&EPA
United States
Environmental Protection
Agency
Air Pollution Training Institute
MD 20
Environmental Research Center
Research Triangle Park NC 2771 1
EPA 450/2-79-006
December 1979
Air
APTI
Course 450
Source Sampling
for Particulate
Pollutants
Student Manual
-------
United States
Environmental Protection
Agency
Air Pollution Training Institute
MD20
Environmental Research Center
Research Triangle Park NC 27711
EPA 450/2-79-006
December 1979
Air
APTI
Course 450
Source Sampling
for Particulate
Pollutants
Student Manual
By
G.J. Aldina
and
J.A. Jahnke, Ph.D.
Northrop Services, Inc.
P.O. Box 12313
Research Triangle Park, NC 27709
Under Contract No.
68-02-2374
EPA Project Officer
R. E. Townsend
United States Environmental Protection Agency
Office of Air, Noise, and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, NC 27711
^^^1 w
QDU
-------
Notice
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 represent the present state of
the art as well as subject areas still under evaluation. Any mention of products or
organizations does not constitute endorsement by the United States Environmental
Protection Agency.
Availability of Copies of This Document
This document is issued by the Manpower and Technical Information Branch, Con-
trol Programs Development Division, Office of Air Quality Planning and Standards,
USEPA. It is for use in training courses presented by the EPA Air Pollution Training
Institute and others receiving contractual or grant support from the Institute.
Schools or governmental air pollution control agencies establishing training programs
may receive single copies of this document, free of charge, from the Air Pollution
Training Institute, USEPA, MD-20, Research Triangle Park, NC 27711. Others may
obtain copies, for a fee, from the National Technical Information Service, 5825 Port
Royal Road, Springfield, VA 22161.
-------
I AIR POLLUTION TRAINING INSTITUTE |
? MANPOWER AND TECHNICAL INFORMATION BRANCH
CONTROL PROGRAMS DEVELOPMENT DIVISION
OFFICE OF AIR QUALITY PLANNING AND STANDARDS
The Air Pollution Training Institute (1) conducts training for personnel working on the develop-
ment and improvement of state, and local governmental, and EPA air pollution control programs,
as well as for personnel in industry and academic institutions; (2) provides consultation and other
training assistance to governmental agencies, educational institutions, industrial organizations, and
others engaged in air pollution training activities; and (3) promotes the development and improve-
ment of air pollution training programs in educational institutions and state, regional, and local
governmental air pollution control agencies. Much of the program is now conducted by an on-site
contractor, Northrop Services, Inc.
One of the principal mechanisms utilized to meet the Institute's goals is the intensive short term
technical training course. A full-time professional staff is responsible for the design, development,
and presentation of these courses. In addition the services of scientists, engineers, and specialists
from other EPA programs governmental agencies, industries, and universities are used to augment
and reinforce the Institute staff in the development and presentation of technical material.
Individual course objectives and desired learning outcomes are delineated to meet specific program
needs through training. Subject matter areas covered include air pollution source studies, atmos-
pheric dispersion, and air quality management. These courses are presented in the Institute's resi-
dent classrooms and laboratories and at various field locations.
R. Alan Schueler I/James A. Jahn&e
Program Manager Technical Director
Northrop Services, Inc. Northrop Services, Inc.
Jean jf Achueneman
Chief, Manpower fif Technical
Information Branch
-------
Preface
This manual is to be used in conjunction with the lectures and laboratory
presented in Course 450 of the Air Pollution Training Institute. A student
workbook accompanies these materials.
Portions of this manual may become obsolete as regulations and methods
change. Since the field of air pollution measurement progresses rapidly, efforts
should be made by the student to keep abreast of new developments by attending
EPA workshops and supplementing the material in this manual with information
from the current literature.
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TABLE OF CONTENTS
Preface v
Introduction to Source Sampling **
Chapter 1: Basic Definitions
Source Sampling for Paniculate Emissions 1-1
Isokinetic Source Sampling 1-1
Moisture Content of a Stack Gas 1-1
Mole Fraction of a Gas 1-1
Molecular Weight of a Stack Gas 1-1
Ideal Gas Law 1-2
Absolute Temperature 1-2
Absolute Pressure 1-2
Pitot Tube 1-3
Dry Gas Meter Correction Factor 1-4
Orifice Meter 1-4
Nomograph 1-5
Chapter 2: Basic Concepts of Gases
Expression of Gas Temperature 2-1
Expression of Gas Pressure 2-1
The Law of Ideal Gases 2-3
Calculation of Apparent Molecular Weight
of Gas Mixtures 2-5
Gas Density 2-5
Viscosity 2-5
Specific Heat 2-7
Reynold's Number 2-8
The Equation of Continuity 2-9
Bernoulli's Equation 2-10
Chapter 3: The EPA Method 5 Sampling Train
Source Sampling Nozzle 3-3
The Pitot Tube 3-4
Sampling Probe—Pitot Tube Assembly 3-5
The Sampling Case 3-6
Traverse Support System 3-7
Sample Case Glassware 3-7
The Umbilical Cord 3-7
The Meter Console 3-7
The Nomograph 3-8
Alternative Methods and Equipment 3-8
Chapter 4: Calibration Procedures
Calibration of the Source Sampling Meter Console 4-1
Calibration of Temperature Measurement Devices 4-5
Calibration of the Type S (Stausscheibe) Pitot Tube 4-8
Barometer Calibration 4-15
Calibration of a Standardized Dry Gas Meter 4-15
Calibration of a Source Sampling Nomograph 4-17
Calibration of the Probe Nozzle Diameter 4-21
ini
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Chapter 5: The Source Test
Methods for Setting the Isokinetic Flow Rate 5-3
Sampling Meter Console Operation 5-7
Sample Case Preparation 5-9
Sampling Probe Preparation 5-10
Cleaning and Analytical Procedures for the
Method 5 Sampling Train 5-12
Safety on Site 5-15
Method 5 — Source Test Data Sheets 5-19
Chapter 6: Source Sampling Calculations
Equipment Calibration Equations 6-1
Source Sampling Calculations 6-3
Chapter?: Report Writing
Presentation 7-1
Introduction 7-1
Summary of Results 7-1
Process Description 7-2
Testing Methodology 7-2
Results 7-2
Appendix 7-2
Quick Reference Outline for Report Writing 7-3
Chapter 8: Error Analysis
Error Analysis 8-1
Role of the Observer 8-4
Chapter 9: Additional Topics
Sampling Train Configurations 9-1
Reporting in Units of the Standard: F Factor Methods 9-5
Particle Sizing 9-16
Opacity Monitoring 9-23
Appendixes
A. Bibliography A-l
B. Suggested References B-l
C. Derivation of Equations C-l
Pilot Tube Equation C-l
Isokinetic Rate Equation C-4
Isokinetic Variation Equations C-6
Concentric Equal Areas C-8
Equivalent Diameter Equation C-ll
Equations for Measuring Water Vapor C-12
Relative Humidity C-l6
Proportion of Water Vapor C-20
Equation for Molecular Weight of a Stack Gas C-22
D. Concentration Correction Equations D-l
E. International Metric System E-l
F. Conversion Tables F-l
G. Constants and Useful Information G-l
Constants G-l
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Introduction to Source Sampling
The Clean Air Act was enacted to protect the quality of the nation's air
resources. It initiated research and development programs to monitor and control
pollutants emitted to the atmosphere. Emissions from stationary sources are
monitored under the statutes of the act.
Stationary source sampling is the experimental process for evaluating the
characteristics of industrial waste gas stream emissions into the atmosphere.
Materials emitted to the air from these sources can be solid, liquid, or gas; organic
or inorganic. The effluent pollutants emitted to the atmosphere from a source may
contain many different pollutant materials. The quantity and type of each pollu-
tant must be known so a control strategy can be formed. The procedures outlined
in the Code of Federal Regulations, Methods 1-5 for isokinetic stationary source
sampling are a versatile system for evaluating these emissions.
The isokinetic source sampling procedures written in the Code of Federal
Regulations give the environmental and industrial engineer a great deal of data on
the operation of an individual process. The sampling system measures a number of
variables at the source while extracting from the gas stream a sample of known
volume. The information on source parameters in conjunction with quantitative
and qualitative laboratory analysis of the extracted sample makes possible calcula-
tion of the total amount of pollutant material entering the atmosphere. These data
are important for controlling pollutant emissions, evaluating source compliance
with regulations or providing information upon which control regulations will be
based. The industry performing source sampling gains information on the opera-
tion of the process tested. The sampling of source emissions gives valuable process
data which can be used to evaluate process economics and operation control. Infor-
mation gathered during a source test experiment may also be used for determining
existing control device efficiency or for designing new process and emissions control
equipment.
Isokinetic source sampling provides a great deal of important data on the
operating parameters and emissions of an industrial stationary source. This infor-
mation is used as the basis for decisions on a variety of issues. The data taken dur-
ing a source test experiment must, therefore, be a precise representation of the
source emissions. This task requires a thorough knowledge of the recommended
sampling procedures in conjunction with an understanding of process operations.
The typical industrial process may vary conditions at the source for a variety of
economic or logistical reasons. The source sampling experiment must be designed
to prevent process variation from biasing the source sample. The test engineer has
the additional problems of carrying out an important experiment under extremely
difficult working conditions. These problems make source testing an endeavor that
should be performed only by trained personnel.
IX
-------
The Air Pollution Training Institute has assembled the materials contained in
this manual to assist the engineer and technician involved in performing source test
experiments. The manual presents the theoretical evolution of the isokinetic
methods and practical step-by-step descriptions of the application of these methods.
The equipment used is diagrammed and operations are thoroughly explained.
The Air Pollution Training Institute Course 450 laboratory, lectures, and
classroom workbook —in conjunction with the materials contained in this
manual —represent a comprehensive training experience in source sampling with
EPA Method 5 procedures.
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Chapter 1
Basic Definitions
SOURCE SAMPLING FOR PARTICULATE EMISSIONS:
Source Sampling methods are used to determine emission compliance with
regulatory statutes. Source testing provides data on the pollutant emission rate.
Test data are also used to evaluate best available control technology.
ISOKINETIC SOURCE SAMPLING
Webster's dictionary defines iso as denoting equality, similarity, uniformity. Kinetic
is defined as of, pertaining to, or due to motion. Isokinetic sampling is an equal or
uniform sampling of particles and gases in motion within the stack.
Isokinetic source sampling is achieved when the velocity of gas entering the
sampling nozzle is exactly equal to the velocity of the approaching gas stream. This
provides a uniform, unbiased sample of the pollutants being emitted by the source.
Isokinetic source sampling most closely evaluates and defines various parameters in
the stack as they actually exist at the time of sampling.
MOISTURE CONTENT OF A STACK GAS
The moisture content of a stack gas is the percentage of water vapor present
calculated on a volume basis. The moisture content of the stack is important in
calculating the apparent molecular weight of the stack gas, which must be known
for application of the ideal gas law. The ideal gas law defines the relationship
between pressure, volume, temperature, and mass of a "perfect" gas.
MOLE FRACTION OF A GAS
At standard temperature and pressure (32°F and 29.92 in. Hg.) a mole of gas fills
22.4 liters. The ratio of the number of moles of the component gas to the number
of moles in the whole mixture is equal to the component's mole fraction. The mole
fraction of each constituent of a gas mixture must be known for calculation of the
apparent molecular weight of the mixture. This is done on a volume basis.
MOLECULAR WEIGHT OF A STACK GAS
The molecular weight of a stack gas is equal to the sum of the mole fraction of
each constituent multiplied by the molecular weight of that constituent.
1-1
-------
— apparent molecular weight of stack gas mixture
Mx = molecular weight of individual constituent
Bx = mole fraction of constituent gas
The apparent molecular weight of the stack gas is important for application of the
ideal gas law.
IDEAL GAS LAW
The ideal gas law defines the relationships among pressure, volume, temperature,
and mass of any gas.
(Eq.1-2)
M
where P= absolute pressure
V = volume of a gas
m = mass of a gas
M = molecular weight of a gas
T = absolute temperature (°K or °R)
R = universal gas constant (units
consistent with others used
in the equation)
ABSOLUTE TEMPERATURE
Temperature is a mass independent property related to the average kinetic energy
in a system due to molecular motion. Heat is a mass dependent property of the
system's total kinetic energy of molecular motion. The flow of heat in or out of a
system is determined by measuring changes in the temperature of the system.
Temperature is a factor in identifying the state of a gas system as defined by the
ideal gas law. Absolute temperature measure is given in °Kelvin (°C + 273.16) or
°Rankine (°F + 459.67).
ABSOLUTE PRESSURE
Fluids are subject only to shear and compression stress. Pressure is compression
stress expressed as the force applied per unit area.
Absolute pressure is "absolute zero pressure," the sum of the atmospheric
pressure and any gage pressure above or below atmospheric:
(Eq.1-3) P=Pb + Pg
where P — absolute pressure
Pfo = barometric pressure (atmospheric)
Pg = §age pressure (pressure measured by a gage,
higher or lower than atmospheric pressure)
1-2
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PITOT TUBE
The pilot tube is a simple device used to measure the velocity of a fluid flowing in
an open channel. The complexity of underlying fluid flow principles of pilot tube
gas velocity measurement are not apparent in the simple operation of this device. It
should, however, be considered and treated as a sophisticated instrument.
The pitot tube actually measures the velocity pressure of a gas stream (Figure
1-1). Gas streamlines, approaching a round object placed in a duct, flow around
the object except at point "P+ ." Here the gas stagnates, and the total pressure is
found. The difference between this total pressure and the static pressure (ps) is the
velocity pressure (A/>).
Figure 1-1. Gas stagnation against an object.
The static pressure in a gas stream is defined as the pressure that would be in-
dicated by a pressure gage if it were moving along with the stream so as to be at
rest or be relatively "static" with respect to the fluid.
stagnation static velocity
pressure pressure pressure
Figure 1-2. Components of total pressure.
1-3
-------
Bernoulli's Equation relates pitot tube velocity pressure to gas velocity in the
equation:
(Eq.1-4)
where vs — velocity of the stack gas
Kp = dimensional constant
Cp = pitot tube calibration coefficient
Ts — absolute temperature of the gas
Ps — absolute pressure of stack gas
Ms = apparent molecular weight of stack gas
This equation is derived in the appendixes.
DRY GAS METER CORRECTION FACTOR
The term "primary standard" is a theoretical expression. It implies absolute
measurement of a given variable. This is not possible in actual practice. We,
therefore, "designate" standards of measurement. The spirometer is the designated
standard for gas volume measurement. A volume measurement made by any device
other than a spirometer should be corrected to correspond with spirometer
readings. Volume readings made by the sampling train meter console dry gas meter
are correlated to spirometer volume by a correction factor. This factor is
determined empirically prior to using the meter in field work:
SV
(Eq.1-5) DGMCF=
DGMV
where DGMCF— dry gas meter correction factor
SV = spirometer volume
DGMV— dry gas meter volume
The DGMCF is then applied to correct volumes measured by the dry gas meter:
(Eq.1-6) DGMVx DGMCF= volume corrected to spirometer reading
ORIFICE METER
The simplest and most familiar type of orifice meter is a circular hole in a thin flat
plate held between flanges at a joint in a pipe (Figure 1-3). The plate is located 8
diameters upstream and 2 diameters downstream of any flow disturbance, perpen-
dicular to the pipe axis with the hole concentric to the pipe.
1-4
-------
S3
I
1
i
AH
!
ea
..... A,.-. •..•....•.......• .•..^...-.NZTT
x_
V.
orifice plate
manometer
Figure 1-3. Simple orifice meter.
The orifice creates a pressure differential between the two sides of the plate. This
pressure differential is related to the flow rate of gas through the orifice device:
(Eq.1-7)
Qm
= Km\
where Q^j = volumetric gas flow rate
AH = pressure differential across the orifice
Tm = absolute gas temperature (°R or °K)
Pm = absolute pressure (barometric) inches Hg or mm Hg
Kffi = proportionality factor determined by empirical calibration
AH
A term designated to describe the manometer setting (pressure differential across
the orifice) of a calibrated orifice meter. During calibration of the orifice meter,
AH defines a given flow rate through the meter. In field use, the nomograph is
used to calculate a desired AH, which correlates flow through the meter to the
velocity of gas entering the sampling nozzle. Gas velocity at the sampling nozzle is
thus indirectly determined by flow rate.
NOMOGRAPH
The stack sampling nomograph is essentially a slide rule. The nomograph solves
the isokinetic equation for EPA Method 5 sampling train. The flow rate through
the sampling train can then be adjusted to correspond to the stack gas velocity.
1-5
-------
A designated term used to describe the orifice meter manometer setting that will
allow 0.75 cubic feet/minute of dry air at 68°F and 29.92 in. of Hg to flow
through the meter. A condensed mathematical definition is given as:
(Eq.1-8)
where 0.9244 = a constant for conditions and units defined
= orifice meter calibration factor (see orifice meter)
1-6
-------
Nomenclature
An — sampling nozzle cross-sectional area
As — stack cross-sectional area
a — mean particle projected area
— percent moisture present in gas at meter
— 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% CO2
~ paniculate concentration corrected to 50% excess air
— equivalent diameter
— 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 CC>2 on wet or dry basis
Fd — F-factor using cs and O% on a dry basis
Fw — F-factor using cws and C>2 on a wet basis
Fo — miscellaneous F-factor for checking orsat data
— pressure drop across orifice meter for 0.75 CFM
flow rate at standard conditions
AH — pressure drop across orifice meter
j — equal area centroid
Kp — pitot tube equation dimensional constant
[g/g-mole (mmHg)"|
s_s v §/
(°K)(mm H20) J
English Units = 85.49 ft./sec.
(°K)(mm H20)
lb/lb-mole(in. Hg)
in. H2O)
1-7
-------
L — length of duct cross-section at sampling site
¥ — path length
L! — plume exit diameter
L-2 — stack diameter
m — mass
M(j — dry stack gas molecular weight
Ms — wet stack gas molecular weight
n — number of particles
NRC — Reynolds number
Oj — plume opacity at exit
O2 — in stack plume opacity
^atm ~~ atmospheric pressure
Pb — barometric pressure (PD = Patm)
Pm — absolute pressure at the meter
pmr — Pollutant mass rate
Ps — absolute pressure in the stack
^std ~~ standard absolute pressure
Metric Units = 760 mm Hg
English Units =29.92 in. Hg
Ap — gas velocity pressure
d) — standard velocity pressure read by the standard
pitot tube
Aptest ~~ gas velocity pressure read by the type "S" pitot
tube
q — particle extinction coefficient
Qs — 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
Tstd ~ standard absolute temperature
Metric Units - °20 °C + 273 = 293 °K
English Units = 68 °F + 460 = 528 °R
Vm — volume metered at actual conditions
Vm , — volume metered corrected to standard conditions
v.p. — water vapor pressure
vs — stack gas velocity
Volume H2O - Metric units = 0.00134 m3/ml X ml H2O
English units = 0.0472 ft.Vmlxml H2O
W — width of the duct cross-section at the sampling site
6 -- time in minutes
1-8
-------
Subscripts
atm — atmospheric
ave — average
b — barometric
d — dry gas basis
f - final
g - gage
i — initial
m — at meter
n — at nozzle
p — of pitot tube
s — at stack
SCF — standard cubic feet
std — standard conditions
w — wet basis
1-9
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Chapter 2
Basic Concepts of Gases
EXPRESSION OF GAS TEMPERATURE
The Fahrenheit and Celsius Scales
The range of units on the Fahrenheit scale between freezing and boiling is 180; on
the Celsius or Centigrade scale, the range is 100. Therefore, each Celsius-degree is
equal to 9/5 or 1.8 Fahrenheit-degree. The following relationships convert one
scale to the other:
(Eq.2-1) °F=1.8 °C + 32
(Eq.2-2) °C = (°F-32)/1.8
where °F = degrees Fahrenheit
°C = degrees Celsius or degrees Centigrade
Absolute Temperature
Experiments .with perfect gases have shown that, under constant pressure, for each
change in Fahrenheit-degree below 32°F the volume of gas changes 1/491.67.
Similarly, for each Celsius degree, the volume changes 1/273.16. Therefore, if this
change in volume per temperature-degree is constant, the volume of gas would,
theoretically, become zero at 491.67 Fahrenheit degrees below 32 °F or at a
reading of— 459.67 °F. On the Celsius or Centigrade scale, this condition occurs at
273.16 Celsius-degrees below 0°C, or at a temperature of -273.16°C.
Absolute temperatures determined by using Fahrenheit units are expressed as
degrees Rankine (°R); those determined by using Celsius units are expressed as
degrees Kelvin (°K). The following relationships convert one scale to the other:
(Eq.2-3) °fl=°F+459.67
(Eq.2-4) °X=0C + 273.16
The symbol T will be used in this outline to denote absolute temperature and t
will be used to indicate Fahrenheit or Celsius degrees.
EXPRESSION OF GAS PRESSURE
Definition of Pressure
A body may be subjected to three kinds of stress: shear, compression, and tension.
Fluids are unable to withstand tensile stress; hence, they are subject to shear and
compression only.
2-1
-------
Unit compressive stress in a fluid is termed pressure and is expressed as force per
unit area (e.g., lb/in.2 or psi, Newtons/m2 or Pa).
Pressure is equal in all directions at a point within a volume of fluid, and acts
perpendicular to a surface.
Barometric Pressure
Barometric pressure and atmospheric pressure are synonymous. These pressures are
measured with a barometer and are usually expressed as inches, or millimeters, of
mercury (Hg). Standard barometric pressure is the average atmospheric pressure at
sea level, 45° north latitude at 35 °F. It is equivalent to a pressure of 14.696
pounds-force per square inch exerted at the base of a column of mercury 29.92
inches high. Weather and altitude are responsible for barometric pressure varia-
tions.
Gage Pressure
Measurements of pressure by ordinary gages are indications of difference in
pressure above, or below, that of the atmosphere surrounding the gage. Gage
pressure, then, is ordinarily the pressure of the system. If greater than the pressure
prevailing in the atmosphere, the gage pressure is expressed as a positive value; if
smaller, the gage pressure is expressed as negative. The term, vacuum, designates a
negative gage pressure.
The abbreviation g is used to specify a gage pressure. For example, psig, means
pounds-force per square inch gage pressure. f
Absolute Pressure
Because gage pressure (which may be either positive or negative) is the pressure
relative to the prevailing atmospheric pressure, the gage pressure, added
algebraically to the prevailing atmospheric pressure (which is always positive), pro-
vides a value that has a datum of absolute zero pressure. A pressure calculated in
this manner is called absolute pressure. The mathematical expression is:
(Eq. 2-5) p=pb+p
O
where P — absolute pressure
Pfr = barometric pressure (atmospheric)
pa — gage pressure
The abbreviation, a, is sometimes used to indicate that the pressure is absolute.
For example, psia, means pounds per square inch absolute pressure. The symbol P
by itself, will also be used in this manual to indicate absolute pressure.
The absolute pressure allows conversion of one pressure system to the other.
Relationship of the pressure systems are shown graphically in Figure 2-1 using two
2-2
-------
typical gage pressures, (1) and (2). Gage pressure (1) is above the zero from which
gage pressures are measured, and, hence, is expressed as a positive value; gage
pressure (2) is below the gage pressure zero, and, therefore, is expressed as a
negative value,
Pg(l)
Gage pressure zero
ratm
Pgtt>
P(2)
Absolute pressure zero
Figure 2-1. Gas-pressure relationship.
Dalton's Law of Partial Pressure
When gases, or vapors (having no chemical interaction), are present as a mixture
in a given space, the prt jsure exerted by a component of the gas mixture at a given
temperature is the same as it would exert if it filled the whole space alone. The
pressure exerted by one component of a gas mixture is called its partial pressure.
The total pressure of the gas mixture is the sum of the partial pressures.
THE LAW OF IDEAL GASES
The Laws of Boyle and Charles
Boyle's Law states that, when the temperature (T) is held constant, the volume
(V) of a given mass of a perfect gas of a given composition varies inversely as the
absolute pressure, i.e.:
at constant T
where ex = proportional to
2-3
-------
Charles' Law states that, when the volume is held constant, the absolute
pressure of a given mass of a perfect gas of a given composition varies directly as
the absolute temperature, i.e.: PocT at constant volume.
The Law of Ideal Gases
Both Boyle's and Charles' Law are satisfied in the following equation:
(Eq.2-6)
M
where P —absolute pressure
V= volume of a gas
m = mass of gas
M = molecular weight of a gas
T = absolute temperature
R — universal gas constant
The unit of R depends upon the units of measurement used in the equation. Some
useful values are:
(1) 1544
(2) 21.83
(3) 554.6
(4) 82.06
(lb-mole)(°R)
(in. Hg) (ft?)
(lb-mole)(°R)
(mm Hg) (ft*)
(lb-mole)(°R)
(cm?) (atm)
(gm-mole)(°K)
In the above units of R:
V^ft3, cm2 for (4)
m = lb, g for (4)
M = lb/lb-mole, g/g-mole for (4)
T-=°R, °K for (4)
P=lb/ft2for(l)
= in. Hgfor (2)
- mm Hg Jor (3)
= atm for (4)
Any value of R can be obtained by utilizing the fact, with appropriate conversion
factors, that there are 22.414 liters per gm-mole or 359 ft.3 per Ib-mole at 32°F
and 29.92 in. Hg.
2-4
-------
CALCULATION OF APPARENT MOLECULAR WEIGHT
OF GAS MIXTURES
Using Dalton's law of partial pressure and the ideal gas law, the following equation
can be derived for calculating the apparent molecular weight of a gas mixture:
(Eq. 2-7) Mmix = EBXMX
where ^mix ~ o~ppo.rent molecular weight of a gas mixture
Bx= proportion by volume of a gas component
Mx = molecular weight of a gas component
In all other equations (except where specifically noted), the symbol M|will be used
to denote the molecular weight of a pure gas or a gas mixture. *
GAS DENSITY
Gas density can be determined by rearranging Equation 2-6 and letting density
Q = m/V:
(Eq.2-8) e=PM
RT
where Q = density
P= absolute pressure
M = molecular weight
T = absolute temperature
R = universal gas constant
A method of determining density at Ts (stack temperature) and Ps (stack pressure)
is to use the fact that there are 22.414 liters per gm-mole or 359 ft^ per Ib-mole at
32 °F and 29.92 in. Hg, and to use the ideal gas law correction.
VISCOSITY
Origin and Definition of Viscosity
Viscosity is the result of two phenomena: (a) intermolecular cohesive forces, and (b)
momentum transfer between flowing strata caused by molecular agitation perpen-
dicular to the direction of motion. Between adjacent strata of a moving fluid, a
shearing stress (T) that is directly proportional to the velocity gradient occurs
(Figure 2-2).
2-5
-------
Figure 2-2. Shearing stress in a moving fluid.
This is expressed in the equation:
(Eq.2-9)
dy
where gc = dimensional constant
T = unit shearing stress between adjacent layers of fluid
— = velocity gradient '
dy
fi = proportionality constant (viscosity)
The proportionality constant, /*, is called the coefficient of viscosity, or merely,
viscosity. It should be noted that the pressure does not appear in Equation 2-9
which indicates that the shear (T) and the viscosity (/^) are independent of pressure.
(Viscosity actually increases very slightly with pressure but this variation is negligi-
ble in most engineering problems.)
Kinematic Viscosity
Kinematic viscosity is defined according to the following relationship:
,.- V-
(Eq.2-10)
where
v = kinematic viscosity
fji - viscosity of the gas
Q - density of the gas
Note the absence of dimensions of force.
2-6
-------
Liquid Viscosity
In a liquid, transfer of momentum between strata having a relative velocity is small
compared to the cohesive forces between molecules. Hence, shear stress is .
predominantly the result of intermolecular cohesion. Because forces of cohesion
decrease rapidly with an increase in temperature, the shear stress decreases with an
increase in temperature. Equation 2-9 shows that shear stress is directly propor-
tional to the viscosity. Therefore, liquid viscosity decreases when the temperature
increases.
Gas Viscosity
In a gas, the molecules are too far apart for intermolecular cohesion to be effec-
tive. Thus, shear stress is predominantly the result of an exchange of momentum
between flowing strata caused by molecular activity. Because molecular activity in-
creases as temperature increases, the shear stress increases with a rise in the
temperature. Therefore, gas viscosity increases as the temperature rises.
Determination of Viscosity of Gases
The viscosity of a gas for prevailing conditions may be found accurately from the
following formula:
H° \273.2
where
fi = viscosity prevailing
IJLO = viscosity at 0°C and prevailing pressure
T = absolute prevailing temperature (°K)
n = an empirical exponent (n = 0.768 for air)
The viscosity of air and other gases at various temperatures and at a pressure of
1 atmosphere may be found in engineering tables.
SPECIFIC HEAT
The specific heat of a gas is the amount of heat required to change the
temperature of a unit-mass of gas one temperature-degree. Units of specific heat
are, therefore, (Btu/lb) (°F) or (calories/gm)( °C) depending upon the dimensional
system used.
Heat may be added while the volume or pressure of the gas remains constant.
Hence, there may be two values of specific heat: (a) the specific heat at constant
volume (Cv), and (b) the specific heat at constant pressure (C*).
Because the heat energy added at constant pressure is used in raising the
temperature and doing work against the pressure as expansion takes place, Cp is
greater than Cv.
2-7
-------
Determination of Specific Heat for a Gas Mixture
The specific heat for a mixture of gases may be calculated from:
(Eq.2-12) Cp(mix) = ZBxCp(x)
(Eq.2-13) Cv(mix) =
where Cp(mix) = specific heat at constant pressure for gas mixture
Cv(mix) = specific heat at constant volume for the gas mixture
Bx = proportion by volume of a gas component
Cp/x\ = specific heat at constant pressure for a gas component
GV(X) = specific heat at constant volume for a gas component
For ordinary temperature (for example, about 80 °F as experienced at the meter-
ing device in atmospheric or source sampling work) the specific heats may be
assumed to be constant.
REYNOLDS NUMBER
Definition
A typical inertial force per unit volume of fluid is Qv/gcL; a typical viscous force
per unit volume of fluid is iw/gcL?. The first expression divided by the second pro-
vides the dimensionless ratio known as Reynolds Number:
(Eq.2-14) NRe=^-
/*
where Q — density of the fluid (mass /volume)
v — velocity of the fluid
gc = dimensional constant
L — a linear dimension
fi = viscosity of the fluid
NRe = Reynolds Number
The larger the Reynolds Number, the smaller is the effect of viscous forces; the
smaller the Reynolds Number, the greater the effect of the viscous forces.
The linear dimension, L, is a length characteristic of the flow system. It is equal
to four times the mean hydraulic radius, which is the cross-sectional area divided
by the wetted perimeter. Thus for a circular pipe, L= diameter of the pipe; for a
particle settling in a fluid medium, L = diameter of the particle; for a rectangular
duct, L = twice the length times the width divided by the sum; and for an anulus
such as a rotameter system, L = outer diameter minus the inner diameter.
Laminar and Turbulent Flow
In laminar flow, the fluid is constrained to motion in layers (or laminae) by the
action of viscosity. The layers of fluid move in parallel paths that remain distinct
from one another; any agitation is of a molecular nature only. Laminar flow occurs
2-8
-------
when Reynolds Number for circular pipes is less than 2000 and less than 0.1 for
particles settling in a fluid medium.
In turbulent flow, the fluid is not restricted to parallel paths but moves forward
in a haphazard manner. Fully turbulent flow occurs when Reynolds' Number is
greater than 2500 for circular pipes and greater than 1000 for settling particles.
Figure 2-3. A tube of flow used in proving the equation of continuity.
THE EQUATION OF CONTINUITY*
In Figure 2-3 we have drawn a thin tube of flow. The velocity of the fluid inside,
although parallel to the tube at any point, may have different magnitudes at dif-
ferent points. Let the speed be t/j for fluid particles at X and 1/2 for fluid particles
at Y. Let Aj and A2 be the cross-sectional areas of the tubes perpendicular to the
streamlines at the points X and Y, respectively. In the time interval A£, a fluid ele-
ment travels approximately the distance v&i . Then the mass of fluid Am crossing
Aj in the time interval is approximately
Any =
or the mass flux Any /At is approximately
Amj
A*
= Q1A1v1
*Adapted from D. Halliday and R. Resnick, Physics for Students of Science and Engineering,
Combined Edition, New York, John Wiley and Sons, Inc., 1965, pp. 374-378. Used by permission
of the publisher.
2-9
-------
We must make At small enough so that in this time interval neither v nor A
varies appreciably over the distance the fluid travels. In the limit as Af — O, we
obtain the precise result
= QjAjvj at X.
dt
Now at Y the mass flux is correspondingly
dm 2
~diQ2 2
where Q\ and g£ are tne fluid densities at X and Y respectively. Since no fluid can
leave through the walls of the tube and there are no "sources" or "sinks" wherein
fluid can be created or destroyed in the tube, the mass crossing each section of the
tube per unit time must be the same. Hence, dmi/dt = dm,2/dt. Then
(Eq.2-15) QjAjVj = On^o^?
QAv= constant
This result is called the equation of continuity of mass flow. It expresses the
law of conservation of mass in fluid dynamics.
If the fluid is incompressible, then QJ = Q2 and the equation takes on the
simpler form:
(Eq.2-16) Av= constant
= A2V2
BERNOULLI'S EQUATION
A fundamental equation of fluid dynamics is Bernoulli's Equation. It is essentially
a statement of the work-energy theorem for fluid flow.
Consider the nonviscous, steady, incompressible flow of a fluid through the
pipeline or tube of flow in Figure 2-4. The portion of pipe shown in the figure has
a uniform cross section A2 at the left.
2-10
-------
Figure 2-4. A portion of fluid (cross-shading and horizontal shading) moves
through a section of pipeline from position (a) to position (b).
It is horizontal at elevation yj above some reference level. It gradually widens and
rises and then has a uniform cross section A2 (at the right of the figure). It is
horizontal at elevation y2- Let us concentrate our attention on the portion of fluid
represented by both cross-shading and horizontal shading and call this fluid the
"system." Consider then the motion of the system from the position shown in (a) to
that in (b).
At all points in the narrow part of the pipe, the pressure is pj and the speed vj.
At all points in the wide part the pressure is p2 and the speed t/2- The left portion
of the system (cross-shading, Figure 2-4a) advances a distance A//, parallel to an ex-
ternal force pjA j supplied by the fluid to its left, so that the work done on the
system is pjAjAlj. The right portion of the system (cross-shading, Figure 2-4b) ad-
vances a distance A/2 against an oppositely directed force p2^2 supplied by the
fluid beyond, so that the work done by the system is p2A2^2- Hence, to move the
system from position (a) to position (b), a net amount of work must be done on the
system by the pressures applied to it equal to />j^jA/j-p2^2^2-
-<4/Al] and A£Al£ are the volumes of the two cross-shaded regions. These
volumes are equal because the fluid is incompressible. In fact, if we let m be the
mass of either cross-shaded region and take fluid density to be r then
2-11
-------
(Eq.2-17) AiAl! = A2A12 = —
(Eq.2-18) (pj — p2) — —net work done on system.
If our pipe has a continuously variable cross section, this analysis can be made
exact by considering the process in the limit as Alj, A12, and Af shrink to zero at
the points 1 and 2. The result is the same as before.
If the flow is nonviscous, the net work done on the system by pressure must equal
the net gain in mechanical energy. The horizontal shaded portion of the fluid does
not change at all in either kinetic or potential energy during the flow from (a) to
(b). Only the cross-shaded portions contribute to changes in mechanical energy. In
fact, 1/^mv2^ — fimv/^ = net change of kinetic energy, and mgy2 ~ mgyi = net
change in gravitational potential energy, where m is the mass in either cross-shaded
region, and g is the gravitational constant. Hence,
(Eq.2-19) (Pj ~p2)— = (K mv22 - y, mvfi + (mgy2 -
or on rearranging terms,
(Eq.2-20) pj + y2 QVj2 + Qgyj = p2+!/2 Qv22 + Qgy2
Since the subscripts 1 and 2 refer to any two locations along the pipeline, we can
drop the subscripts and write
(Eq.2-21) p+\k QV2 + Qgy = constant.
Either Equation 2-20 or Equation 2-21 is called Bernoulli's Equation for steady,
nonviscous, incompressible flow. It was first presented by Daniel Bernoulli
(1700-1782) in his Hydrodynamica in 1738.
Bernoulli's Equation is strictly applicable only to steady flow. The quantities in-
volved must be evaluated along the same streamline; hence, the constant Equation
2-21 is not the same for all streamlines. In our figure the streamline used is along
the lower boundary of the tube of flow or pipeline.
In the special case of fluid statics, Bernoulli's Equation still holds. If the fluid is
at rest then vj — 0 = v2 and Equation 2-20 becomes
(Eq.2-22) Pj + Qgyj =P2 + Qgy2
The pressure that would be present even if there were no flow is denoted as the
static pressure; the term 1/2 QV^ is called the dynamic pressure.
2-12
-------
Chapter 3
The EPA Method 5 Sampling Train
Specialized equipment is required for performing the experimental procedures
outlined in Federal Reference Methods 5 and 8. This equipment may be either
constructed by the source tester or purchased from a commercial vendor. It is more
common today to find stack test consulting companies and agency test teams using
the commerical apparatus. A list of vendors currently marketing such equipment
may be found in the appendix. Construction details for the Method 5 sampling
train may be found in the EPA publication APTD 0581 available from the
National Technical Information Service(NTIS).
The purpose of this chapter is to provide the reader with some insight into the
design and construction of source sampling apparatus. A proper evaluation of
sampling equipment must consider both the equipment's ability to conform to
Federal or State construction guidelines and its actual utility in the field. This
discussion should assist the reader in purchasing the source sampling train or in the
construction of such a system.
3-1
-------
\
Figure 3-1. EPA Method 5 paniculate sampling train
Sampling nozzle
Sampling probe sheath
Heated sample probe liner
Cyclone assembly (proposed regulations do not require this cyclone)
Out of stack filter assembly
Heated filter compartment maintained 120°C±14°C (248°F±25°F)
(or temperature specified in 40CFR subpart)
Impinger case
First impinger filled with HgO (100 ml)
Greenburg-Smith (or modified Greenburg-Smith) impinger filled with HgO (100 ml)
Third impinger —dry
Fourth impinger —filled with H20 absorption media (200-300 gm)
Impinger exit gas thermometer
Check valve to prevent back pressure
Umbilical cord —vacuum line
Pressure gage
Coarse adjustment valve
Leak free pump
By-pass valve
Dry gas meter with inlet and outlet dry gas meter thermometer
Orifice meter with manometer
Type S pitot tube with manometer
3-2
-------
THE SOURCE SAMPLING NOZZLE
The source sampling nozzle must have a sharp outside edge (taper angle <30°)
and a button-hook or elbow design. This profile creates the least amount of disturb •
ance to the gas streamlines. Figure 3-2 illustrates the preferred sampling nozzle
shape.
Sampling nozzle
Figure 3-2. Preferred sampling nozzle shape (assembled with Type S pilot tube).
The nozzle interior diameter must be accurately calibrated following the procedure
given in the calibration section of this manual. Manufacturer calibration is only a
nominal approximation, and calibration of nozzle interior diameter should be
checked with a micrometer before the nozzle is placed on the sampling probe at
the test site. The sampling nozzle interior diameter must be round and uniform
throughout its entire length. If the tip is out-of-round it must be rounded, ground
to a sharp edge, and recalibrated. If the nozzle has obvious flat places in its body it
should be replaced with a nozzle of uniform diameter. The nozzle must properly
align with pilot tube sensing orifices so that one line can be drawn through the
central axis of the interior nozzle diameter opening and of the pilot orifice. The
nozzle must not be too short or too long; if the central axis of the pilot tube is not
on the same line as the nozzle diameter, it must be parallel and not more than V4"
off-center (Figure 3-3).
3-3
-------
Type S pilot tube
I
t
Sampling nozzle
Figure 3-3. Pilot tube-nozzle separation and alignment.
A nozzle not meeting all these criteria does not comply with Federal Register
specifications and can create sampling errors. Sampling nozzles constructed of
stainless steel or quartz glass (for special applications) are required.
THE PITOT TUBE
The Stausscheibe or Type S pilot tube is most frequently used in conjunction with
the Method 5 or Method 8 sampling train. The Type S pilot tube has several ad-
vantages thai makes il altractive for source sampling applicalions:
•It is compact. It is easy lo inseri inlo a 3" sampling porl.
•Il reiains calibraiion in abusive environmenis.
•It has large sensing orifices. This minimizes ihe chance of plugging in heavy
paniculate conceniraiions.
•It indicates a higher Ap reading lhan a slandard pilol tube which is
beneficial in low gas velocity situalions.
The Stausscheibe pilol is not a designaled slandard. It musl be calibrated
against a standard pitot static tube with a known calibration factor. Manufacturer
calibration coefficents are not sufficient. The lack of slandard conslruclion delails
and the high sensitivity to gas turbulence and orientation in the gas slream require
that the Type S tube be calibrated in the configuration intended at the sampling
site.
The construction of the Type S tube must be checked before calibration.
Calipers are used to check that the tubes are in line at the sensing orifice. The
dimensions taken with the calipers must form a rectangle with parallel sides. If
these dimensions show the A and B legs to be improperly aligned, the Type S lube
3-4
-------
must be corrected. Small misalignment of tube axis (A or B) can cause sufficient
gas turbulence to effect pilot tube calibration. The tube should be made of
stainless steel or quartz (for high temperature applications).
SAMPLING PROBE—PITOT TUBE ASSEMBLY
The pitot tube should be firmly attached to the sampling probe and properly
oriented. The probe-pitot assembly must be arranged in such a way that the pitot
tube body will be oriented perpendicular to the stack wall when sampling. The
sensing orifices will then be perpendicular to the flow of gas parallel to the stack.
This orientation is necessary for precise, accurate gas velocity readings. A Type S
pitot tube incorrectly oriented to the stack gas can cause significant errors in gas
velocity readings (Figure 3-4).
1.O6
1.04
1.O2
l.OO
.98
.96
.94
>. .92
.90
.88
.86
.84
• 6 m/sec
A 17 m/sec
-SO -40 -3O -2O -IO
1O
20 30 40 SO
6, degree
Adapted from E. F. Brooks and R. L. Williams, Flow and Gas Sampling
Manual, EPA-600/2-76-20S, July 1976, p. 59.
Figure 3-4. Type S pitot probe orientation sensitivity data.
The pitot must be firmly attached to the probe so it will not slip accidently into
misalignment.
The stainless steel probe sheath should be of 316 stainless steel or equivalent. The
sheath should be at least 3 inches from the pitot tube sensing orifices, and any
nozzle must be at least % inches from this orifice when attached to the probe
(Figure 3-3). A small hole should be drilled into the stainless sheath to equalize any
pressure differential that might allow dilution air to be pulled into the sampling system.
3-5
-------
The sheath is designed to protect the heated liner. Tolerances in the sheath
should be such that probe liner heating element short circuits are not a problem
during normal operation. The liner should be borosilicate glass for sampling stack
gases below 700°F. Quartz glass may be used in the sheath for temperatures up to
1400°F. Stainless steel liners are subject to corrosion by hot, acidic stack gases.
They should be a last choice except for very difficult sampling applications or for
sampling probes over 11 feet long. A liner heated by an easily-removed, reusable
heating element can be replaced at minimum cost. The probe heater should be
calibrated so that the outlet gas temperature at the filter is known.
The liner should be cleaned with a probe brush. A brush of non-reactive nylon
and stainless steel with strongly attached bristles is appropriate (bristles must not
fall into the sample). It should be attached to a stainless steel or teflon tube that
can be telescoped with additional sections.
THE SAMPLING CASE
A lightweight, easily adaptable sampling case is an asset during sampling ex-
periments. A well-designed sample case can be made from lightweight material and
yet withstand source sampling abuses. The case should incorporate solid construc-
tion and well-insulated electrical connections, and it should be usable in either ver-
tical or horizontal positions. The filter compartment must have a calibrated ther-
mostat. A positive locking system to prevent probe-pitot rotational or tilt misalign-
ment in the stack is also necessary. The probe sheath should be able to be inserted
in the sample case so that there is no accidental glass breakage. An example of the
described system is illustrated in Figure 3-5.
Heated filter
compartment
Umbilical vacuum
connection
Impingers
Amphenol
Figure 3-5. Sampling case. '
A single-point swivel suspension system for the sample case is advantageous in tight
work area situations.
3-6
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TRAVERSE SUPPORT SYSTEM
A monorail support is versatile and lightweight. An inexpensive monorail support
system with a lubricated roller hook can be easily assembled. It may be used at a
variety of sampling sites for horizontal or vertical duct traverses. An entire system
can be cheaply assembled with some lengths of chain, double-ended snaps, angle
iron, and eye bolts. A simple platform constructed of plywood and 2 X 4's will be
sufficient in many situations where a monorail is not practical.
SAMPLE CASE GLASSWARE
There are several types of impinger-filter sets available for source sampling trains.
Sample case impingers and filter holders are generally made of Pyrex glass, but
special situations could call for the stainless steel or Lexan plastic equipment. Glass
has obvious advantages and should be used unless unusual situations arise. The
glassware is available in standard ball joint fittings that are sealed with vacuum
grease and clamped together or in a newer screw-joint sealed with a compressible
teflon-rubber ring. The newer screw-joint fittings increase breakage; however, they
are easier to clean, and grease contamination of the sample is never a problem.
THE UMBILICAL CORD
The vacuum sampling line, pilot tube lines, and electrical wiring are wrapped into
an "umbilical cord" extending from the meter console to the sample case. These
lines are encased in tape or shrink tubing to protect them and eliminate clutter at
the sample site. The vacuum line should be of high-vacuum rubber tubing. The
pilot lines are best constructed of heavy-ply tygon tubing. These materials make
the umbilical cord heavier, but they are not easily melted, burned, or cut. Sample
cords made of polymeric materials can be easily damaged without notice and then
begin to leak. The electrical wires should have thick insulation to prevent fraying
in heavy use. They should be color coded and attached to an Amphenol connection
for easy hookup to the sample case.
THE METER CONSOLE
The meter console is the center of the sampling system. A packaged pump-dry gas
meter-orifice system is easiest to handle, but there are many suitable variations in
use. The system must have a leak-free pump to draw an isokinetic sample. A fiber
vane, oil lubricated pump, or diaphragm pump capable of creating an absolute
pressure of < 3 inches of Hg (< 30 inches Hg gage) is recommended. A fiber vane
pump is more desirable than a diaphragm pump, because it does not give "pulses"
of gas that can create errors in the operation of the dry gas meter.
The pump should force gas into the dry gas meter inlet, not pull it through the
meter outlet. The dry gas meter sliding vane seals are adversely affected when
under vacuum, so a vacuum gage should be in the system to measure pressure drop
across the sampling train.
3-7
-------
The dry gas meter must be accurate. The manufacturer supplies a nominal
calibration curve with the meter which should be rechecked before using the meter.
A dry gas meter correction factor developed by calibration against a spirometer or
wet test meter is important for volume readings from the meter. The meter dial
face should measure 0.1 cubic feet of gas per revolution. This gives the most
precise volume reading.
The differential pressure gage recommended in the Federal Register is an oil
manometer. The manometer must be capable of measuring the velocity pressure to
within 1.3 mm (0.05 in.) water column. The oil manometer is a secondary stan-
dard and is very accurate. A Magnehelic gage may be used if it is calibrated before
a test series, then checked after each test series against an oil manometer. The
Magnehelic gage must be calibrated and checked at three Ap readings representing
the range encountered at the source. The Magnehelic gage and oil manometer
must agree within 5 percent for the Magnehelic gage to be considered in proper
calibration.
The meter console or equivalent apparatus must be capable of monitoring and
maintaining all the equipment temperatures in addition to measuring stack gas
temperature. Bimetallic thermometers in the sample case for impinger gas exit
temperature are acceptable if they are precise to within 1 °C (2°F). The tempera-
ture at the dry gas meter and at the filter compartment must be measured with a
precision of 3°C (5.4°F). Some method of regulating the calibrated probe liner
heater and filter heater must be incorporated into the temperature control system.
The stack gas temperature meter must measure gas temperature to 1.5 percent of
the minimum absolute stack gas temperature. A meter console using thermocouples
for these operations must have the thermocouples calibrated regularly and checked
before each use.
THE NOMOGRAPH
A number of nomographs are available commercially. The nomograph makes
several assumptions in its calculations, but these assumptions may not always hold
true for all sampling situations. The alignment and accuracy of nomograph func-
tions should be checked using the procedures given in this manual. A pocket
calculator can solve the isokinetic equation accurately and inexpensively.
ALTERNATIVE METHODS AND EQUIPMENT
There are a number of alternative methods for isokinetic sampling of stack gas par-
ticulates. The Japanese and West German methods have received attention in many
countries, and the American Society of Mechanical Engineers has also developed
isokinetic sampling methods. These alternative methods may be highly attractive
for some situations. This manual and the Federal Register reference methods
recognize only the methods described herein. The use of methods other than those
described in the Federal Register requires special approval from the regional ad-
ministration assessing the effects that alternative methods may have on sampling
results.
3-8
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Chapter 4
Calibration Procedures
Source sampling equipment must be properly calibrated before it is used in the
field. Systematic errors will result throughout the testing procedure as a result of
uncalibrated or improperly calibrated equipment. Without calibration, the stack
tester cannot sample isokinetically in any of his source tests, and he cannot correct
the mass emission rate data if the equipment is calibrated after the test. It is
therefore crucial that the apparatus used for stack testing be carefully checked. A
manufacturer's calibration value or guarantee should not be trusted. It is not un-
common to find miscalibrated apparatus supplied by a vendor, and over extended
use instrument calibration values can change.
A careful experimentalist always double checks his apparatus. Weeks of work
may otherwise be questioned or may need to be redone. This section gives calibra-
tion procedures and design specifications for equipment commonly used in the
source test. The procedures should be followed after receipt of new equipment and
should be repeated after periods of extended use.
CALIBRATION OF THE SOURCE SAMPLING METER CONSOLE
The gas meter and orifice meter of a sampling console may be calibrated during
one procedure. The calibration described in this section may be performed using a
standardized dry gas test meter or wet test meter. The sampling console must be
thoroughly leak tested before calibration.
Calibration Equipment
1. Calibrated test meter
a. Wet test meter (correction factor should be 1.0 for
wet test meter)
b. Standardized dry gas test meter
2. Sampling meter console
a. Dry gas meter
b. Orifice meter
3. Stopwatch
4. Leak-free pump (fiber vane, preferably)
5. Vacuum tubing
6. Swagelock connections
7. Leak test liquid
Meter Console Leak Test
The meter console pump, dry gas meter, and orifice meter must be leak tested
before calibration. This leak test can be accomplished by individually testing each
4-1
-------
piece of equipment or by leak testing the entire assembly. The Federal Register
suggests a procedure for leak testing the assembled pump, dry gas meter, and
orifice configuration (Figure 4-1). The following procedure, however, does not
apply to diaphragm pumps.
Rubber stopper
By-pass valve
Orifice
Closed -s*"
• Vent
iihlu
Orifice
manometer
Vacuum gauge
Air-tight pump
Figure 4-1. Leak check for the Method 5 meter console.
1. Plug the orifice meter outlet with a one-hole rubber
stopper that has a rigid tube through the hole.
2. Attach a length of rubber tubing (an inline toggle valve in
the tubing would be helpful).
3. Disconnect the static pressure side tubing of the orifice
manometer and close off the tube. Leave the static tap of
the manometer open to a vent position.
4. Completely open the bypass valve by turning it counter-
clockwise to a lock position; close the coarse adjustment
valve.
5. Blow into the rubber tubing, plugging the orifice until the
manometer shows a pressure differential greater than 6 in. H20.
6. Seal the tubing (close toggle valve). The manometer
reading should remain stable at least 1 minute.
7. If a leak occurs, completely disconnect the orifice
manometer and seal the orifice meter. Pressurize the
system using a small pump and find the leak with leak
test solution.
Meter consoles with diaphragm pumps can be leak checked by pulling an air
sample through a wet test meter-pump-dry gas meter setup. The leak rate should
not exceed 0.0057 mVmin. (0.02 cfm).
4-2
-------
Meter Console Calibration
The meter console calibration is accomplished with the equipment assembled as
shown in Figure 4-2.
By-pass valve
Vacuum gauge
Orifice
manometer
Air-tight pump
Figure 4-2. Meter console calibration assembly.
The wet test meter should have a correction factor of 1. (A standardized dry gas
meter may also be used to calibrate the meter console.) The calibration of the
meter console dry gas meter and orifice meter is accomplished by passing a known
volume of dry air through the test meter at a number of different pressure differen-
tials on the orifice manometer.
In the calibration procedure:
1. Establish a pressure differential (AH) across the orifice
meter with the pump and the coarse and fine adjustment
valves.
2. Accurately record the dial readings for the wet test meter
and dry gas meter while simultaneously starting a
stopwatch.
3. Draw a predetermined volume of air (e.g. 5 cubic feet)
through the test meter. Record all temperatures during
the calibration run.
4. Stop the pump when the predetermined volume has been
reached on the wet test meter; simultaneously record the
total elapsed time.
5. Make all calculations on the calibration form for this
procedure (Figure 4-3).
Note: The standard temperature given by APTD-0576 (70°F) has
since been changed to 68 °F, although the publication itself does not
reflect this change.
4-3
-------
METER CONSOLE CALIBRATION
Name.
Date
Console no.
Dry gas meter no.
Dry gas meter correction factor
Wet test meter no..
Barometric pressure. l'\y
Correction factor.
in. Hg previous calibration and date.
Orifice
manometer
setting,
AH,
in. H20
0.5
1.0
2.0
1.0
li.O
8.0
Gas volume
wet test
meter
\',
f,3
5
5
10
10
10
10
Gas volume
drv gas
meter
V i
ft»
Temperature-
Wet
Meter
t..,,
°F
Drv gas meter
Inlet
t ..
°F
Outlet
t ,
°F
Average
t ,
°F
Time
0
min
Average
t
^H@
Calculations
AH
o.:>
1 0
2.0
!.()
().()
8.0
AH
IS fi
().()3(uS
0.()7.'57
0.1-17
0.29-1
0.131
0.588
•>
VwPb(td + 460)
/„ \H \ / \
vd(pb + H'iv + 4601
l\ 1
V 13.6 A /
AH@
0.0317 AH f (tw + 460)6> "|2
- - -
PK(t j + 460) V
ov a '««/ |_ » w J
7 = Ratio of accuracy of wet test meter to dry test meter. Tolerance = ± 0.02.
AH^ = Oiificc pressure differential that gives 0.75 cfm of air at 68°Fand 29.92 inches of mer-
cury. in. Ms>0. 'I olerance = ± 0.15 inches.
Orifice AH^ should fall between 1.59 2.09 inches, or modification may be necessary for some
sampling situations.
Figure 4-3. Form for meter console calibration
4-4
-------
CALIBRATION OF TEMPERATURE MEASUREMENT DEVICES
The Method 5 source sampling system requires gas temperature measurements at
several locations. The temperature measurements are important for correcting
stack gas parameters to standard condition. Accurate measurement within the
tolerance given in the Code of Federal Regulations is essential. Procedures are
given here for calibrating general types of temperature sensor devices. Manufac-
turer recommendations for special temperature sensors should be carefully
followed.
Temperature Reference
A commercially available mercury thermometer capable of ± 1 ° sensitivity is suffi-
cient for calibration purposes. The thermometer should be immersible in ice water,
boiling water, hot mineral oil, or a tube furnace. The thermometer scale should
cover the range of anticipated source temperatures.
Bimetallic Thermometer Calibration
Dial or bimetallic thermometers are used for temperature measurement in several
train locations. Adjustable dial thermometers are calibrated by immersion in a
water bath along Wjith the mercury thermometer. Temperature readings should be
taken at several points on the dial thermometer scale, and its reading should be set
to correspond with the corrected mercury thermometer measurement (adjusted for
elevation above sea level). Non-adjustable dial thermometers must agree with the
corrected mercury thermometer temperature within 3°C (5.4°F), if used at the
filter heater compartment, and within 1°C (2°F) when used at other locations in
the sampling train.
It is unlikely that a dial or a bimetallic thermometer would be used to monitor
in-stack gas temperature at most sources. If either is used for stack measurements,
it must be calibrated to read stack temperature to within 1.5 percent of the
minimum absolute stack gas temperature.
Thermocouples
An electromotive force is produced when two connected, dissimilar metal wires are
subjected to temperature variations. The electromotive force (EMF) is fixed for a
given combination of metals and is proportional to the temperature of the metal
wires at the measurement junction. A cold or reference junction is maintained at
the metering device. Potentiometers or millivoltmeters are commonly used to
measure EMF. The voltage signals are, today, usually converted to read directly in
degrees on either an analog or digital meter.
Thermocouple wires are necessarily thin to speed response time and increase
EMF sensitivity. They must be thoroughly inspected on a routine basis. Any frayed
or damaged wire should be replaced or repaired. Insulation must be complete, or
wires could short against metal surfaces. The thermocouple junction should be
either welded or silver-soldered.
4-5
-------
The thermocouple should be calibrated with the millivoltmeter that will be used
in the field. The voltmeter should first be zeroed and calibrated according to the
manufacturer's instructions. The following procedure should then be followed:
1. Connect the meter to the thermocouple.
2. Check the thermocouple reading with that of a mercury thermometer at
several readings:
a. boiling water
b. ice point
c. ambient air
If the temperature at the stack is greater than that of boiling water, several
calibration points across the anticipated temperature range should be made. This
may be done by using hot mineral oil, tube furnace, or another apparatus that
allows thermocouple and mercury thermometer comparison. The thermocouple
should be thoroughly cleaned after it is calibrated in a material such as mineral
oil. Do not immerse ceramic-covered thermocouples in a liquid calibration
medium: they absorb the liquid, and that can affect reading during calibration or
in field use.
3. Record the data (Figure 4-4).
4. Make the proper adjustments (if possible) on the voltmeter to read the
proper temperatures.
5. If the meter cannot be adjusted to reflect the proper temperatures, con-
struct a calibration curve and include it in your field notebook.
4-6
-------
TEMPERATURE CALIBRATION
Name
Barometric Pressure_
Date
Land Elevation.
ICE BATH
Hg in Glass
Thermometer
Temperature
°C
°K
OF
°R
Corrected Hg
in Glass
Temperature
°C
°K
OF
°R
Temperature Devi
Identification No.
Temperature
°C
0 K
ce
o F
°R
BOILING WATER BATH
Hg in Glass
Temperature
°C
°K
oF
°R
Corrected
Temperature
°C
°K
OF
°R
Device
No.
°C
0 K
o F
0 R
MINERAL OIL BATH
Point
1
2
3
4
Hg in Glass
Temperature
°c
°K
OF
°R
Corrected
Temperature
°C
°K
oF
°R
Device
No.
°c
°K
OF
°R
Figure 4-4. Form for temperature calibration.
4-7
-------
CALIBRATION OF THE TYPE S (STAUSSCHEIBE) PITOT TUBE
The Type S pitot tube has several advantages as a gas velocity pressure measure-
ment instrument in particulate-laden gas streams. The Type S tube is compact.
Separately or attached to a sampling probe, the tube fits easily into a 3-inch
diameter sampling port. The Type S pitot tube maintains calibration in abusive
environments, and its large sensing orifices minimize plugging by particulates. The
Type S pitot tube also gives a high manometer reading for a given gas velocity
pressure, which is helpful in stacks with low gas velocity. These features make the
Type S pitot tube the most frequently used source sampling pitot tube.
The Type S pitot tube construction details should be carefully checked before
calibration. The tube should be made of stainless steel or quartz (for high
temperature gas streams) with a tubing diameter (Df) between 0.48 and 0.95 cm
(3/16"-3/8"). The distance from the base of each pitot tube leg to the plane of the
orifice opening (PA>PB) should be equal (Figure 4-5).
Longitudinal %
tube axis
I
A-side plane
D
t
Figure 4-5. Type S pitot tube leg alignment.
P^ and PR should be between 1.05 and 1.50 times the tubing diameter. Pitot tube
orifice face openings should be properly aligned as shown in Figure 4-6. Misalign-
ment of these openings can affect the pitot tube calibration coefficient and should
be corrected before calibration.
4-8
-------
Transverse tube axis
Face openings
( planes —*
(a)
Longitudinal
tube axis —>
*
*
B
A or B
A-side plane
PA
B-side plane
(b)
-e
(c)
Figure 4-6. Type S pilot tube orifice alignment.
Calibration Equipment
1. Type S pitot tube assembled in the configuration anticipated for
sampling. Both legs A and B permanently identified.
2. Inclined manometer with a sensitivity to 0.13 mm (0.005 in.) H^O.
3. Standard Pitot Tube
a. Standard pitot-static tube with NBS-traceable calibration
coefficient.
b. Standard pitot-static tube constructed as shown in Figure 4-7. A
pitot tube designed according to these criteria will have a baseline
calibration coefficient of 0.99 ± 0.01.
4-9
-------
3=5
I
t
\
Curved or mitered junction
Static holes (-0.1D)
Hemispherical tip
c
I
s
I
a
to
Figure 4-7. Standard Prandtl pitot static tube.
4. Calibration Duct
a. Minimum duct diameter cross-section must be 30.5 cm (12 inches).
b. Cross-section constant over a distance greater than 10 duct
diameters.
c. Entry ports arranged so that standard pitot and Type S pitot are
reading gas pressure at the same point in the duct.
d. Flow system capable of generating a gas velocity of approximately
915 m/min. (3000 ft./min.). The gas flow must be constant with
time for steady flow. There must be no cyclonic gas flow in the
duct.
e. If a multipoint calibration is performed, the duct gas velocity
should be variable across the range of 180 to 1525 m/min (600 to
5000 ft./min.).
5. Support system to assure that pitot alignment is level and parallel to the
duct axis.
6. Tubing and quick connection fittings.
7. Barometer.
Calibration Procedures
The duct gas flow system should be established at a steady flow rate and should be
checked to insure that there is no cyclonic gas flow. The pressure differential gage
should be thoroughly checked for proper zero, level, fluid density, and volume, and
it should be set up on an area free of vibration. The pitot tube lines should be
arranged so that they may be easily and quickly switched from one pitot tube to
another. Always leave manometer connections set and switch lines at the pitot
tube.
4-10
-------
1. Leak test the pilot tubes and tubing by sealing the pitot tube im-
pact opening and then establishing a positive pressure at the opening
greater than 7.6 cm (3 in.). The manometer pressure should remain
stable for at least 15 seconds. Repeat the procedure for the static pres-
sure side of the pitot tube, using negative pressure. Perforrh this check
for all pitot tubes used in the calibration.
2. Using the standard pitot tube, measure the gas velocity pressure at the
center of the calibration duct. Simultaneously, measure gas tempera-
ture. The sensing orifice must be parallel to the duct axis and perpendicular
to the gas flow (Figure 4-8).
Standard pitot tube
Inclined manometer •
Figure 4-8. Pitot tube position in duct.
The standard pitot tube entry port should be sealed around the tube,
with no sealing material protruding into the duct, and the Type S pitot
tube port should be sealed.
3. Record all data (Figure 4-10), and then disconnect the standard pitot
tube from the differential pressure gage, remove the tube from the
duct, and seal the port.
4. Assemble the Type S pitot tube and accessories to minimize aero-
dynamic interferences (Figure 4-9).
4-11
-------
hi J
k
«d
—
IDt Type S pilot tube (~
T x > 1.90 cm (% in.) for Dn =
Sampling nozzle ^.
*)
1.
^
?
W>7.62 cm
I^^J
Thermocouple
A ! Dt TypeSpitot
tube
( I
\ Sample
Z>1.90 cm (34 in.)
Y> 7.62 cm (3 in.) •
&
Z>5.08 cmi
Thermocouple
(2 in.)
1
Type S pilot tube
4
Sample
probe
Figure 4-9. Configurations for minimum interference.
A very large sampling assembly can disturb the gas flow in small ducts.
If the area of the assembled probe-pitot tube is greater than 2 per-
cent of the duct cross-sectional area, the assembly should be calibrated
in a larger test section, or the Cp should be corrected for blockage
(see 40 CFR 60.46, paragraphs a-f).
4-12
-------
5. Connect the Type S pitot tube to the differential pressure gage and
insert the tube assembly into the duct. The Type S pitot tube must
measure the gas velocity pressure at the same point in the duct as the
standard pitot tube, and the pitot leg A must be properly aligned to the
gas flow (Figure 4-8). Seal around the Type S pitot tube, then record all
data (Figure 4-10) .
6. Repeat the preceding steps until three readings have been made for leg
A. Calibrate leg B in the same way. Calculate the pitot tube coefficient
by the equation
(Eq.4-1)
where ^p(s) = Type S pitot tube coefficient
= standard pitot tube coefficient
~ velocity head measured by the standard
pitot tube, cm fyO (in. fyO)
= velocity head measured by the Type S
pitot tube, cm /^O (in.
The deviation of each Cp/s\ from the average (Cp) is calculated by Cp(s) — Cp (ieg A
gj. Bj. Average deviation from the mean for leg A or B is calculated by the equation
(7 =
a must be < 0.01 for the test to be acceptable. | Cp^e A _ CP(side B)\ must also be
< 0.01 if the average of Cp(side A) and Cp(side B) is to be used.
4-13
-------
PITOT TUBE CALIBRATION
Pitot tube calibration number
Calibrated bv
Date.
A Side Calibration
Run No.
1
v>
.'•>
APstd
cm H20
(in. H20)
APs
cm H20
(in. H20)
^p(side A)
Cp(s)
Deviation
Cp(s)'Cp
-------
BAROMETER CALIBRATION
The field barometer should be calibrated against a laboratory mercury barometer
before each field use. If the field barometer can not be adjusted to read within 5.1
mm (0.2 in.) Hg of the laboratory barometer, it should be repaired or replaced.
The field barometer should be well-protected during travel.
CALIBRATION OF A STANDARDIZED DRY GAS METER
Reference volume meters are expensive for the average source sampling laboratory.
An inexpensive dry gas test meter calibrated against a reference volume meter is
accurate and convenient. This standardized test meter may then be used to
calibrate sampling console dry gas meters.
Calibration Equipment
1. Spirometer.
2. Dry gas test meter (0.1 cubic ft./meter revolution). This must be a test
meter to assure sufficient accuracy.
3. Oil manometer (0-2 inches H20).
4. Leak-free pump (lubricated fiber vane pump with appropriate oil traps
or diaphragm pump with gas pulse compensating baffle).
5. Needle valve.
6. Three-way valve.
7. Two dial thermometers capable of reading gas temperature ± 2°F.
Calibration Procedures
Possible equipment configurations for dry gas meter calibration are shown as
Figure 4-11.
4-15
-------
Valve
^e
Manometer
y
Centimeter rule
Counterweight
Outlet
thermometer
Inlet
thermometer
Rockwell dial face
#83 0.1. ft3/Rev
Dry gas test meter
Centimeter rule
Manometer
Counterweigh'
^r
Vacuum
pump
Outlet thermometer
Rockwell dial face
#83 O.I. ft3/Rev
Dry gas test meter
Figure 4-11. Dfy gas mteter calibration configurations.
The meter must be calibrated at several flow rates corresponding to pressure dif-
ferentials (AH) of 0.1, 0.5, 1.0, and 1.5 inches of water. The 1.5 AH may be
achieved by weighting the spirometer bell or using the pump; the other AH's can
be established without the pump. The pump could increase the gas temperature
4-16
-------
from the spirometer to the dry gas meter. If it does, gas volume must be corrected
for a temperature increase. Calibration of the meter without a pump in the system
eliminates the need for temperature corrections.
1. The calibration system should be assembled and thoroughly tested for
leaks at ^2 in H20. All leaks should be eliminated.
2. Level the spirometer and fill it with air. Allow the bell several minutes
to stabilize.
3. Completely open the spirometer outlet valve and establish a 0.1
in. H20 manometer reading into the dry gas meter using the gas-flow
needle valve. Close the spirometer outlet valve.
4. Read the spirometer meter stick settings. Read the dry gas meter dial
value.
5. Open the spirometer outlet valve, check manometer reading and allow
0.5 cubic feet of air to flow to the dry gas meter (5 revolutions of
0.1 ft.3/revolution dry gas meter dial).
6. Stop the air flow. Record the dry gas meter and spirometer settings on
the calibration form (Figure 4-12). Repeat the procedure for the other
AH values. Calculate and average the dry gas meter correction factors.
If the factor is outside the tolerance 1 ± 0.02, adjust the dry gas meter
internal sliding vanes and recalibrate.
If a pump is used in the calibration apparatus, it could heat the gas entering the
dry gas meter. This possibility requires that the dry gas meter volume be corrected
to conditions in the spirometer by the equation
(Eq.4-3)
Tamb
Vm(corr) ~ ^m
Pb Tm (avg)
When a pump is used, a three-way valve is employed to establish the flow rate
through the dry gas meter, using atmospheric air. The valve is switched to the
spirometer, and the dry gas meter is read.
CALIBRATION OF THE SOURCE SAMPLING NOMOGRAPH
A number of nomographs are available commercially. These instruments are used
to solve graphically the sampling nozzle sizing equation
4-17
-------
STANDARDIZED DRY GAS METER CALIBRATION
Name.
Date.
Ambient Temperature
Dry Gas Test Meter No.
Spirometer Displacement Factor
Barometric Pressure
Correction Factor (DGMCF)
Manometer
0.1 in. H20
0.5 in. H20
1.0 in. H20
1.5 in. H20
Spirometer
Volume (Vspir)
Final
Initial
Displacement
Volume (Vcr,:r)
F
I
D
F
I
D
F
I
D
Dry Gas Meter
Volume (Vm)
Final
Initial
Volume (Vm)
Tm
F
I
Vm
Tm
F
I
V
Tm
F
I
Vm
T
ter Volume *(Vspir)
cement (cm) X displacement factor (liters/cm) = Vspjr liters
Dry Gas Meter
Correction Factor
Average
DGMCF
Dry Gas Meter Correction Factor (DGMCF)
'spir
'm
= DGMCF
Average Dry Gas Test Meter Correction Factor Tolerance SV/DV = 1 ±0.02
*0.03431 cubic feet/liter
(liters)(. 03431 ft.3/liter) = ft.3
Figure 4-12. Form for standardized dry gas meter calibration.
4-18
-------
V 0.0358
T
TmCp(l-Bws)
where Dh = 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)
= average velocity head of stack gas (in. H2O)
and the isokinetic rate equation
(Eq.4-5) AH =
846.72 Dj AH@ Cp2
Pm
Today, programmable calculators are often being used to solve these equations.
Also, a number of plastic slide rules are currently available. These are
somewhat more accurate and more convenient to use than the traditional source
sampling nomograph.
If a nomograph is used, it should be thoroughly checked for scale accuracy and
alignment. Nomograph calibration forms (Figure 4-13) help in making these
checks. The traditional source sampling nomograph assumes that the Type S pi tot
tube has a Cp of .85. For Cp values different from .85, the C-factor obtained on
the nomograph must be adjusted by the method given in Form A (Figure 4-12).
The traditional source sampling nomograph also assumes that the molecular
weight of the stack gas is 29.1 Ib/lb-mole. For molecular weights appreciably dif-
ferent from this value, the C factor of the nomograph should be further adjusted
by the method given in Form B.
Traditional source sampling nomographs are usually made by fixing a decal on a
plastic board. Unfortunately, the scales printed on the decal frequently become
misaligned when the decal is applied to the board. Form C gives a procedure which
one can use to check the nomograph alignment. The calibration form gives the
values used to check the alignments. The check is accomplished by positioning the
marker line through the AH and Ap points given, and then tightening the pivot
point. The AH reading for each A/> value given is then read. If any AH readings
are off-scale or differ by more than 3% of the proper values, the scale is mis-
aligned. Nomographs which indicate such misalignment should be returned to the
manufacturer and replaced.
4-19
-------
SOURCE SAMPLING NOMOGRAPH CALIBRATION DATA
Form A. Correct the C-Factor obtained in normal operation of the nomograph for C *0.85 by:
. .__ .. (Pilot Tube Cp)2
(0.85)2
Nomograph
ID. No.
Nomograph
C-Factor
Pilot Cp
.9
Pm
29.92
29.92
29.92
Stack
TS°F
1000
300
:>oo
Ap
1.00
2.00
2.00
Nomograph
C-Factor
Calculated
Nozzle Dn
Nomo-
graph
AH
Calcu-
lated
AH
=()./:,; C =0.85; Bum = 0: M(1 = 29.()
Figure 4-13. Forms for source sampling nomograph calibration.
4-20
-------
Form D gives a procedure for checking the accuracy of the nomograph. Here the
true values obtained by using the equations given above are compared to the values
obtained by the nomograph manipulations. Calculated and nomograph values
should not differ by more than 5%. Nomographs showing greater error should be
returned to the manufacturer and replaced.
CALIBRATION OF THE PROBE NOZZLE DIAMETER
The probe nozzle should be made of 316 stainless steel or quartz with a sharp,
tapered leading edge. A taper angle of < 30° on the outside of the sampling noz-
zle will preserve a constant internal diameter. The nozzle should be a button-hook
or elbow design so that the nozzle opening is below the pilot tube sensing orifice.
This is necessary for isokinetic sampling. Alternate construction materials or nozzle
shapes must be approved by the administrator.
The sampling nozzle must be calibrated before use in a source experiment.
Calibration should be done in the laboratory and checked just prior to use in the
field. Inside/outside calipers are used to measure the interior nozzle diameter to
the nearest 0.025 mm (0.001 in.).
The calipers are inserted as close to the edge of the nozzle opening as possible;
readings are then taken on three separate diameters and recorded. Each reading
must agree within 0.1 mm (0.004 in.), or the nozzle must be reshaped. Any nozzle
that has been nieked, dented, or corroded must be reshaped and recalibrated. All
calibrated nozzles should be permanently identified.
4-21
-------
Chapter 5
The Source Test
A source sampling experiment provides data on source emissions parameters. The
ispkinetic 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
5-1
-------
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
5-2
-------
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 particulate 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 wjill 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 (See Calibra-
tion chapter, page 4-17).
The derivation of the isokinetic rate equation is given in Appendix C. The equa-
tion is:
f s
= 846.72 D* Atf@ Cp
L
r. r, f Tm Pr ~\
(Eq.5-1) AH= 846.72 D Atf@ Cp2 (l-B^ ty
L •"% 1s "m J
where Cp = pitot tube coefficient
Dn = nozzle diameter (in.)
AH '= pressure difference of orifice meter (in.
AH@ = orifice meter coefficient, AH for 0. 75 cfm at
STP= 0.9244/1^2 ftn_ HZQ)
Ms = apparent stack gas molecular weight
= Md(l-Bw) + 18Bw (Ib/lb-mole)
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. H2O)
Tm = absolute meter temperature = °R= °F+ 460°
isokinetic AH=KAp
K = Reduced terms in the isokinetic equation.
5-3
-------
Figure 5-1. Planning and performing a stack test.
EACH STACK TEST
SHOULD BE CONSIDERED
AN ORIGINAL SCIENTIFIC
EXPERIMENT
DETERMINE NECESSITY OF A SOURCE TEST
•Decide on data required
•Determine that source test will give this data
•Analyze cost
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 for completion
•Note shift changes
•Determine accessibility of sampling site
•Evaluate safety
•Determine port locations and application to
Methods 1 and 2 (12/23/71 Federal Register)
•Locate electrical power supply to site
•Locate restrootns and food at plant
•Drawings, photographs, or blueprints of sampling site
•Evaluate applicability of sampling a
experiment design
•Note any special equipment needed
ipproach from
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. HgO vapor
b. Temperature at
source
•Study analytical pro-
cedures used for
processing test samples
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
CALIBRATE EQUIPMENT
•DGM
•Determine console AH@
•Nozzles
•Thermometers and
thermocouples
•Pressure gages
•Orsat
•Pitot tube and probe
•Nomographs
FINALIZE TEST PLANS
•Incorporate presurvey into experiment design
•Submit experiment design for ap-
proval by Industry and Regulatory Agency
•Set test dates and duration
1
PREPARE EQUIPMENT FOR TEST
•Assemble and confirm operation
•Prepare for shipping
•Include spare parts and reserve equipment
1
CONFIRM TRAVEL AND SAMPLE TEAM ACCOM-
MODATIONS AT SITE
I
PREPARE FILTERS AND
REAGENTS
•Mark filters with insoluble
ink
•Desiccate to constant
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
CONFIRM TEST DATE AND PROCESS OPERATION
•Final step before travel arriving at site
SAMPLING FOR PARTICIPATE EMISSIONS
•Carry equipment to sampling site
• Locate electrical connections
•Assemble equipment
PRELIMINARY GAS VELOCITY TRAVERSE
•Attach thermocouple or thermometer to pitot
probe assembly
•Calculate sample points from guidelines outlined in
Method J and 2 of Federal Register
•Mark pitot probe
•Traverse duct for velocity profile
•Record Ap's and temperature
•Record duct static pressure
T
DETERMINE APPROX-
IMATE MOLECULAR
WEIGHT OF STACK GAS
USING FYRITE AND
NOMOGRAPHS
APPROXIMATE HoO
VAPOR CONTENTOF
STACK GAS
5-4
-------
RECORD ALL INFORMA.
TION ON DATA SHEETS
•Sample case number
•Meter console number
•Probe length
•Barometric pressure
•Nozzle diameter
•C factor-
•Assumed HgO
•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
FYRTTE READINGS
ACROSS DUCT)
ANALYZE STACK GAS FOR
CONSTITUENT GASES
•Determine molecular
weight
•CO, and O,
concentration for F-factor
calculations
PREPARE OTHER TRAINS
FOR REMAINING
SAMPLING
REPACK EQUIPMENT
AFTER SAMPLING IS
COMPLETED
t
USE NOMOGRAPH OR CALCULATOR TO SIZE
NOZZLE AND DETERMINE C FACTOR
•Adjust tor molecular weight and pilot tube C
•Set K pivot point on nomograph v
LEAK TEST COMPLETELY ASSEMBLED
SAMPLING TRAIN @15" Hg VACUUM AND
MAXIMUM LEAK RATE OF 0.02 CFM
NOTIFY ALL CONCERNED THAT TEST IS ABOUT
TO START
I CONFIRM FROCESS OPERATING PARAMETERS I
• »
START SOURCE TEST
•Record start time - military base
•Record gas velocity
•Determine AH desired from nomograph
•Start 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
•Clean 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 and label all 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 (process 9 test)
•Attach descriptions of testing and analytical methods
•Signatures of analytical and test personnel
SEND REPORT WITHIN MAXIMUM TIME
TO INTERESTED PARTIES
5-5
-------
Figure 5-2. Source test outline.
CALIBRATE EQUIPMENT
•Nozzles
•DGM
•Orifice meter
•Meter console
•Pilot tubes
•Nomograph
| ASSEMBLE SAMPLING TRAIN
I
LEAK TEST
•Pitot lines
•Meter console
•Sampling train @ 15" Hg.
| SET UP NOMOGRAPH OR CALCULATOR
•Mark dry and desiccate
filters to constant weight
•Assemble in filters and seal
until ready to use
ESTIMATE CO2
CONCENTRATION USING
FYRITE
1
CALCULATE SAMPLE POINT USING METHOD 1
1
DO PRELIMINARY TEMPERATURE AND
VELOCITY TRAVERSE
1
1
ESTIMATE Hj<
USING WET B
BULB
1
PREPARE TO TAKE
INTEGRATED SAMPLE OF
FLUE GAS DURING EN-
TIRE DURATION OF TEST
ANALYZE USING ORSAT
FILL OUT DATA SHEET
•Date
•Time
•DGM Reading
•Test time at each point
MONITOR AT EACH TEST POINT
•DGM—On time
•Ap
•Appropriate AH
•Stack temperature
•Sample case temperature
•Impinger temperature
STOP TEST AND RECORD
•Final DGM
•Stop time
•Notes 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
•HzO
•Silica Gel
CALCULATE
•Moisture content of gas
•Molecular weight of gas (dry 8c wet)
•Average gas velocity
•% isokinetic
•Pollutant mass rate
(concentration and ratio of areas)
WRITE REPORT
5-6
-------
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)
/
1 70.
Dn=\
H ]/
Tm Cp(l-Bws)
where 0^ = nozzle diameter (in.)
Qjn = volumetric flow rate through meter
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)
> = average velocity head of stack gas (in.
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 follow-
ing the procedure given in the calibration chapter, page 4-1. 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
5-7
-------
console pump. This allows the pump to lubricate itself and to warm up (this is
especially important in cold weather). Leak test the pilot tubes and lines during
this warm up.
The pi tot tube impact pressure leg is leak tested by applying a positive pressure.
Blow into the impact opening until > 7.6 cm (3 inches) H20 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 pilot tube is leak tested in a
similar way by drawing a negalive pressure > 7.6 cm H20. Correcl any leaks.
The sampling irain is leak lesled when il has reached operaling lemperalure.
Turn off ihe console pump; connecl the umbilical vacuum line. Wilh ihe coarse
conlrol value complelely off, lurn ihe fine adjuslmenl (bypass) valve completely
counterclockwise. Plug ihe nozzle inlel and lurn on ihe console pump. Slowly lurn
the coarse adjuslmenl valve fully open. Gradually lurn ihe fine adjuslmenl valve
clockwise unlil 380 mm (15 inches) Hg vacuum appears on ihe vacuum gage. If
this vacuum is exceeded, do not lurn ihe fine adjuslmenl valve back
counlerclockwise; proceed wilh ihe leak lesl al ihe vacuum indicaled or slowly
release ihe nozzle plug and reslarl ihe leak lesl. At ihe desired vacuum observe ihe
dry gas meler poinler. Using a slopwalch, lime ihe leak rale for al leasl 60
seconds. The maximum allowable leak is 0.00057 mVmin. (0.02 cfm). Having
deiermined the leak rale, slowly release ihe nozzle plug lo bleed air inlo the Irain;
when the vacuum falls below 130 mm(5 inches) Hg, turn ihe coarse adjuslmenl
valve complelely off. If ihe leak tesl is unacceptable, trace all sections of the
sampling train from ihe filler holder inlel back, (i.e., leak lesl from the filler inlel,
then the first impinger, elc.) unlil ihe leak is found. Correcl ihe leak and relesl.
Leak lesl al the highest vacuum reached during ihe lesl after ihe completing ihe
sampling procedure. Tesling for leaks should also be done any lime'ihe train is
serviced (i.e., filter holder change). Record all dry gas meler readings and leak
rales for each leak lesl.
Train Operation
When ihe leak tests are compleied, the sampling console should be prepared for
sampling. The sampling console differenlial pressure gages for ihe pilol lubes and
orifice meler should be checked. Zero and level ihe gages as required. If ihe con-
sole does not use oil manometers, ihe gages musl agree wilh an oil manomeler
wilhin 5 percenl for al leasl 3 A^» readings taken in ihe slack. This check should be
done before lesiing. Oil manometers should be periodically leveled and re-zeroed
during the test if they are used in the console.
The console operator should then determine the source variables used in solving
the isokinetic rate equation. The isokinetic AH may be deiermined by using a
nomograph, an electronic calculalor, or a source sampling slide rule. The variables
that need to be determined are: stack gas moisture content, average gas velocity
pressure (&p), stack gas temperature, and estimated average console dry gas meter
temperature. The stack gas moisture can be determined by Reference Method 4
5-8
-------
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 HNOs 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.
5-9
-------
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 mVmin (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
5-10
-------
Probe Sheath and Pilot 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 pilot tubes for
damage and proper construction details (see pilot tube calibration seclion). Pilol
tubes should be cleaned, checked for cracks or breaks, and securely fastened to the
probe sheath to prevent accidental misalignment in ihe slack. All pilot lubes 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 tighl
seal. If a rubber o-ring gaskel is used (stack temperalures < 350 °F) il 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 ihe probe in ihe following manner lo 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 pilol lube orifice
openings;
5. Screw ihe union on finger lighl;
6. Use probe wrenches lo lighlen ihe union. If loo much lighlening is done
here, ihe end of ihe glass liner will break.
Glass Liner-Heating Element
The glass liner should be ihoroughly cleaned wilh a probe brush, acelone, and
distilled H2O. If il will nol come clean in ihis manner, il should be cleaned wilh
dilule HC1 or replaced. The glass liner-heating element in many sampling probes
can nol be separated, making ihorough cleaning difficull. An easily separated
liner-healer is a greal advanlage.
The heating element should be checked for good eleclrical insulation; ihe insula-
tion on a frequenlly used probe liner heating element will eventually be worn or
burned away. This can expose frayed wires, which may short against ihe probe
sheath. These hazards can be avoided with careful inspections and repair. After
ihorough inspeclion, check ihe healing elemenl in ihe reassembled probe. This
procedure is helpful in finding problems before arrival al ihe sampling sile. Allen-
lion should be given lo ihe function of the electrical syslem and wrappings around
the glass liner; these wraps help prevent eleclrical shorls againsl ihe probe shealh
while minimizing glass liner flexing lhal can cause a liner break or eleclrical short.
5-11
-------
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.
5-12
-------
Figure 5-3. Cleaning the sample train.
Toting completed
Perform final leak check on sampling train
with vacuum £ lest vacuum. Leak rate must
be S O.OZ cfm.
Inspect sample and record observations
_L
_L
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)
Cap noiilc to prevent
paniculate loss.
1. Clean nozzle exterior
first.
2. Be sure cap will not
melt to nozzle.
S. Be sure paniculate
will not nick to cap
Separate
probe and filter
i
&IL
probe
end
1
1
— i
Cap filter
inlet and
outlet
1
Remove impinger HgO
[
Take volume then store
in marked container
1
Additional analysis
optional
Store silica gel
in the same container
it was originally
weighed in
Weigh to nearest 0.5 gm '
Clean probe exterior
Blowout
pilot tubes
Disassemble
filter
Wash excess
dust off probe
sheath and
nozzle
Carefully remove nozzle
and probe end caps
Do not allow pani-
culate to be lost
Organic-Inorganic
extraction
Filter mat placed in
clean, tared
weighing dish
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
stainlea steel or teflon
handle
1
Brush entire length of
probe with acetone £ 3
times into marked
container or clean,
tared beaker
1
Remove nozzle and inspect it
and probe liner
1
| Weigh and record
|
| Desiccate 6 hrs.
1
Weigh and record.
Continue to constant weight —
weights differ S 0.5 mg
Clean probe liner again until no Clean nozzle by rinsing with acetone
sign of paniculate* can be seen in the 1. Brush interior from blunt back side only.
acetone or on the glass 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 filter
5-13
-------
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 paniculate 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.
5-14
-------
Impinger H2O
Record total volume
Add to 500 ml separatory funnel
Add 50 ml anhydrous diethyl ether Et£O
Shake 3 minutes venting ether fumes periodically
Let stand for separation of layers
i
H2O 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
H2O to tared beaker CHCls + 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.
5-15
-------
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.
5-16
-------
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.
5-17
-------
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.
5-18
-------
METHOD 5—SOURCE TEST DATA SHEETS
Preliminary Survey—Source Sampling Site
Date Survey investigator
Plant name City State_
Previous test(s) by: Reports available
Plant contacts Title Phone_
Title Phone,
Title Phone_
Complete directions to plant from point of origin
Local accommodations: nearest motel miles
Restaurants
Nearest hospital Phone
Rental cars and vans available
Plant Operation and Process Description
Description of process
Description of control equipment.
Schematic Drawing of Process Operation (Note location of sampling)
Sites and control equipment:
Sampling sites Anticipated constituents of stack gas
1
2
3
4 .
5
5-19
-------
Process fuel type(s)
Process raw material(s)
Process production rate(s)
Samples to be taken of:
Feed rate
Consumption rate(s).
Plant operation: Continuous
Shift changes and breaks
Batch.
Plant facilities: Entrance requirements
First aid Safety equipment
Laboratory
Reagents
Food
Restrooms
Compressed air source
Equipment available
Ice
Sampling Site and Stack Information
Sampling
site
Type
Pollutant
emissions
Duct
dimen-
sions
Duct con-
struction
material
No. of
sample
ports
Port
dimen-
sion
Diameters
straight
run to
ports
Duct gas
temp.
°F
Duct gas
velocity
ft./sec.
Average
Apin.
HgO in
duct
%
Ap
in gas
Stack
pressure
in. Hg.
Sketch of duct to be sampled with port locations and all dimensions
5-20
-------
Sketch of sampling site including all dimensions
Access to work area
Work area (locate electrical outlets)
Electrical outlets available
1. Voltage
2. Extension cords needed,.
3. Adapters
_ft.
Recommended modifications to sampling site.
Sampling method suggested :
Equipment needed: Sample probe length
Glassware Sample case: Horizontal traverse.
Nozzles.
No. of needed sample cases
Special equipment:
Meter consoles
Probes
Vertical.
Filter assemblies
Reagents needed.
Safety at Site
Condition
descrip-
tion
Good
Adequate
Poor
Intolerable
Sampling
site(s)
general
Ladders
Scaffolds
Platforms
Lighting
Ventila-
tion
Chemical
hazard
protection
Warning
system
5-21
-------
Personnel Safety Equipment
Item
Needed
at site
Avail-
able at
plant
Must be
brought
by
sample
team
Safety
glasses
Full
face
shields
Hard
hats
Safety
shoes
Safety
belts
Hearing
protec-
tion
Respiratory equipment
Puri-
fying
type
Self
con-
tained
Air
supplied
Fire
extin-
guishers
Chemi-
cal pro-
tection
gar-
ments
Heat
protect-
ing gar-
ments
Asbestos
aprons,
gloves
Description of additional safety equipment recommended:
Comments:
5-22
-------
Method 1—Sample and Velocity Traverses for Stationary Sources
Sample Site Selection and Minimum Number of Traverse Points
Location
Date
Plant
Sampling location
Sample team operator(s) ^_____
Sketch of stack geometry (including distances from sample site to any disturbances)
Interior duct cross-section dimension
Sampling port diameter
Sampling port nipple length.
Stack cross-sectional area
.ft
Jn.
Sampling site: diameter downstream of disturbance
Minimum number of sampling points
Total test time
Comments:
Diameters upstream
Individual point sample time
Sketch of Stack Cross-Section Showing Sample Ports and all Dimensions
Sample point
number
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Circular stack
% diameter
Distance from
sample port
opening in.
5-23
-------
Gas Velocity Traverse Data
Plant
Date.
Plant location
Sampling location
Operator(s)
Dry molecular weight of stack gas Ib/mole. Moisture content %H20
Pilot tube Cp Barometric pressure Stack static pressure
Stack cross-sectional area (As)
ft 2
Sample
point
no.
1
2
3
4
5
6
7
8
9
10
11
12
Distance
into stack
from stack
wall
Port A
Ap
H20
in.
fa
TS°F
Port B
Ap
H20
in.
fa
TS°F
Port C
Ap
H20
in.
fa
TS«F
1
Port D
AP
H20
in.
fa
TS°F
Average TS°R(TS°R)
Average Ap
[Sum of TS°F at each sample point"!
Total no. sample points J
—r [Sum of the ^Ap at each sample point) _
"Total no. samnle nnints -I
+ 460 =.
Total no. sample points
in. H20
Average stack gas velocity (vs) =
ft /sec
where Kp = 85.49 ft.
ft./sec. |/
Ib/lb mole (in. Hg )
(°R) (in. H2O
Average actual stack gas volumetric flow rate
i = (vs)(As)X 3600 sec /hr =_
.ACFH
Average dry stack gas volumetric flow rate at standard conditions
(Qs)-(3600 sec /hr )(l-Bws)(vs )(AS)
Tstd
Pstd
DSCFH
5-24
-------
Orsat Field Data
Orsat identification no..
Checked by
Plant location
Operator(s)
Sampling location
Moisture content of stack gas (Bws)_
Fuel feed rate
Process production rate
Comments:
Date reagents added.
Sampling date
Average fyrite CO2
Fuel used.
Combustion source description_
Steam production rate
Test no.
Sample time
Start
Stop
Analysis
time
Burette readings
CO2
02
CO
Component
CO2
O2 - CO2
CO-O2
100-CO = N2
Mole fractions % composition /1 00
Dry molecular weight of stack gas (M^) = £MXBX
Md= .44 ( %C02)+ .32 ( %02)+ .28 ( %CO)+ .28 ( %N2)= g/g-mole
Wet molecular weight of stack gas (Ms) = Md(l-Bws) + 18gm/m(Bws)
Ms = ( g/g-mole (1- ) +18 g/g-mole ( ) = g/g-mole
%02-0.5(%CO)
% Excess air in the duct (%EA) = —
=r _ (— %o2>- ---------- _ |X100=
L(0.264)( _ %N2)-( _ %02) + 0.5( _ %CO)J
%EA
/0
264)(%N2)-(%02) + 0.5(%CO)
-0.5( %CO) I
xlOO
5-25
-------
Method 4—Reference Method for Determining Moisture Content
of a Stack Gas
Date
Plant
Location
Sampling location
Operator
Run no
Schematic of Stack Cross-Section
Ambient temperature
Barometric pressure
Probe length
Traverse
point #
Sample
0 + n^.
Velocity
head = Ap
in. H20
Rota-
meter
setting
Dry gas
meter
reading
Average inlet-
outlet gas sample
temp, at DCM
Gas temp.
at last
impinger
Sample Train No.
Final
Initial
Diff.
Impinger
Volume
(WC) ml
Silica Gel (SG) gm
(1 gmH20 =
1 ml HgO)
Standard ft** H20 collected in the impinger =
VWC(std) = WCH2OmlX 0.04707(ft3/ml) = —i
Standard ft* H20 collected in silica gel =
std) = SGH2Omlx0.04715(ftVg) = —ft3
Volume metered at standard conditions =
Vm(stdrVrn(l7.64)£lIL = — &
\ ' lm
Bws~
Vwc(std) + Vwsg(std)
Vwc(std) + Vwsg(std) + Vm(std)
^ HoO = B xlOO =
5-26
-------
Particulate Field Data
Very Important—Fill in all Blanks
Plant
Run no.
Location
Date
Test start time .
Stop time
Operator
Sample box no.
Meter box no.
Nomograph ID no.
Orsat no. Date rebuilt
Fyrite no. Date rebuilt
Pm, in. Hg _
Ps, in. Hg
BWS (assumed).
d ~~
lnv
°R
Dn calculated (in.)
Dn, used (in.)
Ambient temp., °F
Bar. pressure, in. Hg
Heater box setting, °F
Probe heater setting, °F
Average AH
Apavg,in. H20
Leak rate® 15 in. Hg Pre-t
Post-test.
Point
Clock
time
(min)
Dry
gas
meter
CF
Pitot
in H2O
Ap
Orifice AH
in H2O
Desired
Actual
Dry gas
temp. °F
Inlet
Outlet
Pump
vacuum
in. Hg
gauge
Box
temp.
°F
Impin-
ger
temp.
OF
Stack
press.
in. Hg
Stack
temp.
°F
Fyrite
%CO2
Comments:
Test observers:
continued
-------
Point
Clock
time
(min)
Dry
gas
meter
CF
Pitot
in H2O
Ap
Orifice AH
in H2O
Desired
Actual
Dry gas
temp. °F
Inlet
Outlet
Pump
vacuum
in. Hg
gauge
Box
temp.
OF
Impin-
ger
temp.
°F
Stack
press.
in. Hg
Stack
temp.
°F
Fyrite
%CO2
ISO
00
Comments:
Test observers:
continued
-------
Laboratory Analysis Data Particulate Source Sample
Analysis date(s)
Plant sampled
Sampling location
Sample run no.
Sample labels: H£() .
Impinges rinse
Analysis performed.
Reference method
Comments:
Analytical chemist.
Location
Silica gel
_ Dry paniculate.
_ Sampling date(s)_
Sampling case no. _
Filter
Probe.
Other.
Analytical sample temp.
Moisture Data
Final volume HoO in impingers
Initial volume HoO in impingers
Volume HoO condensed
Final weight silica gel
Initial weight silica gel
Particulate Data
CH3-CH2-O-CH2-CH3/CHCL3 extract
Flask no.
Final weight
Initial weight
Organic fraction
Extracted HoO Flask No.
Final weight
Initial weight
Inorganic fraction
Filter Flast No.
Final weight ,
Initial weight
Filter and particnlates
Filter no. Tare weight
Particulates
Dry particulates and probe_
Front half particulates
Total Moisture
ml H20 Condensed ml
ml
ml HoO Ahsorhed ml
gm HoO Total ml
_£in
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
Total Particulate Sampled
Organic fraction mg
Inorganic fraction mg
Front half participates mg
Total Particulates
Run No.
mg
5-29
-------
Chapter 6
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)
W
i
Deviation from Average Cp (Leg A or B of Type S tube)
(Eq. 6-2) Deviation = Cp(std) - Cp
Average deviation from the mean 5 (Leg A or B)
(Eq. 6-3) * lCp(s)~Cp(AorB)\
0 -L* o
1 3
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 *)
Test Meter Correction Factor
Spirometer Standard ft *
(Eq. 6-5) = Test meter correction factor
Test meter ft 3
6-1
-------
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 (Qj^) in cubic feet per minute
(Eq. 6-7) Qm = [Test meter (VJ)- Test Meter V{] X [Test meter correction factor]
l/j
Proportionality Factor (Km)
(Eq. 6-8) Km:
Orifice meter A//@ Flow Rate
0 9244
(Eq. 6-9) 1. English units Af/@ = —-—=-
where A//@ = 0.75 cfm at 68°F and 29.92 m. //g
0.3306
(Eq. 6-9) 2- vt* 2
where AH@ = 0.021 m^/ram a* 760 mm //g and 20°C
Sampling Meter Console Calibration
Ratio of the accuracy of Console Gas Meter Calibration Test Meter (7).
Tolerance 1±0.02
VT Tm Pb
(Eq. 6-10) 7= I
PI,
13.(
Meter Console Orifice Meter Calibration
(Eq. 6-11) L
m
where A: = 0.0317 English units
= 0.0012 metric units
0 9244
(Eq. 6-12) 2 . A//@ = ^2±
'
Lm
6-2
-------
Source Sampling Nomograph Calibration
Isokinetic AH Equation
Isokinetic AH= 846.72
6-13) | "* r Ms Ts Pm
Sampling Nozzle Equation
1 /
Y
0.0358 P ,TM
Adjusted C-Factor (Cp)
r
I P
(Eq. 6-15) C factor adjusted = cfactor I Q.85
Adjusted C-Factor
1-^+181^/29
(Eq. 6-15) C-factor adjusted = Cfactor \ -Bws+\8Bws/Md
SOURCE SAMPLING CALCULATIONS
Method 1—Site Selection
Equal Area Equation (circular ducts)
P= >
(Eq. 6-16) f "" I * \ 2n
Equivalent Diameter for a Rectangular Duct
2(length) (width)
(Eq. 6-17) E length + width
Method 2—Gas Velocity and Volumetric Flow Rate
Average Stack Gas Velocity
(Eq. 6-18) vs = KpCp
Average Dry Stack Gas Volumetric Flow Rate at Standard Conditions (Q.j)
(Eq. 6-19) Qs = 3600 (1 - Bws)vs As I ~^—
n \pstd\
6-3
-------
Method 3 — Orsat Analysis
Stack Gas Dry Molecular Weight
(Eq. 6-20) Md = ZMXBX = QA4(%CO2) + 0.32(%02) + Q.28(%N2 + %CO)
Stack Gas Wet Molecular Weight
(Eq. 6-21) Ms = Md(l - Bws) + 18 Bws
Percent Excess Air (%EA)
-0.05(%CO)
(Eq 6-22) %EA= - - - (—-^- - XI 00
V q 0.264 (%N2) - (%02) +
Method 4 — Reference Moisture Content of a Stack Gas
Volume Water Vapor Condensed at Standard Conditions (Vwc)
(ml H2O)ow R
(Eq. 6-23) Vwc = I - 2 JQW = Kl (Vf
pstd Mw J
where Kj =0.001333 m? /ml for metric units
= 0. 04707 ft.3 /ml for English units
Silica Gel
(Eq. 6-24) K2 = (Wf~ ™i) = Vw ^
where #2 = 0.001335 m^/gmfor metric units
= 0. 04715 ft.* /gm for English units
Gas Volume at Standard Conditions
(Eq.6-25) Vm(std)=VmY,
Moisture Content
(Eq. 6-26)
SG
wc W m(std)
Method 5 — Particulate Emissions Testing
Dry Gas Volume Metered at Standard Conditions
Leak Rate Adjustment
N
(Eq. 6-27) Vm=[Vm-(L1-La)e-L (L{- L^- (Lp
2 — ^
6-4
-------
Standard Dry Volume at Sampling Meter
(Eq. 6-28) V
Isokinetic Variation
Raw Data
100 7} [K3 Vic + (Vm /Tm) (Pb + AH/13.6;;
(Eq. 6-29) %/ =
60
where Jfr = 0.008454 m™ "8
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 AH readings.
Intermediate Data
~r ,™ Ts vm(std) pstd v Ts vm(std)
(Eq. 6-30) > %/=100 - (— '- - = K4 [ '
Tstd % & An Ps 60(1 -Bw) P* vs An^ Bws)
where K. 4 = 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^
(Eq. 6-31)
V™(std)
where K.$ — 0.03203 g/meq for metric units
= 7.061 XlO~5 lb/meq for English units
Sulfuric acid mist (including sulfur trioxide) concentration
^solution^
n, ,,ox
(Eq. 6-32) CH2S04=K2
Vm(std)
6-5
-------
where
Isokinetic Variation
Raw Data
(Eq. 6-33)
where
= 0.04904 g/meqfor metric units
= 1.08 X 10-4 lb/meqfor English units
~
= 0.003464 mmHg-m3/m/- °K
= 0.002676 in.Hg-ffi/ml- °R
Concentration Correction Equations
Concentration Correction to 12%
(Eq. 6-34)
Concentration Correction to 50% Excess Air Concentration
(Eq. 6-3
Correction to 50% Excess Air Using Raw Orsat Data
(Eq. 6-36)
1-
(1.5)(%02)-(0.133)(%N2)-0.75(%CQ)
21
F-Factor Equations
Fc Factor _
(Eq. 6-37) ' = *CM%C02)
Used when measuring cs and CO2 on a wet or dry basis.
Fd Factor
When measuring O%d and cs on a
(Eq. 6-38)
20.9
When measuring O^d and c s on a wet basis
(Eq. 6-39)
20.9
Jws
6-6
-------
Fw Factor
• When measuring c$ and 0% on a wet basis
• Bwa = moisture content of ambient air
• Cannot be used after a wet scrubber
20.9
20.9(1 -Bwa)-%02w
(Eq. 6-40) E = Ft
F0 Factor
1. Miscellaneous factor for checking Orsat data
20.9 Fw 20.9 -O?j (O2 and COz measured]
(Eq. 6-41) F0= — = — \ on dry basis
° 100 Fc %C02d \ y '
Opacity Equations
% Opacity
(Eq. 6-42) % Opacity =100—% Transmittance
Optical Density
(Eq. 6-43) Optical Density = log\Q
(Eq. 6-44) Optical Density = log\Q
\ > 1
1 — Opacity J
Transmittance]
Transmittance
(Eq. 6-45) Transmittance = e
Plume Opacity Correction
(Eq. 6-46) l°g(l ~ °l) = (-^1/^2) l°S(l ~ °z)
6-7
-------
Chapter 7
Report Writing
The report of a source sampling test presents a record of the experimental pro-
cedure and the test results; it is a written statement describing a scientific experi-
ment and should follow the basic rules of accepted form. The report must state the
objectives of the experiment, the procedures used to accomplish these objectives,
results of the experiment, and conclusions that may be drawn from these results.
The information should be presented in a clear, concise manner. The report must
document all aspects of the testing for it may be used in litigation. A suggested for-
mat for the report is given in this section with a brief explanation of each topic.
An outline of the format follows these explanations.
PRESENTATION
The test report should be presented as a professional document. It should be
bound in an appropriate cover and contain a cover page giving the title of the
report, the identity of the organization for which the test was performed, and the
test team as well as, the location and dates of the testing. Following the cover page
should be a signature page with a statement of the careful performance of the test
and preparation of results signed by all test participants, laboratory personnel, and
supervisors. This is essential for documentation and legal purposes. A table of con-
tents then follows, and includes all topic listings and appendixes with page
numbers. An accurate table of contents is always appreciated by those reading the
report.
INTRODUCTION
The report introduction will briefly define the purpose of the test. It will include a
short description of the basic sampling method and of the process and control
devices used and give testing location and date along with the names of the test
team personnel. The introduction should also identify industrial or regulatory
agency personnel present on site during the tests.
SUMMARY OF RESULTS
The summary of test results is extremely important. This is usually the first item of
the report read; often it is the only section that anyone reads and it is presented as
the first item in the report for this reason. The summary of results is a concise
statement of test methods and results. The sampling equipment is described as are
the test methods employed. Standard methods are referenced to State or Federal
guidelines, with approved method changes referenced to sources used or regulatory
agency giving approval. The source emission rate determined by the test is
expressed in appropriate English and metric units. Comments concerning the pro-
7-1
-------
cess rate and continuity during the test are also given. State and/or Federal
regulatory emission rates are stated. The test summary should then give a conclu-
sion about the test program and the results.
PROCESS DESCRIPTION
A full description of the process is essential. Include the process description with
any charts of process monitoring equipment (fuel feed rate, steam flow, materials
produced, etc.) and samples of calculations used for determining production rate.
Provide a flow diagram of the entire process with all pertinent information
regarding production and control equipment. A full accounting of process
operating conditions during the test should be included with these charts and
diagrams. Specific attention must be given to the control equipment. State the
manufacturer's name and operating specification with notes on the operation of the
device during the test.
TESTING METHODOLOGY
A detailed description of the sampling scheme is given in this section. Drawings,
photographs, or blueprints of the stack or duct and sampling ports, including all
dimensions actually taken by the test team, are required. These must be accom-
panied by a diagram showing the location of the sampling points within the duct
and all important dimensions. Descriptions of the sampling and analytical pro-
cedures are required. The methods and specific equipment used should be stated
and referenced. All modifications to standard procedures must be noted. Justifica-
tion for these changes in addition to authorized approval from regulatory agencies
or industrial personnel is necessary.
RESULTS
The results portion of the report should allow easy access and review of sum-
marized data. Present raw field and laboratory data in summary charts and tables
with easily understood examples of the calculations made. Listing the results of
these calculations in easy-to-read tables increases the value of this section.
APPENDIX
The appendix should include the following items:
• Test Log —record of events at the site.
• Raw field data sheets (or signed copies).
• Laboratory report including raw data, tables, and calibration graphs.
• Testing equipment listing:
1. Design and manufacture;
2. Calibration procedures and data sheets;
3. Serial numbers of equipment used in test.
• A copy of Federal Register or other reference procedure outline.
• A copy of applicable statutes and regulations concerning the testing.
7-2
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QUICK REFERENCE OUTLINE FOR REPORT WRITING
I. Presentation of report
A. Bind in suitable cover
B. Cover page
1. Report title
2. Organization requesting test
3. Organization performing test
4. Location and dates of test
C. Table of contents
II. Report
A. Introduction
1. Test objectives
2. Brief process and control equipment description
3. Test dates and personnel
a. Samplers
b. Observers
B. Summary of results
1. Brief test method identification
2. Regulatory agency approval of method
3. Comments on process operation
4. Emission rate determined by the test
5. Emission rate limit given by law
C. Process description
1. Describe process
2. Describe control equipment
3. Flow diagram of entire process
4. Charts and calculations of process production rates
D. Testing methodology
1. Sampling scheme with drawing and dimensions of site and sample
points
2. Description of sampling method
3. Description of analytical method
4. Modifications to methods and approved justification
E. Results
1. Summary of data
2. Charts and tables
3. Example calculations
F. Appendix
7-3
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Chapter 8
Error Analysis
Role of the Observer
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 in-
correctly to denote what properly should be called a "discrepancy"):
(I) To denote the difference between a 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 10^ 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.
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
textbook. 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 handbook values.
*Adapted from Y. Beers, Theory of Errors, Addison-Wesley, Reading, Mass, (1958) pp.1-6.
8-1
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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. Sometimes
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.
Corrections: Determinate systematic errors and some determinate random errors
may be removed by application of suitable corrections. For example, the
measurements that were in error due to a kink in a steel tape may bt eli ninated by
comparing the tape with a standard and subtracting the difference from all the
measured 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
temperature 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 any of the individual ones.
If some of the individual values are 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 specialized 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 experimen-
tal 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.
Random Errors:
(1) Errors of judgment. Most instruments require an estimate of the fraction 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 elec-
trical instruments, the pickup of spurious signals from nearby rotating elec-
trical machinery or other apparatus.
(4) Definition. Even if the measuring process were perfect, repeated
measurements of the same quantity might still fail to agree because that
quantity might not be precisely defined. For example, the "length" of a rec-
tangular 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 depending 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 calculating
the results of an experiment (such as slide rules, logarithm tables, adding
machines) should have errors small enough to be completely negligible in
comparison with the natural errors of the experiment. Thus if the data are
8-3
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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 tables or some other more
accurate means of calculation should be used.
(3) 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 the experiment should be discon-
tinued until the source of the disturbance is removed.
THE ROLE OF THE AGENCY OBSERVER*
Introduction
Air pollution control agency personnel who may not be directly involved in the
compliance source sampling process are often called upon to evaluate source tests
performed by environmental consultants or companies. Since emission testing
requires that industry, at their own expense, contact highly skilled source test
teams, the source test observer should be prepared to ensure that proper pro-
cedures are followed and that representative data is obtained.
The main purpose for the agency's observation of the compliance test is to deter-
mine that the test data is representative. There are other valid reasons to observe
the test, such as establishing baseline conditions for future inspections, but the
major emphasis is on the evaluation of the acceptability of the initial compliance
test.
The seven steps an agency generally uses for establishing the compliance of a
source with the agency's regulatory requirements are as follows:
1. Familiarize — the agency establishes contact with the source and becomes
familiar with operations, emissions, and applicable regulations.
2. Schedule source test— this may be part of a compliance schedule of Federal
Standard of Performance for Stationary Source Enforcement (NSPS).
3. Establish methodology— testing requirements should be established and a
testing plan developed by the agency.
4. Final plan and test procedure develoment —a presurvey should be conducted
by a member of the testing team. A pretest meeting between the agency,
source rep* ^sentative, and test team representative should be held to develop
the final test plan.
* Adapted from W. G. DeWees, Supplemental Training Material' for Technical Workshop on
Evaluating Performance Tests, DSSE, EPA. PEDCo- Environmental Specialists
8-4
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5. Actual compliance tests— observation of the facility operations and testing
methodology.
6. Review of test data— determination of compliance and official notification.
7. Continuing enforcement of compliance— followup inspections using data
generated from source tests as baseline for comparison purposes.
There are five areas where problems might develop in obtaining a sample
representative of the source emissions. If a question arises as to the integrity of any
one of these areas, the compliance test may be considered nonrepresentative. These
five areas are:
• The process and control equipment must be operated in such a manner as to
produce representative atmospheric emissions.
• The sample port and point locations must be representative of the atmospheric
emissions.
• The sample collected in the sample train must be representative of the sample
points.
• The sample recovered and analyzed must be representative of the sample
collected in the sample train.
• The reported sample results must be representative of the recovered and
analyzed sample.
The source test to be monitored by the observer, then, is developed and con-
ducted by the source test team and observer in four major phases: (a) preparing
and planning, (b) conducting the test, (c) recovering, transporting, and
analyzing the sample, and (d) submitting the report. Discussion of these phases
follows.
Preparing and Planning—In the initial phase of preparation and planning, the
agency must clarify for the source test team leader and process representative all
the procedures and methods to be used during the entire testing program.
The review of the compliance test protocol submitted by the plant management
or test consultant will explain the intended sampling plan to the observer. Two of
the more important items to be checked are any deviations from standard sampling
procedures and the proposed operation of the facility during the compliance test.
Many types of processes, sampling locations, and pollutants require some
modification to the standard sampling procedure. The agency must determine if
the modification will give equivalent and/or greater measurement results than
would be obtained with the standard method.
The other major determination to be made from the test protocol is defining
what constitutes normal operation of the facility. Example checklists for power
plants and electrostatic precipitators are presented.
The plant representative should understand and agree to all facility baseline con-
ditions prior to the compliance testing, since the determination of representative
operation of the facility is for the protection of both the regulatory agency and the
plant. The plant representative may suggest additional factors that could be con-
sidered as an upset condition and which would not produce representative
emissions.
8-5
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Example checklists for power plants.
8.1 FOSSIL FUEL FIRED INDIRECT HEAT EXCHANGE
8.3 FUEL INPUT DATA
Checklist for process monitor
Monitor name
Facility representative
Company name
Designation of facility
Designation of unit being tested _
Maximum heat input
Test date
Boiler nameplate capacity
Electric generator capacity .
Induced draft fan capacity
at
Motor drive
_hp.; amps
Combustion control Automatic
Type of soot blowing Continuous
Control of soot blowing
Automatic sequential
Hand
time cycle
Describe the a.p.c. system
million Kcal/hour
million Btu/hour
_, pounds steam/hr
megawatts
CFM
_; volts _
Hand
Period
Automatic weighing or metering
Counter (totalizer) reading
Time Coal Oil Gas
End test
Begin test
Difference
Units fed during
test
Counter conversion
factor
Fuel per counter
unit tons
Fuel fed during test tons
Fuel sampled
during test
Number of samples
Total quantity of
sample
Date of last
calibration
of automatic
metering device
For manual weighing or other:
Use this space for monitoring procedure and calculations
gal. cu. ft.
gal. cu. ft.
8.2 MONITORING FUEL DURING TEST
Note fuel feed measuring devices may be some distance from
other instrumentation to be monitored.
Coal (classified by ASTMD 388-66)
Bituminous Sub-bituminous Anthracite Lignite
Coal feel measured by
Automatic conveyor scale
Batch weighing — dumping hoppers
Other (describe)
None
Liquid fossil fuel
Crude Residual Distillate
Liquid fuel feed measured by
Volumetric flow meter, make
Other (describe)
None
Gaseous fossil fuel
Natural gas Propane
Other
Gaseous fuel feed measured by
Volumetric flow meter, make
Other (describe)
model _
Butane
model _
Other fuel (describe)
8.4 FUEL ANALYSIS
Proximate analysis—as fired solid and liquid fuels
% by weight
Typical
This test
Component
Moisture
Ash
Volatile matter .
Fixed carbon
Sulfur
Heat value, Btu/lb_
or ultimate analysis —which includes the proximate analysis plus
the following
Nitrogen .
Oxygen
Hydrogen
Other fuel feed measured by
8-6
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8.5 MONITORING BTU INPUT BY HEAT RATE
OF BOILER-GENERATOR UNIT AND
Kw-hr OUTPUT METER WHEN APPLICABLE
Purpose is to serve as a check on other calculation procedures.
Boiler generator heat rate Btu/kw-hr. Heat
rate is obtained from facility representative. The heat rate
curve is more accurate if corrections for super heat
temperature, reheat temperature and condenser back pressure
are applied for the test load condition.
Record data from generator output meter
Time
End test
Begin test
Difference
Kw-hrs. generated during test
Btu input during test =
Kw-hrs. generated X heat rate (Btu/Kw-hr.)
Btu input during test =
X = Btu
Meter reading
Kw-hr Output
8.7 OTHER INSTRUMENTAL DATA
Exhaust gas temperature just before the a.p.c. device
Max °F Min °F Avg °F
Draft
Before control device
After control device
Primary •
Collector
Secondary
Collector
in H2O
in H2O
Combustion recorders (indicate those available)
COg Opacity
02 NOX
SO2
Obtain copy of recorders available and mark beginning and
ending time of test.
• Soot blowing
Was soot blowing to be included in the test period
No Yes
If yes, record time and duration of soot blowing.
1 Special observations of any unusual operating conditions
8.6 MONITORING STEAM GENERATOR OUTPUT
BY STEAM FLOW METER
8.8 ELECTROSTATIC PRECIPITATOR—CHECKLIST
FOR CONTROL DEVICE MONITOR
(Usually combined with air flow)
Steam flow measured by
Integrator on steam flow meter
Integrating chart from recorder
Calibration date
Parameters of design and operation affecting performance
Primary purpose of steam flow monitoring is to indicate the
load on the boiler during the test to observe and communicate
to test team leader sudden significant change in steam flow
which would be accompanied by significant changes in gas
flow. Steam flow and flue gas flow changes parallel each other
closely.
Record data by integrator on steam flow meter
Time Integrator Reading
End test —
Begin test —
Difference
Alternate factor
Total steam flow during test.
pounds
Steam chart
Mark beginning and end of test runs on the steam chart and re-
quest a copy.
Chart marked and copy received.
Monitor name Test date
Design efficiency
Rectifier power output Design During test
Voltage, kilowatts
Current, milliamps
Sparking rate, sparks/min
Gas volume, acfm
Gas velocity, fps
Gas temperature, °F
Fan motor, amperes
Electrical fields in direction of flow
Number of rappers in direction of flow
Other method of cleaning plates
ESP rapping sequence
Normal
During test
Hopper ash removed sequence
Normal
Notes of unusual conditions during test
8-7
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8.9 SCRUBBER—CHECKLIST FOR CONTROL DEVICE
MONITOR
Parameters of design and operation affecting performance
Monitor name Test date
Type of scrubber
Venturi Plate Other
Turbulent bed Spray
Design of efficiency
Design
During test
Pressure drop across scrubber,
in H2O
Nozzle pressure, pounds/sq in
Gas volume flow out of
scrubber, cfm
Fan motor amperes
Liquid flow rate to scrubber
gal/m in
Liquid/gas rates, L/g
Recirculation of scrubbing
liquid
Gas temperature of scrubber
Preconditioning or dilution air
During test
Rates of usual conditions during test ,
8.10 FABRIC FILTER—CHECKLIST FOR CONTROL
DEVICE MONITOR
Parameters of design and operation affecting performance
Monitor name
Pressure drop across
Collector in H%O
Just after bag cleaning
Just before bag cleaning
Gas volume to bag house, acfm
Fan motor amperes
Type of cleaning
Shaking- number of compartments
Reverse air flow —number of compartments
Repressuring —number of compartments
Pulse jet (cleaned while on stream)
Other
Cleaning cycle
Normal
. Test date
Design During test
During tests .
Paniculate removal sequence
Normal
During test
Notes of unusual conditions during test ___
8.11 CYCLONE/MULTICYCLONE—CHECKLIST
FOR CONTROL DEVICE MONITOR
Parameters of design and operation affecting performance
Monitor name „ Test date
Design efficiency
Design During test
Pressure drop across
Collector in H2O
Gas volume, acfm
Gas temperature °F
Fan motor amperes
Is the collector sectionalized with dampers for control of
Ap No Yes
If yes, how were dampers positioned during test?
Hopper ash removal sequence
Normal
During test
Notes of unusual conditions during test _
Preconditioning or dilution air
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The observer must be familiar with the process to be sampled. Whenever
possible, the agency field inspector should be the observer for the process and con-
trol equipment. If the process is large or complicated, the observer may be aided
by a process control engineer from the agency. An emission test run at the wrong
process rating or without sufficient process data will not constitute a valid test.
Familiarity with the specific process can be acquired through one or more of the
many inspection manuals prepared by the Environmental Protection Agency for
this purpose. These manuals will indicate the methods and devices employed in
monitoring process rates and/or weights.
Conducting the Test —Some compliance tests may be routine enough that a
pretest meeting on the morning before sampling begins will be sufficient to provide
a complete understanding between all parties involved.
The review of the team leader's test protocol should have initiated the formula-
tion of the observer's sampling audit plan. The observer's audit plan should contain
the tentative testing schedule, facility baseline conditions preparation or modifica-
tion of observer's checklist, and details for handling irregular situations that could
occur during emission testing. „
The sample testing schedule should allow the observer to plan his duties in a
logical order and should increase his efficiency in obtaining all of the required
data.
The observer's testing forms normally should need little modification. Any
accepted modification to the normal sampling procedure should be covered by
additional checks from the observer.
The observer should be prepared to handle any nonroutine situations that could
arise during sampling procedures. A list of potential problems and their solutions
should be made before the actual testing. The list should include minimum
sampling requirements and process operating rates. The observer should also know
who in his organization is authorized to make decisions that are beyond his own
capability or authority.
The number of agency personnel observing the performance test must be
adequate to ensure that the facility operation (process and control equipment) is
monitored and recorded as a basis for the present and future evaluations. The
observing team should be able to obtain visible emission readings and trans-
missometer data for comparison with measured emission rates and should be able
to ensure that the prescribed agency testing methodology was followed.
The plant representative should be available during testing to answer any ques-
tions that might arise about the process or to make needed process changes. It
should be understood that, if any problems do arise, all three parties would be con-
sulted. Since the observer may approve or disapprove the test, his intentions should
be stated at the pretest meeting.
8-9
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Before actually proceeding with the test, the observer should check the calibra-
tion forms for the specific equipment to be used. As a minimum, these should in-
clude calibration of the:
• Pitot tube
• Nomograph (if used)
• Dry Gas Meter
• Orifice Meter
If there is any question as to whether proper calibration procedures were followed,
the problem should be resolved before initiating the test.
During the test, the outward behavior of the observer is of utmost importance.
He should perform his duties quietly, thoroughly, and with as little interference
and conversation with the source test team as possible. He should deal solely with
the test supervisor and plant representative or have a clear understanding with
them should it become necessary to communicate with the source test technicians
or plant operators. Conversely, he should exercise caution in answering queries
from the source test team technicians and plant operators directly and refer such
inquiries to their supervisor. He should, however, ensure that sampling guidelines
are adhered to and inform the test team if errors are being made.
Several checks must be made by the observer to ensure adherence to the proper
sampling procedures. To eliminate the possibility of overlooking a necessary check,
an observer's checklist should be used for the sampling procedures and facility
operation. An example of one of these checklists is included.
To understand the relative importance of the measurement of parameters of
emission testing, the observer should know the significance of errors. A discussion
of errors is given in a preceding section of this chapter.
Generally, it is best to have two agency observers at the source test. If only one
observer is present, however, the following schedule given should be followed.
For the first Method 5 run, when the facility is operating in the correct manner,
the observer should go to the sampling site and observe the sample train configura-
tion and the recording of the initial data. The observer should oversee the initial
leak check (and the final post test leak check). When the observer is satisfied with
the sample train preparation, the test may be started. The sampling at the first
port and the change-over to the second port should be observed. If satisfied with
the tester's performance, the observer should go to a suitable point from the stack
and read visible emissions for a 6 minute period.
The facility operations must then be checked. This includes data from fuel flow
meters, operating monitors, fuel composition, F factors, etc. Also check data from
continuous emissions monitoring equipment such as opacity monitors and SC>2
analyzers. This data will be useful in evaluating the Method 5 data. If the process
and control equipment have operated satisfactorily and the data has been recorded
as specified, the observer should make another visible emission reading for 6
minutes, then return to the sample site to observe the completion of the test. The
final readings and the leak check after the completion of the test are two of the
more important items to be checked. The transport of the sample train to the
cleanup area and the sample recovery should then be observed.
8-10
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Sampling checklists.
8.12 GENERAL/SAMPLING SITE
8.14 GENERAL/SAMPLING SYSTEM
Stack/duct cross section dimensions
equivalent diameter
Material of construction
corroded? _
leaks?.
Internal appearance: corroded?
caked particulate?
thickness
Insulation? thickness lining? thickness .
Nipple? - I.D. length flush with inside wall? .
Straight run before ports diameters
Straight run after ports diameters
Photos taken? of what
Drawing of sampling location:
Minimum information on drawing: stack/duct dimensions,
location and description of major disturbances and all minor
disturbances (dampers, transmissometers, etc.). and cross sec*
tional view showing dimensions and port locations.
8.13 RUN ASSEMBLY/FINAL PREPARATIONS
(Use one sheet per run if necessary) Run #
Sampling method (e.g.. EPA 5).
Modifications to standard method .
Pump type: fibcrvane with in line oiler
carbon vane diaphragm
Probe liner material .
Type "S" pitol tube?.
heated .
entire length .
other.
Pitot tube connected to: inclined manometer _
or magnehelic gage
range approx. scale length
divisions'
Office meter connected to: inclined manometer
or magnehelic gage range
approx. scale length divisions
Meter box brand sample box brand _
Recent calibration of orifice meter-dry gas meter? .
pilot tubes nozzles
thermometers or thermocouples? magnehelic gages?.
Number of sampling points/traverse from Fed. Reg.
number to be used
Length of sampling time/point desired
time to be used
. nozzle clean? .
Filter holder clean before test?
Filter holder assembled correctly?
Probe liner clean before test?
nozzle undamaged?
Impingers clean before test?
impingers charged correctly? Yes
Ball joints or screw joints? grease used? kind of grease
Pitot tube tip undamaged?
pilot lines checked for lealts?_
plugging?.
Meter box leveled? _ pilot manometer zeroed? _
orifice manomeier zeroed? _
Probe markings correci? _ probe hoi along entire length? -
Filter compartment hot? _ temperature information available? _
Impingers iced down? _ thermometer reading properly? yes
Barometric pressure measured? _ if not . whal is source of dala _
AH@ from mosl recenl calibralion _
AHga from check against dry gas meter _
Nomograph check:
= 1.80, TM = 100°F, %H20=10%, Ps/Pm=1.00.
C= 0.95 (0.55)
If C = 0.95. TS = 200°F, DN = O.S75. Ap
reference = 1.17 (0.118)
Align Ap= 1.0 with AH=10; @Ap = 0.01, AH= 0.1 (0.1)
For nomograph set-up:
Estimated meter temperature _ °F estimated
value of Ps/Pm -
Estimated moisture content _ % how estimaied?
C factor _ estimated stack temperature _ °F
desired nozzle diameier
Stack thermometer checked against ambient temperature?.
Leak test performed before start if sampling?
rate cfm @ in. Hg.
8.15 SAMPLING
(Use one sheet for each run if necessary)
Run*
Probe-sample box movement technique:
Is nozzle sealed when probe is in stack with pump turned
off?
Is care taken to avoid scraping nipple or stack wall?.
Is an effective seal made around probe
at port opening?
Is probe seal made without disturbing flow
inside slack?
•Is probe moved lo each point at the proper time?
Is probe marking system adequate to properly locate each
point?
Was nozzle and pitol lube kepi parallel lo slack wall ai each
point?
If probe is disconnected from filter holder wilh probe' in ihe
slack on a negalive pressure source, how is parliculale
mailer in ihe probe prevented from being sucked back into
the stack?
If filters are changed during a run, was any
paniculate lost?
Meterbox operation:
Is data recorded in a permanent manner
are data sheets complele?
Average lime lo reach isokinelic rate at each point
Is nomograph selling changed when stack temperature
changes significantly?
Are velocity pressures (AT) read and recorded accurately
Is leak test performed at completion of run? cfm ° in. Hg.
Probe, filter holder, impingers sealed adequately
after lesl?
General content on sampling techniques
If Orsat analysis is done, was it: from stack
from integrated bag?
Was bag system leak tesied? was orsai
leak tested? check against air?
If data sheets cannot be copied, record: approximate stack
temperalure °F.
nozzle dia in. volume melered ACF
firsi 8 Ap readings
8-11
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If the observer is satisfied with all sampling procedures during the first run, then
during the second run time will be spent observing the process monitors, with the
exception of checking the sampling team at the end of the sampling period. During
the second run, two 6-minute visible emission readings should be made with a
check of the facility operations between readings. The observer should be satisfied
that the facility data recorded are truly representative of the facility operations.
A visual observation of the particulate buildup on the filter and in the acetone
rinse from the first two tests should be correlated to the visible emission readings or
transmissometer data. This comparison of particulate collected will be valid only if
the sample volumes were approximately the same. If the particulate catch on the
filter and in the acetone rinse for the second test was consistent or greater than the
visible opacity correlated to the first run, then the observer might need to spend
more time overseeing the facility operations. If the second run, when correlated to
the opacity, is less than the first test, more time might be spent in observing the
emission test procedures for the third run.
Regardless of the main emphasis of the third run, the observer should still per-
form certain observations. The observer again should check all facility operations
before testing. Two 6-minute visible emission readings should be made with a
check of the facility operation inbetween. The sample recovery of all tests should
be witnessed, and the apparent particulate catch compared to the opacity readings.
The additional time can be spent by the observer checking suspected weak points
or problem areas.
Recovering and Analyzing the Sample —The observer should be present during
sample recovery. It is imperative that the sample recovery and analysis be done
under standard procedures and that each step be well documented. The report
may ultimately be subject to the requirements of the Rules of Evidence. Therefore,
the observer should have a sample recovery checklist to ensure that all tasks have
been performed properly.
To reduce the possibility of invalidating the results, all of the sample must be
carefully removed from the sampling train and placed in sealed, nonreactive,
numbered containers. It is recommended that the sample be delivered to the
laboratory for analysis on the same day that the sample is taken. If this is imprac-
tical, all the samples should be placed in a carrying case (preferably locked) in
which they are protected from breakage, contamination, loss, or deterioration.
The samples should be properly marked to assure positive identification
throughout the test and analysis procedures. The Rules of Evidence require impec-
cable identification of samples, analysis of which may be the basis of future
evidence. An admission by a lab analyst that he could not be positive whether he
analyzed sample 6 or sample 9, for example, could destroy the validity of an entire
report.
Positive identification also must be provided for the filters used in any specific
test. All identifying marks should be made before taring. Three or more digits
should suffice to ensure the uniqueness of a filter for many years. The ink used for
marking must be indelible and unaffected by the gases and temperatures to which
8-12
-------
it will be subjected. If any other method of identification is desired, it should be
kept in mind that the means of identification must be positive and must not impair
the function of the filter.
Finally, each container should have a unique identification to preclude the
possibility of interchange. The number of a container should be recorded on the
analysis data sheet associated with the sample throughout the test and analysis.
Samples should be handled only by persons associated in some way with the task
of analysis. A good general rule to follow is "the fewer hands the better," even
though a properly sealed sample may pass through a number of hands without
affecting its integrity.
It is generally impractical for the analyst to perform the field test. The Rules of
Evidence, however, require that a party be able to prove the chain of custody of
the sample. For this reason, each person must have documented from whom he
received the sample and to whom he delivered it. This requirement is best satisfied
by having each recipient sign a standard chain of custody sheet initiated during the
sample recovery.
To preclude any omissions of proper procedures after the sample recovery, the
observer should have a sample transport and analytical checklist:
8.16 SAMPLE RECOVERY
General environment — clean up area
Wash bottles clean? brushes clean? brushes rusty.
Jars clean? acetone grade residue on evap. spec. .
Filter handled ok? probe handled ok?
impingers handled ok?
After cleanup: filter holder clean probe liner clean?
nozzle clean? impingers clean? blanks taken
Description of collected paniculate
Silica gel all pink? run 1 run 2 run 3
Jars adequately labeled? jars sealed tightly?
Liquid level marked on jars? jars locked up?
General comments on entire sampling project:
Was the test team supervisor given the opportunity to read over
this checklist?
Did he do so?
Observer's name title
Affiliation signature
Potential sources of error in the analysis lie in the contamination of the sample,
in the analyzing equipment, procedures, and documentation of results. Since the
analysis is often performed at a lab distant from the plant site, the observer is often
not present at the sample analysis. If there is any question in the observer's mind
about the analyst's ability to adhere to good analytical practices in analyzing and in
reporting data, the observer has two recourses: he may be present during analysis
or he may require the analysis be done by a certified laboratory if one is available.
This is, however, an unnecessary burden and should not be done as a general rule.
8-13
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During the analysis, any remaining portions of the sample should remain intact
and placed in a safe place until the acceptance of the final report. Laboratory
equipment, especially the analytical balance, should have been calibrated
immediately before the sample weighing. The laboratory data and calculations
must be well documented and kept in such a manner that the agency can inspect
the recording of any analysis upon request.
As noted in the lectures for this course, the observer should be aware of
analytical tricks that can be used to bring a marginal test to within ±10% of
100% isokinetic. Care should be taken that the value for the nozzle diameter, or Cp
does not change. Also, the weight of the impinger catch and silica gel for the
determination of Bws should not be changed to accommodate a % isokinetic value.
It has been suggested that to ensure an unbiased test, the observer could supply the
source tester with his own preweighed filter and preweighed amount of silica gel.
This may be extreme, but necessary in special cases.
Submitting the Report—Upon completion of the compliance field test work, the
observer can begin the final task of determining the adequacy of the compliance
test data. He will be required to write an observer's report for attachment with the
source tester's report. The facility operation, the data, and the field checklists
should provide the observer with sufficient information to determine the represen-
tativeness of the process and control equipment operation and the sample collec-
tion. All minimum conditions should have been met. If the observer suspects a bias
in the results, this bias should be noted. A resulting bias that can only produce
emission results higher than the true emissions would not invalidate the results if
the plant were determined to be in compliance. Therefore, any bias that may
occur should be listed along with the suspected direction of the bias.
The test team supervisor is responsible for the compilation of the test report and
is usually under the supervision of a senior engineer who reviews the report for con-
tent and technical accuracy. Uniformity of data reporting will enable the agency to
review the reports in less time and with greater efficiency. For this reason, a report
format should be given to the test team supervisor along with the other agency
guidelines.
The first review of the test report should be made by the observer. The observer
should check all calculations and written material for validity. One of the greatest
problems in compliance testing is in the calculation errors made in the final report.
Several agencies have gone to the extreme of having the observer recalculate the
results from the raw data to find any error more easily. Errors should be noted
along with comments by the observer. Although the conclusions in the observer's
report are not the final authority, they should carry the greatest amount of weight
in the final de :ision concerning the representativeness of the test.
Because of the importance of the observer's report and the possibility that it may
be used as evidence in court, the observer should use a standard report format that
will cover all areas of representativeness in a logical manner. An example of an
observer's report format is presented.
8-14
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8.17 OBSERVER'S REPORT FORMAT
Cover
1. Plant name and location (Federal AQCR)
2. Source sampled
3. Date sampled
4. Testing firm
5. Control agency
Certification
1. Certification by observers)
2. Certification by author if not observer
3. Certification by key agency personnel
Introduction
1. Agency name
2. Purpose for observer's report
3. Purpose for test
4. Plant name, location and process type
5. Test dates
6. Pollutants tested
7. Applicable regulations
8. Agency sections and personnel directly involved
Summary of Representativenev of Data
1. Compliance test protocol
2. Calibration of sampling equipment
3. Process data
4. Control equipment data
5. Sampling procedures
7. Analytical procedures
8. Compliance test report
Facility Operation
1. Description of process and control device*
2. Baseline conditions
3. Observer's facility data (checklists)
4. Representativeness of process and control device
5. Baseline conditions for agency inspector
Sampling procedures
1. Acceptability of sample port and point locations
2. Compliance test protocol
3. Calibration of sampling equipment
4. Observer's sampling data (checklist)
5. Representativeness of sampling
6. Observer's sample recovery data (checklist)
7. Representativeness of recovered sample
8. Observer's analytical data
9. Representativeness of sample
Compliance Test Report
1. Introduction
2. Summary of results
3. Facility operation
4. Sampling procedures
5. Appendices
Appendices
A. Copy of pertinent regulations
B. Related correspondence
C. Compliance test protocol
D. Observer's checklists
E. Observer's test log
F. Other related material
In addition to the determination of representative data for the compliance test,
the observer should report all conditions under which the facility must operate in
the future to maintain their conditional compliance status. These conditions will be
reported to the facility as conditions of their acceptance.
These reports and the conditions of the compliance acceptance will provide any
agency inspector with sufficient data to conduct all future facility inspection trips.
8-15
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Chapter 9
Additional Topics
A. SOURCE SAMPLING TRAIN CONFIGURATIONS
The Environmental Protection Agency has developed testing procedures to
evaluate the standard of performance for stationary sources. The Federal Register,
August 18, 1977, describes the reference methods to be used for the performance
test and outlines in Reference Method 5 the procedures and equipment to be
followed in determining particulate emissions from stationary sources. An
equivalent method subject to approval by the Administrator may be used when
emissions from a given facility are not susceptible to being measured by Reference
Method 5. The Reference Method determination of particulate emissions is based
on the Federal Register definition of "particulate" in Subpart D §60.41 (c):
"Particulate matter" means any finely divided liquid or solid
material, other than uncombined water, as measured by
Method 5.
This is a legal definition. A source test engineer must also have a scientific
definition.
Reference Method 5, as written in the August 18, 1977 Federal Register, is
presented schematically in Figure 9-1.
9-1
-------
Stack
I
f
Gas at
stack
tempera-1
ture and {
pressure
Heated
r
Orifice meter
probe -T-
Filter maintained at
248°±250F(120°±14°C)
or temperature specified
in subparts of 40CFR60
Condenser—Pump—Dry gas meter
Figure 9-1. Schematic diagram of Reference Method 5
Analytical procedures for the method require the following:
1. Filter glass mat and particulates be desiccated to constant weight
±0.5 mg.
2. Probe, nozzle, and filter holder be washed with acetone.
a. Acetone blank (100 ml) evaporated at room temperature and pressure.
b. Acetone and particulates evaporated at room temperature and pressure
in a tared weighing bottle.
c. Particulates desiccated and weighed to constant weight ±0.5 mg.
3. Silica gel weighed to nearest gram.
4. Volume H£O in condenser measured and recorded. H2O discarded.
The schematic sampling train and the outline of the analytical procedure re-
quired constitute a scientific definition of the "paniculate." The temperature and
pressure at which a solid or liquid particulate is caught on the filter mat are
defined. Also given are the portions of the sampling train which are analyzed for this
particulate.
There are a number of other source sampling methods available for isokinetic
sampling. The configuration of the sampling train and the analytical procedures
employed can effect the definition of ''particulate matter."
Stack
Filter
r
t
Heated
Gas at
stack
condition:
probe
I Orifice meter
•Condenser Pump Dry gas meter
Figure 9-2. Schematic diagram of an in-stack train.
9-2
-------
The In-Stack Filter
A schematic diagram of an in-stack train is illustrated in Figure 9-2. The filter is
maintained at stack temperature and pressure. The analytical procedures are an
important factor in defining the total "paniculate matter" sampled by .the system.
Typical analytical procedures assess particulate matter on the filter mat only.
This system would, therefore, define only solid or liquid particulates at stack
conditions. Particulates penetrating the filter and settling in the probe or condenser
might be ignored. Gaseous pollutants that might be solid or liquid at 248 ° ± 25 °F
would be trapped in the condenser. If analysis excludes the condenser catch, these
particulates would not be part of the "particulate matter." The gases condensing in
a water trap could become complex and form psuedo-particulate that could bias
the sample. The use of this type of system must be carefully evaluated in the
context of the test objectives and source operating conditions.
Gas at
stack
conditions
Orifice meter
Condenser — Filter — — Condenser— Pump— Dry gas meter
T
At ambient temperature
and pressure
Figure 9-3. Schematic diagram of EPA Method 5 (Modification No. 1)
EPA Method 5 (Modification No. 1)
The schematic for this modification is illustrated in Figure 9-3. The system uses an
out-of-stack filter at ambient temperature and pressure. The filter is located
between the first and second condenser. This is similar to the diagram for Federal
Register Method 8. It traps gases and liquids and solids in the condenser and on
the filter. The system could be used for particulate sampling. The filter particulate
matter would, however, be trapped at a temperature much lower than the
248°±25°F recommended for Method 5. Analytical procedures for particulate
matter in the first and second condensers could be biased by psuedo-particulate
formation. When used for particulate testing, this system must be evaluated in the
context of test objectives and source operations.
9-3
-------
Stack
t
Gas at
stack
conditions
Heated
probe
Filter — Condenser —
r
Filter -Pump DGM
Orifice
meter
t
At ambient temperature
and 1 atmosphere
Figure 9-4. EPA Method 5 (Modification No. 2)
EPA Method 5 (Modification No. 2)
This modification depicted in Figure 9-4 shows filters located both behind and in
front of the condenser. The front filter is maintained at Federal Register
recommendations of 248°±25°F. The second filter is at ambient temperature and
pressure. This system would trap particulates on the filters and in the condenser.
The selective analysis of various parts of the train could be very important. The
system could be subject to the biases noted in the other systems. It can, however,
give a full assessment of particulates emitted at a source.
Stack
Heated
r
Orifice
meter
I * liter - —
Gas at
stack
conditions
probe
filter
t
At 248° ±25 °F (120° ±
and
1 atmosphere
Condc
14 °C)
' Pump ~~~ Dry gas meter
Figure 9-5. Combined system.
The diagram (Figure 9-5) shows an in-stack filter backed up with an out-of-stack
filter maintained at 248°±25°F. The system could assess in-stack particulates,
Method 5 particulates, and ambient particulates. The scope of particulates
measured would depend upon the analytical procedure. This system could be a
useful research tool.
9-4
-------
Summary
The Clean Air Act requires that air pollution be prevented and controlled. The
Federal Regulations emanating from this for control of source emissions require
source emissions performance tests. Paniculate emissions testing procedures are
outlined in Federal Register, August 18, 1977, Method 5. Alternative procedures
may be used if the Method 5 test can not be performed at a given facility; these
alternative procedures must have Administrator approval.
The regulations define "paniculate matter" in terms of Reference Method 5. An
examination of the Method 5 system gives insights into the scientific definition of
particulate as assessed by this sampling method. Alternative systems to Method 5
can have an effect on the definition of "particulate matter." "Particulate matter,"
as defined by these systems, depends upon the temperature and location of the col-
lection filter and the selective analysis of sampling train sections. Any sampling
system used for a particulate emissions performance test must be capable of
assessing the best available system of emissions reduction. The sampling train must
be designed and analyzed within the context of these objectives and source
operating conditions.
B. REPORTING IN UNITS OF THE STANDARD: F-FACTOR METHODS
F Factors: Introduction
The use of the F factor in calculating particulate emission levels from new sta-
tionary sources was promulgated in the October 6, 1975 Federal Register. The F
factor is intended to reduce the amount of data necessary to calculate particulate
emissions in terms of the standard expressed as pounds per million Btu heat input
(Ibs./lO^ Btu). As mentioned earlier, there are currently three types of standards
for particulate mass
concentration standards cs (ppm, grains/ft^, grams/dscm)
pollutant mass rate
standards pmrs (Ibs/hr, Kg/hr)
process rate standards E (Ibs./lO6 Btu, ng/J, Ibs/ton)
The emission rate, in terms of the units given in the New Source Performance
Standards, is related to concentration and mass rate in the following manner
(Eq.9-1) B
OH Q»
where Qs is, of course, the stack gas volumetric flow rate (units of ft.Vhr.,
NmVhr).
and
QH is the heat input rate, the rate at which combusted fuel supplies heat to the
boiler or other heat utilization system (Btu/hr, Kcal/hr)
9-5
-------
By dimensional analysis, it can be seen that the units of E in terms of pollutant
mass per unit of heat input are
(Eq.9-2)
£=
ihr = (Ibs /ft
*/h
l06Btu/hr
u /hr
To obtain emission rates in units of Ibs/lO^Btu, it is necessary for the source
sampler to obtain the following information:
1. pollutant concentration, cs
2. effluent volumetric flow rate,
3. heat input rate,
a. pollutant mass captured
b. dry gas volume sampled
a. stack gas velocity
b. stack temperature
c. stack pressure
d. dry gas composition
(Orsat) % C02, % O2, %
e. moisture content
a. fuel input rate
b. proximate analysis of fuel
N2
Although all of the quantities for cs and Q$ are obtained in a source test, the
quantities making up the heat input rate Q^ may not be easily obtained. Once
obtained, their accuracy may be in doubt since the source sampler usually is not
able to calibrate or check the accuracy of the source fuel flow meter. The represen-
tative nature of the fuel sample and the accuracy of the fuel analysis itself may be
difficult to determine. Consequently, a factor, based on simple principles of com-
bustion was developed to avoid many of the problems involved in the calculation of
E. By using the F factor, E may be simply obtained from the formula
E = c,F(
5
20 9
)
(Eq.9-3)
20.9-%02
The F factor essentially replaces the ratio Q^/ Q^ and the term in brackets is
merely an excess air correction.
The F factor is useful in calculating emissions for paniculate matter. In the case
of its application to continuous monitoring instrumentation for gases, it is even
more valuable. The use of the F factor and its variants (Fc and Fw factors), in
reporting continuous monitoring data in terms of Ibs /lO^Btu heat input, enables
the source operator to monitor only the pollutant gas concentration and the O2 or
CO2 concentration. Without this method, it would be necessary to continuously
monitor st tck gas velocity, temperature, fuel input rate, etc. This would be possi-
ble, but impractical and expensive.
In the sections below, the derivation and uses of the F factor, will be discussed
further. Also, the requirements of 40CFR60.46 for the use of the F factor in
Method 5 will be given.
9-6
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Derivation of the F Factor Method
Before proceeding with the derivation of the F factor, it is necessary to give a few
definitions used in combustion analysis, namely those for "proximate analysis,"
"ultimate analysis," and "gross calorific value."
Proximate analysis —a fuel analysis procedure that expresses the principal
characteristics of the fuel as
1. % moisture
2. % ash
3. % volatile matter
4. % fixed carbon
5. % sulfur
Total 6. heating value (Btu/lb.)
100% 7 asn fusion temperature
Ultimate analysis—the determination of the exact chemical composition of the fuel
without paying attention to the physical form in which the
compounds appear. The analysis is generally given in terms of
percent hydrogen, percent carbon, percent sulfur, percent
nitrogen, and percent oxygen.
Gross Calorific Value (GCV) —also termed the "high heating value." The total
heat obtained from the complete combustion of a fuel.
Referred to a set of standard conditions. The GCV is obtained
in the proximate analysis as the "heating value."
These definitions generally apply to the fuel "as received" at the plant.
If one considers the volume of gas generated by the combustion of a quantity of
fuel, the F factor relationship can be easily obtained. First, defining Vt as the
theoretical volume of dry combustion products generated per pound of fuel
burned in dscf/lb, the following equality can be made
(Eq.9-4) — (excess air \ = V
* f\ I fff^iviuff^ s+t»S\m I
I correction I GCV
\ I
Dimensionally, this says
ft 3/hr _ ft 3
Btu/hr Btu
Qy and Qjj can be determined at the source. V± is obtained from the ultimate
analysis of the fuel.
Remembering the first equation given in this section,
E= - and substituting in Equation 9-4,
OH
cv
E=
GC V / excess air \
\correction)
9-7
-------
The quantity Vt/GCV is then defined as the Fj factor and the following
simplified equation is obtained.
(Eq.9-5) E = cs
I excess air\
^correction/
For EPA Method 5, the oxygen concentration of the source must be determined
simultaneously and at the same traverse. Since the excess air correction using per-
cent oxygen is
/20.9-%02\
\ 20.9 /
the equation to be used for calculating emissions for EPA Method 5 is
„ / 20.9 \
(Eq.9-6)
20.9-%02
As mentioned earlier, there are different types of F factors. The differences arise
in the way in which the excess air corrections are determined. For example, the Fc
factor is used when the percent CO^ is determined instead of percent O<£. (Note:
the Fc factor is not promulgated for use in calculating particulate emissions,
although it may be used in reporting continuous monitoring data for gases). A
table of F factors is given for reference.
It should also be noted that the F factor may be used with the percent O2 and cws
determined on a wet basis if the moisture content Bws of the stack is known:
„ / 20.9
(Eq.9-7) E = cwsF
. 20.9(1-
Note: The subscript w stands for measurements made on a wet basis. All other measurements are
assumed to be made on a dry basis.
9-8
-------
Fac-
tor
Fd
Fc
Fw
F0
Excess Air
Units
dscf
106Btu
dscf
106 Btu
wscf
106 Btu
N.
Measurement
Required for
Emissions
Determination
%02
(dry basis)
% CO2 (dry or
wet basis)
% O2 (wet
basis)
Calculations
E-cF, r 2°-9 i
~" a |_20.9-%02dJ
E CF r io° i
s c [ % C02 J
E c F r 2°-9 i
^ cwsrw
L 20.9(1 -Bwa)-%02wJ
20.9 Fd 20.9-%02
0 100 Fc %C02
Comments
cs deter-
mined on dry
basis
cs on dry or
wet basis con-
sistent with
CO2
measurement
The "wet" F
factor, cws
and %O2 on
wet basis
Bwa = average
moisture con-
tent of
ambient air
Miscellaneous
factor useful
for checking
Orsat data
Table 9-1. F factors.
Calculation and Tabulation of F Factors
The F(j factor method carries with it the assumption that the ratio, Vt/GCV, the
ratio of the quantity of dry effluent gas generated by combustion to the gross
calorific value, is constant within a given category. This ratio, of course, is the
Ffi factor.
Vf is determined from the stoichiometry of the combustion reaction; i.e., if a
hydrocarbon is burned in air, gaseous products will result, the volumes of which,
can be calculated. For example,
C$ //g 4- O2 + N2
propane air
•CO2t +//2Ot+./V2t .
gases
9-9
-------
For each pound of fuel undergoing perfect combustion, a known amount of
gaseous products will result. Using the stoichiometric relationships resulting from
chemical reactions similar to the example above, and given the gross calorific
value of the fuel per pound, the following relationships have been developed for
the F factors.
(Eq.9-8)
227.0(%//) + 95.7(%C)+35.4(%5) + 8.6(%AQ-28.5(%0) (metric
d ~ GCV ~
106[3.64(%H)+1.53(%C) + 0.57(%5) + 014(%N)-0.46(%0)]
d GCV
(Eq.9-9)
F _ 20.0(%C) (metric units)
c GCV
=
c
321X1Q3(%C) (English units)
GCV
(Eq.9-10)
_ 347.4(%H) + 95.7(%C) + 35.4(%S) + 8.6(%AO-28.5(%0)+13.4(%H20).
w GCVW (metric units)
106[5.56(%//)+1.53(%C) + 0.57(S
w~
GCVW (English units)
If the source utilizes a combination of fossil fuels, a simple addition procedure
can be used to compute the F factor.
where
x,y,z = the fraction of total heat input derived from gaseous, liquid, and solid fuels,
respectively.
F\, F2,F$ = the value of F for gaseous, liquid, and solid fossil fuels, respectively.
Several F factors have been calculated for various types of fossil and waste fuels.
It has been found that for a given type of fuel the F factor does not vary over a
significantly large range. For example, for bituminous coal, the F^ factors were
found to range from values of 9750 dscf/lO^ to 9930 dscf/lO^Btu, giving a max-
imum deviation from the midpoint value of 9820 dscf/lO^Btu of less than 3 per-
9-10
-------
cent. In general, it has been reported that the F^ factor can be calculated to within
a ± 3 percent deviation and the Fc factor can be calculated to within a ± 5.9 per-
cent deviation. The calculated factors are given in the following table.
F Factors for Various Fuels a>°
FUEL TYPE
Coal
Anthracite
Bituminous
Lignite
Oil
Gas
Natural
Propane
Butane
WnoH
W LJvMJ.
\\frtf\f\ Rarlr
VVUUU DaiK
Paper and Wood Wastes0
Lawn and Garden Wastes'*
Plastics
Polyethylene
Polystyrene
Polyurethane
Polyvinyl Chloride
Garbage6
Miscellaneous
Citrus rinds and seeds
Meat scraps, cooked
Fried fats
Leather shoe
Heel and sole composition
Vacuum cleaner catch
Textiles
Waxed milk cartons
Fd
dscf/106 Btu
10140 (2.0)
9820 (3.1)
9900 (2.2)
9220 (3.0)
8740 (2.2)
8740 (2.2)
8740 (2.2)
Q9sn n Ql*
^£*\j\J i l.JJ
Qfi40 (4. 1\
&\j^\j \^t* i )
9260 (3.6)
9590 (5.0)
9173
9860
10010
9120
9640 (4.0)
9370
9210
8939
9530
9480
9490
9354
9413
Fw
wscf/106 Btu
10580(1.5)*
10680 (2.7)
12000 (3.8)
10360 (3.5)
10650 (0.8)
10240 (0.4)
10430 (0.7)
FC
scf/106 Btu
1980(4.1)
1810 (5.9)
1920 (4.6)
1430(5.1)
1040 (3.9)
1200(1.0)*
1260(1.0)
1840 fi 01
1 O"v 1 J.wl
IflfiO (% f\\
1OUVS \^,J.\Jf
1870 (3.3)
1840 (3.0)
1380
1700
1810
1480
1790 (7.9)
1920
1540
1430
1720
1550
1700
1840
1620
F
o
1.070 (2.9)
1.140 (4.5)
1.0761(2.8)
1.3461 (4.1)
1.79 (2.9)
1.51 (1-2)*
1.479 (0.9)
1 0>i fS 41
i . V*J \ J.^^
i o^fi 13 Q\
l.V/Jw IJ.JI
1.046(4.6)
1.088(2.4)
1.394
1.213
1.157
1.286
1.110(5.6)
1.020
1.252
1.310
1.156
1.279
1.170
1.060
1.040
a Numbers in parentheses are maximum deviations (%) from the midpoint F factors.
b To convert to metric system, multiply the above values by 1.123 x 10"^ to obtain scm/10^ cal.
c Includes newspapers, brown paper, corrugated boxes, magazines, junk mail, wood, green
logs, rotten timber.
^ Includes evergreen shrub cuttings, flowering garden plants, leaves, grass.
e Includes vegetable food wastes, garbage (not described).
* All numbers below the asterisk in each column are midpoint values. All others are averages.
9-11
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Application of the F Factor to EPA Method 5
It appears that much confusion has arisen with regard to the use of the F factor in
reporting Method 5 data. In the Code of Federal Regulations, 40CFR60.46, under
Test Methods and Procedures for the New Source Performance Standards, emis-
sions expressed in terms of Ib/lO^ Btu are to be determined using the formula
90 Q
(Eq.9-12) E=csFd - — -
H s a 20.9-%02
Reproduced below is: "PART 60— STANDARDS OF PERFORMANCE FOR NEW
STATIONARY SOURCES."
Subpart D — Standards of Performance for Fossil-Fuel Fired
Steam Generators
§ 60.46 Test methods and procedures.
(a) The reference methods in Appen-
dix A of this part, except as provided
in § 60.8(b), shall be used to determine
compliance with the standards as pre-
scribed in §§ 60.42, 60.43, and 60.44 as
follows:
(1) Method 1 for selection of sam-
pling site and sample traverses.
(2) Method 3 for gas analysis to be
used when applying Reference Meth-
ods 5, 6 and 7.
r~ (3) Method 5 for concentration of
particulate matter and the associated
I moisture content.
(4) Method 6 for concentration of
SO3, and
(5) Method 7 for concentration of
NO..
(b) For Method 5, Method 1 shall bel
used to select the sampling site and
the number of traverse sampling
points. The sampling time for each
run shall be at least 60 minutes and
the minimum sampling volume shall
be 0.85 dscm (30 dscf) except that
smaller sampling times T volumes,
when necessitated by process variables
or other factors, may be approved by
the Administrator. The probe and
filter holder heating systems in the
sampling train shall be set to provide a
gas temperature no greater than 433
K(320°F).
(c) For Methods 6 and 7, the sam-
pling s ce shall be the same as that se-
lected "or Method 5. The sampling
point ii the duct shall be at the cen-
troid ol he cross section or at a point
no close io the walls than 1 m (3.28
ft). For M 'thod 6, the sample shall be
extracted at a rate proportional to the
gas velocity at the sampling point.
(d) For Method 6, the minimum
sampling time shall be 20 minutes and
the minimum sampling volume 0.02
dscm CO.71 dscf) for each sample. The
arithmetic mean of two samples shall
constitute one run. Samples shall be
taken at approximately 30-minute in-
tervals.
(e) For Method 7, each run shall
consist of at least four grab samples
taken at approximately 15-mlnute in-
tervals. The arithmetic mean of the
samples shall constitute the run value.
(f) For each run using the methods
specified by paragraphs (a)(3), (a)(4),
and (a)(5) of this section, the emis-
sions expressed in ng/J (Ib/million
Btu) shall be determined by the fol-
lowing procedure:
E=CF(20.9/20.9-percent O,)
where:
(1) E = pollutant emission ng/J (lb/
million Btu).
(2) C = pollutant concentration, ng/
dscm (Ib/dscf), determined by method
5, 6, or 7.
(3) Percent O,=oxygen content by
volume (expressed as percent), dry
basis. Percent oxygen shall be deter-
mined by using the integrated or grab
sampling and analysis procedures of
Method 3 as applicable.
The sample shall be obtained as fol-
lows:
(i) For determination of sulfur diox-
ide and nitrogen oxides emissions, the
oxygen sample shall be obtained si-
multaneously at the same point in the
duct as used to obtain the samples for
Methods 6 and 7 determinations, re-
spectively [§60.46(c)]. For Method 7,
the oxygen sample shall be obtained
using the grab sampling and analysis
procedures of Method 3.
(ii) For determination of particulate
emissions, the oxygen sample shall be
obtained simultaneously by traversing
the duct at the same sampling location
used for each run of Method 5 under
paragraph (b) of this section. Method
1 shall be used for selection of the
number of traverse points except that
no more than 12 sample points are re-
quired.
(4) F = a factor as determined in
paragraphs (f) (4), (5) or (6) of §60.45.
9-12
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(g) When combinations of fossil
fuels or fossil fuel and wood residue
are fired, the heat input, expressed in
watts (Btu/hr), is determined during
each testing period by multiplying the
gross calorific value of each fuel fired
(in J/kg or Btu/lb) by the rate of each
fuel burned (in kg/sec or Ib/hr). Gross
calorific values are determined in ac-
cordance with A.S.T.M. methods D
2015-66(72) (solid fuels). D 240-64(73)
(liquid fuels), or D 1826-64(7) (gaseous
fuels) as applicable. The method used
to determine calorific value of wood
residue must be approved by the Ad-
ministrator. The owner or operator
shall determine the rate of fuels
burned during each testing period by
suitable methods and shall confirm
the rate by a material balance over the
steam generation system.
(Sec. 114, Clean Air Act as amended (42
U.S.C. 7414))
[40 PR 46258. Oct. 6. 1975. as amended at 41
PR 53199. Nov. 22, 1976]
There are three points that should be made here:
• Only the dry F factor using percent O2 for the excess air correction may be
used in the calculation. The Fc and Fw factors may not be used.
• The oxygen sample is to be obtained simultaneously with the Method 5 run, at
the same traverse points. This essentially requires that an additional probe be
placed along with the Method 5 probe and an additional pump be used to
obtain an integrated bag sample over the duration of the run. However, only
12 sample points are required. If there are more than 12 traverse points deter-
mined by EPA Method 1, an independent integrated gas sampling train could
be used to traverse 12 points in the duct simultaneously with the paniculate
run.
• The procedures in 40CFR60.46 apply to new fossil-fuel fired steam generators
(new sources are those constructed or modified after August 17, 1971). For
existing fossil-fuel steam generators, which are regulated by State standards,
the State or local regulations should be checked for application of the F factor
method.
Other Uses of F Factors
A. If values for Q^, the stack gas volumetric flow rate, and Q// tne neat input
rate, are obtained during the source test, as they often are, several cross-
checks can be made by comparing various calculated F factor values with
the tabulated values. Equations that can be used to do this are given below.
(Eq.9-13)
Fd(calc) =
(20.9-%02)
209
(Eq.9-14)
Fw (calc) =
(Eq.9-15) Fc(calc) =
100
9-13
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If, after calculating F^, Fc, or Fw, a large discrepancy exists between the calculated
value and the corresponding value in the table, the original data for Qj, Q//, and
the Orsat data should be checked. This is an easy way of conducting a material
balance check.
B. Using a tabulated value for F^, Fc, or Fw and the data obtained during the
stack test for Q^ and %O% or %CO%, a value of QH maY be obtained from
the equations.
C. If ultimate and proximate analyses are available, they may be used to
calculate an F factor using one of the equations. The calculated value can
then be checked with the tabulated values and should be within 3 to 5 per-
cent agreement, depending on the type of fuel and type of F factor.
D. The F0 factor may be used to check Orsat data in the field.
The F0 factor is the ratio
^ 20-9 Fd
(Eq.9-16) Fo-
and is equal to
/20.9-%02
" \ %co2 /
the %O2 and %CO2 being obtained or adjusted to a dry basis. A value differing
from those tabulated would necessitate a recheck of the Orsat data.
Errors and Problems in the Use of F Factors
The following factors may contribute to errors in reporting emiss: jiiS ~y using
F factors:
• Deviations in the averaged or "midpoint" F factor value itself.
• Errors in the Orsat analysis and the consequent %O^ and %CO^ values.
• Failure to have complete combustion of the fuel (complete combustion is
assumed in the derivation of all of the F factor methods)
• Loss of CC>2 when wet scrubbers are used — affecting the F^, Fc and Fw factors.
Addition of CO% when lime or limestone scrubbers are used — affecting the Fc
factor.
The deviations in the F factors themselves have been found to vary no more than
about 5 percent within a given fuel category. Since the F factors given are averaged
values, differences in the ultimate analysis between fuel samples could easily
account for the deviation. The most significant problem in the use of the F factors,
however, is in the excess air correction— the use of the Orsat data in calculating
the paniculate emissions. An error of a few percent in the oxygen concentration
could cause a relatively large error in the value of E, or more importantly, could
9-14
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mean the difference between compliance and noncompliance. A recent publication
by Mitchell and Midgett (1976), entitled "Field Reliability of the Orsat Analyzer,"
states
The results from five collaborative tests of the Orsat Method
indicate that the use of Orsat data to determine the molecular
weight of flue gases is a valid procedure, but the use of such
data routinely to convert paniculate catches to such reference
conditions as 12% CO% and 50% excess air may introduce
sizeable errors in the corrected paniculate loading....
However, since the use of Orsat data for calculating par-
ticulate conversion factors will likely continue it seems prudent
to develop procedures to check the reliability of Orsat data.
One procedure, that could be instituted without affecting
either the cost or time of a source test, would be to require that
if the Orsat data is to be used for calculating a paniculate con-
version factor, then the integrated flue gas sample must be
independently analyzed by at least two analysts and their
results for each gas component must agree within a certain
volume percent —say 0.3%—before they can be used to
calculate the conversion factor.
Since the F factor method has been developed assuming complete combustion of
the fuel, incomplete combustion will cause an error. However, if the %CO is deter-
mined in the flue gas, some adjustment can be made to minimize this error.
(Eq.9-17) (%C02)adj=%C02+%CO
(Eq.9-18) (%02)adj= %02-0.5 %CO
By making these adjustments, the error amounts to minus one-half the concen-
tration of CO present.
The loss of CO2 in wet scrubbing systems will also have an effect on the
F factors. A 10% loss of CO2 will produce an approximate 10% error in the Fc
factor. Since the Fj factor (O2 correction) is based on source combustion products,
its value will also be affected by the loss of CO2. If the gas stream has 6% O2 and
1.4% CO2 is lost in the scrubber, the error will be about plus 2.8%. The Fw factor
is not applicable after wet scrubber since the moisture content would have to be
independently determined.
In general, the greatest errors associated with the F factor method are those that
would be associated with the excess air correction. Collaborative testing programs
have found that such errors can range as high as 35% when emission rates are cor-
rected to 12% CO2. F factors can be a valuable tool in calculating source emissions
in terms of the New Source Performance Standards; however, care should be taken
in their application. Considerable effort should be given by the source sampler to
obtain representative and accurate Orsat data.
9-15
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C. PARTICLE SIZING
Particle Sizing
A particle has several important properties. These are mass, dimension, chemical
composition, aerodynamic properties, and optical properties. The primary
distinguishing feature of any particle is the particle size. The most widely used unit
describing particle size is the micron.
/ micron (fi) = 0.001 mm = 10 ~ 4cm = 10 ~ 6 meter
Particle size may be determined by a variety of analytical techniques. The
analysis of particle size is misleading since in practice these techniques do not
measure actual particle size, rather they measure particle properties related to the
particle size and shape. Analytical or empirical relationships incorporating
theoretical principles and assumptions are then employed to assign the particle an
"effective size." Particle size analysis is influenced by the extreme diversity of
particle shape. Size analysis data can be widely different depending upon the
methods employed for analysis. The analytical methods used for size analysis must,
therefore, be carefully considered in terms of the objective purpose for which the
size analysis is required.
Particle Physical Properties
The term "particle size" generally refers to an "effective size" described as an
equivalent or effect diameter. A large amount of empirical and theoretical infor-
mation has been developed for describing the physical properties of spheres of unit
density in dry air. The data can be applied in predicting the physical
properties — mass, volume, or settling velocity — for any particle if the particle size
can be defined in terms equivalent to the terms used in describing a sphere. The
most convenient and frequently used common term is "diameter": the particle size
is described in terms of a sphere of equivalent diameter. Assuming that the
physical properties of the r irticle will be similar to those of a sphere of the
equivalent diameter and that a physical property (f) is proportional to some power
of the diameter(d), the prediction can be made:
(Eq.9-19) f(d) =
where n = a number (determined empirically or theoretically)
a = a shape factor specific for particles of a given shape and
composition
This is ex emely important for the design of emissions control devices. The
important paiameters involved in operating and maintaining emissions control devices
can be fully evaluated only after adequate particle size information has been obtained.
Particle Motion
The most common and useful particle sizing methods for solid particles suspended
in a gas define particle >ize as an aerodynamic diameter. This allows the prediction
of the aerodynamic properties of a particle. These properties are extremely impor-
9-16
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tant in designing control equipment to remove particles suspended in a gas emitted
to the atmosphere. The procedures employed rely on several principles of fluid
dynamics and the calculations made by investigators Stokes and Cunningham. The
principles involved will be discussed to aid in understanding the operation of the
devices for determining particle aerodynamic diameter.
The Mechanism of Drag for Submerged Particles
The flow phenomena of a nonviscous, incompressible fluid around a submerged
object is explained by the Equation of Continuity and Bernoulli's theorem. The
diagram in Figure 9-6 illustrates the streamlines of the fluid. The velocity of a fluid
molecule perpendicular to a tangent drawn at point I falls to zero. The incom-
pressible fluid particles flowing around the object follow the principles in the equa-
tion of continuity; the streamlines come closer together with a resultant increase in
acceleration. The acceleration at point II is accompanied by a decrease in pressure
as described by Bernoulli, i.e., the net work done on the fluid by pressure must be
equal to the net gain in mechanical energy. Fluid mass and energy must be con-
served in a nonviscous, incompressible system, therefore, as the fluid flows around
the body to point III it releases mechanical energy, increasing the pressure. The
fluid decelerates to its original velocity and the system pressure returns to the values
at point I. Fluid streamlines in this ideal system are symmetrical in front of and
behind the submerged body.
The flow of viscous, compressible fluid around a submerged object may also be
examined and understood in the context of the equation of continuity and
Bernoulli's theorem. The nonviscous, incompressible fluid flows around the object
without losing energy. The viscous, compressible fluid would experience surface
Figure 9-6. Submerged particle.
9-17
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drag or friction as it passes from point I to point II. The equation of continuity
shows that the accelerating fluid would increase the fluid mass per cross-sectional
area per unit time passing from point I to point II. The fluid would "pile up" dur-
ing its flow, increasing the fluid density and changing the Reynolds Number of the
fluid. The friction from surface drag dissipates part of the mechanical energy of
the fluid as heat. The fluid cannot return mechanical energy as pressure,
therefore, fluid pressure at a distance beyond point II is lower than the pressure of
the fluid at point I or point III. The Reynolds Number changes are caused by
changes in fluid density and viscosity. Increased viscosity creates tangential forces
which in conjunction with the opposition forces of higher pressure at point III
acting on the accelerated fluid force it to disassociate with the fluid streamlines
behind the body. The accelerated fluid must find somewhere to flow since it can-
not rejoin the original streamline. The forces acting upon the fluid cause it to flow
in a reverse, tangential pattern forming a vortex behind the body. The continued
fluid flow around the submerged body with continuously changing Reynolds
Number quickly sweeps the vortex formed downstream. A new vortex forms and
the interaction of these vortices results in a turbulent wake behind the submerged
body. The net effect on the submerged body is frictional and pressure drag.
Stokes' Law
The motion of a body submerged in a fluid is determined by the forces acting
upon the body. A particle will remain at rest with respect to fluid in which it is
located until it is acted upon by some external force. This principle is Newton's
first Law of Motion. It is further explained in his second law, which states that the
acceleration upon a body caused by a force is proportional and parallel to the
result of that force and inversely proportional to the mass of the body. A single
isolated force is an impossiblity since any force acting upon a body L at. .ually only
one aspect of a mutual interaction between two bodies. A body exerting a force
upon another body always encounters an equal and oppositely directed force
exerted by the second body. This principle is Newton's third Law of Motion. The
application of these laws upon a sphere of unit density falling in dry air is the basis
for Stokes' Law.
Newton's first law is contained in his second law since if the force (F) acting
upon a body is F=0, then the acceleration (a) of the body is a = 0. In the absence
of an applied force, the body will move at a constant velocity. This concept makes
possible the calculation of the constant terminal or settling velocity of a body
suspended in a fluid. If the magnitude of the forces acting upon the body and the
size and shape of the body are known, its terminal velocity can be computed. A
convenient system for testing the calculations used by Stokes was a sphere of unit
density falling in dry air. The sphere can be physically defined as having an area
(Eq.9-20)
where A p = sphere area projected on a plane normal to the fluid flow
Dp = sphere diameter
9-18
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(Eq.9-21)
and a mass jVf/, = — —
" 6
where Mp = mass of the sphere
Qp = true sphere density •
The discussion of streamline fluid flow around a body shows that a frictional
drag exists on the body defined for a sphere
(Eq.9-22)
where Fr = drag friction
C = drag coefficient
u = relative velocity of the particle in the fluid
Q = density of fluid.
The sphere will have a terminal velocity when the gravitational force acting on
the body rep-e
(Eq.9-23) Fg
where g L = local gravitational acceleration
Fg = gravitational force
and the frictional forces are equal: Fg = Fr. The net force on the body equals zero.
(Eq.9-24) FR\
n ° Net Force = 0
\Fr
The terminal velocity (u^) can be calculated:
J I 3eC
(Eq.9-25) ut =
A mathematical proof by Stokes showed that when inertial terms in streamline
fluid flow are negligible the frictional drag on a body submerged in the fluid can
be expressed as
(Eq.9-26) F{=3TTfJLU Dp
where
li = viscosity of the fluid.
9-19
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Substituting this expression into the original frictional drag equation the coeffi-
cient of drag (C) upon the body may be defined
(1) Fr = Ff
Q
(2)
(3) C =
QuDp
Using the above definition of drag coefficient in the equation for terminal
velocity and reducing all terms, the terminal velocity may be expressed:
(Eq.9-27) u
The conclusion that can be drawn from this complex proof is that a particle in a
fluid will have a terminal or settling velocity when the net forces acting upon it are
equal to zero. The velocity of the settling particle will be determined by the
viscosity of the fluid and be proportional to the size and mass of the particle. These
factors can make possible prediction of the physical properties proportional to the
size and mass of the particle.
Cunningham "Slip" Factor and Brownian Movement
The calculations in Stokes' Law hold for unit density particles between 3-100/«n in
size. A particle smaller than 3/«n has a higher terminal velocity than expected by
Stokes' Law. Particles in this range are approaching the mean free path length of
fluid molecules and experience less resistance than larger particles. A correction
factor developed experimentally was determined by Cunningham to calculate the
increased settling velocity of these particles.
The particles in this size range (< 3ju,m) are also subject to the effects of
Brownian movement. The particle experiences random motion from collision with
fluid molecules. This movement by collision is very important for correcting
gravitational settling velocity for particles >0.1/xm< 3/un. The effect of Brownian
movement upon particles <0.1/*m is much greater than gravitational settling
velocity. Brownian movement is a diffusion property analogous to the diffusion pro-
perties of a gas. Particles subject to Brownian movement exert a partial pressure in
the fluid proportional to their concentration.
Inertial Particle Sizing
The principles of isokinetic source sampling are founded upon the fluid dynamics
in the preceding discussion. An isokinetic sample taken from a gas stream does not
disturb the gas streamlines. It draws gas into the sampling nozzle with a force
equal to the forces propelling the gas up the stack. The distribution of particles
entering the sampling nozzle is theoretically the same as that existing in the stack.
Isokinetic sampling does not exert excess external forces upon the particles in the
9-20
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gas stream; therefore, an unbiased sample is taken. If the sampling were done over
isokinetically, external force would be exerted on particles in the gas. The gas
streamlines would be drawn closer together, bringing a larger percentage of small
particles into the sample. This analysis is based on particle inertia and fluid
resistance to particle movement relative to the fluid.
The inertial particle sizing devices operate to yield the best data when an
isokinetic sample enters the sample nozzle. The sample in the device contains a
valid representative sample of the particles distributed in the gas stream. Particles
of different size and mass are then separated by their inertia. The inertia of each
particle is proportional to its size and mass. This particle inertial force acts against
the resistive frictional forces of the surrounding fluid. The particle reaches its ter-
minal or settling velocity when these forces are equal. The inertial particle sizing
device creates a different fluid flow characteristic for various stages within the
device by causing the streamlines to come closer together. Particles that have
attained their settling velocity at a given stage in the sizing device do not follow the
gas streamlines and move out of the gas to impact on a collection stage. The
diagram illustrates the concept involved.
Gas steamline
Inlet
Orifice
Impaction collection plate
Figure 9-7. Inertial particle collector.
The particles have been separated based upon forces proportional to their size
and mass. The device used must be calibrated with particles of known size, shape,
and mass so the data for the unknown particles can be correlated. The most con-
venient method of calibration uses spherical particles of unit density dispersed in
dry air at standard temperature. The shape and size of the unknown particles is
not known directly; however, based on their behavior in the sizing device, an
"effect diameter" is determined which is related to the calibration spheres. Particles
9-21
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of unknown shape sized in an inertial sizing device that correlates particle size to
reference sphere calibration data are assigned an "aerodynamic diameter." This
term is used since the particles have been sized based upon the similarities
exhibited between the behavior of calibration spheres and the particle in a gas
stream. The aerodynamic diameter is related to the particle geometric diameter,
particle density, and shape in the expression:
(Eq.9-28) d _ Qp
aa — A
-------
velocity. These are usually used in the laboratory. Another laboratory technique is
the Bacho centrifugal separation. This device incorporates a radial gas stream of
known tangential velocity to separate particles by size and mass. It, like the elutria-
tion and sedimentation devices, is subject to the uncertainties and high repetition is
necessary in determining particle size from a sample collected out of the original
gas stream.
Microscopic analysis of particle sizing again requires high repetition to gain a
statistically representative evaluation of particle size. This technique requires that
those particles analyzed under the microscope do not agglomerate or overlap.
Data Analysis
A variety of methods exist for presenting particle size data. The method selected
for a particular situation will most likely be chosen based upon the type of sizing
system used, convenience, and intended use of the data. The most common
methods of presenting data are cumulative or frequency distribution curves. A fre-
quency distribution curve plots the number or weight of an incremental size range
against the average particle size of the given range. This is based upon the concept
that physical laws control the formation of particulates in any system. Particles
tend to form a preferential size for a given system which can be determined
empirically. Particle size frequency distributions, therefore, approximate a
probability relationship with a peak at a preferential size. The cumulative distribu-
tion is a plot of the fraction of the total number of particulates (or weight of par-
ticles) which have a diameter greater than or less than a given size plotted against
the size. This is actually an integrated frequency distribution curve.
Th. najority of inertial impactor particle size data uses the DJQ method of data
reduction. The particles on a given stage are assumed to have a diameter equal to
the calculated D$Q for that stage. Once the DJQ for each stage has been deter-
mined, the data can be simplified to yield a differential or cumulative plot of the
particle size sampled.
The cumulative plot of particle distribution is clear and easy to understand. The
weight of paniculate collected for each stage is presented as a percent of the total
paniculate catch. The data is then plotted as percent versus diameter yielding a
cumulative particle distribution curve. The method has a drawback in that a
weighing error is propagated throughout the data. Good calibration of the sizing
device greatly improves the data.
D. OPACITY MONITORING
Introduction
One of the more recent developments in the evaluation of source emissions has
been in the use of the transmissometer or opacity monitor. A knowledge of the
operation and type of information that may be obtained from these instruments is
very important for both the stack sampler and the stack test observer. Several con-
sulting firms are now using transmissometers during Method 5 tests to verify the
9-23
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stability of the source emissions during the testing period. Values of opacity may
even be used to determine the mass emission rate if a prior correlation exists
between the two for a given source. These techniques can be invaluable for check-
ing the validity of the Method 5 data itself.
The term "transmissometer" comes from the word "transmittance." When light
passes through a plume of smoke, some of it will be transmitted and will be able to
be observed on the other side of the plume. Some of the light, however, will be
scattered or absorbed by the particulate matter in the plume and will be lost to the
observer. If light is not able to penetrate through the plume at all, the plume is
said to be completely opaque, i.e., the "opacity" of the plume is 100%. Transmit-
tance and opacity can be related in the following manner:
% Transmittance = 100- % Opacity
Therefore, if a plume or object is 100% opaque, the transmittance of light through
it is zero. If it is not opaque at all (zero % opacity), the transmittance of light will
be 100%. Of course, a plume from a stationary source will generally not have
either zero or 100% opacity, but some intermediate value. In the New Source Per-
formance Standards, the opacity limits have been established for a number of sta-
tionary sources. The following sources are those required to continuously monitor
their emissions and maintain them within the given standard:
Opacity Limit
Fossil —Fuel Fired Steam
Generators 20%
Petroleum Refineries
(Catalytic Cracker) 30
Electric Arc Furnaces 15
Primary Copper, Lead, and
Zinc Smelters 20
Kraft Pulp Mills
(recovery furnace) 35
Continuous monitoring regulations for opacity were made to ensure that source
control equipment is properly operated and maintained at all times. EPA does not
consider the transmissometer to be an enforcement tool since the visible emissions
observer (EPA Reference Method 9) is still used to enforce the source opacity stan-
dards. However, data from the transmissometer may be used as evidence of the
opacity of an emission (see 42 FR 26205 5/23/77).
The Transmissometer
A transmissometer may be constructed in two ways, using either a single pass
system (Figure 9-8) or a double pass system (Figure 9-9).
9-24
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Collimating lens
Light source
Collimating lens
Detector
Rotary blower
Figure 9-8. Single-pass system.
Retro-reflector
Light
Beam splitte'r Detector)
Rotary blower
Figure 9-9. Double-pass system.
In the single pass system, a lamp simply projects a beam of light across the stack or
duct leading to the stack, and the amount of light transmitted through the flue gas
is sensed by a detector. Instruments designed in this configuration can be made
rather inexpensively; however, they often do not satisfy EPA criteria for system zero
and calibration checks. The double pass system shown in Figure 9-9 houses both the
light source and light detector in one unit. By reflecting the projected light from a
mirror on the opposite side of the stack, systems can be easily designed to check all
of the electronic circuitry, including the lamp and photodetector, as part of the
operating procedure. Most transmissometer systems include some type of air purg-
ing system or blower to keep the optical windows clean. In the case of positive
pressure stacks (Ps>0), the purging system should be efficient or the windows will
become dirty, leading to spuriously high readings.
9-25
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In contrast to ambient air continous monitoring instrumentation, EPA does not
"approve" specific manufacturer models. Since most stationary sources have unique
monitoring problems, EPA has established the "Performance Specification Test" as
a procedure for assuring that the instrument will operate properly once mounted in
a stack or duct. In addition, the transmissometer itself must satisfy several "design
specifications." Meeting the design specifications and passing the Performance
Specification Test constitute approval of the specific opacity monitoring installation.
Design Specifications
There are essentially seven design criteria that must be met by an opacity monitor.
These are as follows:
• Spectral Response —The system must project a beam of light
with the wavelength of maximum sensitivity lying between 500 and
600 nm. Also, no more than 10% of this peak response can be outside of
the range of 400 to 700 nm.
• Angle of Projection —The angle of the light cone emitted from the
system is limited to 5 degrees.
• Angle of View —The angle of the cone of observation of the photodetec-
tor assembly is limited to 5 degrees.
• Calibration Error —Using neutral density calibration filters, the instru-
ment is limited to an error of 3% opacity.
• Response Time —The time interval required to go from an opacity value
of zero to 95% of the value of a step change in opacity is li nited to 10
seconds.
• Sampling —The monitoring system is required to complete i. /n.' .imum
of one measuring cycle every 10 seconds and one data recording cycle
every 6 minutes.
• System Operation Check —The monitor system is to include a means of
checking the "active" elements of the system in the zero and calibration
procedures.
Before purchasing an opacity monitoring system, the instrument specifications
should be carefuly checked to see if the monitor satisfies these minimum
requirements. Failure to do so may mean that the monitor will not be accepted by
EPA for application as a continuous monitor of source emissions.
There are several reasons for establishing these design specifications. The most
important one is that there is no widely available independent method of checking
the opacity. Instead, it is assumed that if the system is designed correctly and can
be checked with filters for accuracy, it should be able to give correct flue gas
opacity readings. The rationale behind each of these specifications follows
9-26
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Spectral Response
The transmissometer is required to project a beam of light in the "photopic"
region —that region of the electromagnetic spectrum to which the human eye is
sensitive (Figure 9-10).
Photopic spectral response
100
Ultraviolet
Tungsten filament incandescent light
2500° K
1000 1500 2000 2500
Infrared
s~
visible Wavelength in nanometers
light
Figure 9-10. Photopic region.
There are three reasons for specifying this region:
• It was originally hoped to correlate the opacity readings of the
transmissometer with those of a visible emissions observer performing
EPA Method 9. If the transmissometer does project light in this region,
the readings usually will be comparable. However, background light con-
trast, acid aerosol formation, and other problems may cause the readings
by visible emissions observer to differ from the instrument readings.
• Water and carbon dioxide absorb light at wavelengths higher than
700 nm. If the transmissometer projected light in this region (as some
earlier systems did), any water vapor or carbon dioxide in the flue gas
would take away some of the light energy by absorption processes and a
high opacity reading would result (see absorption regions in Figure 9-10.
Since this would unduly penalize the operator (of a fossil fuel —fired
boiler, for example) filters or special optics are required to limit the
spectral response of the transmissometer.
• Small particles less than 0.5 micrometers in size will scatter light more
effectively if the light has a wavelength in the region of 550 nm (Figure 9-11).
9-27
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o.i
550 Nanometer wavelength light
I
/ 1000 Nanometer
wavelength light
0.2 0.3 0.4 0.5 1.0 2.0 3.0 4.0 5.0 10.0
Particle diameter in microns
Figure 9-11. Particle size effects.
Since, with the application of control devices to industrial sources, particles tend to
be small, light of short wavelength is required to detect them.
Angle of Projection
The ideal transmissometer would have a very thinly collimated, laser sharp beam
projected across the stack. When a beam diverges, particles outside of the
transmissometer path will absorb or scatter the light and light energy would be
effectively lost outside of the path. This would appear as higher opacity readings.
Because it is expensive to construct sharply collimated instruments, specifications
have been given to limit beam divergence to 5 degrees, as shown in Figure 9-12.
26 cm
Light source
Figure 9-12. Angle of projection.
The procedure for checking the angle of projection is to draw an arc with a 3 meter
radius, then measure the light intensity at 5 cm intervals for 26 cm on both sides of
the center line.
9-28
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Angle of View
The reason for specifying the angle of view of the detector assembly is similar to
that for the projection angle specification. In this case, if the angle of view was too
great, the detector might possibly pick up light outside of the transmissometer light
path. It would therefore "see" more light energy than it should and the
transmissometer readings would be lower than true (Figure 9-13).
26cm
Detector
(3m)
Figure 9-13. Angle of view.
The angle of view may be checked by using a small nondirectional light source to
see where, on an arc of 3 meter radius, a signal will appear. Generally, however,
the projection and detection angles are determined by the instrument manufac-
turer.
Calibration Error
Transmissometers are calibrated with neutral density filters corresponding to a
given percent opacity. The calibration error test is the closest possible procedure to
checking the accuracy of the instrument. Consequently, before an instrument is
placed on a duct or stack, the instrument response to calibration filters is required
to be within 3 percent of the predetermined filter values.
System Response Time Test
Since a transmissometer system is required by the regulations to measure opacity
every 10 seconds, a satisfactory system must be able to obtain a value for opacity
within this time period. An approvable transmissometer would have to reach 95%
of a calibration filter value within 10 seconds after it was slipped into the light
path to satisfy this design specification.
9-29
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Sampling Criteria
EPA regulations specify that an approvable transmissometer must be able to com-
plete a minimum of one measuring cycle every 10 seconds (40CFR60.13e). Also,
some provision must be made in the monitoring system to record an averaged
reading over a minimum of 24 data points every 6 minutes.
These specifications were established so that the opacity monitor would provide
information corresponding to (a) the behavior of the particulate control equipment
and (b) the data obtained by the visible emissions observer (EPA Method 9 requires
the reading of 24 plumes at 15 second intervals).
System Operation Check
The system operation check often has not been recognized by instrument vendors as
one of the design criteria for transmissometer systems. In fact, there is some ques-
tion whether several of the currently marketed opacity monitors could be approved
under this specification. In 40CFR60.13e3, it is stated:
"...procedures shall provide a system check of the analyzer
internal optical surfaces and all electronic circuitry including
the lamp and photodetector assembly."
This means that when calibrating or zeroing the instrument, the lamp or
photodetector used should be the same as that used in measuring the flue gas
opacity. For this reason, most single-pass opacity monitors would not be acceptable
under EPA design specifications, since a zero reading would not Jbe c nainable
unless the stack was shut down.
Installation Specifications
After a transmissometer that meets EPA design criteria has been selected by the
source operator, the instrument must be installed and checked for proper operation
on the source itself. There are several points that must be considered when install-
ing a transmissometer:
1. The transmissometer must be located across a section of duct or stack
that will provide a representative measurement of the actual flue gas
opacity.
2. The transmissometer must be downstream from the particulate control
equipment and as far away as possible from bends and obstructions.
3. The transmissometer located in a duct or stack following a bend must
be installed in the plane of the bend.
4. The transmissometer should be installed in an accessible location.
9-30
-------
5. The source operator may be required to demonstrate that the
monitor is obtaining representative opacity values at its installed
location.
It was intended that the transmissometer measure the actual flue gas opacity or
"an optical volume representative of the particulate matter flow through the duct
or stack." Figure 9-14 shows some of the problems in particulate matter flow
distribution which might occur in an exhaust system.
I Control
device I
Stack
Figure 9-14. Transmissometer siting.
Particulate matter may settle in ducts or stratify in the flue gas stream depend-
ing upon the construction of the exhaust system. In Figure 9-14 the "plane of the
bend" is that plane formed by the stack and the duct (in this case, the plane of the
paper). If one were to locate a transmissometer perpendicular to this plane, such as
at point A, a large portion of the particulate matter would not be seen by the inlet
breech. A transmissometer located at B would be in the plane of the bend and
would be sensing a cross-section of the total particulate flow. Location C would not
be appropriate for an opacity monitor because the monitor would not be in the
plane formed by the horizontal duct and the breeching duct. A monitor at location
C also would not satisfy criteria 1 or 2 since settling or particulate matter might
not provide a representative sample, in addition the location is close to two bends
in the exhaust system. Location D would be one of the best points for monitoring.
Here, the transmissometer would be most accessible and might be more carefully
maintained than if located at B. Location D follows the control device and does
not follow a bend. The only problem that might arise is the settling of particulate
matter in the duct and possible reentrainment to give nonrepresentative opacity
readings. An examination of the opacity profile over the width of the duct might
9-31
-------
be necessary to place the monitor at this point. Proper monitor siting is very impor-
tant to the source operator since an inappropriate choice for the location of a
monitor may cause measurement problems and entail expense, particularly if
re-siting is necessary.
The Performance Specification Test
Before an opacity monitoring system can be used for EPA reporting requirements,
it must undergo the Performance Specification Test. Since most sources differ in
operational design and construction, a given monitor might perform well at one
source but produce unacceptable data at another. Differences in location, par-
ticulate stratification, vibration, temperature, and other factors influence the
requirement that the opacity monitor be shown to operate at the location for which
it was intended. Design specifications are not sufficient for approval (in contrast to
ambient air monitors); the performance test must also be performed.
The Performance Specification Test for opacity monitors requires that the instru-
ment undergo a 1-week conditioning period and a 1-week operational test period.
In the conditioning period, the monitor is merely turned on and run in a normal
manner. This is essentially a "burn-in" period for the new instrument, and it is
hoped that problems that might be expected for a new device will appear during
this time. In the operational test period, the monitor is run for 1-week without any
corrective maintenance, repair, or replacement of parts other than that required as
normal operating procedure. During this period, 24-hour zero and calibration drift
characteristics are determined. If the instrument is poorly designed or is poorly
mounted, these problems should become evident from the drift data, and correc-
tive action would have to be taken. The only actual data necessary in the perfor-
mance test is that for zero and calibration drift. No relative accuracy test is taken
since there is no EPA reference method that gives an appropriate "true value" for
the opacity. (Since the EPA Method 9 visible emissions observer trains on a smoke
generator calibrated with a transmissometer, this method could not give an
independent opacity value.)
Data Reporting Requirements
After an opacity monitoring system has passed the Performance Specification Test,
it may be used to monitor source emissions. New sources required to monitor
opacity must report excess emissions on a quarterly basis. Since opacity standards
are based on the opacity of the plume at the stack exit, the in-stack
transmissometer data must be corrected to the stack exit pathlength using the rela-
tionship shown in Figure 9-15.
9-32
-------
L] = Emission outlet pathlength
Lg = Monitor pathlength
Oj = Emission opacity
O2 = Monitor opacity
LI
Figure 9-15. Relation betwen emission opacity and monitor opacity.
The transmissometer system must be able to record the average of at least 24
equally-spaced opacity readings taken over a 6 minute period. Any readings in
excess of the applicable standard (e.g., 20% opacity for a coal-fired boiler) must
be reported. Also, a report of equipment malfunctions or modifications must be
made. Although the recorded data does not have to be reported to EPA unless
excess emissions occurred, the data must be retained for a minimum of 2 years.
Opacity Monitor Applications
The uses of opacity monitors extend beyond merely satisfying EPA requirements for
installing such a system. Transmissometers have been used as combustion efficiency
indicators, broken bag detectors, and as process monitors during EPA Method 5
tests. Some of these specific applications are:
• Installation to satisfy EPA continuous opacity monitoring requirements,
• Installation for process performance data —maintenance and repair
indications, process improvement,
• Installation for control equipment operation —ESP tuning, broken bag
detection,
• Correlation with paniculate concentration,
• Maintenance of a continuous emissions record.
9-33
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The primary impetus for installing opacity monitors has been, of course, to
satisfy the EPA regulations contained in the New Source Performance Standards.
(Sources presently required to continuously monitor opacity were given in the
beginning of this chapter.) As previously stated, the application of monitoring
instrumentation to stationary sources is intended to provide a continuous check on
the operation of the air pollution control equipment. The source operator,
however, can use the continuous monitoring data to optimize the operation of his
process and control equipment. For example, in a fossil fuel-fired boiler, improper
combustion conditions may lead to the production of unburned carbon and
increased particulate matter. This might be caused by a blocked burner nozzle, a
fouled stoker, or an incorrect fuel-air mixture ratio. If not enough excess air is
added to the fuel in a coal or oil-fired boiler to give proper combustion, an opacity
monitor would be able to detect an increase in the flue gas opacity, and corrective
action could be taken (Note: a continuous CO monitor would also be useful in this
respect). The optimization of combustion efficiency, reduction of carbon build-up
on boiler tubes, and warning of process malfunctions are all benefits for the
source operation.
Opacity monitors have been used in bag house and electrostatic precipitator
applications. The breaking of a filter in a bag house will increase the opacity level
of an exhaust gas and could be detected by an inexpensive single-pass
transmissometer. Several companies currently market instruments for this purpose.
Transmissometers have also been used to "tune" the rapping systems of electrostatic
precipitators. By choosing the optimum rapping cycle of the precipitator collection
plates as a function of smoke opacity, precipitator operating costs can be reduced
and the emission standard met more easily. The application of transmissometers
after wet scrubbing control equipment has met with some difficulty Jbec?-ise of the
presence of entrained water (water droplets) in the flue gas stream. These water
droplets will scatter light and give a high opacity reading. To adequatel" rT"vitor
the particulate removal characteristics of a scrubber, the flue gas might have to be
reheated to evaporate the droplets. The utility of the transmissometer in monitor-
ing the proper operation of particulate control equipment was one of the primary
reasons for the establishment of the EPA continuous monitoring regulations. It was
felt that once a source had spent the money to put on a control device, there
should be some way that both the source operator and environmental agency per-
sonnel could be assured that the system would operate in a satisfactory monitor;
the transmissometer provides this assurance.
The extraction of a particulate sample from a flue gas stream for analysis has
been the method the Environmental Protection Agency has used to check com-
pliance to emission standards. It has been hoped for some time that the data
obtained froi i an opacity monitor could be correlated with that obtained from the
extractive method, EPA Method 5. This can be done, but only if two important
considerations are kept in mind: (a) the particle characteristics must remain the
same, and (b) the source operating characteristics must not change. Figures 9-16
and 9-17 show examples of correlations that have been made for a coal-fired boiler
and a cement kiln.
9-34
-------
s
2
c
8
500
400
300
200
100
0
0.15
0.10,
M,
'/I
s4
/&'/
M
/
9
i
•
g 0 0.05 0.10 0.15 0.20 0.25
ft
Optical density—single pass
Figure 9-16. Bituminous coal fired boiler emissions.
0 0.05 0.10 0.15 0.20 0.25
Optical density—single pass
Figure 9-17. Cement kiln emissions.
Here, the particulate concentration is given as a function of the optical density.
Optical density, O.D., is related to opacity in the following manner
(Eq.9-29)
O.D.=log10
1 - Opacity
This is a very useful expression since by considering the properties of particulate
scattering and absorption, a linear relationship between particulate concentration
and optical density results. The Beer-Bougert Law for the transmittance of light
through an aerosol states that
(Eq.9-30)
= e~naql or
-O) = e~naql
9-35
-------
where
T = transmittance
n = number concentration of particles
a = projected area of the particles
q = particle extinction coefficient
1= light path through the aerosol
O — opacity
If the logarithm is taken of both sides, we have
log (1 - O)= - 0.434naql
where 0.434 is conversion for
and 7
O.D. = log =Kcl
* (1-0)
where K is a constant describing the characteristics of the particle scattering and c
is the concentration (being proportional to n).
This states that O.D. = Kcl, or that the optical density is proportional to the par-
ticulate concentration. This is seen to be true from Figures 9-16 and 9-17. For this
relationship to hold, the particle characteristics must remain constant. Generally,
graphs like those given in Figures 9-16 and 9-17 are obtained by conducting a number
of EPA Method 5 tests along with an operating transmissometer. The correlation
between Method 5 and the transmissometer readings can be better than 10%.
Once such a relationship is made between opacity readings and particulate con-
centration, a stack tester could check his data in correspondence with those
readings. As more data becomes available from different sources under different
conditions, it is hoped that a library of such correlations can be made.
The basic use of an opacity monitoring system is for obtaining a continuous
record. The stack tester, fd the short term, can use transmissometer data to see if
soot-blowing occurred during the period of the test or if any other conditions
occurred that might give anomalous stack test results. For the long term, the con-
tinuous record can be used by the source operator to check the functioning of the
control system or to note long term improvement or degradation of performance.
Air pollution agency personnel can use such continuous data as evidence in com-
pliance cases although as yet this type of data cannot be used directly to enforce
standards. The continuous record, can however, tell the enforcement officer if
there is a his,.ory of noncompliance or if a control device is not operating properly.
The transmissometer is a useful tool both for source operators and air pollution
agency personnel. Through proper training and care of the instrument itself,
valuable process formation and emissions data can be obtained.
9-36
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Appendixes
A. Bibliography
B. Suggested References
C. Derivation of Equations
D. Concentration Correction Equations
E. International Metric System
F. Conversion Tables
•G. Constants and Useful Information
A-a
-------
APPENDIX A. BIBLIOGRAPHY
Air Pollution Training Institute. Source Sampling for Paniculate Emissions, Research Triangle
Park, NC; 1974.
Beer, Y. Theory of Errors. Reading, MA: Addison-Wesley Publishing Co.; 1958. .
Brenchley, D. L.; Turley, C. D.; Yarmac, R. F. Industrial Source Sampling. Ann Arbor, MI: Ann
Arbor Science Publishers Inc.; 1973.
Brooks, E. F.; Williams, R. L. Flow and Gas Sampling Manual. EPA 600/2-76-203,
July 1976.
Code of Federal Regulations—40CFR60.45; paragraphs e and f: Emission and Monitoring.
Code of Federal Regulations — 40CFR60.46; paragraphs a thru f: Test Methods and Procedures.
Cooper, H. B. H., Jr.; Rossano, A. T., Jr. Source Testing for Air Pollution Control. Wilton,
CT.: Environmental Research and Applications Inc.; 1971.
Devorkin, H.; Chass, R. L.; Fudurich, A. P.; Kanter, C. V. Source Testing Manual. Los Angeles,
CA; Los Angeles County Air Pollution Control District; 1965.
Federal Register —36FR24876; Standards of Performance for New Stationary Sources;
December 23, 1971.
Federal Register —41FR23060; Standards of Performance for New Stationary Sources — Amend-
ments to Reference Methods (Proposed Rules), June 8, 1976.
Federal Register—41FR44838; EPA Approval of Use of the Wet F Factor, Fw. October 12, 1976.
Federal Register —41FR51397; F and Fc Factors for Wood and Wood Bark (Wood Waste Boilers).
November 22, 1976.
Federal Register —42FR41754; Standards of Performance for New Stationary Sources — Revision to
Reference Method 1-8, August 18, 1977.
Harris, D. B. Procedures for Cascade Impactor Calibration and Operation in Process Streams.
EPA-600/2-77-004, January 1977.
Lapple, C. E. Fluid and Particle Mechanics. Newark, DE: University of Delaware; 1956.
Mitchell, W. J.; and Midgett, M. R. Field Reliability of the Orsat Analyzer, J. Air Pollution Con-
trol Assoc. 26 (5): 491; 1976.
Neulicht, R. M. Emission Correction Factor for Fossil Fuel-Fired Steam Generators. Stack
Sampling News 2 (8): 6-11 July 1973.
Perry, J. H.; Chilton, C. H. Chemical Engineering Handbook. 5th ed. New York: McGraw Hill
Book Company Inc.; 1973.
Resnick, R.; Holliday, D. Physics for Students of Science and Engineering. New York: John Wiley
and Sons, Inc.; 1960.
Shigehara, R. T.; Neulicht, R. M.; and Smith, W. S. A Method for Calculating Power Plant
Emissions. Stack Sampling News 1 (1): 5-9 July 1973.
Shigehara, R. T.; Neulicht, R. M. Derivation of Equations for Calculating Power Plant Emission
Rates, Q£ Based Method: Wet and Dry Measurements. Internal EPA Monograph, Research
Triangle Park, NC: Environmental Protection Agency, OAQPS, ESED, Emission Measurement
Branch; July 1976.
Shigehara, R. T.; Neulicht, R. M.; Smith, W. S.; and Peeler, J. W. Summary of F Factor
Methods for Determining Emissions. Unpublished Paper, EPA Emission Measurement Branch, July
1976.
Shigehara, R. T.; Neulicht, R. M.; Smith, W. S.; Peeler, J. W. Summary of F Factor Methods for
Determining Emissions from Combustion Sources. Source Evaluation Society News-
letter, Vol. I, No. 4, November 1976.
A-l
-------
Smith, F.; Wagoner, D.; Nelson, A. C. Guidelines for Development of a Quality Assurance Pro-
gram: Volume I —Determination of Stack Gas Velocity and Volumetric Flow Rate, (Type S Pilot
Tube). EPA 650/4-74-005-a, February 1974.
Smith, F.; Wagoner, D. Guidelines for Development of a Quality Assurance Program: Volume
IV —Determination of Paniculate Emissions from Stationary Sources. EPA 650/4-74-005-d, August
1974.
Steere, N. V. Handbook of Laboratory Safety. Cleveland, OH: The Chemical Rubber Co.; 1967.
Stern, A. C. Air Pollution; Third Edition, Volume III, Part C. New York: Academic Press; 1976.
Vollaro, R.F. The Effects of Impact Opening Misalignment on the Value of The Type S Pilot Tube
Coefficient. Unpublished Paper, Emission Measurements Branch, October 7, 1976.
Vollaro, R. F. Eslablishmenl of a Baseline Coefficienl Value for Properly Constructed Type S Pilot
Tubes. Unpublished Paper, EPA Emission Measurement Branch, April 20, 1977.
Vollaro, R. F. Recommended Procedure for Sample Traverses in Ducts Smaller lhan 12 Inches in
Diameler. United Stales Environmenlal Proleclion Agency. Unpublished paper, EPA Emission Measure-
menl Branch, January 3, 1977.
Vollaro, R.F. The Use of Type-S Pilol Tubes for ihe Measuremeni of Low Velocilies. Unpublished
Paper, EPA Emissions Measuremems Branch, January 19, 1977.
A-2
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APPENDIX B. SUGGESTED REFERENCE MATERIALS
AIChE.Stack Sampling and Monitoring-Advanced Seminar, AIchE, NY, NY; 1972.
Air Pollution Control Field Operations Manual. Publication No. 937. Washington, DC: U. S.
Public Health Service; 1962.
Air Pollution Source Testing Manual. Los Angeles, CA: Los Angeles County Air Pollution Con-
trol District; November, 1965.
Brenchly, D. L.; Turley, C. P.; Yarmac, R. F. Industrial Source Sampling, Ann Arbor, MI: Ann
Arbor Science; 1973.
Cooper, H. B. H. and Rossano, A. T. Source Testing for Air Pollution Control. Wilton, CT:
Environmental Science Services; 1971.
Danielson, A. J. Air Pollution Engineering Manual; AP40 —2nd ed. Research Triangle Park, NC:
EPA Office of Air Quality Planning and Standards; May, 1973.
Kirk—Othmer. Encyclopedia of Chemical Technology. New York: Interscience Division, John
Wiley and Sons, Inc.; 1970.
Perry, J. H. Chemical Engineering Handbook, 5th ed. New York: McGraw-Hill; 1970.
Report of the American Society of Mechanical Engineers. Fluid Meters — Their Theory and
Application. New York: ASME; 1959.
Steam, Its Generation and Use. New York: The Babcock and Wilcox Co.; 1963.
Steere, N. V., editor. Handbook of Laboratory Safety. Cleveland, OH: Chemical Rubber Company
(CRC) Press; 1§67.
Stern, A. C. Air Pollution, 3rd ed. Vols. I, II, III. New York: Academic Press; 1976.
Weast, R. editor. Handbook of Chemistry and Physics. 55th ed. Cleveland, OH: Chemical Rubber
Company (CRC) Press; 1973.
Williamson, S. Fundamentals of Air Pollution. Reading, MA: Addison-Wesley Publishing Co.;
1973.
Publications of the U.S. Environmental Protection Agency, Research Triangle Park, NC.
Guidelines for Development of a Quality Assurance Program: Volume IV — Determination of
Paniculate Emissions from Stationary Sources. EPA-650/4-74-005-d.
Procedures for Cascade Impaction Calibration and Operation in Process Streams.
EPA-600/2-77-004.
Paniculate Sizing Techniques for Control Device Evaluation. EPA-650/2-74-102-a.
Collection Efficiency Study of the Proposed Method 13 Sampling Train. EPA-600/2-75-052.
Rapid Method for Determining NOX Emissions in Flue Gases. EPA-600/2-75-052.
Collaborative Study of Method for the Determination of Paniculate Matter Emissions from Sta-
tionary Sources. EPA-650/4-74-029.
Collaborative Study of Method for Stack Gas Analysis and Determination of Moisture Fraction
with use of Method 5. EPA-650/4-73-026.
Collaborative Study of Method for Determination of Stack Gas: Velocity and Volumetric Flow
Rate in Conjunction with EPA Methods. EPA-650/4-74-033.
B-l
-------
Method for Obtaining Replicate Paniculate Samples from Stationary Sources. EPA-650/4-75-025.
Collaborative Study of Paniculate Emissions Measurements by EPA Methods 2, 3, and 5 using
Paired Paniculate Sampling Trains (municipal incinerators). EPA-600/4-76-014.
HP-65 Programmable Pocket Calculator Applied to Air Pollution Measurement Studies:
Stationary Sources. EPA-600/8-76-002.
HP-25 Programmable Pocket Calculator Applied to Air Pollution Measurement Studies:
Stationary Sources. EPA-600/7-77-058.
Flow and Gas Sampling Manual. EPA-600/2-76-023.
Continuous Measurement of Total Gas Flow Rate from Stationary Sources. EPA-650/2-75-020.
Quality Assurance Handbook for Air Pollution Measurement Systems —Vol. Ill — Stationary
Source Specific Methods. EPA-600/4-77-0276.
Periodicals
Journal of the Air Pollution Control Association
Environmental Science and Technology
Stack Sampling News
Pollution Engineering
Source Evaluation Society Newsletter
Environmental Reporter
B-2
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APPENDIX C. DERIVATION OF EQUATIONS
DERIVATION OF THE PITOT TUBE EQUATION
The pitot tube (Standard or Stausscheibe (S) Type) is used to measure the velocity
of a gas.. The pitot is actually a pressure sensing device that allows the determina-
tion of the gas stream velocity based upon the total system energy. Figure C-l
illustrates the fluid flow around a Standard Type pitot tube submerged in a gas stream.
I
\
k
pitot tube
Gas stream
T
Ap
Figure C-l. Fluid flow around a Standard Type pitot tube.
Applying Bernoulli's equation to points "a" and "b" we may describe the system:
Eq. C-l
where:
=Pa + 2/2 QV2
Pfj =/M// ram gas pressure at point b
Pa = free-stream gas pressure at point a — static pressure
Q — gas density
g = acceleration of gravity
y =some elevation above a reference level, which in this
case is negligible, therefore, y\=y^ = o
v =gas velocity
C-l
-------
Since y\ =y% = 0 Equation C-l may be written:
Eq. C-2 Pb
At point b, the gas molecules stagnate, giving up their kinetic energy. The gas
velocity at b is zero (i> = 0) and Equation C-2 becomes:
Eq. C-3
The kinetic energy of the gas molecules at b has been used to perform work on the
manometer fluid changing the height of the column (Ap). The knowledge that the
total energy in the system is conserved allows this derivation to proceed based on a
description of pressure terms in the system. The pressures in the system are
balanced when:
Eq. C-4 pb = pa + Q'g(&p)
where:
Q' = density of the manometer fluid
Ap = change in height of the manometer column
The full ram pressure is equal to the sum of the system static pressure and the
pressure of the manometer column. Rearranging terms in equations C-3 and C-4
we see:
Eq. C-5
and
Eq. C-6
which describes the calculation of the gas velocity of an ideal gas in a system free
of frictional energy losses.
The gas density may be described for a given gas of unknown density by using
the ideal gas law. The gas density is defined:
Eq. C-7 maSS
volume
We know from the ideal gas law that:
Eq. C-8 PSV= ^ RTS
C-2
-------
where:
Pj = absolute pressure
V= volume
m= mass of the gas
Ms= molecular weight of the gas
R = a constant
Ts = absolute gas temperature
Rearranging terms in equation C-8:
m MSPS
Then substituting in equations C-7 and C-6:
By using the following values in equation C-9 we can calculate a constant (Kp):
Eq. C-10 , o' „ _ = 62.428 Ib/ft3
' Hv\J
g= 32.174 ft /sec2
= 21.85
Ib - mole - °R
12 inches
2(62.428X32.174) (21.83)
12
= 85.486 ft/
J
v = K4
°R- inches
MSPS
The final term in our equation must account for the effect of friction and the
resultant turbulence in our system. A properly constructed standard pi tot tube will
not be measurably influenced by frictional effects. It may be assigned a coefficient
of friction (Cpst(j) of units. Any other pilot tube would have to be corrected for the
effects of turbulence about the tube. If we include Cpstc[ in our velocity equation
we have:
C-3
-------
Eq. C-ll
The gas velocity calculated using a standard pilot tube with Cp/stci) will be equal
to the velocity measured with an "S" type pitot tube if we know the Cp/s\ for the
"S" type pitot. This may be written:
KC
P^P(std)
f
-------
• Correcting the mass flow rate at the meter for the condensation of water
vapor
Eq. C-16 Qn=Qm
pm Ts
ps Tm \ ! ~ Bws
• The flow rate at the meter is given
•17 Qm = *m|/5
Derivation
Equations will be solved to give AH—the pressure differential across the orifice
meter for a given Ap in the stack.
From equation C-16
Eq. C-18 Qn=Qm|
pm
PsTm \ \-Bws
Substituting for Qjn from Equation C-17
Eq. C-19
P-m Ts 11 Bwm
Replacing Anvs for Q^ from Equation C-14
^ ^on , ,/
Eq. C-20 Anvs = Km\
4 5
Pm
*rn \ 1 Bws
Ts /\-Bwm\
— -
Tm\\-Bws)
Substituting An = and vs = KpCp
then squaring both sides of the equation
Eq. C-21
PSMJ \PmMm) P,2
C-5
-------
Solving for AH
Substituting Mm = Mrf(l - £„,,„) + l8Bwm and Ms = Md(l - Bws) + 18BWS
Eq. C-23
*KC2 l-B Ml-B + l8B] T
or
when assuming
.9244
^ = 85.49
DERIVATION OF THE ISOKINETIC VARIATION EQUATIONS
The term isokinetic sampling is defined as an equal or uniform sampling of gas in
motion. This is accomplished when the fluid streamlines of the stack gas are not
disturbed. The EPA Method 5 source sampling system is designed to extract, from
a stack, an isokinetic gas and particulate sample. A 100% isokinetic source sample
is taken when the gas velocity into the sampling nozzle (vn) is equal to the velocity
of the approaching gas stream (vs)
v-
n
Eq. C-24 % isokinetic variation = — X 100
The stack gas velocity (vs) is measured using a pitot tube to determine the stack
gas impact and static pressures. Bernoulli's theorem applied for the pitot tube and
solved for gas velocity gives the expression
-C-25
The velocity of the gas entering the source sampling nozzle is determined from
the principles in the equation of continuity. Solving the equation of continuity for
velocity at the nozzle, we may express the relationship
Eq. C-26 Vn=
C-6
-------
The nozzle cross-sectional area (An) is measured directly. The volumetric flow
rate of gas at nozzle conditions (Qn) is determined by correcting the dry gas
volume metered by the orifice back to stack conditions. The water vapor condensed
in the impingers must be included in this correction. Liquid water collected is con-
verted to vapor phase volume at stack conditions to obtain the volume sampled at
the nozzle.
The liquid water condensed (F/c) multiplied by the water density (gH o) gives
the mass of water collected in the impingers
Eq. C-27 (Vic) (Qn2o) = m
In the ideal gas law
Eq. C-28 PV= m RT
H^P
Solving the expression for volume
V=L mR
The volume at stack conditions is then
Ts mR
Vsw= Ts ~W
Ts (Vic)
Ps
= (Vlc)K
The gas volume metered at the orifice is corrected for orifice pressure and
temperature then added to V5W. This total is corrected to stack conditions over the
sampling time period to give
Eq. C-29 ^ [(VlJ W + (Vm/TmyPb + ~7)1
P« I 13.u I
0*=-^ 0 J
Then, since
%/= ^ xlOO
and
vs
C-7
-------
we have by substitution
Rearranging terms and including a correction for converting minutes to seconds
to cancel out dimensions, we obtain the expression in the Federal Register for
isokinetic variation
Eq. C-30
%/=100x
608AnVsPs
with the constant (K) equal to
K= 0.003454
mmHe — rn
- -
ml-°K
and
K = 0.002669
in. Hg-ft 3
- - -
ml-°R
(metric)
(English Units)
DERIVATION OF CONCENTRIC EQUAL AREAS OF A CIRCULAR DUCT
Traverse points are located at the centroid of an equal area in a circular duct.
A traverse point is thus a distance from the center of the duct — a radius of a
concentric equal area.
The distance or radius (TJ) for a traverse point (j) for any circular duct having
(N) equal areas may be determined in the following manner:
We know that TTT^ = area of a circle
C-8
-------
From the diagram we see:
Eq. C-31 7JT22 - TTr\2 = irr\ 2
which simplifies to:
Eq. C-32 ri2 =
* *• ct
Dividing these again into equal areas
Eq. C-33 r22 - n 2 = r22 - r22
Eq. C-34 / 9 9 9
M ^ - = * -
Solving Equations C-33 and C- 34and expressing in generalized form, the locus
of points TJ separating any area (j) into two equal areas is:
20
-I- T^ • 1
"I ^ ' 7 — 1
Eq.C-35 rj2=J—J—
Dividing the duct of radius R into N equal areas we find:
Eq. C-36
N
2
Substituting for ry_ i in Equation C-35
2^ 2
r-fc* -4- T •" - _-_^
« i ' -I "
7 ^
2 ,,-
7 N
2AT
C-9
-------
Solving Equation C-34 for r'j.
Eq. C-37 f =
2N
_/.
3 ^ 2N
The duct was divided into N equal areas each defined by a radius r\, r<£, r$, 7-4,
..... r~. r'j is the locus of points dividing each area into 2 equal areas. From the
diagram, N=4 and:
TTT
1
= 1/4
— =2/4
2
3
=3/4
-4/4
generalizing:
,.2 y
7 •*
Eq. C-38 — 4r - —
Substituting into equation C-31 and simplifying:
J
IN —-I
.. N
Eq. C-39 r'; = R\
3 1 27V
%—.
= RU 3
2N
C-10
-------
where: j= any locus of points dividing an equal area into 2 equal areas
(i.e., traverse point at the centroid of an equal area) and N= number
of equal areas.
The percent of the duct diameter (P) (the distance from the inside wall of the duct
to a traverse point) is obtained for r'j by the following method.
(Eq.C-40)
a. / ., x. \ From the diagram
2r'j + 2z = Diameter D
D-2rl:
z=
b. Percent of diameter (P) = — X100
1 ' D
Substituting from equations C-40 and C-39 and simplifying
(D-2r!:)100
P= +D
2
50(D-2r'j)
D
P =
D
where P = percent of diameter from inside duct wall to radius rj
N= total number of equal areas
j = specific area for which the location of points is calculated
j= 1,2,3,4...from the center of duct outward.
DERIVATION OF THE EQUIVALENT DIAMETER EQUATION
FOR ANY SHAPE DUCT
The equivalent diameter (ED) for a duct is also defined as the hydraulic duct
diameter (Hp). The hydraulic radius (Rfj) for a duct transporting fluids is defined
as the cross-sectional area of that part of the channel that is filled with fluid
divided by the length of the wetted perimeter.
A stack gas will completely fill a duct and the entire duct perimeter will be
wetted. Considering this situation for a circular duct we find
C-ll
-------
(Eq.C-41)
(d\2 d2
RH=^L±=L
ird d 4d
This illustrates that the hydraulic radius of a circular duct is one-fourth the duct
diameter. The equivalent or hydraulic diameter for a noncircular pipe is 4 times
the hydraulic radius
(Eq.C-42) 4RH = HD = ED
The equivalent diameter for the rectangular duct illustrated would be:
(Eq.C-43)
L
W
= 2
2L + 2W L+W
which is the equation given in the Federal Register: this equation can be used for
determining the equivalent diameter of any duct. Method I guidelines can then be
applied.
DERIVATION OF THE EQUATIONS FOR
MEASURING WATER VAPOR
Nomenclature
Bws = proportion by volume of water vapor in a duct-gas at the sampling-point.
B(v = proportion by volume of water vapor in a gas-mixture for saturated condi-
tions.
ea = water vapor pressure in a gas-mixture passing a wet-and dry-bulb ther-
mometer assembly.
es =
water vapor pressure in a gas-mixture at the sampling point.
e£ = water vapor pressure in a gas-mixture for saturated conditions and dry-bulb
temperature at the sampling-point.
e/m = water vapor pressure for saturated conditions and meter temperature.
ef/ = water vapor pressure at saturated conditions and wet-bulb temperature.
Mw = molecular weight of water (mass per mole)
mwc=mass of water collected in the condenser.
Pa= absolute pressure at the wet-and dry-bulb temperature assembly.
Ps = absolute pressure of a duct-gas at the sampling point.
C-12
-------
Pm = absolute pressure at the meter.
Pmjx = absolute pressure of a gas-mixture.
R= universal gas constant.
Tm = absolute temperature at the meter.
ldry( °C)= dry-bulb temperature in °C.
tdry(°F)== dry-bulb temperature in °F.
twet(°C) = drybull) temperature in °C.
twet(°F)= wet-bulb temperature in °F.
Vm= volume of gas passed through the meter at meter conditions.
Vwc = volume of water vapor that condensed at the condenser referred to meter
conditions.
Vws = volume of water vapor extracted from the duct referred to meter conditions.
VWm = volume of water vapor passed through the meter referred to meter condi-
tions.
0O = relative humidity of the duct-gas.
Water Vapor Pressure and Proportion of Water Vapor
by Volume in a Gas-Mixture
Saturated Conditions
Water vapor pressure
Water vapor pressures for saturated conditions are given in Figure C-2.
Proportion of water vapor
The proportion (by volume) of water vapor in a gas-mixture for saturated condi-
tions given by
e'
(Eq.C-44) B'w= (1)
"mix
Non-Saturated Conditions
Wet- and dry-bulb method
a. Proportion of water vapor in a duct-gas.
If it is expected that the proportion by volume of water vapor in a duct-gas will be
less than 15%, or that the dewpoint is less than 126°F, the wet- and dry-bulb
temperature method may be used to determine water vapor pressure. Care must be
taken that the flow past the wet bulb is 12 to 30 feet per second, and that
temperature has reached equilibrium. It is essential that the dry-bulb, as well as
the wet-bulb, be completely immersed in the gas, and that the cloth wick around
the wet-bulb be clean, saturated with water, and tied tightly at all times. For the
most accurate results, the two thermometers should be similar.
C-13
-------
Wet Bulb
Temp.
Deg. F.
20
10
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
0
.0126
.0222
.0376
.0376
.0631
.1025
.1647
.2478
.3626
.5218
.7392
1.032
1.422
1.932
2.596
3.446
4.525
5.881
7.569
9.652
12.20
15.29
10.01
23.47
28.75
35.00
42.31
50.84
60.72
72.13
85.22
100.2
117.2
136.4
158.2
182.6
209.8
240.3
274.1
311.6
353.0
398.6
448.6
503.6
1
.0119
.0209
.0359
.0398
.0660
.1080
.1716
.2576
.3764
.5407
.7648
1.066
1.467
1.991
2.672
3.543
4.647
6.034
7.759
9.885
12.48
15.63
19.42
23.96
29.33
35.68
43.11
51.76
61.79
74.36
86.63
101.8
119.0
138.5
160.5
185.2
212.7
243.5
277.7
315.5
357.4
403.4
453.9
509.3
2
.0112
.0199
.0339
.0417
.0696
.1127
.1803
.2677
.3906
.5601
.7912
1.102
1.513
2.052
2.749
3.642
4.772
6.190
7.952
10.12
12.77
15.98
19.84
24.46
29.92
36.37
43.92
52.70
62.88
74.61
88.06
103.4
120.8
140.6
162.8
187.8
215.6
246.8
281.3
319.5
361.8
408.2
459.2
515.1
3
.0106
.0187
.0324
.0463
.0728
.1186
.1878
.2782
.4052
.5802
.8183
1.138
1.561
2.114
2.829
3.744
4.900
6.330
8.150
10.36
13.07
16.34
20.27
24.97
30.52
37.07
44.74
53.65
63.98
75.88
89.51
105.0
122.7
142.7
165.2
190.4
218.6
250.1
284.9
323.5
366.2
413.1
464.6
521.0
4
.0100
.0176
.0306
.0441
.0768
.1248
.1955
.2891
.4203
.6009
.8462
1.175
1.610
2.178
2.911
3.848
5.031
6.513
8.351
10.61
13.37
16.70
20.70
25.48
31.13
37.78
45.57
54.62
65.10
77.17
90.97
106.7
124.6
144.8
167.6
193.1
221.6
253.4
288.6
327.6
370.7
418.1
470.0
526.9
5
.0095
.0168
.0289
.0489
.0810
.1302
.2035
.3004
.4359
.6222
.8750
1.213
1.660
2.243
2.995
3.954
5.165
6.680
8.557
10.86
13.67
17.07
21.14
26.00
31.75
38.50
46.41
55.60
66.23
78.46
92.45
108.4
126.5
147.0
170.0
195.8
224.6
256.7
292.3
331.7
375.2
423.1
475.5
532.9
6
.0089
.0158
.0275
.0517
.0846
.1370
.2118
.3120
.4520
.6442
.9046
1.253
1.712
2.310
3.081
4.063
5.302
6.850
8.767
11.12
13.98
17.44
21.50
26.53
32.38
39.24
47.37
56.60
67.38
79.78
93.96
110.1
128.4
149.2
172.5
198.5
227.7
260.1
296.1
335.9
379.8
428.1
481.0
538.9
7
.0084
.0150
.0250
.0541
.0892
.1429
.2203
.3240
.4586
.6669
.9352
1.293
1.765
2.379
3.169
4.174
5.442
7.024
, 8.981
11.38
14.30
17.82
22.05
27.07
33.02
39.99
48.14
57.61
68.54
81.11
95.49
111.8
130.4
151.4
175.0
201.3
230.8
263.6
299.9
340.1
384.4
433.1
486.2
545.0
8
.0080
.0142
.0247
.0571
.0932
.1502
.2292
.3364
.4858
.6903
.9666
1.335
1.819
2.449
3.259
4.289
5.585
7.202
9.200
11.65
14.62
18.21
22.52
27.62
33.67
40.75
49.03
58.63
69.72
82.46
97.03
113.6
132.4
153.6
177.5
204.1
233.9
267.1
303.8
344.4
389.1
438.2
492.2
551.1
9
.0075
.0134
.0233
.0598
.0982
.1567
.2382
.3493
.5035
.7144
.9989
1.378
1.875
2.521
3.351
4.406
5.732
7.384
9.424
11.92
14.96
18.61
22.99
28.18
34.33
41.52
49.93
59.67
70.92
83.83
98.61
115.4
134.4
155.9
180.0
206.9
237.1
270.6
307.7
348.7
393.8
443.4
497.9
557.3
Figure C-2. Vapor pressures of water at saturation (inches of Mercury)
C-14
-------
The water vapor pressure existing in the gas-mixture passing the assembly may
be determined from equations below,
(Eq.C-45) *g = e><- <
2800-l.3twet(oF)
(The Carrier Equation)
If there is no leakage of gas, or condensation, upstream from the thermometer
assembly the proportion (by volume) of water vapor in the duct at the sampling-
point and in the assembly are equal. Therefore:
^
(Eq.C-46) Bm= _f
Pa
b. To determine the water vapor pressure in a duct-gas for saturated conditions,
es
substitute — for Bws.
PS
p _
(Eq.C-47) es~
•B
Condenser Method
a. Proportion of water vapor in a duct-gas.
When the water vapor content of the duct -gas is expected to be above 15%, the
condenser method may be used. Care must be taken that no water vapor is con-
densed before the condenser. A filter is necessary to ensure that no paniculate mat-
ter will foul the condenser, meter, or pump.
The gas leaving the condenser is saturated with water vapor, and if conditions are
maintained so that the gas remains saturated as it passes through the meter, equa-
tion C-44 is applicable. The volume of water vapor that passed through the meter,
referred to meter temperature and pressure, is:
wm vm
The total volume of water vapor in the sample extracted from the duct at the
sampling-point, referred to meter temperature and pressure, is
-------
The proportion by volume of water existing in the duct at the sampling-point is
R ws
(Eq.C-50) aw=
Vwc +
Substituting for VW5 (see Equation C-49):
(Eq.C-51) Bm= —
Water vapor pressure in a duct-gas. Having calculated Bws from equation C-51,
water vapor pressure existing in the duct at the sampling point may be determined
by
(Eq. C-52) es =BWSPS
DERIVATION OF RELATIVE HUMIDITY OF A DUCT-GAS
Definition
Relative humidity of the duct-gas at a sampling point is defined as:
(Eq. C-53)
es
C-16
-------
DETERMINATION OF RELATIVE HUMIDITY
Use of equations and table
es, may be determined by measurement using the condenser method, .or the wet-
and dry-bulb temperature technique; e's may be found from saturation tables
(Figure C-2). Equation C-57 may then be applied.
Use of a psychrometric chart
Psychrometric charts similar to Figures C-4 and C-5 may be used to determine
relative humidity. Directions are shown in Figure C-3. Care should be taken that
the pressure of the duct-gas is not so different from that for which the chart is
designed to introduce significant error.
ft
>,
(H
"O
-o
&
1
u
§
I
e
o
= 100%
t
Dry-bulb temperature
*dry
Figure C-3. Determination of relative humidity by using a psychrometric chart.
C-17
-------
n
00
s
n
n
ET
3
n
o
n
o
o
o
s
a.
g"
3
n'
§
O
Relative ,
Humidity(%
20 25 30
35
40
45 50 55 60 65 70 75 80 85 90 95
100
Dry-bulb temperature (°F)
-------
f
3
s-
1
S'
n
S-
S
9 B.
P
r^
o-
I
ft
(O
(O
a
ere
( ) denotes volume fraction water vapor.
Density factor
Humid volume—cu. ft.
300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500
Dry-bulb temperature (°F)
-------
DETERMINATION OF PROPORTION OF WATER VAPOR
S
Since Bws = — the proportion (by volume) of water vapor in the duct-gas may be
"s
found by substituting s(e$ ) for ep (see Equation C-5/)
se's
(Eq. C-54)
"WS
where s = water vapor pressure in the duct-gas at the sampling point.
e's = water vapor pressure in the duct-gas for saturated conditions
and dry-bulb temperature at the sampling point.
p = absolute pressure of the duct-gas at the sampling point.
DEW-POINT
Definition
The temperature at which a mixture of gases can exist saturated with vapor is
called the dew-point. Below the dew-point, condensations of water vapor occurs.
Determination of Dew-Point
1. Using saturation tables.
The dew-point may be determined by use of water vapor pressure tables for
saturation conditions as shown in Figure C-2. Knowing the existing water
vapor pressure, the temperature at which the value exists can be interpolated
from the table.
= 100%
DEW POINT J(
Mrfry
Figure C-6. Determination of Dew-Point by Use of a Psychrometric Chart.
C-20
-------
n
f
sr
3
H
>*•
n
n
m
O.
I
s,
ft)
30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180
Dry bulb temperature, °F
-------
Water vapor percent by volume
u
|H
4*t
2
8,
£
"3
Q
ISO
190
200
210
90100110120130 140 150 160
200
Wet bulb temperature °F
Figure C-8. High-temperature psychrometric chart for air-water vapor mixtures
at 1 atm (29.921 in. Hg.).
C-22
-------
2. Using a psychrometric chart.
The dew-point may be determined from a psychrometric chart similar to
Figures C-4 and C-5. Directions are shown in Figure C-6. Care should be
taken that the pressure of the gas-mixture is not so different from that for
which the chart is designed that significant error will be introduced.
DERIVATION OF THE EQUATION FOR MOLECULAR WEIGHT
OF STACK GAS
Introduction
• Calculations involved in source sampling require knowledge of the molecular
weight of a stack gas.
• Stack gas is almost always a mixture of gases.
• The apparent molecular weight of the gas mixture is a function of the com-
position of the mixture.
• Stack gas containing significant quantities of gaseous effluents other than ox-
ygen, nitrogen, carbon dioxide, and water vapor should be analyzed chemical-
ly for composition and apparent molecular weight determined from this data.
Calculation of Apparent Molecular Weight of Gas Mixture
This derivation assumes the major components of the gases from a hydrocarbon
combustion source to be oxygen, nitrogen, carbon dioxide, water vapor, and car-
bon monoxide.
The Ideal Gas Laws
1 . Boyle's Law states that at constant temperature the volume of a given mass
of a perfect gas of a given composition varies inversely with the absolute
pressure.
2. Charles' Law states that at constant volume the absolute pressure of a given
mass of a perfect gas of a given composition varies directly as the absolute
temperature.
3. Combining these relationships into an equation, it may be stated
(Eq. C-55) PV=
m
where P- absolute pressure
T = absolute temperature
V = volume of a gas
M = molecular weight of a gas (mass /mole)
m = massLof the gas
C-23
-------
4. Equation C-55 satisfies Dalton's Law of partial pressures when
xR ^mixture
(Eq. C-56^ pxvmixture =
where Px= partial pressure of a gas component in a mixture of
nonreacting gases.
^mixture = volume of the gas mixture
mx — mass of a gas component
R = universal gas constant (in appropriate units)
^mixture = absolute temperature of the gas mixture
Mx = molecular weight (mass /mole) of a gas component
°x ^mixture mx
Note - is constant only if - remains constant.
^mixture Mx
Proportion by volume of a component in a gas mixture
1. Equation C-55 states that for a gas mixture
(Eq.C-57)
2. Applying this relationship in equation C-56 and removing the common term
it may be seen that the partial pressure of a given gas component is directly
related to the mole fraction of that component in the gas mixture
mx
(Eq. C-58)
mmix
3. At constant temperature and pressure equation C-55 may be written
. CM) 2 =
M RT
C-24
-------
4. Rearranging Equations C-56 and C-57 as Equation C-59 and substituting in
Equation C-62
(Eq. C-60)
p*
Pmix
A
5. Letting the proportion by volume (B^ equal . Equation C-60 may
now be expressed vmix
(Eq. C-61) Bx = —^-
6. Equation C-61 gives the proportion by volume of a gas component as a func-
tion of partial pressure, which (from Dalton's Law) is directly related to the
mole fraction.
The apparent molecular weight of a gas mixture may now be derived using the
relationship of partial pressure to mole fraction.
1. Rewriting Equation C-56
(Eq. C-62) MXPX Vmix = mxR Tmix
2. Dalton's Law tells us that Equation C-62 is actually
(Eq. C-63) VmixLPxMx = R Tm,xXmx
3. Emx = mm{x and from Equation C-56
/T- f* CA\
(Eq. C-64) ™mix= - —
K1
mix
4. Substituting for *Lmx and solving for Mmjx in Equation C-64 becomes
(Eq. C-65)
p
5. Since * = Bx, Equation C-65 can be
Pmtx
(Eq. C-66) Mmix = LBXMX
C-25
-------
Stack Gas Analysis Using Orsat Analyzer.
1. Orsat operates at constant proportion by volume of H%O vapor
2. Yield volume data on dry basis (volume related to mole fraction and partial
pressure)
3. Apparent molecular weight must include H^O vapor component of stack gas
4. Stack gas moisture content may be obtained as described in moisture content
section
5. Actual apparent molecular weight may be calculated by
Mmix = ZBXMX(I ~ Bws) + BwsMH20
XMX — sum of dry mole fractions
Bws = proportion by volume of H^O in stack gas
MHO = molecular weight o
C-26
-------
APPENDIX D. CONCENTRATION CORRECTION EQUATIONS
Introduction
After a value for the concentration of a pollutant in a flue gas stream is obtained
by a reference method test, it is often necessary to correct the value to some stan-
dard set of conditions, which is done to compare the data from one source to that
of another. Different stack temperatures and different amounts of excess air would
make a comparison of the actual concentrations almost meaningless. Therefore,
terms such as SCFM for "Standard Cubic Feet per Minute" instead of ACFM ("Ac-
tual Cubic Feet per Minute") and cs (corr. 50% EA) instead of cs are generally
used when reporting data. Note that in reporting data in units of the standard, E
(lbs./106 Btu heat input), the pollutant concentration is expressed as pounds per
dry standard cubic foot and an excess air correction is included in the F factor
equation (Chapter 7). In this section, derivations for correcting a concentration to
standard conditions, 50% excess air, 12% CO2, and 6% O2 will be given.
Concentration Corrected to Standard Conditions
A concentration is expressed as weight per volume or lb./ft.3.
(Eq.D-1) - Cj = y
The volume of gas passing through the nozzle will be at stack pressure and
temperature. After going through the Method 5 train and meter, that temperature
and pressure will change. A reference or standard set of conditions must be used,
therefore, to make the data meaningful. The ideal gas law is used in these con-
siderations (see Chapter 2).
Therefore, since
(Eq.D-2) PV = nRT
and
pstack conditions Pstd
For the same number of moles of gas, the volume that that number would occupy
at standard conditions would be as follows
dividing,
Vcorr = std = Tstd Ps
(Eq.D-3) Vs nR TS TS Pstd
PS
D-l
-------
i, Tstd ps
or Pcorr = Vs-^r-=
1s pstd
and cs (at standard conditions) = = — —-—2td_
vcorr vs Tstd ps
Tstd PS
EPA has defined 7^ = 460 + 68°F and Pj^ = 29.92 inches Hg (42 FR 41754,
August 18, 1977).
To report a concentration on a dry basis, the volume must be expressed as if all
of the water had been removed. The value of Bws must be known in this case.
(Eq.D-4) Vdry = Vwet - VwetBws
Vdry ~ Vwet(l ~ BWS)
m m
or c
Vdry Vwet (1
Cs(wet)
(1-BWS)
Combining these two corrections,
pstd
(Eq.D-5) cs (corrected to Ibs. /DSCF) =
(1-BWS) Tstd Ps
Excess Air
Several types of concentration corrections have been devised based on the combus-
tion characteristics of fossil fuels. Excess air is defined as that percentage of air
added in excess of that required to just combust a given amount of fuel. Normally,
to achieve efficient fuel combustion, more air is needed than the stoichiometric
amount, i.e., one carbon atom to two oxygen molecules. (Details of these combus-
tion conditions are given in APTI course #427.)
D-2
-------
Depending on the amount of excess air, different concentrations of CO2 and
oxygen in the stack gas will result, as shown in Figure D-l.
g
et
N
o
•w
Og (Bituminous coals)
10 to SO 40 50 60 70
Percent excess air
90 100
Figure D-l. Concentrations of CO2 and D£ in stack by amount of excess air.
Since the concentration of the pollutants produced in the source could be
reduced by adding more excess air, (i.e., if cs =m/V, if V is increased with m con-
stant, c5 would decrease), it has been found necessary in some cases to correct to a
given excess air condition. A value of 50% excess air has been chosen as a
reference condition since at one time many boilers operated at this condition. Note
also that if such a correction is made, that it will account for dilution caused by air
leaking in at the preheater or other duct work.
The expression for % excess air, as given in EPA Method 3, is
(Eq.D-6)
%EA =
%O2-Q.5% CO
0.264% N2-(%O2-Q.5% CO)
100
To derive this expression, gas volumes associated with the combustion of the fuel
must be considered.
(Eq.D-7)
^Theoretical^ vTotal~ VEA
stoichiometric volume
of air required to
consume an amount of
fuel
total volume
of air used
\
volume of air
in excess of
^Theoretical
D-3
-------
Since air is composed of 79% N2 and 21% O2, if there was complete
stoichiometric combustion, all of the oxygen would be consumed and
(Eq.D-8) VNz = 0.79 VThe0reticai
V Theoretical ~ TTnq
Remember, however, that when excess air is added, the oxygen contained in that
volume will not react since there will be no carbon left to consume it,
or
(Eq.D-9) y frrmm'ninir) = n 2\
V I \ f\ I t K lil/lMltilvlrHlf'J \J , £j 1
The problem of incomplete combustion must also be considered in this calcula-
tion. Carbon monoxide is produced if burning conditions are not adequate.
C+O2 - *- CO + 1/2 O2
The amount of oxygen remaining in the flue gas must then be corrected for in-
complete combustion since for each two molecules of CO produced, one molecule
of oxygen will result,
(Eq.D-10) 0.5 VcQ=VQj (incomplete combustion)
Equation D-8 must be modified so that
0.b Vco
(Looking at this another way, 1/2 of an oxygen molecule is released for each CO
molecule and would contribute to VQ~ (remaining).) Therefore, from Equation
D-ll
F02-0.5 VCO
(Eq.D-12) VEA = - — -
Substituting Equations D-8 and D-12 into Equation D-7, we have
(Eq.D-13) V 'Theoretical VT- VEA
VN2 (^02-°-5 VCO)
^Theoretical^ Q 70 ~ 0~2~1
D-4
-------
Percent excess air is defined as that percent of air in excess of that needed for
complete combustion, or
(Eq.D-14) %EA= - - — - x 100
^Theoretical
Therefore:
F02-0.5VCO
(Eq.D-15) %EA = — - — - x 100
0.79 21
F0_-0.5 Vco
%EA = 22 ™ x 100
0.266 VN-V0 + Q.b Vco
divide numerator and denominator by VT
%EA= — X100
0.266 VN/VT-V02/VT+0.5 VCO/VT
%02-0.5%CO
0.266 % N2 - % O2 + 0.5 % CO
Concentration Corrected to 50% Excess Air
To correct a pollutant concentration to 50% Excess Air
^Theoretical
where AF is the volume that would have to be added or subtracted to give 50%
EA.
AV=VEA±0.5 VTheor
and
FEA VT=
D-5
-------
where FEA is the proportion of V-p that would have to be changed to give 50%
EA.
VTheor+ VEA - VEA+0.bVTheor
Fj? A = - — - ---
* VT vTheor+ VEA
1.5 Vrheor
divide numerator and denominator by Vfheor to &*
1.5 150
(Eq.D-17) FEA =
I+VEA ioo+% EA
Therefore, since
m
VT
cs (corrected 50% EA) =
VTFEA VT I 150
%EA
/17 Tk 10^ / 1 /100+%E/A
(Eq.D-18) c5 (corr)=cs - — ^ -
\ 150 /
It should be noted that there is a method of calculating cs corrected to 50% EA
without first calculating % EA.
Starting from
,* T^IQ^ ,r
(Eq.D-19) FEA = - - - = 1 -
v-p
(vEA-o.s (VT-VEA)}
\ VT )
-i-l
D-6
-------
from Equations D-8 and D-12, we have
1.5(T02-0.5
= 1-
VT
1.5%02-0.75%CO-0.133%
—-
and
(Eq.D-20)
cs (corr) =
m
= Cc
1.5% 02-0.75% CO-0.133% N2
21
It should be noted that equations D-18 and D-19 are not equivalent and cannot
be made equivalent. They do, however, give the same answers using values
characteristic of combustion sources. Note that Equation D-14 for %EA becomes
discontinuous as the flue gas approaches a composition corresponding to that of air
(neglecting CO). Equation D-18 also becomes discontinuous under certain condi-
tions (e.g., %02 = 7.7%, %JV2 = 79,% C0 = 0).
Correcting Concentration to 12% CO2
The derivations for correcting a concentration to 12% CO2 or 6% O2 are
similar to that for the 50% Excess Air Correction. For a correction to 12% CO2 in
the flue gas.
(Eq.D-21)
= 0.12
or
Fco2 VT=VT±
where &V = amount of air added or subtracted to give 12% CO2 and
fraction by which Vactual w°uld have to be reduced or increased to do this.
Substituting,
tne
(Eq.D-22)
FC02 VT
= 0.12
D-7
-------
and
%C02
(Eq-D-23) FC02=—7^—
L £*
m cs
Correcting Concentration to 6%
Instead of correcting a concentration to 12% C?2, a correction may be made using
just the oxygen concentration. The oxygen correction is somewhat more com-
plicated than that for CO2 since dilution air" will contain oxygen.
The derivation begins with
(Eq.D-24) 0
where V is the amount of air added or subtracted to give 6% O2 in the corrected
volume. Note that the term ±0.21 A.V is due to the oxygen contained in air.
For Fo being the fractional amount, VT must be changed,
(Eq.D-25) F02 VT=FT-AV
and substituting into Equation D-22
V0 +0.21 VT-0.21 VT±0.21 AV
= .06
0 -0.21 VT+0.21F0 VT
— =.06
and
21~%02
(Eq.D-26) F0 =0.21 VT- Vo =
D-8
-------
and similarly to the previous derivations
(Eq.D-27)
Note that if a correction to 3% O2 was needed
(Eq.D-28)
18
02) =
21 - % 02
D-9
-------
APPENDIX E. INTERNATIONAL METRIC SYSTEM
Systeme International d'Unites (SI Units)
Base Units of the International Metric System (SI)
Quantity
Length
Mass
Time
Temperature
Electric current
Luminous intensity
Amount of substance
Name of the Unit
meter
kilogram
second
kelvin
ampere
candela
mole
Symbol
m
kg
s
K
A
cd
mol
Recommended Decimal Multiples and Submultiples and the Corresponding
Prefixes and Names
Factor
1012
109
106
103
102
10
10-1
10-2
lO'9
Prefix
tera
mega
kilo
hecto
deca
deci
centi
milli
micro
nano
pico
femto
atto
Symbol Meaning
T One trillion times
G One billion times
M One million times
k One thousand times
h One hundred times
da Ten times
d One tenth of
c One hundredth of
m One thousandth of
/i One millionth of
n One billionth of
p One trillionth of
f One quadrillionth of
a One quintillionth of
E-l
-------
Some Derived Units of the International Metric System (SI)
Quantity
Frequency
Force
Pressure
Energy
Power
Quantity of electricity
Electrical potential or
electromotive force
Electric resistance
Electric conductance
Electric capacitance
Magnetic flux
Magnetic flux density
Inductance
Luminous flux
Illumination
Name of the unit
hertz
newton
pascal
joule
watt
coulomb
volt
ohm
siemens
farad
weber
tesla
henry
lumen
lux
Symbol
Hz
N
Pa
J
W
C
V
0
S
F
Wb
T
H
An
&
Equivalence
1 Hz=l s-1
1 N = 1 kg-m/s
1 Pa=l N/m
1 J=l N-m
1 W=l J/s
1 C = l A-s
1 V = 1 W/A
1 0=1 V/A
1 S=A/V
1 F=l C/V
1 Wb = 1 V-s
1 T=l Wb/m
1 H=l Wb/A
1 ftn = 1 cd-sr
1 &=1 &/m
Some Suggested SI Units for Air Pollution Control
Volume flow: Liters per second (1/s)
Velocity (gas flow): Meters per second (m/s)
Air to cloth ratio: Millimeters per second (mm/s)
Pressure: Kilopascals (kPa)
E-2
-------
APPENDIX F. CONVERSION TABLES
Conversion Between Different Units
Listed below are quantities of the English and engineering systems of units that are
commonly found in the literature on air pollution. Our intention is to present
them so that their equivalent in the MKS system of units can be found quickly.
Quantities that are listed in each horizontal line are equivalent. The quantity in
the middle column indicates the simplest definition or a useful equivalent of the
respective quantity in the first column.
1 acre
1 Angstrom (A)
1 atmosphere (atm)
1 bar (b)
1 barrel (bbl)
1 boiler horsepower
1 British Thermal Unit
(Btu)
1 Btu/hour
1 calorie (cal)
1 centimeter of mercury
(cmHg) -
1 cubic foot, U.S.A. (cu ft)
1 dyne (dyn)
1 erg
1 foot, U.S.A. (ft)
1 foot per minute (ft/min)
1 gallon, U.S.A. (gal)
1/640 mi2
10'8 cm
1.013 X 106 dyn/cm2
106 dyn/cm2
42 gal, U.S.A.
3.35 X 104 Btu/hour
252 cal
1.93 X 106 erg/sec
4.184 X 10'7 erg
1.333 X 104 dyn/cm2
2.832 X 104 cm3
1 g-cm/sec2
1 g-cm2/sec2
30.48 cm
1.829 X 10'2 km/hr
3.785 X 103 cm3
4.047 X 103 m2
10-10 m
1.013 X 105 N/m2
105 N/m2
0.159 m3
9.810 X 103 W
1.054X 103J
0.293 W
4.184J
1.333 X 103 N/m2
2.832 X 10'2 m3
10'5 N
10-7 J
0.3048 m
5.080 X 10'3 m/sec
3.785 X 10'3 m3
F-l
-------
Conversion Factors
Capacity, Energy, Force, Heat
Multiply By
Btu 0.252
Btu 9.48X10-4
Btu/min 3.927X10'4
Btu/min 2.928X10'4
Btu/min 0.02356
Btu/min 0.01757
Btu/min 10'3
Horsepower (boiler) 33,479
Horsepower (boiler) 9.803
Horsepower-hours 0.7457
Kilowatts 56.92
Kilowatts 1.341
Kilowatt-hours 3415
Kilowatt-hours 1.341
Megawatts 1360
Pound/hr steam 0.454
Heat Transfer Coefficient
Multiply By
Btu/(hr)(ft2)(°F) 0.001355
1.929X106
0.0005669
To Obtain
Kilogram-calories
Watt-seconds (Joules)
Horsepower-hours
Kilowatt-hours
Horsepower
Kilowatts
Pound/hour steam
Btu/hour
Kilowatts
Kilowatt-hours
Btu/minute
Horsepower
Btu
Horsepower-hours
Kilogram/hour steam
Kilogram/hour
To Obtain
Cal/(sec)(cm2)(0C)
Btu/(sec)(in2)(0F)
Watts/(cm2)(°C)
F-2
-------
Flow
Multiply
Cubic feet/minute
Cubic feet/second
Cubic feet/second
Cubic meter/second
Cubic meter/second
Gallons/year
Gallons/minute
Liters/minute
Liters/minute
Million gallons/day
Million gallons/day
Million gallons/day
By
0.1247
0.646317
448.831
22.8
8.32X109
10.37x10-6
2.228X10-3
5.886X10-4
4.403x10-3
1.54723
0.044
695
Pounds of water/minute 2.679 X 10
To Obtain
Gallons/second
Million gallons/day
Gallons/minute
Million gallons/day
Gallons/year
Cubic meters/day
Cubic feet/second
Cubic feet/second
Gallons/second
Cubic feet/second
Cubic meters/second
Gallons/minute
Cubic feet second
Length, Area, Volume
Multiply
Acres
Acres
Acres
Barrels-oil
Barrels-oil
Centimeters
By
43,560
4047
1.562X10-3
0.156
42
0.3937
To Obtain
Square feet
Square meters
Square miles
Cubic meters
Gallons-oil
Inches
Cubic feet
Cubic feet
Cubic feet
Cubic feet
Cubic feet
Cubic feet
Cubic meters
Cubic meters
Feet
Feet
2.832X104
1728
0.02832
0.03704
7.48052
28.2
35.31
264.2
30.48
0.3048
Cubic centimeters
Cubic inches
Cubic meters
Cubic yards
Gallons
Liters
Cubic feet
Gallons
Centimeters
Meters
F-3
-------
Length, Area, Volume cont'd
Multiply
Gallons
Gallons
Gallons, Imperial
Gallons water
Liters
Meters
Meters
Square feet
Square feet
Square meters
Square meters
Square miles
By
0.1337
3.785x10-3
1.20095
8.3453
0.2642
3.281
39.37
2.296x10-5
0.09290
2.471x10-4
10.76
640
To Obtain
Cubic feet
Cubic meters
U.S. gallons
Pounds of water
Gallons
Feet
Inches
Acres
Square meters
Acres
Square feet
Acres
Mass, Pressure, Temperature, Concentration
Multiply
Atmospheres
Atmospheres
Atmospheres
Feet of water
Inches of Hg
Inches of water
By
29.92
33.90
14.70
0.02947
0.04335
62.378
0.03342
13.60
1.133
0.4912
70.727
345.32
0.03609
5.1981
25.38
To Obtain
Inches of mercury
Feet of water
Pounds/Square inch
Atmospheres
Pounds/square inch
Pounds/square foot
Atmospheres
Inches of water
Feet of water
Pounds/square inch
Pounds/square foot
Kilograms/square meter
Pounds/square inch
Pounds/square foot
Kilograms/square meter
F-4
-------
jVIass, Pressure, Temperature, Concentration cont'd
Multiply
Kilograms/square
centimeter
Kilograms/square meter
Kilograms
Pounds
Pounds of water
Pounds of water
Pounds/square inch
Pounds/square inch
Pounds/square inch
Pounds/square inch
Temp.(°C)+17.78
Temp.(°F)-32
By
0.9678
14.22
0.00142
0.20482
0.00328
0.1
2.2046
453.5924
0.01602
0.1198
0.06804
2.307
70.31
2.036
1.8
0.555
To Obtain
Atmospheres
Pounds/square foot
Pounds/square inch
Pounds/square foot
Feet of water
Grams/cm2
Pounds
Grams
Cubic feet
Gallons
Atmospheres
Feet of water
Grams/cm2
Inches of mercury
Temperature(°F)
Temperature(°C)
Degrees Kelvin = degrees Centigrade +273.16
Degrees Rankin = degrees Fahrenheit+ 459.69
Tons (metric)
Tons (short)
Tons (short)
2205
0.89287
0.9975
Pounds
Tons (long)
Tons (metric)
Thermal Conductivity
Multiply
Btu/(hr)(ft2)(°F/ft)
By
0.00413
12
To Obtain
Cal/(sec)(cm2X0C/cm)
Btu/(hr)(ft2)(°F/in)
F-5
-------
Viscosity
Multiply
Poise
Centipoise
Stoke
By
1.0
1.0
100
0.000672
0.0000209
2.42
1.0
0.155
0.001076
density
(gm/cm^)
To Obtain
Gm/cm sec
Dyne sec/cm^
Centipoise
Pounds/foot second
Pound/second square foot
Pound/foot hour
Square centimeter/second
Squared inch/second
Squared foot/second
Poise
Density
Multiply
Grams per cc
Gram-moles of Ideal Gas
at 0°C and 760mm Hg.
Pounds per cubic inch
Pound-moles of Ideal Gas
at 0°C and 760 mm Hg.
Grams/liter
Grams/liter
Grams/liter
Parts/million
Parts/million
By
62.428
0.03613
8.345
22.4140
1728
27.68
359.05
58.417
8.345
0.062427
0.0584
8.345
To Obtain
Pounds/cubic feet
Pounds/cubic inch
Pounds/U.S. gallon
Liters
Pounds/cubic feet
Grams/cubic centimeter
Cubic feet
Grains/gallons
Pounds/1000 gallons
Pounds/cubic feet
Grains/U.S. gallons
Pounds/million gallons
F-6
-------
Conversion from ppm to g/m^ at STP
pstd = ! atm
(Eq. F-l.)
S2 ill x
g-mo/e
x
/293.15°*:\
\273.150J!:/
F-7
-------
APPENDIX G. CONSTANTS AND USEFUL INFORMATION
Energy Equivalences of Various Fuels
Approximate Values
Bituminous coal - 22 X 106 Btu/ton
Anthracite coal - 26 X 106 Btu/ton
Lignite coal - 16 X 106
Residual oil -147,000 Btu/gal
Distillate oil 140,000 Btu/gal
Natural gas 1,000 Btu/ft3
1 Ib of water evaporated from and at 212 °F equals:
0.2844 Kilowatt-hours
0.3814 Horsepower-hours
970.2 Btu
1 cubic ft air weighs 34.11 gm.
Miscellaneous Physical Constants
Avogadro's Number
Gas-Law Constant R
6.0228X1023
1.987
1.987
82.06
10.731
0.7302
Molecules/gm mole
Cal/(gm mole)(°K)
Btu/(lbmole)(°R)
(cm3)(atm)/(gm mole)( °K)
(ft3)(lb)(in.2)/(lb mole)(°R)
(ft3)(atm)/(lb
Weight of Og, Ng and Air
1 Pound
1 Ton
1 SCF Gas
Oxygen
Nitrogen
Oxygen
Nitrogen
Oxygen
Nitrogen
Pounds
1.0
2000.0
0.08281
0.07245
Tons
0.0005
1.0
0.00004141
0.00003623
SCF Gas
12.08
24,160
27,605
1.0
G-l
-------
Typical Coal Combustion Emissions Data
Particulate mass loading, after precipitator
before precipitator
Mass loading spatial variation at duct
cross-section
Particle size, after precipitator
before precipitator
Extreme particle size range
Flue gas velocity
Flue gas temperature
Dew point
Moisture content of gas
Static pressure at sample ports
Turbulent Flow fluctuations
Traversing distance across duct from port
0.03-3.0 gm/cu meter
0.2-12 gm/cu meter
±50%
Mass median diameter = 5/«n
95% <25/«n (by mass)
0.01-300 pan
Average: 15-20 m/sec.
Range: 10-40 m/sec.
Typical: 140-165 °C
Range: 130-205 °C
Acid: 105-130°C
Water: <60°C
5-10% by volume
Range: 15 cm positive to
35 cm negative water pressure
30-120 cycles per minute
Typical: 2-5 meters
Range: 1.5-10 meters
Typical Oil Combustion Emissions Data
Particulate mass loading, uncontrolled
Mass loading variation with time
Mass loading variation during soot blowing
Particle size
Flue gas temperature range
Flow conditions
Typical: 0.06-0.2 gm/cu meter
Range: 0.015-1.0 gm/cu meter
As much as 10-fold increase
over typical
About 4-fold increase over
typical
Typical: 0.01-1.0/un
Range: < 0.01-40 fim
120-165°C
Similar to those for coal
combustion
G-2
-------
TECHNICAL REPORT DATA
(Please rcaJ fiiwiietions on the reverse before coin/
1. REPORT NO
EPA-450/2-79-006
2.
Source Sampling for Participate Pollutants
Student Manual
6. PERFORMING ORGANIZATION CODE
3. RECIPIENT'S ACCESSION-NO.
5. R£PORTDATE. -_..
December 1979
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
G. J. Aldina ami J. A. Jahnke
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Northrop Services, Inc.
P. 0. Box 12313
Research Triangle Park, NC 27709
10. PROGRAM ELEMENT NO.
B18A2C
11. CONTRACT/GRANT NO.
68-02-2374
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Manpower and Technical Information Branch
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Student Manual
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
EPA Project Officer for this manual is R. E. Townsend, EPA, ERC, NC (MD-17)
16. ABSTRACT
This manual is used in conjunction with Course #450, "Source Sampling for Particulate
Pollutants", as designed and presented by the EPA Air Pollution Training Institute
(APTI). The manual supplements the course lecture material, presenting detailed
discussions in an introductory manner on the following topics:
Basic Definitions for Source Sampling
Basic Concepts of Gases
The EPA Method 5 Sampling Train
The EPA Method 5 Source Test
Calibration Procedures
Source Sampling Calculations
Report Writing
Error Analysis
F-factor Methods
Particle Sizing
Opacity Monitoring
Derivations are given for many of the basic source sampling equations. The manual,
when used with the student workbook, EPA-450/2-79-007, during the lecture and
laboratory sessions of Course #450, provides comprehensive instruction in the
performance of EPA reference method 5.
(NOTE: There is also an Instructor's manual that may be used in conducting the
training course - - EPA-450/2-80-003, APTI Course-#450, Source Sampling for
Particulate Pollutants - Instructor's Guide.)
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
COSATI Field/Group
Measurement
Collection
Air Pollution
Gas Sampling
Dust
Calibrating
Filtered Particle Sampling
Stack Sampling
Particle Measurement
14B
14D
18. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (ThisReport)
Unclassified
21. NO. OF PAGES
202
20. SECURITY C
uncTa"-
assifie
'This page)
22. PRICE
EPA Form 2220-1 (9-73)
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