on a glass fiber filter maintained at
a temperature in the range of 120 +_14°C (248 +_25°F) or such other
temperature as specified by an applicable subpart of the standards
or approved by the Administrator, U. S. Environmental Protection
Agency, for a particular application. The particulate mass, which
includes any material that condenses at or above the filtration
temperature, is determined gravimetrically after removal of uncombined
water.
1.2 Applicability. This method is applicable for the determina-
tion of particulate emissions from stationary sources.
2. Apparatus
2.1 Sampling Train. A schematic of the sampling train used in
this method is shown in Figure 5-1. Complete construction details
are given in APTD-0581 (Citation 2 in Section 7); commercial models
of this train are also available. For changes from APTD-0581 and
for allowable modifications of the train shown in Figure 5-1, see
the following subsections.
The operating and maintenance procedures for the sampling train
are described in APTD-0576 (Citation 3 in Section 7). Since correct
usage is important in obtaining valid results, all users should read
APTD-0576 and adopt the operating and maintenance procedures outlined
in it, unless otherwise specified herein. The sampling train consists
of the following components:
F-3
-------
2.1.1 Probe Nozzle. Stainless steel (316) or glass with sharp,
tapered leading edge. The angle of taper shall be ^30° and the
taper shall be on the outside to preserve a constant internal diameter.
The probe nozzle shall be of the button-hook or elbow design, unless
otherwise specified by the Administrator. If made of stainless steel,
the nozzle shall be constructed from seamless tubing; other materials
of construction may be used, subject to the approval of the
Administrator.
A range of nozzle sizes suitable for isokinetic sampling should
be available, e.g., 0.32 to 1.27 cm (1/8 to 1/2 in.)--or, larger if
higher volume sampling trains are used—inside diameter (ID) nozzles
in increments of 0.16 cm (1/16 in.). Each nozzle shall be calibrated
according to the procedures outlined in Section 5.
2.1.2 Probe Liner. Borosilicate or quartz glass tubing with a
heating system capable of maintaining a gas temperature at the exit
end during sampling of 120 +_ 14°C (248 + 25°F), or such other tempera-
ture as specified by an applicable subpart of the standards or
approved by the Administrator for a particular application. (The
tester may opt to operate the equipment at a temperature lower than
that specified.) Since the actual temperature at the outlet of the
probe is not usually monitored during sampling, probes constructed
according to APTD-0581 and utilizing the calibration curves of
APTD-0576 (or calibrated according to the procedure outlined in
APTD-0576) will be considered acceptable.
F-4
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o:
i
en
TEMPERATURE SENSOR
- PROBE
TEMPERATURE
SENSOR
IMPINGER TRAIN OPTIONAL.MAY BE REPLACED
BY AN EQUIVALENT CONDENSER
HEATED AREA THERMOMETER
THERMOMETER
PITOT TUBE
PROBE
REVERSE TYPE
PITOT TUBE
PITOTMANOMETER IMPINGERS ICE BATH
BY PASS VALVE
ORIFICE
THERMOMETERS
VACUUM
GAUGE
MAIN VALVE
DRY GAS METER
AIRTIGHT
PUMP
CHECK
VALVE
VACUUM
LINE
F.ujuro 5 1. Paniculate sampling (r,im.
-------
Either borosilicate or quartz glass probe liners may be used
for stack temperatures up to about 480°C (900°F); quartz liners
shall be used, for temperatures between 480 and 900°C (900 and 1650°F).
Both types of liners may be used at higher temperatures than specified
for short periods of time, subject to the approval of the Administrator.
The softening temperature for borosilicate is 820°C (1508°F), and for
quartz it is 1500°C (2732°F).
Whenever practical, every effort should be made to use borosilicate
or quartz glass probe liners. Alternatively, metal liners (e.g., 316
stainless steel, Incoloy 825, or other corrosion resistant metals)
made of seamless tubing may be used, subject to the approval of the
Administrator.
2.1.3 Pitot Tube. Type S, as described in Section 2.1 of
Method 2, or other device approved by the Administrator. The pi tot
tube shall be attached to the probe (as shown in Figure 5-1) to allow
constant monitoring of the stack gas velocity. The impact (high
pressure) opening plane of the pi tot tube shall be even with or
above the nozzle entry plane (see Method 2, Figure 2-6b) during
sampling. The Type S pitot tube assembly shall have a known coefficient,
determined as outlined in Section 4 of Method 2.
2.1.4 Differential Pressure Gauge. Inclined manometer or
equivalent device (two), as described in Section 2.2 of Method 2.
One manometer shall be used for velocity head (Ap) readings, and
the other, for orifice differential pressure readings.
Mention of trade names or specific products does not constitute
endorsement by the Environmental Protection Agency.
F-6
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2.1.5 Filter Holder. Borosllicate glass, with a glass frit
filter support and a silicone rubber gasket. Other materials of
construction Te.g., stainless steel, Teflon, Viton) may be used,
subject to the approval of the Administrator. The holder design shall
provide a positive seal against leakage from the outside or around the
filter. The holder shall be attached immediately.at the outlet of
the probe (or cyclone, if used).
2.1.6 Filter Heating System. Any heating system capable of
maintaining a temperature around the filter holder during sampling
of 120 + 14°C (248 +_25°F), or such other temperature as specified by
an applicable subpart of the standards or approved by the
Administrator for a particular application. Alternatively, the tester
/
may opt to operate the equipment at a temperature lower than that
Specified. A temperature gauge capable of measuring temperature to
within 3°C (5.4°F) shall be installed so that the temperature around
the filter holder can be regulated and monitored during sampling.
Heating systems other than the one shown in APTD-0581 may be used.
2.1.7 Condenser. The following system shall be used to determine
the stack gas moisture content: Four impingers connected in series
with leak-free ground glass fittings or any similar leak-free non-
contaminating fittings. The first, third, and fourth impingers shall
be of the Greenburg-Smith design, modified by replacing the tip with
a 1.3 cm (1/2 in.) ID glass tube extending to about 1.3 cm (1/2 in.)
from the bottom of the flask. The second impinger shall be of the
Greenburg-Smith design with the standard tip. Modifications (e.g.,
F-7
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using flexible connections between the impingers, using materials
other than glass, or using flexible vacuum lines to connect the
filter holder* to the condenser) may be used, subject to the
approval of the Administrator. The first and second impingers shall
contain known quantities of water (Section 4.1.3), the third shall
be empty, and the fourth shall contain a known weight of silica gel,
or equivalent desiccant. A thermometer, capable of measuring tempera-
ture to within 1°C (2°F) shall be placed at the outlet of the fourth
impinger for monitoring purposes.
Alternatively, any system that cools the sample gas stream and
allows measurement of the water condensed and moisture leaving the
condenser, each to within 1 ml or 1 g may be used, subject to the
approval of the Administrator. Acceptable means are to measure the
condensed water either gravimetrically or volumetrically and to measure
the moisture leaving the condenser by: (1) monitoring the temperature
and pressure at the exit of the condenser and using Dal ton's law of
partial pressures; or (2) passing the sample gas stream through a
tared silica gel (or equivalent desiccant) trap with exit gases kept
below 20°C (68°F) and determining the weight gain.
If means other than silica gel are used to determine the amount of
moisture leaving the condenser, it is recommended that silica gel (or
equivalent) still be used between the condenser system and pump to
prevent moisture condensation in the pump and metering devices and
X
to avoid the need to make corrections for moisture in the metered
volume.
F-8
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Note: If a determination of the participate matter collected
in the impingers is desired in addition to moisture content, the
impinger system described above shall be used, without.modification.
Individual States or control agencies requiring this information
shall be contacted as to the sample recovery and analysis of the
impinger contents.
2.1.8 Metering System. Vacuum gauge, leak-free pump, thermometers
capable of measuring temperature to within 3°C (5.4°F), dry gas meter
capable of measuring volume to within 2 percent, and related equipment,
as shown in Figure 5-1. Other metering systems capable of maintaining
sampling rates within 10 percent of isokinetic and of determining
sample volumes to within 2 percent may be used, subject to the approval
of the Administrator. When the metering system is used in conjunction
with a pi tot tube, the system shall enable checks of isokinetic rates.
Sampling trains utilizing metering systems designed for higher
flow rates than that described in APTD-0581 or APTD-0576 may be used
provided that the specifications of this method are met.
2.1.9 Barometer. Mercury, aneroid, or other barometer capable
of measuring atmospheric pressure to within 2.5 mm Hg (0.1 in. Hg).
In many cases, the barometric reading may be obtained from a nearby
national weather service station, in which case the station value
(which is the absolute barometric pressure) shall be requested and
an adjustment for elevation differences between the weather station
and sampling point shall be applied at a rate of minus 2.5 mm Hg
(0.1 in. Hg) per 30 m (100 ft) elevation increase or vice versa
for elevation decrease.
F-9
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2.1.10 Gas Density Determination Equipment. Temperature
sensor and pressure gauge, as described in Sections 2.3 and 2.4 of
Method 2, and gas analyzer, if necessary, as described in Method 3.
The temperature sensor shall, preferably, be permanently attached
to the pi tot tube or sampling probe in a fixed configuration, such
that the tip of the sensor extends beyond the leading edge of the
probe sheath and does not touch any metal. Alternatively, the sensor
may be attched just prior to use in the field. Note, however, that
if the temperature sensor is attached in the field, the sensor must
be placed in an interference-free arrangement with respect to the
Type S pitot tube openings (see Method 2, Figure 2-7). As a second
alternative, if a difference of not more than 1 percent in the average
velocity measurement is to be introduced, the temperature gauge need
not be attached to the probe or pitot tube. (This alternative is
subject to the approval of the Administrator.)
2.2 Sample Recovery. The following items are needed:
2.2.1 Probe-Liner and Probe-Nozzle Brushes. Nylon bristle
brushes with stainless steel wire handles. The probe brush shall
have extensions (at least as long as the probe) of stainless steel,
Nylon, Teflon, or similarly inert material. The brushes shall be
properly sized and shaped to brush out the probe liner and nozzle.
2.2.2 Wash Bottles—Two. Glass wash bottles are recommended;
polyethylene wash bottles may be used at the option of the tester.
It is recommended that acetone not be stored in polyethylene bottles
for longer than a month.
F-10
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2.2.3 Glass Sample Storage Containers. Chemically resistant,
borosilicate glass bottles, for acetone washes, 500 ml or 1000 ml.
Screw cap liners shall either be rubber-backed Teflon or shall be
constructed so as to be leak-free and resistant to chemical attack
by acetone. (Narrow mouth glass bottles have been found to be less
prone to leakage.) Alternatively, polyethylene bottles may be used.
2.2.4 Petri Dishes. For filter samples, glass or polyethylene,
unless otherwise specified by the Administrator.
2.2.5 Graduated Cylinder and/or Balance. To measure condensed
water to within 1 ml or 1 g. Graduated cylinders shall have sub-
divisions no greater than 2 ml. Most laboratory balances are capable
of weighing to the nearest 0.5 g or less. Any of these balances is
suitable for use here and in Section 2.3.4.
2.2.6 Plastic Storage Containers. Air-tight containers to
store silica gel.
2.2.7 Funnel and Rubber Policeman. To aid in transfer of silica
gel to container; not necessary if silica gel is weighed in the field.
2.2.8 Funnel. Glass or polyethylene, to aid in sample recovery.
2.3 Analysis. For analysis, the following equipment is needed:
2.3.1 Glass Weighing Dishes.
2.3.2 Desiccator.
2.3.3 Analytical Balance. To measure to within 0.1 mg.
2.3.4 Balance. To measure to within 0.5 g.
2.3.5 Beakers. 250 ml.
2.3.6 Hygrometer. To measure the relative humidity of the
laboratory environment.
F-ll
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2.3.7 Temperature Gauge. To measure the temperature of the
laboratory environment.
3. Reagents'
3.1 Sampling. The reagents used in sampling are as follows:
3.1.1 Filters. Glass fiber filters, without organic binder,
exhibiting at least 99.95 percent efficiency (<0.05 percent penetration)
on 0.3-micron dioctyl phthalate smoke particles. The filter efficiency
test shall be conducted in accordance with ASTM standard method
D 2986-71. Test data from the supplier's quality control program are
sufficient for this purpose.
In sources containing S02 or S03, the filter material must of a type that
is unreactive to SCL or SCU. Citation 10 in Section 7 may be used to select
the appropriate filter.
3.1.2 Silica Gel. Indicating type, 6 to 16 mesh. If previously
used, dry at 175°C (350°F) for 2 hours. New silica gel may be used
as received. Alternatively, other types of desiccants (equivalent or
better) may be used, subject to the approval of the Administrator.
3.1.3 Water. When analysis of the material caught in the
impingers is required, distilled water shall be used. Run blanks
prior to field use to eliminate a high blank on test samples.
3.1.4 Crushed Ice.
3.1.5 Stopcock Grease. Acetone-insoluble, heat-stable silicone
grease. This is not necessary if screw-on connectors with Teflon
sleeves, or similar, are used. Alternatively, other types of stopcock
grease may be used, subject to the approval of the Administrator.
F-12
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3.2 Sample Recovery. Acetone—reagent grade, <0.001 percent
residue, in glass bottles—is required. Acetone from metal containers
generally has a high residue blank and should not be used. Sometimes,
suppliers transfer acetone to glass bottles from metal containers;
thus, acetone blanks shall be run prior to field use and only
acetone with low blank values (<0.001 percent) shall be used. In
no case shall a blank value of greater than 0.001 percent of the
weight of acetone used be subtracted from the sample weight.
3.3 Analysis. Two reagents are required for the analysis:
3.3.1 Acetone. Same as 3.2.
3.3.2 Desiccant. Anhydrous calcium sulfate, indicating type.
Alternatively, other types of desiccants may be used, subject to the
approval of the Administrator.
4. Procedure
4.1 Sampling. The complexity of this method is such that, in
order to obtain reliable results, testers should be trained and
experienced with the test procedures.
4.1.1 Pretest Preparation. All the components shall be maintained
and calibrated according to the procedure described in APTD-0576, unless
otherwise specified herein.
Weigh several 200 to 300 g portions of silica gel in air-tight
containers to the nearest 0.5 g. Record the total weight of the
silica gel plus container, on each container. As an alternative, the
silica gel need not be preweighed, but may be weighed directly in its
impinger or sampling holder just prior to train assembly.
Check filters visually against light for irregularities and
flaws or pinhole leaks. Label filters of the proper diameter on the
back side near the edge using numbering machine ink. As an alternative,
F-13
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label the shipping containers (glass or plastic petri dishes) and
keep the filters in these containers at all times except during
sampling and weighing.
Desiccate the filters at 20 + 5.6°C (68 + 10°F) and ambient
pressure for at least 24 hours and weigh at intervals of at least
6 hours to a constant weight, i.e., <0.5 mg change from previous
weighing; record results to the nearest 0.1 mg. During each
weighing the filter must not be exposed to the laboratory atmosphere
for a period greater than 2 minutes and a relative humidity above
50 percent. Alternatively (unless otherwise specified by the
Administrator), the filters may be oven dried at 105°C (220°F) for
2 to 3 hours, desiccated for 2 hours, and weighed. Procedures other
than those described, which account for relative humidity effects,
may be used, subject to the approval of the Administrator.
4.1.2 Preliminary Determinations. Select the sampling site and
the minimum number of sampling points according to Method 1 or as
specified by the Administrator. Determine the stack pressure,
temperature, and the range of velocity heads using Method 2; it is
recommended that a leak-check of the pitot lines (see Method 2,
Section 3.1) be performed. Determine the moisture content using
Approximation Method 4 or its alternatives for the purpose of making
isokinetic sampling rate settings. Determine the stack gas dry
molecular weight, as described in Method 2, Section 3.6; if integrated
Method 3 sampling is used for molecular weight determination, the
integrated bag sample shall be taken simultaneously with, and for
the same total length of time as, the particulate sample run.
F-14
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Select a nozzle size based on the range of velocity heads, such
that it is not necessary to change the nozzle size in order to maintain
isokinetic sampling rates. During the run, do not change the nozzle
size. Ensure that the proper differential pressure gauge is chosen for
the range of velocity heads encountered (see Section 2.2 of Method 2).
Select a suitable probe liner and probe length such that all
traverse points can be sampled. For large stacks, consider sampling
from opposite sides of the stack to reduce the length of probes.
Select a total sampling time greater than or equal to the minimum
total sampling time specified in the test procedures for the specific
industry such that (1) the sampling time per point is not less than 2
min.(or some greater time interval as specified by the Administrator),
and (2) the sample volume taken (corrected to standard conditions) will
exceed the required minimum total gas sample volume. The latter is
based on an approximate average sampling rate.
It is recommended that the number of minutes sampled at each point be
an integer or an integer plus one-half minute, in order to avoid timekeeping
errors. The sampling time at each point shall be the same.
In some circumstances, e.g., batch cycles, it may be necessary to
sample for shorter times at the traverse points and to obtain smaller
gas sample volumes. In these cases, the Administrator's approval must
first be obtained.
4.1.3 Preparation of Collection Train. During preparation and
assembly of the sampling train, keep all openings where contamination
F-15
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can occur covered until just prior to assembly or until sampling
is about to begin.
Place 100 ml of water in each of the first two impingers, leave
the third impinger empty, and transfer approximately 200 to 300 g of
preweighed silica gel from its container to the fourth impinger.
More silica gel may be used, but care should be taken to ensure that
it is not entrained and carried out from the impinger during sampling.
Place the container in a clean place for later use in the sample
recovery. Alternatively, the weight of the silica gel plus impinger
may be determined to the nearest 0.5 g and recorded.
Using a tweezer or clean disposable surgical gloves, place a
labeled (identified) and weighed filter in the filter holder. Be sure
that the filter is properly centered and the gasket properly placed
so as to prevent the sample gas stream from circumventing the filter.
Check the filter for tears after assembly is completed.
When glass liners are used, install the selected nozzle using
a Viton A 0-ring when stack temperatures are less than 260°C (500'F)
and an asbestos string gasket when temperatures are higher. See
APTD-0576 for details. Other connecting systems using either 316
stainless steel or Teflon ferrules may be used. When metal liners
are used, install the nozzle as above or by a leak-free direct
mechanical connection. Mark the probe with heat resistant tape or
by some other method to denote the proper distance into the stack or
duct for each sampling point.
F-16
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Set up the train as in Figure 5-1, using (if necessary) a very
light coat of silicone grease on all ground glass joints, greasing
only the outer-portion (see APTD-0576) to avoid possibility of
contamination by the silicone grease. Subject to the approval of
the Administrator, a glass cyclone may be used between the probe and
filter holder when the total paniculate catch is expected to exceed
100 mg or when water droplets are present in the stack gas.
Place crushed ice around the impingers.
4.1.4 Leak-Check Procedures.
4.1.4.1 Pretest Leak-Check. A pretest leak-check is recommended,
but not required. If the tester opts to conduct the pretest leak-check,
the following procedure shall be used.
After the sampling train has been assembled, turn on and set the
filter and probe heating systems at the desired operating temperatures.
Allow time for the temperatures to stabilize. If a Viton A 0-ring or
other leak-free connection is used in assembling the probe nozzle to
the probe liner, leak-check the train at the sampling site by plugging
the nozzle and pulling a 380 mm Hg (15 in. Hg) vacuum.
Note: A lower vacuum may be used, provided that it is not exceeded
during the test.
If an asbestos string is used, do not connect the probe to the
train during the leak-check. Instead, leak-check the train by first
plugging the inlet to the filter holder (cyclone, if applicable) and
pulling a 380 mm Hg (15 in. Hg) vacuum (see Note immediately above).
Then connect the probe to the train and leak-check at about 25 mm Hg
(1 in. Hg) vacuum; alternatively, the probe may be leak-checked with
F-17
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the rest of the sampling train, in one step, at 380 mm Hg (15 in. Hg)
vacuum. Leakage rates in excess of 4 percent of the average sampling
2
rate or 0.00057 m /min (0.02 cfm), whichever is less, are unacceptable.
The following leak-check instructions for the sampling train
described in APTD-0576 and APTD-0581 may be helpful. Start the pump
with bypass valve fully open and coarse adjust valve completely closed.
Partially open the coarse adjust valve and slowly close the bypass
valve until the desired vacuum is reached. Do not reverse direction
of bypass valve; this will cause water to back up into the filter
holder. If the desired vacuum is exceeded, either leak-check at
this higher vacuum or end the leak check as shown below and start over.
When the leak-check is completed, first slowly remove the plug
from the inlet to the probe, filter holder, or cyclone (if applicable)
and immediately turn off the vacuum pump. This prevents the water in
the impingers from being forced backward into the filter holder and
silica gel from being entrained backward into the third impinger.
4.1.4.2 Leak-Checks During Sample Run. If, during the sampling
run, a component (e.g., filter assembly or impinger) change becomes
necessary, a leak-check shall be conducted immediately before the
change is made. The leak-check shall be done according to the procedure
outlined in Section 4.1.4.1 above, except that it shall be done at a
vacuum equal to or greater than the maximum value recorded up to that
point in the test. If the leakage rate is found to be no greater than
0.00057 m /min (0.02 cfm) or 4 percent of the average sampling rate
F-18
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(whichever is less), the results are acceptable, and no correction
will need to be applied to the total volume of dry gas metered;
if, however, a higher leakage rate is obtained, the tester shall
either record the leakage rate and plan to correct the sample volume
as shown in Section 6.3 of this method, or shall void the sampling run.
Immediately after component changes, leak-checks are optional;
if such leak-checks are done, the procedure outlined in Section 4.1.4.1
above shall be used.
4.1.4.3 Post-test Leak-Check. A leak-check is mandatory at the
conclusion of each sampling run. The leak-check shall be done in
accordance with the procedures outlined in Section 4.1.4.1, except
that it shall be conducted at a vacuum equal to or greater than the
maximum value reached during the sampling run. If the leakage rate
is found to be no greater than 0.00057 m /min (0.02 cfm) or 4 percent
of the average sampling rate (whichever is less), the results are
acceptable, and no correction need be applied to the total volume of
dry gas metered. If, however, a higher leakage rate is obtained, the
tester shall either record the leakage rate and correct the sample
volume as shown in Section 6.3 of this method, or shall void the
sampling run.
4.1.5 Particulate Train Operation. During the sampling run,
maintain an isokinetic sampling rate (within 10 percent of true
isokinetic unless otherwise specified by the Administrator) and a
temperature around the filter of 120 +. 14eC (248 £ 25°F), or such other
F-19
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temperature as specified by an applicable subpart of the standards
or approved by the Administrator.
For each run, record the data required on a data sheet such as
the one shown in Figure 5-2. Be sure to record the initial dry gas
meter reading. Record the dry gas meter readings at the beginning
and end of each sampling time increment, when changes in flow rates
are made, before and after each leak check, and when sampling is halted.
Take other readings required by Figure 5-2 at least once at each sample
point during each time increment and additional readings when significant
changes (20 percent variation in velocity head readings) necessitate
additional adjustments in flow rate. Level and zero the manometer.
Because the manometer level and zero may drift due to vibrations and
temperature changes, make periodic checks during the traverse.
Clean the portholes prior to the test run to minimize the chance
of sampling deposited material. To begin sampling, remove the nozzle
cap, verify that the filter and probe heating systems are up to
temperature, and that the pi tot tube and probe are properly positioned.
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. Nomographs are available, which
aid in the rapid adjustment of the isokinetic sampling rate without
excessive computations. These nomographs are designed for use when the
Type S pitot tube coefficient is 0.85 +0.02, and the stack gas
equivalent density (dry molecular weight) is equal to 29 +_4. APTD-0576
details the procedure for using the nomographs. If C and M. are
outside the above stated ranges, do not use the nomographs unless
appropriate steps (see Citation 7 in Section 7) are taken to compensate
for the deviations.
F-20
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PLANT
LOCATION.
OPERATOR.
DATE
RUN NO.
SAMPLE BOX NO..
METER BOX NO._
METERAH@
CFACTOR
AMBIENT TEMPERATURE
BAROMETRIC PRESSURE.
ASSUMED MOISTURE. %_
PROBE LENGTH, m
°C (°F)
VELOCITY
HEAD
|APS),
mmlin.JH^O
PRESSURE
DIFFERENTIAL
ACROSS
ORIFICE
METER
mm HjO
-------
When the stack is under significant negative pressure (height
of impinger stem), take care to close the coarse adjust valve before
inserting the probe into the stack to prevent water from backing into
the filter holder. If necessary, the pump may be turned on with the
coarse adjust valve closed. .
When the probe is in position, block off the openings around
the probe and porthole to prevent unrepresentative dilution of the
gas stream.
Traverse the stack cross-section, as required by Method 1 or as
specified by the Administrator, being careful not to bump the probe
nozzle into the stack walls when sampling near the walls or when
removing or inserting the probe through the portholes; this minimizes
the chance of extracting deposited material.
During the test run, make periodic adjustments to keep the
temperature around the filter holder at the proper level; add more
ice and, if necessary, salt to maintain a temperature of less than
20°C (68°F) at the condenser/silica gel outlet. Also, periodically
check the level and zero of the manometer.
If the pressure drop across the filter becomes too high, making
isokinetic sampling difficult to maintain, the filter may be replaced
in the midst of a sample run. It is recommended that another complete
filter assembly be used rather than attempting to change the filter
itself. Before a new filter assembly is installed, conduct a leak-check
(see Section 4.1.4.2). The total particulate weight shall include the
summation of all filter assembly catches.
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A single train shall be used for the entire sample run, except
in cases where simultaneous sampling is required in two or more
separate ducts or at two or more different locations within the same
duct, or, in cases where equipment failure necessitates a change of
trains. In all other situations, the use of two or more trains will
be subject to the approval of the Administrator. .
Note that when two or more trains are used, separate analyses of
the front-half and (if applicable) impinger catches from each train
shall be performed, unless identical nozzle sizes were used on all
trains, in which case, the front-half catches from the individual trains
may be combined (as may the impinger catches) and one analysis of front-
half catch and one analysis of impinger catch may be performed. Consult
with the Administrator for details concerning the calculation of
results when two or more trains are used.
At the end of the sample run, turn off the coarse adjust valve,
remove the probe and nozzle from the stack, turn off the pump, record
the final dry gas meter reading, and conduct a post-test leak-check, as
outlined in Section 4.1.4.3. Also, leak-check the pitot lines as
described in Method 2, Section 3.1; the lines must pass this leak-check,
in order to validate the velocity head data.
4.1.6 Calculation of Percent Isokinetic. Calculate percent
isokinetic (see Calculations, Section 6) to determine whether the run
was valid or another test run should be made. If there was difficulty
in maintaining isokinetic rates due to source conditions, consult with
the Administrator for possible variance on the isokinetic rates.
F-23
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4.2 Sample Recovery. Proper cleanup procedure begins as soon
as the probe .is removed from the stack at the end of the sampling
period. Allow the probe to cool.
When the probe can be safely handled, wipe off all external
particulate matter near the tip of the probe nozzle and place a cap
over it to prevent losing or gaining particulate matter. Do not cap
off the probe tip tightly while the sampling train is cooling down
as this would create a vacuum in the filter holder, thus drawing water
from the impingers into the filter holder.
Before moving the sample train to the cleanup site, remove the
probe from the sample train, wipe off the silicone grease, and cap
the open outlet of the probe. Be careful not to lose any condensate
that might be present. Wipe off the silicone grease from the filter
inlet where the probe was fastened and cap it. Remove the umbilical
cord from the last impinger and cap the impinger. If a flexible line
is used between the first impinger or condenser and the filter holder,
disconnect the line at the filter holder and let any condensed water
or liquid drain into the impingers or condenser. After wiping off the
silicone grease, cap off the filter holder outlet and impinger inlet.
Either ground-glass stoppers, plastic caps, or serum caps may be used
to close these openings.
Transfer the probe and filter-impinger assembly to the cleanup
area. This area should be clean and protected from the wind so that
the chances of contaminating or losing the sample will be minimized.
F-24
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Save a portion of the acetone used for cleanup as a blank. Take
200 ml of this acetone directly from the wash bottle being used and
place it in a glass sample container labeled "acetone blank."
Inspect the train prior to and during disassembly and note any
abnormal conditions. Treat the samples as follows:
Container No. 1. Carefully remove the filter from'the filter holder
and place it in its identified petri dish container. Use a pair of
i
tweezers and/or clean disposable surgical gloves to handle the filter.
If it is necessary to fold the filter, do so such that the particulate
cake is inside the fold. Carefully transfer to the petri dish any
particulate matter and/or filter fibers which adhere to the filter
holder gasket, by using a dry Nylon bristle brush and/or a sharp-edged
blade. Seal the container.
Container No. 2. Taking care to see that dust on the outside
of the probe or other exterior surfaces does not get into the sample,
quantitatively recover particulate matter or any condensate from the
probe nozzle, probe fitting, probe liner, and front half of the
filter holder by washing these components with acetone and placing
the wash in a glass container. Distilled water may be used instead
of acetone when approved by the Administrator and shall be used when
specified by the Administrator; in these cases, save a water blank
and follow the Administrator's directions on analysis. Perform the
acetone rinses as follows:
F-25
-------
Carefully remove the probe nozzle and clean the inside surface
by rinsing with acetone from a wash bottle and brushing with a Nylon
bristle brush. Brush until the acetone rinse shows no visible particles,
after which make a final rinse of the inside surface with acetone. .
Brush and rinse the inside parts of the Swagelok fitting with
acetone in a similar way until no visible particles remain.
Rinse the probe liner with acetone by tilting and rotating the
probe while squirting acetone into its upper end so that all inside
surfaces will be wetted with acetone. Let the acetone drain from the
lower end into the sample container. A funnel (glass or polyethylene)
may be used to aid in transferring liquid washes to the container. Follow
the acetone rinse with a probe brush. Hold the probe in an inclined
position, squirt acetone into the upper end as the probe brush is being
pushed with a twisting action through the probe; hold a sample container
underneath the lower end of the probe, and catch any acetone and particu-
late matter which is brushed from the probe. Run the brush through the
probe three times or more until no visible particulate matter is carried
out with the acetone or until none remains in the probe liner on visual
inspection. With stainless steel or other metal probes, run the brush
through in the above prescribed manner at least six times since metal
probes have small crevices in which particulate matter can be entrapped.
Rinse the brush with acetone, and quantitatively collect these washings
in the sample container. After the brushing, make a final acetone rinse
of the probe as described above.
F-26
-------
It Is recommended that two people be used to clean the probe
to minimize sample losses. Between sampling runs, keep brushes clean
and protected from contamination.
After ensuring that all joints have been wiped clean of silicone
grease, clean the inside of the front half of the filter holder by
rubbing the surfaces with a Nylon bristle brush and rinsing with
acetone. Rinse each surface three times or more if needed to remove
visible particulate. Make a final rinse of the brush and filter
holder. Carefully rinse out the glass cyclone, also (if applicable).
After all acetone washings and particulate matter have been collected
in the sample container, tighten the lid on the sample container so
that acetone will not leak out when it is shipped to the laboratory.
Mark the height of the fluid level to determine whether or not
leakage occurred during transport. Label the container to clearly
identify its contents.
Container No. 3. Note the color of the indicating silica gel
to determine if it has been completely spent and make a notation of
its condition. Transfer the silica gel"from the fourth impinger to
its original container and seal. A funnel may make it easier to pour
the silica gel without spilling. A rubber policeman may be used as
an aid in removing the silica gel from the impinger. It is not
necessary to remove the small amount of dust particles that may adhere
to the impinger wall and are difficult to remove. Since the gain in
weight is to be used for moisture calculations, do not use any water
F-27
-------
or other liquids to transfer the silica gel. If a balance is
available in the field, follow the procedure for container No. 3
in Section 4.3.
Impinger Water. Treat the impingers as follows: Make a
notation of any color or film in the liquid catch. Measure the
liquid which is in the first three impingers to within +1 ml by
using a graduated cylinder or by weighing it to within +0.5 g by
using a balance (if one is available). Record the volume or weight
of liquid present. This information is required to calculate the
moisture content of the effluent gas. .
Discard the liquid after measuring and recording the volume or
weight, unless analysis of the Impinger catch is required (see Note,
Section 2.1.7).
If a different type of condenser is used, measure the amount of
moisture condensed either volumetrically or gravimetrically.
Whenever possible, containers should be shipped in such a way that
they remain upright at all times.
4.3 Analysis. Record the data required on a sheet such as the
one shown in Figure 5-3. Handle each sample container as follows:
Container No. 1. Leave the contents in the shipping container
or transfer the filter and any loose particulate from the sample
container to a tared glass weighing dish. Desiccate for 24 hours
in a desiccator containing anhydrous calcium sulfate. Weigh to a
constant weight and report the results to the nearest 0.1 mg. For
purposes of this Section, 4.3, the term "constant weight" means
F-28
-------
Plant.
Date
Run No
Filter No
Amount liquid lost during transport
Acetone blank volume, ml
Acetone wash volume, ml
Acetone blank concentration, mg/mg (equation 5-4).
Acetone wash blank, mg (equation 5-5)
CONTAINER
NUMBER
1
2
TOTAL
WEIGHT OF PARTICIPATE COLLECTED.
mg
FINAL WEIGHT
^^xCl
TARE WEIGHT
2^x^
Less acetone blank
Weight of paniculate matter
WEIGHT GAIN
FINAL
INITIAL
LIQUID COLLECTED
TOTAL VOLUME COLLECTED
VOLUME OF LIQUID
WATER COLLECTED
IMPINGER
VOLUME,
ml
SILICA GEL
WEIGHT,
9
g* ml
•CONVERT WEIGHT OF WATER TO VOLUME BY DIVIDING TOTAL WEIGHT
INCREASE BY DENSITY OF WATER (1g/ml).
INCREASE" 9 = VOLUME WATER, ml
1 g/ml
Figure 5-3. Analytical data.
F-29
-------
a difference of no more than 0.5 mg or 1 percent of total weight
less tare weight, whichever is greater, between two consecutive
weighings, with no less than 6 hours of desiccation time between
weighings.
Alternatively, the sample may be oven dried at 105°C (220°F) for
2 to 3 hours, cooled in the desiccator, and weighed to a constant
weight, unless otherwise specified by the Administrator. The tester
may also opt to oven dry the sample at 105°C (220°F) for 2 to 3 hours,
weigh the sample, and use this weight as a final weight.
Container No. 2. Note the level of liquid in the container and
confirm on the analysis sheet whether or not leakage occurred during
transport. If a noticeable amount of leakage has occurred, either void
the sample or use methods, subject to the approval of the Administrator,
to correct the final results. Measure the liquid in this container
either volumetrically to +1 ml or gravimetrically to +0.5 g. Transfer
the contents to a tared 250-ml beaker and evaporate to dryness at ambient
temperature and pressure. Desiccate for 24 hours and weigh to a
constant weight. Report the results to the nearest 0.1 mg.
Container No. 3. Weigh the spent silica gel (or silica gel plus
impinger) to the nearest 0.5 g using a balance. This step may be con-
ducted in the field.
"Acetone Blank" Container. Measure acetone in this container
either volumetrically or gravimetrically. Transfer the acetone to
a tared 250-ml beaker and evaporate to dryness at ambient temperature
and pressure. Desiccate for 24 hours and weigh to a constant weight.
Report the results to the nearest 0.1 mg.
F-30
-------
Note: At the option of the tester, the contents of Container
No. 2 as well as the acetone blank container may be evaporated at
temperatures higher than ambient. If evaporation is done at an
elevated temperature, the temperature must be below the boiling point
of the solvent; also, to prevent "bumping," the evaporation process
must be closely supervised, and the contents of the beaker must be
swirled occasionally to maintain an even temperature. Use extreme
care, as acetone is highly flammable and has a low flash point.
5. Calibration
Maintain a laboratory log of all calibrations.
5.1 Probe Nozzle. Probe nozzles shall be calibrated before
their initial use in the field. Using a micrometer, measure the
inside diameter of the nozzle to the nearest 0.025 mm (0.001 in.).
Make three separate measurements using different diameters each time,
and obtain the average of the measurements. The difference between
the high and low numbers shall not exceed 0.1 mm (0.004 in.). When
nozzles become nicked, dented, or corroded, they shall be reshaped,
sharpened, and recalibrated before use. Each nozzle shall be per-
manently and uniquely identified.
5.2 Pi tot Tube. The Type S pi tot tube assembly shall .be calibrated
according to the procedure outlined in Section 4 of Method 2.
5.3 Metering System. Before its initial use in the field, the
metering system shall be calibrated according to the procedure outlined
in APTD-0576. Instead of physically adjusting the dry gas meter dial
readings to correspond to the wet test meter readings, calibration
factors may be used to mathematically correct the gas meter dial readings
to the proper values. Before calibrating the metering system, it is sug-
gested that a leak-check be conducted. For metering systems having diaphragm
F-31
-------
pumps, the normal leak-check procedure will not detect leakages within
the .pump. For these cases the following leak-check procedure is
suggested:make a 10-minute calibration run at 0.00057 m3/min (0.02 cfm);
at the end of the run, take the difference of the measured wet test meter
and dry gas meter volumes; divide the difference by 10, to get the leak
rate. The leak rate should not exceed 0.00057 m3/min (0.02 cfm).
After each field use, the calibration of the metering system
shall be checked by performing three calibration runs at a single,
intermediate orifice setting (based on the previous field test), with
the vacuum set at the maximum value reached during the test series.
To adjust the vacuum, insert a valve between the wet test meter and
the inlet of the metering system. Calculate the average value of the
calibration factor. If the calibration has changed by more than 5 per-
cent, recalibrate the meter over the full range of'orifice settings, as
outlined in APTD-0576.
Alternative procedures, e.g., using the orifice meter coeffi-
cients, may be used, subject to the approval of the Administrator.
Note: If the dry gas meter coefficient values obtained before
and after a test series differ by more than 5 percent, the test
series.shall either be voided, or calculations for the test series
shall be performed using whichever meter coefficient value (i.e.,
before or after) gives the lower value of total sample volume.
5.4 Probe Heater Calibration. The probe heating system shall be
calibrated before its initial use in the field according to the pro-
cedure outlined in APTD-0576. Probes constructed according to APTD-0581
need not be calibrated if the calibration curves in APTD-0576 are used.
5.5 Temperature Gauges. Use the procedure in Section 4.3 of
Method 2 to calibrate in-stack temperature gauges. Dial thermometers,
F-32
-------
such as are used for the dry gas meter and condenser outlet, shall be
calibrated against mercury-in-glass thermometers.
5.6 Leak Check of Metering System Shown in Figure 5-1. That
portion of the sampling train from the pump to the orifice meter
should be leak checked prior to initial use and after each shipment.
Leakage after the pump will result in less volume being recorded than
is actually sampled. The following procedure is suggested (see
Figure 5-4): Close the main valve on the meter box. Insert a one-
hole rubber stopper with rubber tubing attached into the orifice
exhaust pipe. . Disconnect and vent the low side of the orifice manometer.
Close off the low side orifice tap. Pressurize the system to 13 to
18 cm (5 to 7 in.) water column by blowing into the rubber tubing.
Pinch off the tubing and observe the manometer for one minute. A loss
of pressure on the manometer indicates a leak in the meter box; leaks,
if present, must be corrected.
5.7 Barometer. Calibrate against a mercury barometer.
6. Calculations
Carry out calculations, retaining at least one extra decimal
figure beyond that of the acquired data. Round off figures after
the final calculation. Other forms of the equations may be used as
long as they give equivalent results.
6.1 Nomenclature.
2 2
A = Cross-sectional area of nozzle, m (ft ).
B = Water vapor in the gas stream, proportion by volume.
W5>
C = Acetone blank residue concentration, mg/g.
a
c = Concentration of particulate matter in stack gas, dry
basis, corrected to standard conditions, g/dscm (g/dscf).
I = Percent of isokinetic sampling.
F-33
-------
CO
-p.
RUBBER
TUBING
RUBBER
STOPPER
ORIFICE
VACUUM
GAUGE
BLOW INTO TUBING
UNTIL MANOMETER
READS 5 TO 7 INCHES
WATER COLUMN
ORIFICE
MANOMETER
MAIN VALVE
CLOSED
AIRTIGHT
PUMP
Figure 54. Leak check of meter box.
-------
L. = Maximum acceptable leakage rate for either a pretest
a
- leak check or for a leak check following a component
change; equal to 0.00057 m /min (0.02 cfm) or 4 percent
of the average sampling rate, whichever is less.
L. = Individual leakage rate observed during the leak check
conducted prior to the "i " component change (i = 1,
2, 3 ---- n), m /min (cfm).
L = Leakage rate observed during the post-test leak check,
o
m /min (cfm).
m = Total amount of parti cul ate matter collected, mg.
n
M = Molecular weight of water, 18.0 g/g-mole (18.0 Ib/lb-mole).
W
m_ = Mass of residue of acetone after evaporation, mg.
a
P. = Barometric pressure at the sampling site, mm Hg (in. Hg).
Dar
P = Absolute stack gas pressure, mm Hg (in. Hg).
P . = Standard absolute pressure, 760 mm Hg (29.92 in. Hg).
R = Ideal gas constant, 0.06236 mm Hg-m /°K-g-mole (21.85 in.
Hg-ft3/°R-lb-mole).
T = Absolute average dry gas meter temperature (see Figure 5-2),
°
K
T = Absolute average stack gas temperature (see Figure 5-2),
°
K
T .d = Standard absolute temperature, 293°K (528°R).
V = Volume of acetone blank, ml.
a
Va = Volume of acetone used in wash, ml.
uW
F-35
-------
V, = Total volume of liquid collected in impingers and
silica gel (see Figure 5-3), ml.
V = Volume of gas sample as measured by dry gas meter,
dcm (dcf).
V / . .1= Volume of gas sample measured by the dry gas meter,
corrected to standard conditions, dscm (dscf).
V/std)= Volume of water vapor in the gas sample, corrected to
standard conditions, scm (scf).
v - Stack gas velocity, calculated by Method 2, Equation 2-9,
using data obtained from Method 5, m/sec (ft/sec).
W = Weight of residue in acetone wash, mg.
a
Y - Dry gas meter calibration factor.
AH = Average pressure differential across the orifice meter
(see Figure 5-2), mm H20 (in. H20).
p = Density of acetone, rig/ml (see label on bottle).
a
p = Density of water, 0.9982 g/ml (0.002201 Ib/ml).
W
6 = Total sampling time, min.
e, = Sampling time interval, from the beginning of a run until
the first component change, min.
8. = Sampling time interval, between two successive component
changes, beginning with the interval between the first
and second changes, min.
6 = Sampling time interval, from the final (n ) component
change until the.end of the sampling run, min.
F-36
-------
13.6 = Specific gravity of mercury.
60 = Sec/min.
100 = Conversion to percent.
6.2 Average dry gas meter temperature and average orifice
pressure drop. See data sheet (Figure 5-2).
6.3 Dry Gas Volume. Correct the sample volume measured by the
dry gas meter to standard conditions (20°C, 760 mm Hg or 68°F,
29.92 in. Hg) by using Equation 5-1.
{
T
std)
V
Ph,_ + 4H
bar T3T
Pstd
. KVY ptar *(»H/13.6)
1 " Tm
Vstd) = V
y 111 / o i»u
Equation 5-1
where:
KI = 0.3858 pK/mm Hg for metric units
= 17.64 °R/1n. Hg for English units
Note: Equation 5-1 can be used as written unless the leakage
rate observed during any of the mandatory leak checks (i.e., the
post-test leak check or leak checks conducted prior to component
changes) exceeds L . If !_„ or I_. exceeds L , Equation 5-1 must be
a p I a
modified as follows:
(a) Case I. No component changes made during sampling run. In
this case, replace V in Equation 5-1 with the expression:
V* - ']
F-37
-------
(b) Case II. One or more component changes made during the
sampling run. In this case, replace V in Equation 5-1 by the
expression:
- La> 91 - 91 - 'S - La>
and substitute only for those leakage rates (l_. or L ) which exceed
6.4 Volume of water vapor.
V ,c^ = Vlr( SHI K-^-J = K, Ylf. Equation 5-2
'w(std) * ¥lc,..w
where:
K2 = 0.001333 m /ml for metric units
= 0.04707 ft3/ml for English units
6.5 Moisture Content.
Bws = V , V Equation 5-3
ws Vm(std) w(std)
Mote: In saturated or water droplet-laden gas streams, two
calculations of the moisture content of the stack gas shall be made,
one from the impinger analysis (Equation 5-3), and a second from the
assumption of saturated conditions. The lower of the two values of
B,,_ shall be considered correct. The procedure for determining the
ws
moisture content based upon assumption of saturated conditions is
given in the Note of Section 1.2 of Method 4. For the purposes of this
method, the average stack gas temperature from Figure 5-2 may be used to
make this determination, provided that the accuracy of the in-stack
temperature sensor is +_ 1°C (2°F).
F-38
-------
6.6 Acetone Blank Concentration.
ma
C = V p_ Equation 5-4
a a a
6.7 Acetone Wash Blank.
Wa = Ca Vaw pa Equation 5-5
6.8 Total Particulate Weight. Determine the total particulate
catch from the sum of the weights obtained from containers 1 and 2
less the acetone blank (see Figure 5-3). Note: Refer to Section
4.1.5 to assist in calculation of results involving two or more
filter assemblies or two or more sampling trains.
6.9 Particulate Concentration.
c$ = (0.001 g/mg) (mn/Vm(stdp Equation 5-6
6.10 Conversion Factors:
From To Multiply by
scf m3 0.02832
g/ft3 gr/ft3 15.43
g/ft3 lb/ft3 2.205 x 10"3
g/ft3 g/m3 35.31
6.11 Isokinetic Variation.
6.11.1 Calculation From Raw Data.
, . 100 Ts [K3 V1c * (V, Y/TJ (Pbar * AH/13.6)]
60 9 v P A
Equation 5-7
F-39
-------
where:
K- = 0.00.3454 mm Hg-m3/ml-°K for metric units
= 0.002669 in. Hg-ft3/ml-°R for English units.
6.11.2 Calculation From Intermediate Values.
, . Ts Vstd) Pstd
"
Tstd vs 8 An ps 60 "-««'
" "4 Ps \ ^'^'^ws'
where :
K4 = 4.320 for metric units
= 0.09450 for English units.
6.12 Acceptable Results. If 90 percent l I l 110 percent, the
results are acceptable. If the results are low in comparison to the
standard and I is beyond the acceptable range, or, if I is less than
90 percent, the Administrator may opt to accept the results. Use
Citation 4 to make judgments. Otherwise, reject the results and repeat
the test.
7. Bibliography
1. Addendum to Specifications for Incinerator Testing at Federal
Facilities. PHS, NCAPC. Dec. 6, 1967.
2. Martin, Robert M. Construction Details of Isokinetic Source-
Sampling Equipment. Environmental Protection Agency. Research
Triangle Park, N. C. APTD-0581. April, 1971.
3. Rom, Jerome J. Maintenance, Calibration, and Operation
of Isokinetic Source Sampling Equipment. Environmental Protection
Agency. Research Triangle Park, N. C. APTD-0576. March, 1972.
F-40
-------
4. Smith, W. S., R. T. Shigehara, and W. F. Todd. A Method
of Interpreting Stack Sampling Data. Paper Presented at the
63d Annual Meeting of the Air Pollution Control Association,
St. Louis, Mo. June 14-19, 1970.
5. Smith, W. S., et al. Stack Gas Sampling Improved and
Simplified With New Equipment. APCA Paper No. 67-119. 1967.
6. Specifications for Incinerator Testing at Federal Facilities.
PHS, NCAPC. 1967.
7. Shigehara, R.T. Adjustments in the EPA Nomograph for
Different Pitot Tube Coefficients and Dry Molecular Weights. Stack
Sampling News ^:4-ll. October, 1974.
8. Vollaro, R. F. A Survey of Commercially Available Instrumentation
For the Measurement of Low-Range Gas Velocities. U. S. Environmental
Protection Agency, Emission Measurement Branch. Research Triangle
Park, N. C. November, 1976 (unpublished paper).
9. Annual Book of ASTM Standards. Part 26. Gaseous Fuels;
Coal and Coke; Atmospheric Analysis. American Society for Testing
and Materials. Philadelphia, Pa. 1974. pp. 617-622.
10. Felix, L. G., G. I. Clinard, G. E. Lacey, and J. D. McCain.
Inertial Cascade Impactor Substrate Media for Flue Gas Sampling.
U. S. Environmental Protection Agency. Research Triangle Park, N. C.
27711, Publication No. EPA-600/7-77-060. June 1977, 83 p.
F-41
-------
SLIDE 106-0 NOTES
METHOD — 5
Determination of Particulate Emissions
From Stationary Sources
SLIDE 106-1
PRINCIPLE
Particulate matter is withdrawn isokinetically from
the source and collected on a glass fiber filter main-
tained at a temperature in the range of 248 ± 25°F.
The particulate mass is determined gravimetri-
cally after removal of uncombined water.
APPLICABILITY
This method is applicable for the determination
of particulate emissions from stationary sources.
F-43
-------
SLIDE 106-2
NOTES
P;EPA :-
METHOD i
j Partieulat*t
SLIDE 106-3
•.••.•••.•.••.••.•••yy---'---:y.::::v.
F-45
-------
SLIDE 106-4
NOTES
SLIDE 106-5
F-47
-------
SLIDE 106-6
NOTES
SLIDE 106-7
F-49
-------
SLIDE 106-8
NOTES
COMPONENT CALIBRATION
PROBE NOZZLE
1. Measure three diameters of the nozzle.
2. Calculate the average measurement.
3. The difference between the high and low measure-
ment shall not exceed 0.004 in.
4. Nozzle should be uniquely identified.
SLIDE 106-9
F-51
-------
SLIDE 106-10
NOTES
METERING SYSTEM
SLIDE 106-11
SAMPLE METER SYSTEM CALIBRATION SETUP
MANOMETER
LEVEL ADJUST
F-53
-------
SLIDE 106-12
NOTES
SLIDE 106- 13
TEMPERATURE GAUGE CALIBRATION
IMPINGER THERMOMETER
Calibrate with a mercury-in-glass thermometer which
meets ASTM E-1 No. 63C or 63F specifications.
1. compare readings in ice bath
2. compare readings at room temperature
3. thermometer must agree within 2°F of the reference
thermometer at both temperatures
DRY GAS METER THERMOMETER
Calibrate with a mercury-in-glass thermometer which
meets ASTM specifications.
1. compare readings in hot water bath 105° - 122°F
2. compare readings at room temperature
3. thermometers must agree within 5.4°F at both points or
differential at both points within 5.4°F
F-55
-------
SLIDE 106-14
NOTES
SLIDE 106-15
PROBE HEATER CALIBRATION
Calibrate probe heater if not constructed according to
APTD - 0581 using procedure outlined in APTD - 0576
BALANCE CALIBRATION
ANALYTICAL BALANCE
• Calibrate using Class-S weights.
(balance should agree within ± 2 mg)
TRIP BALANCE
• Calibrate using Class-S weights
(balance should agree within ± 0.5 g)
F-57
-------
SLIDE 106-16
NOTES
PROJECTED AREA MODELS FOR TYPICAL
PITOBE ASSEMBLIES
PERCENT
THEORETICAL =
BLOCKAGE
I x w
DUCT AREA
X100
SLIDE 106-17
ADJUSTMENT OF TYPE "S" PITOT TUBE
COEFFICIENTS TO ACCOUNT FOR BLOCKAGE
w
o
O
u
LU
m
£L
z
S
e
u
S
1 in. CYLINDRICAL MODEL;
USE FOR ASSEMBLIES WITH
NO EXTERNAL SHEATH.
2Vi in. CYLINDRICAL MODEL;
USE FOR ASSEMBLIES WITH _
EXTERNAL SHEATH.
234
THEORETICAL BLOCKAGE, %
F-59
-------
SLIDE 106-18
NOTES
4 &£"?:.•*•* i--"V •*" .^
-------
SLIDE 3.06-20
NOTES
SAMPLE RECOVERY
FILTER
1. Carefully remove filter from filter holder and place it in
designated petri dish.
2. Seal and label petri dish.
PROBE AND CONNECTING GLASSWARE
1. Clean outside of probe, pitot tube and nozzle.
2. Remove nozzle and rinse and brush inside surface until
rinse is clear.
3. Rinse and brush probe.
A. a minimum of 3 rinses for glass lined probes
B. a minimum of 6 rinses for metal lined probes
4. Brush and rinse front half of filter holder.
5. Clean connecting glassware which precedes filter
holder.
SLIDE 106-21
F-63
-------
SLIDE 106-22
NOTES
SLIDE 106-23
PROBE AND CONNECTING GLASSWARE (cont.)
6. Securely seal sample bottle and mark liquid level.
7. Collect acetone blank sample.
CONDENSER
1. Determine liquid quantity in impingers to nearest 1 ml
or 0.5 g.
2. Make note of any color or film in impinger water.
SILICA GEL
1. Note color of silica gel to determine if spent.
2. Determine weight gain to nearest 0.5 g.
F-65
-------
SLIDE 106-24 NOTES
ANALYSIS
FILTER
1. Desiccate filter for a minimum of 24 hrs.
2. Weigh to a constant weight and record results to near-
est 0.1 mg.
3. Alternatively, filter may be oven dried at 220°F for 2 to 3
hrs., cooled in desiccator, and weighed to constant
weight.
4. Analyze blank filter in same manner as sample filter.
SLIDE 106-25
(cont.) ANALYSIS
ACETONE RINSE
1. Confirm that no leakage occurred during shipment.
2. Measure contents of container to nearest 1 ml or 0.5 g.
3. Transfer to tared beaker; evaporate and desiccate for
24 hrs.
4. Weigh to constant weight; report data to nearest 0.1 mg.
5. Alternatively, acetone rinse may be evaporated at ele-
vated temperature (below 133°F).
6. Analyze blank in same manner as the sample.
F-67
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SECTION G. METHOD 6
Subject
1. Method 6—determination of sulfur dioxide emissions from
stationary sources (taken from Environmental Protection Agency
Performance Test Methods manual) G-3
2. Slides G-19
6-1
-------
METHOD 6—DETERMINATION OF SULFUR DIOXIDE
EMISSIONS FROM STATIONARY SOURCES
1. Principle and Applicability
1.1. Principle. A gas sample is extracted from the sampling
point in the stack. The sulfuric acid mist (including sulfur trioxide)
and the sulfur dioxide are separated. The sulfur dioxide fraction
is measured by the barium-thorin titration method.
1.2 Applicability. This method is applicable for the determina-
tion of sulfur dioxide emissions from stationary sources. The
minimum detectable limit of the method has been determined to be
3.4 milligrams (nig) of S02/m3 (2.12 x 10"7 lb/ft3). Although no upper
limit has been established, tests have shown that concentrations as high
3
as 80,000 mg/m of SOp can be collected efficiently in two midget impingers
each containing 15 milliliters of 3 percent hydrogen peroxide, at a rate
of 1.0 1pm for 20 minutes. Based on theoretical calculations, the upper
3
concentration limit in a 20-liter sample is about 93,300 mg/m .
Possible interferents are free ammonia, water-soluble cations,
and fluorides. The cations and fluorides are removed by glass wool
filters and an isopropanol bubbler, and hence do not affect the S0«
analysis. When samples are being taken from a gas stream with high
concentrations of very fine metallic fumes (such as in inlets to
control devices), a high-efficiency glass fiber filter must be used
in place of the glass wool plug (i.e., the one in the probe) to remove
the cation interferents.
Free ammonia interferes by reacting with SOp to form particulate
sulfite and by reacting with the indicator. If free ammonia is
G-3
-------
THERMOMETER
PROBE (END PACKED
WITH QUARTZ OR
PYREX WOOL)
en
i
STACK WALL
MIDGET IMPINGERS
MIDGET BUBBLER
SILICA GEL
DRYING TUBE
GLASS WOOL
ICE BATH
THERMOMETER
£=iL
DRY
GAS METER
PUMP
Figure 6-1. S02 sampling train.
SURGE TANK
-------
present (this can be determined by knowledge of the process and
noticing white participate matter in the probe and isopropanol
bubbler), alternative methods, subject to the approval of the
Administrator, U. S. Environmental Protection Agency, are required.
2. Apparatus
2.1 Sampling. The sampling train is shown in Figure 6-1,
and component parts are discussed below. The tester has the
option of substituting sampling equipment described in Method 8
in place of the midget impinger equipment of Method 6. However, the
Method 8 train must be modified to include a heated filter between
the probe and isopropanol impinger, and the operation of the sampling
train and sample analysis must be at the flow rates and solution
volumes defined in Method 8.
The tester also has the option of -'etermining SCL simultaneously
with particulate matter and moisture determinations by (1) replacing
the water in a Method 5 impinger system with 3 percent peroxide solution,
or (2) by replacing the Method 5 water impinger system with a Method 8
isopropanol-filter-peroxide system. The analysis for S0? must be con-
sistent with the procedure in Method 8.
2.1.1 Probe. Borosilicate glass, or stainless steel (other
materials of construction may be used, subject to the approval of
the Administrator), approximately 6-mm inside diameter, with a heating
system to prevent water condensation and a filter (either in-stack or
heated out-stack) to remove particulate matter, including sulfuric
acid mist. A plug of glass wool is a satisfactory filter.
2.1.2 Bubbler and Impingers. One midget bubbler, with
medium-coarse glass frit and borosilicate or quartz glass wool
6-5
-------
packed in top (see Figure 6-1) to prevent sulfuric acid mist
carryover, and three 30-ml midget impingers. The bubbler and
midget impingers must be connected in series with leak-free glass
connectors. Silicone grease may be used, if necessary, to prevent
leakage.
At the option of the tester, a midget impinger may be used
in place of the midget bubbler.
Other collection absorbers and flow rates may be used, but
are subject to the approval of the Administrator. Also, collection
efficiency must be shown to be at least 99 percent for each test run
and must be documented in the report. If the efficiency is found to
be acceptable after a series of three tests, further documentation is
not required. To conduct the efficiency test, an extra absorber must
be added and analyzed separately. This extra absorber must not contain
more than 1 percent of the total SCL.
2.1.3 Glass Wool. Borosilicate or quartz.
2.1.4 Stopcock Grease. Acetone-insoluble, heat-stable
silicone grease may be used, if necessary.
2.1.5 Temperature Gauge. Dial thermometer, or equivalent, to
measure temperature of gas leaving impinger train to within 1°C (2°F).
2.1.6 Drying Tube. Tube packed with 6- to 16-mesh indicating-
type silica gel, or equivalent, to dry the gas sample and to protect
the meter and pump. If the silica gel has been used previously, dry
at 175°C (350°F) for 2 hours. New silica gel may be used as received.
Alternatively, other types of desiccants (equivalent or better) may
be used, subject to approval of the Administrator.
6-6
-------
2.1.7 Valve. Needle valve, to regulate sample gas flow
rate.
2.1.8 Pump. Leak-free diaphragm pump, or equivalent, to
pull gas through the train. Install a small surge tank between the
pump and rate meter to eliminate the pulsation effect .of the
diaphragm pump on the rotameter.
2.1.9 Rate Meter. Rotameter, or equivalent, capable of
measuring flow rate to within 2 percent of the selected flow rate
of about 1000 cc/min.
2.1.10 Volume Meter. Dry gas meter, sufficiently accurate to
measure the sample volume within 2 percent, calibrated at the selected
flow rate and conditions actually encountered during sampling, and
equipped with a temperature gauge (dial thermometer, or equivalent)
capable of measuring temperature to within 3°C (5.4°F).
2.1.11 Barometer. Mercury, aneroid, or other barometer
capable of measuring atmospheric pressure to within 2.5 mm Hg
(0.1 in. Hg). In many cases, the barometric reading may be obtained
from a nearby national weather service station, in which case the
station value (which is the absolute barometric pressure) shall
be requested and an adjustment for elevation differences between
the weather station and sampling point shall be applied at a rate
of minus 2.5 mm Hg (0.1 in. Hg) per 30 m (100 ft) elevation
increase or vice versa for elevation decrease.
G-7
-------
2.1.12 Vacuum Gauge and Rotameter. At least 760 mm Hg (30 in. Hg)
gauge and 0-40" cc/min rotameter, to be used for leak check of the sampling
train.
2.2 Sample Recovery.
2.2.1 Wash Bottles. Polyethylene or glass, 500 ml, two.
2.2.2 Storage Bottles. Polyethylene, 100 ml, to store impinger
samples (one per sample).
2.3 Analysis.
2.3.1 Pipettes. Volumetric type, 5-ml, 20-ml (one per sample),
and 25-ml sizes.
2.3.2 Volumetric Flasks. 100-ml size (one per sample) and 1000-ml
size.
2.3.3 Burettes. -5- and 50-ml sizes.
2.3.4 Erlenmeyer Flasks. 250 mi-size (one for each sample,
blank, and standard).
2.3.5 Dropping Bottle. 125-ml size, to add indicator.
2.3.6 Graduated cylinder. 100-ml size.
2.3.7 Spectrophotometer. To measure absorbance at 352 nanometers.
3. Reagents
Unless otherwise indicated, all reagents must conform to the
specifications established by the Committee on Analytical Reagents of
the American Chemical Society. Where such specifications are not
available, use the best available grade.
3.1 Sampling.
3.1.1 Water. Deionized, distilled to conform to ASTM
specification Dll93-74, Type 3. At the option of the analyst,
G-8
-------
the KMnO. test for oxidizable orgar.ic matter may be omitted when high
concentrations of organic matter are not expected to be present.
3.1.2 Isopropanol, 80 percent. Mix 80 ml of isopropanol with 20
ml of deionized, distilled water. Check each lot of isopropanol for
peroxide impurities as follows: shake 10 ml of isopropanol with 10 ml
of freshly prepared 10 percent potassium iodide solution. Prepare a
blank by similarly treating 10 ml of distilled water. After 1 minute,
read the absorbance at 352 nanometers on a spectrophotometer (Note: Use
a 1-cm path length). If absorbance exceeds 0.1, reject
alcohol for use.
Peroxides may be removed from isopropanol by redistilling or by
passage through a column of activated alumina; however, reagent grade
isopropanol with suitably low peroxide levels may be obtained from
commercial sources.- Rejection of contaminated lots may, therefore, be a
more efficient procedure.
3.1.3 Hydrogen Peroxide, 3 Percent. Dilute 30 percent hydrogen
peroxide 1:9 (v/v) with deionized, distilled water (30 ml is needed per
sample). Prepare fresh daily.
3.1.4 Potassium Iodide Solution, 10 Percent. Dissolve 10.0
grams KI in deionized, distilled water and dilute to 100 ml. Prepare
when needed.
3.2 Sample Recovery.
3.2.1 Water. Deionized, distilled, as in 3.1.1.
3.2.2 Isopropanol, 80 Percent. Mix 80 ml of isopropanol with 20
ml of deionized, distilled water.
6-9
-------
3.3 Analysis.
3.3.1 Water. Deionized, distilled, as in 3.1.1.
3.3.2 Isopropanol, 100 percent.
3.3.3 Thorin Indicator. l-(o-arsonophenylazo)-2-naphthol-3,
6-disulfonic acid, disodium salt, or equivalent. Dissolve 0.20 g
in 100 ml of deionized, distilled water.
3.3.4 Barium Perchlorate Solution, 0.0100 N. Dissolve 1.95 g of
barium perchlorate trihydrate [Ba(C104)2'3H20] in 200 ml distilled water
and dilute to 1 liter with isopropanol. Alternatively, 1.22 g of
[BaCl2'2H20] may be used instead of the perchlorate. Standardize as in
Section 5.5.
3.3.5 Sulfuric Acid Standard, 0.0100 N. Purchase or standardize
to +0.0002 N against 0.0100 N NaOH which has previously been
standardized against potassium acid phthalate (primary standard
grade).
4. Procedure.
4.1 Sampling.
4.1.1 Preparation of collection train. Measure 15 ml of 80
t.
percent isopropanol into the midget bubbler and 15 ml of 3 percent
hydrogen peroxide into each of the first two midget impingers.
Leave the final midget impinger dry. Assemble the train as shown
in Figure 6-1. Adjust probe heater to a temperature sufficient to
prevent water condensation. Place crushed ice and water around the
impingers.
4.1.2 Leak-check procedure. A leak check prior to the
sampling run is optional; however, a leak check after the sampling
run is mandatory. The leak-check procedure is as follows:
G-10
-------
Temporarily attach a suitable (e.g., 0-40 cc/min) rotameter to the
outlet of the dry gas meter and place a vacuum gauge at or near the
probe inlet. Plug the probe inlet, pull a vacuum of at least 250 mm Hg
(10 in. Hg), and note the flow rate as indicated by the rotameter. A
leakage rate not in excess of 2 percent of the average sampling rate is
acceptable. Note: Carefully release the probe inlet plug before
turning off the pump.
It is suggested (not mandatory) that the pump be leak-checked
separately, either prior to or after the sampling run. If done prior to
the sampling run, the pump leak-check shall precede the leak check of
the sampling train described immediately above; if done after the
sampling run, the pump leak-check shall follow the train leak-check. To
leak check the pump, proceed as follows: Disconnect the drying tube
• »
from the probe-impinger assembly. Place a vacuum gauge at the inlet to
either the drying tube or the pump, pull a vacuum of 250 mm (10 in.) Hg,
plug or pinch off the outlet of the flow meter and then turn off the
pump. The vacuum should remain stable for at least 30 seconds.
Other leak-check procedures may be used, subject to the approval of
the Administrator, U.S. Environmental Protection Agency. The procedure
used in Method 5 is not suitable for diaphragm pumps.
G-ll
-------
4.1.3 Sample Collection. Record the initial dry gas meter reading
and barometric pressure. To begin sampling, position the tip of the
probe at the sampling point, connect the probe to the bubbler, and start
the pump. Adjust the sample flow to a constant rate of.approximately
1.0 liter/min as indicated by the rotameter. Maintain this constant
rate (+10 percent) during the entire sampling run. Take readings (dry
gas meter, temperatures at dry gas meter and at impinger outlet and rate
meter) at least every 5 minutes. Add more ice during the run to keep
the temperature of the gases leaving the last impinger at 20°C (68°F) or
less. At the conclusion of each run, turn off the pump, remove probe
from the stack, and record the final readings. Conduct a leak check as
in Section 4.1.2. (This' leak check is mandatory.) If a leak is found,
V *
void the test run or use procedures acceptable to the Administrator to
adjust the sample volume for leakage. Drain the ice bath, and purge the
remaining part of the train by drawing clean ambient air through the
system for 15 minutes at the sampling rate.
Clean ambient air can be provided by passing air through a charcoal
filter or through an extra midget impinger with 15 ml of 3 percent H202.
The tester may opt to simply use ambient air, without purification.
6-12
-------
4.2 Sample Recovery. Disconnect the impingers after purging.
Discard the contents of the midget bubbler. Pour the contents of
the midget impingers into a leak-free polyethylene bottle for
shipment. Rinse the three midget impingers and the connecting
tubes with deionized, distilled water, and add the washings to
the same storage container. Mark the fluid level. Seal and
identify the sample container.
4.3 Sample Analysis. Note level of liquid in container,
and confirm whether any sample was lost during shipment; note
this on analytical data sheet. If a noticeable amount of leakage has
occurred, either void the sample or use methods, subject to the approval
of the Administrator, to correct the final results.
Transfer the contents of the storage container to a 100-ml
volumetric flask and dilute to exactly 100 ml with deionized, distilled
water. Pipette a 20-ml aliquot of this solution into a 250-ml
Erlenmeyer flask, add 80 ml of 100 percent isopropanol and two to four
drops of thorin indicator, and titrate to a pink endpoint using
0.0100 N barium perch!orate. Repeat and average the titration
volumes. Run a blank with each series of samples. Replicate
titrations must agree within 1 percent or 0.2 ml, whichever is larger..
(Note: Protect the 0.0100 N barium perchlorate solution from
evaporation at all times.)
G-13
-------
5. Calibration
5.1 Metering System.
5.1.1 Initia.l Calibration. Before its initial use in the field,
first leak check the metering system (drying tube, needle valve, pump,
rotameter, and dry gas meter) as follows: place a vacuum .gauge at
the inlet to the drying tube and pull a vacuum of 250 mm (10 in.) Hg;
plug or pinch off the outlet of the flow meter, and then turn off the
pump. The vacuum shall remain stable for at least 30 seconds. Care-
fully release the vacuum gauge before releasing the flow meter end.
Next, calibrate the metering system (at the sampling flow rate
specified by the method) as follows: connect an appropriately sized
wet test meter (e.g., 1 liter per revolution) to the inlet of the
drying tube. Make three independent calibration runs, using at least
five revolutions of the dry gas meter per run. Calculate the calibra-
tion factor, Y (wet test meter calibration volume divided by the dry
gas meter volume, both volumes adjusted to the same reference temperature and
pressure), for each run, and average the results. If any Y value
deviates by more than 2 percent from the average, the metering system
is unacceptable for use. Otherwise, use the average as the calibration
factor for subsequent test runs.
5.1.2 Post-Test Calibration Check. After each field test series,
conduct a calibration check as in Section 5.1.1 above, except for the
following variations: (a) the leak check is not to be conducted, (b) three,
or more revolutions of the dry gas meter may be used, and (c) only
two independent runs need be made. If the calibration factor does
G-14
-------
not deviate by more than 5 percent from the initial calibration
factor (determined in Section 5.1.1), then the dry gas meter
volumes obtained during the test series are acceptable. If the
calibration factor deviates by more than 5 percent, recalibrate
the metering system as in Section 5.1.1, and for the calculations,
use the calibration factor (initial or recalibration) that yields the
lower gas volume for each test run.
5.2 Thermometers. Calibrate against mercury-in-glass thermometers.
5.3 Rotameter. The rotameter need not be calibrated, but should
be cleaned and maintained according to the manufacturer's instruction.
5.4 Barometer. Calibrate against a mercury barometer.
5.5 Barium Perch!orate Solution. Standardize the barium perch-
lorate solution against 25 ml of standard sulfuric acid to which 100 ml
of 100 percent isopropanol has been added.
6. Calculations
Carry out calculations, retaining at least one extra decimal figure
beyond that of the acquired data. Round off figures after final calculation,
6.1 Nomenclature.
C<;n = Concentration of sulfur dioxide, dry basis corrected to
bU2
standard conditions, mg/dscm (Ib/dscf).
N = Normality of barium perchlorate titrant, milliequivalents/ml.
P. = Barometric pressure at the exit orifice of the dry gas
oar
meter, mm Hg (in. Hg).
Pstd = standard absolute pressure, 760 mm Hg (29.92 in. Hg).
T = Average dry gas meter absolute temperature, °K (°R).
Tstd = standard absolute temperature, 293° K (528° R).
G-15
-------
m
= Volume of sample aliquot titrated, ml.
= Dry gas volume as measured by the dry gas meter, dcm
(dcf).
'soln
V / td\ = Dry gas volume measured by the dry gas meter,
corrected to standard conditions, dscm (dscf).
= Total volume of solution in which the sulfur dioxide
sample is contained, 100 ml.
= Volume of barium perch!orate titraht used for the
sample, ml (average of replicate titrations).
- Volume of barium perchlorate titrant used for the
blank, ml.
Y = Dry gas meter calibration factor.
32.03 = Equivalent weight of sulfur dioxide.
6.2 Dry sample gas volume, corrected to standard conditions.'
'tb
Vm(std) ' V
where:
K.| « 0.3858 °K/mm Hg for metric units.
= 17.64 °R/in. Hg for English units.
6.3 Sulfur dioxide concentration.
V P
m bar
m
Equation 6-1
soln
'SO,
«z —
m(std)
Equation 6-2
where:
= 32.03 mg/meq. for metric units.
= 7.061 x 10 Ib/meq. for English units.
G-16
-------
7. Bibliography
1. Atmospheric Emissions from Sulfuric Acid Manufacturing
Processes. U.'S. DHEW, PHS, Division of Air Pollution. Public
Health Service Publication No. 999-AP-13. Cincinnati, Ohio. 1965.
2. Corbett, P.P. The Determination of S02 and S(L in Flue
Gases. Journal of the Institute of Fuel. 24:237-243, 1961.
3. Matty, R. E. and E. K. Diehl. Measuring Flue-Gas SO,, and
S03> Power. 1_01_: 94-97. November 1957.
4. Patton, W. F. and J. A. Brink, Jr. New Equipment and
Techniques for Sampling Chemical Process Gases. J. Air Pollution
Control Association. 1_3:162. 1963.
5. Rom, J. J. Maintenance, Calibration, and Operation of
Isokinetic Source-Sampling Equipment. Office of Air Programs,
Environmental Protection Agency. Research Triangle Park, N. C.
APTD-0576. March 1972.
6. Hamil, H. F. and D. E. Camann. Collaborative Study of
Method for the Determination of Sulfur Dioxide Emissions From
Stationary Sources (Fossil-Fuel Fired Steam Generators).
Environmental Protection Agency, Research Triangle Park, N. C.
EPA-650/4-74-024. December 1973.
7. Annual Book of ASTM Standards. Part 31; Water, Atmospheric
Analysis. American Society for Testing and Materials. Philadelphia,
PA. 1974. pp. 40-42.
8. Knoll, J. E. and M. R. Midgett. The Application of EPA
Method 6 to High Sulfur Dioxide Concentrations. Environmental Protection
Agency. Research Triangle Park, N. C. EPA-600/4-76-038. July 1976.
G-17
-------
SLIDE 107-0 NOTES
METHOD —6
Determination of
Sulfur Dioxide Emissions
From Stationary Sources
SLIDE 107-1
PRINCIPLE
A gas sample is extracted from the stack. Sul-
furic acid mist and sulfur dioxide are separated.
Sulfur dioxide is measured by the barium-
thorin titration method.
APPLICABILITY
This method is applicable for determination of
sulfur dioxide emissions from stationary sources.
• minimum detectable limit is 3.4 mg of SO2 per m3
• theoretical calculations indicate the upper con-
centration limit in a 20 liter sample is « 93,300 mg
per m3.
SLIDE 107-2
METHOD 6 INTERFERENCES
1. CATIONS — Removed by glass wool filter and
isopropanol bubbler.
2. FLUORIDES — Removed by glass wool filter and
isopropanol bubbler.
3. FINE METALLIC FUMES — Removed by high
efficiency glass fiber filter.
4. AMMONIA — Use alternative methods (Subject
to Approval of the Administrator).
G-19
-------
SLIDE 107-3
SO2 SAMPLING TRAIN
fl
THERMOME IfcR
MILXHT BU6BLEH
IFRITTEO TIP)
SILICA GtL
DRYING TUBE
(END PACKED
WTTH GLASS WOOL!
STACK
WALL
Hf AUNG
ELEMENT
w
jf!
i
' \
ws*
ICE
BATH
MIL
1 I
•JT
GE
7 \
&$f
T IMPI
1 1
»T
is
' \
*£fc
RS
hri
j
'
if
THtHMOMtTEfi
NfEDLE
VALVE
SURGE TANK
SLIDE 107-4
REAGENTS
Reagents must conform to specifications estab-
lished by American Chemical Society or use best
available grade.
• Check each lot of isopropanol for peroxide impurities.
• Prepare 3% hydorgen peroxide fresh each day.
• Standardize barium perchlorate solution against
standard sulfuric acid to which 100 ml of 100% iso-
propanol has been added.
• Standardize sulfuric acid 0.0100 N against 0.0100 N
sodium hydroxide.
SLIDE 107-5
SAMPLE METER SYSTEM CALIBRATION SETUP
NOTES
MANOMtlER
THEHMOMEIER
THCRMOME lEfl
NEEDLE VALVE
AIR OUTLET
SURGE TANK
WATER OUT
AOJUSI
G-21
-------
SLIDE 107-6 NOTES
THERMOMETER CALIBRATION
• Impinger thermometer should agree to within 2°F
of the standard at both points.
• Dry gas meter thermometer should agree to within
5.4°F of the standard at both points.
ROTAMETER
• calibration not required
• maintain according to manufacturer's instructions
BAROMETER
• calibrate according to procedures in Method 2
SLIDE 107-7
ON SITE SAMPLING
1. Prepare collection train.
2. Conduct pretest leak-check (optional).
3. Run the test.
4. Conduct post test leak-check (mandatory).
5. Purge sample train for 15 minutes.
SLIDE 107-8
SAMPLE RECOVERY
1. Disconnect impingers and discard contents of the
bubbler.
2. Recover contents of the impingers into a leak-free
polyethylene bottle.
3. Rinse impingers and connecting tubes with distilled
water; add washings to sample bottle.
4. Mark liquid level, seal, and identify the container.
G-23
-------
SLIDE 107-9 NOTES
SAMPLE ANALYSIS
1. Check liquid level of the sample.
2. Transfer sample to a 100 ml volumetric flask and dilute to
100 ml with deionized distilled water.
3. Pipette a 20 ml aliquot into a 250 ml erlenmeyer flask.
4. Add 80 ml of 100% isopropanol and two to four drops of
thorin indicator.
5. Titrate to a pink endpoint using 0.0100 N barium perchlorate.
6. Repeat and average titration volumes.
7. Run a blank with each series of samples.
G-25
-------
SECTION H. METHOD 7
Subject Page
1. Method 7—-determination of nitrogen oxide emissions from
stationary sources (taken from Environmental Protection Agency
Performance Test Methods manual) H-3
2. Slides H-19
H-l
-------
METHOD 7--DETERMINATION OF NITROGEN OXIDE
EMISSIONS FROM STATIONARY SOURCES
1. Principle and Applicability
1.1 Principle. A grab sample is collected in an evacuated
flask containing a dilute sulfuric acid-hydrogen peroxide absorbing
solution, and the nitrogen oxides, except nitrous oxide, are
measured colorimetrically using the phenoldisulfonic acid (PDS)
procedure.
1.2 Applicability. This method is applicable to the measure-
ment of nitrogen oxides emitted from stationary sources. The range
of the method has been determined to be 2 to 400 milligrams NO (as
A
NO^) per dry standard cubic meter, without having to dilute the sample.
2. Apparatus
2.1 Sampling (see Figure /-I). Other grab sampling systems or
equipment, capable of measuring sample volume to within +2.0 percent
and collecting a sufficient sample volume to allow analytical reproduci-
bility to within +5 percent, will be considered acceptable alternatives,
subject to approval of the Administrator, U. S. Environmental Protection
Agency. The following equipment is used in sampling:
2.1.1 Probe. Borosilicate glass tubing, sufficiently heated to
prevent water condensation and equipped with an in-stack or out-stack
filter to remove particulate matter (a plug of glass wool is satisfactory
for this purpose). Stainless steel or Teflon tubing may also be used
for the probe. Heating is not necessary if the probe remains dry
during the purging period.
Mention of trade names or specific products does not constitute
endorsement by the Environmental Protection Agency.
H-3
-------
PROBE
^
FLASK VALVE
SQUEEZE BULB
UMP VALVE
PUMP
I
FILTER
GROUND-GLASS SOCKET.
§ NO. 12/5
fv\/ 50mm
110mm'
3-WAY STOPCOCK;
T-BORE. J PYREX.
2-mm BORE. 8-mm OD
GROUND-GLASS CONE.
STANDARD TAPER,
| SLEEVE NO. 24/40
FLASK
FLASKSHIELOL_t\
THERMOMETER
210 mm
GROUND-GLASS
SOCKET. §NO. 12/5
PYREX
•FOAM ENCASEMENT
BOILING FLASK -
2-LITER, ROUND-BOTTOM, SHORT NECK.
WITH J SLEEVE NO. 24/40
Figure 7-1. Sampling train, flask valve, and flask.
-------
2.1.2 Collection Flask. Two-liter borosilicate, round bottom
flask, with short neck and 24/40 standard taper opening, protected
against implosion or breakage.
2.1.3 Flask Valve. T-bore stopcock connected to a 24/40
standard taper joint.
2.1.4 Temperature Gauge. Dial-type thermometer, or other
temperature gauge, capable of measuring 1°C (2°F) intervals from -5
to 50°C (25 to 125°F).
2.1.5 Vacuum Line. Tubing capable of withstanding a vacuum
of 75 mm Hg (3 in. Hg) absolute pressure, with "T" connection and
T-bore stopcock.
2.1.6 Vacuum Gauge. U-tube manometer, 1 meter (36 in.), with
1-mm (0.1-in.) divisions, or other gauge capable of measuring pressure
to within +2.5 mm Hg (0.10 in. hj).
2.1.7 Pump. Capable of evacuating the collection flask to a
pressure equal to or less than 75 mm Hg (3 in. Hg) absolute.
2.1.8 Squeeze Bulb. One-way.
2.1.9 Volumetric Pipette. 25 ml.
2.1.10 Stopcock and Ground Joint Grease. A high-vacuum, high-
temperature chlorofluorocarbon grease is required. Halocarbon 25-5S
has been found to be effective.
2.1.11 Barometer. Mercury, aneroid, or other barometer capable
of measuring atmospheric pressure to within 2.5 mm Hg (0.1 in. Hg).
In many cases, the barometric reading may be obtained from a nearby
national weather service station, in which case the station value
H-5
-------
(which is the absolute barometric pressure) shall be requested and
an adjustment for elevation differences between the weather station
and sampling point shall be applied at a rate of minus 2:5 mm Hg
(0.1 in. Hg) per 30 m (100 ft) elevation increase, or vice versa
for elevation decrease.
2.2 Sample Recovery. The following equipment is required for
sample recovery:
2.2.1 Graduated Cylinder. 50 ml with 1-ml divisions.
2.2.2 Storage Containers. Leak-free polyethylene bottles.
2.2.3 Wash Bottle. Polyethylene or glass.
2.2.4 Glass Stirring Rod.
2.2.5 Test Paper for Indicating pH. To cover the pH range of
7 to 14.
2.3 Analysis. For the analysis, the following equipment is needed:
2.3.1 Volumetric Pipettes. Two 1 ml, two 2 ml, one 3 ml, one
4 ml, two 10 ml, and one 25 ml for each sample and standard.
2.3.2 Porcelain Evaporating Dishes. 175- to 250-ml capacity
with lip for pouring, one for each sample and each standard. The
Coors No. 45006 (shallow-form, 195 ml) has been found to be satisfactory.
Alternatively, polymethyl pentene beakers (Nalge No. 1203, 150 ml), or
glass beakers (150 ml) may be used. When glass beakers are used, etching
of the beakers may cause solid matter to be present in the analytical
step; the solids should be removed by filtration (see Section 4.3).
2.3.3 Steam Bath. Low-temperature ovens or thermostatically
controlled hot plates kept below 70°C (160°F) are acceptable alternatives.
H-6
-------
2.3.4 Dropping Pipette or Dropper. Three required.
2.3.5 Polyethylene Policeman. One for each sample and each
standard.
2.3.6 Graduated Cylinder. 100ml with 1-ml divisions.
2.3.7 Volumetric Flasks. 50 ml (one for each sample and each
standard), 100 ml (one for each sample and each standard, and one for
the working standard KNO-, solution), and 1000 ml (one).
2.3.8 Spectrophotometer. To measure absorbance at 410 nm.
2.3.9 Graduated Pipette. 10 ml with 0.1-ml divisions.
2.3.10 Test Paper for Indicating pH. To cover the pH range of 7
to 14.
2.3.11 Analytical Balance. To measure to within 0.1 mg.
3. Reagents
Unless otherwise indicate:!, it is intended that all reagents
conform to the specifications established by the Committee on Analytical
Reagents of the American Chemical Society, where such specifications are
available; otherwise, use the best available grade.
3.1 Sampling. To prepare the absorbing solution, cautiously add
2.8 ml concentrated HgSO^ to 1 liter of deionized, distilled water. Mix
well and add 6 ml of 3 percent hydrogen peroxide, freshly prepared from
30 percent hydrogen peroxide solution. The absorbing solution should be
used within 1 week of its preparation. Do not expose to extreme heat or
direct sunlight.
3.2 Sample Recovery. Two reagents are required for sample
recovery:
H-7
-------
3.2.1 Sodium Hydroxide (1 Nj. Dissolve 40 g NaOH in deionized,
distilled water and dilute to 1 liter.
3.2.2 Water. Deionized, distilled to conform to ASTM specifi-
cation 01193-74, Type 3. At the option of the analyst,'the KMN04 test
for oxidizable organic matter may be omitted when= high concentrations
of organic matter are not expected to be present.
3.3 Analysis. For the analysis, the following reagents are
required:
3.3.1 Fuming SuIfuric Acid. 15 to 18 percent by weight free
sulfur trioxide. HANDLE WITH CAUTION.
3.3.2 Phenol. White solid.
3.3.3 Sulfuric Acid. Concentrated, 95 percent minimum assay.
HANDLE WITH CAUTION.
3.3.4 Potassium Nitrate. Dried at 105 to 110°C (220 to 230°F)
for a minimum of 2 hours just prior to preparation of standard solution.
3.3.5 Standard KN03 Solution. Dissolve exactly 2.198 g of dried
potassium nitrate (KNO-) in deionized, distilled water and dilute
to 1 liter with deionized, distilled water in a 1000-ml volumetric
flask.
•
3.3.6 Working Standard KNO- Solution. Dilute 10 ml of the
standard solution to 100 ml with deionized distilled water. One
milliliter of the working standard solution is equivalent to 100 yg
nitrogen dioxide (NOp).
3.3.7 Water. Deionized, distilled as in Section 3.2.2.
H-8
-------
3.3.8 Phenoldisulfonic Acid Solution. Dissolve 25 g of pure
white phenol in 150 ml concentrated sulfuric acid on a steam bath.
Cool, add 75 ml fuming sulfuric acid, and heat at 100°C (212°F) for
2 hours. Store in a dark, stoppered bottle.
4. Procedures
4.1 Sampling.
4.1.1 Pipette 25 ml of absorbing solution into a sample flask,
retaining a sufficient quantity for use in preparing the calibration
standards. Insert the flask valve stopper into the flask with the
valve in the "purge" position. Assemble the sampling train as shown
in Figure 7-1 and place the probe at the sampling point. Make sure
that all fittings are tight and leak-free, and that all ground glass
joints have been property-greased with a high-vacuum, high-temperature
chlorofluorocarbon-based stopcock grease. Turn the flask valve and the
pump valve to their "evacuate" positions. Evacuate the flask to
75 mm Hg (3 in. Hg) absolute pressure,, or less. Evacuation to a
pressure approaching the vapor pressure of water at the existing
temperature is desirable. Turn the pump valve to its "vent" position
and turn off the pump. Check for leakage by observing the manometer
for any pressure fluctuation. (Any variation greater than 10 mm Hg
(0.4 in. Hg) over a period of 1 minute is not acceptable, and the
flask is not to be used until the leakage problem is corrected.
Pressure in the flask is not to exceed 75 mm Hg (3 in. Hg) absolute
at the time sampling is commenced.) Record the volume of the flask
and valve (Vf), the flask temperature (T^, and the barometric pres-
sure. Turn the flask valve counterclockwise to its "purge" position
H-9
-------
and do the same with the pump valve. Purge the probe and the vacuum
tube using the squeeze bulb. If condensation occurs in the probe
and the flask"valve area, heat the probe and purge until the con-
densation disappears. Next, turn the pump valve to its "vent" position.
Turn the flask valve clockwise to its "evacuate" position and record
the difference in the mercury levels in the manometer. .The absolute
internal pressure in the flask (P..) is equal to the barometric pres-
sure less the manometer reading. Immediately turn the flask valve to
the "sample" position and permit the gas to enter the flask until
pressures in the flask and sample line (i.e., duct, stack) are
equal. This will usually require about 15 seconds; a longer period
indicates a "plug" in the probe, which must be corrected before
sampling is continued. After collecting the sample, turn the flask
valve to its "purge" position and disconnect the flask from the
sampling train. Shake the flask for at least 5 minutes.
4.1.2 If the gas being sampled contains insufficient oxygen
for the conversion of NO to ML (e.g., an applicable subpart of the
standard may require taking a sample of a calibration gas mixture of NO
in N2), then oxygen shall be introduced into the flask to permit this
conversion. Oxygen may be introduced into the flask by one of
three methods: (1) Before evacuating the sampling flask, flush
with pure cylinder oxygen, then evacuate flask to 75 mm Hg (3 in.
Hg) absolute pressure or less; or (2) inject oxygen into the flask
after sampling; or (3) terminate sampling with a minimum of 50 mm Hg
(2 in. Hg) vacuum remaining in the flask, record this final pressure,
and then vent the flask to the atmosphere until the flask pressure is
almost equal to atmospheric pressure.
H-10
-------
4.2 Sample Recovery. Let the flask set for a minimum of 16 hours
and then shake the contents for 2 minutes. Connect the flask to a mercury
filled U-tube manometer. Open the valve from the flask to the
manometer and record the flask temperature (T^), the barometric
pressure, and the difference between the mercury levels in the
manometer. The absolute internal pressure in the flask (PJ is
the barometric pressure less the manometer reading. Transfer the
contents of the flask to a leak-free polyethylene bottle. Rinse
the flask twice with 5-ml portions of deionized, distilled water
and add the rinse water to the bottle. Adjust the pH to between 9 and
12 by adding sodium hydroxide (1 N_), dropwise (about 25 to 35 drops).
Check the pH by dipping a stirring rod into the solution and then
touching the rod to the pH test paper. Remove as little material as
possible during this step. Mark the height of the liquid level so
that the container can be checked for leakage after transport. Label
the container to clearly identify its contents. Seal the container
for shipping.
4.3 Analysis. Note the level of the liquid in container and con-
firm whether or not any sample was lost during shipment; note this on
the analytical data sheet. If a noticeable amount of leakage has
occurred, either void the sample or use methods, subject to the approval
of the Administrator, to correct the final results. Immediately prior
to analysis, transfer the contents of the shipping container to a 50-ml
volumetric flask, and rinse the container twice with 5-ml portions of
deionized, distilled water. Add the rinse water to the flask and dilute
to the mark with deionized, distilled water; mix thoroughly. Pipette
K-ll
-------
a 25-ml aliquot into the porcelain evaporating dish. Return any
unused portion of the sample to the polyethylene storage bottle.
Evaporate the 25-ml aliquot to dryness on a steam bath and allow to
cool. Add 2 ml phenoldisulfonic acid solution to the dried residue and
triturate thoroughly with a polyethylene policeman. Make sure the solu-
tion contacts all the residue. Add 1 ml deionizerf, distilled water and
four drops of concentrated sulfuric acid. Heat the solution on a
steam bath for 3 minutes with occasional stirring. Allow the solution
to cool, add 20 ml deionized, distilled water, mix well by stirring,
and add concentrated ammonium hydroxide, dropwise, with constant stirring,
until the pH is 10 (as determined by pH paper). If the sample contains
solids, these must be removed by filtration (centrifugation is an
acceptable alternative, subject to the approval of the Administrator),
as follows: filter through Whatman No. 41 filter paper into a 100-ml
volumetric flask; rinse the evaporating dish with three 5-ml portions
of deionized, distilled water; filter these three rinses. Wash the
filter with at least three 15-ml portions of deionized, distilled water.
Add the filter washings to the contents of the volumetric flask and
dilute to the mark with deionized, distilled water. If solids are
absent, the solution can be transferred directly to the 100-ml volumetric
flask and diluted to the mark with deionized, distilled water. Mix
the contents of the flask thoroughly, and measure the absorbance at
the optimum wavelength used for the standards (Section 5.2.1), using the
blank solution.as a zero reference. Dilute the sample and the blank
with equal volumes of deionized, distilled water if the absorbance
exceeds A., the absorbance of the 400 ug N0« standard (see Section 5.2.2).
H-12
-------
5. Calibration
5.1 Flask, Volume. The volume of the collection flask-flask valve
combination must be known prior to sampling. Assemble the flask and
flask valve and fill with water, to the stopcock. Measure the volume of
water to +10 ml. Record this volume on the flask.
5.2 Spectrophotometer Calibration.
5.2.1 Optimum Wavelength Determination. Calibrate the wavelength
scale of the Spectrophotometer every 6 months. The calibration may be
accomplished by using an energy source with an intense line emission
such as a mercury lamp, or by using a series of glass filters spanning
the measuring range of the Spectrophotometer. Calibration materials are
available commercially and from the National Bureau of Standards.
Specific details on the use of such materials should be supplied by the
vendor; general information about calibration techniques can be obtained
from general reference books on analytical chemistry. The wavelength
scale of the Spectrophotometer must read correctly within +5 nm at all
calibration points; otherwise, the Spectrophotometer shall be repaired
and recalibrated. Once the wavelength scale of the Spectrophotometer is
in proper calibration, use 410 nm as the optimum wavelength for the
measurement of the absorbance of the standards and samples.
H-13
-------
Alternatively, a scanning procedure may be employed to determine
the proper measuring wavelength. If the instrument is a double-beam
spectrophotometer, scan the spectrum between 400 and 415 nm using a 200 yg
N0« standard solution in the sample cell and a blank solution in the
reference cell. If a peak does not occur, the spectrophotometer is
probably malfunctioning and should be repaired. When a peak is obtained
within the 400 to 415 nm range, the wavelength at which this peak occurs
shall be the optimum wavelength for the measurement of absorbance of
both the standards and the samples. For a single-beam spectrophotometer,
follow the scanning procedure described above, except that the blank and
4
standard solutions shall be scanned separately. The optimum wavelength
shall be the wavelength at which the maximum difference in absorbance
between the standard and -the blank occurs.
5.2.2 Determination-of Spectrophotometer Calibration Factor KC.
Add 0.0 ml, 2.0 ml, 4.0 ml, 6.0 ml, and 8.0 ml of the KN03 working
standard solution (1 ml = 100 yg N02) to a series of five 50-ml volumetric
flasks. To each flask, add 25 ml of absorbing solution,
10 ml deionized, distilled water, and sodium hydroxide (IN) dropwise
until the pH is between 9 and 12 (about 25 to 35 drops each). Dilute
to the mark with deionized, distilled water. Mix thoroughly and
pipette a 25-ml aliquot of each solution into a separate porcelain
evaporating dish. Beginning with the evaporation step, follow the
analysis procedure of Section 4.3, until the solution has been trans-
ferred to the 100-ml volumetric flask and diluted to the mark. Measure
the absorbance of each solution, at the optimum wavelength, as
i
determined in Section 5.2.1. This calibration procedure must be repeated
H-14
-------
on each day that samples are analyzed. Calculate the spectrophotometer
calibration factor as follows:
A, + 2A, + 3A- + 4A.
K =100 -^ ^75 ^j -9 Equation 7-1
c A^ + A+A+A
H1 + M2 + M3 i- M4
where:
K = Calibration factor
C
A, = Absorbance of the 100-yg N02 standard
A2 = Absorbance of the 200-yg N02 standard
A3 = Absorbance of the 300-yg N02 standard
A. = Absorbance of the 400-vg N02 standard
5.3 Barometer. Calibrate against a mercury barometer.
5.4 Temperature Gauge. Calibrate dial thermometers against
mercury-in-glass thermometers,
5.5 Vacuum Gauge. Calibrate mechanical gauges, if used,
against a mercury manometer such as that specified in 2.1.6.
5.6 Analytical Balance. Calibrate against standard weights.
6. Calculations
Carry out the calculations, retaining at least one extra
decimal figure beyond that of the acquired data. Round off
figures after final calculations.
6.1 Nomenclature.
A = Absorbance of sample.
C = Concentration of N0x as N02> dry basis, corrected to
standard conditions, mg/dscm (Ib/dscf).
H-15
-------
F = Dilution factor (i.e., 25/5, 25/10, etc., required only
if sample dilution was needed to reduce the absorbance
into the range of calibration).
K = Spectrophotometer calibration factor.
m = Mass of NO as N09 in gas sample, yg.
r* Cm.
Pf = Final absolute pressure of flask, mm Hg (in. Hg).
P. = Initial absolute pressure of flask, mm Hg (iri. Hg).
P . = Standard absolute pressure, 760 mm Hg (29.92 in. Hg).
Tf = Final absolute temperature of flask, °K (°R).
T1 = Initial absolute temperature of flask, °K (°R).
T .. = Standard absolute temperature, 293°K (528°R).
V = Sample volume at standard conditions (dry basis), ml.
5C
V.p = Volume of flask and valve, ml.
V = Volume of absorbing solution, 25 ml.
a
2 = 50/25, the aliquot factor. (If other than a 25-ml
aliquot was used for analysis, the corresponding factor
must be substituted).
6.2 Sample volume, dry basis, corrected to standard
conditions.
sc
std
-v
= K] (Vf - 25 ml)
Pi
J-
'i
Equation 7-2
H-16
-------
where:
K.J = °-3858 JSTRq for metric units
= 17.64 . *RUM for English units
in. ng
6.3 Total vg N02 per sample.
m = 2K AF Equation 7-3
Note: If other than a 25-ml aliquot is used for analysis, the
factor 2 must be replaced by a corresponding factor.
6.4 Sample concentration, dry basis, corrected to standard
conditions.
c = K2 T~ Equation 7-4
sc
where:
,3
K2 = 10 TigTrnT for metr1c un1ts
6.243 x 10"5 for English units
7. Bibliography
1. Standard Methods of Chemical Analysis. 6th ed. New York,
D. Van Nostrand Co., Inc. 1962. Vol. 1, p. 329-330.
2. Standard Method of Test for Oxides of Nitrogen in Gaseous
Combustion Products (Phenoldisulfonic Acid Procedure). In: 1968 Book
of ASTM Standards, Part 26. Philadelphia, Pa. 1968. ASTM Designation
D-1608-60, p. 725-729.
3. Jacob, M. B. The Chemical Analysis of Air Pollutants.
New York. Interscience Publishers, Inc. 1960. Vol. 10, p. 351-356.
H-17
-------
4. Beatty, R. L., L. B. Berger, and H. H. Schrenk. Determination
of Oxides of Nitrogen by the Phenoldisulfonic Acid Method, Bureau of
Mines, U. S. Dept. of Interior. R. I. 3687. February 1943.
5. Hamil, H. F. and D. E. Camann. Collaborative Study of Method
for the Determination of Nitrogen Oxide Emissions from Stationary
Sources (Fossil Fuel-Fired Steam Generators). Southwest Research
Institute report for Environmental Protection Agency. Research Triangle
Park, N. C. October 5, 1973.
6. Hamil, H. F. and R. E. Thomas. Collaborative Study of Method
for the Determination of Nitrogen Oxide Emissions from Stationary
Sources (Nitric Acid Plants). Southwest Research Institute report for
Environmental Protection Agency. Research Triangle Park, N. C.
May 8, 1974.
H-18
-------
SLIDE 108-0
METHOD — 7
Determination of
Nitrogen Oxide Emissions
From Stationary Sources
NOTES
SLIDE 108-1
PRINCIPLE
A GRAB sample is collected in an
evacuated flask.
Nitrogen oxides (NOK), except nitrous
oxide, are measured colorimetrically.
APPLICABILITY
This method is applicable for the
measurement of NO, emissions from
stationary sources.
SLIDE 108-2
EVACUATED FLASK SAMPLING TRAIN
PROBE
FUER
EVACUATE
PURGE
SAMPLE
SQUEEZE BULB
FLASK
VALVE THERMOMETER
FLASK SHIELD
PURGE
H-19
-------
SLIDE 108-3 NOTES
SPECIAL ANALYTICAL APPARATUS
• Porcelain Evaporating Dishes
• Spectrophotometer
SLIDE 108-4
SPECIAL REAGENTS
ABSORBING SOLUTION
The absorbing solution consists of concen-
trated H2SO4, deionized distilled water, and 3%
hydrogen peroxide.
STANDARD KNO3 SOLUTION
The standard KNO3 solution consists of 2.198g
of potassium nitrate dissolved in 1 liter of deion-
ized distilled water.
WORKING STANDARD KNO3 SOLUTION
The working standard KNO3 solution consists
of 10 ml of standard solution diluted to 100 ml
with deionized distilled water.
SLIDE 108-5
COLLECTION FLASK CALIBRATION
1. Assemble clean flasks and valves.
2. Fill flask with room temperature water.
3. Measure flask volume to ±10 ml.
4. Number each flask and record volume on flask
or foam case.
5. Only one calibration is required if flasks and
valves are not switched.
H-21
-------
SLIDE 108-6 NOTES
SPECTROPHOTOMETER CALIBRATION
OPTIMUM WAVELENGTH DETERMINATION
Calibrate against a standard with a certified
wavelength of 410 nm every 6 months.
Alternatively, for variable wavelength spectro-
photometers scan the spectrum between 500
and 415 nm using a 200 ng NO2 standard
solution.
When a peak is obtained, the wavelength at
which this peak occurs shall be the optimum
wavelength.
SLIDE 108-7
SPECTROPHOTOMETER CALIBRATION
CALIBRATION FACTOR DETERMINATION
• Prepare calibration solutions containing 0.0,1.0,
2.0, 3.0 and 4.0 ml of the KNO3 working stand-
ard solution.
• Measure absorbance of each solution at the
optimum wavelength.
• Determine calibration factor each day that sam-
ples are analyzed.
SLIDE 108-8
CALIBRATION FACTOR CALCULATION
Ai + 2A2 + 3A3 + 4A4
+ 2
H-23
-------
SLIDE 108-9, NOTES
ONSITE SAMPLING
1. Pipette 24 ml of absorbing solution into a sample
flask.
2. Place probe at sampling point and connect to train.
3. Evacuate flask to 3 in. Hg absolute pressure or less.
4. Turn of pump and check for leaks.
5. Record volume of flask and valve, flask tempera-
ture, and barometric pressure.
6. Purge the probe and vacuum tubing.
SLIDE 108-10
(cont.) ONSITE SAMPLING
7. Measure absolute flask pressure.
8. Turn flask valve to "sample" permitting stack gas to
enter flask.
9. Turn flask to "purge" and disconnect flask from
train.
10. Shake flask for at least 5 minutes.
SLIDE 108-11
ADDING SUPPLEMENTAL OXYGEN
1. Flush cyliner with pure oxygen prior to
evacuation.
2. Inject oxygen into flask after sampling.
3. Terminate sampling with minimum vacuum
of 2 in. Hg and vent flask to the atmosphere.
H-25
-------
SLIDE 108-12 NOTES
SAMPLE RECOVERY
1. Let flask set for minimum of 16 hours.
2. Shake flask for 2 min.
3. Measure absolute pressure in flask.
4. Record flask temperature and barometric pressure.
5. Transfer content of flask to leak-free polyethylene
bottle.
6. Adjust PH to between 9 and 12.
7. Mark liquid level, seal, and identify container.
SLIDE 108-13
ANALYSIS
1. Check liquid level of sample container.
2. Transfer sample to a 50 ml volumetric flask; di-
lute to volume and mix thoroughly.
3. Pipette a 25 ml aliquot into the porcelain evapo-
ration dish and evaporate on a steam bath.
4. Add 2 ml phenoldisulfonic acid solution to dried
residue and triturate.
5. Add 1 ml deionized distilled water, four drops of
concentrated sulfuric acid, and heat on a steam
bath for 3 min.
SLIDE 108-14
(cont.) ANALYSIS
6. Allow solution to cool; add 20 ml deionized distilled
water; add concentrated ammonium hydroxide until
PHislO.
7. Remove solids if necessary.
8. Transfer solution to a 100 ml volumetric flask and
dilute to mark with distilled water.
9. Mix contents of flask thoroughly and measure the
absorbance using the blank solution as a zero
reference.
10. Dilute the sample and blank with equal volumes of
distilled water if absorbance exceeds A4.
H-27
-------
SECTION I. METHOD 8
Subject Page
1. Method 8—determination of sulfuric acid mist and sulfur dioxide
emissions from stationary sources (taken from Environmental Pro-
tection Agency Performance Test Methods manual) 1-1
2. Slides 1-21
1-1
-------
METHOD 8—DETERMINATION OF SULFURIC ACID MIST AND
SULFUR DIOXIDE EMISSIONS FROM STATIONARY SOURCES
1. Principle and Applicability
1.1 Principle. A gas sample is extracted isokinetically from the
stack. The sulfuric acid mist (including sulfur trioxide) and the
sulfur dioxide are separated, and both fractions are measured separately
by the barium-thorin titration method.
1.2 Applicability. This method is applicable for the determi-
nation of sulfuric acid mist (including sulfur trioxide, and in the
absence of other particulate matter) and sulfur dioxide emissions from
stationary sources. Collaborative tests have shown that the minimum
detectable limits of the method are 0.05 milligrams/cubic meter (0.03
x 10~ pounds/cubic foot') for sulfur trioxide and 1.2 mg/m (0.74 x 10
3 ~
Ib'/ft ) for sulfur .dioxide. No upper limits have been established.
Based on theoretical calculations for 200 milliliters of 3 percent
hydrogen peroxide solution, the upper concentration limit for sulfur
33 3
dioxide in a 1.0 m (35.3 ft ) gas sample is about 12,500 mg/m (7.7 x
10 Ib/ft ). The upper limit can be extended by increasing the
quantity of peroxide solution in the impingers.
Possible interfering agents of this method are fluorides, free
ammonia, and dimethyl aniline. If any of these interfering agents are
present (this can be determined by knowledge of the process), alterna-
tive methods, subject to the approval of the Administrator,
U. S. Environmental Protection Agency, are required.
1-3
-------
Filterable participate matter may be determined along with S03 and
S02 (subject to the approval of the Administrator) by inserting a heated
glass fiber filter between the probe and isopropanol impinger (see
*
Section 2.1 of Method 6). If this option is chosen, participate
analysis is gravimetric only; HgSO^ acid mist is not determined separately.
2. Apparatus
2.1 Sampling. A schematic of the sampling train used in this
method is shown in Figure 8-1; it is similar to the Method 5 train
except that the filter position is different and the filter holder does
not have to be heated. Commercial models of this train are available.
For those who desire to build their own, however, complete construction
details are described in APTD-0581. Changes from the APTD-0581 document
and allowable modifications to Figure 8-1 are discussed in the following
subsections.
The operating and maintenance procedures for the sampling train are
described in APTD-0576. Since correct usage is important in obtaining
valid results, all users should read the APTD-0576 document and adopt
the operating and maintenance procedures outlined in it, unless otherwise
specified herein. Further details and guidelines on operation and
maintenance are given in Method 5 and should be read and followed
whenever they are applicable.
2.1.1 Probe Nozzle. Same as Method 5, Section 2.1.1.
t
2.1.2 Probe Liner. Borosilicate or quartz glass, with a heating
system to prevent visible condensation during sampling. Do not use
metal probe liners.
2.1.3 Pi tot Tube. Same as Method 5, Section 2.1.3.
1-4
-------
TEMPERATURE SENSOR
- PROBE
THERMOMETER
CHECK
VALVE
7
REVERSE TYPE
PITOT TUBE
PITOTTUBE
TEMPERATURE SENSOR
ICE BATH IMPINGERS
BY-PASS VALVE
VACUUM
LINE
VACUUM
GAUGE
MAIN VALVE
DKY TEST METER
Figure 8-1. Sulfuric acid mist sampling train.
-------
2.1.4 Differential Pressure Gauge. Same as Method 5, Section
2.1.4.
2.1.5 Filter Holder. Borosilicete glass, with a glass frit
filter support and a silicone rubber gasket. Other gasket materials,
e.g., Teflon or Viton, may be used subject to the approval of the
Administrator. The holder design shall provide a positive seal against
leakage from the outside or around the filter. The filter holder shall
be placed between the first and second impingers. Note: Do not heat
the filter holder.
2.1.6 Impingers--Four, as shown in Figure 8-1. The first and
third shall be of the Greenburg-Smith design with standard tips. The
second and fourth shall be of the Greenburg-Smith design, modified by
replacing the insert with an approximately 13 millimeter (0.5 in.)
ID glass tube, having an unconstricted tip located 13 mm (0.5 in.)
from the bottom of the flask. Similar collection systems, which have
been approved by the Administrator, may be used.
2.1.7 Metering System. Same as Method 5, Section 2.1.8.
2.1.8 Barometer. Same as Method 5, Section 2.1.9.
2.1.9 Gas Density Determination Equipment. Same as Method 5,
Section 2.1.10.
2.1.10 Temperature Gauge. Thermometer, or equivalent, to measure
the temperature of the gas leaving the impinger train to within 1°C
(2°F).
2.2 Sample Recovery.
2.2.1 Wash Bottles. Polyethylene or glass, 500 ml. (two).
2.2.2 Graduated Cylinders. 250ml, 1 liter. (Volumetric flasks
may also be used.)
1-6
-------
2.2.3 Storage Bottles. Leak-free polyethylene bottles,
1000 ml size (two for each sampling run).
2.2.4- Trip Balance. 500-gram capacity, to measure to +0.5 g
(necessary only if a moisture content analysis is to be done).
2.3 Analysis.
2.3.1 Pipettes. Volumetric 25 ml, 100ml.
2.3.2 Burette. 50ml.
2.3.3 Erlenmeyer Flask. 250 ml. (one for each sample blank
and standard).
2.3.4 Graduated Cylinder. 100 ml.
2.3.5 Trip Balance. 500 g capacity, to measure to +0.5 g.
2.3.6 Dropping Bottle. To add indicator solution, 125-ml size,
3. Reagents
Unless otherwise indicated, all reagents are to conform to the
specifications established by the Committee on Analytical Reagents of
the American Chemical Society, where such specifications are available.
Otherwise, use the best available grade.
3.1 Sampling.
3.1.1 Filters. Same as Method 5, Section 3.1.1.
3.1.2 Silica Gel. Same as Method 5, Section 3.1.2.
3.1.3 Water. Deionized, distilled to conform to ASTM specification
01193-74, Type 3. At the option of the analyst, the KMn04 test for
oxidizable organic matter may be omitted when high concentrations of
organic matter are not expected to be present.
1-7
-------
3.1.4 Isopropanol, 80 Percent. Mix 800 ml of isopropanol with 200
ml of deiom'zed, distilled water.
Note: Experience has shown that only A.C.S. grade isopropanol is
satisfactory. Tests have shown that isopropanol obtained from commercial
sources occasionally has peroxide impurities that will cause erroneously
high sulfuric acid mist measurement. Use the following test for
detecting peroxides in each lot of isopropanol: Shake 10 ml of the
isopropanol with 10 ml of freshly prepared 10 percent potassium iodide
solution. Prepare a blank by similarly treating 10 ml of distilled
water. After 1 minute, read the absorbance on a spectrophotometer at
352 nanometers (Note: Use a 1 cm path length). If the absorbance
exceeds 0.1, the isopropanol shall not be used. Peroxides may be removed
from isopropanol by redistilling, or by passage through a column of
activated alumina. However, reagent-grade isopropanol with suitably low
peroxide levels is readily available from commercial sources; therefore,
rejection of contaminated lots may be more efficient than following the
peroxide removal procedure.
3.1.5 Hydrogen Peroxide, 3 Percent. Dilute 100 ml of 30 percent
hydrogen peroxide to 1 liter with deionized, distilled water. Prepare
fresh daily.
3.1.6 Crushed Ice.
3.2 Sample Recovery.
3.2.1 Water. Same as 3.1.3.
3.2.2 Isopropanol, 80 Percent. Same as 3.1.4.
3.3 Analysis.
3.3.1 Water. Same as 3.1.3.
1-8
-------
3.3.2 Isopropanol, 100 Percent.
3.3.3 Thorin Indicator. l-(o-arsonophenylazo)-2-naphthol-3,
6-disulfonic acid, disodium salt, or equivalent. Dissolve 0.20 g
in 100 ml of deionized, distilled water.
3.3.4 Barium Perchlorate (0.0100 Normal). Dissolve 1.95 g of
barium perchlorate trihydrate (Ba(C104)2'3H20) in ZOO ml deionized,
distilled water, and dilute to 1 liter with isopropanol; 1.22 g of
barium chloride dihydrate (BaClg^HgO) may be used instead of the
barium perchlorate. Standardize with sulfuric acid as in Section 5.2.
This solution must be protected against evaporation at all times.
3.3.5 Sulfuric Acid Standard (0.0100 N). Purchase or standardize
to +0.0002 N against 0.0100 N NaOH that has previously been standardized
against primary standard potassium acid phthalate.
4. Procedure
4.1 Sampling.
4.1.1 Pretest Preparation. Follow the procedure outlined in
Method 5, Section 4.1.1; filters should be inspected, but need not be
desiccated, weighed, or identified. If the effluent gas can be
considered dry, i.e., moisture free, the silica gel need not be weighed.
4.1.2 Preliminary Determinations. Follow the procedure outlined
in Method 5, Section 4.1.2.
4.1.3 Preparation of Collection Train. Follow the procedure
outlined in Method 5, Section 4.1.3 (except for the second paragraph
and other obviously inapplicable parts) and use Figure 8-1 instead of
Figure 5-1. Replace the second paragraph with: Place 100 ml of
1-9
-------
80 percent isopropanol in the first impinger, 100 ml of 3 percent
hydrogen peroxide in both the second and third impingers; retain a
portion of each reagent for use as a blank solution. Place about
200 g of silica gel in the fourth impinger.
Note: If moisture content is to be determined by impinger analysis,
weigh each of the first three impingers (plus absorbing solution) to
the nearest 0.5 g and record these weights. The weight of the silica
gel (or silica gel plus container) must also be determined to the nearest
0.5 g and recorded.
4.1.4 Pretest Leak-Check Procedure. Follow the basic procedure
outlined in Method 5, Section 4.1.4.1, noting that the probe heater
shall be adjusted to the minimum temperature required to prevent
condensation, and also that verbage such as, ". . . plugging the
inlet to the filter holder . . . ," shall be replaced by, "... plugging
the inlet to the first impinger . . . ." The pretest leak-check is
optional.
4.1.5 Train Operation. Follow the basic procedures outlined in
Method 5, Section 4.1.5, in conjunction with the following special
instructions. Data shall be recorded on a sheet similar to the one
3
in Figure 8-2. The sampling rate shall not exceed 0.030 m /min
(1.0 cfm) during the run. Periodically during the test, observe the
connecting line between the probe and first impinger for signs of
condensation. If it does occur, adjust the probe heater setting
upward to the minimum temperature required to prevent condensation.
If component changes become necessary during a run, a leak-check shall
1-10
-------
PLANT
LOCATION
OPERATOR
DATE
RUN NO
SAMPLE BOX NO..
METER BOX N0._
METERAH®
CFACTOR
PITOT TUBE COEFFICIENT. Cp
STATIC PRESSURE . nvn H0 tln.Mf)).
AMBIENT TEMPERATURE
BAROMETRIC PRESSURE
ASSUMED MOISTURE, V,
PROBE LENGTH, m (It)
SCHEMATIC OF STACK CROSS SECTION
NOZZLE IDENTIFICATION NO
AVERAGE CALIBRATED NOZZLE DIAMETER, cm (in,).
PROBE HEATER SETTING
LEAK RATE.m3/min,(cftn)
PROBE LINER MATERIAL
FILTER NO/
TRAVERSE POINT
NUMBER
TOTAL
SAMPLING
TIME
(01, min.
AVERAGE
VACUUM
nun Hg
(in.Hg)
STACK
TEMPERATURE
(Tc),
°C (*F) .
VELOCITY
HEAD
(A PS),
mm HjO
(in.H20)
PRESSURE
DIFFERENTIAL
ACROSS
ORIFICE
METER,
mm H20
(in. H20)
GAS SAMPLE
VOLUME,
m3 (h3)
GAS SAMPLE TEMPERATURE
AT DRY GAS METER
INLET,
°C(°F)
Avg
Avg
OUTLET,
°C(°F)
Avg
TEMPERATURE
OF GAS
LEAVING
CONDENSER OR
LASTIMPINGER,
°C (°F)
Figure 8-2. Field data.
-------
be.done immediately before each change, according to the procedure
outlined in Section 4.1.4.2 of Method 5 (with appropriate modifica-
tions, as mentioned in Section 4.1.4 of this method); record all
leak rates. If the leakage rate(s) exceed the specified rate, the
tester shall either void the run or shall plan to correct the sample
volume as outlined in Section 6.3 of Method 5. Immediately after
component changes, leak-checks are optional. If these leak-checks
are done, the procedure outlined in Section 4.1.4.1 of Method 5
(with appropriate modifications) shall be used.
After turning off the pump and recording the final readings at
the conclusion of each run, remove the probe from the stack. Conduct
a post-test (mandatory) leak-check as in Section 4.1.4.3 of Method 5
(with appropriate modifications) and record the leak rate. If the
post-test leakage rate exceeds the specified acceptable rate, the
tester shall either correct the sample volume, as outlined in
Section 6.3 of Method 5, or shall void the run.
Drain the ice bath and, with the probe disconnected, purge the
remaining part of the train, by drawing clean ambient air through the
system for 15 minutes at the average flow rate used for sampling.
Note: Clean ambient air can be provided by passing air through
a charcoal filter. At the option of the tester, ambient air (without
cleaning) may be used.
4.1.6 Calculation of Percent Isokinetic. Follow the procedure
outlined in Method 5, Section 4.1.6.
1-12
-------
4.2 Sample Recovery.
4.2.1 Container No. 1. If a moisture content analysis is to
be done, weigh-the first impinger plus contents to the nearest 0.5 g
and record this weight.
Transfer the contents of the first impinger to a 250-ml graduated
cylinder. Rinse the probe, first impinger, all connecting glassware
before the filter, and the front half of the filter holder with 80 per-
cent isopropanol. Add the rinse solution to the cylinder. Dilute to
250 ml with 80 percent isopropanol. Add the filter to the solution,
mix, and transfer to the storage container. Protect the solution against
evaporation. Mark the level of liquid on the container and identify the
sample container.
4.2.2 Container No. 2. If a moisture content analysis is to be
done, weigh the second and third impingers (plus contents) to the nearest
0.5 g and record these weights. Also, weigh the spent silica gel (or
silica gel plus impinger) to the nearest 0.5 g.
Transfer the solutions from the second and third impingers to a
1000-ml graduated cylinder. Rinse all connecting glassware (including
back half of filter holder) between the filter and silica gel impinger
with deionized, distilled water, and add this rinse water to the cylinder.
Dilute to a volume of 1000 ml with deionized, distilled water. Transfer
the solution to a storage container. Mark the level of liquid on the
container. Seal and identify the sample container.
4.3 Analysis.
Note the level of liquid in containers 1 and 2, and confirm whether
or not any sample was lost during shipment; note this on the analytical
data sheet. If a noticeable amount of leakage has occurred, either void
the sample or use methods, subject to the approval of the Administrator,
to correct the final results.
1-13
-------
4.3.1 Container No. 1. Shake the container holding the
isopropanol solution and the filter. If the filter breaks up,
allow the fragments to settle for a few minutes before removing
a sample. Pipette a 100-ml aliquot of this solution into a 250-ml
Erlenmeyer flask, add 2 to 4 drops of thorin indicator, and titrate
to a pink endpoint using 0.0100 N barium perchlorate. Repeat the
titration with a second aliquot of sample and average the titration
values. Replicate titrations must agree within 1 percent or 0.2 ml,
whichever is greater.
4.3.2 Container No. 2. Thoroughly mix the solution in the
container holding the contents of the second and third impingers.
Pipette a 10-ml aliquot of sample into a 250-ml Erlenmeyer flask.
Add 40 ml of isopropanol, 2 to 4 drops of thorin indicator, and
titrate to a pink endpoint using 0.0100 N barium perchlorate. Repeat
the titration with a second aliquot of sample and average the titration
values. Replicate titrations must agree within 1 percent or 0.2 ml,
whichever is greater.
4.3.3 Blanks. Prepare blanks by adding 2 to 4 drops of thorin
indicator to 100 ml of 80 percent isopropanol. Titrate the blanks in
the same manner as the samples.
5. Calibration
5.1 Calibrate equipment using the procedures specified in the
following sections of Method 5: Section 5.3 (metering system); Section 5.5
(temperature gauges); Section 5.7 (barometer). Note that the recommended
leak-check of the metering system, described in Section 5.6 of Method 5,
also applies to this method.
5.2 Standardize the barium perchlorate solution with 25 ml of
standard sulfuric acid, to which 100 ml of 100 percent isopropanol has
been added.
1-14
-------
6. Calculations
Note: Carry out calculations retaining at least one extra
decimal figure beyond that of the acquired data. Round off figures
after final calculation.
6.1 Nomenclature.
2 2
A = Cross-sectional area of nozzle, m (ft ).
B = Water vapor in the gas stream, proportion by volume.
W5
Cu en = Sulfuric acid (including SO,) concentration, g/dscm
M^iU^ J
(Ib/dscf).
CSQ = Sulfur dioxide concentration, g/dscm (Ib/dscf).
I = Percent of isokinetic sampling.
N = Normality of barium perchlorate titrant, g equivalents/
liter.
Pfaar = Barometric pressure at the sampling site, mm Hg (in. Hg).
P = Absolute stack gas pressure, mm Hg (in. Hg).
P . = Standard absolute pressure, 760 mm Hg (29.92 in. Hg).
T = Average absolute dry gas meter temperature (see
Figure 8-2), °K (PR).
T = Average absolute stack gas temperature (see Figure 8-2),
°
K
T td = Standard absolute temperature, 293°K (528°R).
V = Volume of sample aliquot titrated, 100 ml for H2S
/
and 10 ml for SO^.
V, = Total volume of liquid collected in impingers and
silica gel , ml .
1-15
-------
V = Volume of gas sample as measured by .dry gas meter,
don (dcf).
V (5td)= Volume of gas sample measured by the dry gas meter
corrected to standard conditions, dscm (dscf).
v = Average stack gas velocity, calculated by Method 2,
Equation 2-9, using data obtained from Method 8,
m/sec (ft/sec).
V i - Total volume of solution in which the sulfuric acid
soln
or sulfur dioxide sample is contained, 250 ml or
1000 ml, respectively.
V. = Volume of barium perch!orate titrant used for the
sample, ml.
V.. = Volume of barium perchlorate titrant used for the
blank, ml.
Y = Dry gas meter calibration factor.
AH = Average pressure drop across orifice meter, mm (in.)
H20.
e = Total sampling time, min.
13.6 = Specific gravity of mercury.
60 = sec/min.
100 = Conversion to percent.
6.2 Average dry gas meter temperature and average orifice
pressure drop. See data sheet (Figure 8-2).
6.3 Dry Gas Volume. Correct the sample volume measured by
the dry gas meter to standard conditions (20°C and 760 mm Hg or
68°F and 29.92 in. Hg) by using Equation 8-1.
1-16
-------
. v
"bar * 'iTe' . "W - W13.6)
Equation 8-1
where :
K.J = 0.3858 °K/mm Hg for metric units.
= 17.64 °R/in. Hg for English units.
Note: If the leak rate observed during any mandatory leak-checks
exceeds the specified acceptable rate, the tester shall either correct
the value of V in Equation 8-1 (as described in Section 6.3 of
m
Method 5), or shall invalidate the test run.
6.4 Volume of Water Vapor and Moisture Content. Calculate the
volume of water vapor using Equation 5-2 of Method 5; the weight of
water collected in the impingers and silica gel can be directly
converted to milliliters (the specific gravity of water is 1 g/ml).
Calculate the moisture content of the stack gas, using Equation 5-3
of Method 5. The "Note" in Section 6.5 of Method 5 also applies to
this method. Note that if the effluent gas stream can be considered
dry, the volume of water vapor and moisture content need not be calcu-
lated.
6.5 Sulfuric acid mist (including SCL) concentration.
N (V. - Vtb)
cn = K, * ID a Equation 8-2
UOU. f. - n
2 4 Vm(std)
where:
K2 = 0.04904 g/milliequivalent for metric units,
= 1.081 x 10"4 Ib/meq for English units.
1-17
-------
6.6 Sulfur dioxide concentration.
'v
u (v - V )
w ^Vt vtb; Va
Ccn = K~ n ——' Equation 8-3
S02 3 Vm(std)
where:
- 0.03203 g/meq for metric units.
= 7.061 x 10"5 Ib/meq for English units.
6.7 Isokinetic Variation.
6.7.1 Calculation from raw data.
, . Ts [K4V1c+ (VmV/Tm) (Pbar * AH/13.6)]
60 a vs Ps An
Equation 8-4
where:
K. = 0.003464 mm Hg-m3/ml-°K for metric units.
= 0.002676 in. Hg-ft3/ml-°R for English units.
6.7.2 Calculation from intermediate valuas.
Ts Vstd) Pstd
T5td \ 6 An Ps 60
Equat1on 8'5
where:
Kg = 4.320 for metric units.
= 0.09450 for English units.
1-18
-------
6.8 Acceptable Results. If 90 percent <. I <. 110 percent,
the results are acceptable. If the results are low in comparison
to the standards and I is beyond the acceptable range, the
Administrator may opt to accept the results. Use Citation 4 in
the Bibliography of Method 5 to make judgments. Otherwise, reject
the results and repeat the test.
7. Bibliography
1. Atmospheric Emissions from Sulfuric Acid Manufacturing
Processes. U. S. DHEW, PHS, Division of Air Pollution. Public
Health Service Publication No. 999-AP-13. Cincinnati, Ohio. 1965.
2. Corbett, P. F. The Determination of S02 and SO., in Flue
Gases. Journal of the Institute of Fuel. 24_:237-243. 1961.
3. Martin, Robert M. Construction Details of Isokinetic
Source Sampling Equipment. Environmental Protection Agency. Research
Triangle Park, M. C. Air Pollution Control Office Publication No.
APTD-0581. April, 1971.
4. Patton, W. F. and J. A. Brink, Jr. New Equipment and
Techniques for Sampling Chemical Process Gases. Journal of Air
Pollution Control Association. 1_3:162. 1963.
5. Rom, J. J. Maintenance, Calibration, and Operation of
Isokinetic Source-Sampling Equipment. Office of Air Programs,
Environmental Protection Agency. Research Triangle Park, N. C.
APTD-0576. March, 1972.
6. Hamil, H. F. and D. E. Camann. Collaborative Study of
Method for Determination of Sulfur Dioxide Emissions from Stationary
1-19
-------
Sources (Fossil Fuel-Fired Steam Generators). Environmental Protection
Agency. Research Triangle Park, N. C. EPA-650/4-74-024. December,
1973.
7. Annual Book of ASTK Standards. Part 31; Water, Atmospheric
Analysis, pp. 40-42. American Society for Testing and Materials.
Philadelphia, Pa. 1974.
1-20
-------
SLIDE 109-0
METHOD — 8
Determination of Sulfuric Acid Mist
and Sulfur Dioxide Emissions
from Stationary Sources
NOTES
SLIDE 109-1
PRINCIPLE
A gas sample is extracted isokinetically from the
stack.
Sulfuric acid mist and sulfur dioxide are separated
and measured using the barium-thorin titration method.
APPLICABILITY
This method is applicable for the determination of
sulfuric acid mist emissions from stationary sources.
SLIDE 109-2
METHOD 8 SAMPLING TRAIN
TEMPERATURE
SENSOR
PROBE
PITOT TUBE
TEMPERATURE SENSOR
THERMOMETER
PROBE (r=l
REVERSE TYPE
PITOT TUBE
ORIFICE-INCLINED
MANOMETER
1-21
-------
SLIDE 109-3 NOTES
REAGENTS
Isopropanol which contains peroxide impuri-
ties will cause erroneously high sulfuric acid mist
results.
Test each lot of isopropanol and reject if
absorbance exceeds 0.1.
SLIDE 109-4
CALIBRATION
All components are calibrated using procedures
outlined in Method 5.
SLIDE 109-5
ON SITE SAMPLING
1. Preliminary measurement and set up.
2. Collect stack parameters for setting isokinetic
sampling rate.
3. Set up nomograph and select proper nozzle size.
1-23
-------
SLIDE 109-6 NOTES
MAXIMUM AH CALCULATION
MAX.MUM AH
M
SLIDE 109-7
(cont.) ON SITE SAMPLING
4. Prepare and assemble sampling train.
5. Leak-check sampling train.
6. Run test.
7. Conduct post test leak-check.
8. Purge sampling train.
SLIDE 109-8
SAMPLE RECOVERY
1. Weigh impingers to nearest 0.5 g for moisture
determination.
2. Transfer contents of first impinger to a 250 ml
cylinder; add filter and dilute to mark with 80%
isopropanol. Transfer to container No. 1.
3. Transfer contents from second and third impingers
to a 1000 ml graduated cylinder dilute to volume
with distilled water. Tansfer to container No. 2.
1-25
-------
SLIDE 109-9 NQTES
ANALYSIS
1. Confirm that no leakage occured during transport
of samples.
2. Shake container No. 1 and allow filter fragments to
settle.
3. Pipette a 100 ml aliquot into a 250 ml flask.
4. Add thorin indicator and titrate to a pink end point.
5. Repeat titration. Replicate titrant volumes should
be within 1% or 0.2 ml.
SLIDE 109-10
(cont.) ANALYSIS
6. Thoroughly mix solution in container No. 2.
7. Pipette a 10 ml aliquot into a 250 ml flask.
8. Add 40 ml of isopropanol and two to four drops of
thorin indicator.
9. Titrate to a pink end point.
10. Repeat titration. Replicate titrant volumes should
be within 1% or 0.2 ml.
11. Prepare and titrate blanks in the same manner as
samples.
1-27
-------
SECTION J. HIGHLIGHTS OF EPA METHODS 1-5
This section is under development and will be included in the manual as soon
as it is available.
J-l
-------
SECTION K. SUMMARY OF EQUATIONS
Subject Page
1. Source sampling calculations (taken from the APTI Course 450
manual) K-3
2. Slides K-19
K-l
-------
Source Sampling Calculations
This section presents the equations used for source sampling calculations. These
equations are divided into two parts —equipment calibration, and source test
calculations. Gaseous source test equations are included to aid the source sampler
performing both paniculate and gaseous emissions tests. The purpose of the section
is to give the reader a quick reference to necessary mathematical expressions used
in source testing experiments.
EQUIPMENT CALIBRATION EQUATIONS
Stausscheibe (Type S) Pitot Tube Calibration
Calibration Coefficient (Cp)
Deviation from Average Cp (Leg A or B of Type S tube)
(Eq. 6-2) Deviation = Cp^st(^ - Cp
Average deviation from the mean b (Leg A or B)
(Eq. 6-3) t J, ' ~
Sampling Probe Calibration Developed by Experiment and Graphed for Each
Probe Length
Test Meter Calibration Using Spirometer
Spirometer volume (temperature and pressure correction not necessary for ambient
conditions)
(Eq. 6-4) [Spirometer displacement (cm)] x [liters/cm] = liters volume
Convert liters to cubic feet (ft 3)
Test Meter Correction Factor
Spirometer Standard ft ^
(Eq. 6-5) — = Test meter correction factor
Test meter ft 3
K-3
-------
1l?m
I/ T^
Correct Volume
(Eq. 6-6) [Test meter volume] X [Test meter correction factor] — correct volume
Orifice Meter Calibration Using Test Meter
Test meter volumetric flowrate (Qjn) in cubic feet per minute
(Eq. 6-7) Qm ~ [Test meter (Vf)— Test Meter Vj] X [Test meter correction factor]
Proportionality Factor (Km)
(Eq. 6-8) Km~-
Orifice meter A//@ Flow Rate
0 9244
(Eq. 6-9) 1. English units AH@ = ^
where AH@ = 0.75 cfm at 68°F and 29.92 in. Hg
0.3306
(Eq. 6-9) 2- Metric units AH@ = —
where AH@ = 0.021 m3/min at 760 mm Hg and 20°C
Sampling Meter Console Calibration
Ratio of the accuracy of Console Gas Meter Calibration Test Meter (7).
Tolerance 1± 0.02
(Eq. 6-10) 7 =
Vm Tt
\ 13. 6/
Meter Console Orifice Meter Calibration (AH@)
m
V
T
where K = 0 . 03 1 7 English units
= 0.0012 metric units
0 9244
(Eq. 6-12) 2.
K-4
-------
Source Sampling Nomograph Calibration
Isokinetic AH Equation
isokinetic
6-13)
846.72 D< Af/@ C/
pm
Sampling Nozzle Equation
°-0358
Adjusted C-Factor (Cp)
(Eq. 6-15) C'factor adjusted^ Cfactor Q
Adjusted C-Factor
l-B7/,,+ 18B7,,,/29
(Eq. 6-15) C-factor adjusted ~ C factor Y^T]
SOURCE SAMPLING CALCULATIONS
Method 1 — Site Selection
Equal Area Equation (circular ducts)
(Eq.6-16) =
Equivalent Diameter for a Rectangular Duct
D 2(length) (width)
(Eq. 6-17) E length
Method 2—Gas Velocity and Volumetric Flow Rate
Average Stack Gas Velocity
(Eq. 6-18) Vs^KfiC* \^—^~ V"P ave
Average Dry Stack Gas Volumetric Flow Rate at Standard Conditions
[T
1T~
Pstd,
K-5
-------
Method 3— Orsat Analysis
Stack Gas Dry Molecular Weight
(Eq. 6-20) Md = LMXBX = QA4(%CO2) + 0.32(%02) + Q.2S(%N2 + %CO)
Stack Gas Wet Molecular Weight
(Eq. 6-21) Ms = Md(l - Bws) + 1 8 Bws
Percent Excess Air (%EA)
6-22) %EA= - — - — - — - - xlOO
. o-^> Q 264 (%N^ _ (%()2) + Q5(%co)
Method 4 — Reference Moisture Content of a Stack Gas
Volume Water Vapor Condensed at Standard Conditions (Vwc)
(Eq. 6-23) Vwc = <" "f «° R T»* = K, (Vf- Vd
where Kj = 0.001333 m3/ml for metric units
= 0.04707 ft.3/ml for English units
Silica Gel
(Eq. 6-24) K2 = (wf~ wi) = Vw
• SG
where #2 = 0.001335 m3/gmfor metric units
= 0.04715 ft.3 /gm for English units
Gas Volume at Standard Conditions
m(std)
Moisture Content
V + I
(Eq. 6-26) ^5= y——y
SG
Method 5—Particulate Emissions Testing
Dry Gas Volume Metered at Standard Conditions
Leak Rate Adjustment
N
(Eq. 6-27) Vm =[Vm - (L2 - LJO- E (L,— L^ty- (Lp
i=2
K-6
-------
Standard Dry Volume at Sampling Meter
(Eq. 6-28) V
Isokinetic Variation
Raw Data
(Eq' 6"29> %/= 60 6S VsPsAn
where K3 = 0.003454 mm Hg
ml °K
= 0.002669-'"
ml °R
\
Note: This equation includes a correction for the pressure differential across the
dry gas meter measured by the orifice meter— average sampling run A// readings.
Intermediate Data
. 6-30) %/- 100 - - = K4
PS
where K4 = 4.320 for metric units
0.09450 for English units
Method 8 —Sulfuric Acid Mist and Sulfur Dioxide Emissions Testing
Dry volume metered at standard conditions (see equations in previous sections of
this outline)
Sulfur Dioxide concentration
/., \
solution'
,„ . N(Vt-Vtb)\Vali ot
(Eq. 6-31) N ;
Vm(std)
where K} = 0.03203 g/meq for metric units
= 7.061 xlO~5 Ib/meq for English units
i* c«ov
(Eq.6-32)
Sulfuric acid mist (including sulfur trioxide) concentration
Vm(std)
K-7
-------
where
Isokinetic Variation
Raw Data
(Eq. 6-33)
where
=0.04904 g/meq for metric units
= 1.08X10-4 Ib/meqfor English units
%/=100
6Q0AnvsPs
= 0.003464 mm Hg-m^/ml- °K
= 0.002676 in.Hg-ft^/ml- °R
12
Concentration Correction Equations
Concentration Correction to 12% CO%
(Eq.6-34) ^"
Concentration Correction to 50% Excess Air Concentration
/17 ft ,„
-------
Fw Factor
• When measuring cs and O2 on a wet basis
* &wa ~ moisture content of ambient air
• Cannot be used after a wet scrubber
[20 9 1
:
20.9(1 -B1oa)-%0Zw\
F0 Factor
1. Miscellaneous factor for checking Orsatdata
20.9 Fd 20.B-O9d \°'
(Eq. 6-41) F0= = I on dry basis )
Opacity Equations
% Opacity
(Eq. 6-42) % Opacity =IQQ- % Transmittance
Optical Density
(Eq. 6-43) Optical Density = logiQ \—— . 1
L Opacity J
(Eq. 6-44) Optical Density = log\n
^ \Transmittance]
Transmittance
(Eq. 6-45) Transmittance = e~na
-------
Nomenclature
An — sampling nozzle cross-sectional area
As — stack cross-sectional area
a — mean particle-projected area
Bwm — percent moisture present in gas at meter
^ws ~~ percent moisture present in stack gas
Cp — pitot tube calibration coefficient
Cp(std) — standard pilot-static tube calibration coefficient
cs — paniculate concentration in stack gas mass/volume
cws ~ paniculate concentration on a wet basis mass/wet
volume
Csi9 ~~ paniculate concentration corrected to 12% CC>2
°S50 ~~ Particulate concentration corrected to 50% excess
air
D£ — equivalent diameter
Djj — hydraulic diameter
Dn — source sampling nozzle diameter
E — emission rate mass/heat Btu input
e — base of natural logarithms (lnlO = 2.302585)
%EA — percent excess air
Fc — F-factor using cs and CO2 on wet or dry basis
Fd — F-factor using cs and O2 on a dry basis
Fw — F-factor using cws and O2 on a wet basis
Fo — miscellaneous F-factor for checking orsat data
— pressure drop across orifice meter for 0.75 CFM
flow irate at standard conditions
AH — pressure drop across orifice meter
j — equal area centroid
Kp — pitot tube equation dimensional constant
ri»7j» molr (mini IK)
•
h
English Uniis=85.49 it./sec.
K-10
-------
L — length of duct cross-section at sampling site
f — path length
LI — plume exit diameter
1-2 — stack diameter
m — -mass
M^ — dry stack gas molecular weight
Ms — wet stack gas molecular weight
n — number of particles
NRC — Reynolds number
Q\ — plume opacity at exit
in stack plume opacity
atmospheric pressure
Po — barometric pressure (Po= ^atm)
Pm — absolute pressure at the meter
pmr — Pollutant mass rate
Ps — absolute pressure in the stack
Pst(j — standard absolute pressure
Metric Units = 760 mm Hg
English Units =29.92 in. Hg
Ap — gas velocity pressure
standard velocity pressure read by the standard
pitot tube
gas velocity pressure read by the type "S" pitot
tube
particle extinction coefficient
stack gas volumetric flow rate corrected to
standard conditions
(in. Hg)(ft.3)
R — Gas law constant, 21.83
(lb-mole)(°R)
t — temperature (°Fahrenheit or °Celsius)
Tm — absolute temperature at the meter
Metric Units = °C + 273 = °K
English Units = °F + 460= °R
Ts ~ absolute temperature of stack gas
Tst(j standard absolute tcmju'iniurc
Metric Units = °2()°C -I- 273 = 293°K
English Units = 68°F + 460 = 528°R
Vm — volume metered at actual conditions
^m t(\ ~ volume metered corrected to standard conditions
v.p. — water vapor pressure
vs — stack gas velocity
Volume H£O — Metric units = 0.00134 m3/ml X ml
English units =0.0472 ft.Vmlxml
W — width of the duct cross-section at the sampling site
d — time in minutes
K-ll
-------
Company_
Test Team
Test Date
Observer
SOURCE SAMPLING CALCULATION SHEET
Address
Address
(1) WATER VAPOR VOLUME: (Vw_st(j)
Vw.std - 0.047KV
w-std
(2) DRY GAS VOLUME:
(vm)
m
'm-std
Evaluation Date
Eva!uator
Run
Run
Run
Run
Run
Run
scf
ml
Run
Vn
\
Pt
A^
i
Run
i
i
>ar
{
r
Run
Run
scf,
Run
dry
Run
cf
°R
"Hg.
"H20
K-12
-------
(3) MOISTURE CONTENT: (B )
B =
x 100
'w-std
'm-std
Run
Run
-
Run
scf
scf
B =
w
Run
Run
Run
(4) GAS ANALYSIS:
cc
Run
Run
Run
%C02 x 0.44 =
%02 x 0.32 =
%CO x 0.28 =
%N2 x 0.28 =
Md =
Run
Run
Run
#/#-mole, dry
(5) GAS MOLECULAR WEIGHT: (Mg)
B B
s " v dM
" 100' IOMOO;
Run
Run
Run
#/#-mole, wet
K-13
-------
(6) ABSOLUTE STACK PRESSURE (P$)
, . stat
bar 13.6
(7) STACK VELOCITY: (V,.)
Run
Run
Run
"Hg.
s-avg
s-avg
Run
titTo) |/_
* p'avgf Tf
Vavq
CP
(VEjTjavg =
s-avg
Ps
Hs
Run
Run
Run
Run
Run
fps
°R
"Hg.
#/#-mole
K-14
-------
(8) ISOKINETIC VARIATION: (I)
1.667(T.. )[0.00267(V
I =
Vs-a,gs
S avQ.
>'e>
I =
(9) PARTICULATE CONCENTRATION: (c)
Run
T —
s-avg ~
£
~
vs-avg
Ps
0
A
n
Y
Run
=
Run
Run
Run
Run
%
°R
ml
cf
fps
"Hg.
min.
sq. ft
A
B
R
M =
n
V =
m-std
= A / B =
Run
Run
Run
mg.
scf
c = 35,310(R)
= 0.0154(R)
-6,
= 2.205 x 10 (R) =
Run
Run
Run
micrograms/cubic meter, normal
grains/std. cubic foot
pounds/std. cubic foot
K-15
-------
(10) VOLUMETRIC FLOW RATE (Actual ):(Q)
For circular ducts
For rectangular ducts
Q = (D(W)(Vs_avg) x 60
Run
V
s-avg
Ds =
L
W
Run
Run
Run
Run
acfm
Run
fps
ft.
ft.
ft.
(11) VOLUMETRIC FLOW RATE (Standard Conditions): (Qstd)
B
17.65(1 - -
*std
s-avg
Run
Run
B
w
Q
Ps -
s-avg
Run
«
Run
;cfm, dry
Run
Run
%
acfm
"Hg.
°R
K-16
-------
(12) POLLUTANT MASS RATE: PMR
PMRc = 1.323 x 10"4(R)(Qstd)
Run
Run
Run
scfm
PMR =
Run
Run
Run
Ibs/hr
For circular ducts
PMRa =
a
1.323 x 10~4(Mn)
e
For rectangular ducts
1.323 x 10"4(Mn)(L)(W)
= 6 A
n
PMR. =
Run
Run
M =
n
9 =
Ds =
D =
n
L =
W =
A =
n
Run
F
tun
Ibs/hr
Run
Run
mg.
nrin.
ft.
ft.
ft.
ft.
sq. ft
K-17
-------
(13) ISOKINETIC CHECK:
I = PMRa/PMR x 100 =
a C
Run
Run
Run
(14) "F" FACTOR CALCULATION
E = 2.205 x 10'6(R)(F)(L;20-9
R =
F =
V
Run
Run
Run
E =
lun
Run
Run
Ib/MM Btu
K-18
-------
SLIDE 151-0 NOTES
SUMMARY OF EQUATIONS
EPA REFERENCE METHODS 1-5
SLIDE 151-1
ABSOLUTE STACK PRESSURE (PJ
P__
-
stat
SLIDE 151-2
STACK VELOCITY (V.)
V — RR
Vs.avg - 8b.
K-19
-------
SLIDE 151-3 NOTES
DRY MOLECULAR WEIGHT (MJ
Md = 0.44 (% CO2) + 0.32 (% O2)
d . 2 . 2
0.28 (% N2 + % CO)
SLIDE 151-4
MOLECULAR WEIGHT OF STACK GAS (MJ
Ms = Md (1 - Bws) + 18 (Bws)
SLIDE 151-5
PERCENT EXCESS AIR (EA)
%EA =
% O, - 0.5% CO 1
N2 - (% 02 - 0.5% CO) J
0.264% m2
K-21
-------
SLIDE 151-6
VOLUME OF WATER VAPOR CONDENSED (V^^J
NOTES
w«std>
(V,-VjlPwRT^
P^M.
std twlw
K, (V, - Vc)
SLIDE 151-7
MOISTURE CONTENT
B
V
*wc(std) ~r ^m(std)
SLIDE 151-8
SAMPLE GAS VOLUME (Vmstd)
V m O+H V i
mstd
m
PK« +
bar
.AH
13.6
K1VmY
1 std
Phar + (AH/13.6)
m
K-23
-------
SLIDE 151-9
NOTES
LEAK RATE CORRECTION
CASE NO. 1
Vm- [(Lp-La)6]
SLIDE 151-10
LEAK RATE CORRECTION
CASE NO. 2
Vm - (L, - LJ6, - 2 (L, - La)62 - (Lp - La)0
SLIDE 151-11
STACK GAS FLOW RATE (Q5)
0, - As x Vs x 60
K-25
-------
STTDE 151-12 NOTES
STACK GAS FLOW RATE AT STANDARD CONDITIONS (Q.,fcU1))
_Ps_ Jstd f 1 _ g )
3 T * "•'ws'
std ' s
SLIDE 151-13
ISOKINETIC VARIATION (I)
FROM RAW DATA
_ f, [K3 V,c + (VJTJ (Pbar + AH/13.6)]
606VSPSAN
SLIDE 151-14
ISOKINETIC VARIATION (I)
FROM INTERMEDIATE VALUES
TV P
T _ ' s v m(std) ' std
Tstd Vs 0 An Ps 60 (1-Bws)
K-27
-------
SLIDE 151-15 NOTES
PARTICULATE CONCENTRATION^,)
GRAINS PER SCF
C. = 0.154 M"
C. = 2.2x10 6
V
Ibs per hour
Mn
Vm(std)
SLIDE 151-16
ACETONE BLANK CONCENTRATION (CJ
Ca~V_P
a a
SLIDE 151-17
ACETONE WASH BANK (WA)
wa = c, v_ P
a w aw " a
K-29
-------
SECTION L. MISALIGNMENT OF PITOT TUBE
Subject Page
1. Pitot tube errors due to misalignment and nonstreamlined flow L-3
2. Slides L_7
L-l
-------
Phot Tube Errors Due to Misalignment
and Nonstreamlined flow *
D. JAMES GROVE and WALTER S. SMITH
Although the pitot tube is the tool most commonly used for measuring velocities in stacks and ducts, it is also the
tool most commonly misused. In order to use the tube properly, the stack sampler must first gain a better under-
standing of ihe errors which occur when it is misused. This paper will be limited to a discussion of the errors caused by
misaiignment of the pitot tube with respect to the flowing gases, and errors caused by the non-streamlined flow of the
gases. Although the errors discussed here are common to all pitot tubes, data will be presented only for "S" type pitot
tubes, since they are the type most commonly used. The two basic types of pitot tube misalignment are shown in
Figure 1. From.experimental data taken in a 12" diameter demonstration duct, with velocities on the order of 20 feet
per second, the magituda of the error in the velocity measurement is given in Figures 2 and 3. The error is plotted as a
CASE A
CASEB
Flgur» 1. Typw of pitot tub* miMl!gnnwnt.
function of the angle (0 or 0) of misalignment, and it is the error in the velocity, not the velocity pressure lAp). To get
the approximate error in the Ap. the errors from the graph would have to be multiplied by two.
From Figure 2 we can draw several conclusions. Contrary to popular opinion, the alignment which gives the highest
reading docs not indicate the direction of flow. The direction of flow is indicated by the inflection point, or by a 90°
rotation from the alignment which yields a zero velocity pressure. Also important is that misalignment of up to 50° will
result in only a 5% error in velocity.
Figure 3 offers one immediate conclusion, that the error is not symmetrical on either side of the correct alignment.
When the pitot tube is pointed into the flow, the velocities measured are generally too high, and when the pitot tube.is
pointed away from the flow, the velocities measured are too low. These errors are also of a much larger magnitude than
those encountered from case A.
If a pitot tube is aligned so that neither $ nor $ are zero (case A and B simultaneously), the resulting errors would be
approximately the sum of tha two individual errors.
* Taken from Stack Sampling News, Vol. 1, Number 5. Nov. 1973.
L-3
-------
3
-
•
,d<
30
H
/
'
jgr
/
/
5
1
ee
-(
H
I
1
',
5
30
/
I
J
/
P
\
'-
V
40
fi>
_f
£>—
>0
\j
+6
7
J
-6
-1
-1
-2
-J
-3
/TV
>--
>0
srr
or
>
+4
a
0s-
K
^
*<
\
I
~\
iO
«l
I
\
\
.
\
\
I
I
•
*£
1
10
fiffurt 2. Vilocity trrort from ettt A Miulignmcnt.
I I
+12
—r $,degrees
+6 •:
-80 t
-60
-40
-20
+20
+60
+80
z
-6
-12
&
I
r
•18
-I'
-30
T
-36 % error -
Vttodty trrort from cue B
L-4
-------
Now that the errors due to misalignment are apparent, velocity measurements in non-streamlined flow should be
considered. Tho primary use of the pitot tube by the stack sampler is measuring the velocity at several points on the
(tack cross-section which represent the average face velocity of the pases. The normal procedure is to divide the suck
cross-section into equal areas, and make velocity measurements at the centroid of each of these areas. In order to obiain
an average face velocity, the sampler sums the velocities at each point and divides by the number of points (equal
areas). Note that in this procedure, the sampler assumes that the gases are flowing perpendicular to each of these equal
areas. If this is not the case, the sampler should determine the upward (parallel to the stack walls) vector of the velocity
at each area.
.t should be considered what errors result when the pitot tube is placed properly with respect to the stack, but the
gases are traveling at an angle to the stack wall (an an angle 4> or & with respect to the pitot tube). The curves in Figures
2 and 3 show that when the pitot tube is not aligned properly with the flow, the velocity reading is neither the velocity
vector in the direction of flow, nor the velocity vector perpendicular to the tube. The curves do give us the error
between the velocity readings and the velocity vector in the direction of flow for a given value of 0 or S. Also the
velocity vector parallel to the stack walls will be cos i or cos 8 times the velocity vector in the direction of flow.
Consequently, the error between the velocity readings and the velocity vector parallel to the stack walls will be a
combination of error in Figures 2 or 3 and the cosine of the angle between the flow and the pitot tube. This combined
error is shown in Figure 4 for case A and Figure 5 for case B. Keep in mind that these are errors in the velocity, not the
Ap.
The most important conclusion to draw from these curves (Figures 4 and 5) is that if the pitot tube is aligned
properly with respect to the stack, regardless of the direction of flow, the resultant velocity readings will be either close
to correct or too high. There will never be a large error on the low side.
Figun 4. Velocity eiron from cut A flow misalignment.
There are two predominant cases of non-streamlined flow which occur in stacks and ducts that should be discussed
in more detail. The first of these, which is by far the most common case, is after a bend or an elbow in the duct. Tho
resulting flow is shown in Figure 6.
In attempting to measure the upward vector of the velocity, the error (with the pitot tube properly aligned with
ritpect to the stack) will depend on which of the three ports shown (X, Y, and 2) are used. Port Y will give errors
L-5
-------
corresponding to Figure 4. Port X will givo errors corresponding to trie left half of Figure 5, while Port Z corresponds to
the right half of Figure 5. Ron X is the only port which gives velocity reading} >t all clow to the upward velocity
vector, regardless of the angle.
\
\
-60
m
3^
-60
-40
^©-f —
-(•^
-20
.^Wi
-0
— -
X
^*~*
+150
- % error -
+100
+5
-
^
- -25
^
7
^+20
d
k®
1
/
/
,-
/
1
X
T
/
I/
2
2
1
+40
41
+60.
+80
, degrees ^
•i^^—
Flgurt & Velocity •iron from CM* B flow mitalignmcnt.
The second important case of non-streamlined flow is called tangential or cyclonic flow, which normally occurs after
a cyclone or a cyclonic scrubber. The resulting flow is shown in Figure 7. There are only two velocity vectors, axially
and tangentiaily (move radially), so that regardless of which port is used (X1, Y'. or Z'), the error always corresponds to
that in Figure 4. The larger the tangential vector, the larger the error.
6
) O (z
X1
fiyurt 6. Flow «f t»f a tend or *n elbow.
flgun 7. TengentUI or cyclonic flow.
1-6
-------
SLIDE 152-0
PITOT TUBE
MISALIGNMENT
NOTES
SLIDE 152-1
1-7
-------
SLIDE 152-2
NOTES
SLIDE 152-3
L-9
-------
SLIDE 152-4
NOTES
SLIDE 152-5
VELOCITY ERROR
VS
PITCH ANGLE FOR AN S-TYPE PITOT TUBE
6.1 m/sec
, degrees
J I
L-ll
-------
SLIDE 152-6
FLOW AFTER BEND OR ELBOW
NOTES
Y
xt> o dz
SLIDE 152-7
TANGENTIAL OR CYCLONIC FLOW
Y1
TOP
VIEW
L-13
-------
SLIDE 152-8
NOTES
VELOCITY ERRORS FROM TYPE A
FLOW MISALIGNMENT
+ 150 -
+ 100
+ 50
% VELOCITY
ERROR
-80
-60
-40 -20
+ 20
+ 40 +60 +80
SLIDE 152-9
VELOCITY ERRORS FROM TYPE B
FLOW MISALIGNMENT
+ 150
+ 100
+ 50
-40 -20
J L
_ % VELOCITY
ERROR
-80 -60
-------
SECTION M. ISOKINETIC SAMPLING AND BIASES FROM NONISOKINETIC SAMPLING
Subject Page
1. A method of interpreting stack sampling data M-3
2. Slides M-13
M-l
-------
A Method of Interpreting Suck Sampling Data*
W. S. Smith, ft. T. Shigehara. andW. F. Todd
Engineering Section
Institute for Air Pollution Training
Office of Manpower Development
National Air Pollution Control Administration
Public Health Service
Environmental Health Service
U.S. Department of Health. Education and Welfare
INTRODUCTION
In order to obtain an average pollutant concentration (cj, two basic quantities are required: (1) total quantity of
pollutant (pmit) emitted from the stack per time period (0t), and (2) total quantity or volume of effluent gas (V,t)
emitted from the stack for the same time period (6t). In equation form:
The objective of the stack sampler is to obtain these two basic quantities, pmit and Vit. Since they generally cannot
be measured in their entirety, multiple measurements are made in order to estimate them. The general approach is to
divide the stack cross section into a number of equal areas (N.) and to traverse the cross section by sampling at the
midpoint or centroid of each equal area for equal lengths of time (0,). The sample is extracted at a regulated rate,
isokinetically for particulates, and proportionally for gaseous pollutants.
The sampler's first assumption is that the sample extracted at the midpoint of the elemental area (Ae) is representative
of that area; i.e., the concentration entering the sampling nozzle (cn) is equal to the average concentration of the elemental
area (cc). The second assumption is that the average concentration (cn) obtained from the sampling train, upon traversing,
is equal to the average stack concentration (c,) as defined by Equation 1. It has been pointed out that the correctness of
the above assumptions is dependent on the time and cross-sectional variation of the pollutant concentration [1]. Whether
or not the proper sampling approach was used in obtaining a representative sample concentration of the source, however,
an evaluation of the stack sampling data can still be made to determine if proper sampling techniques were employed, i.e.,
isokinetic sampling rates for particulates and proportional rates for gases.
Hemeon and Haines [2] in 1954 pointed out two methods of calculating dust concentrations, and Badzioch [3, 4]
expounded upon them in 1958 and 1960. For the purpose of this paper, these methods will be referred to as: (1) the
ratio-of-area and (2) the sample-concentration calculation methods. Both utilize the inertial properties of the particles. In
essence, the above authors have said that, when anisokinetic conditions exist, the ratio-of-area calculation method gives
better accuracy for very large or coarse particles, and the sample-concentration calculation method gives better accuracy
for gases or fume-like (very small) particles. The decision of which method to use is based on prior knowledge of the
particle size distribution.
The purpose of this paper is to show how the two methods can be used to interpret stack sampling data.
GENERAL PRINCIPLES
THEORY OF SAMPLING PROCEDURE AND CALCULATIONS
Consider a particulate sampling train with a nozzle of size An extracting a sample from an elemental area (Ae) for a
time period '(0J. whore 00 is the total sampling time (dt) divided by the total number of elemental or equal areas (Ne).
When isokinetic conditions exist, i.e., the stack velocity at the centroid of the elemental area (v,e) is equal to the nozzle
velocity (vns), the sampling train automatically integrates the instantaneous pollutant mass emission rate into the probe
nozzle (pmrn.) ovor the time period (0,}. Mathematically:
* Taken from Stack Sampling News, Vol. 1, No. 2, August 1973.
M-3
-------
mn. = I Pmrn.d0. = / Anvn.cn.d0.
0, 0t
(2)
where mna is the pollutant mass collected by the sampling train during 'Jme 09.
A sample traverse sums the individual mn.'s for all the elemental areas or:
(3)
where mnt is the pollutant mass collected by the sampling train during the total sampling time (0t). Hereafter, for
simplicity, the summation sign (S) will denote the summation from e=1 to e=N,.
The pollutant mass (mnt) is one of the actual data that the sampler receives. This datum (mnt) is used to estimate the
average pollutant mass emission rate (pmr,) from the stack. This can be accomplished in the following manner.
Dividing Equation 2 through by An yields:
For isokinetic conditions (vn. = VM), using the assumption that the sample concentration is representative of the
elemental area concentration <€„. ** c,.), it follows that the pollutant mass from the elemental area (mM/A.) ;s-
7=- -
(4)
A.
!A7'
Dividing Equation 4 by 0. yields the average pollutant mass emission rate (pmrt.) from the elemental area (A.) :
_ m«« A. mn.
pmr.. =• ~~~" —~ ----- f 5\
^ An 0. tb)
The sample traverse yields the average pollutant mass rate from the entire stack:
_ „ • A-mn. A.
. pmr, - S pmrM = S -—•—=-—- Lmnt (6)
An A. Anfl.
Substituting Equation 3 and using 0, = 0t/N8 and A, = A,N.r Equation 6 can be rewritten as:
_ mnt A,
8: - (7)
M-4
-------
Equation 7 is the retio-of-orea method of calculation.
The second method of estimating prnr, is to use the average sample concentration (cj and the average stack velocity
(v,). Notice how this is effected.
The sample volume (Vn.) that the sampling train extracts during time (0.) from the elemental area (A.) is also an
integrated volume. Mathematically:
A cample traverse again yields the sum of the volumes defined by Equation 8.
Vn, = SVn.-2/ AnVn.d0. (9)
e«
By combining Equations 3 and 9, the average sample concentration can be calculated.
77- (10)
vnt
It is then assumed that c~n ="c,.
If velocity measurements are taken simultaneously with the pollutant sample and it is assumed that the average stack
velocity (v() = \fr v"M/N,, "cn andV, can be used to determine prnF,:
_
— -v,A, (11)
Equation 11 is the sample-concentration method of calculation.
The same analogy can be applied to pollutant concentration instead of the pollutant mass emission rate of Equation 7
and Equation 11. yielding the following:
T»nt
"c, =* — Sample-Concentration Method ( 1 2)
m,
nt
* 0«v.Ar
Ratio-of-Area Method' (13)
Equations 12 and 13 are the equations used by Hemeon and Haines, and by Badzioch. For the sake of brevity, the ensuing
discussion will be limited to Equations 7 and 11.
At this point. Equations 7 and 11 will be redefined and summarized to distinguish between the two methods as
follows:
mnt A.
pmr «=
fit Afl (7)
Tint _
pmre ™ v,A, (11)
Vnt
M-5
-------
where: pmr, = pollutant mass emission rate calculated on a
ratio-of-area basis
pmre = pollutant mass emission rate calculated on a
sample concentration basis
mnt = pollutant mass collected by the sampling train
in total sampling time (0t)
A, = area of stack cross section
An = area of sampling nozzle
Vnt — actual metered sample gas volume corrected to
stack conditions
7, = average measured stack gas velocity at stack
conditions
DETERMINATION OF AVERAGE SAMPLING RATE
The ratio Vn/Vj is the ratio of isokinetic conditions on an average. By taking the ratio of pmr. to pmrc, and noting
pmr, vnt vn
pnvc ntav.A, An0t7. V,
Vnt
We see that pmr./pmra is also a measure of the degree of isokinetic conditions on an average. Summarizing in Table 1
as follows:
Tablt 1. Amngt Sampling Reta
Ratio, Ayarage
pmr, / pmr0 Condition
1 Isokinetic
< 1 Undarisokinatic
> 1 Overwokinatic
Equation 14 says: (1) that only when isokinetic conditions exist will pmr, = pmre, (2) that in order to determine the
ratio pmr,/pmrc. it is necessary only to know Vntl 0t, An, and 7,, and (3) that the ratio prn7./pmrc is not a function of
the characteristic of the pollutant collector (an independent evaluation must be made on the efficiency of the collector).
DISCUSSION AND CATEGORIES OF SAMPLING RATES
It must be understood what the possibilities of Table 1 mean. When pmr,/prnrc -=fe 1. it means that the results are
definitely questionable. When pmr,/pmrc = 1, it means that isokinetic conditions were maintained on an average during
the sampling period, but does not necessarily mean that the results are valid. The integrated volumes can be obtained by
sampling at the average stack velocity (v,) while traversing such that7n =7t. But because of variation of velocity over the
cross section, there are times when anisokinetic conditions will exist. The same situation could arise due to fluctuation of
velocity. Since
M-6
-------
when vn =7S, it should be obvious that the criteria of Table 1 are valid only if Vnt and v. are obtained independently; i.e.
Vnt » not calculated using Equation 15. or vice versa.
Use of Equation 15 is equivalent to the ratio-of-area method of calculation as this would make pm?c = pmr.. Such
sampling trains using only a rate meter (orifice, rotameter. cyclone, etc.) or only a null-balance nozzle are not amenable to
the criteria of Table 1 as they are not subject to any cross-check at all. For example, errors could be introduced through:
1. Miscalculation in the sampling rate leading to an improper meter setting.
2. Careless meter of equipment adjustments.
3. Improper calibration of meters or of null-balance nozzles.
4. Misuse through pure ignorance of the operating principles of the rate meters or null-
balance nozzles.
In the above conditions, isokinetic rates can be claimed without dispute.
An evaluator can only:
1. Rely on reputation of the sampler.
2. Critically examine the procedure.
3. Check the results using a material balance.
4. Rely on past data whose reliability may also be questionable.
All this points to the fact that a volumetric device such as a dry gas meter is a must in a sampling train if any
interpretation is to be made. An independent velocity reading (pitot tube), preferably simultaneous with sampling. Is also a
must
With the understanding that the ratio pmra/pmrc be a function of the independent measurable quantities (Vnt, 0t.
An, and7,. the different sampling conditions can be categorized as shown in Table 2
Table 2, Sampling Rate Cattgoriet
Casol: pnv,/pmre m 1 or7n
Casa 2: pmra/pmrc * 1
ERRORS IN PROPORTIONAL ANISOKINETIC CONDITIONS
Before any guidelines can be established, it must be understood how anisokinetic conditions affect the results because
the practical situation says that Case 2 is the more .general situation. Going back to Equation 3, it can be seen that this case
(7n T£"V,) could affect the amount of pollutant collected.
(3)
The general premise is that when vn = v,. then c,, = c.; but when vn ¥= vs. cn =£ c, except when sampling for gases and
small particles. Thus the amount of pollutant collected by the sampling train depends on vn/v. and the variation of c,. The
degree of deviation from the time value (c,) depends on the method of calculation and- the particle size distribution.
Hemeon and Haines [2] and Badzioch [3, 4] illustrated the effect under steady state conditions (c, = constant) of
particle sizes depending on the calculation methods when only large particles and only small particles were present Figures
M-7
-------
1 and 2 illustrate this. Figure 3 is a combination of Figures 1 and 2, and Table 3 summarizes the biases relative to the true
pmr, [5].
1.6
1.4
1.2
1.0
OJ
0.6
0.4
p.we (SMALL)
I
0.4
US
8.8 LO 1.2
RATIO OF ISOKINETIC,
1.4
Figun 1. Error* due to anisokiiwtic conditions (•mall partidm).
Table 3. Constant Proportion*! Condition
Rttia
pmra/piTirc
Condition
Bias relative to
true pmr,
pcnra ~~
Itokinatic
Underisokinetic
Ov«r iso kinetic
According to Figure 1. when only small particles exist (including gaseous pollutants), the sample-concentration
method of calculation gives accurate results; according to Figure 2, when only large particles exist, the ratio-of-area
calculation method gives the most accurate result under anisokinetic conditions. Figure 3 shows the maximum deviation
from the true value [as marked by pmr, (small) and pmre (large)] that could possibly occur if constant proportional
conditions are maintained.
Unfortunately, the two extremes, all large particles or all small particles, do not often occur. A mixture of large and
small particles is the more general case. The dotted line in Figure 3 shows the case where 50 percent by weight are small
and 50 percent are large particles. A mixture of different size particles, then, only tends to decrease or shrink the outer
M-8
-------
L2
g LO
T—"I
0.
0.4
O.S
1.4
M LO L2
RATIO OF ISOKINETIC, »,/»$
Figun 2. Errors due to anisokiiwtic conditions (taroe particles).
0.2
Figun 3. errors
... Q.S 1A> 1.2 1.4 1-6 ** «
RELATIVE BOKINETIC CONDITIONS, WT, or pwa/pwe
due to anisokinetic conditions (60% small and 50% U»r8a particlw).
M-9
-------
boundaries. It is impossible to exceed the outer boundaries if exact, constant, proportional conditions are maintained.
Realizing this, it can be stated that the true pmr, value lies somewhere between pmr, and pmr6. it may be closer or
even equal to one or the other, depending on the particle size distribution. Without this knowledge, the best that can be
said is:
xv pmr, + pmrc pmr, — pmre
pmr. = - - - ±- - - - (16)
x*s. _
when pmr, is the estimate of the true pmr,.
Under the practical situation, it is impossible to maintain isokinetic or proportional conditions without some degree
of fluctuation. We need to understand how this would affect the sampling results.
Badzioch wrote an equation relating the pollutant mass collected to the actual pollutant mass in the stack as:
v,.
where a = parameter, depending on the inertia of the particle and the gas flow pattern at the sampling nozzle. Also, it was
reported that a was a constant for vn,/vM » 0.5 to 4. Watson [6] approximated the range as 0.5 to 2.
Thus for a given particle size distribution, when c., • constant, then the average (a) is a constant, and:
which is a straight-line function. Further, if 7nt =» vj. or7n, * k 7M. the ratio of mn to m» remains fixed but is biased
depending on the value Vn/v(.
PROPOSED PROCEDURE
FACTS AND ASSUMPTIONS
The bases may now be set for the interpretation procedure.
1. There is no knowledge of particle size distribution or how the pollutant concen-
tration is varying with time.
2. The following data are provided:
a. "v,, mn „ An, Vnt, and 0t. Vnt must be'obtained independently of "v
b. Vne, 08, and",, for each elemental area.
3. Results within ± 10 percent of the true value are desired.
4. There is no deliberate attempt to bias the data.
5. Fluctuation within the stack of both velocity and pollutant concentration at any
point are random..
6. Only averages can be calculated.
PROCEDURE AND EXPLANATION
The following steps should ensure valid results within ± 10 percent of the true value. The limit, ± 10 percent, is purely
arbitrary; an understanding of this example should enable you to set your own desired limits.
With the principles set forth, a method of evaluating source sampling data can now be proposed.
M-10
-------
1. Calculate pmr. and pmre. using independent measurements of Vnt and7..
2. Calculate the ratio pmr./pmre and pmr«~P ± Q.10, reject the results.
pmr. + pmre
• pmr. — pmrc
b. If 0.82 < pmr./pmre < 1.2 or < ± 0.10. go to step 3.
pmr. *• pmrc
3. Calculate—— .1^
Vn. is an integrated volume over the sampling period 0,. whereas V,. is a result of
the readers estimation of the average reading of the inclined manometer. The
inclined manometer of the pitot tube does not give V,. directly but, instead,
yields the velocity pressure (Ap,.). This reading, the Ap,., must be within * 10
percent of the average value [7]. Therefore, if ApM varies more than this amount
during 0., the^rate must be adjusted, and the Ap,. and the time must be recorded
so an average v M can be calculated.
a. If any 1.2 < < 0.82, reject the data.
V..An0.
b. If all 0.82 < < 1.20. average pmr. and prnF0.
V.. An 0.
This value will be within ± 10 percent of the true pmr,.
SUMMARY
There are two approaches used to calculate the pollutant mass rate:
1. The ratio of area method in which the sample collected is weighted according to
the ratio of the cross-sectional areas of the stack and the sample nozzle.
2. The concentration based method in which the sample collected is weighted
according to the ratio of the volumetric flows In the stack and in the sample
nozzle.
The source tester should be aware of how the two methods for calculating the pollutant mass rate can be biased by
the particle size distribution of the pollutant when isokinetic conditions are not maintained. Although it is shown that the
bias is predictable if either all large particles or all small particles are present, the real situation usually lies somewhere
between these predictable limits. A compromise between these two limits then is the best estimate of the true value when
exact knowledge of the particle size distribution is lacking. The procedure recommended is to obtain the average value of
the two methods, which is a model based upon the concept of Hemeon and Haines [2] and others [3, 4, 6] and can be
applied to real sources.
The two methods for calculating pollutant mass rate do not take into account time and cross-sectional variations of
the pollutant mass rate. However the ratio of the methods, pmr./pmrc. can be used to determine the average percent of
isokinetic or proportional conditions. With'additional real time data, e.g., velocity and sample volume reading, a more
detailed evaluation can be made. This shows the necessity of having a velocity measuring instrument during sampling and a
volume meter in the sampling train.
M-ll
-------
REFERENCES
1. W. C. Achinger, R. T. Shigehara. "A guide for selecting methods for different source conditions." J. APCA
1S, 605-609 (September 1968).
2. W. C. L. Hemeon, G, F. Haines, Jr., 'The magnitude of errors in stack dust sampling," Air Repair 4.
159-164 (November 1954). . '
3. S. Badzioch, "Collection of gas-borne dust particles by means of an aspirated sampling nozzle," British J.
of Applied Physics 10. 26-32 (January 1959).
4. S. Bediioch, "Correction for anisokinetic sampling of gas-borne dust particles," J. tnst of fuel, 106-11C
(March 1960).
5. W. D. Snoxvden, R. T. Shigehara, "Non-proportional sampling biases on concentration and pollutant mass
r.-.te." Unpublished paper (1969).
6. H. H. Watson. "Errors due to anisokinetic sampling of aerosols,"/4m. Ind. Hyg, Ass. Quart. 15-16,21-25
* March 1954).
7. R. T. Shigehara. W. F. Todd, and W. S. Smith, "Significance of errors in stack sampling measurements,"
Presented at APCA Annual Meeting, St Louis, Missouri (June 1970).
M-12
-------
SLIDE 153-0 NOTES
ISOKINETC SAMPUNG AND BIAS
FROM NONISOKINETIC SAMPUNG
SLIDE 153-1
ISOKINETIG SAMPLING
1. The velocity entering the nozzle
must be the same as the velocity
in the stack.
2. The particles must be moving
parallel to the stack wall and
directly toward the nozzle.
SLIDE 153-2
EXAMPLE
o — Large particles. These particles
are greater than 100 microns and
are not affected by flow pattern
due to their inertia.
o — Small particles. These particles
are less than 0.3 microns and
move along with the flow pattern
since they have very little inertia.
M-13
-------
SLIDE 153-3
oO
oO
oO
FLOW ^ °o
oO
oO
oO
oO
oO
oO
NOZZLE
00
oO
NOTES
100% ISOKINETIC
vn = vs
mn = 8 grains/min
Q,, = 1 cf m
cn = 8/1 = 8 grains/cf
SLIDE 153-4
FLOW
oQ
0
o
_^000 NOZZLE
-»-ooO
— ooo
— ^-0 o O
O
O
200C
W 7=Z
mn =
Q-
n -
c ~~
200% ISOKINETIC
12 grains/min
2cfm
- 12/2 = 6 grains/cf
SLIDE 153-5
oO
50% ISOKINETIC
vn = 1/2 vs
mn = 6 grains/min
Qn = 0.5 cfm
cn = 6/0.5 = 12 grains/cf
M-15
-------
SLIDE 153-3
FLOW
oO
00
°O
oO
oO
oO
oO
oO
oO
. oO
oo NOZZLE
oO
oO
oO
oO
oQ
NOTES
100% ISOKINETIC
v = v
mn = 8 grains/min
Qn = 1 cf m
cn = 8/1 = 8 grains/cf
SLIDE 153-4
FLOW
200% ISOKINETIC
vn = 2v,
mn = 12 grains/min
Qn = 2 cf m
cn =12/2 = 6 graihs/cf
SLIDE 153-5
oO
oO
50% ISOKINETIC
vn = 1/2 vs
m,, = 6 grains/min
Qn = 0.5 cfm
cn = 6/0.5 = 12 grains/cf
M-16
-------
SLIDE 153-6
RESULTS
NOTES
100%lsokinetic— 8gr/ft3
200% Isokinetic — 6 gr/ft3
50% Isokinetic — 12 gr/ft3
SLIDE 153-7
POLLUTANT MASS RATE EQUATIONS
PMR
I IVIII
..
VsstdAs
mstd
PMR =
Whereas
PMRC — pollutant mass rate calculated on
the concentration basis
mn — mass collected on the filter and
probe
Vm — volume metered by the sample train
"" at standard conditions
v, — velocity of the stack at standard
""' conditions
As — area of the stack
PMR. — pollutant mass rate calculated on
the ratio of areas basis
H — time tested
An — area of the nozzle
M-17
-------
SLIDE 153-3
FLOW
oQ
°o
. °9 .
oO
oO
oO
o O
oO
oo NOZZLE
oO
oO
oO
oO
NOTES
100% ISOKINETIC
vn = vs
mn = 8 grains/min
Qn = 1 cf m
Cn = 8/1 = 8 grains/cf
SLIDE 153-4
FLOW
200% ISOKINETIC
vn = 2vs
mn = 12 grains/min
Qn = 2 cf m
cn = 12/2 = 6 grains/cf
SLIDE 153-5
oO
oo O
oO
50% ISOKINETIC
vn = 1/2 vs
mn = 6 grains/min
Qn = 0.5 cfm
cn = 6/0.5 = 12 grains/cf
M-18
-------
SLIDE 153-8
NOTES
SIMPLIFIED MASS RATE EQUATION
The equations below have aU constant values removed.
M
PMRa = Mr
vSstd,As,e,
and An are all constant
Note: The pollutant mass rate on the concentration basis (PMRJ is a result
of both the mass and sample volume collected. The pollutant mass
rate on the area basis is dependent on only mass.
SLIDE 153-9
RESULTS OF PMR, FOR SMALL PARTICLES
100% Isokinetic - C = ^ = 4 gr/ft3
8
200% Isokinetic - C = = 4 gr/ft3
50% Isokinetic - C = = 4 gr/ft3
M-19
-------
SLIDE
FLOW
153-3
oO
"O
oO
oO
oO
oQ
oO
oO
oO
oO
00 NOZZLE
oO
00
oO
oO
oO
MOTES
100% ISOKINETIC
vn = vs
mn = 8 grains/min
Q0 = 1 cf m
cn = 8/1 = 8 grains/cf
SLIDE 153-4
200% ISOKINETIC
vn = 2vs
mn = 12 grains/min
Qn = 2 cf m
cn = 12/2 = 6 grains/cf
SLIDE 153-5
50% ISOKINETIC
vn = 1/2 vs
mn = 6 grains/min
Qn = 0.5 cfm
cn = 6/0.5 = 12 grains/cf
M-20
-------
SLIDE 153-10
NOTES
PLOT OF % ISOKINETIC
VS.
POLLUTANT CONCENTRATION
i
200%
150%
n TRUE
U VALUE
2
50%
0%
0%
I
50% 100%
% ISOKINETIC
IPMRJ SMAU
150% 200%
SLIDE 153-11
RESULTS OF PMRC FOR LARGE PARTICLES
100% Isokinetic - C = ~ = 4 gr/ft3
200% Isokinetic - C = ~ = 2 gr/ft3
50% Isokinetic - C - — = 8 gr/ft3
M-21
-------
SLIDE 153-3
FLOW _
oO
oO
oO
oO
oO
oO
oO
oO
oO
oO
oo NOZZLE
oO
oO
oO
oO
oO
100% ISOKINETIC
Vn = Vs
mn = 8 grains/min
Qn = 1 cf m
cn = 8/1 = 8 grains/cf
SLIDE 153-4
FLOW
200% ISOKINETIC
Vn =
mn = 12 grains/min
Qn = 2 cf m
cn = 12/2 = 6 grains/cf
SLIDE 153-5
oQ
oO
50% ISOKINETIC
vn = 1/2 vs
mn = 6 grains/min
Qn = 0.5 cfm
cn = 6/0.5 = 12 grains/cf
M-22
-------
SLIDE 153-12 NOTES
PLOT OF % ISOKINETIC
VS.
POLLUTANT CONCENTRATION
IPMH.I SMALL
IPMRJ LARGE
NOTE:
Since no stack contains either all large or all small particles, the bias will be
in the colored area.
SLIDE 153-13
RESULTS OF PMRa FOR SMALL PARTICLES
100% Isokinetic — 4 gr
200% Isokinetic — 8 gr
50% Isokinetic — 2 gr
M-23
-------
SLIDE 153-3
oO
oO
FLOW
OQ
oO
oO
oO
oO
oO
oO
oo
NOZZLE
oO
00
oO
°0
NOTES
100% ISOKINETIC
v = v
mn = 8 grains/min
Qn = 1 cfm
cn = 8/1 = 8 grains/cf
SLIDE 153-4
200% ISOKINETIC
vn = 2vs
mn = 12 grains/min
Q,, = 2 cfm
cn = 12/2 = 6 grains/cf
SLIDE 153-5
oO
50% ISOKINETIC
vn = 1/2 vs
mn = 6 grains/min
Q0 = 0.5 cfm
cn = 6/0.5 = 12 grains/cf
M-24
-------
SLIDE 153-14
PLOT OF % ISOKINETIC
VS.
POLLUTANT CONCENTRATION
NOTES
200%
H 150%
<
oc
t-
1
3 TRUE
8 VALUE
I
0%
0%
50% 100% 150%
% ISOKINETIC
(PMRJ SMALL
SLIDE 153-15
RESULTS OF PMR= FOR LARGE PARTICLES
100% Isokinetic — 4 gr
200% Isokinetic — 4 gr
50% Isokinetic — 4 gr
M-25
-------
SLIDE 153-16
NOTES
PLOT OF % ISOKINETIC
VS.
POLLUTANT CONCENTRATION
\
o
200% —
150% —
UJ
O
Z TRUE
8 VALUE
50%
0%
50%
100%
% ISOKINETtC
150%
(PMRJ SMALL
(PMR.I LARGE
200%
SLIDE 153-17
PLOT OF % ISOKINETIC
VS.
POLLUTANT CONCENTRATION
200%
O
i
a
i-
UJ
u
O
o
s
200%
M-27
-------
SLIDE 153-18 NOTES
The pollutant concentration can be
calculated by either equation; however,
the EPA chose to use PMRC since most
particles for new sources are small and
PMRG gives the true value for small par-
ticles. The proposed regulations had the
tester calculate the results by both
methods and average the results.
SLIDE 153-19
Conclusion
PMR = % Isokinetic pMR
a 100
M-29
-------
SECTION N. PRECISION AND ACCURACY OF TEST METHODS
Subject Page
1. Information to support data quality acceptance for performance
audits and routine monitoring (memo from Dr. T. R. Mauser,
Director, EMSL, EPA, to Dr. Courtney Riordan, Deputy Assistant
Administrator, Monitoring and Support Branch, EPA) N-3
2. Error analyses N-8
3. Slides N-13
N-l
-------
SUBJECT:
FROM:
TO:
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Research Triangle Park, N.C. 27711
DATE: October 10, 1980
Information to Support Data Quality Acceptance Criteria for Performance
Audits and Routine Monitoring
Dr. Thomas R. Mauser, D^__,
Environmental Monitoring Systems Laboratory, RTP (MD-75)
Dr. Courtney Riordan
Deputy Assistant Administrator
for Monitoring and Technical Support (RD-680)
Your memo of September 22, 1980, has generated a large amount of
data gathering and documentation. I have divided it into two sections,
ambient and source. I hope it is some help to you.
Enclosure
cc: D.J. von Lehmden
M.R. Midgett
J.C. Puzak
L.J. Purdue
T.A. Clark
F.J. Burmann
EPA Pom 1320-6 (R.». 3-76)
N-3
-------
STATIONARY SOURCE
Provided here in Table A-3 are the estimates of precision and accuracy
for those source emission test methods that the Source Branch of the Quality
Assurance Division has either collaboratively tested or subjected to a multi-
sample, single-laboratory evaluation. Because of the great expense involved
in the collaborative testing of source emission methods, such tests are not
normally performed unless they are justified by the particular situation.
For example, a method for a pollutant of critical importance, and that will
incur widespread usage, might warrant collaborative testing whereas one that
would be used intermittently for a few industries would not. Where collaborative
testing is not justified and/or budgeting restrictions do not allow the expense,
a multi-sample, single-laboratory evaluation is routinely conducted during the
development and evaluation of the test method to obtain within-laboratory
precision estimates. The estimates in Table A-3 reflect this; there is no
between-laboratory standard deviation shown for those methods that have not
been collaboratively tested.
Because the true pollutant concentration of a stack gas is unknown and
constantly changing, estimates of method accuracy are particularly difficult
to obtain. These estimates are frequently obtained from analysis of standard
cylinder gases, analysis of reference materials that test the accuracy of the
analytical procedure only, or comparison with another Reference method or
instrument to establish relative accuracy.
Table A-4 provides a listing of source emission methods for which precision
and accuracy data are not available.
N-4
-------
TABLE A-3. SOURCE EMISSION METHODS FOR WHICH PRECISION/ACCURACY DATA EXISTS BASED ON COLLABORATIVE TESTS
OR SINGLE-LABORATORY EVALUATIONS
EPA
Method
Standard Deviation
Description/Appl ication
Condition of test Within Lab
Between Lab
Accuracy
Velocity
Volumetric Flow
C0_ (manual)
0« (manual)
MSlecular Weight
Particulate Emission
Stack Moisture Content
6 SOp-Power Plant
Real sample,
Multi- laboratory
3.9% of flow
5.5% of flow
0.2%
0.3%
0.35 g/g mole
10.4% of cone.
0.1%
4.0% of cone.
5.0% of flow
5.6% of flow
0.4%
0.6%
0.048 g/g mole
12.1% of cone.
0.1%
5.8% of cone.
Accurate within limits
of method precision
Not determinable
Within limits of
method precision
Accurate within limits
of method precision
7 NO -Nitric Acid
N0*-Power Plant
8 S0?-Sulfuric Acid Plant
H2S04-Sulfuric Acid Plant
9 Stack Gas Opacity
10 . CO-Refinery FCC
11 H2S-Refinery Fuel Gas
12 Pb
Simulated sample,
Multi-laboratory
Real sample,
Single laboratory
14.9% of cone.
6.6% of cone.
13 ppm
2.1% of cone.
5% of cone.
18.5% of cone.
9.5% of cone.
8.0 mg/m~
2.7 mg/m
2.0% of
opac i ty
11.2 mg/m_
3.0 mg/m
2.0% of
opac i ty
n
n
5%
of
25 ppm
4.5% of cone.
5% opacity at level
of standard
< 24 ppm
4% at level of standard
within limits
of method precision
r—CONTINUED
-------
TABLE A-3. (continued)
EPA
Method Description/Application Condition of test Within Lab
Standard Deviation
Between Lab Accuracy
13A F by SPADNS Analysis
i
o»
13B
15
16
17
23
24
Real sample,
Mu 11 i-1aboratory
F by SIE Analysis
H.S, COS, CS, Sulfur
Recovery
Total Reduced Sulfur - Kraft
Particulate
Chlorinated Hydrocarbons
Volatile Organics from
Paint
Real sample,
Single laboratory
0.044 mg/m .064 mg/m
0.037 mg/m3 0.056 mg/m3
8% of cone.
8% of cone.
6% of cone.
3% of cone.
8% Water Based Paint
0.5% Solvent Based
Paint
101/102 Hg/Chlor-Alkali Plants3
Real samples,
Multi-laboratory
1.6 pg/ml
1.8 ug/ml
-.08 mg/1
-.10 mg/1
10% at level of standard
10% at level of standard
Not determinable
-3%
Not determined
-0.4 ug/ml
104
105
106
110
111
Be
Hg in Sewage Sludge
Vinyl Chloride
Benzene
Hg in Sludge Incinerator
Stacks
H ii
Real samples,
Single laboratory
Real samples,
Multi -laboratory
Real samples,
Single laboratory
Real samples,
Single laboratory
0.4 pg/in
0.2 ug/g
2.5% of cone.
9% of cone.
3
4.8 ug/m
0.6 ug/m -0.13 ug/m
nCCUraLc WICRIR
of method
6.3% of cone. -2% at level of
•t-1 IV at- IAI/A! i
TO. Jj* at. level 1
Unknown
precision
standard
>f standard
a
Precision for analytical portion only.
-------
TABLE A-4. SOURCE EMISSION METHODS fOR WHICH PRECISION AND ACCURACY DATA ARE NOT ..
EPA
Method
Application
Present Status
Comments on Precision/Accuracy
1
4
14
18
19
20
21
25
26
27
28
29
103
107
108
109
Sampling point selection
Estimate of stack moisture
Design of Al Plant-Roof Monitoring System
NH- NO- emissions from fertilizer plants
Calculation of F factor
NO , SO- from gas turbines
A £
Leak test method for valves and pumps
in organic processes
Fugitive emissions estimate by visual
observation
Non-methane organic emissions
Organic emissions from asphalt processing
Reserved
Urea emissions from fertilizer plants
Volatile organic contents of printing ink
Screening method for Be
Vinyl chloride monomer in resin
As emissions from smelters
Visual emissions from coke ovens
Promulgated
Promulgated
Promulgated
Future Proposal
Promulgated
Proposed
Future Proposal
Future Proposal
Proposed
Future Proposal
Proposed
Future Proposal
Promulgated
Promulgated
Future Proposal
Future Proposal
Precision/accuracy not applicable
Expected to be similar to Method 5
moisture determination
Precision/accuracy not applicable
Method under development
Precision/accuracy not applicable
Precision/accuracy not applicable
Method being evaluated
Method under development
Method under development
Precision/accuracy expected to be
similar to Method 104
Method under development
Method under development
-------
ERROR ANALYSIS*
Introduction
The problem of accuracy in stack sampling measurements is considered
and debated in almost every report or journal article in which stack sampling
data appear. There exists, however, a great deal of misunderstanding in the
engineering community on the difference between error, precision, and accuracy.
This misunderstanding often leads to a misinterpretation of analytical studies
of stack sampling methods. The type of error analysis often used applies
only to "randomly distributed error with a normal distribution about the true
value."
A discussion of the definitions of terms normally used in error analysis
will be given in a course lecture. The definitions are also included in this
manual for your future reference. It is hoped that by studying this section
the student will realize the limitations of error analysis procedures and will
be able to more carefully design experiments that will yield results close to
the "true" value.
Definitions
Error: This word is used correctly with two different meanings (and frequently
incorrectly to denote what properly should be called a "discrepancy"):
(1) To denote the difference between measured value and the "true" one.
Except in a few trivial cases (such as the experimental determination
of the ratio of the circumference to the diameter of a circle), the
"true" value is unknown and the magnitude of the error is hypothetical.
Nevertheless, this is a useful concept for the purpose of discussion.
(2) When a number such as a = +_ 0.000008 x 1010 is given or implied, "error"
refers to the estimated uncertainty in an experiment and is expressed
in terms of such quantities as standard deviation, average deviation,
probable error, or precision index.
*
Adapted from Y. Beers, Theory of Errors, Addison-Wesley, Reading, Mass, (1958)
pp. 1-6.
N-8
-------
Discrepancy: This is the difference between two measured values of a quantity,
such as the difference between those obtained by two students, or the difference
between the value found by a student and the one given in a handbook or text-
book. The word "error" is often used incorrectly to refer to such differences.
Many beginning students suffer from the false impression that values found
in handbooks or textbooks are "exact" or "true." All such values are the results
of experiments and contain uncertainties. Furthermore, in experiments such as
the determination of properties of individual samples of matter, handbook values
may actually be less reliable than the student's because the student's samples
may differ in constitution from the materials which were the basis of the hand-
book values.
Random Errors: Sometimes when a given measurement is repeated the resulting
values do not agree exactly. The causes of the disagreement between the
individual values must also be causes of their differing from the "true" value.
Errors resulting from these causes are called random errors. They are also
sometimes called experimental or accidental errors.
Systematic or Constant Errors: If, on the other hand, all of the individual
values are in error by the same amount, the errors are called systematic or
constant errors. For example, all the measurements made with a steel tape that
includes a kink will appear to be too small by an amount equal to the loss in
length resulting from the kink.
In most experiments, both random and systematic errors are present. Some-
times both may arise from the same source.
Determinate and Indeterminate Errors: Errors which may be evaluated by some
logical procedure, either theoretical or experimental, are called determinate,
while others are called indeterminate.
Random errors are determinate because they may be evaluated by application
of a theory that will be developed later. In some cases random or systematic
errors may be evaluated by subsidiary experiments. In other cases it may be
inherently impossible to evaluate systematic errors, and their presence may be
inferred only indirectly by comparison with other measurements of the same
quantity employing radically different methods. Systematic errors may sometimes
be evaluated by calibration of the instruments against standards, and in these
cases whether the errors are determinate or indeterminate depends upon the
availability of the standards.
N-9
-------
Corrections: Determinate systematic errors and some determinate random errors
may be removed by application of suitable corrections. For example, the measure-
ments that were in error due to a kink in a steel tape may be eliminated by com-
paring the tape with a standard and subtracting the difference from all the mea-
sured values. Some of the random error of this tape may be due to expansion and
contraction of the tape with fluctuations of temperature. By noting the tempera-
ture at the time of each measurement and ascertaining the coefficient of linear
expansion of the tape, the individual values may be compensated for this effect.
Precision: If an experiment has small random errors, it is said to have high
precision.
Accuracy: If an experiment has small systematic errors, it is said to have high
accuracy.
Adjustment of Data: This is the process of determining the "best" or what is
generally called the most probable value from the data. If the length of a
table is measured a number of times by the same method, by taking the average of
the measurements we can obtain a value more precise than others, then a weighted
average should be computed. These are examples of adjustment of data for
directly measured quantities. For computer quantities the process may be special-
ized and complicated.
Classification of Errors
Systematic Errors:
(1) Errors of calibration of instruments.
(2) Personal errors. These are errors caused by habits of individual
observers. For example, an observer may always introduce an error
by consistently holding his head too far to the left while reading
a needle and scale having parallax.
(3) Experimental conditions. If an instrument is used under constant
experimental conditions (such as of pressure or temperature) different
from those for which it was calibrated, and if no correction is made,
a systematic error results.
(4) Imperfect technique. The measurement of viscosity by Poiseuille's
Law requires the measurement of the amount of liquid emerging from
an apparatus in a given time. If a small amount of the liquid
splashes out of the vessel which is used to catch it, a systematic
error results.
N-10
-------
Random Errors:
(1) Errors of judgment. Most instruments require an estimate of the frac-
tion of the smallest division, and the observer's estimate may vary from
time to time for a variety of reasons.
(2) Fluctuating conditions (such as temperature, pressure, line voltage).
(3) Small disturbances. Examples of these are mechanical vibrations or,
in electrical instruments, the pickup of spurious signals from nearby
rotating electrical machinery or other apparatus.
(4) Definition. Even is the measuring process were perfect, repeated mea-
surements of the same quantity might still fail to agree because that
quantity might not be precisely defined. For example, the "length" of
a rectangular table is not an exact quantity. For a variety of reasons
the edges are not smooth (at least if viewed under high magnification)
nor are the edges accurately parallel. Thus even with a perfectly
accurate device for measuring length, the value is found to vary depend-
ing upon just where on the cross section the "length" is measured.
Illegitimate Errors: These errors are almost always present, at least to a
small degree, in the very best of experiments and they should be discussed in
a written report. However, there are three types of avoidable errors which have
no place in an experiment, and the trained reader of a report is justified in
assuming that these are not present.
(1) Blunders. These are errors caused by outright mistakes in reading
instruments, adjusting the conditions of the experiment, or performing
calculations. These may be largely eliminated by care and by repetition
of the experiment and calculations.
(2) Errors of computation. The mathematical machinery selected for calcu-
lating the results of an experiment (such as slide rules, logarithm
tables, adding machines) should have errors small enough to be complete-
ly negligible in comparison with the natural errors of the experiment.
Thus if the data are accurate to five significant figures, it is highly
improper to use a slide rule capable of being read to only three figures,
and then to state in the report that "slide rule error" is a source of
error. Such a slide rule should be used for calculating the results
of an experiment having only three or preferably two significant figures.
On the other hand, if the experiment does give five significant figures,
five or six-place logarithm talbes or some other more accurate means of
calculation should be used.
(2) Chaotic Errors. If the effects of disturbances become unreasonably
large - that is, large compared with the natural random errors - they
are called chaotic errors. In such situations are experiment should
be discontinued until the source of the disturbance is removed.
N-ll
-------
SLIDE 154-0 NOTES
PRECISION AND ACCURACY
OF
EPA REFERENCE METHODS
SLIDE 154-1
PRECISION AND ACCURACY
METHODS EVACUATION
• REAL SAMPLE (Multi-Laboratory)
• SIMULATED SAMPLE (Multi-Laboratory)
• REAL SAMPLE (Single Laboratory)
SLIDE 154-2
REAL SAMPLE
(Multi-Laboratory)
Approximately 10 different testing laboratories test
the same source simultaneously. This is usually referred
to as a "collaborative test." This testing is expensive
and testing parameters are not usually varied.
N-13
-------
SLIDE 154-3
SIMULATED SAMPLE
(Multi-Laboratory)
Approximately 10 different testing laboratories test a
common manifold containing a known concentration
of pollutant. This testing is expensive but the pollutant
concentration is known and can be varied.
NOTES
SLIDE 154-4
REAL SAMPLE
(Single Laboratory)
A single laboratory utilizes a "methods evaluation"
train. This train collects a minimum of four samples for
a single point. This testing is less expensive and any
sampling parameters can be varied to determine its
effect.
SLIDE 154-5
N-15
-------
SLIDE 154-6
NOTES
SLIDE 154-7
QUAD TRAIN CONFIGURATION
IMPINGER CONTENTS
METHOD 8 BACK HALF
1 — 50 ml H20
2.— 100 ml 80% IPA
3 — 100 ml 10% H,0,
4 — 100 ml 10% HA
5 — 300 g SIUCA GEL
PHOBE2C1I"-
PROBE1T
PROBE 4 C"
PROBE 3 r~
N-17
-------
SLIDE 154-8
NOTES
EPA
METHOD
2
3
DESCRIPTION
Velocity
Volumetric Flow
CCh (manual)
O2 (manual)
Molecular Weight
STANDARD DEVIATION
Within Lab Between Lab
3.9% 5.0%
5.5% 5.6%
0.2% 0.4%
0.3% 0.6%
0.35 g/g mole 0.48 g/g mole
SLIDE 154-9
EPA
METHOD
5
6
7
DESCRIPTION
Particulate
SO2 - Power Plant
NO, - Power Plant
STANDARD DEVIATION
Within Lab Between Lab
10.4% 12.1%
4.0% 5.8%
6.6% 9.5%
N-19
-------
SECTION 0. SIGNIFICANCE OF ERROR FOR SOURCE TEST OBSERVERS
Subject Paqe
1. Use of significance of error for source test observer's
decisions 0-3
2. Slides 0-11
0-1
-------
USE OF SIGNIFICANCE OF ERROR FOR SOURCE TEST OBSERVER'S DECISIONS
by
Bill DeWees
The addition of numerous test methods, requirements, quality assurance
procedures, allowable options by the tester, alternative methods and published
articles, has made the average agency performance tester and/or observer all
ask the same question. What is really important? If there were an easy an-
swer, the question would not have to be asked. The only easy answer is
the standard military or politician's answer: It varies with the conditions.
Unfortunately, this is the correct answer.
This paper is designed to provide the necessary information and concepts
to allow the agency staff to determine what is important as the conditions
vary.
The tester or observer needs to know three things to determine what is
important.
1) What is the data to be used for, (i.e., proof of compliance, proof
of violation or engineering evaluation)?
2) What are the direction and magnitude of any biases?
3) What is the acceptable bias that will be allowed before rejecting
the results?
Let's look at the three uses of the data and explore what biases would
be acceptable. First, the source is attempting to prove itself in compliance
with the regulation. If the test results conclusively show compliance with the
regulation, any magnitude of bias in the data that increased the measured re-
sults (high bias) could be accepted for proof of compliance. These results may
not, however, be valid for future use in emissions trading or banking. An
acceptable low bias could be any amount that does not change what would be vio-
lation into compliance.
0-3
-------
Since the final results are not known during the on-site testing, the
observer generally would rather have a fixed value to allow or disallow the
test run while on site. Past collaborative tests have shown most of the NSPS
reference methods to have a reproducibility of about + 10 percent. Therefore,
when the source is trying to demonstrate compliance, a good rule of thumb for
allowing biases determined on-site may be less than 10 percent high bias and
5 percent low bias. Setting more stringent criteria than these for each sample
run could be costly in time and money for both the industry and agency.
The second case is when the agency is trying to prove that the source is
in violation with the applicable regulation. Any test data that prove conclu-
sively that the source is in violation could contain any magnitude of low bias.
The low bias will not be challenged by the industry unless the testing does not
comply with the legal requirements as stated by the reference method. When the
agency bears the proof of violation, a good rule of thumb for acceptable bias
would be up to a 5 percent high bias and down to a 10 percent low bias. Again,
let me stress that for proof of violation, meeting the requirements of the
reference method is manadatory.
The final example is data used for engineering evaluation. Any bias may
be acceptable in this case as long as it is quantifiable. The data can then
be adjusted or a confidence limit will be placed on it.
Both on-site and posttest data analysis will be made by the agency. The
agency observer should be aware of his authority and acceptable biases on-site.
It is the belief of the author that an agency observer that is not allowed to
make decisions on-site, does not have the right to observe the test and later
reject data based on his on-site observations. Rejection of a testing series
is both time and cost consuming for the agency and industry. The agency should
not compromise its standards but should make every effort both on-site and in
posttest analysis to obtain test results acceptable for their purpose.
Error from the measurement of most of the sampling parameters have very
little effect on the final data results. Table 1 was designed to provide a
useful tool in estimating the magnitude and direction of biases from measure-
ment errors of most sampling parameters. The parameters are shown separately
but can be added together when more than one parameter has been erroneously
measured. The table was developed using the testing values in the expected
average range of testing. Also, it was assumed that a 2 percent isokinetic
0-4
-------
error makes a 1 percent error in sample concentration. These values, although
not always exact, should be good enough to make the required on-site or post-
test decisions.
To better explain the table, let's use three examples.
EXAMPLE 1
The NSPS test is on an asphalt plant which has a concentration standard
of 0.04 g/scf. It has been discovered that the test team incorrectly measured
the stack temperature. The test team measured value was about 350°F, but the
correct reading should be about 320°F. The question is how much error is there
from a 30°F high measurement? Table 1 shows that for ts, a 10°F error will
cause a -0.4 percent bias for a concentration measurement. Therefore, a +30 F
error would cause a -1.2 percent bias in the concentration measurement. The
30°F error does not meet the requirements of +1.5 percent of the absolute
temperature, however, the error would have little effect on the final data
results and could therefore be allowed. The -1.2 percent bias means that the
value that will be shown in the source test report will be 1.2 percent less
than the value that should have been measured. This bias does aid the source
in trying to show compliance, but the error is so small, it is almost meaning-
less.
EXAMPLE 2
The test is on a dog food fixing tank. The allowable mass emission rate
standard is about 5 Ib/h. The calibration factor of the dry gas meter has
been checked with two critical orifices supplied by EPA. The results of the
check shows the Y factor should be 0.91 but the tester reports a Y factor of
0.97. The error is 0.06, which should be multiplied by the error in the table
for Y at 0.01 which causes a +1 percent. You inform the tester that the data
will likely be biased high by 6 percent. You decide at this point to allow
the tester to proceed as long as he assures you that a good posttest calibra-
tion will be made for the dry gas meter.
At the conclusion of the first run, the posttest leak-check indicated
a leak rate of 0.15 cfm. This is well above the allowable, but the tester
said he will just subtract the leak rate from the final sample volume as
0-5
-------
shown in the reference method. Since the rate of sampling was only about
0.6 cfm, this could potentially cause a 25 percent high bias. You should sug-
gest that the run be invalidated and that another run be made. The tester
informs you he has the right to use the procedures that could cause up to a
25 percent high bias. You should then inform him that you have an obligation
to protect the source as well as the general public and proceed to inform the
facility contact of the consequences that the tester has decided to impose on
the source.
EXAMPLE 3
The test is at a Subpart D power plant. The concentration standard is
0.1 lb/10 Btu. You are familiar with the testing crew and they usually do
a good job. This test happens to be on one of those days when nothing seems
to go right.
You first spot that the pi tot tube and nozzle are not the minimum distance
of 3/4 of an inch apart. This is corrected by simply bending the pitot tube
away from the nozzle. Next, you check the stack thermocouple and both dry
gas meter thermometer readings against each other at ambient temperature. The
stack thermometer reads 81°F; the inlet dry gas thermometer reads 79°F; and
the outlet thermometer reads 63°F. You inform the team of the discrepancy
but they have no way of adjusting the thermometer. You inform them that a
posttest calibration must be performed on both thermometers. To estimate
what error might occur, you use Table 1 to determine the expected error from
the average temperature of the meter (tm), being low by 10°F. The table shows
that 5°F gives an error of -0.9, therefore, a -10°F error would be +1.8 per-
cent error. This means the measured value would 1.8 percent higher than the
true value.
After the second run, the orsat results seem wrong. There must have been
a leak or some procedure was in error. The tester knows that the Op value
should have been about 4.5 percent; however, his results were 7.7 percent 02.
Going back to the table, a 1 percent error at 5 percent 02 will cause a +6.7
percent error, therefore a 3.2 percent error causes a +21.4 percent error.
Since the test team is a reputable one, the tester requests that the test be
invalidated since there was an obvious error. The observer agrees and another
run is performed.
0-6
-------
When the observer receives the final report for review, he notes that the
test team has the static pressure as +6.7 in. H20. The observer thought that
the value should have been -6.7 in. H20; however, he was not sure. To see if
this really makes any difference, he refers to Table 1 and finds that for Ps,
a 2 in. H20 error will cause a +0.1 percent change. His change from +6.7 to
-6.7 in. H20 is -13.2 in. H,,0, which would cause about a -0.6 percent error.
The error is insignificant on the impact of the data, however, the observer
may wish to call the source and determine the actual sign of the static pres-
sure to enhance accuracy of data reporting.
OTHER ERRORS
In addition to the table, four other potential major errors are listed:
1) two leak check procedures, 2) nozzle-pitot tube spacing, and 3) calibration
at the magnehelic.
Generally, the most critical period for noting errors by the observer and
creating errors by the tester is during the sample recovery phase. The ob-
server should be present, if possible, during the sample recovery phase. Both
the probe rinse and used filter should be observed. The filter should have
a clear space all around its border to show that no particulates have been
circumvented. Generally, no particulate should exist that can be easily seen
by the naked eye. No particles of that size should be able to get through
the control device, but if they do, they would not be a health hazard as they
would immediately fall to the ground after existing in the stack. Their pres-
ence usually means that foreign debris has been caught by the sample train.
The color and appearance can also give information on process operation and
failure of the sample box to maintain the proper temperature. A drastic color
change for one of the runs may indicate a process malfunction which should be
checked. Also, as discussed in the paper on the "Role of the Agency Observer",
the apparent mass of particulate collected should be compared to the visible
emissions during test.
CONCLUSION
There are numerous errors and nontypical conditions that can occur during
each sample run. The observer should have a good understanding of the intent
of the test and the magnitude of error that will be tolerated by the agency;
0-7
-------
he should then proceed to make his decision in a logical manner, using all
facts available at the time. When the observer is worried about not meeting
the requirements of the reference method(s), usually a little creative think-
ing on the part of the observer and some posttest work by the test team can
solve the problem. An example would be if the process shuts down with one
point to go in a sample run, test the last point with the process off pro-
vided the fan is still running. If the fan shuts down, you have in fact
sampled the last point at the correct rate (nothing). The posttest rejection
of a test is costly in both time and money to the source and agency. If a
sample run will likely be rejected, reject it on-site since this is far less
costly and time consuming.
0-8
-------
TABLE 1. ERROR ANALYSIS OF SAMPLING PARAMETERS
Parameter
Pbar
AH
tm
Ps
ts
AP
Moisture
Md
Md
Md
Mn
Time
Y
CP
Nozzle
diameter
Isokinetic
F factor
F factor
F factor
True value
30 in. Hg
30 in. Hg
528°R
30 In. Hg
600°R
1 in. H20
10%
29
29
29
100 mg
120 min
1.00
0.84
0.250 in.
100%
5% 02
10% 02
15% 02
Error
1 in. Hg
1 in. H20
5°R
2 in. H20
10°F
0.1 in. H20
1%
1% C02
1% 02
1% CO
1 mg
1 min
0.01
0.01
0.005 in.
10%
1% 02
1% 02
1% 02
Erroneous
value
31 in. Hg
30.07 in. Hg
533°R
30.15 in. Hg
610°R
1.1 in. H20
11%
29.15
29.03
29
101 mg
121 min
1.01
0.85
0.255 in.
110%
6% 02
11% 02
16% 02
Concentration
(%r
+ 4.1
+ 0.2
- 0.9
+ 0.1
- 0.4
- 2.5
+ 0.1
+ 0.1
+ 0.1
_
1.0
- 0.4
1.0
- 0.6
- 2.0
- 5.0,
+ 6.73
+10. n
+20.4°
QS
-1.6
_c
_c
-0.2
+0.8
+4.9
-0.2
-0.3
-0,1
-*
-'•
-Cr
_c
+ 1.2
c
_c
N/A*
N/A*
N/Ae
-------
TABLE 1 (continued)
o Leak Check of the PItot Tube:
A posttest leak check of the pltot tube must be performed at a minimum of 3 1n. H20.
It 1s not possible to posttest calculate the error from a pltot tube that does not
leak check. However, 1f only one side of the pltot tube does not leak check, the test
or observer may wish to determine the maximum error that could have occurred by the
following procedures. Place the pltot tube back Into the stack at a point of average
velocity using the same orientation as 1n the test. Take the Ap reading. Turn the
pltot tube over (180° reortentatlon). Again take the Ap reading. The difference in
the two readings 1s the expected error 1n 1n. H20. If both sides of the pltot tube
leak no error analysis 1s possible.
o Spacing of the Pltot Tube to the Nozzle:
A minimum of a 3/4 1n. spacing 1s required between the pltot tube and nozzle. If the
nozzle-pltot tube spacing 1s only 1/2 1n. an error of a 7 percent high bias 1n the flow
rate may be caused. A lesser spacing can cause even greater high bias error.
o .. -
5 o Calibration of the Magnehellc -vs. the Inclined Manometers;
The error would be the same as reported for Ap.
o Leak Check of the Sample Train:
The train 1s to be posttest leak checked at the maximum vacuum operated during the test.
If the maximum leak exceeds 0.02 cfm, the leak (leak rate times the sample time) is to
be substacted from the sample volume. It 1s suggested when leak check at the nozzle
exceeds the allowable leak rate, the leak check be performed at the nozzle 2 1n. Hg
(or the static pressure, whichever 1s higher). The train should then be leak checked
at the Inlet to the filter. The higher of the two leakage rates can then be subtracted
from the sample volume. Both approaches could cause a high bias for both concentrations
and pmr standards. The percent bias will be somewhere between the maximum (assuming
there was no leakage during the test) and the minimum of zero (assuming the maximum
measured leakage actually occurred during the test).
-------
SLIDE 155-0 NOTES
SOURCE TEST OBSERVER'S USE
OF SIGNIFICANCE OF ERROR
SLIDE 155-1
BASIS FOR OBSERVER'S DECISIONS
1. What is the pupose of test?
2. What is direction and magnitude of bias?
3. What is the acceptable allowed bias?
SLIDE 155-2
USE OF ERROR ANALYSIS TABLE
(From Table 1)
• Errors are calculated using values shown.
• It is assumed that a 2% error in the isokinetic
sample rate results in a 1% error in concentration.
• When more than one error occurs, use the sum of
the errors.
Note: The true value and erroneous measured value are
shown to eliminate confusing the terms "measured
high" and "measured low."
0-11
-------
SLIDE 155-3 NOTES
EXAMPLE 1
For Concentration Standard
1. ERROR Ts: measQred value is 30°F too high.
2. 10°F causes a -0.4% bias (from Table 1).
3. Therefore. +30° F will cause a -1.2% bias.
SLIDE 155-4
EXAMPLE 2
For Mass Emission Standard
PART 1
1. ERROR Y: reported value is 0.06 too high.
2. 0.01 causes a ^1% bias (from Table 1).
3. Therefore, +0.06 will cause a +6% bias.
SLIDE 155-5
PART 2
1. ERROR: leak rate is 0.15 cfm.
2. Sample rate is *» 0.6 cfm.
3. Therefore, if total leak rate is subtracted, bias
could be as high as +25%.
0-13
-------
SLIDE 155-6 NOTES
EXAMPLE 3
For Concentration Standard
PART1
1. ERROR: pilot tube is < % in. from nozzle.
2. Table 1 shows that a Vf> in. spacing causes a
7% bias.
3. Therefore, pitot tube must be bent until
correct spacing is obtained.
SLIDE 155-7
PART 2
1. ERROR: oxygen reading is 3.2% too high.
2. At 5% O2 a 1.0% Oz error causes a +6.7% bias (from
Table 1).
3. Therefore, a +3.2% O* error will cause a +21.4% bias.
SLIDE 155-8
PARTS
1. ERROR: Static pressure reading of +6.7 in.
may have an incorrect sign.
2. A 2.0 HaO error causes a 0.1% bias (from Table 1).
3. Therefore, sign should have been negative not
positive. A -13.4 in. H2O error will cause a -0.6% bias.
0-15
-------
SLIDE 155-9
OTHER ERRORS
• Pitot tube leak-check
• Pitot tube/nozzle spacing
• Magneheiic calibration
• Sample train leak-check
NOTES
SLIDE 155-10
CRITICAL PHASE FOR OBSERVATION
• Check probe rinse for large particles.
• Check filter for large particles and color.
• Check filter for evidence of particle contamination.
< Check ratio of apparent mass collected to visible
emission readings.
SLIDE 155-11
CONCLUSIONS
1. Determine purpose of test.
2. Determine magnitude and direction of biases.
3. Know acceptable bias allowed.
4. Make every effort to meet test requirements
and to use the data.
Note: Test rejection is costly in time and money for both
the source and agency. If sample run will Ijkely be
rejected, reject it on-site.
0-17
-------
SECTION P. STACK SAMPLING NOMOGRAPHS
Subject Page
1. Stack sampling nomographs for field validation (prepared by
Entropy Environmentalists, Inc.) P-3
2. Slides P-27
P-l
-------
INTRODUCTION
This publication is composed of nomographs which Entropy
Environmentalists, Inc. has found to be very helpful in est-
imating or checking parameters measured in stack sampling.
The charts are to be used as guides and should not be con-
sidered as accurate to the third significant figure (even
though some of them are that accurate). The nomographs
are separated into three groups: Moisture Content, Excess
Air, and Volume and Velocities.
Two hints about using nomographs. If you plan to use
the nomographs often, put Scotch "Magic Transparent Tape"
over each line; and when too many marks are made on the
lines, just erase them from the tape. This saves the printed
markings from being erased or obliterated because of ex-
cess use. The other hint is that if you plan to copy any
of these nomographs on a copy machine, be sure that the
machine does not shrink or expand the copy in one direction
more than the other.
P-3
-------
GROUP I - MOISTURE CONTENT
The stack sampler is frequently confronted with the
need to estimate the moisture content of the stack gas
prior to sampling. If he estimates incorrectly, he will
create an isokinetic error of about one percent for every
one percent error in his moisture estimates. For this
reason, a package of moisture nomographs has been assem-
bled which will assist and hopefully improve the sampler's
estimates.
A. Wet.and Dry Bulb Temperatures
Chart 1 is the most useful of the psychrometric
charts for stack samplers, since it not only corrects
for pressure, but it also gives the results in per-
cent moisture (absolute) on a volume basis. Many
stack samplers distrust the wet and dry bulb method
because it has given them erroneous data in the past.
This is often due to lack of pressure corrections,
although the following conditions can also cause
problems:
Acid gases (>10 ppm S03) yield high moisture
results.
Low velocity (<5 ft/sec) yields high moisture
results.
P-4
-------
•a
i
en
25-
26-
27 -
28-
29-
30 -
31 -
32-
33 -
u»
wi
180
-0
-200
Ub
UI
u.
-400 5
-6OO
-800
-1000
-1200
CHAUT 1
AIR - WATER VAPOR PSYCHROMETRIC CHART
(CORRECTS FOR ABSOLUTE PRESSURE CHANGES)
u/ S
y D
Z m
« 3
s S
— 50
h-40
L-30 "5
f
H20 g
u
ui
at
g
r-10
-0
-------
High velocity (>50 ft/sec) yields erratic mois-
ture results.
High temperature (>250°F) yields erratic mois-
ture results. (HINT: Put wet bulb in hot water
instead of cold water.)
Chart 2 is just a simpler chart than Chart 1. It does
not have any pressure corrections and is only good at 29.92
inches of mercury. It is included because it can give you
approximate answers at a glance. Use Chart 3 to correct
for pressure in Chart 2 or any other psychrometric chart.
B. Combustion Calculations
Since most fuels are made of carbon and hydrogen,
it is fairly easy to calculate the moisture content
for combustion sources from the fuel analysis, the
free water in the fuel, the humidity of the combustion
air, and Chart 4. First, you must know the excess
air. Charts 8, 9, and 10, later in this document,
will assist you in this venture.
Next, you need to know the type of fuel. This is
usually known unless a combination of fuels or refuse
is being fired. For a combination of fuels, calculate
from Chart 4-A the answer for each fuel and estimate
some reasonable middle answer. For refuse, since
refuse is usually paper, choose wood.
P-6
-------
-o
I
100 —,
90 —
EXAMPLE:
210
Wet bulb 160°F
Dry bulb 230'F
ANSWER: 30% HO
0 -J
_ 1000
P_ 900
Z_ 800
700
ft.
e
V
600 2
a
0)
500 e
a>
=- 400
=- 300
i_ 200
=- 100
L_ 0
3
03
CHAET 2
Nomograph for calculating percent moisture in stack using
wet and dry bulb thermometers
Assumes 29.92 in. Hg Stack Pressure
-------
EXAMPLES A Psychrometric chart for t. « 200°F
a
and t « 130*F, yields 11% moisture;
however, the absolute stack pressure
is 25 inches Hg.
True Moisture - 1.4 x 11%
15.5% moisture
CHART 3
CORRECTION FACTOR PRESSURE CORRECTIONS
FOR THE PSYCHROMETRIC CHARTS
P-8
-------
*- 50
o
g 5
^ §
S-«
x
*-«
<
VI
M
U
X
u
— 200
- 300
400
50C
600
700
800
900
1000
2:
15
- 10
_ 1
_ 0.5
Wood
Bark
- Propan*
Gasoline
12 Fuel Oil
. Bunker "C" Oil
Bituminous Coal
Subbituminous and
Lignite
- Anthracite
1500
Figure A
FOR DETERMINING MOISTURE III FLOE GAS
FROM COMBUSTION OF FUEL
— 100
• 200
•300
400
500
600
700
800
900
1000
* .4 ~
81 -
.5.8
-Coke
~—
L.
-
_ m
•
— '
~
—
™
r
-
1UU
50
40
30
20
10
^
2
1
0.5
ii
£
s
&
*
J
xv
>l
;
— iu
— 90
„
— 80
1. 70
— 60
_ 50
1 40
- 30
- 20
— 10
Figure B
FOR DETERMINING MOISTURE IN FLUE OAC
FROM FREE HATER IN FUEL
10 —I
e __
o
X
»
0 —
— 0
— 50
x
Id
H
U
rt
100
KJST mo* t) y^ of
2) Free H«tex in Fuel
3) Hunidity of Aablent Air
EXAMPLE) Lignite with 40% free w»ter it
burned at 50% ExceM Air, which !• 90 *F
at 40% Relative Humidity. Add 2.5%
(from fuel - Figure A), 6% (fro* fr««
water - Figure B), and 2% (froa ambient
air - Figure C) to get 10.5% moisture
in the stack gases.
CHART 4
NOMOGRAPHS FOR ESTIMATING MOISTURE IN COMBUSTION SOURCES
Figure C
MOISTURE FROM THE AMBIENT AIR
-------
The free moisture in the fuel is not readily
apparent to the casual observer. Coal and anthra-
cite usually contain from three to fifteen percent,
lignite and bark, ten to forty percent, and wood
and refuse, five to fifty percent. If it is rain-
ing on the fuel, pick a higher number. The source
may have some measured data you can use.
The ambient air moisture is usually known. The
local radio station usually gives it as percent
relative humidity, so Chart 4-C corrects that to
percent moisture (absolute).
C. Condenser and Silica Gel Methods
If all estimating methods fail, try measuring
the moisture directly. Chart 5 is for low volumes
which is associated with silica gel tube methods.
Chart 6 is for larger volumes, using the EPA Method
4.
P-10
-------
Ref. 1
P , inch H3
2C —
25 —
A_ - - ~"
•5
T3
I
EXAMPLE: F " 30 in. Hg
ID
T « 100»P
VL - 1 ml HjC
V - 1 ft-
D
Draw line fron P to T to obtain Point 1
D •
Draw line froB Poir.t A to V, and read B on Ref. 2.
Draw line fron Poir.t B to V^ and obtain answer of
4.9% H.O in Etack cas.
Rel
T , T
m
150
-
J-S0---:
-
.
53
0
-50
Ref. 1.
ifif. 2.
ler of
'. 2
Answer
*H20
50 -
40 -
30 -
20 -:
•
10 -i
.
Be
, 5- —
"~ ---____ 4 -
2 -
1 -
- 10
: s v nl H2° v,
- 7
- 6
- 5
— 4
*- 3
— 2
lf^
- 1.0
- 0.8
- 0.7
- 0.6
- 0.5
- 0.4
- 0.3
- 0.2
•
- 0.1
.' ft3
- 0.2
-
- 0.3
i- 0.4
- 0.5
>- 0.6
_ 0.7
— 0.8
_ 0.9
- 1.0
.
- 2
— 3
— 4
- 5
- 6
- 7
- 8
- 9
- 10
CHART 5
NOMOGRAPH FOR CALCULATING MOISTURE CONTENT FROM LOW VOLUMES
-------
tJ
I
V., ml H-0
1000 * 2
REF. 1 REF. 2
P , inch Hg
m
20-,
.
25-
•
30-
35-
_ , — """
— -*•
V °F
150 —
—
10.0 r-
— **
A_ _--'""" -
* ~- - -. _ __ 50 ~
-
o—I
-
m
-50 —I
EXAMPLE: P - 30 in. Hg
m
Answer
% HLO
2
50-
40-
30 -
20-.
•
10 ^
.
B - -
... 5—
"*""--- 4 -
2 -
1 -
— .
T - 100°F
m
V « 100 ml HO
V - 100 ft3
m
Draw line from P to T to obtain Point A on Ref. 1.
mm
iraw line from Point A to V. and read B on Ref. 2.
1
* 1»KK__B* __»»«! .. ft
- 900
- 800
-700 x/
- 600
- 500
- 400
- 300
- 200
. JOO
_ 90
80
- 70
- 60
- 50
- 40
— 30
•* W
20
- 20 'm'
*
- 30
- 40
- 50
- 60
- 70
- 80
- 90
- 100
- 200
V
- 300
_ 400
- 500
- 600
- 700
- 800
- 900
L 1000
- 10
4.9% H20 in stack gas.
CHART 6
NOMOGRAPH FOR CALCULATING MOISTURE CONTENT FROM HIGH VOLUMES
-------
GROUP II - EXCESS AIR
Knowledge about excess air in a combustion source
is necessary not only for use in nomographs such as
Chart 4, but it is also helpful for interfacing between
stack samplers and combustion experts.
A. Excess Air Versus Flue Gas Composition
Let's say a source is burning a waste oil which
is like pentane. If a line is drawn from pentane
to 240 percent excess air on Chart 7, the nomograph
says the flue gas should have about 15.0 percent
O2 and 4.2 percent COg. Conversely, if a line is
drawn from pentane to 15.0 percent O2, it says that
there should be 4.2 percent CO2 and 240 percent excess
air. This Chart is useful for calculating excess air,
or for validating orsat data, or for calculating CO2
from 02 data.
B. Low Excess Air Versus Composition
Chart 8 is the same as Chart 7, except it is for
lower excess air and has a dry molecular weight line
on it. Some may recognize this as being similar to
a chart published in "Atmospheric Emissions from
P-13
-------
1500-1
20
01
CO
I
H
400-
300-
200-
100-
50-
19
18
17
— 3
•10
Example: Known: 240% excess air burning Pentane
Answer: 15% O & 4% CO in flue gas
4 _ _
S
Q
m^m f
6 CM
8
8 *
10
15
20
Refuse, Bark
and Wood
— Methane
Average Natural Gas
Ethane
Propane
Pentane
Gasoline
#2 Fuel Oil
Bunker "C" Oil
(#6 Fuel Oil)
- Bituminous Coal
" T-Sub-bituminous & Lignite;
- Anthracite
Coke
CHART 7
NOMOGRAPH FOR ESTIMATING FLUE GAS COMPOSITION,
EXCESS AIR OR TYPE OF FUEL
P-14
-------
-o
i
171
Example: Known: 50% Excess Air
burning No. 6 oil
Answer: 7.2% 0 , 10.8% CO
and a dry molecular weight of 30
4 METHANE
AVERAGE
NATURAL GAS'
ETHANE -
PROPANE
BUTANE
PENTANE ~
L GASOLINE
- KEROSENE
NO. 2 FUEL OIL
- NO. 4 FUEL OIL
- NO. 5 FUEL OIL
NO. 6 FUEL OIL
•BUNKER "C" OIL
HIGH
VOLATILE
BITUMINOUS
LOW VOLATILE .
BITUMINOUS
SEXIANTHRACITE
ANTHRACITE
COKE
MEDIUM VOLATILE
BITUMINOUS
•BARK & WOOD
CHART 8
NOMOGRAPH FOR ESTIMATING MOLECULAR WEIGHT OF DRY FLUE GAS
-------
Coal Combustion - An Inventory Guide", by W. S. Smith
«-
and C. W. Gruber, P.U.S. No. 999-AP-24. Since then
the chart has been improved and the information in-
creased.
C. Molecular Weight Versus Excess Air
Chart 9 gives dry molecular weights for different
fuels and amounts of excess air. Chart 10 can be
used to convert dry molecular weights to wet molecular
weights.
P-16
-------
EXAMPLE: Lignite is burned at
50% excess air
Answer: the dry molecular
weight is 30.25
ai
H
1500 -,
1000 -
800
700
600
500
400 -
U)
S 300
200 -
100 -
50 -
0 -I
- 29.0
- 29.5
.- 30.0
- 30.5
31.
31.5
Bark,
Wood &
Refuse
_ Methane
Average Natural Gas
Ethane
Propane
Pentane
Gasoline
#2 Fuel
- Bunker "C Oil
4^ (#6 Fuel Oil)
• Bituminous Coal
"P-Subbituminous & Lignite
Anthracite
- coke
CHART 9
NOMOGRAPH FOR ESTIMATING DRY MOLECULAR WEIGHT FROM
EXCESS AIR AND TYPE OF FUEL
P-17
-------
EXAMPLE: a dry molecular weight of
30.25 in 10% moisture gas
stream gives a 29 wet
molecular weight
32 -i
30 -
28 -
26 -
24 ~
22 -
20 -
IB
— 28
Air
29
— 30
— 31
CHART 10
NOMOGRAPH FOR ESTIMATING WET MOLECULAR
HEIGHT FROM DRY MOLECULAR WEIGHT AND MOISTURE
P-18
-------
GROUP III - VOLUME AND VELOCITY
Sizing nozzles, estimating Flow rates, and just chock-
ing data requires a decent handle on stack velocity or total
volumetric flow.
A. Characteristics of Coal-Fired Equipment
Chart 11 is a very handy chart which was included
in "Atmospheric Emissions from Coal Combustion - An
Inventory Guide". The volumes appear to be correct
except those for stokers with control equipment,
which reflect the volume at maximum capacity. As
an example, we have a 100,000 pounds of steam per
hour spreader stoker fitted with draft-controlled
(constant volume) multiple cyclones. The chart
would tell us that the boiler input was about 120
million Btu per hour, burning about 8000 pounds of
coal per hour, it could generate about 10 megawatts,
the stack gas was about 28,000 scfm at 35 percent
excess air, coal to steam efficiencies in the lower
80 percent, stack gas temperatures about 500*F, and
could be used in a hospital or even as a large in-
dustrial boiler. The important thing to note is
that if this boiler is running at half load, the
P-19
-------
ro
o
CLASSFICATION
OF
BUILDING AND
PLANT
SIZE RANGES
1
| CHOW!- Si»ll IH8STIIU IITI ftOC
.
fcM»
1 1
1
ctowm-Niiic uniin STEM IIECIIIC CEIEUIIOI snuoi
B-uitf htUtllin llti Nicest SIf»i |
, Jawfni-cHTiii tun*
U -UM lUTitiimuL.mw
^^^^^^^Bi 1", '.". ifil1; !'r,Taf?tffffSter^^M
ICmmt-ICMOLS. CMICMES. tULL CHLECIi. ««c 1
6W U- 1 to 4 ASytilu«?TT nm* '
FIRING METHODS
RANGE OF
EQUIPMENT
SIZES
EFFLUENT
riLS.tte. 1
H rMIUEMEt CML FIIEO UllfJ 4 CfCLOIC full
1 Mill 91 TIMELIIC CUIf 1
1 MTCI COOLEO VIIU (1C SMTE 1
l,spif-sni
ilCI AUTMUTIC MCliCfAMl
SlltLE IETOII UIDEIFEEI SIOIEI
CUSSI (CUSSlI CltSSI 1 CLUI4 1
MII FIIEO iHirmr 1
LT 1
-. , i,
1 MO ISO TOO ISO |5o
COAL TO STEAM
EXCESS AIR,%
STACK GAS EFFLUET
clina16O*Ftlatni
at indicated
EMM Air
EQUIVALENT
UNIT CAPACITY
IM MEGAWATTS
91 I0.50O BTU/KW
BOILER OUTPUT 1
I.OOO Ib STEAM '
ptr HOUR at !
IDOOBTU /*> STEAM
BOILER INPUT
T 1 1 — '
JJ W U
T — n — n — i —
IN- M 15 H fl n 1
1 1 I—J—
ro i
•
1 1 1 1 ^~
i H » M r«
1 1 III! 1 1 1 1 1 III! 1 1
90 100 500 WOO
f
1 t
jl
1
III! 1 1 1 II Mil 1 till Illl
01 05 I 10 5 ' It
1 1
1 1
Ib. COAL ptr HOUR 1 I I I I Mllll | 1 1 I I I III
TOILER INPUT I
10 so 100 500 um
1 1
MILLION BTU ! | 1 1 1 M III 1 1 1 1 1 1 III
ptr HOUH 0, I}' 1.0 J 10
»«.-- TUmiK CUTE 1
i*un 01 OWFW curt
-,„ wr-wur«
CUSS5
1 i
SM
1
5Ti
' i i i
1 ' '
SOO 450 400
1 '
i-] i
j ,
» >
MM II
1 1 .
5- M
1 M 1 1 III
UK IUOO j ' 5400C KKJJXXI
I
.
SM
1 1
1
1 — _J
- 1 1
a i
IKS
-
900
1 :
I
0
1
1
1 1 1 1 1 III 1 1 1 Illl
30CJXC JOO>: iJW.MO KLOOO.OOO
1 1 1 1 1 llfl 1 1 1 1 1 Illl 1 1 1 M 1 III 1 1 1 M II
5 U X 100 500 iM SjOOO
(!
II 1 1 1 1 Mill 1 1 1 1 1 Illl 1 1 1 1 1 II
„
1 III
5JOO
m MO !u»o uoc tooo 50000
II Illl ll'lll 1 Mil Till 1 Mill
(MOO UiOOft IOILOOO WOJOO LOOO.OOO &400.000
1 t
1 1
1 1 1 Mill ,1 1 1 1 1 MII 1 Illl Illl 1 1 1 1 Ml
50 100 500 IjOOO SJOO ftjOOO SOMO
SPR'- SPREADER STOKER • •• «"»» • o«u«t«
CHART 11
•«LIt» I (KITH
SUMMARY OF CHARACTERISTICS OF COAL-FIRING EQUIPMENT
-------
volume will be about the same, the excess air about
270 percent, and a gas temperature of about 200°F.
This sort of thing does not happen with pulverized
boilers with electrostatic precipitators.
B. Volume Versus Heat Input
Chart 12 is a more exacting chart which can cal-
culate the flow rate up a stack on a combustion sourco
if the heat input is known. The data for this chart
is in an unpublished paper as of April 1973, called
"A Method of Calculating Power Plant Emission Rates",
by R. T. Shigehara, R. M. Neulicht, and W. S. Smith.
As can be seen from the chart, the heat input need
not be measured if the volumetric flow rate and ex-
cess air is known.
C. Pitot Velocity Readings
The novice often finds it difficult to relate
pitot tube readings into actual velocities. By
using Chart 13, one can quickly relate an "S" type
pitot tube reading into a velocity which is usually
near the actual value. This chart also has a scale
so one can correct the velocity to standard (STP)
conditions which are 68°F and 29.92 inches of mer-
cury pressure.
P-21
-------
Oil -
—
Iw
-o
f\3
Anthracite -
REF
- Gas 100-1
90-4
j
80-j
1
70-]
^""^-^ H 60|
w "SO-H-
W |
x 1
W 40 H
<*> I
30-4
- Bituminous 20 ~"1
— _
and Lignite 11
1
10 -\\
0 -1
r- 200
- 190
- 180 o
m
-170 Q
<
w
>- 160 D
O
-150 z
W
-1^0— ^
w
>- 130 u
fe
- 120 H
DQ
lllO S
- 100
.
- 90
Bituminous
and Lignite
Gas
i- Anthracite
- Oil
EXAMPLE: 1 million BTU/hour of oil
is burned at 50% Excess Air.
How much gas volume is produced?
ANSWER: 14,200 cf/hr. 9 70°F dry
CHART 12
VOLUME VERSUS HEAT INPUT CHART
-------
EXAMPLE: Stack temperature 500°F
AP = 0.5 inches HO
Answer: Actual approximate Velocity = 54 ft/sec
Approximate velocity at STP* = 30 ft/sec
100 -t-6000
fa
o
> 2000
•o
«1000
o
u 500
o
o
I 0
to
H
|
(0
_o
90 -
80 -
70 -
U 60 —
W
-5000
— 1000 O
-1500 3
o
*H
t-2000 fa
-4000
IL-
bT 50 H-3000
40 -
30
20 -
.° 0
_2000
-1000
CHART 13
Approximate velocity Nomograph
Assumes Type "S" pitot tube used at 1 ATM in Air
STP » 68°F & 29.92 inches of mercury
z
H
1
U
8
P-23
-------
Chart 11 corrects for the errors in Chart. 13, not
only for the actual velocity but also Tor velocity
that has been corrected to STP. The example given
is a very extreme case which could exist after a
venturi scrubber, but before a fan (high moisture
gives low molecular weights). This extreme example
was given in order that you not implicitly trust
Chart 13, especially under extreme conditions.
P-24
-------
H
CO
fa M
05 0
^ P
rt!
64 w
l&
|o
O
u
1.0-
-
0.9—
-
0.8—
0.7—
o.e-
0.5—
^v
M
w
10-,
15 -
- -20—
25 —
30 —
35 -
W
X
u
2
QU
to
O
WJ
s
— 0.9
IX
o
— 1.0 os H
(M W
z
— 1.5
i- 2.0
^ 2.5
u
o
u
EXAMPLE: From Chart 13
Approx. Actual Velocity 54 ft./sec.
Approx. STP Velocity 30 ft./sec.
Actual Molecular Weight (MW> = 25
Actual Stack Pressure = 20 inches Hg
ANSWER: Actual Velocity 1.32 x 54 = 71 ft./sec.
STP Velocity 0.87 x 30 = 26 ft./sec.
CHART 14
CORRECTION FACTORS FOR VELOCITY CHART
P-25
-------
IN
ounce
/JL.AMPLINO
MO -
120
100
80 -
60
CT)
40 ~
0 -
uu
O
f
Ul
13
a
a
5
uu
l~
oe
Ul
H-
Ul
s
TIME ONE CUBIC FOOT WITH 1
ORIFICE MGTSR AH = 2.00 |
en
X
.c
U4
§ ,
W I
Ul t
Of /
°- /
/.
- r
Ite /
ut r~
3
O 1
o- f—
< /
1
35
20
O
CL
- 2.4
- 2.2
2.0 O
p<
I
©
1.8 X
O
- 1.6
- 1.4
- 1.2
01
5
ce
O
- 1.0
Date:
Me toi1 Box
CAI.IRRATION CMIXK - I-PA TRAIN METER BOX
Given A H,:
A
Graph A Il,:
-------
SLIDE 156-0
NOTES
STACK SAMPLING NOMOGRAPHS
FOR FIELD USE
SLIDE 156-1
100 —,
90 _:
80 _:
Example: Wet Bulb - 160°F
Dry Bulb - 230°F
Answer: 30% H2O
0 -3
_ 1000
_ 900
chart 2
P-27
-------
SLIDE 156-2
NOTES
r. i
P , Inch Bg
20-,
V , ft5
Example: R. = 30 in. Hg
Tm = 100°F
v. = 100 ml H2O
Vm = 100 ft3
4.9% H2O
4OO
500
600
700
BOO
900
1000
Answer
1O
chart 6
P-29
-------
SLIDE 156-3
NOTES
Example: Known: 50% Excess Air
Burning No. 6 Oil
Answer 7.2% O>, 10.8% Ca2
I
ai w*«zijjui wi ou
/ '?9-4 METHANE -
6-;j / AVERAGE
3 1 NATURAL GAS"
y / ETHANE -
'V / '9 c PROPANE -
i
-3 J BUTANE -
« J' / 2 PENTANE -
J / 5
' -j I !
, / / £
loj] A G
i / g
r3ss++*fcf "£"'""""
1 L -° *
^ / /
/ ^ HIGH
/A VOLATILE
BITUMINOUS
LOW VOLATILE .
.., BITUMINOUS
r " SEhtlANTHRACITE
A
t
ANTHRACITE
*i.O COKE
- GASOLINE
- NO. 2 FUEL OIL
- NO. 4 FUEL OIL
- NO. 5 FUEL OIL
•- BO. 6 FUEL OIL
I- BUNKER "C" OIL
]
MEDIUM VOLATILE
> BITUMINOUS
• BARK £ WOOD
•
a
H«
8,
a
M
8
charts
P-31
------- |