Draft 11-10-77
DEVELOPMENT, OBSERVATION, AND EVALUATION
OF PERFORMANCE TESTS
AT
ASPHALT CONCRETE PLANTS
Prepared by:
James W. Peeler
Entropy Environmentalists, Inc.
P. 0. 12291
Research Triangle Park, N. C.
Prepared for:
The Division of Stationary Source Enforcement
U.S. Environmental Protection Agency
NOTICE
This draft document has not been
formally reviewed by EPA. It is
being circulated for review and
comment on its technical accuracy.
-------
Draft 11-10-77
DEVELOPMENT, OBSERVATION, AND EVALUATION
OF PERFORMANCE TESTS
AT
ASPHALT CONCRETE PLANTS
Prepared by:
James W. Peeler
Entropy Environmentalists, Inc.
P. 0. 12291
Research Triangle Park, N. C.
Prepared for:
The Division of Stationary Source Enforcement
U.S. Environmental Protection Agency
NOTICE
This draft document has not been
formally reviewed by EPA. It is
being circulated for review and
comment on its technical accuracy.
-------
TABLE OF CONTENTS
I Introduction 1
II Process and Control System Description 3
2.1 Basic Process Description 3
2.2 Emission Points 6
2.3 Air Pollution Control Equipment 7
III Emission Control Regulations 15
3.1 Federal Regulations 15
3.2 State Regulations 16
IV Process Parameters Affect Potential Emissions 19
4.1 Process Variables and Their Relation to 19
Dust Loading
4.2 Normal Range of Process Parameters 23
Plant Capacity
4.3 Process Modifications 26
V Control System Parameters Affecting Emissions 29
5.1 Control System Parameters 29
5.2 Control System Modifications 33
VI Representative Conditions - Test Protocol -
Pretest Meeting 36
6.1 Determination of Representative Conditions 36
6.2 Test Protocol 38
6.3 Pretest Meeting 39
VII Emission Test Methods and Acceptable Alternatives 41
7.1 Emission Test Methods 42
7.2 Commonly Encountered Sampling Problems 45
and Acceptable Alternatives
VIII Monitoring Process and Control System Parameters 51
8.1 Monitoring the Process 51
8.2 Monitoring Control System Parameters 55
8.3 Additional System Parameters 62
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IX Visible Emission Observations 66
X Review and Evaluation of Performance test
Reports 68
10.1 Review of Test Reports 68
10.2 Checking Test Data 70
Appendix A - NSPS Regulations
Appendix B - EPA Test Methods
Appendix C - Blank Data Forms
Appendix D - Isokinetic Sampling in Non-Parallel
Flow Systems - Cyclonic Flow
11
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LIST OF FIGURES
2-1 Typical Pulse-Jet Configuration 10
2-2 Venturi Scrubber 12
2-3 Low-Energy Scrubber System 14
7-1 Air-Water Vapor Psychrometric Chart 48
8-1 Process Flow Diagram 53
8-2 Nomograph For Estimating Flue Gas 56
Composition - Excess Air Or Type Of Fuel
8-3 Measurement Of Static Pressure Drop 57
8-4 Measurement Of Static Pressure Drop 57
8-5 Flow Meter Installation 60
8-6 Pressure Gage Installation 60
10-1 Air-Water Vapor Psychrometric Chart 73
10-2 Moisture From The Ambient Air 75
10-3 Determining Moisture In The Flue Gas From 75
Combustion of Fuel
111
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LIST OF TABLES
2-1 Primary And Secondary Control 8
Devices Used In The Asphalt
Hot-Mix Industry
3-1 Summary Of State Regulations 17
4-1 Mix Compositions 24
iv
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Chapter I
INTRODUCTION
The Standards of Performance for New Stationary Source
(NSPS), promulgated by the U.S. Environmental Protection Agency
(EPA) under Section 111 of the Clean Air Act, require performance
tests to be conducted on any new or modified sources affected
by the standards. A determination of compliaace with the stand-
ards is made based on the written report of the test results
submitted to the EPA Regional Office or State Air Pollution Con-
trol Agency delegated NSPS authority.
This manual presents practical information for use by State
and Federal field enforcement personnel in planning, observing,
and evaluating performance tests at hot-mix asphalt concrete
plantsi The source sampling manual for hot-mix aspahlt concrete
plants ia one of a series of technical manuals being prepared
by the Division of Stationary Source Enforcement, EPA, which
address the individual performance testing needs and problems
of the various source categories for which NSPS have been promul-
gated. These manuals are designed to provide source-specific
background information, guidelines, test procedures, and solutions
to special emission testing problems to aid agency personnel in
ensuring that valid and representative results are obtained
from performance tests at new stationary sources.
The source-specific material presented in this manual re-
garding techniques and procedures for evaluating performance
tests at hot-mix plants should be used in conjunction with the
general procedures outlined in the DSSE Compliance Testing Manual
series entitled "Development, Observation, and Evaluation or
Performance Tests." This manual is also intended to be sup-
plemental to the DSSE Stationary Source Enforcement Manual entitled,
"Inspection Manual for Enforcement of New Source Performance
2
Standards - Asphalt Concrete Plants."
Development, Observation, and Evaluation of Performance Tests,
currently being prepared by the DSSE,U.S.EPA.
Inspection Manual for Enforcement of New Source Performance
Standards-Asphalt Concrete Plants, U.S. EPA, 340/1-76-003, March 1976.
-------
For more in-depth information on the EPA reference test methods and
their proper application, the EPA publication "Quality Assurance
Handbook for Air Pollution Measurement Systems, Volume Ill-
Stationary Source Specific Methods " should be consulted.
This manual deals with conventional hot-mix asphalt concrete
plants. Drum-mix plants will be covered in a later manual, as
information about this relatively new process becomes available.
Although the manual primarily applies to performance tests at
sources subject-to NSPS it also has general application to existing
plants subject to state regulations. .However, due to the diversity
of state regulations and tests.procedures, and for the sake of'
brevity, this manual will not cover all the problems related to
testing existing sources. ., ..>• '-.=•;. ; r r'^-
Chapter II-provides a brief-description of the hot-mix asphalt
concrete manufacturing process and':its. operation. Chapter III
summarizes the NSPS regulations and gives- examples of typical -.
state regulations..Chapters IV and.V describe process and control
system parameters which affect:emissions. Suggested agency pre-
paration and procedures.for selection,of representative.conditions
for performance tests are described in Chapter VI. Emission ; •,
testing methods and solutions to-special sampling- problems are-
provided in Chapter.: VI11... Procedures for monitoring .process..and *
control system.parameters during .performance tests are; included-.,
in Chapter VIII. Concurrent visible emission observations are ';
discussed in Chapter IX. Chapter, X contains procedures for
review and evaluation of the test report. Recommendations for...
future surveillance of plant operation are included in Chapter,XI.
Applicable NSPS regulations and EPA test methods are included in
Appendices A and B. Data forms for use by agency observers are
included in Appendix C. -
uality Assurance Handbook for Air Pollution Measurement Systems;
plume III - Stationary Source Specific Methods,currently
being prepared by the Environmental Monitoring and Support
Laboratory, U.S. EPA.
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Chapter II
PROCESS AND CONTROL SYSTEM DESCRIPTION
2.1 Basic Process Description
Asphalt concrete is basically a mixture of crushed stone,
sand, and mineral dust which is dried, heated, and then coated
with hot asphalt cement. The principal use for asphalt concrete
is surfacing of roads and parking lots and other paving operations.
For a more complete description of the hot-mix process, the reader
should consult "Inspection Manual for Enforcement of New Source
A:
2
Performance Standards - Asphalt Concrete Plants" or the
"Asphalt Plant Manual."
2.1.1 Raw Materials
The raw materials used in the production of asphalt concrete
are asphalt cement, various sizes and types of aggregate, and
fuel for the dryer.
Aggregate. Asphalt mixes may be produced from a wide range
of aggregate combinations. Each mix has particular characteris-
tics which are suited to specific applications. Mixtures are
generally classified according to the relative amount of coarse
aggregate, fine aggregate, and mineral filler.
Coarse Aggregate - crushed stone, slag, or gravel (material
retained on No.8-mesh sieve) 3
Inspection Manual for Enforcement of New Source Performance
Standards - EPA 341/1/76-003, March, 1976
2
Asphalt Plant Manual, The Asphalt Institute Manual Series, No. 3,
fourth edition, December, 1974.
No. 8-mesh sieve - (2.38 mm or .094 in.)
-------
Fine Aggregate - natural sand or finely crushed stone
or gravel (material passing No. 8-
mesh seive)
Mineral Filler - (mineral dust) - very finely ground
particles of crushed stone, limestone
Portland cement, or other non-plastic
mineral materials.(material passing No.
200-mesh sieve) 4
Asphalt Cement. Asphalt cement, a residual by-product
of the petroleum cracking process, makes up from 3% to 8% of the
product weight. Normally a solid at ambient tmeperatures, the
cement must be heated to 135-177°C (275-350°F) to be used as a
liquid. Cut-back asphalt, used in the production of "cold
patch" asphalt mixes, is produced by adding mineral oils or
solvent to regular asphalt cement. ' :
Fuel. The rotary dryer is usually gas or oil-fired. Natural
gas and No. 2 fuel oil are the most commonly used fuels. LPG
and heavy fuel oils (no. 5, no. 6) are sometimes used as alternative
fuels. , .
2.1.2 Process Description
Asphalt concrete is produced in both batch plants and
continuous plants. The two types of plants are similar in most
respects, differing mainly in the feed mechanisms to the mixer
and in the mixer itself. Drum-mix plants will be" covered in a
supplemental manual currently being prepared.
The Batch Process. The process begins as raw aggregate
is transferred from stockpiles to the cold bins. There are
usually three or four cold bins, each containing a different
grade of aggregate. The aggregate is metered from the cold bins
onto a conveyor and is then transferred either directly or by
means of a bucket elevator to the rotary dryer. The dryer is an
inclined revolving cylinder usually ranging from .9-3 meters
(3 to 10 feet) in diameter and from 4.6-12.2 meters (15 to 40 feet)
No. 200 mesh sieve - (.074 mm or .0029 in.)
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long. The dryer performs two functions: 1)removal of moisture
from the aggregate, and 2) heating of the aggregate to mixture
temperature, 121-177°C (250-350°F). The conventional rotary
dryer is either gas or oil fired with the burner being located
at the aggregate exit; thus, the air and combustion gases flow
counter-current to the aggregate flow. The term "direct-fired"
is often used to describe conventional dryers, since the aggregate
is in direct contact with the burner flame and combustion gases.
The rotating cylinder is equipped with longitudinal channels
called "flights" which lift the aggregate and drop it in veils
through the hot gases to facilitate maximum heat transfer, the
slope of the dryer, its rotational speed, diameter, length,
and number of flights control the length of time required for
the aggregate to pass through the dryer.
The aggregate leaving the dryer is transported by a hot
bucket elevator to a set of vibrating screens at the top of the
mixing tower. The aggregate is classified by size into several
grades by the screens and is then stored in hot bins. Aggregate
from each of the hot bins is weighed in the weigh hopper to obtain
the desired size distribution for the mixture. The weigh hopper
discharges to the mixer or "pugmill" where the aggregate is mixed
dry for about 30 seconds, after which asphalt cement is pumped in
from heated storage tanks to complete the mixture. When the
asphalt and aggregate are thoroughly mixed, the product is loaded
into trucks or held in heated storage silos.
The Continuous Plant. The major difference between the
continuous plant and the batch plant is seen in the operation of
the mixer or "pugmill". In the continuous plant, aggregate from
the hot bins is metered and transported by a set of feeder-con-
veyors to the mixer. Hot asphalt cement is also metered to the
inlet end of the mixer. Flow through the mixer is continuous and
retention time is controlled by an adjustable dam at the outlet
end of the mixer. The completed product flows to a holding hopper
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from which the trucks are loaded. Some plants have heated
storage facilities for holding the product.
2.1.3 Typical Operations
Plant capacities range from 90 to 800 tons per hour; a
180 tons per hour plant is considered average. Currently, batch
plants are much more common than continuous plants. Typical
plants produce 5,000 pound batches although some newer plants
produce 8,000 pound batches.
There are an increasing number of portable asphalt plants,
(plants which can be temporarily located at maj or paving sites).
Currently, portable plants constitute approximately 151 of- the
total.
Various degrees of automation are encountered at asphalt
plants: Some plants are completely automated so that all op-
erations are controlled from a central control center. Batch
programmers are often employed to control the weighing and mixing
operations. Older plants typically have fewer automatic or remote
controls and are operated manually. The use of automatic controls
generally provides smoother plant operation and a more consistent
product.
2.2 Emission Points
The rotary dryer is the major source of particulate emissions
at hot-mix asphalt plants. The exhaust gases from the dryer are
almost always ducted to a primary control device. Most plants use
either a cyclone or multicyclone as the primary collector. The
dust collected in the cyclone is returned to the hot bucket elevator
or weigh hopper to serve as additional mineral filler in the mix-
ture. In order to comply with air pollution regulations, the
effluent gases from the primary collector are ducted to a seco ,
air cleaning device with a relatively high collection efficiency.
' Personal communication, Fred Kloiber, Director,Engineering §
Operations, National Asphalt Pavement Assoc., Riverdale, Md.
-------
The hot elevator, vibrating screens, hot bins, weigh hopper
and mixer are also sources of particulate emissions at hot-mix
asphalt plants. Particulate emitted directly to the atmosphere
from these sources is referred to as fugitive dust. The particulate
emissions from these sources are controlled by enclosing the
sources with a scavenger ducting system and conveying the dust-
laden gas to a control device. Usually the scavenger system is
connected to the dryer exhaust system before the primary collector.
A few plants employ a separate control device for the scavenger
system. It should be emphasized that the particulate and opacity
standards apply to emissions from all control systems.
2.3 Air Pollution Control Equipment
An asphalt plant equipped only with a primary collection
device (cyclone) will typically release 5.0 to 7.5 kg of par-
ticulate per metric ton of asphalt produced, (10-15 Ibs of
1
particulate/ton of asphalt). A plant so equipped operating
at 150 metric tons per hour (165 tons/hr) would emit 748 to
1122 kg (1650-2475 Ibs) of particulate per hour of operation.
To comply with the concentration standard, 90 mg/dscm, prescribed
by the New Source Performance Standards, such asphalt plants must
reduce potential emissions by approximately 99.6%. Relatively high
efficiency collectors are required to achieve the required degree
of control. The best systems for emission reduction, taking into
account the cost, are considered to be well-designed, well operated,
g
and well maintained baghouses and venturi scrubbers. In addition
to baghouses and venturi scrubbers, multiple low engery scrubbers
in series are often used to control particulate emissions from
the asphalt industry. Table 2-1 shows the types and frequency of
application of various control devices used at hot-mix asphalt
plants.
Background Information for New Source Performance Standards,
U.S. EPA (APTD-135Za) Vol. 1, p.9.
8Ibid., (APTD-1352c), Vol. 3, p.13.
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Table 2-1
Primary and Secondary Control Devices
Used in the Asphalt Hot-Mix Industry
TYPES OF EQUIPMENT PERCENT OF INDUSTRY
Primary Collectors
Settling Chambers 4
Cyclones 58
Multicylones 35
Other 3
Secondary Collectors
Baghouses 40
Venturi Scrubbers 16
Low Energy Scrubbers 40
Other 4
2.3.1 Primary Collection Devices
Hot-mix asphalt plants usually employ a primary collection
device to recover dust from the exhaust stream, which is returned
to the process, and to reduce the dust loading on. secondary air
cleaning devices. Almos't all asphalt plants employ either simple
cyclones or multicyclones as primary collection devices. These
devices collect from 50% to.90% (by weight) of the dust in the
gas stream.
Many design factors affect the collection.efficiency of cy-
clones. Generally, higher pressure drop, greater flow rate, and
smaller cyclone radius increase collection efficiency. An upper
limit on the flow rate is established by the development of
turbulent flow which re-entrains the collected material. Also,
poor design or construction practices can yield a high pressure
drop and a low collection efficiency. The improved collection
efficiency of smaller radius cyclones is utilized in the multi-
cyclone where a number of small cyclones are operated in a parallel
arrangement. The performance of cyclones collectors is directly
Q
"Controlling Air Pollution in Asphalt Paving", Fred Kloiber,
Pollution Engineering, September 1977, p. 48.
-------
related to the particle size distribution in the gas stream;
collection efficiency decreases with decreasing particle size.
Cyclones and multicyclones alone cannot achieve the degree
of control required of asphalt plants by NSPS.
2.5.2 Baghouses
Almost all baghouses used to control emissions from asphalt
plants are the reverse-pulse or reverse flush type. Usually
the bags are supported on a wire cage with the interior of the
bag being the clean side. (Figure 2-1). The fabric bags are
usually 14 to 16 oz. (weight per square yard) felted or felted-
woven Nomex* bags.
The term "air-to-cloth ratio" refers to the ratio of the
volumetric flow rate through the baghouse to the total filter area
of the bags (acfm/ft2). The terms "superficial face velocity"
and "filter velocity" are also used, since cancelling units in
the ratio .results in ft/min. For reverse-pulse and reverse
flush baghouses at asphalt plants, air-to-cloth ratios range from
4 to 7 acfm/ft. 10
In the reverse-pulse type baghouse, removal of the accumulated
dust cake is accomplished by directing a pulse of compressed air
into the interior of individual bags. The high pressure air causes
the bag to snap from a collapsed condition on the wire support
cage to an expanded (ballooned) position. The abrupt change in
the bag configuration causes the dust cake to fall from the bag
to a hopper at the bottom of the baghouse. In the reverse-flush
baghouse, cleaning is facilitated by isolating a group of bags
by means of dampers. Compressed air is introduced to the exhaust
chamber above the bags which causes the bags to expand rapidly,
thereby removing the dust cake. The frequency and duration of
the cleaning cycle can usually be adjusted by the plant operator.
Sometimes the cleaning cycle is automatically controlled by a
device which senses the pressure drop across the bags.
*
Trade name
Operation of Exhaust Systems in the Hot-Mix Plant, National
Apshalt Pavement Association,Information Series 52, p. 34.
-------
FIGUR? 7 2'-1
TYPICAL PULSE-JET CONFIGURATION
Soiiis
Source: Handbook of Fabric Filter Technology,GCA Corp., Dec. 1970
10
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An older type of baghouse using woven fabric filters and
air-to-cloth ratios in the range of 1 to 4 acfm/ft is sometimes
encountered. This type of baghous relies on the collected dust
cake to act as part of the filter. Periodic cleaning is ac-
complished by mechanically shaking the bags. Only a few older
asphalt plants employ this type of baghouse.
2.5.5 Wet-Collection Devices
Wet-collection devices, or scrubbers, employ two principal
mechanisms for the removal of particulate matter from gas streams:
l)Dust particles are wetted by contacting them with a liquid.
Wetting the particles increases their effective mass, which
facilitates collection by impingement on centrifugal devices.
2) Dust particles are contacted'.'. with a collection surface by im-
pingement or other.means and are then removed by a liquid flush.
In some cases, the collection surface is the scrubber water.
Many wet-collection devices employ both of these mechanisms for
particulate collection.
High Energy Venturi Scrubbers. High Energy venturi scrubbers
are the most effective wet-collection devices for controlling
particulate emissions at asphalt plants. In the venturi scrubber,
the dust laden gases are passed through a venturi which consists
of a convergent section, throat, and a divergent section (Figure 2-2),
Gas velocities in the throat range from 76 to 102 meters per second
(15,000 - 20,000 fpm) with pressure drops across the venturi ranging
from 254 to 762 mm (10-30 inches) of water column. Low
pressure water is injected either directly into the throat or in
the convergent section. Turbulence created by the high velocity
gas stream atomizes the liquid into a very fine mist. The dust
particles collide with the liquid droplets due to the high relative
velocities in the throat, thus increasing the mass of the par-
ticles. Further agglomeration occurs in the divergent section
creating relatively large particles which are removed in a
cyclonic or other inertial separator.
11Air Pollution Engineering Manual, U.S. EPA,AP-40, May,1973,p.104.
11
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Figure 2-2. Venturi Scrubber
Source: Air Pollution Engineering Manual, U.S. EPA AP-40, 1973
12
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Low Energy Scrubbers. Low-energy wet collectors are
devices with pressure drops of less then 15" we and include such
devices as spray systems, centrifugal scrubbers, orifice scrubbers,
and wet fans. Alone, none of these devices are capable of achiev-
ing the required degree of control. However, tests have shown
that the NSPS emission standard can be met with the use of two
or more low-energy scrubbers in series.
There is considerable variability in low-energy scrubber
design among the various manufacturers. There is even greater
variability in the combinations of these devices at aspahlt
plants. Improvised systems are frequently used in an attempt
to meet the required emission standard. Several low-energy
scrubber systems are shown schematically in Figure 2-3.
12
Background Information for New Source Performance Standards,
U.S. EPA (APTC-1352c) Vol. 3, p. 10)
13
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Scavenger \Svstem
Spray Nozzles
:Dryer x Exhaust
Wet Fan
Cyclone
Freeleaner
f
stack
H^
)
1 -~
i — .
i
x'
1 1
1
• Spray
Wet
Centrifugal
Collector
Exhaust Fan
Scavenger
v. oysuein
Dryer
Exhaust
\
Multiple
.Centrifugal
Scrubber
r
Stack
->-
Figure 2 - 3• Low-Energy Scrubber Systems
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Chapter III
EMISSION CONTROL REGULATIONS
State and Federal regulations have been established to limit
particulate emissions to the atmosphere at asphalt plants.
3.1 Federal Regulations- Standards of Performance for New or
Modified Asphalt Concrete Plants
The current standards regulating particulate emissions from
asphalt plants were published March 8, 1974 (39 FR 9308). These
standards apply to hew sources, plants whose construction or
modification* was undertaken after June 11, 1973. The standards
limit particulate emissions to:
(1) No more than 90 mg/dscm (0.04 gr/dscf)
(2) Less than 201 opacity2
"The concentration standard applies to emissions of parti-
culate matter from the control system, as evidenced by the test
methods required for determining compliance with this standard."•*
The regulations also require the operators of asphalt plants to
conduct a performance test and submit the results within 60 days
after achieving the maximum production rate at which the affected
facility will be operated, but not later than 180 days after ini-
tial start-up (40 CFR 60.8). The appropriate test methods for
determining compliance are described in Chapter VI.
lit should be noted that relocation, change of ownership, and
upgrading of emission controls are not, by themselves, modifications
(40 CFR 60.14 (e) ). These occurrences are particularly common at
asphalt plants.
2Qccasionally a plant operator will add small amounts of as-
bestos to asphalt mixes to increase the cohesion and abrasion re-
sistance of the product. Asbestos is usually supplied in sealed
plastic bags which are added directly to the mixer.
Any new or existing asphalt plant which uses asbestos in the
production of asphalt concrete is subject to the National Emission
Standards for Hazardous Air Pollutants (40 CFR 61.22 Cll). The
standard for asbestos manufacturing operations allows no visible
emissions of asbestos-containing particulate matter to the outside
air unless a specified fabric filtration device is employed (40 CFR
61.23) .
^Background Information for New Source Performance Standards,
U.S. EPA (APTD-1352C), Feb. 1974, p. ^"~
15
-------
The opacity standard, to ensure that emissions of parti-
culate matter are properly collected and vented to a control
system4, applies to "dryers, systems for screening, handling,
storing, and weighing hot aggregate; systems for loading, trans-
ferring, and storing mineral filler; systems for mixing asphalt
concrete; and the loading, transfer and storage systems associated
with emission control equipment" (40 CFR 60.90). The opacity
standard applies to all of the above named fugitive dust sources
and to stack emissions from all control systems.
3.2 State (SIP) Regulations for Asphalt Concrete Plants
All states have laws which affect the ;hot-mix asphalt
industry. Many states have dual standards; one for existing
plants and a more stringent standard for new plants. Table
3-1 is a tabulation of state, (SIP), particuiate and opacity
regulations; The values listed are illustrative only 'arid should
not-be used for enforcement purposes.
Most states limit particuiate emissions in terms of Ibs/hr
where the allowable emission rate is determined from'process
weight rate tables. 5"- Some states employ concentration standards
Cgr/dscf) or other means of limiting emissions. The basis for
the particuiate emission standard often affects the test
method(s) which are used to determine compliance with the
standard. For example, a mass emission rate standard' (Ibs/hr)
requires that the tester determine the stack volumetric flow
rate, however, a concentration standard does not. Most states
employ EPA Methods 1-5 for particuiate sampling, however test-
ing details vary from state to state. For example, most
states count only the particuiate collected in the front half
of the Method 5 train, however, some states also count parti-
cuiate collected in the impingers. Factors in the state
4Ibid. . . . ••'.-.:
Air Pollution Regulations Study, Information Series 49,
National Asphalt Paving Association, 1973.
16
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Table 3-1. Summary of State Regulations
State
Allowable Emission Rates % Opacity
Ibs/hr,process wt. depen- Provisions
dent except where noted
State
Allowable Emission Rates % Opacity
Ibs/hr,process wt. depen- Provisions
dent except where noted •
Alabama 9.76-46.79/12.05-68.96 20
Alaska 0.05/0.10 a 20
Arizona 12-69 40
Arkansas 9.73-46.72 20/40
California Each county has its own regulations
Conn. 0.3 lbs/1000 Ibs dry discharge gas . 20
Delaware 10-50 20
D. Colum. 10-40 0
Florida 9.73-46.72 20
Georgia 5.52-43/5.0-91 20
Hawaii 13.6-40 20/40
Idaho 12-69 20/40
Illinois 6-67/12-69 30
Indiana 12~6| 40
Iowa 0.15 40
Kansas 12-69 20/40
kentUcky 12-69 20/40
Louisiana 12-69 20
Maine 9.73-46.72 40
Maryland 0.03 0
Mass. 4.5-18.1/9.0-36.2 20
Michigan 0.3-0.6 lbs/1000 Ibs wet flue gas 20
Minnesota 0.1-0.042 a' 20
Miss. 12-264 40
Missouri 12-69 20/40
Montana 12-69 20/40
Nebraska 12-69 20
Nevada 12-69 20
N. Haopsh. 10-47 20
N. Jersey 0.02 a'c 20
New Mexico 10~59 20
New York 0.03-0.05a' /10.8-71.1 20
N. Car. 10-60 20/40
N. Dakota 12-69 20
Ohio 4-220 lb/hre or 12-69 20
Oklahoma 12-69 20
Oregon 10-69 20/40
Penn. 3.18-13.3 or 0.02 20
Rh.-Is. 12-69 20
S, Car&lina 22-65/30-94 20/40
S. Dakota 21-69 20
Term. 9.7-46.7 and 0.25S/12-51.2 20/40
Texas 14.5-60.4 20/30
Utah Maintain 85% collection effici; 20/40
Vermont 0.07 S/6.67-40 NA/40
Virginia 10-50 20
Washingt. 0.10 a 20
W. Vir. 10-50 20
Wisconsin 9.73-46.72/some areas differ 20/40
Wyoming 9.73-46.72/12-69 20/40
gr/dscf
dependent upon source gas volume(scfm)
dependent upon Ib/hr emission rate
uncontrolled mass rate basis
or control equipment of 99% efficiency, whichever is less
1
whichever is greater
Whenever available listed according to new source standard,existing source
-------
regulations which affect how a source test is to be con-
ducted must be ascertained in the developmental stages of
the test.
Opacity regulations vary from "no visible discharge'
to 40% opacity. Many state regulations allow opacities
greater than the standard for short time periods. Many
states also have regulations for fugitive dust and odor
emissions. These emissions are often dealt with on a
nuisance basis.
18
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Chapter IV
PROCESS PARAMETERS AFFECTING POTENTIAL EMISSIONS
The first section of this chapter explains how process
variables and operational parameters are related to the dust
loading on control equipment. Section 4.2 describes commonly
encountered values of important process parameters. Examples
of process modifications and operational practices which are
sometimes employed to achieve short term emission reductions
are provided in section 4.3.
4.1 Process Variables and Their Relation to Dust Loading.
Rotary Dryer. The dryer is the major source of potential
particulate emissions at asphalt plants. There are several
operational parameters which affect the dust discharge rate
from the rotary dryer. The two major factors affecting
particulate emissions are: (1) the quantity of fine material
in the dryer, and (2) the flow rate of gases through the dryer.
These two factors are directly related to process variables
such as: production rate, aggregate size distribution,
aggregate moisture content, firing rate and excess air.
The aggregate size distribution in the dryer feed has a
significant effect on the dust emissions. Dust carryover increases
as the particle size decreases. In addition to the mineral dust
in the dryer feed, very fine particles are created in the dryer
by breakup of coarser aggregate. Tests have shown that approx-
imately 55$ of the mineral dust (material less than 74 microns)
in the dryer feed may be lost in,the processing. The amount
of small particles in the dryer, is dependent on both
the percentage of fines in the dryer feed and the total production
rate.
Pollution Engineering Manual,U.S. Environmental Protection
Agency, AP-40, May, 1973" p. 328.
19
-------
The volume flow rate of gases through the dryer has a
major effect on the dust discharge rate. A study by Barber-
Greene reported that dust carryover was proportional to the
2 •
square of the gas velocity through the dryer. Therefore,
the"gas flow rate should be kept to the minimum necessary
for proper operation of the dryer to reduce particulate
entrainment. .
The firing rate of the dryer is directly related'to the
aggregate feed rate, the percent moisture in the cold aggregate
feed, and the required hot aggregate temperature. If any of
these factors increases, the amount of heat supplied to the
dryer must be increased. This is accomplished by increasing '
the firing rate.
To increase the firing rate, the quantity- of vfuel, supplied
to the burner is increased. At the same time, the amount of air
supplied to the burner, which, is brought in by a forced-draft
fan in the burner itself and by the induced draft of the
exhaust fan following the dryer, must be increased to maintain
proper combustion conditions. Thus, the flow rate-of gases
through the dryer is related to the rate and moisture content
of the aggregate feed.
Excess air is defined as the quantity of air in excess of
the theoretical amount necessary for complete combustion of the
fuel. Due to less than ideal combustion conditions a certain
amount of excess air must always be present in combustion
processes to ensure .complete combustion of the fuel. Normally..
10 to 25% excess air is sufficient for the operation .of gas or
oil-fired burners. In aggregate dryers with low exhaust
temperatures, additional excess air may be required to prevent
dryer gases from becoming saturated with water vapor. A state
of saturation or high relative humidity in the dryer gases will
retard the evaporation of water from the aggregate.
In direct fired rotary dryers, too much excess air lowers
the flame temperature, reduces the effective heat transfer to
"Dryer Principles", The Barber-Greene Co., Aurora, 111. (1969)
20
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'the aggregate, wastes the fuel required to heat the excess air,
and increases the gas flow rate through the dryer. This in turn
increases the dust emissions.
In order to maximize the efficiency of the dryer and to min-
imize the amount of dust lost, the firing rate of the burner and
the draft must be balanced carefully. For a given process rate
and aggregate moisture content, the firing rate should be
adjusted to provide the minimum amount of heat necessary to
dry and heat the aggregate properly. The draft should be
regulated to provide the correct amount of air for complete
combustion and, when necessary, sufficient excess air to ensure
that a state of high relative humidity does not occur in the
dryer gases.
Most hot-mix plants have controls which allow modulation
of the burner to provide the required firing rate. Part of the
air for combustion is supplied by the forced draft blower, which
forces air- through the burner to ensure thorough mixing of the
fuel and air. The quantity of air supplied by the forced draft
blower is regulated by the burner controls. The remainder of
the air flow through the dryer (approximately 70%) is provided
by the exhaust fan. Exhaust fans are usually located either
immediately before or after the secondary control device. The
flow of gases through the dryer is regulated by a damper in the
ducting between the dryer and exhaust fan. A procedure commonly
used to obtain the proper air flow is to close the damper until
puffback occurs (visible emissions of dust and smoke from the
air inlet end of the dryer). The damper is then slightly re-
opened.
On almost all hot-mix plants, the hot aggregate temperature
is monitored to ensure that the aggregate is at the desired
mixture temperature. Many plants also monitor the dryer exhaust
gas temperature. An exhaust gas temperature from 90 to 120°C
(200-250°F) desired. 3 Some plants have little ability to
The Operation of Exhaust Systems in the Hot-Mix Plant,
National Asphalt Paving Association, Information Series
52., 1975, p. 14
21
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regulate the firing rate and do not have a damper or other
means of regulating air flow. These plants are usually run
wide open (maximum production rate) with little attention
given to maintaining the correct firing conditions in the
dryer.
The type of fuel used can have a noticeable effect on
emissions from the dryer. Usually gaseous fuels or fuel oil
are used to heat the dryer. The use of heavy fuel oil may
result in unburned fuel droplets or soot particles in the
dryer exhaust due to poorly maintained burners or improper
combustion conditions. Tests have shown that emissions were
increased more than 5 Ibs. per hour when No. 6 fuel oil was
used in place of natural gas at a plant controlled by multiple
centrifugal scrubbers. Frequently, the added increment of
particulate emissions from a misadjusted or defective oil
burner will cause the standard to be exceeded. The combustion
of fuel oil containing sulfur will produce sulfur oxides
(SO-, SO,). The presence of these compounds, especially when
£,. • - 3 • - _ , • • . " (
the gas stream is wet, increases the corrosion problems in
the system. When high sulfur fuels are used at plants
equipped with wet-collection systems, water treatment may be
necessary to prevent the scrubber water from becoming acid.
The rotational speed of the dryer and the number of
flights may also affect the amount of dust discharge from the
dryer. An addition of flights or an increase in rotational
speed increases the amount of time the particles are in the
veil suspension. Particles in the veil suspension are the most
susceptible to entrainment in the gas stream.
4 Air Pollution Engineering Manual, U.S. EPA, AP-40, May 1973,
p. 330.
22
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'Secondary Sources. Particulate emissions from secondary
sources, (hot elevator, screens, hot bins, weight hopper,
and mixer) are controlled by enclosing the aggregate
handling equipment with a scavenger ducting system. The
particulate loading in the scavenger system varies with
the condition of the aggregate handling equipment and the
quantity of fine material in the mix. The design and physical
condition of the scavenger system (particularly the effective-
ness of the seals) affects both the required volumetric flow
rate for the system and the amount of dust which is entrained.
For a typical plant the ventilation requirements of the
scavenger system are on the order of 5100 to 5950 m /hr
C3000-3500 cfm).5
4.2 Normal Range of Process Parameters - Plant Capacity
The following values of process parameters indicate the
normal or typical ranges encountered at most asphalt plants.
However, considerable deviations from the given ranges are
observed at some plants.
Aggregate Size Distribution The compositions of various
asphalt mixes are summarized in Table 4-1. The values
given in the table are percent by weight of.the aggregate
passing the given screen.
5 Air Pollution Engineering Manual, U.S. EPA, AP-40,
May 1973, P. 328.
23
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Table 4-1 Mix Compositions
Ml.1
Type
1 a
II a
II b
II c
II d
II e
III a
III b
III c
III d
III e
IV a
IV b
IV c
IV d
V a
V b
Via
VI b
VII a
~ VIII a
2K
in.
100
I'/i in.
35-70
100
100
100
1 in.
100
70-100
100
75-100
160
80-100
% in.
0-15
100
70-100
50-80
100
100
75-100
60-85
100
66- )00
70-90
100
160
'/i in.
100
70-100
100
75-100
75-100
100
80-100
100
85-1 OO
100
-
Hin.
10O
70-100
45-75
35-60
25-60
75-100
60-85
60-85
45-70
40-65
80-100
70-90
60-80
55r75
85-100
85-100
85-100
.100
#4
40-85
20-40
20-40
15-35
10-30
35-55
35-55
30-50
30-50
30-50
55-75
50-70
48-65
45-62
65-80
65-80
85-100
100
#8
0-5
5-20
5-20
5-20
5-20
5-20
20-35
20-35
20-35
20-35
20-35
35-50
35-50
35-50
35-50
50-65
50-65
65-78
65-80
80-95
95-100
#16
37-52
37-52
50-70
47-68
70-89
85-98
#30
10-22
10-22
5-20
5-20
5-20
18-29
18-29
19-30
19-30
25-40
25-40
35-60
36-55
55-80
70-95
#50
6-16
6-16
3-12
3-12
3-12
13-23
13-23
13-23
13-23
18-30
18-30
25-48
26-46
30-60
40-75
#100
4-12
4-12
2-8
2-8
2-8
8-16
8-16
7-15
7-15
1 0-20 *
10-20
1 5-30
16-25
10-35
20-40
#900
0-3
'0-4
0-4
0-4
0-4
0-4
2-8
2-8
0-4
0-4
0-4
4-10
4-10
0-8
0-8
•3-10
3-10
6-12
3-8
4-14
8-16
Percent
A»ph*n
3.0-4.5
4.0-5.0
4.0-5.0
3.0-6.0
3.0-6.0
.3.0-6.0
3.0-6.0
3.0-6.0
3.0-6.0
3.0-6.0
3.0-6.0
3.5-7.0
3.5-7.0
3.5-7.0
3.5:7.0
4.0-7.5
4.0-7.5
4.5-8.5 .
4.J-8.S
7.0-1 1.0
7.5-12.0
Coarse Aggregate
Fine Aggregate
Mineral
Dust
I Macadam
i II Open Type
i CD Coarse Graded
i IV Dense Graded
V Fine Graded
i VI Stone Sheet
. VD Sand Sheet (Sand Asphalt)
VIII Fine Sheet (Sheet Asphalt)
Aggregate Moisture Content - usually 3-71. Aggregate moisture
content varies depending on source of material and storage
conditions. Moisture content can be expected to increase
following rainy weather.
Hot Aggregate Temperature - normally 93 to 150°C (200-300°F).
Required hot aggregate temperature varies with the type of
mix produced and the distance to the paving site.
Dryes Exhaust Temperature. The desired dryer exhaust tempera-
ture is 93 to 190°C (200-375°F). The actual exhaust temperature
is often higher.' In"no case can'the dryer.exhaust temperature
be less than the hot aggregate temperature.
The Asphalt Handbook, Asphalt Institute, Manual Series No. 4,
March 1966, p. 68.
24
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Fuel - Natural gas, No. 2 - No. 6 fuel oil. Fuel consumption
typically varies from 1.7 to 4.9 gal per ton of aggregate.
Heat Distribution of Dryer Exit
Hot Aggregate 40 - 50%
Water Vapor 30 - 45%
Combustion Gases 2.5-5%
Excess Air 7 - 15%
Heat losses from the dryer (casing losses) typically 10-25%
of the gross heating value of the fuel burned.
Excess Air. Minimum necessary for proper combustion, 25%
typical range encountered, 25% - 60%. Excess air values
greater than 300% are sometimes encountered at plants with
little ability to regulate draft and firing rate.
Plant Capacity. The maximum production rate or plant capacity
is usually limited by the quantity of aggregate that the rotary
dryer can process. Only in rare cases is plant capacity limited
by screening, mixing, or other aggregate handling operations.
Dryer capacity is the quantity of aggregate which can be
dried and heated in a specified time interval (tons/hour).
Manufacturers normally specify the rate (capacity) of dryers at
a specified aggregate moisture content, usually 5%. In
practice, dryer capacity is limited by the capacity of the
exhaust fan or by the amount of heat which can be supplied
by the burner. Many plants have a limited exhaust system
capacity due to the addition of air cleaning equipment without
a corresponding increase in fan capacity.
The Operation of Exhaust Systems at Hot-Mix Asphalt Plants,
National Asphalt Pavement Association Information, Series 52,
1975, p. 2.
25
-------
For a given heat input rate, the quantity of aggregate
which can be processed is largely dependent on the moisture
content of the feed. For a typical plant, an increase of 1%
in the moisture content decreases as the process weight rate
by approximately 10 to 15% based on a fixed heat input rate.
If the dryer capacity is limited by the exhaust system capacity,
the firing rate cannot be increased without unbalancing the
combustion process. Under these conditions, an increase in
moisture content requires reduction, of the process weight
rate to achieve the proper heat input per ton of aggregate
processed. A further reduction in process weight rate is
necessary in order that the exhaust fan can handle the additional
volume of water vapor.
4.5 Process Modifications
Almost any of the process variables and operational
parameters which .have been discussed in the preceding .•sections
can be adjusted or modified to' achieve short term reductions
in the dust loading on air pollution control equipment. The
most common operational modification is "fine tuning" of the
process using existing -.plant controls to (1) minimize the
firing rate, (2); increase combustion efficiency or (3) reduce
the quantity of/excess air used in the rotary dryer. Testing
under these conditions may or may not'Constitute .representative
conditions for the performance test. In most cases, it is
difficult to prevent "fine tuning" of the process up to the
point where the operational modifications affect the production
capacity of the plant. If "fine tuning" procedures are
employed to reduce potential emissions during the performance
test, then the same operational procedures and conditions
must be maintained during future day-to-day operation of the plant,
Heating and Drying of Aggregate, Dr. P. F. Dicerson,
National Asphalt Pavement Association, May, 1971.
26
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Examples of temporary process modifications which can
be employed to reduce the gas flow rate through the dryer
and thus the dust loading on control equipment are:
(1) reduction of fan speed, (2) increasing the flow rate
through the scavenger system thereby reducing the flow rate
through the dryer or (3) introducing dilution air to the
dryer exhaust system to reduce the draft on the dryer. All
of these modifications also reduce the production capacity
of the dryer for those plants were exhaust system capacity is
the limiting factor.
A minor process parameter which is often overlooked is
the hot aggregate temperature. The desired hot aggregate
temperature varies with the type of mix being produced.
Lowering the hot aggregate temperature allows the firing
rate and the gas flow rate through the dryer per ton of product
to be reduced. Therefore, if a relatively low temperature
mixture is produced during the performance test, then the
production rate should be increased to accurately reflect
plant capacity.
For tests requiring measurement of the production rate,
it is to the source's advantage to start the test with the hot
bins empty. Thus, if the quantity of material in the hot bins
and/or storage facilities can not be accurately determined
before and after the test, then the apparent production rate
nay be greater than the actual production rate.
Many states have emission standards based on the ratio
of the emission rate (Ibs/hr), to the process weight rate
(tons/hr - cold aggregate feed rate plus the quantity of
asphalt cement used). For a fixed emission rate (Ibs/hr),
the particulate emissions in terms of the standard decrease
as the process weight rate increases. The process weight
27
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can be significantly increased with little affect on emissions
by adding a substantial amount of large aggregate to the cold
aggregate feed. The coarse aggregate may be rejected in the
screening operation or may result in overflow of the coarse
aggregate hot bin. In either case, a portion of the large
size aggregate is included in the process weight but is not
included in the asphalt product and contributes little to the-
emissions from the dryer.
It should be emphasized that by carefully and completely
monitoring the process during the performance test almost
all significant operational modifications can be eliminated
or at least, documented.
28
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CHAPTER V
CONTROL SYSTEM PARAMETERS AFFECTING EMISSIONS
The first section of this chapter explains how control
system variables affect emissions and describes the typical
parameters ranges for various control devices. The second
section provides examples of control system modifications
which can be employed to achieve short term emission
reductions.
5.1 Control System Parameters
Pressure Drop. The pressure drop across a control
device is an important operational parometer for all control
equipment found at asphalt plants. The pressure drop is a
measure of the power expended in forcing the system gases
through a collection device. The pressure drop (the difference
between inlet and outlet static pressures) is a function of
both the flow resistance of the device and the volumetric
flow rate through the device. For a given flow rate, the
pressure drop increases if the resistance to flow increases.
For a given flow resistance, the pressure drop decreases as
the flow rate decreases. The three variables, flow resistance,
flow rate, and pressure drop are inseparably related, at least
one of the three variables must be specified to establish
a known relation between the other two. It should be noted
that the same principles apply to the water supply lines for
wet-collectors.
Baghouses. The parameters which affect or are indicative of
the operation of baghouses are the pressure drop, air-to-
cloth ratio, and cleaning cycle frequency. The particulate
collection efficiency of the reverse-pulse and reverse-flush
29
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baghouses is usually dependent only on the condition of the
filter bags. Tests have shown that the particle size distri-
bution has little affect on the emission rate.
Pressure drop across baghouses normally ranges from 10
to 15 CM (4-6 in.)of-water column. The pressure drop is
dependent on the air-to-cloth ratio and on the thoroughness
and frequency of the cleaning cycle. The air-to-cloth ratio
is typically 1.2 to 2.1 m/min (4-7 ft/min.).
The frequency of the cleaning cycle is usually controlled
by either a timer or by a device which senses the pressure
drop across the baghouse. The thoroughness of the cleaning
cycle for reverse-pulse baghouses is in part dependent on the
pressure of the compressed air used to clean .the bags.. In-
sufficient cleaning results in large pressure drops across
the baghouse and may reduce the capacity of the exhaust system.
Excessive cleaning often results in rapid wear of the filter
bags, particularly where the bag contacts the wire support
cage, torn or severely worn bags or leaks in the baghouse
greatly reduce the collection efficiency of the baghouse
and are usually accompanied by insufficient pressure drop
across the baghouse.
Temperature and moisture limitations are extremely
important in the—ope-r-ation of baghouses. Protective devices
and operating procedures are designed to.ensure that the gas
temperature in the baghouse does not exceed the filte.r
temperature limit, normally 232°C (450° F) for Nomex* bags.
Care must also be taken that the gas temperature does not
fall below the dew point. If this occurs, water will condense
on the bags resulting in blinding of the filters. The temp-
erature and moisture limitations of the baghouse restrict the
Background Information for New Source Performance Standards,
U.S. EPA (APTC-1352a) Vol. 1, p. 12.
Tiade name.
30
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range of dryer operating variables to those which produce
exhaust gases within the acceptable limits.
Wet-Collection Devices. The principal factors governing
collection efficiency include the condition of the inlet gases
(dust loading, particle size distribution), the kinetic energy
energy of the gas stream (velocity head), and the kinetic
of the collection liquid. For a given inlet dust loading and
particle size distribution, it is commonly felt that collection
efficiency is directly related to the total power expended
in forcing the gases through the collector and in generating
2
water spray.
Most asphalt plants which are equipped with wet-collection
devices recirculate the scrubber water. A settling pond is
almost always employed to remove the -"fcotafeegEspr particulate
material from the scrubber water. Particulate emissions
may be increased if the water used in the scrubber system
contains a large amount of solid material (silt). In addition,
the pressence of large amounts of solids in the inlet scrubber
lines leads to rapid deterioration of spray nozzles, pressure
gages, water flow meters and other components of the scrubber
system.
Venturi Scrubbers. The venturi design, pressure drop, water
injection rate, and particle size affect the collection
efficiency in venturi scrubbers. Some venturi designs include
adjustable throat openings. Decreasing the throat area
increases the gas velocity in the throat which increases both
the extent of liquid atomization and the relative velocity
between the dust particles and liquid droplets. These
conditions increase the frequency of collisions between
particles and droplets which increases collection efficiency.
AIR POLLUTION ENGINEERING MANUAL U.S. EPA (AP-40)
May, 1973, P.100.
31
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Constricting the throat area increases the pressure drop
across the collector. Also, an increase in the volume flow
rate will increase the pressure drop. The collection efficiency
for a given dust concentration and particle size distribution
is directly related to the pressure drop across the device.
Collection efficiency can usually be increased if additional
fan horsepower is available.
It should be noted that at a fixed throat opening,
reducing the volumetric flow rate of exhaust gages through
the venturi will reduce the pressure drop and the collection
efficiency of the device. Therefore, operating an asphalt
plant equipped with a venturi scrubber at reduced load may
increase the particulate emissions per ton of product.
Generally, an increase in the water injection rate will
create more liquid droplets which increases collection efficiency.
An increase in water injection rate is usually accompanied by a
slightly increased pressure drop across the collector. Typical
. -. 7 i
water injection rates range from .80 to 1.34 1/m (6-10 gal/
3 3
1000 ft. of gas). Water usage rates in excess of 1.35 1/m
(10 gal/1000 ft. ) produce only slight increases in collection
efficiency.
As in most collection devices, the collection efficiency of
the venturi scrubber is directly related to particle size; de-
creasing particle size decreases efficiency; For a typical
venturi scrubber with a 20" WC pressure drop and 8 gal/ 1000 ft
water injection rate, 95% to 98% collection for l/i to 5/x particles
is expected. Efficiency falls off sharlply below ]/u (50%
collection for . 5/t particles) .
Operation of Exhaust Systems in the Hot Mix Plant, National
Asphalt Pavement Association- Information Series 52, p.26.
32
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Low-Energy Scrubbers. There is great diversity and variability
among the low-energy scrubber systems found at hot-mix asphalt
plants. The most commonly encountered components of these systems
include: wet-fans, spray systems, wet-centrifugal collectors
and orifice scrubbers.
Often, spray systems are used before existing exhaust fans
to provide wet-fan collectors. Water sprays are also used in
centrifugal devices to provide wet washers. The ability of the
spray systems to wet the dust particles is related to water usage
rate, water pressure, and the degree of atomization provided
by the spray nozzles.
>
The same operating principals apply to orifice scrubbers with
adjustable throats. Decreasing the size of the orifice increases
the pressure drop across the device, increases the effective fan
horsepower required to operate the device, and increases the
collection efficiency of the device. The efficiency of wet-
impingement and wet-centrifugal collection devices is generally
proportional to pressure drop, gas velocity and water usage rate.
Particle size distribution in the gas stream has a m-ajor effect
on the collection efficiency of low-energy scrubbers. These
devices generally have poor collection efficiencies for particles
smaller than Sjj.
5.2 Control System Modifications. The following paragraphs
describe control system modifications which can be employed to
achieve short term emission reductions.
Operation of Exhaust Systems in the Hot Mix Plant, National
Asphalt Pavement Association, Information Series 52, p. 24.
33
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Baghouses. The frequency of the cleaning cycle can be adjusted
to decrease emissions from baghouses during performance tests.
Either the time interval between cleaning cycles or the pressure
drop across the baghouse required to activate the cleaning
cycle can be increased. This allows the accumulated dust cake
on the bags to act as part of the filter thereby increasing
particulate collection efficiency.
At some plants the clean air plenum of the baghouse is
inspected prior to the performance test. Accumulated dust in
"the clean air plenum is indicative of torn or severly worn bags
or leaks in the interior of the baghouse. Leaks are then
patched and torn bags are either replaced or in some cases,
wooden plugs are used to effectively seal off individual bags.
These procedures obviously increase collection efficiency.
It should- be noted that plugging individual bags increases
the air-to-cloth ratio for the remaining bags which generally
reduces the useful life of the filters.
West-Collection Devices. There are several methods which can
be used to temporarily increase..the collection.efficiency of
scrubber systems. .Examples of these methods are provided in
the following paragraphs.
Particulate emissions are increased if the water used in
the scrubber system contains a large amount of solid particles.
Two different methods are used to reduce the solids content
of the scrubber water. First, the settling pond or lagoon
can be cleaned out to remove oil and accumulated silt prior
to the performance test. This procedure increases the effectiveness
of the settling pond and is considered part of the periodic
maintenance required for wet-collection systems. A second
procedure which is sometimes employed is to use tap water in
the scrubber system during the performance test. The use of
tap water should not be allowed unless the scrubber system will
use only tap water during future operation. If a relatively
small settling pond is used, the use of tap water can be
detected by noting the water level in the pond.
34
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An increase in the water pressure OT water usage rate
usually increases the collection efficiency of scrubber systems.
Auxiliary or stand-by pumps are sometimes used to increase the
water pressure and/or water flow rate to the scrubber. An
increase in pump speed at a constant delivery pressure will
also increase the water flow rate.
Due to the pressence of solid material in the scrubber
water, rapid deteroration (erosion and/or plugging) of spray
nozzles is to be expected at asphalt plants. Spray nozzles
are sometimes replaced prior to performance tests to increase
the effectiveness of water spray systems. This procedure is
difficult to prevent since replacement of spray nozzles is
considered normal maintenance. However, spray systems should
be inspected during performance tests to establish "normal
operating conditions" as a baseline for comparison during
future follow-up inspections.
The collection efficiency of venturi scrubbers with
adjustable throat openings can be increased by decreasing the
size of the opening. It should be noted that decreasing the
size of the throat increases the pressure drop across the
device and increases the fan capacity required to operate the
device, at a constant flow rate. If additional fan capacity
is not available, reduction in the size of the throat opening
will reduce the production capacity of the plant. The same
principals apply to orifice scrubbers with adjustable orifice
openings.
From the previous discussion it may appear that it is
relatively easy to temporarily increase the collection efficiency
of control devices at asphalt plants. However, it should be
emphasized that almost all control system modifications can
be eliminated or documented by carefully monitoring the control
system parameters during the performance test.
35
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Cihapter YI
REPRESENTATIVE CONDITIONS - TEST PROTOCOL - PRETEST MEETING
Detailed procedures for determining representative
conditions, developing test protocol, and conducting pretest
meetings are provided in Volume I, "Development, Observation,
and Evaluation of Performance Tests".
6.1 Determination of Representative Conditions
One of the most important tasks for the enforcement agency
in developing performance tests is the determination of repre-
tative conditions. Paragraph 60.8 (c) of NSPS states:
"Performance tests shall be conducted under such
conditions as the Administrator shall specify to the
plant operator based on representative performance of
the affected facility. The owner or operator shall
make available to the Administrator such records as
may be necessary to determine the conditions of the
.performance tests. Operations during periods of start- .
up, shutdown, and malfunction shall not constitute
: representative conditions of performance tests unless
otherwise specified in the applicable standard.** '
Many states have similar requirements for compliance tests. The
determination of what "conditions based on represantative per-
formance of the facility" means for "asphalt plants is at best
very difficult. The operating conditions of a particular plant
can be expected to vary due to fluctuations in the demand for
the product, changes in the type or grade of asphalt concrete
produced, changes in the type, source or moisture content of
the raw aggregate, or changes in the operating procedures or
control system parameters at the plant. Performance tests
conducted to determine compliance with NSPS are usually con-
ducted at the "normal" operating conditions which represent the
Development, Observation and Evaluation of Performance Tests,
currently being prepared by The Division of Stationary Source
Enforcement, U.S., EPA
36
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greatest particulate emission potential. In the simplest
of terms, the maximum production rate anticipated using the mixture
generally produced which contains the greatest percentage of
very fine aggregate. (See chapters IV and V for additional
parameters which must be considered.) For asphalt plants
subject to state regulations, the permit issued by the state
enforcement agency may stipulate testing conditions. Most
state regulations are based on process weight: the emission
standard becomes more stringent as the process weight rate
is increased. This also requires testing at the maximum
production rate.
The agency personnel responsible for determining rep-
resentative conditions must have a thorough understanding of
how all process and control system parameters affect the
operation and emissions of the particular asphalt plant being
considered. This requires correspondence with the source and
may require a trip to the source if unusual conditions are
encountered. When possible, representative conditions should
be based on past production records. Production records
for new; sources.will of course be very limited.
The agency has two options to consider in determining
representative conditions: (1) Specify to the source the
conditions which will be maintained during the test. (2) Request
the source to suggest the conditions which will be maintained
during the test. The first option requires a great deal of
information to be obtained and documented to fairly assess
what constitutes representative conditions for a particular
plant. The second option requires that the agency reviews the
sources suggested conditions to determine if the conditions
are both reasonable and enforceable. If the second option is
employed the plant should be informed that future operation of
the asphalt plant at conditions which represent greater
potential emissions will require the plant to be retested.
37
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Regardless of which option is employed, when the represent-
ative conditions are finally established the agency should
specify the conditions of the test in a formal letter to
the source.
6.2 Test Protocol
The test protocol submitted by the source is a complete
description of what will be done to satisfy the performance
testing requirements. The agency should be careful to request
only the information which is necessary for the evaluation
of the proposed performance testing program at the particular
installation being considered. A summary of what should be
included in. the test" protocol is provided below.
Test,, Protocol ^ Asp.halt Concrete Plants
' . 1 . Proces-s • Opera't ing Goadi'feiionsc During ' Te s t - the test
-\ • j-pfotbcQl ^should; .coiEtaTin> exp.e'ct^d values and/or ranges of
: . < values^ /fqipthe^fo^lo^^^ Product iun
•'"' rate-; .a'gg.^e."gate?--nfei-&tu^^.tt^t-e'n-t^-' mixture compositio'n and
' ' * „"' ~ '"' ' . ''•'-?>" '• •'* - •'"•' ' ' '- - • - - .. -
' '; ...tempeTa^ure^ typeC^O'f^-fu?i^'ii!s;e'dJi. fuel con-sumption, and
.'•*•'.' • ' .' »•'" »>-"* ?••"•'•««. ~, .jjV,-"'/^'" • .. •
" "drye-r ex^ausitifVfeeJnp'e'fatiEcSe^J:. Thfe "source 'may also wish to
" '. % ' * ' ' * - ' j **• '/>; '. f ' *- v
propose alternate- operating conditions in the event : that
the maximum production rate^ or. other-, conditions specified
as "representative", can- not be obtained p.n the day: of the-
- test.
2. Control System Conditions During Test - The test protocol,
should contain estimated values of- control system parame-
ters for the appropriate control device:
A. Baghouses - type of bags, frequency of cleaning
cycle, cleaning air supply pressurej fan speed,
Fan Ap .
B. Scrubbers - Pressure drops (s) , water flow fate,
water pressure, source of scrubber water, and
venturi or orifice throat size (if adjustable) .
3. Procedures for Monitoring Operating Conditions - The
33
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protocol should contain a list of the process and control
system parameters which will be monitored during the
performance test. A description of the equipment and pro-
cedures which will be used to perform the monitoring
should be included.
4. Sampling and Analytical Procedures - The test protocol
should describe the test procedures which will be used to
determine the emission rate. Reasons for any deviations
from the specified methods and a detailed description of
any alternate.sampling and/or analytical methods should
be provided. Detailed drawings of the sampling site
should be included.
5. Performance Test Report - A description or list of what
will be included in the test report (See Chapter X, Source
Test Report Format) should be included in the test
protocol.
6. Tentative Schedule - The anticipated testing and reporting
schedule should be outlined in the test protocol.
The agency must review and determine the acceptability
of the test protocol submitted by the source. The process
and control system conditions contained in the test protocol
should agree with the representative conditions specified by
the agency. Careful consideration should be given to pro-
posed alternate operating conditions in the event "represent-
ative conditions" can not be maintained at the time of the
test. Similarly, alternate sampling procedures should be
examined to ensure that test results will be equal to or
higher than the actual emissions. Admendments to the sub-
mitted protocol may be necessary to obtain an acceptable test
protocol.
6.5 Pretest Meeting
The need for a pretest meeting is a function of the agen-
ies familiarity with the source and the number of questions
left unanswered by the test protocol review. A pretest
39
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meeting between the agency, source and test team is the last
opportunity to resolve problems before the performance test.
In many cases, a pretest meeting with only the agency and
source or with only the agency and test team may be sufficient,
If all problems are resolved with the review of the protocol,
then the pretest meeting need not be conducted.
40
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Chapter VII
EMISSION TEST METHODS AND ACCEPTABLE ALTERNATIVES
Acceptable sampling methods and procedures must be employed
to accurately determine the particulate emission rate during
performance tests. Alternative sampling methods must sometimes
be used when standard sampling procedures are not directly appli-
cable. In order to effectively review the test protocol sub-
mitted by the source, agency personnel must be familiar with
the test methods which may be encountered. The observer in the
field must also have a working knowledge of sampling procedures
to be able to ensure that proper methodology is employed.
Procedures for actually observing tests are detailed in Volume
II of "Development, Observation and Evaluation of Performance
Tests". An "Observers Sampling Checklist" is available in
Appendix C of this manual. This chapter describes the EPA
reference methods which are used to determine the particulate
emission rate at asphalt concrete plants. Commonly encountered
sampling problems and acceptable alternatives are also
discussed.
"Development, Observation and Evaluation of Performance Tests'
Currently being prepared by the Division of Stationary Source
Enforcement, U.S. EPA.
41
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7.1 Emission Testing Methods
The reference methods as published in the Federal Register,
Volume 42, No. 160, August 18, 1977, should be used to determine
compliance with Federal New Source Performance Standards. The
applicable reference methods for testing at asphalt concrete
plants are:
Appendix A - Reference Methods.
Method 1 - Sample and Velocity Traverses for Stationary
sources.
Method 2 - Determination of Stack Gas Velocity and
Volumetric Flow Rate.
Method 3 - Gas Analysis for Carbon Dioxide, Oxygen, Excess
Air, and Dry Molecular Weight.
Method 5 - Determination of Particulate Emissions From
Stationary Sources.
Copies of the above sampling methods are included in Appendix B
of this manual.
7.1.1 Method 1 - Sample and Velocity Traverses for Stationary
Sources
Method 1 provides criteria for selection of the sampling
location, determining the required number of sampling points, and
determining the locations of the sampling points. This method
can not be used where cyclonic flow occurs. At asphalt plants,
cyclonic flow often occurs after inertia! demisters following
wet scrubbers and in stacks with tangential inlets. Paragraph
2.4 of Method 1 provides explicit instructions for determining
when unacceptable flow conditions exist. In short, the angle
(between the pitot orientation and the plane perpendicular to
to the stack axis) required to produce a null reading is
measured for each sampling point. If the average of the absolute
values of the angles is greater than 10°, unacceptable flow
2
On August 18, 1977 the EPA promulgated revisions to reference
methods 1 through 8. The revised methods contain significant
changes from the methods which were previously in effect.
42
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conditions exist. Procedures for sampling cyclonic flow are
described in section 7.2.3 and in Appendix D.
The August 18, 1977 revisions of the reference methods
may require moving sampling port locations at some asphalt
plants when retested. The revised Method 1 requires that for
particulate traverses of round stacks, one of the traverse
diameters must be in the plane of the greatest expected
concentration variation. The length-to-width ratio requirement
of 2:1 for cross-sectional equal areas in rectangular ducts
has been replaced by a "Balanced matrix" scheme, which is
provided in table form.
7.1.2 Method 2 - Determination of Stack Gas Velocity and
Volumetric Flow Rate
Method 2 is not applicable to cyclonic flow systems.
Procedures for sampling cyclonic flow systems are discussed in
section 7.2.3 and in Appendix D.
Method 2 is performed concurrently with Method 5 to obtain
velocity measurements which are required to determine isokinetic
sampling rates. It should be noted that to determine compliance
with NSPS for asphalt concrete plants (concentration standard)
it is not necessary to calculate the stack volumetric flow rate.
However, it is suggested that the volumetric flow rate be
determined since it is an important operational parameter for
asphalt plants. The cross-sectional area of the stack is the
only additional data required to calculate the stack gas
volume flow rate.
7.1.3 Method 5 - Gas Analysis for Carbon Dioxide, Oxygen, Excess
Air, and Dry Molecular Weight
At asphalt plants method 3 is employed only to determine the
dry molecular weight of the effluent stream. Any of the sampling
techniques described in Method 3, grab sampling, single point
integrated sampling, or multi-point sampling, can be used for
43
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this determination. Either an orsat or Fyrite* analyzer may be
used for the analysis.
Paragraph 1.2 provides examples of alternative procedures
which may be used, including (1) a method using %C09 or %09
£* . £ .
and stoichiometric calculations to determine molecular weight,
and (2) assigning a value of 30.0 for dry molecular weight in
lieu of actual measurements for processes burning gas or oil.
These methods may be used but are subject to approval by the
Administrator.
7.1.4 Method 5 - Determination of Particulate Emissions from
Stationary Sources
Although it is not explicitly stated in the method,
Method 5 is not applicable to cyclonic flow systems since the
method relies directly on Method 1 and Method 2.
Subpart I - Standards of Performance for Asphalt Concrete
Plants, (60.93) provides additional requirement for Method 5:
"The sampling time for each run shall be at least 60 minutes
and the sampling rate shall be at least 0.9 dscm/hr (.'053 dscf/
rnin-) except that shorter sampling times, when necessitated by
process variables or other factors' may be approved by the
Administrator". The intent of this section, in addition to
specifying the duration of the test,is to ensure that the
minimum sample volume be 0.9 dscm (31.8 dscf) rather than
imposing a sampling rate restriction. As stated, the sampling
rate limitation implies that the test would be unacceptable
if the sampling rate falls below 0.9 dscm/hr (0.53 dscf/min)
at any time-. The' sample volume restiction is necessary to
ensure enough particulate is collected to have a significant
weight. :
Other problems which are commonly encountered in the
application of Method 5 at asphalt plants are discussed in the
following section.
* Tradename
44
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7.2 Commonly Encountered Sampling Problems and Acceptable
Alternatives
There are several areas which often present sampling
problems when performance tests are conducted at asphalt plants.
Insufficient attention to these areas can easily result in
invalid sampling results. A large expenditure of time and effort
may result in little information being obtained. The most
commonly occuring problems relate to:
(1) intermittent process operation
(2) determination of the moisture content in the
effluent stream
C3) cyclonic flow
7.2.1 Intermittent Process Operation
Start ups and shut downs are common occurences at asphalt
plants. The hot-mix asphalt process is basically a series or
chain operation. A failure of any part of the operation almost
always requires the plant to shut down. Most plants do not
have any provisions for storing the completed asphalt mixture.
The flow of trucks used to haul the asphalt product is often
sporadic and the lack of available trucks often causes the plant
to shut down for a brief period. Failure of paving machines or
poor weather at the paving site may cause the plant shut down for
extended periods.
Both the test team and the observer should continually
watch the process and be prepared to cease sampling during plant
shut downs. Particular attention should be paid to the cold
aggregate feeder system and the number of available trucks. If
production is halted or if the aggregate feed for the dryer is
interrupted, sampling should be discontinued immediately. The
sampling train should be removed from the stack, and the time the
shut down occurred and the dry gas meter reading should be noted.
If the shut down is expected to last more than a few minutes,
the sampling train should be sealed to prevent loss or contam-
45
-------
ination of the sample. When production is resumed, sufficient
time should be allowed for the process to stabilize before
sampling is commenced. For plants equipped with baghouses,
the fan is usually turned on before the burner is fired and the
baghouse is allowed to warm up before the aggregate feed to the
dryer is resumed until the first batch of asphalt is completed
and the stack temperature has returned to within 5.5°C (10°F)
of the pre-shut down value.
If sampling is inadvertantly continued for some time after
the process is shut down, the sampling results will be biased
low. The observer should provide the testing team with the
option of repeating the sample run or applying an, adjustment
to the results. Subtracting the portion of the sample volume
which was collected while the process was not. operating, from
the total sample volume will provide results equal to-or greater
than the actual emissions from the plant. This is simply -an
application of the "bias concept".
Under good conditions and if the plant, production is nearly
continuous,, an experienced sampling-team can conduct a perfor-
mance test in one day in"the field (not necessarily 8 hours).
Intermittent plant operation often extends the time'required to
perform 'the test. Although the sampling can be performed in
the rain, asphalt paving can not. Rainy weather can postpone
a test for several days. The observer and test team should' be
prepared for several:days of testing.
7.2.2 Determination of Moisture Content in Stack Gases
At asphalt plants, the moisture content of the stack
gases is dependent on the firing rate of the dryer burner, the
air flow rate through the system, the moisture content of the
cold aggregate feed and the type of control equipment employed.
The moisture content of the stack gases can easily be as
low as 4% or as high as 301.
46
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In the EPA Method 5 sampling train, the water vapor
in the sample stream is collected by the impingers in the,
sampling box. The instruments in the meter box measure only
the flow of. dry sample gases. Therefore to perform isokinetic
sampling, an estimate of the percentage of moisture in the
effluent stream is necessary. Note that the sampler is
interested in the actual percent moisture (absolute humidity),
and not relative humidity. An absolute error of 1% in esti-
mating moisture will generate "a relative error" of approxi-
mately 1% in the sampling rate.
Asphalt plants controlled with baghouses typically have
higher moisture contents in the stack gases than plants
controlled with scrubbers. Baghouses must be maintained above
the dew point to prevent blinding of the filter bags. For
plants equipped with baghouses, the stack temperature usually
ranges from 88°C to 138°C (190-280°F) and the percent moisture
usually falls between 14% and 30%. Plants equipped with wet-
collection devices normally have saturated stack gases but at
a lower stack temperature. Stack temperature is usually within
the range of 32°C to 71°C (90-160°F) and the percent moisture
ranges from 4% to 20%.
The wet bulb, dry bulb method provides the simplest means
of estimating percent moisture. Many stack samplers distrust
this method because it has given them erroneous data. This is
usually due to neglecting to make pressure corrections. To
obtain good results with this method, the sensing portion of
the wet bulb thermometer must be completely covered with a
wetted wick and the wet bulb temperature must be determined
before the wick dries out. A psychrometic chart which corrects
for absolute pressure changes, Figure 7-1, is included for
field estimations.
Wet-collection devices rely on intimate contact between
the dust-laden gases and the scrubber water to collect particu-
late. The effluent from scrubber systems is usually saturated
with water vapor. Under saturated conditions, the wet bulb and
dry bulb temperatures are the same. Often, the stack gases
47
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25-
16-
Z7-
Z8-
59-
Ul
oc
8
3
(1 -
3-
i—SO
-40
-30 °
r°
ui
-200 |
-400 5
-6OO 2
Q£
-800 |
_ Ul
^*
-1000
-1200
20
O
an
*-
VI
-10
Figure 7-1
AIR - WATER VAPOR PSYCHROMETRIC CHART
Conventional psychrometric charts provide values of moisture
content based-on wet bulb and dry bulb temperature measurements,.
but they generally apply only to measurements made at standard
barometric pressure (29.92 inches Hg). The above nomograph
allows you to determine the moisture content for a wide range
of system (or atmospheric) pressures. '
To use the nomograph, line up the absolute pressure of the
system (or atmosphere) with the wet bulb temperature. Where it
crosses the "saturation" line is the value of the moisture
content if the system is saturated with water vapor (i.e., the
dry bulb temperature equals the wet bulb temperature). If the
system is not saturated, line up the saturation moisture
content with the difference between the wet bulb and dry bulb
temperatures, which yields the value for the moisture content
on the far right scale. Example: while testing an asphalt
plant cpntrolled with a baghouse, the following measurements
were made:
Absolute stack pressure - 29.30" Hg.
Dry bulb temperature - 240°F
Wet bulb .temperature 140°F
Then, moisture content at saturation = 20%
moisture content of stack gas = 16%
48
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after scrubber systems will contain entrained liquid droplets.
Consequently, the water collected in the sample box may be
greater than the quantity of water necessary to saturate the
sample gas stream at stack conditions. For this case, assume
saturation and calculate the precent moisture using either
the psychrometric chart [wet bulb + dry bulb temperature] or
saturated steam tables. To use the steam tables, find the
saturated vapor pressure corresponding to the stack tempera-
ture. The fraction of the gas stream which is water vapor
is determined as the ratio of the saturated vapor pressure to
the absolute stack pressure. Under no conditions can the
percent moisture be greater than saturated conditions.
The moisture content of the effluent stream may vary
during the test due to variations in the process. Repeated
checks of the assumed moisture content are necessary to
maintain isokinetic sampling conditions throughout the test.
For sources with saturated effluent, the moisture content
estimation must be changed as the stack temperature changes.
As an example, consider a scrubber controlled plant with
saturated effluent at 29.9 in. Hg., absolute stack pressure.
If the stack temperature changes from 140°F to 150°F, the
moisture content will vary from 19.7% to 25.31. Changes in
moisture content must be considered when calculating isokinetic
sampling rates.
If a standard EPA nomograph is used to set isokinetic
sampling rates, it is usually advantageous to pre-calculate s
a number of C-Factors based on the expected range of moisture
contents. This facilitates rapid adjustments of the sampling
rate during the performance test.
7.2.5 Cyclonic Flow
Cyclonic flow constitutes the most difficult particulate
sampling problem which is encountered at asphalt plants.
Stacks attached to centrifugal inertial demisters following
venturi scrubbers and/or low-energy wet scrubbers and stacks
49
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with tangential inlets are the most common causes of
cyclonic flow at asphalt plants. Many of the stacks with
cyclonic flow at asphalt plants are large diameter stacks
(3.3m, 10 feet). Often these stacks have little straight
run, approximately 2 diameters is typical. These conditions
make modification of the stacks, (straightening vanes and/
or stack extensions) difficult. In addition, many of the
stacks at asphalt plants with cyclonic flow have entrained
water droplets in the effluent. This further complicates
particulate sampling in these stacks.
Appendix D provides a paper which discusses three.
sampling approaches for isokinetic particulate testing in
cyclonic flow systems. The biases associated with each
sampling technique are described. Source modifications
which can be employed are also described.
50
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Chapter VIII
MONITORING PROCESS AND CONTROL SYSTEM PARAMETERS
Monitoring and documenting the appropriate process and
control system parameters during a performance test is important
for several reasons. First, only by monitoring the important
operating parameters during the test can it be determined whether
or not the performance test is conducted at the prescribed
representative conditions agreed upon during the developmental
stages of the test (see Chapter VI). Testing at other than
representative conditions is of little use for determining compliance
with the applicable regulations. Secondly, determining the process
and control system parameters during the performance test estab-
lishes a baseline for future comparison of operating conditions
during follow-up inspections. Such a baseline greatly increases
the effectiveness of follow-up inspections. Finally, for states with
emission standards expressed as the ratio of particulate emissions
to process weight rate, the determination of the process rate
is of fundamental importance. Thus, monitoring the operational
conditions of the source during the performance test is as import-
ant as the actual stack sampling.
8.1 Monitoring the Process
This section details procedures which may be used to
monitor the process rate and conditions.
8.1.1 Process Rate
The process rate may be described in terms of the pro-
duction rate, process weight rate, or the cold aggregate feed
rate. The production rate is the quantity of asphalt concrete
produced per unit of time. The process weight rate is defined
as the sum of all material inputs per unit of time. The production
rate is a sufficient indicator of process rate for tests to de-
termine compliance with NSPS. However, most state regulations
51
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require that the process weight rate be determined. Figure 8-1
provides a schematic diagram of the flow of materials at an asphalt
plant.
Production Rate. Since asphalt concrete ;is sold by weight,
monitoring the production rate is relatively simple. Two
methods may be used to determine produciton rate:
(1) The quantity of asphalt sold is monitored by weighing
each truck. Records of sales are kept by the weigh scale operator.
To determine the production rate, total the amounts of asphalt
loaded into each truck and divide by the length of time the plant,.
was operating. If the plant has heated facilities for storing
the completed product, the quantity of asphalt concrete in storage
must be estimated both before and after the test period.
(2) To ensure that the product complies with mixture speci-
fications, the quantities of the various sizes of aggregate and
of asphalt are controlled by the plant operator. Consult with the
operator to determine the weight per batch. The control panel
contains a batch integrator which counts the number of batches pro-
duced. The production rate is the weight per batch times the.
number of batches, divided by the length of time the plant, was
operating.
Cold Aggregate Feed Rate, the cold aggregate feed rate
can be estimated as the production rate plus the moisture content
of the cold aggregate, minus the amount of asphalt cement added
to the mixture. Usually, both the moisture content and asphalt ce-
ment are approximately 5%. This allows estimation of the cold
aggregate feed as equal to the production rate. Dust loss from
the system can be considered negligible for the purposes of this
estimation. To use this method, the plant should be operating at
steady state conditions (constant level in hot bins). If the
hot bins oyer.flow, an error is introduced. The cold aggregate
feed rate can be measured directly ,by measuring ,the quantity of
aggregate on a section of the feed conveyor and determining the
conveyor speed.
52
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Aggregate Bins
Primary
Collecto
Secondary
Collector
Stack
Screens
Hot Bins
(storage)
Asphalt
Cement
Figure 8-2.. Process Flow Diagram
-------
8.1.2 Aggregate Feed - Size Distribution and Moisture Content
The plant operator can provide the relative quantities of
the various aggregate sizes used in the mixture. These quan-
tities, the amount of asphalt cement used, and the type of mixture
produced should be noted. Since.a large percentage of the fine
material and mineral dust introduced into the dryer is lost in
the processing, the aggregate size distribution should be deter-
mined by sampling the cold aggregate feed.
To sample the aggregate feed, have the plant operator
briefly stop the feed conveyor. Remove all material from a
section across the conveyor and place in a clean, dry, air-tight
container. Repeat this procedure several times. The samples may
be collected in the same container.
Percent moisture is determined by weighing the sample, drying
the sample at 100°C, and again weighing the sample.
percent moisture.- (wet weig^ weig£tWeight) * 100
The size distribution is determined by performing a sieve
analysis. Most plants have the facilities to perform the analysis.
Of particular interest are the relative quantities of fine aggre-
gate (material passing No. 8 mesh seive) and mineral dust (material
passing No. 200 mesh seive). Classification of the aggregate into
several additional grades is sufficient.
8.1.5 Additional Dryer Performance Parameters
1) Hot Aggregate Temperature - usually monitored in plant
operator's control room. Note temperature and location
of measurement device.
2) Dryer Exhaust Gas Temperature - usually monitored in con-
trol room. Note temperature and location of measurement
device.
3) Type of Fuel and Fuel Consumption- The type of fuel used
should be noted. Fuel consumption per hour or per ton of
aggregate should be noted if monitored by the plant or if
easily determined.
54
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4) Damper Position - note or sketch the damper opening if a
damper exists in the dryer exhaust system.
8.1.4 Excess Air
Excess air should be determined at plants where production
capacity is limited by exhaust system capacity or when a plant is
being retested after failing marginally.
A simple procedure exists for determining excess air:
1) Obtain a sampling site (3/8" hole) in the dryer exhaust
duct as close as possible to the dryer exit.
2) Using a 1/4" stainless steel probe, obtain a grab sample
of the combustion gases.
3) Determine the %COj or %02 in the exhaust gases using
either a fyrite or orsat analyzer. (The fyrite is
sufficiently accurate for this measurement and much
easier to use).
4) Referring to Figure 8-2, the amount of excess air can be
determined using either %C09 or %09, and the type of fuel
£* £t
being burned.
8.2 Monitoring Control System Parameters
This section details specific methods which may be used
to determine the important operational parameters for various control
devices.
8.2.1 Pressure Drop
The pressure drop ( Ap) across air pollution control equip-
ment is expressed in height of water column (mm or inches). The
pressure drop across a control device can be measured directly as
shown in Figure 8-3. The upstream side is always higher pressure.
If the inlet and outlet cannot be reached simultaneously,
the pressure differences between the inlet and the atmosphere
(Ap^) and between the outlet and the atmosphere (AP0) may be
determined separately as shown in Figure 8-4. The pressure drop
is then: Ap = Ap. - Ap
55
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ENTROPY ENVIRONMENTALISTS INC.
1500-1
in, *£oaita»
Example: Known: 240% excess air burning Pentane
Answer: 15%
— 1
& 4% CO in flue gas
— 2
— 3
— 4
Q
5 g
6 *
_ 8
8 *'
-10
15
20
Refuse,' Bark -
and Wood
— Methane
_ Average Natural Gas
— Ethane
—. Propane
— Pentane
— Gasoline.
- #2 Fuel Oil
Bunker,."C" Oil
(#6 Fuel Oil)
- Bituminous Coal
" T-Sub-bituminous & Lignite
F Anthracite
Coke
NOMOGRAPH FOR ESTIMATING FLUE GAS COMPOSITION,
EXCESS AIR OR TYPE OF FUEL
Figure 8-2
56
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Inlet
Collection
Device
High
T.nw
(&
Gage
Ap
Figure :g-3
Collection
Device
Outlet
Gage
Ap = Ap • ~ Ap
Figure 8-4
MEASUREMENT OF STATIC PRESSURE DROP - Ap
57
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If the exhaust fan is before the collector, then both the inlet
and outlet duct pressures will be higher than or equal to at-
mospheric pressure (positive). If the exhaust fan is after the
collector, the inlet and outlet duct pressures will be lower than
atmospheric pressure (negative).
To obtain accurate static pressure measurements, the pressure
probe must be perpendicular to the direction of flow. The probe
and connecting tubing must be kept free of dirt and moisture.
Be careful to connect the high pressure side of the gage to the
high pressure source and not to exceed the range of the instrument.
When using manometers, make sure the gage is level and zeroed.
Spare gage fluid is often handy due to the large pressure drops
across some devices, which can blow the fluid out of the instrument,
8.2.2 Cyclones - Multicyclones
The pressure drop, cyclone diameter, and, when multicyclones
are used, the number of collectors should be determined.
8.2.3 Baghouses
The pressure drop across" the baghouse should be determined.
If the pressure drop varies during the cleaning cycle, then the
range of fluctutation should also be noted.
The cleaning cycle frequency should, be determined. The
plant operator usually controls the cleaning cycle frequency from
the control room. Note the setting on the cleaning timer. If
the cleaning cycle is automatically controlled by a pressure
sensing device, the pressure setting should be noted if it is
available.
The area o.f the filter cloth can sometimes be determined by
checking the baghouse nameplate or by referring to the state
permit. If not available, the observer should request the plant
official to furnish or obtain the effective cloth area from the
manufacturer.
58
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8.2.4 Wet-Collection Devices
The operating parameters which are important for most
wet-collection devices are pressure drop, water flow rate, and
water pressure.
The pressure drop across venturi scrubbers and across each
component in multiple scrubber systems must be measured.
For venturi scrubbers with adjustable throats, the throat
opening should be measured. When this is physically impossible,
the position of the adjustments should be permanently marked as
a reference for future site inspections. Some orifice scrubbers
used in low-energy systems have adjustable orifice openings either
mechanically adjusted or dependent on the water level in the
device. An attempt should be made to measure or mark the size
of the opening.
Water Flow Rate. Measurement of water flow rate presents
several problems. Very few plants are equipped with water flow
meters on the scrubber equipment. The plant owner may be
required to install equipment to measure water flow under 40 CRF
60.8e; however, such an action may be of questionable effective-
ness. Some plants equipped with low-energy wet-collectors have
multiple water pumps and supply lines, thus requiring several flow
meters which may constitute a considerable expense. Scrubber water
is almost always recycled through a settling pond. The scrubber
water can contain a significant amount of solid particles (silt)
which can lead to the rapid deterioration of flow measuring
device. If flow devices are installed, they must be cleaned and
calibrated periodically. Flow measuring devices should be in-
stalled as shown in Figure 8-5. This permits removing the
instrument from the flow steam when not in use. This set-up
reduces the frequency of cleaning and calibration and increases
the life of the meter. Either a flow rate meter or quantity
totalizing meter and stopwatch can be used to determine the flow
rate.
59
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Valves
Figure 8-5. Flow Meter Installation
Gage
Figure 8-6
Pressure Gage Installation
60
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The water flow rate can sometimes be determined by ob-
serving the water discharge from the scrubber system. If the
discharge pipe is horizontal and above the surface, the following
method is applicable:
•Discharge Pipe
. .X.
• . X
. '. N. •
X • \
\ V
\ •. -
-x- \
I. Measure the distance (x) between a point P (located one
foot below pipe centerline) and the center of the discharge
stream.
2. Determine the cross-sectional area (A) of flow leaving dis-
charge pipe (if pipe is full, then pipe exit area is used).
3. Calculate the water discharge rate (Q) as:
Q (m3/min) =240 • A (m2) ' x(m)
. Q (gal/min) = 1800 ' A(ft2) ' x(ft)
A relative measure of water flow rate can be made by measuring
the speed (rpm) of the water pump or pump drive. At a constant
delivery pressure, the flow rate is directly proportional to the
pump speed.
Water Pressure. Some plants have water pressure gages
on the scrubber supply lines, particularly the water lines which
feed spray systems. These gages are often broken or filled with
dust and silt. The following procedures are recommended for checking
existing pressure gages:
61
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1. Check general condition of the gage. Look for possible
contamination by ambient dust.
2. Turn off water supply, or if gage is equipped with valves,
isolate and drain water from gage. Check gage zero.
3. Turn on water supply and note gage reading, drain gage and
repeat. Gage should read consistently.
Gages which are contaminated with dust or silt generally
indicate less than real pressure. Gages which do not zero cor-
rectly or do not read consistently should be removed and cleaned,
and replaced if necessary. When new gages are required, they should
be installed as shown in Figure 8-6. When not in use, the
proper gage should be isolated and drained by operating the
proper valves.
On spray systems, it is important to check to see if all
nozzles are clear. High delivery pressure is not necessarily
indicative of proper operation for spray nozzles.
8:3 Additional System Parameters
This section applies to the operational variables which
concern the combined system of plant and control equipment. A
method to determine the amount of dilution air added to the
system, a method for determining the flow rate at different points
in the system, and several methods fo'r estimating' the system
volumetric flow rate are provided.
8.3.1 Dilution Measurements --, Local Flow-Rate Determinations
The procedures outlines in this section should be utilized
when: 1) insufficient flow in the scavenger system is suspected',
2) the production rate is lower than expected and the plant oper-
ator claims that production is limited by dryer exhaust capacity,
3) when dilution air is added to the system and the applicable
emission regulation is expressed in terms of concentration.
To determine (1)> the amount of leakage or dilution air added
to the system,(2), the flow rate at any point in the system, or
(3),the flow rate through the scavenger system,the following
procedures are applicable:
62
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Consider the flow diagram shown below:
Baghouse
scavenger
system
Cyclone
The volume flow rate, Qz (dscfm), and the % CO-
at the stack(point 3) are measured in the course of a per-
formance test. If the ICO~ at several other points is determined,
then the quantity of air added to the system between these points
and the flow rate at these points can be determined. For example,
if I C02 is known at points 1, and 2, then:
(1) the flow rate at point 2 is Q2 = Q3
ICO,
ICO,
'(dscfm)
(2) the air leakage between points 2 and 3 is
Leakage Air (dscfm) = Q3-Q2 = Q
Similarly, the flow rate at point 1 is :
ICO,
1 -
ICO
2 (2)
(3) Q1(dscfm) = Q2 x
ICO
2 (2.
ICO,
ICO
= Q- x
2 I
ICO,
and the flow rate in the scavenger system is :
1 -
ICO,
ICO
2 1
ICO,
ICO-
2 (2
1 -
ICO,
ICO,
Note: The values of Q, volumetric flow rate, in the above equations, must be
expressed at dry standard conditions (dscfm). To calculate the volume flow
rate at actual conditions, use the equation:
Q acfm = Q (dscfm,
100
29.92
460
where: %H20 = moisture content of gas stream, volume percent
T = absolute gas temperature (R°)
P = absolute gas pressure (in Hg.)
63
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To determine the flow rate at the actual conditions, the
percent moisture, gas temperature and gas pressure must be
measured. The volume percent moisture is most easily determined
by using the wet bulb, dry bulb method and psychrometric nomo-
graph which is included in section 6.4.1. These procedures assume
that the leakage air and scavenger system air contain negligible
C0_. The method does not apply if leakage out of the system
occurs. Also, this procedure should not be used after a wet-
collection device since the water can absorb a portion of .the
CO., and the moisture content of the gases will change.
£* '
8.3.2 Air Flow Measurements
During a performance test, the volumetric flow rate is
measured. Measuring certain system parameters during the per-
formance test provides methods of estimating the flow rate during
subsequent site inspections. Several procedures are applicable.
Method 1 - Cyclone Pressure Drop
The pressure drop across a cyclone or multicyclone is related
to the flow rate _by:
kO P/o
Ap = • "• t where: Ap = cyclone pressure drop
T
k = proportionality constant
Q = volumetric flow rate
P - absolute gas pres'sure
T = absolute gas temperature
/? =. gas density
If the pressure, density and temperature are assumed to be
constant for similar operating conditions, then Q= F -^Ap and
F is a new proportionality constant. Measuring Q and Ap during
the test allows determination of F. The value of F and the
pressure drop .across the cyclone can be used to estimate the flow
rate during future site inspections if relatively consistent
process conditions are maintained.
Method 2- Fan Speed
Exhaust fans used at 'asphalt plants are essentially constant
volume devices. Volumetric flow rate through the fan varies directly
with the fan speed. It is important to recognize that although
64
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the volume flow rate is constant at cons±ant speed, the mass flow
rate is dependent on the temperature, pressure, and density of the
gas stream.
The fan speed can be determined using a hand-held tachometer.
Access through the belt guard to the fan shaft must be provided.
Caution should be used in applying this method since
erosion of the fan blades by the entrained dust will affect the
flow rate to speed relationship. This is particularly important
if the fan is located before the secondary control device. This
method should not be used if the exhaust fan serves as a wet-fan
in a scrubber system, since blade wear can be expected.
Method 5 - System Pressure Drop
The system pressure drop is the sum of all the pressure drops
across the individual components of the air handling system (dryer,
ductwork, damper, and control devices). Since the dryer inlet and
the stack are open to the atmosphere, the algebraic sum of the
system pressure drop and the increase in static pressure across
-the exhaust fan must be equal to zero. It is much easier to
measure the pressure rise across the fan than summing the in-
.dividual pressure drops. If the system resistance to flow is
•constant, the static pressure rise across the fan is directly pro-
portional to the square of the volume flow rate through the system.
The static pressure rise across the fan can be measured
using the procedures given in section 6.6.1. Obviously, the fan
outlet pressure is always greater than the inlet pressure.
Caution should be exercised in interpreting fan pressure
rise data ,since the pressure rise will also change with any change in the
flow resistance at a constant flow rate.
65
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Chapter IX
VISIBLE EMISSION OBSERVATIONS
Alone, opacity measurements constitute an enforceable
emission standard for both Federal and State regulations. The
opacity of emissions must be determined in accordance with EPA
Method 9 by a certified observer. (A copy of Method 9 'is
included in Appendix B of this report). At asphalt plants,
visible emission observations should be conducted at all
emission points including the rotary dryer, fugitive-dust
control system, and the stack. The appr.opriate.-data should., be
recorded on the "Opacity Observation, Form" which is .-included
in Appendix C of this report.
Stack emissions from asphalt plants .equipped with scrubber
systems are normally .accompanied by extensive attached sjteam
plumes. Asphalt plants controlle.d with b.aghouses usually
have detached steam plumes although .attached plumes ar.e some-
times encountered.-For attached steam plumes, Method. 9; requires
that opacity observations are made beyond,the point in- the
plume where the water vapor .is no longer visible. .The observer
must record the distance from the .stack, outlet, to the;, point in
the plume where observations are made.. In some cases,
condensed water vapor is visible in the,plume, several hundred
feet from the stack outlet. Since the plume dissipates., with
distance, visible emissions are at best very difficult, in,
these instances.
Opacity readings of stack emissions during performance
tests (where the mass emission rate is accurately measured),
provide a valuable baseline for comparison of visible emission
observations during subsequent follow-up inspections.
A considerable amount of data exists which indicates
that asphalt plants meeting the NSPS particulate emission stand-
ard (90 mg/dscm or 0.04 gr/dscf) have virtually no visible
66
-------
emissions. Some success has been obtained with mass emission
opacity correlations at asphalt plants. Further research is
required before the results of these correlations can be
applied to asphalt plants in general. Additional information
on these correlations will be included in the final report.
67
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Chapter X
REVIEW AND EVALUATION OF PERFORMANCE TEST REPORTS
An importance task for the enforcement agency, once a
performance test has been conducted, is the review and evaluation
of the test report. Detailed procedures for reviewing test
reports are provided in Volume III - Development, Observation.
and Evaluation of Performance Tests.
10.1 Review of Test Reports
Copies of the test protocol, the "Observer's Report",
the "Observer's Sampling Checklist", the "Observer's Process and
Control System Data Form" and any other applicable information,
such as state permits, should be obtained before reviewing the
actual test report. The test report must be examined both for
completeness in reporting all the pertinent sampling and process
data and for accuracy in the calculation procedures used to deter-
mine the emission rate. All sampling reports should contain copies
of the original field sampling data. Computer printouts of the
raw field data are unacceptable since there is no way to determine
if the information was correctly entered into the computer. A
check on the accuracy of the calculated emission rate is accom-
plished by simply recalculating the emission rate using only the
raw field data and laboratory analytical results. The percent
isokinetic, (%I), should also be calculated from the test data.
Tests where II is between 90% and 110% are acceptable. Volume
V,Development, Observation, and Evaluation of Performance Tests,
provides criteria or. accepting or rejecting tests outside the
normal acceptable isokinetic range.
The process and control system information contained in the
test report and the information on the "Observer's Process and
Control System Data Form" should be reviewed to determine if the
test was conducted at the representative conditions specified in
currently being prepared by the Division of Stationary Source
Enforcement, U.S. EPA.
68
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Source Testing Report Format
Cover
1. Plant name and location
2. Source sampled
3. Testing compnay or agency, name, and address
Certification
1. Certification by team leader
2. Certification by reviewer (e.g., P.E.)
Introduction
1. Test purpose
2. Test location, type of process
3. Test dates
4. Pollutants tested
5. Observers' names (industry and agency)
6. Any other important background information
Summary of Results
1. Emission results
2. Process data, as related to determination of compliance
3. Allowable emissions
4. Description of collected samples
5. Visible emissions summary
6. Discussion of errors, both real and apparent
Source operation
1. Description of process and control devices
2. Process and control equipment flow diagram
3. Process data and results, with example calculations
4. Representativeness of raw materials and products
5. Any specially required operation demonstrated
Sampling and Analysis Procedures
1. Sampling port location and dimensioned cross section
2. Sampling point description, including labeling syste-
3. Sampling train description
4. Brief description of sampling procedures, with discussion
of deviations from standard methods
5. Brief description of analytical procedures, with discussion
of deviations from standard methods
Appendix
1. Complete results with example calculations
?. Raw field data (original, not computer printouts)
3. Laboratory report, with chain of custody
4. Raw production data, signed by plant official
5. Test log
6. Calibration procedures and results
7. Project participants and titles
8. Related correspondence
9. Standard procedures
69
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the test protocol. In short, if the test was conducted at
representative conditions, if all sampling procedures which were
used are acceptable, if the test report is complete and accurate
(both data and calculations), then the performance test is ac-
ceptable. Determination of compliance is based on the average
emission rate for the three sampling runs.
10.2 Checking Test Data
The following paragraphs describe methods which may be
used to crosscheck sampling data included in the performance test
report.
Barometric Pressure: Incorrect barometric pressure measure-
ment will not generally cause errors of more than 10-15%, but it
is a very common error. The value reported by the tester can be
checked in.two separate ways. First, the value reported should
be reasonable, with respect to the elevation at the plant site.
At sea level, the barometric pressure is almost always between
29 and 31 inches of mercury, and usually close to 30. For every
1000 feet above sea level, the value will decrease 'by 1.1 inches
of mercury. As. a more accurate check, the reviewer can call
r" ' . . ' ' '
the airport closest to test site, and ask for the "station"
pressure (not corrected to sea level) for the date of the test.
Stack Pressure: Since almost all sampling at asphalt plant
is conducted near the exit of the stack, the stack pressure
should be essentially the same as, or slightly less than, at-
mospheric pressure.
Stack Temperature: The stack temperature for plants controlled
by baghouses typically ranges from 88°C to 138°C (190-280°F).
In any case, the stack temperature is approximately the same as the
baghouse temperature, which must be maintained above the dew
point. This provides a lower limit for the stack temperature.
An upper limit for the stack temperature is provided by the dryer
exhaust temperature. For asphalt plants controlled by wet-
collection devices, the stack temperature normally ranges from
90°F to 160°F.
70
-------
Dry Molecular Weight: The dry molecular weight of the stack
gases at asphalt plants typically ranges from 29.0 to 29.5 due to
the high excess air and dilution by the scavenger system.
The orsat data can be checked by using Figure 8-2. Data
reported by aligning the type of fuel with the fcCO? and I02
can be checked by aligning the type of fuel with the % CC^ and
checking the 102 from the nomograph with the reported value.
The reviewer is cautioned that if the orsat data was taken after
a scrubber, the nomograph may not work, since the scrubber will
remove an indeterminate amount of carbon dioxide.
Leak Tests: Leak tests are required after each sample run
and prior to filter changes during the run. Most testers also
perform leak tests immediately prior to each sample run. The
observer should have witnessed each leak test and recorded the leak-
age rate on the "Observer's Sampling Checklist". If the observer
failed to record leakage rates and the report claims that leak
tests were performed, either after each test or before filter
changes, the dry gas meter readings on the data sheet would indi-
cate this. In other words, it is unlikely that a leak test was
done after run #1 if the final volume reading for run #1 is the
same as the initial volume reading on run #2. If a leak test
was made in the middle of the run (because of a filter change, for
example), the volume readings before and after the leak test
would be shown on the data sheet, so that the computed meter volume
could be adjusted accordingly.
If the sampling train fails to meet the acceptable leakage
rate criteria, (.57 1/min, .02 cfm), then the tester has the
option to subtract the product of the measured leakage rate and
the duration of the test from the sample volume or repeat the test.
Adjusting the sample volume for an excessive leakage rate intro-
duced a high bias (in the agency's favor) in the calculated
emission rate.
71
-------
Sample Volume: The sample volume should be checked by
referring to the initial and final dry gas meter readings re-
corded on the "Observer's Sampling Checklist". Any discrepancies
between the values given by the observer and the test report
must be resolved. '
Moisture Data: There are several procedures which may be
used to check moisture data. The first check is to compare the
assumed moisture content recorded on the field data sheet or
"Observer's Sampling Checklist" to the actual measured value.
Normally, an absolute error of 1% in estimating the moisture
content of the stack gas (It^O actual - IH20 estimated) will
introduce a relative error of approximately 1% in the sampling
rate. Thus isokinetic sampling conditions will be off by 1%.
The stack gases at asphalt plants controlled "by scrubbers
are normally saturated.with water vapor and may contain en-
trained water,droplets., .Entrained droplets of liquid water in
the stack gases can yield an erroneously.high moisture content.
All moisture data should be che.cked (even if there are no entrained
water droplets) to ensure that the reported' value is not higher
than the saturation moisture content. Figure 10-1 gives the
moisture content at saturation as a function of stack absolute
pressure and stack gas, temperature (at saturation 'conditions,
the wet bulb temperature is equal to the 'dry'bulb temperature).
If. the reported value is higher than the maximum shown in Figure
10-1, the data is suspect. Generally, if the high reading was
caused by entrained water droplets, the value is adjusted to the
saturation moisture content. r
At asphalt plants.controlled by baghouses, a water balance
across the process may be used to check both moisture data and
process data if sufficient information is available. The mass
balance requires determination of the volumetric flow rates (dscfm)
at the stack and dryer exit. A method for determining these
values is provided in section 8.3.1. The type of fuel used,
72
-------
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31 -
32-
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AIR - WATER VAPOR PSYCHROMETRIC CHART
-------
excess air at dryer exist (section 8.1.4), cold aggregate feed
rate and percent moisture in the aggregate feed must also be
known.
The mass rate of water leaving the stack, A, is:
lb H70 !H90 - A
A C —) = Q stack (dscfm) (— ) (.0456)
min 100 - %H20
where the %H20 - A is the percent moisture of the stack gases
given in the report.
The mass rate of water supplied by the ambient air, B, is
approximately: lb „ Q %H,0 - B
(B ±- )= Q stack (dscfm) ( . ) (.0467)
min 100 - %H0
where the %H70 - B is the percent moisture.in .the ambient air,
determined from Figure: 10-2.
The mass rate of water supplied by combustion of the fuel,
C, is:
lb H70 IH-0 - C
C (———) = Q dryer(dscfm) (-^- ) (.04-67)
min 100 - H0
where the ..%H70 - (T is the percent moisture from the combustion
of the fuel, determined from Figure 10-3.
The mass rate of water supplied by the aggregate, D, is:
lb H20
D( —) = %H20 x aggregate feed rate (rfpfr) x 33.3
min °° nour
where the percent moisture in the aggregate is determined by the
procedure given in section 8.1.2. A mass balance of the water
requires that: A = B + C + D
74
-------
10 —I
I—0
— 50
X
a
a
U
•100
MOISTURE FROM THE AMBIENT AIR
Figure 10-2
•
M
<
m
U)
u
u
X
H
*
— 0
•
• 7!
O
; «
c- 50 *• >•
r•.
" ,
•
- 0.5
,
I SKS'.-HStur.l Ga.
. Propane
. Gasoline
. «2 Fuel 01-1
. Bunker "C" oil
J
• Bituminous Coal
f
.
1 Subbituninoua and
J Lignite
• Anthracite
—i
-Coke
FOB DETERMINING MOISTURE U) FLUE GAS
FROM COMBUSTION OF FUEL
Figure 1O3
75
-------
Volume Flow Rate: The volumetric flow rate is difficult
to cross-check. Normally, 185 to 315 scm/metric ton of product
(6000 - 10,000 scf/ton) is typical. However, values as high
as 470 scm/metric ton (15,000 scf/ton) are sometimes encountered.
Miscellaneous Data: The data provided by the sampling report
should be consistent with values listed on the "Observer's
Sampling Checklist",
76
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APPENDIX A
NSPS REGULATIONS
; 60.8 IVrformjiiirr IcMs.
R i Wi .hin 60 days after achieving the
maximum production rate at which the
affected facility will'be oi>erated. but not
alcr than 180 days after initial startup
of such facility and at such other times
as may be required by the Administrator
under section '114 of the Act, the owner
or operator of such facility shall conduct
>erformance test's) and furnish the Ad-
ministrator a written report of the results
of such performance test (s >.
(b) Performance tests shall be con-
ducted and data reduced in accordance
with the test methods and procedures
contained In each applicable subpart
unless the Administrator (1) specifies
or approves, in specific cases, the use of
a reference method with minor changes
in methodology. (2) approves the use
of an equivalent method, (3) approves
the use of an alternative method the re-
sults of which he has determined to be
adequate for indicating whether a spe- •
cific source is in compliance, or (4)
waives the requirement for performance
tests because the owner or operator of
a source has demonstrated by other
means .to the Administrator's satisfac-
tion that the affected facility is in com-
pliance with the standard. Nothing in
this paragraph shall be construed to
abrogate the Administrator's authority
to require testing under section 114 of
the Act.
The owner or operator of ar.
affected facility shall provide the Ad-
ministrator 30 days prior notice of the
performance test to aflord the Admin-
istrator the opportunity to have an ob-
server .present.
>e> The owner or operator of ar.
affected facility shall provide, or cause 10
be provided, performance testing facil-
ities as follows:
.il > Sampling ports adequate for tes:
methods applicable to such facility. .
<:> Safe sampling platform 151.
'3> Safe -access to sampling plat-
form Utilities for sampling and test;r.£
equipment.
-------
Appendix B
EPA TEST METHODS FOR ASPHALT CONCRETE PLANTS
Method 1
Method 2
Method 3
Method 5
Method 9
-------
41754
RUIES AND REGULATIONS
TWe 40—Protection of Environment
CHAPTER I—ENVIRONMENTAL
PROTECTION AGENCY
[PHI. 754-5]
PART 6O—STANDARDS OF PERFORM-
ANCE FOR NEW STATIONARY SOURCES
Revision to Reference Methods 1-8
AGENCY: -environmental Protection
Agency.
ACTION: Final Rule.
SUMMARY: This rule revises Reference
Methods 1 through 8. the detailed re-
quirements used to measure emissions
from affected faculties to determine
whether they are In compliance with a
standard of performance. The methods
were originally promulgated December
23. 1971. and since that time several re-
visions became apparent which would
clarify, correct and Improve the meth-
ods. These revisions make the methods
easier to use. and improve then* accuracy
and reliability.
EFFECTIVE DATE: September 19,1977.
ADDRESSES: Copies of the comment
letters are available for public Inspection
and copying at the U.S. Environmental
Protection Agency. Public Information
Reference Unit (EPA Library), Room
2922. 401 M Street. S.W., Washington.
D.C. 20460. A summary of the comments
and EPA's responses may be obtained
upon written request from the EPA Pub-
lic information Center (PM-215), 401
M Street. S.W.. Washington, D.C. 20460
(specify "Public Comment. Summary:
Revisions to Reference Methods 1-8 In
Appendix A of Standards of Performance
.for New Stationary Sources").
FOR PUUTHKU INFORMATION CON-
TACT:
Don R. Goodwin, Emission Standards
and Engineering Division, Environ-
mental Protection Agency, Research
Triangle Park. North Carolina 27711,
telephone No. 919-541-5271.
SUPPLEMENTARY INFORMATION:
The amendments were proposed on June
8, 1976 (40 FR 23060). A total of 55 com-
ment letters were received during the
comment period—34 from Industry, 15
from governmental agencies, and 6 from
other Interested parties. They contained
numerous suggestions which were incor-
porated in the final revisions.
Changes common to all eight of the
reference methods are: (1) the clarifica-
tion of procedures and equipment spec-
ifications resulting from the comments,
(2) the addition of guidelines for al-
ternative procedures and equipment to
make prior approval of the Administra-
tor unnecessary and (3) the addition of
an introduction to each reference meth-
od discussing the general use of the
method and delineating the procedure
for using alternative methods and equip-
ment.
Specific changes to the methods are:
METHOD 1
1. The provision for the use of more
than two traverse diameters, when spec-
ified by the Administrator, has been
deleted. If one traverse diameter Is hi a
plane containing the greatest expected
concentration variation, the intended
purpose of the deleted paragraph will be
fulfilled.
2. Based on recent data from Fluidyne
(Participate Sampling Strategies for
Large Power Plants Including Nonunl-
form Flow. EPA-600/2-76-170. June
1976) and Entropy Environmentalists
(Determination of the Optimum Number
of Traverse Points: An Analysis of
Method 1 Criteria (draft), Contract No.
68-01-3172). the number of traverse
points for velocity measurements has
been reduced and the 2:1 length to width
ratio requirement for cross-sectional lay-
out of rectangular ducts has been re-
placed by a "balanced matrix" scheme.
3. Guidelines for sampling In stacks
containing cyclonic flow and stacks
smaller than about 0.31 meter In diam-
eter or 0.071 m* hi cross-sectional area
will be published at a later date.
4. Clarification has been made as to
when a check for cyclonic flow is neces-
sary; also, the suggested procedure for
determination of unacceptable flow con-
ditions has been revised.
METHOD 2
1. The calibration of certain pilot tubes
has been made optional. Appropriate con-
struction and application guidelines have
been included.
2. A detailed calibration procedure for
temperature gauges has been Included.
3. A leak check procedure for pilot
lines has been included.
METHOD 3
1. The applicability of the method has
been confined to fossil-fuel combustion
processes and to other processes where It
has been determined that components
other than O,, CO,, CO. and N. are not
present in concentrations sufficient to
affect the final results.
2. Based on recent research informa-
tion (Particulate Sampling Strategies for
Large Power Plants Including' Nonuni-
form Flow, EPA-600/2-76-170, June
1976), the requirement for proportional
sampling has been dropped and replaced
with the requirement for constant rate
sampling. Proportional and constant rate
sampling have been found to give essen-
tially the same result.
3. The "three consecutive" require-
ment has been replaced by "any three"
for the determination of molecular
weight, CO, and O,.
4. The equation for excess air has been
revised to account for the presence of CO.
5. A clearer distinction has been made
between molecular weight determination
and emission rate correction factor
determination.
6. Single point, Integrated sampling
has been included.
METHOD 4
1. The sampling time of 1 hour has
been changed to a total sampling time
which will span the length of time the
pollutant emission rate Is being deter-
mined or such time as specified in an
applicable subpart of the standards.
.2. The requirement for proportional
sampling has been dropped and replaced
with the requirement for constant rate
sampling,
3. The leak check before the test run
has been made optional; the leak check
after the run remains mandatory.
MXTROD 5
1. The following alternatives have
been Included hi the method:
a. The use of metal probe liners.
b. The use of other materials of con-
struction for filter holders and probe
liner parts.
c. The use of polyethylene wash bot-
tles and sample storage containers.
d. The use of deslccants other than
silica gel or calcium sulfate, when
appropriate.
e. The use of stopcock grease other
than sflicone grease, when appropriate.
f. The drying of filters and probe-niter
catches at elevated temperatures, when
appropriate.
g. The combining of the filler and
probe washes into one container.
2. The leak check prior to a test run
.has been made optional. The post-test
leak check remains mandatory. A meth-
od for correcting sample volume for ex-
cessive leakage rates has been included.
3. Detailed leak check and calibration
procedures for the metering system have
been included.
METHOD 6
1. Possible interfering agents of the
method have been delineated.
2. The options of: (a) using a Method
8 Impinger system, or (b) determining
SOi simultaneously with particulato
matter, have been Included In the
method.
3. Based on recent research data, the
requirement for proportional sampling
has been dropped and replaced with the
requirement for constant rate sampling.
4. Tests have shown that isopropanol
obtained from commercial sources oc-
casionally has peroxide impurities that
will cause erroneously low SO, measure-
ments. Therefore, a test for detecting
peroxides hi isopropanol has been in-
cluded hi the method.
5. The leak check before the test run
has been made optional; the leak check
after the run remains mandatory.
6. A detailed calibration procedure for
the metering system has been included
in the method.
METHOD 7
1. For variable wave length spectro-
photometers, a scanning procedure for
determining the point of maximum ab-
sorbance has been Incorporated as an
option.
METHOD 8
1. Known interfering compounds have
been listed to avoid misapplication of
the method.
2. The determination of filterable
particulate matter (Including acid mist)
simultaneously with SO, and SO, has
been allowed where applicable.
3. Since occasionally some commer-
cially available quantities of isopropanol
FEDERAL REGISTER, VOL 42, NO. 160—THURSDAY, AUGUST 13, 1977
-------
RULES AND tEMULATIONS
41755
have peroxide impurities that wffl cause
erroneously high sulfuric add mist meas-
urements, a test for peroxides In Isopro-
panol has been Included In the method.
4. The gravimetric technique for mols-.
ture content (rather than volumetric)
has been specified because a mixture of
Isopropyl alcohol and water will have a
volume less than the sum of the volumes
of Its content.
5. A closer correspondence has been
made between similar parts of Methods
8 and 5.
MISCELLANEOUS
Several commenters questioned the
meaning of the term "subject to the ap-
proval of the Administrator" in relation
to using alternate test methods and pro-
cedures. As defined In § 60.2 of subpart
A, the "Administrator" Includes any au-
thorized representative of the Adminis-
trator of the Environmental Protection
Agency. Authorized representatives are
EPA officials in EPA Regional Offices or
State, local, and regional governmental
officials who have been delegated the re-
sponsibility of enforcing regulations un-
dergo CFR 60. These officials in consulta-
tion with other staff members familiar
with technical aspects of source .testing
will render decisions regarding accept-
able alternate test procedures.
In accordance with section 117 of the
Act, publication of these methods was
preceded by consultation with appropri-
ate advisory, committees, Independent
experts, and Federal departments and
agencies.
(Sees. Ill, 114 and 301 (a) of the Clean All
Act. aec. *(») of Pub. L. No. 91-604. 84 8tat
1683; >ec. *(») of Pub. U No. 91-604, 84 Stat.
1687; sec. 2 of Pub. L. Mo. 00-148, 81 Stat. 504
142 U.S.C. 18670-6, 1857C-9. 1857g(»)J.)
NOTE.—The Environmental .Protection
Agency has determined that this document
does not contain a major proposal- requiring
preparation of an Economic Impact Analysis
under Executive Orders 11821 and 11949 and
OMB Circular A-107, ' ..
Dated: August 10,1977.
DOUGLAS M. COSTLE,
Administrator.
Part 60 of Chapter I of Title 40 of the
Code of Federal Regulations Is amended
by revising Methods 1 through 8 of Ap-
pendix A—Reference Methods as
follows:
APPENDIX A— REFERENCE' METHODS
The reference methods in this appendii are referred to
in J60.8 (Performance Tests) and 160.11 (Compliance
With Standards and Maintenance Requirements) of 40
CFR Part 60, Subpon A (General Provisions). Specific
uses of these reference methods are described in the
standards of perforniam-e contained iu the subparts,
beginning with Subpart l>.
Within each standard of performance, a section titled
"Test Methods and Procedures" is provided to (1)
identify the test methods applicable to the facility
subject to the respective standard and 12.1 identify any
special instructions or conditions to be followed when
applying a method to the respective facility. Sucb in-
structions (for eiample, establish sampling rates, vol-
umes, or temperatures) are to be used either in addition
to, or as a substitute for procedures in a reference method.
Similarly, for sources subject to emission monitoring
requirements, specific instructions pertaining to any use
of a reference method arc provided in the subpart or in
Appendii B.
Inclusion of methods In this appendli b not Intended
M mn endorsement >or denial of their applicability to
BomcM that •mint subject to standards of performance.
The methods weyotentlany applicable to other sources:
however, applicability should be confirmed by careful
and appropriate evaluation of the conditions prevalent
at such sources.
The approach followed In the formulation of the ref-
erence methods Involves specifications for equipment,
procedures, and performance. In concept, a performance
specification approach would be preferable In all methods
because this allows the greatest flexibility to the user.
In practice, however, this approach Is Impractical in most
cases because performance specifications cannot be
established. Most of the methods described herein,
therefore, Involve specific equipment specifications and
procedures, and only a few methods in this appcndii rely
on performance criteria.
Minor changes In the reference methods should not
necessarily affect the validity of the results and it is
recognized that alternative and equivalent methods
esist. Section 60.8 provides authority for the Administra-
tor to specify or approve (1) equivalent methods, (2)
alternative methods, and (3) minor changes In the
methodology of the reference methods. It should be
clearly understood that unless otherwise identified all
such methods and changes must have prior approval of
the Administrator. An owner employing such methods or
deviations from the reference methods without obtaining
prior approval does so at the risk of subsequent disap-
proval and retesting with approved methods.
Within the reference methods, certain specific equip-
ment or procedures are recognized as being acceptable
or potentially acceptable and are specifically Identified
In the methods. The items identified as acceptable op-
tions may be used without approval but mist be identi-
fied In the test report. The potentially approvable op-
tions are cited as "subject to the approval of the
Administrator" or as "or equivalent." Such potentially
approvable techniques or alternatives may be used at the-
discretion of the owner without prior approval. However.
detailed descriptions (or applying these potentially
approvable techniques or alternatives are cot provided
In the reference methods. Also; the potentially approv-
able options are not necessarily acceptable in all applica?
tions. Therefore, an owner electing to use such po-
tentially approvable techniques or alternatives-is re-
sponsible, for: (1). assuring that the-techniques or
alternatives are' in fact applicable and are properly
executed; (2) Including a written description of the
alternative method: In the test report (the written.
method must be clear and most be capable of .being per-
formed without additional instruction, and the'degree
of detail should be similar to the detail contained in the
reference methods); and (3) providing any rationale or
supporting data necessary to show the validity of Jhe
alternative.in the particular application. 'Failure to
meet these requirements can result in the Adminis-
trator's disapproval of the alternative.
JlETnoD 1—SAMPLE AKD VELOCITY TRAVERSES TOE
STATtONABT SOCEIES
1. rrinciflt and Applicability
.. r.l' Principle. To aid in the reprr-s.-maiivo measure-
ment of pollutant emissions and/or total volumetric flow
' rate from a stationary source, a measurement site .where
the effluent stream is'fiowing in a known direction is
selected, and the cross-section of the stack is divided Into'
a number of equal areas. A traverse point is then located <
within each of these equal areas.
1.2 Applicability. This method is ari|)l:i:aule to flow-
ing gas streams in ducts, stacks, and Hues. The method'
•cannot be used'whcu: (1) flow is cvcloiiic or swirling (see
Section 2.4), (2) a stack Is smaller"thni about 0.30 mewr
(12 in.) in diameter, or 0.071 m" (113 in:1) in cross-ser-
tional area, or. (3) the measurement site-is less than' two
stack or duct diameters downstream or less than a bait
djameter upstrc-am from a flow disturL'an'.v.
The requirements of this method must be considered
before construction of a new facility from which emissions
will be measured; failure to do so may require subsequen t
alterations to the stack or deviation from the standard
procedure. Cases involving variants are subject to ap-
proval by the Adminis'.raK-r. I'.*. Knviroriinei)!^
Protection Agency.
2. Frotfdurt
2.1 Selection of Measurr::v.<-nt ?:;*-. Piuupling or
velocity measurement is performed a; a site located at
least eight stack or duct diameters downstream and two
diameters upstream from any flow disturbance such as
a bend, eipansion, or contraction in the stack, or from a
visible flame. If necessary, an alternative location mav
be selected, at a position at least two stack or duct di-
ameters downstream and a ha!' diame:er upstream from
any flow disturbance. For a rectangular cross section.
an equivalent diameter (U.I shall be ca^iiiateu from the
following eqnation, to determine the upstream and
downstream distances:
D.=
ZLW
L-rW
FEDERAL REGISTER, VOL 42, NO. 160—THURSDAY, AUGUST It, 1977
-------
41756
RULES AND REGULATIONS
50
0.5
DUCT DIAMETERS UPSTREAM FROM FLOW DISTURBANCE (DISTANCE A)
1.0 1.5 2.0
2.5
I
I
40
o
a.
UJ '
V)
cc
UJ
^ .30
cc
u_
O
cc
UJ
§ 20
Z
s
D
S
Z 10
\
T
A
i
~L
B
i
—
—
I
k
'DISTURBANCE
MEASUREMENT
p- SITE
•
DISTURBANCE
* FROM POINT OF ANY TYPE OF
DISTURBANCE (BEND, EXPANSION. CONTRACTION. ETC.)
I
3 4 56 78 9
DUCT DIAMETERS DOWNSTREAM FROM FLOW DISTURBANCE (DISTANCE B)
Figure 1-1. Minimum number of traverse points for particulate traverses.
10
where £=leugtb and H'=widtb.
2 .2 Determining the Number of Traverse Points.
2.2.1 Particulate Traverses. When the eight- and
two-diameter criterion can lie met, the minimum number
of traverse points shall be: (1) twelve, for circular or
rectangular stacks with diameters (or equivalent di-
ameters) greater than 0.61 meter (24 in.); '(2) eight, for
circular stacks with diameters between 0.30 and 0.61
meter (12-24 in.); (3) nine, for rectangular stacks with
equivalent diameters between 0.30 and 0.61 meter (12-24
in.).
When the eight- and two-diameter criterion cannot be
met, the minimum number of traverse points is deter-
mined from Figure 1-1. Before referring to the figure,
however, determine the distances from the chosen meas-
urement site to the nearest upstream and downstream
disturbances, aud divide each distance by tho stack
diameter or equivalent diameter, to determine the
distance in terms of the number of duct diameters. Then,
determine from Figure 1-1 the minimum number of
traverse points that corresponds: (17 to the number of
duct diameters upstream: and (2) to the number of
diameters downstream. Select the higher of the two
minimum numbers of traverse points, or a greater value,
so that for circular stacks the number is a multiple of 4,
and for rectangular stacks, the number is one of those
shown in Table 1-1.
TABLE 1-1. CroM-xctfaiial layout far rfCtnnff'.ilur sliekt
.Ma-
trix
lay-
out
..... 3*3
..... 4i3
..... 4x4
\aatbtr oftrtutrtt pointt;
12.
16.
30..
as..
oxo
6l5
7l6
7i7
FEDERAL REGISTER, VOl. 47, NO. 160—THURSDAY. AUGUST 18, 1977
-------
50
40
5
o.
UJ
<
o.s
RULES AND REGULATIONS
DUCT DIAMETERS UPSTREAM FROM FLOW DISTURBANCE (DISTANCE A)
1.0 1.5 2.0
41757
2.5
O
tc
20
i 10
I
I
I
I
\
^ /DISTURBANCE
MEASUREMENT
•>-' SITE
DISTURBANCE
I
; 3 4 5 67 8 9 10
DUCT DIAMETERS DOWNSTREAM FROM FLOW DISTURBANCE (DISTANCE R)
Figure 1-2. Minimum number of traverse points for velocity (nonparticulate) traverses.
2.2.2 Velocity (Non-Particulate) Traverses. When
velocity or volumetric flow rate is to be determined (but
not paniculate matter), tbe same procedure as that for
paniculate traverses (Section 2.2.1) is followed, except
that Figure 1-2 may be used instead of Figure 1-1.
2.3 Cross-Sectional Layout and Location of Traverse
Points.
• 2.3.1 Circular Stacks. Locate the traverse points.on
two perpendicular diameters adcording to Table 1-2 and
the example shown in Figure 1-3. Any equation (for
examples, sec Citations 2 and 3 in tbe Bibliography) that
Rives tbe same values as those in Table. 1-2 may be used
in lieu of Table 1-2.
For paniculate traverses, one of the diameters must be
in a plane containing the greatest expected concentration
variation, e.g.. after bends, one diameter shall be in the
plane of the bend. This requirement becomes'less critical
as the disiancc from the disturbance increases; therefore,
other diani'Her locations may be used, subject to approval
Oi'tlie Administrator.
In addi:ion, for stacks having diameters greater than
0.61 m (24 in.) no traverse points shall be located within
2.5 centinu-iers (1.00 in.) of tbe stock walls; and for stack
diameters f-fjual to or less than 0.61 m (24 in.), no traverse .
point* shall be located will.in 1.3 cn> (0.50 in.) of the stack
walls. To u;eet these criteria, observe the procedures
given below.
2.3.1.1 Stacks With Diameters Greater Than 0.61 m
(21 in.). When any of the traverse poinrs as located in
Section Q.3.1 fall within 2.5 cm (l.OOin.) of the stack walls,
relocate th«*m away from the stack walls to: (I) a distance
of 2.5 cm (1.00 in.); or (2) a distance equal to the nozzle
inside diaxeter, whichever is larger. These relocated
traverse points (on each end of a diameter) shall be the
"adjusted'1 traverse points.
\\ heneviT two successive traverse points are combined
to form a single adjusted traverse point, treat the ad-
justed poi": as two separate traverse points, both in the
sampling kor velocity measurement) procedure, and in
FEDERAL REGISTER, VOL 42, NO. 160—THURSDAY, AUGUST 18, 1977
-------
41758
imES *3& BIGULAT10NS
TRAVERSE
POINT
1
2
4
S
6
Figure 1-3. Example showing circular stack cross section divided into
12 equal area*, with location of traverse points indicated.
'«)in stacta having tangmUil Inlets or other duet con-
flgrmitliTin wUeh tend to Indues swirling; In then
Instances, on pnauuco or absence of cyclonic flaw at
the sampling location must be determined. The following
tecbniqaea ore acceptable tor this determination.
I
0,0,0
1-—-J---
.0 J O J O
Figure 1-4. Example showing rectangular stack cross
section divided into 12 equal area* with a travane
point at centroid of each area.
'
Table 1-2. LOCATION OF TRAVERSE POINTS IN CIRCULAR STACKS
(Percent of stack diameter from inside wall to traverse point)
Traverse
point
number
on a •
diameter
1
2
3
«l
5'
6
7
8
9
10
11
«!
13
U
15
16
17
18
19
20:
. 21
22
23
24
Number of traverse points on a diameter
2
14.6
85.4
•
i
'
4
6.7
25.0
75.0
33.3
6
4.4
14.6
29.6
70.4
85.4
95.6
•
8
3.2
10.5
19.4
32.3
67.7
80.6
89.5
96.8
*
.
"
10
2.6
8.2
14.6
22.6
34.2
65.8
77.4
85.4
91.8
97.4
12
2.1
6.7
11.8
17.7
25.0
35.6
64.4
75.0
82.3
88.2
93.3
97.9
14
1.8
5.7
9.9
14.6
20.1
26.9
36.6
63.4
73.1
79.9
85.4
90.1
94,3
98.2
16
1.6
4.9
8.5
12.5
16.9
22.0
28.3
37.5
62.5
71.7
78.0
83.1
87.5
91.5
95'. 1
98.4
18
.1.4
4.4
7.5
10.9
14.6
18.8
23.6
29.6
38.2
61.8
70.4
76.4
81.2
85.4
89.1
92.5
95.6
98.6
20
1.3
3.9
•6.7
.9.7
12.9
16.5
20.4
25.0
30.6
38.8
61.2
69.4
75.0
79.6
83.5
87.1
90.3
93.3
96. 1
98.7
22
1.1
3.5
6.0
8.7
11.6
14.6
18.0
21.8
26.2
31.5
39.3
60.7
68.S
73.8
78.2
82.0
85.4
88.4
91.3
94.0
96.5
98.9
24
1.1
3.2
5.5
7.9
10.5
13.2
16.1
19.4
23.0
27.2
32.3
39.8
60.2
67.7
72'. 8 '
77.0
80.6
83.9
86.8
89.5
92*. 1
94.5
96.8
98.9
JJ.U Stacks With Diameters Equal to or Less Than
0.61 m (24 In.). Follow the procedure In Section 2J.1.1,
noting .only that any. "adjusted" points should be
relocated away from the stack walls to: (1) a distance of.
1.3 cm (0.50 in.); or (2) a distance equal to the noule
Inside diameter, whichever Is larger.
2.3.2 Rectangular Stacks. Determine the number
• of traverse points as explained In Sections 2.1 and 2.2 of
tnis method. Fronj Table 1-1, determine the grid con-
figuration. Divide the stack cross-section- Into as many
eo.ua! rectangular elemental areas as traverse points.
and then locate a traverse point, at the rentrold of each
equal ana according to the example In Figure 1-4.
The situation of tnverae points being too close to the
atack walls Is not expected to arise with rectangular
«fa**V" If this problem should ever arise, the Adminis-
. tntor must be contacted for resolution of the matter,
2.4 Verification of Absence of Cyclonic Plow. In most
stationary sources, the direction of stack gas flow is
essentially parallel to ibe stack walls. However,
cyclonic flow may exist (1) after such devices as cyclones
and inertial demisten following venturi scrubbers, or
Level and nto the manometer. Connect a Type 8
pilot tube to the manometer. Position the Type V^dtot
tube at each traverse point. In succession, so that the
planes of the face openings of the pi tot tnbe are perpendic-
ular to the stack cross-sectional pjanrwtum the Ttoe 8
pilot labels In this position. It Is at "0" reference.*'Note
the differential pressure (Ap) reading at each Inverse
point. U a null (zero) pilot reading Is obtained at 0*
reference at a given traverse point, an acceptable flow
condition exlttrat that fioint. If the pttot raiflliij {• not
«ero «tO* reference, rotate the flttot tone (op to ±90^ yaw
angle),an tHanuareadlnxIsobtalned. Caremlly'determine
and record the value of the rotation angle (a) to the
nearest degree. After the mill technique has been applied
at each travrse point, calculate the average of the abso-
lute values of
-------
RULK AND REOULATIONS
41759
10.2.54 em«
(0.75-1.0 in.)
* "jr*™"™* tiBS£S&f353£^3DP^
T , 7.62 cm (3 in.)'
TEMPERATURE SENSOR
LEAK-FREE
CONNECTIONS
•SUGGESTED (INTERFERENCE FREE)
PITOT TUBE • THERMOCOUPLE SPACING
Figure 2-1. Type S pilot tube manometer assembly.
2.1 Typ« S Pilot Tube. The Type 8 pilot tube
(Figure 2-1) shall be made of meta) tubing (e.g.. stain-
less sleel). It is recommended that the external lubing
diameter (dimension D,. Figure 2-2b) be between 0.48
and 0.95 centimeters (Me and H inch). There shall be
an equal distance from the base of each leg of the pilot
tube to its face-opening plane (dimensions PA and PB,
Figure 2-2H); It is recommended that this distance be
' between 1.05 and 1.50 times the external tubing diameter.
The face openings of the pilot tube shall, preferably, be
aligned as shown in Figure 2-2; however, alight misalign-
ments of the openings are permissible (see Figure 2-3).
The Type S pitot tube shall have a known coefficient,
determined as outlined in Section 4. An Identification
number shall be assigned to the pitot to be; this number
shall be permanently marked or engraved on the body
of the tube.
IEGISTH, VOL. 42, NO. 160—THU*SDAY, AUGUST 18. 1977
-------
ffTDO
JBttES *«& SEOUIAT1OHS
TRANSVERSE
TUBE AXIS
\
FACE
h*~ OPENING
PLANES
(a)
LONGITUDINAL
Dt
A SIDE PLANE
TUBE AXIS
8
NOTE:
PA-PB
B-SIDE PLANE
(b)
A ORB
(c)
Figure 2-2. Properly constructed Type S pitot tube, shown
in: (a) end view; face opening planes perpendicular to trans-
verse axis; (b) top view; face opening planes parallel to lon-
gitudinal axis; (c) side view; both legs of equal length and
center lines coincident, when viewed from both sides. Base-
line coefficient values of 0.84 may be assigned to pitot tubes
constructed this way.
KOERAi REGISTER, VOL 42, NO. 160—THURSDAY, AUGUST ) 8, 1977
-------
TRANSVERSE
TUBtAXB ,r
1UIES A>JD REGULATIONS
'-•'''''^•.^£^L ,".:,;.,.•- /.
fv |«i; \«2
r rf¥ V^l
b; / v;
• I'.'-'. t..-
41761
(f)
W
Figure 2-3. Types of face-opening misalignment that can result from field use or im-
proper construction of Type S pitot tubes. These will not affect the baseline value
of Ifpfe) so long as 01 and a2 < 10°. 01 and fa < 5°. z < 0.32 cm (1/8 in.) and w <
a08 cm (t/32 in.) (citation 11 in Section 6).
f&EML tECISTW, VOL 42, NO. 16O—THUMOAt. AUGUST 18, 1977
-------
41762
RtflH AfSO REGULATIONS
A standard pftct tab« mar be nsed Instead of a Type 8,
Provided that It n*ets the specifications of Sections 17
and 4.2; note, btwever, that th« static and Impact
pressure holes oT c&ndord pi tot tubes are susceptible to
plucking in part: rt late-laden gas streams. Therefore,
whenever a sia^-iArd pitot tube Is used to perform a
traverse. adequv.* proof must be furnished that the
openings of Ihe p:'->t tube hare not plugged up during the
traverse period: :i;' can be done by taking a Telocity
head (Ap) readin. • the final traverse point, cleaning oat
the impact and si* x holes of the standard pitot tube by
"bark-punting" ». i pressurized air, and then taking
another Ap readi- If the AD readings made before ana
after the air purr .t the same (tS percent), the traverse-
is acceptable. Oi.-Krwise, reject the run. Note- that ft Ap.
at the anal tro-.-rw point is unsuitably low, another
point may be stated. If *'back-purging" at regular
Intervals is pan cJ :he procedure, then comparative Ap
readings shall be uktn, as above, for the last two back
purges at which nimbly high Ap readings are observed.
2.2 Differential Pressure Gauge. An inclined manom-
eter or eqnivalpr.i device is used. Most sampling trains
are equipped wi:h a 10-in. (water column) inclined-
vertical manomelf?, having 0.61-in. HjO divisions on the
0- to 1-ln. Inclined scale, and 0.1-in. HiO divisions on the
1- to 10-in. vertical scale. Thia type of manometer (or
other gauge of equivalent sensitivity) Is satisfactory far
the measurement of Ap values as tow as 1.3 mm (0.06 In.)
HiO. However, a differential pressure gange of greater
sensitivity shall be toed (subject to the approval of the
Administrator), if any of tbe following Is, toond to be
true: (I) the arithmetic average of all Ap readings at the
traverse points in the stack is less than 1.3 mm (0.05 Uk)
HiO; (2) for trave»» of 12 or more points, more than 10
percent of the Individual Ap readings an below IS mm
(0.05 in.) BiO: (3; lor traverses of fewer than 12 points,
more than one Ap reading is below 1.3 mm (0.06 in.) HiO.
Citation 18 in Section 6 describes commercially available
instrumentation for the ineasnremen t of low-range gas
velocities.
As an alternative to criteria (1) through (3) above, the
following calculation may be performed to determine the
necessity of using a more sensitive differential pressure
gauge:
where:
Ap(=Individual velocity head reading at a traverse
point, mm BiO (in. H.O).
n=Total number of traverse points.
K=0.13 jnm U.-O when metric units are tued and
0.005 In HrO when English units are used.
If T is greater than 1.05, tbe velocity head data are
unacceptable and a more sensitive differential pressure
gauge must be used.
NOTE.—If differential pressure gauges other than
inclined manometer: are used (e.g., magncbelic gauges),
their calibration must be checked after each test series.
To check the calibration of a differential pressure gauge,
compare Ap readings of the gauge with those of a gauge-
oil manometer at i ninimum of three points, approxi-
mately representing ;iie range of Ap values in the stack.
If. at each point, the values of Ap as read by the differen-
tial pressure gauge and gauge-oil manometer agree to
within 5 percent. *:.? differential pressure gauge shall be
considered to be !.-. proper calibration. Otherwise, the
test scries shall pi::..?.- be voided, or procedures to adjust
the measured Ap vaiucs and final results shall be used.
subject to the a^provrJ of the Administrator.
2.3 Temperature Gauge. A thermocouple, liquid-
rilled bulb UienconM-ter, bimetallic thermometer, mer-
cury-in^lass thermometer, or other gauge capable of
measuring teir.pi-ra-.ure to within 1.5 percent of the mini-
mum absolute E;S.£ temperature shall be used. The
temperature gaufc s::all be ailttched to the pitot tube
such that the SPIGOT tip does not touch any metal; the
gauge shall be in a^ interference-free arrangement with
respect to the pitci lube fcce openings (see Figure 2-1
and also Figure 2-7 :n Section 4). Alternate positions may
bo used if the i'-;:.-: '.abe-Urr.pcrature gauge system ia
calibrated accord:^ to the procedure of Section 4. Pro-
vided that a difference of not more than 1 percent in the
average. velocity ^.easurcment is introduced, the tcm-
perature gangs need not be attached to the pitot tube;
this alternative ii subject to the approval of tbe
Administrate:-.
2.4 Pressure Probe and Gauge. A pleiometer tube and
mercury- or water-filled TJ-tube manometer capable of
measuring stack pressure to within 2.5 mm (0.1 in.) Hg
Is used. The static tap of a standard type pitot tube or
one leg of a Type X pitot tube with the face opening
planes positioned parallel to the gas flow may also be
used as the pressure probe.
2.5 Barometer. A mercury, aneroid, or other barom-
eter capable of measuring atmospheric pressure to
within 2.6 mm Hg (0.1 in. Hg) may be used. In many
cases, the barometric reading may be obtained from a
nearby national weather oervioe station, in which 'case
the station value (which Is the absolute barometric
pressure) shall be requested and an adjustment for
elevation differences between the weather station and
the sampling point shall be applied at a rate of minus
2.5 mm (0.1 In.) Eg per 30-meter (100 foot) elevation
Increase, or vice-versa for elevation decrease.
2.6 Gas Density Determination Equipment. Method
3 equipment, if needed (see Section 3.6), to determine
tbe stack gas dry molecular weight, and Deference
Method 4 or Method 5 equipment for moisture content
determination; other methods may be used subject to
approval of tbe Administrator.
2.7 Calibration Pitot Tuba. When calibration of tbe
Type S pitot tube to necessary (see Section 4), a standard
pitot tube Is and as a reference. The standard pitot
tube shall, preferably, have aknown coefficient, obtained
either 0) directly from the National Bureau of Stand-
ards, Boute 270, Quince Orchard Road, Galthersburg,
Maryland, or (2) by calibration against another standard
pttot'*jbe with' an NBS-traoeable coefficient. Alter-
natively, a standard pitot tube designed according to
the criteria given In 2.7.1 through 2.7.5 below and Illus-
trated In Figure 2-4 (see also Citations 7, 8, and 17 In
Section 6) may be used. Pitot tubes designed according
to these specifications will have baseline coefficients of
about 0.09±0.01.
2.7.1 HemtspherIcaUshownlnFlgure2-4).elllpsoIdal.
or conical tip.
2.7 J A minimum of six diameters straight run (based
upon D, tbe external diameter of the tube) between the
Up and tbe static pressure holes. .-'
2.7.3 A minimum of eight diameters straight run1
between the static pressure holes and the centerline of
tbe external tube, following tbe 90 degree bend.
2.7.4 Staliepressure.holesofequalslze (approximately
0.1 D), equally spaced In a piezometer ring configuration.
2.7.5 Ninety degree bend, with curved or mltered
junction.
2.8 Differential Pressure Gauge for Type S Pilot
Tube Calibration. An inclined manometer or equivalent
Is used. If the single-velocity calibration technique Is
employed (see Section 4.1.&3), the calibration differen-
tial pressure gauge shall be readable to tbe nearest 0.13
mm HiO WMtin. JIiO). FormulUveloctty calibrations,
the gauge shall be readable to tbe nearest 0.13 mm HrO
(0.005 In HiO) for Ap values between 1.3 and 25 nun HtO
(0.05 and 1.0 In. BiO), and to the nearest L3 mm HiO
(0.05 in. H*0) for Ap values above S mm HjO (1.0 in.
*">>. A tstOA more «em«rn cram wlD be required
to read""AT°varaM'belowT.» mm
(see Citation 18 In Section t).
I (0.05 In. HiO]
CURVED OR
MITERED JUNCTION
STATIC
HOLES
(-0.1DJ
. HEMISPHERICAL
T"
Figure 2-4. • Standard pitot tube design specifications.
3. Procedure
3.1 Set op the apparatus as shown in Figure 2-1.
Capillary tubing or surge tanks installed between the
manometer and pitot tube may be used to dampen Ap
fluctuations. It is recommended, but not required, that
a pretest leak-check be conducted, as follows: (1) blow
through the pitot impact opening until at least 7.6 cm
(3 in.) IliO velocity pressure registers on tbe manometer;
then, close off the impact opening. The pressure shall
remain stable for at least 15 seconds; (2) do the same for
the static pressure side, eicept using suction to obtain
the minimum of 7.6 cm (3 in.) HtO. Other leak-check
procedures, subject to the approval of the Administrator,
may be used. -
3.2 Level and zero the manometer. Because the ma
nometer level and zero may drift due to vibrations and
temperature changes, make periodic checks during the
traverse. Record an necessary data as shown in the
example data sheet (Figure 2-5).
3.3 Measure the velocity head and temperature at the
traverse points specified by Method 1.- Ensure that the
proper differential pressure gauge is being used (or the
range of Ap values encountered (see Section 2.2). If it la
necessary to change to a more sensitive gauge, do so, and
remeasnre tbe Ap and temperature readings at each tra-
verse point. Conduct a post-test leak-check (mandatory),
as described in Section 3.1 above, to validate We traverse
run.
3.4 Measure the static pressure In the stack. One
reading is usually adequate.
3.5 Determine the atmospheric pressure.
FEDEBA1 REGISTER. VOL 41, NO. 160—THURSDAY, AUGUST 18, 1977
-------
RULES AND REGULATIONS
41763
MAPfT .
pftTP RUM an
STACK DIAME
BAROMETRIC
CROSS SECTIO
OPERATORS _
WTOTTUBtU
AVG.COEF
LAST DATE
Travcnt
Ptllo.
-
-
TER OR DIMENSION*
PRESSURE, mm Kg (i
BAt ARFA m2(ftZ)
? m(ttt) , _^
" "af
n-im
pIMPMT p. • as .
fAIIRRATFn
VtI.Hl.Aj.
mnrftUHzO
Cfa* k T«niM*r«inm
%,°cm
^
-
Avtnp
Tfc»K{«W
,
-.
SCHEMATIC OF STACK
CROSS SECTION
wnHft'tuUti)
•
'
-
•
.«•
Figure 2-5. Velocity traverse data
, VOL 42, NO. 1«0—TKUtSDAY, -AUGUST II. 1477
-------
41764
RUUS AND REGULATIONS
».« Determine «n» stack 31* flry motoauar jwfcbt.
For oombtKtitm tncean* or procesaoa that emit eoan-
tlaDy CO*. Ofc CO, and Ni. oao Method a. For processes
omitting resentfully air, an analysis need not be con-
ducted; use • dry auleealar weight of 29.0. For other
processes, other methods, subject to the approval of the
Administrator, xunst be used.
3.7 Obtain U» nioistnra content bom Reference
Method 4 (or equivalent) or from Method ft.
3.8 Determine the aosMectlonalarea of the stock
or duct at the tr ojpHng location. Whenever possible,
physically mease . the stack dimensions rather than
•using Uuenrloav
4.1 Type 8 Pftot Tub*. Baton its Initial use, care-
fully examina the Type 8 pitot tube hi top, ride, and
end vtows to verify that the face openings of the tube
are aligned within the specifications illustrated In Figure
2-S orMTTbe pttot tube abaB not be and If it bib to
meet these alignment spedflcsttons.
After verifying the taoe opening alignment, measure
and record thefBQowing dimensions of the pilot tube:
AO the eitams! tnbuu dtametar (dimension D,, Figure
z-zb); and (b) the Dose-to-opanlnf plane distances
(dunenstaB PA and P*. Figure iMo). lfx>, b between
0.48 and 0.91 «m (Mt and H tn.) and If J>4 and PC an
equal and between 1.05 and 1.50 KI, there are two possible
options: (I> the pttot tube may be calibrated according
to the procedure outlined In Sections 4.1.2 through
4.14 below, or (2) • baseline (Isolated tube) coefficient
value of 0.84 may be assigned to the pltot tube. Note,
however, that if the pltot tube is part of an assembly,
calibration may still be required, despite knowledge
of the baseline coefficient value (see Section 4.1.1).
If D,, Pf.faAPatat outside the specified limits, the
pitst tube mast be calibrated as outlined in 4.1.2 through
4.1J below.
4.1.1 Type 8 Pttot Tube Assemblies. During sample
and Telocity traverses, the isolated Type 8 pltot tube is
not always oaed: In many Instances, the pilot tube is
used In combination with other source-sampling compon-
ents (thermocouple, sampling probe, noiile) as part of
an "assembly." The presence of other sampling compo-
nents can sometimes affect the baseline value of the Type
8 pilot tube coefficient (Citation 8 In Section 6); therefore
an assigned (or otherwise known) baseline coefficient.
TYPE SPtTOT TUBE
vatae may or may not be rand for • given assembly. The
baseline and assembly coefficient value* will be Identical
only -when the relative placement of the components In
the assembly b such that aerodynamie Interference
effects are eliminated. Figures 2-6 through 2-8 Illustrate
Interference-free component arrangements for Type 8
pltot tubes having external tubing diameters between
0.48 and 0.85 cm (Mi and H In.). Type 8 pltot tube assem-
blies that fad to meet any or all of the specifications of
Figures 2-6 through 2-6 snail be calibrated according to
the procedure outlined In Sections 4.1.2 through 4.1.8
below, and prior to calibration, the values of the Inter-
component spaolngs (pltot-nonle, pilot-thermocouple,
pilot-probe sheath) ahan be measured and recorded.
Norm.—Do not its* any Type 8 pilot tube assembly
which is constructed such that the Impact pressure open-
ing plane of the pltot tube b below the entry plane ofthe
notie (see Figure S-6b). :
4.1.2 Calibration Setup. If the Type 8 pltol tube is lo
be calibrated, one leg of the tube shall be permanently
marked A, and the other, 3. Calibration shall be done in
a flow system having the following essential design
features:
I
i
r£ IJ3 OR (1/4 M FOR 0, -'1.3 cm {1/2 faj
SAMPLIWGHOZZLE
A. BOTTOM VIEW; SHOWING MINIMUM PITOT-NOZZLE SEPARATION.
SAMPLING
PROBE
SAMPLING
NOZZLE
STATIC PRESSURE
OPENING PLANE
IMPACT PRESSURE
OPENING PLANE
B. SIDE VIEW; TO PREVENT PITOT TUBE
FROM INTERFERING WITH GAS FLOW
STREAMLINES APPROACHING THE
NOZZLE. THE IMPACT PRESSURE
OPENING PLANE OF THE PITOT TUBE
SHALL BE EVEN WITH OR ABOVE THE
NOZZLE ENTRY PLANE.
Figure 2-6. Proper pitot tube • sampling nozzle configuration to prevent
aerodynamic interference; buttonhook • type nozzle; centers of nozzle
and pitot opening aligned; Dt between 0.48 and 0.95 cm (3/16 and
3/8 in.). .
FEDERAL REGISTER, VOL 42, NO. 160—THURSDAY, AUGUST 18, 1977
-------
8UIES
41765
mmUICOUPU
TYrtSPITOTTUBE
SAMPLE PROBE
Figure 2-7. Proper thermocouple placement to prevent interference;
Dt between 0.48 and 0.95 cm (3/16 and 3/8 in.). -
TYPE SPITOT TUBE
Y>7.62cm(3inJ
n;yi HI
SAMPLE PROBE
Figure 2-8. Minimum pitot-sample probe separation needed to prevent.injterference;
Dt between 0.48 and 0.95 cm (3/16 and 3/8 in.).
4.1.2.1 The flowing f«3 stream must be confined to •
duet a! definite croci nnniniml an*, tuber circular or
netauKola?. For eimdur eross-aectlana, the minimum.
duet diameter shall be 30.5 em (13 In.); for rectangular
riws-eocUoni, the width febortor side) shall b« at least
25.4 cm (10 in.).
4.1.2 J The eross-Geettonal area of the calibration duct
most be constant over a distance of 10 or more duet
dianuters. For a "ytft"g"T"' cross-section, use an equiva-
lent diameter, calculated from the following equation,
to determine the number of duct diameters:
/>.=
2LTV
(L+W)
Equation 2-1
where:
.».=Equivalent diameter
i= Length
»'=Widtb
To ensure the presence of stable, fully developed flow
patterns at the calibration site, or "test section," the
site must be located at least eight diameters downstream
and two diameters upstream from the nearest disturb-
ances.
NOTE.—The eight- and two-diameter criteria are not
absolute; other test section locations may be used (sub-
ject to approval of the Administrator), provided that the
flow at the test site Is stable and demoustrably parallel
to the duct ails.
4.1.2.3 Tbe flow system shall have the capacity to
generate a test-section velocity around 915 m/min (3,000
ft/min). This velocity must be constant with time to
guarantee steady flow during calibration. Note that
Type 8 pitot tube coefficients obtained by single-velocity
calibration at 915 m/min (3,000 ft/min) will generally be
valid to within ±3 percent for the measurement of
velocities above 305 m/min (1,000 ft/mln) and to within
±6 to 6 percent for the measurement of velocities be-
tween 180 and 305 m/mtn (MO and 1,000 ft/min). If a
more precise correlation between C, and velocity is
desired, the flow system shall have the capacity to
generate at least four distinct, time-invariant test-section
velocities covering the .velocity range from 180 to 1,525
m/min (600 to 5,000 ft/mln), and calibration data shall
be taken at regular velocity Intervals ever this range
(see Citations 9 and 14 in Section < for details).
4.1.2.4 Two entry ports, one each for the standard
and Type S pilot tubes, shall be, cnt in the test section;
the standard pitot entry port shall be located slightly
downstream of the Type B port, so that the standard
and Type S impact openings will lie in the same crass-
sectional plane during calibration. To facilitate align-
ment of the pitot tubes during calibration, it is advisable
that the test section be constructed of pleiiglas or some
other transparent material.
4.1.3 Calibration Procedure. Note that this procedure
Is a general one and must not be used without first
referring to the special considerations presented in Sec-
tion 4.1.5. Note also that this procedure applies only to
single-velocity calibration. To obtain calibration' data
for the A and B sides of the Type S pitot tube, proceed
as follows:
4.1.3.1 Make sure that the manometer is properly
filled and that the oil is free from contamination and is of
the proper density. Inspect and leak-check all pitot lines;
repair or replace if necessary.'
4.1.3.2 Level and tero the manometer. Turn on Hie
fan and allow toe flow to stabilise. Seal tbe Type S entry
port. • - ' — -
4.1.SJ Ensure that the manometer is level and leroed.
Position the standard pitot tube at the calibration point
(determined as outlined in Sction 4.U.I), and align the
tube so that its tip is pointed directly into the flow. Par-
ticular care should be taken in aligning the tube to avoid
yaw and pitch'angles. Make sure that the entry port
surrounding the tube is properly sealed. .'
4.1.3.4 Read Ap.td and record,its value in a'data table
similar to tbe one shown in 'Figure 2-9. Remove the
standard pitot tube from the duct and disconnect it from
the manometer. &eal the standard entry port.
4.1.3.5 .Connect the Type S pilot tube to the manom-
eter. Open the Typo S entry port. Check the manom-
eter level and tero. insert and align the Type S pitot tube
so that its A side impact opening is ax the same point as
was the standard pitot tube and is pointed directly into
tbe tlow. Make sure that the entry put surrounding the
tube is properly sealed.
4.1.3:6 Read Ap, and enter its value in the data table.
Remove the Type 8 pitot tube from the duct and dis-
connect it from the manometer.
4.1.3.7 Repeal steps 4.1.3.3 through 4.1.3.6 above until
three pairs of Ap readings have beer, obtained.
4.1.3.8 Repeat steps 4.1.3.3 through 4.1.3.7 above for
the B side of the Type S pitot tube.
4.1.3.9 Perform calculations, as described in Section
4.1.4 below.
4.1.4 Calculations.
4.1.4.1 For each of the sii pairs of ap readings (i.e.;
three from side A and three from side B) obtained in
Section 4.1.3 above, calculate the value of tbe Type S
pitoi ml* t'x-flicimt as follows:
F&KIAL REGISTEI, VOL 42, NO. 160—THUtSDAY, AUGUST J«, 1977
-------
41766
RUIES AND REGULATIONS
PirOTTUBE IDENTIFICATION NUMBER:
CALIBRATED BY?
.DATE:.
RUN NO.
1
2
3
"A" SIDE CALIBRATION
' APstrf
crnHjO '
(in. HjO)
Ap(j)
cmH20
(in.HaO)
CpfilDEA)
CpW
DEVIATION
CpM-CpjA)
,
RUN HO-.
1
i
3
"B" SIDE CALIBRATION
Apjtd
craHjO
(In. HzO)
- .-" " - ' '
APW
ernHjO
(in.HzO)
Cp(SIDEB)
CpW
' DEVIATION
CpM-CpW
•
AVERAGE DEVIATION = cr(AORB)
S|Cp(i)-Cp{AORB}|
-foUSTBE<0.01
| Cp (SIDE AJ-Cp (SIDE B) J-*-MU$T BE<0.01
Figure 2-9. Pitot tube calibration data.
Calculate the deviation of each of the three A-
dde-rahMaof C,(.) from (?, WdeA), and the deviation of
each B-elde value of C,M from C, (side B). Use the fol-
lowing equation:
Deviation=C,(.) — f?p(A of B) •
Equation 2-3
4.1.4.4 Calculate », the average .deviation from the
mean, for both the A and B sides of the pilot tube. Use
the following equation:
3
a (side A or B) =
•here:
Equation 2-2
'Type 8 pilot tube coefficient
=Standard pitot tube coefficient: use 0.99 if the
coefficient is unknown and the tube Is designed values.
according to the criteria of Sections 2.7.1 to
.2.7.5 of this method.
-Velocity bead measured by the standard pilot
tube, em HiO On. H|O)
Aj>.=Velocity bead measured by the Type 8 pilot
tube, em HjO On. HiO)
4J.4J Calculate C, (side AX the mean A-slde coef-
Equation 2-4
4.1.4.5 Use the Type S pitot tube only If the values of
• (side A) and * (side B) are less than or equal to 0.01
and If the absolute value of the difference between C,
(A) and C, (B) Is 0.01 or less.
4.1.4 Special considerations.
4.1.4.1 SelooUon of calibration point
4.1.S.1.1 When an Isolated Type 8 pitot tube Is cali-
brated, select a calibration point at or near the center of
the duct, and follow the procedures outlined In Sections
4.1.3 and 4.1.4 above. The Type S pitot coefficients so
obtained, Le., , (side A) and C, (side B), win be valid,
so long as either: (1) the Isolated pitot tube Is used; or
(2) the pitot tube Is used with other components (nozzle,
thermocouple, sample probe) in an arrangement that is
free from aerodynamic Interference effects (see Figure*
2-6 through 2-8).
4.1.4.1.2 For Type S pitot tube-thermocouple com-
bination* (without sample probe), select a caUbraUon
point at or near the center of the duct, and follow the
procedures outlined hi Sections 4.1.3 and 4.1.4 above.
The coefficients so obtained will be valid so long as the
pilot tube-thermocouple combination Is used by itself
or with other components in an interference-free arrange*
ment (Figures 2-6 and 2-8).
4.1.5.1.3 For. assemblies with sample probes, the
calibration point should be located at or near the center
of the duct; however. Insertion of a probe sheath Into a
small duct may cause significant cross-sectional area
blockage and yield incorrect coefficient values (Citation 9
in Section 6). Therefore, to minimize the blockage effect.
the calibration point may be a few Inches off-center If
necessary. The actual blockage effect will be negligible
when the theoretical blockage, as determined by a
projected-area model of the probe sheath, is 2 percent or
loss of the duct cross^ectional area for assemblies without
external sheaths (Figure 2-10a), and 3 percent or less for
•assemblies with external sheaths (Figure 2-10b).
4.1.5.2 For those probe assemblies In which pilot
tube-nozzle Interference is a {actor (i.e., those in which
the pltot-nozzel separation distance falls to meet the
specification Illustrated in Figure 2-6a), the value of
C,(.) depends upon the amount of free-space between
the tube and noitle, and therefore is a function of noule
size. In these instances, separate calibrations shall be
performed with each of the commonly used nozzle sizes
in place. Note that the single-velocity calibration tech-
nique is acceptable for this purpose, even though the
larger nozzlejsizes O0.635 cm or l/i In.) are not ordinarily
used for isokinetio sampling at velocities around 915
m/min (3,000 ft/mln), which is the calibration velocity;
note also that It Is not necessary to draw an Isokinetio
sample during calibration (see Citation 19 in Section 6).
4.1.5.3 For a probe assembly constructed such that
HJ pilot tube Is always used in the same orientation, only
one side of the pitot tube need be calibrated (the side
which will lace the'flow). The pitot tube must still meet
I be alignment specifications of Figure 2-2 or 2-3, however,
- and must have an average deviation (
-------
BOIES AND REGULATIONS
41767
ESTIMATED
SHEATH
BLOCKAGE
F lxw 1
[pUCTAREAJ
(b)
x 100
Figure 2-10. Projected-area models for typical pltot tube assemblies.
4.1.9 Field Use and Recalibratton. . . .
4.1.8.1 Field Dse. "
4.1.6.1.1 When m Type 8 pltot tube (Isolated tube or
assembly) la used In the field, the appropriate coefficient
Talue (whether assigned or obtained by calibration) shall
be used to perform velocity calculations. For calibrated
Type 8 pilot tabes, the A side coefficient shall be used
when the A side of the tube faces the flow, and the B side
coefficient shall be used when the B side faces tbe flow;
alternatively, tbe arithmetic average of the A and B side
coefficient values may be used, irrespective of which side
faces tbe flow. •
4 1.6.1.2 When a probe assembly is used to sample a
small duct (12 to 38 In. in diameter), tbe probe sheath
sometimes blocks a significant part of the duct cross-
section, causing*a reduction in the effective value of
,c.i • Consult Citation 9 In'Section 6 for details. Con-
ventional pilot-sampling probe assemblies are not
recommended for use in ducts having Inside diameters
smaller than 12 inches (Citation 16 in Section 6).
4.1.6.2 Becalibration.
4.1.62.1 Isolated Pltot Tubes. After each field use, the
pltot tube shall be carefully recxamined in top, side, and
end views. If the pilot face openings are still aligned
within the specifications illustrated in Figure 2-2 or 2-3,
It can be assumed that tbe baseline coefficient of the pltot
tube has not changed. If, however, the tube has been
damaged to tbe extent that it no longer meets Ibe specifi-
cations of Figure 2-2 or 2-3 the damage shall either be
repaired to restore proper alignment of the face openings
or the tube shall be discarded.
4.1.6.2.2 Pilot Tube Assemblies. After each field use,
check the face opening alignment of tlie pilot tube, as
In Section 4.1.6.2.1; also, remeasure tbe intercomponent
spacings of the assembly. If the intercom pouent spacinps
have not changed and the face opening alignment is
acceptable, It can be assumed that the coefficient of tbe
assembly has not changed. If the face opening alignment
is no longer within the specifications of Figure? 2-2 or
2-3, either repair the damage or replace the pilot tube
(calibrating the new assembly, if necessary). If tbe inler-
oomponcnt spacings have changed, restore the original
epacings or recalibrate tbe assembly.
4.2 Standard pilot tube (if applicable). If a standard
pltot tube Is used lor tbe velocity traverse, the tube shall
be constructed according to tbe criteria of Section 2.7 and
shall be assigned a baseline coefficient value of 0.99. If
the standard pilot tube is used as pan of an assembly.
the tabe shall be in an interference-free arrangement
(subject to the approval of the Administrator), •
4.3 Temperature Gauges. Alter each field use, cali-
brate dial thermometers; liquid-filled bulb thermom-
eters, thermocouple-potentiometer systems, and other
gauges at a temperature within 10 percent of the average
absolute stack temperature. For temperatures up to
405° C (761° F), use an ASTM mercury-in-glass reference
thermometer, or equivalent, as a reference; alternatively,
either a reference thermocouple and potentiometer
(calibrated by NBS) or Ibennomelric filed points, e.g.,
ice bath and boiling water (corrected for barometric
pressure) may be used. For lemperalnres above 405° C
(761° F), use an NBS-callbrated reference thermocouple-'
potenliometer system or an alternate reference, subject
to the approval of the Administrator.
If, during calibration, the absolute temperatures meas-
ured with the gauge being calibrated and Ibe reference
gauge agree wilhin 1J> percent, the temperature data
taken in the field shall be considered valid. Otherwise,
the pollutant emission tesl shall either be considered
invalid or ad]ustmenls (if appropriate) of the test results
shall be. made, subject to tbe approval of the Administra-
tor.
4.4 Barometer. Calibrate tbe barometer used against
a mercury barometer.
5. Calculation!
Carry out calculations, retaining at least ono extra
decimal figure beyond lhal of Ihe acquired data. Round
oil figures after llnal calculation.
5.1 Nomenclature.
X=Cross-sectional area of stack, m'(fl'). .
B«,=Water vapor in the gas stream (from Method 5 or
Reference Method 4), proportion by volume.
Cp=Pitol rube coefficient, dimensionless.
A',=Pilot tube constant,
?A 07 m r(g/g-mole)(minHg)'
J4-97^L c
for the inelric system and
°K)(mmHjOj J
for tbe English system.
Af j=Molecular weight of slack gas, dry basis (set
Section 3.6) g/g-mole (Ib/lb-mole)
. . if,—Molecular weight of stack gas, wet basil, g/g-
mole (Ib/lb-mole).
**Afrf (1—BM)-f-18.0 Bwt Equation 2-5
Pb,i=Barometric pressure al measurement site, mm •
Hg (in. Hg). . .' •
P,=fitack static pressure, mm Hg (In. Hg).
P,*=Absolute slack, gas pressure, mm Hg (in. Hg);
. . =.Pb.r+Pi . •• • Equation 2-fl
PI«=Standard absolute pressure, "60 mm Hg (29.92
in. Hg).
Q,i=Drv volumelric slack gas Eow rate corrected to
standard conditions, dscm/hr (dscf/br).
(,=Stack lemperalurc', °C (°F).
T.=Absolule stack temperature, °K (°R).
Equation 1-7
Equation 2-8
f. for metric
=400+1. for English
Taj=S!andard absolute temperature, 293 °K- (528* R)
F,=Average stack gas velocity, m sec (ft 'sec;.
Ap=V«locity head of slack gas, mm UiO (in. HiO):
3,600= Conversion factor, sec/hr.
18.0=Mo!ecular weight of water, g.'g-mo'.e flb-lb-
mole'1.
5.2 Avorsgc slack gas velocity.
5.3 Avi-:\i£0 tic
Equation 2-9
i (j;"L5 dry volumeiric flow rate.
ft r(lb/lb-mole)(in.Hg)-|'/'
sccL (°l{)(in. H,6) J
Equation 2-10
1. Mark. L. S. Mechanical Encineers' Handbook. Now
Yorkj McGraw-Hill Book Co., Inc. 1»M.
2. Perry. J. H. Chemical Engineers' Handbook. New
York. ilc
-------
47768
KU£S AND BE&UUUIONS
3. Solgehara, R. T., W. F. Todd, and W. 8. Smith.
Significance of Errors In Stack Sampling Measurements.
U.S. Environmental Protection Agency. Research
Triangle Park, N.C. (Presented at the Annual Meeting o(
the Air Pollution Control Association, St. Louis, Mo.,
June 14-19,19m)
4. Standard Method tor Sampling Stacks (or Farttcnlate
Matter. In: 1971 Book of ABTM Standards. Part 23.
Philadelphia, Pa. 1871. A8TM DesignatiorTD-2928-71.
S. Vennard, J. K. Elementary Fluid Morfinni.-^ New
York. John Wiley and Sow, Inc. 1947.
6. Fluid Meiers—Their Theory and Application.
American Society of Mechanical Engineers, New York,
7. ASURAE Handbook of Fundamentals. 1972. p. 208.
8. Annual Book of ABTM Standards, Part 26.1974, p.
648.
9. Vollaro, K. F. Guidelines for Type 3 Pilot Tube
Calibration. D.8. Environmental Protection Agency.
Research Tiangle Park, N.C. (Presented at 1st Annual
Meeting, Source Evaluation Society, Dayton, Ohio,
September 18.1375.)
10. Volhm. R. F. A Type 8 Pilot Tub* Calibration
Study. U.S. Environmental Protection Agency, Emis-
sion Measurement Branch, Research Tctangle Park,
N.C. July 1371.
11. Vollaro, B. f. The Eflects of Impact Opening
Misalignment on the Varna of the Type 8 Pilot Tube
Coefficient. U.8. Environmental Troteethro Agency,
Emission Measurement Branch fiesearch Triangle'
Park, N.C. October 1978.
12. Vollaro, R. f. Establishment of a Baseline Coeffi-
cient Value for Properly Constructed Type 8 Pilot
Tubes. U.S. Environmental Protection Agency, Emis-
sion Measurement Branch, Research Triangle Park,
N.C. November 1976.
13. Vollaro, R. T. An Evaluation of Single-Velocity
Calibration Techniques as a Means of Determining Type
S Pilot Tube Coefficients. U.S. Environmental Protec-
tion Agency, Emission Measurement Branch. Research
Triangle Park, N.C. August 1975.
14. Vollaro, B, F. The Use of Type 8 Pilot Tabes for
the Measurement of Low Velocities. U.S. Environmental
Protection Agency Emission Measurement Branch,
Research Triangle Park, N.C. November 1970. ,
15. Smith. .Marvin L. Velocity Calibration of EPA
Type Source Sampling Probe. United Technologies
Corporation, Pratt and Whitney Aircraft Division,
East Hartford. Conn. UTS.
16. Vollaro, R. F. Recommended ProeednmJbr Simple
Traverses in DncU Smaller than 12 laches In I>iatnet4r.
U.S. Environmental Protection Agency, Emission
Measurement Branch, Research Triangle Park, N.C.
November 1976.
17. Over, E. and R. C. Pankhnrst. The Measurement
of Air Flow, 4th Ed. London, Pergamon Press. 1968.
18. Vollaro, B. F. A survey of Commercially Available
Instrumentation for the Measurement of low-Bang)
Gas Velocities. U.S. Environmental Protection Agency,
Emission Measurement Branch, Research Triangle-
Park, N.C. November 1976. (Unpublished Paper)
19. dnyp. A. W, C. C. St. Pierre. D. & Smith, D.
ilazzon, and J. Steiner. An Experimental Investigation
of the Effect of Pilot Tube-Sampling Probe Configura-
tions on the Magnitude of the 8 Type Piutt Tube Co-
efficient for Commercially Available Source BamnUng
Probes. Prepared by the Tfolmrslty of Windsor tor th»
Ministry of the Environment,' Toronto, Canada. Feb-
ruary 1975.'
METHOD 3—OAS ANALYSIS rom CABBON DIOXIDE,
OXYOEN, EXCESS AIR, AND DBT MOLECULAB WEIGHT
1. Principle and ApfOalMtUf
1.1 Principle. A gas sample Is extracted from a alack,
by one of the following methods: (1) single-point, grab
sampling; (2) single-point, Integrated sampling; or (S)
multi-print, Integrated sampling. The gas sample li
analysed for percent carbon dloxwe (CO>), percent oxy-
gen (O>). and, U necessary, percent carbon monoidae
(CO). U a dry molecular weight determination is to be
made, either an Orsat or a i'yrile • analyzer may be used
for the analysis: for excess air or emission rate correction
factor determination, an Orsat analyzer must be used.
1.2 Applicability. This method is applicable for de-
termining COi and Oj concentrations, excess air, an'd
dry molecular weight of a sample from a gas stream of a
fossil-fuel combustion process. The method may also he
applicable toother processes whereith»been determined
that compounds other than COi, Oi, CO, and nitrogen
-------
RULES AND REGULATIONS
41769
PROBE
FILTER (GLASS WOOL)
TO ANALYZER
SQUEEZE BULB
Figure 3-1. Grab-sampling train.
RATE METER
PROBE
AIR-COOLED
CONDENSER
FILTER
(GLASS WOOL)
RIGID CONTAINER
Figure 3-2. Integrated gas-sampling train.
fOERAL REGISTH, VOL 42, NO. 160—THURSDAY, .AUGUST It. 1977
-------
41770
SUtB AND REGULATIONS
2,2.2 Condenser. An air-cooled or water-cooled eon-
denser, or other condenser that win not remove O*
COt, CO, and Xt, may be used to remove excess mnbtnre
which would Interfere with tbe operation of tbe pomp
and flow .meter.
2.2.8 Valve. A needle valve Is used to adjust sample
gas flow rate.
2.2.4 Pnmp. A leak-free, diaphragm-type pomp, or
equivalent. Is csed to transport sample gas to the fl»**Trii»
bag. Install a ratal! surge tank between tbe pomp mnd
rate meter to eliminate the pulsation effect of tbe dia-
phragm pumr on the rotameter.
2.2.8 Jut, Meter. Tbe rotameter, or equivalent rat*
meter, used jonld be capable of measuring flow nta
to within dt-> percent of the selected flow rate. A flow
rate range of 500 to 1000 cm'/mln is suggested.
2.2.6 Flexible Ban. Any leak-free plastic (e.g., Tedlar.
Mylar, Teflon) or plastic-coated aluminum (e.g., alumi-
nized Mylar) beg, or equivalent, having a capacity
consistent with the selected flow rate and time length
of tbe test ran. may be used. A capacity in the range of
65 to 90 liters is snggested.
To leak-check tbe bag, connect It to a water manometer
and pressurize tbe bag to S to 10 cm HiO (2 to 4 In. HiO).
Allow to stand lor 10 minutes. Any displacement In the
water manometer Indicates a leak. An alternative leak-
check method is to pressurize the bag to £ to 10 cm HiO
(2 to 4 In. HiO) and allow to stand overnight. A deflated
bag Indicates a leak.
2.2.7 Pressure Gauge. A water-filled U-tnbe manom-
eter, or equivalent, of about 28 cm (12 in.) is used for
tbe flexible bag leak-check.
223 Vacuum Gauge. A mercury manometer, or
equivalent, of at least 760 mm Hg (30 in. Hg) to used tor
the sampling train leak-check.
2.3 Analysis. For Orsat and Fyrlte analyzer main-
tenance and operation procedures, follow tbe instructions'
recommended by tbe manufacturer, muecs otherwise
specified herein.
2.3.1 Dry Molecular Weight Determmstkm. An Omt
analyzer or Fyrite type combustion gas analyzer may be
2.3.2 Emission Rate Correction Factor or Excess Air
Determination. An Orsat analyzer must be used. For
low COi (less tban 4.0 percent) or high Ot (greater than
15.0 percent) concentrations, tbe measmtng tjurette of
tbe Orsat must have at least OJ percent subdivisions.
3. Dn Moltcalar BVfJM Dttcrmtnatim
Any of the three sampling and analytical procedures
described below may be used tor determining tbe dry
molecular weight.
3.1 Single-Point, Grab Sampling end Analytical
. Procedure.
3.1.1 The sampling point In the duct shall either be
at the eentroid of the cross section or at a point no closer
to the walls than 1.00m (3.3 ft), unless otherwise specified
by tbe Administrator.
3.1.2 Set up tbe equipment as shown in Ftetm 8-1,
making sure all connections ahead of the analyzer are .
tight and leak-free. II an Orsat analyzer is used, it is
recommended that tbe analyzer be leaked-checked by
following the procedure in Section 5; however, tb* leak-
check Is optional.
3.1.3 Place tbe probe in the stack, with tbe tip of tb*
probe positioned at tbe sampling point; purge the sampl-
ing line. Draw a sample into the analyzer and imme-
diately analyze it for percent COiand percent Ot. Deter-
mine the percentage of the gas that is Nt and CO by
subtracting tbe sum of tbe percent COt and percent Ot
from 100 percen:. Calculate the dry molecular weight as
• Indicated In Section 6.3.
3.1.4 Repeat the sampling, analysis, and calculation
procedures, until the dry molecular weights of any three
grab samples differ from tbelr mean by no more tban
0.3 g/g-mole (OJ Ib/lb-mole). Average these three molec-
ular weights, and report tbe results to the nearest
0.1 g/g-mole (lb,1b-mole).
3.2 Single-Point, Integrated Sampling and Analytical
Procedure.
3.2.1 Tbe sampling point In tbe duct shall be located
as specified in Section 3.1.1.
3.2.2 Leak-check (optional) the flexible bag as In
Section 2.2.6. Set up the equipment as shown in Figure
3-2. Just prior to sampling, teak-check (optional) tbe
train by placing a vacuum gauge at the condenser inlat,
pulling a vacuum of at least 250 ™™ Hg (10 in. Hg),
plugging the ouUet at the quick disconnect, and then
turning off the pump. The vacuum should-remain stable
for at least 0.5 miaute. Evacuate the flexible bag. Connect
tbe probe and place It in the stack, with the tip of the
. probe positioned at the sampling point; purge tbe sampl-
ing line. Next, connect the bag and make sure that all
connections are tight and leak free.
3.2.3 Sample at a constant rate. The sampling: run
should be simultaneous with, and for the same total
length of time as, the pollutant emission rate determin*r
tion. Collection of at least 30 liters (1.00 ft') of sample gas
is recommended; however. «mmn«r volumes may Da
collected. If desired.
3.2.4 Obtain one Integrated flue gas sample during
each pollutant emission rate determination. Within g
hours after the sample is taken, analyze it for percent
CO, and percent Ot using either an Orsat analyzer or a
Fyrite-type combustion gas analyzer. If an Orsat ana-
lyitr is used, it is recommended that the Orsal leak-
check described in Section 5 be performed before this
determination; however, tbe check is optional. Deter-
mine the percentage of the gas that is Ni and CO by sub-
tracting tbe sum of tbe percent CO. and percent Oi
m°||^l*J^C
-------
than (a) OJ percent by volume whan Oi Is less than 15.0
percent or (6) 0.2 percent by volume when Oi la greater
than 15.0 percent. Average the three acceptable values of
percent Oj and report the results to the nearest 0.1
' percent.
4.2.6.3 For percent CO, repeat the analytical proce-
dure until the results of any three analyses differ by no
more than 0.3 percent. Average the three acceptable
values of percent CO and report the result* to toe nearest
0.1 percent.
4.2.7 After the analysis b completed, leak-check
(mandatory) the Orsat analyzer once again, as described
< in Section 6. For the results of the analysis to be valid, the
Orsat analyzer must pass this leak test before and after
the analysis. Note: Although In most Instances only COi
or Oi Is required, it is recommended that both Cut and
Oi be measured, and that Citation 5 in the Bibliography
be used to validate the analytical data. . "
4.3 Multi-Point, Integrated Sampling and Analytical
Procedure.
4.3.1 Both the minimum number of sampling point*
and the sampling point location shall be as specified in
Section 3.3.1 of this method. The use of fewer points than
specified is Mbject to the approval of the Administrator.
4.3.2 Follow the procedures outlined in Sections 4.2.2
through 4.2.7, except for the following: Traverse all
eampirnjj points and sample at each point for an equal
length of time. Record sampling data as shown in Figure
3-3.
8. Xeei-CftMi Proctdunfar Ontl Andyim
Moving an Orsat analyzer frequently causes It to leak.
Therefore, an Great analyzer should be thoroughly teak-
checked on site before the flue gas sample is introduced
Into It. The procedure for leak-checking an Orsat analyser
is:
5.1.1. Bring the liquid level in each pipette up to the
reference mark on the capillary tubing and then close the
pipette stopcock.
8.1.? Raise the leveling bulb sufficiently to bring the
confining liquid meniscus onto the graduated portion of
tbe burette and then close the manifold stopcock.
5.1.3 Record the meniscus position.
5.1.4 Observe the meniscus In the bnrette and tbe
liquid level in the pipette for movement over the next 4
minutes.
S.1.6 For the Orsat analyzer to pass the leak-check,
two conditions must be met.
6.1.5.1 The liquid level in each pipette must not fan.
below the bottom of the capillary tubing during this
4-mlnnte Interval.
5.1.5.2 The meniscus in the burette must not change
by more than 0.2 ml during thls4-minuteinterval.
5.1.6 If the analyur fails the leak-check procedure, all
rubber connections and stopcocks should be cheeked
until the cause of the leak is Identified. Leaking stopcocks
must be disassembled, cleaned, and regressed. I^»»Mne
rubber connections must be replaced. After the anaryter
Is reassembled, the leak-check procedure must 'be
repeated.
RULES AND REGULATIONS
0. CalevlaOont
4.1 Nomenclature.
Mi=Dry molecular weight, g/g-mok (Ib/lb-intfh).
%EA<=< Percent excess air.
%COt=Percent COiby volume (dry bads).
%Oj=Percent Oj by volume (dry bests).
%CO=Percent CO by volume (017 basts).
%Ni=Percont Ni by volume (dry basis).
0.284=Ratio of Oi to Nt In air, v/v.
0.2SO=Molecu!ar weight of N, or CO, divided by 100.
0.320=Moleeular weight of Oj divided by 100.
0.440=Molecular weight of CO, divided by 100. .
6.2 Percent Excess Air. Calculate the percent excess
air (it applicable), by substituting the appropriate
Tames of percent Ot, CO, and N) (obtainedtrom Section
4.1.3 or 4.2.4) into Equation 3-1. .
41771
%O,-0.5%CO
-1,
0.264 %NV( %0,-0.5 %CO)
Equation 3-1
NOTE.— The equation above assumes that ambient
air is used as the source of Oj and that the fuel does not
contain appreciable amounts of Nt (ts do coke oven or
blast furnace gases). For those coses when appreciable
amounts of Ni are present (coal, on, and natural gas
do not contain appreciable amounts of Nt) or when
oxygen enrichment Is used, alternate methods, subject
to approval of the Administrator, are required.
6.5 Dry Molecular Weight. Use Equation 8-2 to
calculate the dry molecular weight of the stack gas
Jtfj=0.4«0(%COi)+0.320(%Oj)-H).280(%>I»+%CO)
Equation 3-2
NOTE.— The above equation does not consider argon
In air (about 0.9 percent, molecular weight of 37.7).
A negative error of about 0.4 percent 'Is introduced.
The tester may opt to include ftrgoa In the analysis using
procedures subject to approval of the Administrator.
1.
i. AUshuUer, A. P. Storage of Gases and Vapors in
Plastic Bags. International Journal of Air and Water.
Pollution. 6:75-81. 1963. "
2. Conner, William D/and J. 8. Nader. Air Sampling
Plastic Baps. Journal of the American Industrial Hy-
giene Association. f«:291-297. 1964.
3. Burrell Manual for 'Gas Analysts; Seventh edition.
Burrell Corporation, 2223 Fifth Avenue, Pittsburgh,
Pa. 15219. 1951.
4. Mitchell. W. J. and M. R. Midfrett. Field Reliability
of the Orsat Analyzer. Journal of Air Pollution Control
Association *6:491-*95. May 1970.
5. Shigehara, R. T., R. M. Neollcht, and W. S. Smith.
Validating Orsat Analysis Data from Fossil Fuel-Fired
Units. Stack Sampling News. 4(2)21-28: August, 1976.
rBMEIAl KEGISTEt, VOL 42, NO. 160—THURSDAY, AUGUST It, 1977
-------
41776
RULES AND REGULATIONS
IMffcon 5—DKTEEHTNATION or PABTICULATB EMISSIONS
FBOM STATIONAET SOURCES
~\~PrtncipU ana Applicability
1.1 Principle, Paniculate matter Is withdrawn tso-
Hnetteally from the source and collected on a glass
fiber film maintained at a temperature In the range of
12u±U* C Q48±25° F) or soon other temperature as
specified by an applicable snbpart of the standards or
approved by the Administrator, U.S. Environmental
Protection Agency, for a particular application. The
partienlate mass, which includes any material that
condenses at or above the filtration temperature, is
determined gravimetrically after removal of unoombined
water.
1.2 Applicability. This method Is applicable for the
determination of paniculate emissions from stationary
sources.
2.1 Sampling Train. A schematlo of the sampling
train used in this method is shown in Figure 5-1. Com-
plete construction details are given in APTD-0681
(Citation 2 in Section 7); commercial models of this
train are also available. For changes from APTD-Q581
and for allowable modifications of the train shown in
Figure 5-1, see the following subsections. _
The operating and maintenance procedures for the
sampling train are described in APTD-0576 (Citation 3
In Section 7). Since correct usage is Important in obtain-
ing valid results, all users should read APTD-0576 and
adopt the operating and maintenance procedures out-
lined in it, unless otherwise specified herein. The sam-
pling train consists of the following components:
FEDERAL REGISTEB, VOL 41. NO. I4O—THURSDAY, AUGUST 18, 1977
-------
RULES AND REGULATIONS
41777
TEMPERA
TURESENSOR
PROBE
SWINGER TRAIN OPTIONAL, MAY BE REPLACED
BY AN EQUIVALENT CONDENSER
P1TOTTUBE
'PROBE
BEVERSE-TYPE
"fltOTTUBt
TEMPERATURE
SENSOR
HEATED AREA
A
THERMOMETER
THERMOMETER
FILTER HOLDER
IMPINGERS ICE BATH
BY-PASS VALVE
CHECK
VALVE
VACUUM
LINE
VACUUM
GAUGE
THERMOMETERS
DRY GAS METER
AIR-TIGHT
PUMP
Fjgure 5 1. Paniculate-sampling train.
ZU PiobeNoi^8t»tatas«teeI or glass with
•burp, tapered leading edge. The angle of toper shall
be SV* *»d the taper •half be on the outside to preserve
• constant internal diameter. The proble nfltrlo 8h&U be
«f the button-book or «Ibow design, unless otherwise
•pacified by the Administrator. If made of •tainless
•tmi_ the noule •hall be constructed from gam^ia^ tnb-
Ing; other materials of construction ma; be used, subject
to the approval of the Administrator. .
A range of noule aises suitable for isokinetic sampling
should be available, e^, OS2 to 1.Z7 cm (M to H in.)—
or larger if higher volume p*mp*lng trains are used—
iivdfiA diameter (ID) n"f**pft in Increments of 0.16 cm
(H« In.). Each noule shall be calibrated according to
the procedures outlined in Section &
2.1.2 Probe Liner. Borosillcato or qnarU glass tubing
with a beating system capable of maintaining a gas tem-
• peratnre at the exit end during sampling of 120±14° C
(248db25° F), or such other temperature as specified by
on applicable subpart of the standards or approved by
the Administrator far a particular application. (Tbe
tester may opt to operate the equipment at a temperature
lower than that specified.) Since the actual temperature
at the outlet of the probe is not usually monitored during
aampling, probes construe ted. according to APTD-0581
and ntUUing the calibration curves of AFTD-0576 (or
calibrated according to the procedure outlined in
APTD-0578) will be considered acceptable.
Either borosilicUe or quarts glass probe liners may be
used tor stack temperatures up to about 480" C ,900° F):
quartz liners shall be used for temperatures between 480
and 900° C (900 and 1.650° F). Both types ol liners may
be used at higher temperatures than specified lor short
periods of time, subject U> the approval of the Adminis-
trator. The softening temperature tor borosilicate is
890° C (1,308° F),and~av quartz it is 1^«° C (2,732° F).
Whenever practical, ever; effort should be made to use
borosfUcate or quartz glass probe liners. Alternatively.
metal liners (e-g., W6 stainless steel, Inooloy 825,' or other
corrosion w»g»g*ni»t imrtytK) made of seamless tuning may
b* used, subject to the approval of the Administrator. •
Z.I3 Pilot Tube. Type 8, as described in Section 2.1
of Method 2, or other device approved by the Adminis-
trator. The pilot tube shall be aliacbed to the prolx (as
•hown In Figure S-l) to allow constant monitoring of the
•tack gas velocity Tbe impact (high pressure) opening
> Mention ol trade names or specific product does not
constitute endorsement by the Environmental Protec-
tion Agoncy.
plane of the pttot tnbe shall be even with or above the
noule entry plane (see Method 2, Figure 2-6b) during
sampling. The Type 8 pilot tnbe assembly shall have a
known coefficient, determined as outlined In Section 4 of
Method 2.
' 2,1.1 Differential Pressure Gauge. Inclined manom-
eter or equivalent dev%c > it
about 1.3 cm 04 In.) from the bottom ol the flask. The
second impinger shall be ol the Oreenburg-Smilb design
with the standard Up. Modifications (e.g.. using flexible
connections between the impingers, using materials
other titan glass, or using flexible vacuum lines to connect
the filter bolder to the condenser) may be used, subject
to the approval of the Administrator. Tbe first and
second impingers shall contain known quantities ol
water (Section 4.1.3). the third shall be empty, and the
fourth shall contain a known weight of silica gel. or
equivalent desiccant. A thermometer, capable of measur-
ing temperature to within 1° C (2° F) shall be placed
at the outlet of the fourth Impinger for monitoring
purposes.
Alternatively, any system that cools the sample gas
stream and allows measurement of the water condensed
and moisture leaving the condenser, each to within
1 ml or 1 g may be used, subject to the approval of the
Administrator. Acceptable means are to measure the
condensed water either gravimeirlcaUy or volumetrically
and to measure the moisture leaving the condenser by:
(1) monitoring the temperature and pressure at the
exit of the condenser and using Daltos's law of partial
pressures; or (2) passing the sample gas stream through
a tared silica gel (or equivalent desiccant) trap with
exit gases kept below 20° C (68° F; and determining
the weight gain.
If means other than silica gel are used to determine
the amount ol moisture leaving th? condenser, it is
recommended that silica gel (or equivalent) still be
used between the condenser system and pump to prevent
moisture condensation in the pump and metering devices
and to avoid the need to make corrections for moisture In
the metered volume.
NOTE.—If a determination of the paniculate matter
collected la the Impingers is desired in addition to mois-
ture content, the impinger system drscribcd above shall
be used, without modification. Individua. Stales or
control agencies requiring this information shall be
contacted as to the sample recovery and analysis ol the
impinger contents.
2.1.8 Metering System. Vacuum gange, leak-free
pump, thermometers capable oi measuring temperature
towlthin3°C(5.4°F),drygas mctercapableol measuring
volume to within 2 percent, and related equipment, as
shown In Figure 6-1. Other metering systems capable of
maintaining sampling rates within 10 percent of iso-
kiuetic and ol determining sample volume* to within 2
percent may be used, subject to the approval o' the
Administrator. When the metering system is used in
conjunction with a pilot tube, the system shall enable
checks oi isokinetic rates.
Sampling trains utilizing raeteringsystems designed for
higher flow rates than that described in APTD-0581 or
APTU-OoTu may be used provided that the specifica-
tions o. this method are met.
2.1.y Barometer. Mercury, aneroid, or other barometer
capable o! measuring atmospheric pressure to within
2.5 nun Ue (0.1 in. llg). In many casts, the barometric
reading may be obtained from a nearby national weather
service station, in which case tbe station value (which a
FEDEtAl CEdSTER. VOL. «. NO. 16O—IHUUDAY,-AUGUST 16, 1977
-------
41778
RULES AND REGULATIONS
the absolute bar^ni^tric pressure) shall be requested and
an adjustment for elevation differences between the
uvaihir station and sampling point shall be applied at n
rat.; of minus i.i mm Hg (0.1 in. Hg) per 30 m (100 ft)
elevation incr-i£» or vice versa Tor elevation decrease.
C'1.10 Gas Density Determination Equipment.
Temperature s>:uor and pressure gauge, as described
in Sections 23 B rid 2.4 of Method 2, and gas analyzer,
if necessary, as •'•scribed in Method 3. The temperature
sensor shall, preferably, be permanently attached to
the pitot tubVr- .unpling probe in a fixed configuration,
such that the f' jl the sensor extends beyond the leading
edge of the pr •» sheath and does not touch any metal.
Alternatively, ibe sensor may be attached just prior
to use i n t he f id. Note, however, that if the temperature
sensor is attached in the field, the sensor must be placed
in an i:itcrfcreco*-free arrangement with respect to the
Type S pilot tube openings (see Method 2, Figure 2-7).
As a second alternative, if a difference of not more than
1 percent in ib? average velocity measurement is to be
introduced, th* winperatnre gauge need not be attached
to the probe cr pitot tube. (This alternative is subject
to the approval of the Administrator.)
2.2 Sample Recovery. The following items are
needed:
2.2.1 Probe-Uner and Probe-Nozzle Brushes. Nylon
bristle brushes with stainless steel wire handles. The
probe brash shall have extensions (at least as long as
the probe) of stainless steel. Nylon, Teflon, or similarly
inert material. The brushes shall be properly sized and
shaped to brush out the probe liner and noule.
2.2.2 Wash Bottles—Two. Glass wash bottles are
recommended: polyethylene wash bottles may be used
at t be option of tbe tester. It is recommended that acetone/
not be stored ic polyethylene bottles for longer than a
month.
2.2.3 Glass Sample Storage Containers. Chemically
resistant, boroaiicate glass bottles, for acetone washes,
600 ml or 1000 ml. Screw cap liners shall either be rubber-
backed Teflon or shall be constructed so as to be leak-free
and resistant to chemical attack by acetone. (Narrow
month glasr. Nettles have been found to be less prone to
leakage.) Alternatively, polyethylene bottles may be
used.
2.2.4 Pelri Dishes. For filter samples, gla::one to glass bottles from metal containers; thus,
acetone blanks shall be run prior to field use and only
acetone with low blank values (<0.001 percent) shall be
" used. In no -i« shall n blank value of greater than 0.001
percent of the weight of act-lone used be subtracted from
vl:e sample »££lu.'
3.3 Analysis. Two reagents are required for the analy-
sis:
3.3.1 Acetone. Same as 3.2.
3.3.2 Desiceant. Anhydrous calcium sulfato, Indicat-
ing type. Alternatively, other types of deslccanu may be
used, subject to the approval of the Administrator. •
4. Procedure
4.1 Sampling. The complexity of this method Is such
that, In order to obtain reliable results, testers should be
trained and experienced with the test procedures.
4.1.1 Pretest Preparation. All the components shall
be maintained and calibrated according to the procedure
described in APTD-0578, unless otherwise specified
herein.
Weigh several 200 to 300 R portions of silica gel In air-tight
containers to the nearest 0.6 g. Record the total weight of
the silica gel plus container, on each container. As an
alternative, the silica gel need not be preweighed, but
may be weighed directly in its impinger or sampling
holder just prior to train assembly.
Check filters visually against light (or irregularities and
flaws or plnhole teaks. Label filters of the proper diameter
on the back side near the edge using numbering machine
Ink. As an alternative, label tbe shipping containers
(glass or plastic petri dishes) and keep the filters in these
containers at all times except during sampling and
weighing.
Desiccate the niters at 20±S.6° C (68*10° F) and
ambient pressure for at least 24 boors and weigh at In-
tervals of at least 6 hours to a constant weight, I.e.,
<0.5 nig change from previous weighing; record results
to the nearest 0.1 ing. During each weighing the filter
must not be exposed to the laboratory atmosphere for a
period greater than 2 minutes and a relative humidity
above 50 percent. Alternatively (unless otherwise speci-
fied by the Administrator), the filters may be oven
dried at 105° C (220° F) for 2 to 3 hours, desiccated for 2
hours, and weighed. Procedures other than those de-
scribed, which account for relative humidity effects, may
be used, subject to the approval of the Administrator.
4.1.2 Preliminary Determinations. Select the sam-
pling site and the minimum number of sampling points
according to Method 1 or as specified by the Administra-
tor. Determine the stack pressure, temperature, and the
range of velocity beads using Method 2; it b recommended
that a leak-check of the pitot lines (see Method 2, Sec-
tion 3.1) be performed. Determine the moisture content
using Approximation Method 4 or its alternatives for
the purpose of making isokinetic sampling rate settings.
Determine the stack gas dry molecular weight, as des-
cribed in Method 2, Section 3.6; if Integrated Method 3
sampling is used for molecular weight determination, the
integrated bag sample shall be taktn simultaneously
with, and for the same total length of time as, the par-
"ticulate sample run.
Select a nozzle size based on the range of velocity heads,
such that it is not necessary to change the nozzle size in
order to maintain isokinetic sampling rates. During the
run, do not change the nozzle size. Ensure that the
proper differential pressure gauge is chosen for the range
of velocity heads encountered (see Section 2.2 of Method
2).
Select a suitable probe liner and probe length such that
all traverse points can be sampled. For large stacks,
consider sampling from opposite sides of the stack to
reduce the length of probes.
Select a total sampling time greater than or equal to
the minimum total sampling time specified in the test
procedures for the specific industry such that (1) the
sampling tune per point is not less than 2 min (or some
greater time interval as specified by the Administrator),
and (2) the sample volume taken (corrected to standard
conditions) will exceed the required minimum total gas
sample volume. The latter is based on an approximate
average sampling rate.
It is recommended that the number of minutes sam-
pled at each point be an integer or an integer plus one-
half minute, in order to avoid timekeeping errors.
In some circumstances, e.g., batch cycles, it may be
necessary to sample for shorter times at the traverse
points and to obtain smaller gas sample volumes. In
these cases, the Administrator's approval must first
be obtained.
4.1.3 Preparation of Collection .Train. During prep-
aration and assembly of the sampling train, keep all
openings where contamination can occur covered until
just prior to assembly or until sampling is about to begin.
Place 100 ml of water in each of the first two unpingcrs,
leave the third impinger empty, and transfer approxi-
mately 200 to 300 g of preweighed silica gel from Its
container to the fourth impinger. More silica gel may bo
used, but care should be taken to ensure that it is not
entrained 'and carried out from tbe impinger during
sampling. Place tbe container In a clean place for later
use in the sample recovery. Alternatively, the weight of
the silica gel plus impinger may be determined to the
nearest 0.5 g and recorded.
Using a tweezer or clean disposable surgical gloves,
place a labeled .(identified) and weighed filter in tbe
filter holder. Be sure that the filter is properly centered
and the gasket properly placed so as to prevent the
sample gas stream from circumventing the Alter. Check
the niter for tears after assembly is completed.
When glass liners are used, install the selected nozzle
using a Viton A O-ring when stack temperatures are
less than 2>JO° C (500° F) and an asbestos string gasket
when temperatures are higher. See APTD-0576 for
aaetatls. Other connecting systems using either 316 stain
less-steel or Teflon ferrules may be used. When metal
liners are used, Install the nozile as above or by a leak-
free direct mechanical connection. Mark the*probe with
heat resistant tape or by some other method to denote
tbe proper distance into tbe stack or duct for each sam-
pling point.
Set up the train as In Figure 6-1, usfng (If necessary)
a very light coat of silicone grease on all ground glass
Joints, greasing only the outer portion (see APTD-0576)
to avoid possibility of contamination by the silicone
grease. Subject to the approval at the Administrator, a
glass cyclone may be used between the probe and finer
bolder when the total- paniculate catch Is expected to
exceed 100 mg or when water droplets are present In tbe
stack gas.
Place crushed ice around tbe Impingers.
4.1.4 Leak-Check Procedures.
4.1.4.1 Pretest Leak-Check. A pretest leak-check is
recommended, but not required. If the tester opts to
conduct the pretest leak-chock, the following procedure
shall be used.
After the sampling train has been assembled, turn on
and set the filter and probe heating systems at the desired
operating temperatures. A Dow time for the temperatures
tostabiliie. If a Vlton A O-rtng or other leak-free connec-
tion Is used In assembling the probe noule to the probe
liner, leak-check the train at the sampling site by plug-
plug-
. Hg)
,
ging the nozzle and pulling a 380 nun Hg (15 in.
vacuum.
NOTE.— A lower vacuum may be used, provided that
It Is not exceeded during the test.
If an asbestos string is used, do not connect the probe
to the train during tUe leak-check. Instead, leak-check
tbe train by first plugging the inlet to tbe finer bolder
(cycldne, if applicable) and pulling a 380 mm Bg (15 In.
Hg) vacuum (see Note immediately above). Then con-
nect the probe to the train and leak-check at about 25
mm Hg (lln. Hg) vacuum; alternatively, tbe probe may
be leak-checked with the rest of tbe sampling train, in
one step, at 380 mm Hg (15 In. Hg) vacuum. Leakage
rates in excess of 4 percent of the average sampling rate
or 0.00057 m'/niin (0.02 elm), whichever is less, are
unacceptable.
Tbe following leak-check Instructions for the «ampM»»«
train described in APTD-0576 and APTD-0681 may be
helpful. Start tbe pump with bypass valve fully open
and coarse adjust valve completely closed. Partially
open the coarse adjust valve and slowly close the bypass
valve until the desired vacuum is reached. Do not reverse
direction of bypass valve; this will cause water to back
up into the filter bolder. If the desired vacuum Is ex-
ceeded, either leak-check at this higher vacuum or end
tbe leak check as shown below and start over.
When the leak-check is completed, first slowly remove
the plug from the inlet to the probe, filter bolder, or
cyclone (if applicable) and immediately turn off the
vaccum pump. This prevents the water in the impingers
from being forced backward into the filter holder and
silica gel from being entrained backward into tbe third
impinger.
4.1.4.2 Leak-Checks During Sample, Run. If, during
the sampling run, a component (e-g., filter assembly
or impinger) change becomes necessary, a leak-check
shall be conducted immediately before tbe change is
made. The leak-check shall be done according to the
procedure outlined in Section 4.1 .4.1 above, except that
It shall be done at a vacuum equal to or greater than tbe
maximum value recorded up to that point in tbe test.
If the leakage rate is .found to be no greater than 0.00057
mVmin (0.02 cfiu) or 4 percent of the average sampling
rate (whichever is less), tbe results are acceptable, and
no correction will need to be applied to the total volume
of dry gas metcred; if, however, a higher leakage rate
is obtained, the tester shall either record the leakage
rate and plan to correct the sample volume as shown in
Section 0.3 of this method, or shall void the sampling
run.
immediately after component changes, leak-checks
are optional; if such leak-checks are done, tbe procedure
outlined in Section 4.1.4.1 above shall be used.
4.1.4.3 Post-test Leak-Check. A leak-check is manda-
tory at the conclusion of each sampling run. The leak-
check shall be done in accordance with the procedures
outlined in Section 4.1.4.1. except that it shall be con-
ducted at a vacuum equal to or greater than the maxi-
mum value readied during the sampling run. If the
leakage rate is found to be no greater than 0.00057 ms/min
(0.02 cfm) or 4 percent of the 'average sampling rate
(whichever is less), the results are acceptable, and no
correction need be applied to the total volume, of dry gas
motcrcd. If, however, a higher leakage rate is obtained,
the tester shall either record tbe leakage rate and correct
the sample volume as shown in Section 6.3 of this method,
or shall void tbe sampling run.
4.1.5 Paniculate Train Operation. During the
. sampling run, maintain an Isobinetic sampung rate
(within 10 percent of true isokinetic unless otherwise
specified by the Administrator) and a temperature
around the tiller of 120±14° C (248±25° F), or such other
temperature as specified by an applicable snbpart of the
standards or approved by the Administrator.
For each run, record the data required on a data sheet
such as the one shown in Figure 5-2. Be sure to record tbe
initial dry gas meter reading.' Record the dry gas meter
readings at the beginning and end of each sampling time
increment, when changes in flow rates an made, Defore
and after each leak cheek, and when sampling is baltedi
FEDERAL REGISTER, VOL 42, NO. 160—THURSDAY, AUGUST 16, 1977
-------
RULES AND R'EGULATO&SS
41779
Take other readings required by Figure 5-2 at least once
at each sample point during each time Increment and
additional readings when significant changes (20 percent
variation in velocity head readings) necessitate addi-
tional adjustment in flow rate, level and wro the
manometer. Because the manometer level and eero may
drift due to vibrations and temperature changes, make
periodic cheeks during the traverse.
Clean the portholes prior to th* test ran to mlntaSB»
the chance of sampling deposited rnnterttO. WSssln
sampling, remove the noztle cap, verify that -the Slier
and probe beating systems an np to temperature, and
that the pilot tube and probe are properly positioned.
Position the nozzle at the first traversepolnt with the tip
pointing directly Into the gas stream. Immediately start
the pomp and adjust the flow to laoUnetts conditions.
Nomographs are available, which aid In the rapid adjust-
ment of the tsoHnetio sampling rate without excessive
computation*. These nomographs are designed for use
whan the Type 8 pilot tube coefficient is O.S5±0.02, and
the stack gas equivalent density (dry molecular weight)
to equal to 29=fc4. APTD-0576 details the procedure for
using the nomographs. If C, and Ut are outside the
above stated ranges do not use the nomographs unless
appropriate steps (see Citation 7 in Section 7) are taken
to compensate for the deviations.
PLANT
LOCATION.
OPERATOR,.
DATE
RUN NO. _
SAMPLE BOX N0._
METER BOX DO. _
METEBAHq
CFACTOR
AMBIENT TEMPERATURE.
BAROMETRIC PRESSURE.
ASSUMED MOISTURE, X_
PROBE LENGTH, m (ft)
PITOT TUBE COEFFICIENT, C.
SCHEMATIC OF STACK CROSS SECTION
•NOZZLE IDENTIFICATION NO..
AVERAGE CALIBRATED NOZZLE DIAMETER, en M.
PROBE HEATER 5ETTIMC
LEAK RATE, m3/ram.(efra)
PROBE LINER MATERIAL '
STATIC PRESSURE, mm Hi tin. Kg),.
FILTER NO.
TRAVERSE POINT
.NUMBER
• '-' :
— ' • *
':• . .' .
TOTAL
SAMPLING
TIME,
(01. min.
'
1
AVERAGE . ,
VACUUM
mmHg
(in. Ha)
', '
'•__'' . 1 ' " '
--_• ,« . ; •
f'~' ' ,
-; . ; .. ;
STACK
TEMPERATURE
(Tsl
•C ("Fl
'
-
'••'• :•!•..".'
'•-•
' '. ' " "
VELOCITY
HEAD
(AP$).
mmf.fn.lHjO
.,-
"'
i " ':
,
PRESSURE
DIFFERENTIAL
ACROSS
ORIFICE
' 'METER :
nmUjO '
(in.H20)
.. ,."„.'
.,.,-,•. • '
'., •
- ' V •
'-.• ' ••
' j
CAS SAMPLE
VOLUME .
i^lltS)
„;•.
• ..-. : • '-.
'.-, --
., •
GAS SAMPLE TEMPERATURE
AT DRY GAS METER
INLET
•C <»F)
•' '• :
Avg.
OUTLET
•C («F>
•
Avg.
Avg. • .
FILTER HOLDER
.TEMPERATURE.
•C ("F)
-.- • .1';
-i • . .<•••/
TEMPERATURE
-'. Of GAS '
- LEAVING
CONDENSER OR
LAST IMPINGER.
'Cl8?!
. ,
\
1 •- .
'-L.I' •'
When the stack is under significant negative pressure
(height of implnger stem), take care to close the coarse'
adjust valve before inserting the probe into the stack to
prevent water from backing into the filter bolder. If
necessary, the pump may be turned on with the coarse
adjust valve closed.
When the, probe is In position, block oB the openings
around the probe and porthole to prevent unrepre-
sentative dilution of the gas stream.
Traverse the stack cross-section, as required by Method
1 or as specified by the Administrator, being careful not
to bump the probe nozzle into the stack walls when
sampling near the walls or when removing or Inserting
the probe through the portholes; this minimizes the
chance of extracting deposited material.
During the test run, make periodic adjustments to
keep the temperature around the filter holder at the
proper level: add more ice and. If necessary, salt to
maintain a temperature of less than 20° C (GS° F) at the
condenser/silica gel outlet. Also, periodically check
the level and zero of the manometer.
If the pressure drop across the filter becomes top high,
making isokinetic sampling difficult to maintain, the
filter may be replaced in the midst of a sample run. It
is recommended that another complete filter assembly
be used rather than attempting to change the filter itself.
Before a new filter assembly is installed, conduct a leak-
check (see Section 4.1.4.2). The total paniculate weight
shall include the summation of all filter assembly catches.
A single train shall be used for the entire sample run,
except in cases where simultaneous sampling is required
in two or more separate ducts or at two or more different
locations within the same duct, or, in cases where equip-
ment failure necessitates 8 change of trains. In all other
situations, the use of two or more trains will be subject to
the approval of the Administrator.
Figure 5-2. Participate field data.
Note that when two or more trains are used, separate
analyses of the front-half and (If applicable) impinger
catches from each train shall be performed, unless identi-
cal nozzle sizes were used on all trains, in which case, the
front-half catches from the individual trains may be
combined (as may the impinger catches) and one analysis
of front-half catch and one analysis of Impinger catch
may be performed. Consult with the-Admmistrator for
details concerning the calculation of results when two or
more trains are used.
At the end of the sample run, turn oft the coarse adjust
valve, remove the probe and nozzle from the stack, turn
off the pump, record the final dry gas meter reading, and "
conduct a post-test leak^heck, as outlined in Section
4.1.4.3. Also, leak-check the pitot lines as described in
Method 2, Section 3.1; the lines must pass this leak-check,
in order to validate the velocity head data.
4.1.6 Calculation of Percent Isokinetic. Calculate
percent isokinetic (see Calculations, Section 6f to deter-
mine whether the run was valid or another test run
should be made. If there was difficulty in maintaining
isokinetic rates due to source conditions, consult with
the Administrator for possible variance on the isokinetic
rates.
4.2 Sample Recovery. Proper cleanup procedure
begins as soon as the probe is removed from the stack at
the end of the sampling period. Allow the probe to cool.
When the probe can be safely bandied, wipe off all
external paniculate matter near the tip of tne probe
nozzle and place a cap over it to prevent losing or gaining
participate matter. Do not cap off the probe tip tightly
while the sampling train is cooling down as this would
create a vacuum in the filter holder, thus drawing water
from the impingers into the filter holder.
Before moving the sample train to the cleanup site,
remove the probe from the sample train, wipe on the •
sillcone grease, and cap the open outlet of the probe. Be.
careful not to lose any condensate that 'mieht be present;
Wipe ofl the silicone grease from the filter inlet where the
probe was fastened and cap it. Remove the umbilical
cord from the last impinger and cap the impinger. If a
flexible line is used between the first teptaper or con-
denser and the filter holder, disconnect the fine at the
filter bolder and let any condensed water or Liquid
drain into the impingers or condenser. After wiping off
the silicone grease, cap ofl the filter holder outlet and
impinger inlet. Either ground-glass stoppers, plastic
caps, or serum caps may be used to close these openings.
Transfer the probe and filter-impinger assembly to '.ho
cleanup area. This area should be clean and protects
from the wind so that the chances oi' toi-iuminaiir^' or
losing the sarcple will be minimized.
Save a portion of the acetone used for o'.r-rtnup. as a
blank. Take 200ml of this acetone din:c;]v fr/tii In-,1 wi:-h
bottle being used and place it in a glass Msiple container
labeled "acetone Wank."
Inspect the train prior to and durinp di-:a3*r:nWy and
note any al'nonnal conditions. Treat the samples as
follows:
Container \o. I. Carefully remove the filter from the
filter holder and place it In its identified petri dish con-
tainer, tise a pair of tweezers and/or cleja disposable
surgical gloves to handle the filter. If it is necessary to
fold the filler, do so such that the parr.ruiate cake is
inside the f&H. Carefully transfer to the pciri dish any
paniculaie mauer and/or filter fibers wL>a adhere to
the filter holder gasket, by using a dry cylon bristle
brush and.-'or a sharp-edged blade. Seal the container.
Container \o. I. Taking care to see tea: dust on the
outside of the probe or other exterior sonices does no:
get inio the sample, quantiiatively roe-over parUcuia'-e
matter or ar.jr conJensate from the probe tazzle, probe
FEDERAL REGISTER, VOL. 42, NO. 160—THURSDAY, AUGUST 18, 1977
-------
41780
BUtES AND REGULATIONS
filling, probe Siner, and front hall of tin fitter bolder by
washing tbw components with soutane and plating the
wash in a gtass container. Distilled water may to used
instead of acetone when approved by the Administrator
and snail be «d wbeo specified by the Administrator;
in these cases, save a water blank and follow the Admin-
istrator's directions on analysis. Perform the acetone
rinses as follows:
Carefully r*s:ove the probe noule and clean the inside
surface by rirjinx with acetone from a wash bottle and
brushing wi'h a nylon bristle brush. Brush until the
acetone tin'? shows no visible particles, after which
make a final rinse of the inside surface with acetone.
Brush fl"' rinse the inside parts of the Bwagtlok
fitting wit . sc»tone in a similar way until no visible
panicles r.n^in.
Rinse the probe liner with acetone by tilling and
rotating the probe while s/iuirliiif* acetone into its upper
end so that an inside surfaces will be wetted with aoe-
tone. l*t the scetone drain from the lower end Into the
snicple roiHsfr-T. A funnel (glass or polyethylene) may
be used 10 a:j in transferring liquid washes to the con-
tainer. Follow the acetone rinse with a probe brush.
Hold the prot« in an inclined position, spurt acetone
into the up|*r end as the probe brush Is being pushed
with a twisting action through the probe; hold a sample
container underneath the lower end of the probe. and
catch aiiy acetone, and paniculate matter which Is
brushed fros the probe. Hun the brush through tin
probe three uses or more until no visible paniculate
matter is carr.td out with the acetone or until none
remains in ihe prone Hner on visual inspection. With
stainless steel or other metal probes, run the brash
thrcuah in \t? above prescribed manner at least six
limss'tincc r-^-al proles have small crevi? container so that acetone will not leak: •
out when it is shipped to the laboratory. Mark the
height of tbe £uid level to determine whether or not
leakage occurred during transport. Label the container
to clearly ider.ufy its contents.
Container -Vo. 3. Note t he color of the indicating silies
Eel to deterameif it has been completely spentand make
a notation ofi:-* condition. Tramfer the silica gel from
the foiirth ta;pii!irer to its original container and seal.
A funnel may make it easier to pour the silica pel without
spiUmg. A rubber politoii.au may be used as an aid in
removing t!ie silii-a eel from the improper. It is not
necessary to i&cove the small amount of dust panicles
that n;ay.adh«re to the impinger wall and are diflk-uit
to remove. £ir.<*e the gain in weight is to be used for
moisr.ire cak-.Nations, do not use any waur or other
liquids to tra/o.Vr the silica gel. If a balance is available
in the field, fc-ow the procedure for container No. 3
in Section 4.3.
ImpingfT ifc.'rr. Treat the impuigers as follows: Make
ft notation of ar.y color or lilm in the liquid catch. Measure
the liquid wt:ch is in the lirst three iiupingers to within
a. 1 ml by us:.-.? a graduated cylinder or by weighing it
to within •*('.•' B by using a balance (if one is available). ,
Record the voUime or weight of liquid present. This
information is required to calculate the moisture content
of the effluent gas.
Discard the liquid after measuring and recording the
volume or weight, unless analysis of the impioger catch
is required is« Note, Section 2.1.7).
If a different type of condenser is used, measure the
amount of moisture condensed either volujuetrkally or
gravimetricaiiy.
Whenever possible, containers should be shipped in
such a way that they remain upright at all times.
4.3 Analysis. Record the data required on a sheet
such as the one shown in. Figure A-3. Handle each sample
container as follows: . ,.
Container .Vo. /. Leave the content* in the shipping
container or transfer the filter and any loose paniculate
from the sample container to a tared glass weighing dish-
Desiccate for 24 hours in a desiccator containing anhy-
drous calcium sulfate. Weigh to a constant weight and
report the results to the nearest 0.1 mg. For purposes 01
this Section, «.3, the term "constant weight' means a
difference of no more than 0.6 mg or 1 percent of total
weight less tare weight, whichever Is greater, between
two consectrjve weighings, with no lea than 6 boors of
desiccation time between weighings.
Rent.
Date.
Run Mo..
Filter No..
Amount liquid lost during transport
Acetone blank volume, ml
Acetone wash volume, ml
Acetone blank concentration, mg/mg (equation 5-4).
Acetone wash blank, mg (equation 5-5)
CONTAINER
NUMBER
1
2
TOTAL
WEIGHT OF PARTICULAR COLLECTED,
mg
FINAL WEIGHT
^xd
TARE WEIGHT
^>~<^
Less acetone blank
Weight of paniculate matter
WEIGHT GAIN
-
FINAL
INITIAL
UQUID COLLECTED
TOTAL VOLUME COLLECTED
VOLUME OF LIQUID
WATER COLLECTED
IMPINGER
VOLUME,
ml.
SILICA GEL
WEIGHT,
9
g'F mi
CONVERT WEIGHT OF WATER TO VOLUME BY DIVIDING TOTAL WEIGHT
INCREASE BY DENSITY OF WATER (10/ml);
INCREASE, g a
1 g/ml
Figure 5-3. Analytical data.
ftOERAL BEGISTHt, VOL 42. NO. 160—THUISDAV, AUGUST >»*, 1977
-------
RULES AND REGULATIONS
41781
Alternatively, the sample may be oven dried at 105° C
(220° F) for 2 to 3 hours, cooled In the desiccator, and
weighed to a constant weight, unless otherwise specified
by the Administrator. The tester may also opt to oven
dry the sample at 105° C (220° F) for 2to3hoars,weigh
the sample, and use this weight as a final weight.
Container No. 8. Note the level ofllquid In the container
and confirm on the analysis sheet whether of not leakage
occurred during transport. If a noticeable amount of
leakage has occurred, either void the sample or use
methods, subject to the approval of the Administrator,
to correct the final results. Measure the liquid in this
container either volumetrlcally to ±1 ml or gravi-
metricaUy to ±0.5 g. Transfer the contents to a tared
250-ml beaker and evaporate to dryness at ambient
temperature and pressure. Desiccate for 24 hours and
weigh to a constant weight. Report the results to the
nearest 0.1 mg.
Container No. S. Weigh the spent silica gel (or silica gel
plus Implager) to the nearest 0.5 K using a balance. This
step may be conducted in the field.
Acetone -Blank" Container. Measure acetone In this
container either volumetrically or gravimetrlcally.
Transfer the acetone to a tared 250-ml beaker and evap-
orate to dryness at ambient temperature and pressure.
Desiccate for 24 boon and weigh to a contsanC weight
Beport the results to the nearest Oa mg.
No«.—At the option of the tester, the contents of
Container No. 2 as well as the acetone blank container
may be evaporated at temperatures higher than ambi-
ent. It evaporation Is done at an elevated temperature,
the temperature must be below the boiling point of the
solvent; also, to prevent "bumping," the evaporation
process must be closely supervised, and the contents of
the beaker most be swirled occasionally to maintain an
even temperature. Use extreme care, as acetone Is highly
flammable and has a low flash point.
5. CaUonttm
Mointain a laboratory log of all calibrations.
5.1 Probe Nonle. Probe nozzles shall be calibrated
before their Initial use in the field. Using a micrometer,
measure the inside diameter of the nozzle to the nearest
0.025 mm (0.001 In.). Make three separate measurements
using different diameters each time, and obtain the aver-
age of the measurements. The difference between the high
and low numbers shall not exceed 0.1 mm (0.004 in.).
When nozzles become nicked, dented, or corroded, they
shall be reshaped, sharpened, and recalibrated before
use. Each nozzle shall be permanently ud uniquely
identified.
5.2 Pilot Tube. The Type 8 pltot tube assembly shall
be calibrated according to the procedure outlined in
Section 4 of Method 2.
5.3 Metering System. Before Its initial me In the field,
the metering system shall DC calibrated according to the
procedure outlined In APTD-0576. Instead of physically
adjusting the dry gas meter dial readings to correspond
to the wet test meter readings, calibration factors may be
used to mathematically correct the gas meter dial readings
to the proper values. Before calibrating the metering sys-
tem, it Is suggested that a leak-check be conducted.
For metering systems having diaphragm pumps, the
normal leak-check procedure will not detect leakages
within the pump. For these cases the following leak-
check procedure is suggested: make a 10-mlnute calibra-
tion run at 0.00057 m >/min (0.02 cfm); at the end of the
run, take the difference of the measured wet test meter
and dry gas meter volumes: divide the difference by 10,
to get the leak rate. The leak rate should not exceed
0.00057 m >/min (0.02 elm).
After each field use, the calibration of the metering
system shall be checked by performing three calibration
runs at a single, Intermediate orifice setting (based on
the previous field test), with the vacuum set at the
maximum value reached doting the test series. To
adjust the vacuum, insert a valve between the wet test
meter and the inlet of the metering system. Calculate
the average value of the calibration factor. If the calibra-
tion has changed by more than 5 percent, recalibrate
the meter over the full range of orifice settings, as out-
lined in APTD-0576.
Alternative procedures, e.g., using the orifice meter
coefficients, may be used, subject to the approval of the
Administrator.
NOTE.—If the dry gas meter coefficient values obtained
before and after a test series differ by more than 5 percent,
the test series shall either be voided, or calculations for
the test series shall be performed using whichever meter
coefficient value (I.e.. before or after) gives the lower
value of total sample volume.
5.4 Probe Beater Calibration. The probe healing
system shall be calibrated before Its Initial use In the
field according to the procedure outlined in APTD-0576.
Probes constructed according to APT1MB81 ne*d not
be calibrated If the calibration curves in APTD-0578
are used.
5.5 Temperature Gauges. Use the procedure In
Section 4J of Method 2 to calibrate In-stack temperature
gauges. Dial thermometers, such as are used for tbe dry
gas meter and condenser outlet, shall be calibrated
against mercury-in-glass thermometers.
5.6 Leak Check of Metering System Shown In Figure
5-1. That portion of the sampling train from the pomp
to the orifice meter should be leak checked prior to initial
use and after each shipment. Leakage after the pump will
result in less volume being recorded than Is actually
sampled. The following procedure is suggested (see
Figure 5-4): Close the main valve on the meter box.
Insert a one-hole rubber stopper with rubber tubing
attached Into the orifice exhaust pine. Disconnect ana
vent the low side of the orifice manometer. Close ofl the
low side orifice tap. Pressurize the system to 13 to 18 on
(5 to 7 In.) water column by blowing Into the rubber
tubing. Pinch off the tubing and observe the manometer
tor one minute. A loss of pressure on the manometer
Indicates a leak in the meter box; leaks, U present, must
be corrected. . .
6.7 Barometer. Calibrate against a mercury barom-
eter.
6. Calmlvliont
Carry out calculations, retaining at least one extra
decimal figure beyond that of the acquired data. Round
off figures after the final calculation. Other forms of the
equations may be used as long as they give equivalent
results.
RUBBER
TUBING
RUBBER
STOPPER
ORIFICE
VACUUM
GAUGE
BLOW INTO TUBING
UNTIL MANOMETER
READS S TO 7 INCHES
WATER COLUMN
ORIFICE
MANOMETER
Figure 5-4. Leak check of meter box.
B. 1 Nomenclature
A, —Cross-sectional area of nozzle, m' (ft1).
£— -Water vapor in the gas stream, proportion
by volume.
C, -Acetone blank residue concentrations, mg/g.
c, —Concentration of paniculate matter in stack
gas, dry basis, corrected to standard condi-
tions, g/dscm (g/dscf).
/ —Percent of isokinetlc sampling. .
L, —Maximum acceptable leakage rate for either a
pretest leak check or for a leak check follow-
ing a component change; equal to 0.00057
m'/mln (0.02 cfm) or 4 percent of the average
sampling rate, whichever is less.
Lt — Individual leakage rate observed during the
leak check conducted prior to the *'<">"
component change ((=1, 2, 3 .... n),
m'/mln (cfm).
L, -Leakage rate observed during the post-test
leak check, m'/mln (cfm).
m. —Total amount of paniculate matter collected,
mg.
U, —Molecular weight of water, 18.0 g/g-mole
(18.0 Ib/lb-mole).
•. -Mass of residue of acetone after evaporation,
TTlg,
Pb« -Barometric pressure at the sampling site,
mm H( (in. fig).
Pi — Absolute stack gas pressure, mm IIg (in.Hg):
J*M4 —Standard absolute pressure 700 mm Bg
(28.92 In. Hf).
R • = Ideal gas constant, 0.06236 mm Hg-m'/°K-g-
mole (21.85 in. Hg-ft>/°R-lb-mole).
Tm —Absolute average dry gas meter temperature
(see Figure 5-2), °K (°R).
T, —Absolute average stack gas temperature (see
Figure 5-2), °K(°R).
T,a —Standard absolute temperature, 293° K
(528° R).
Vm —Volume of acetone blank, mL
V.. =Volume of acetone used In wash, ml.
Vi,=Total volume of liquid collected in unpingers
and silica gel (see Figure 5-3), ml.
V«=Volume of gas sample as measured by dry gas
meter, dcm (dcf).
V.(.u)=Volume of gas sample measured by the dry
gas meter, corrected to standard conditions,
dscm (dscf).
V.(.rj)=Volume of water vapor in the gas sample,
corrected to standard conditions, scm (get).
V".=Stack gas velocity, calculated by Method 2,
Equation 2-0, using data obtained from
Method 5, m/sec (ft/sec).
IP.=Weight of residue in acetone wash, mg.
X=Dry gas meter calibration factor.
A//=Average pressure differential across the orifice
meter (see Figure 5-2), mm HiO (in. HiO).
P.= Density of acetone, mg/ml (see label on
bottle).
p.= Density of water, 0.9982 g/ml (0.002201
Ib/ml).
9=Total sampling time, min.
0j=Sampling time interval, from the beginning
of a run until the. first component change,
min.
fc^Sampling time Interval, between two suc-
cessive component changes, beginning with
the Interval between the first and second
changes, min.
0,=Sampling time Interval, from the final 'n">>
component change until the end of the
sampling run, min.
13.6= Specific gravity of mercury.
GO=Sec/min.
100= Conversion to percent.
6.2 Average dry gas meter temperature and average
orifice pressure drop. See data sheet (Figure 5-2).
6.3 Dry Gas Volume. Correct the sample voliime
measured by the dry gas meter to standard conditions
(20" C, 760 mm Hg or 08° f, 29.92 in. Hg) by using
Equation 5-1. .-•
Equation S-l
FEDERAL REGISTER, VOL 42, NO. 160—THURSDAY, AUGUST 18, 1977
-------
41782
BUlfS AND REGULATIONS
'Kftmn Hg far metric onlU
—17.64 "Rfln. Hg fir English, unite
Norm.—Eqnstlon 6-1 can be and fc§ vtitteD ante*
tbe leakage rate observed during any of tbe mandatory
Jeek checks (l.e-, the post-test leekTc&eck of leak check)
condneted prior to component changes) exceeds £.. If
•, or & exceed* £„ Equation 6-1 must be modified at
<•) Case I. No component changes mad* daring
sampling ran. la this cose, replace V. ID Equation 5-1
with tbe expression;
(b) Case tt. On* or more component changes made
during tbe sampling run. In this owe, replace V. in
Equation 6-1 by the expression:
I
r,,-(£,-
and rabstitute only tor those leakage rate* (Z« ot £»)
which exceed I*.
6.4 Volume of water vapor.
Equation 8-2
Non.—In artorated or water droplet-laden pe
•tremns, two calculations oHhemotetore content of the
gtaek wa shall be made, one from the tmpfnger analysis
(Equation 5-3), and a second bom the assumption of
saturated conditions. Tbe lover of the two values of
B. aball be considered correct. Tbe procedure (or deter-
mining tbe moisture content based upon assumption of
Batorated conditions Is given In (he Not* of Section 1J
at Metbod 4. For tbe purposes of this method, the avenge
(tack gas temperature from Figure 6-4 may be used to
make oils determination, provided that the accuracy of
the uvelack temperature sensor l»±l°C (ft).
«.« Acetone Blank Concentration.
C.=
6.7 Acetone Wash Blank.
Equation 5-4
6.8
Equation (-5
Total Paniculate Weight. Determine the total
partteulate catch from the sum of the weights obtained
from containers 1 and 2 less tbe acetone Wank (Be Figure
S-8X Non.—Refer to Section 4.1.6 toaatittin eafculatton
of results Involving two or more fitter assemblies or two
or more sampling frains.'
6.9 Particulate Concentration:
c.= (0.001 g/mg)
640 Conversion Factors:
Jfttmx
To
rhere:
K,=0.001833 mi/ml for metric units
-0.04707 tWml far English units.
6£ Moisture Content -
n *l»(«tj)
Multiply By
EcjoationS-s
g/ft«
g/ft*
m«
&
e/m<
'1ft, 48
2.205X10-*
3S.31
6.11 laoklnetlo Variation.
cUJ-1 Calculation From Raw Data.
where:
.Ka-0.003454 mm Bg-m'/ml-'K for metric units.
-0.002069 in. IIg-ff/ml-°B for English units.
6.11.3 Calculatioa From latennedlato values. •
S. VeDaro, R. F. A Survey of Commerolally Available
Insteumentatlon For the MAflfflrii™*">t of Low-Ranee
Gas Velocities. U.S. Environmental Protection Agency,
Knxlasion • Measurement Brancn. ReBeoreii Xnaoua •
Park, N.C. November, 1976 (unpubliihed paper).
9. Annual Book of A8TM Standards. Fart 26. Oasoom
Fuels; Coal and Coke; Atmospheric Analysis. American
Society tat Testing and Materials. Philadelphia, Pa.
1974. pp. 617-622.
Equation 5-8
where:
jfi=4.320 for metric units
-0.094JO for English units.
6.13 Acceptable Results. If 90 percent < 7<110 per-
cent, tbe results are acceptable. If the results are tow In .
comparison to the standard and / Is beyond the accept-
able range, or, if / is less than 90 percent, the Adminis-
trator may opt to accept the results. Use Citation 4 to
make ] udgments. Otherwise, reject the results and repeat
toe test.
1. Addendum to Specifications for Incinerator Testing
at Federal Faculties. PH8, NCAPC. Doe. 6.19W.
t. Martin, Robert M. Construction Details of Iso-
kJnette Source-Sampling Equipment. Environmental
Protection Agency. Research Triangle Park, N.C.
APTD-0581. April, 1971.
S. Rom, Jerome >. Maintenance, Calibration, and
Operation of IsoMnrtlc Source Sampling Equipment.
Environmental Protection Agency. Research Triangle
Park. N.C. APTIXB70. March. 1972.
4. Smith, W. B.. B. T. Shigehara, and W. F. Todd.
A Method of Interpreting Stack Sampling Data. Paper
Presented at the 63d Annual Meeting of the Air Pollu-
tion Control Association, St. Louis, Mo. June 14-19,
1970
8. Smith, W. B^et aL Stack Oas Sampling Improved
and Simplified With New Equipment. APCA Paper
it Specifications tor Incinerator Testing at Federal
Fteffltiea. PHB.NCAPO. 1967.
7. BUgebara,^. T. Adjustments m tbe EPA Humo-
•rapb lor Different Pltot Tube Coefficients and Dry
jfcjfri-rilnr Weights. Stack Sampling News M-ll.
October, 1974.
FEDEIAL lEGISTEfl, VOL 4J, NO. 160—THUtSDAY, AUGUST -li. 1977
-------
THOO B—VISUAL DBTEEMlNAnOt* O» THE
>PACITT or XUISSIONS FROM BTATIONABT
(OCBCE3 10 . '
rfany stationary sources discharge visible
isslons Into the atmosphere; these emis-
03 ore usually In the shape of a plume.
13 method Involves the determination of
ime opacity by qualified observers. The
•thod Includes procedures for the training
d certification of observers, and procedures
be used In the field for determination of
jme opacity. The appearance of a plume aa
iwed by an observer depends upon a num-
r of variables; *ome of which may be con-
>UabIe and eome of which may not be
atrollable In the field. Variables which can
controll&a.to an extent to which they no
nger exert a significant Influence upon
ome appearance Include: Angle of the ob-
rver with respect to the plume; angle of the
'server with respect to the sun; point of
uanratlon of attached and detached steam
ume; and angle of the observer with re-
ect to a plume emitted from a rectangular
ack with • large length to width ratio. The
ethod Includes specific criteria applicable
> these variables.
Other variables which may not be control-
bio in the field are luminescence and color
ntrast between the plume and the back-
ound against which the plume is viewed.
less variables exert an Influence upon the
ipearance of a plume as viewed by an ob-
rver. and can affect the ability of the ob-
rver to accurately assign opacity values
' the observed plume. Studies of the theory
; piume opacity and field studies have dem-
istrated that a plume is most visible and
•esents the greatest apparent opacity when
awed against a contrasting background; It
Hows from this, and Is confirmed by field
lals, that the opacity of a plume, viewed
ider conditions where a contrasting back-
ound Is present can' be assigned with the
•eatest degree of accuracy. However, the po-
ntlal for a positive error la also the. greatest
ben a plume Is viewed under such contrast*
g conditions. Under conditions presenting
less contrasting background, the apparent
>adty of a plume la less and approaches
ro as the color and luminescence contrast
crease toward zero. As a result, significant
igative bias and negative errors can be
Ado when a plume la viewed under less
intrastlng conditions. A negative bias do-
eases rather than Increases the possibility
at a plant operator will be cited for a ylo-
tion of opacity standards due to observer
ror.
Studies have been undertaken to determine
le magnitude of positive errors which can
a made by qualified observers while read-
>g plumes under contrasting conditions and
sing the procedures set forth In this
lethod. The results of these studies (field
•lals) which Involve a total of 769 sets of
S readings each are as follows:
(I) For black plumes (133 sets at a smoke
enerator), 100 percent of the sets were
:ad with a positive error1 of less than 7.5
ercent_opaclty: 89 percent were read with
positive error of less than 5 percent opacity.
(2) For white plumes (170 sets at a smoke
enerator, 168 seta at a coal-fired power plant,
98 sets at a sulfurlc acid plant). 99 percent
r the sets were read with a positive error of
>ss than 7.5 percent opacity; 95 percent were
ead with a positive error ofless than 5 per-
ent opacity.
The positive observational error associated
rtth an average of twenty-five readings Is
therefore established. The accuracy of- the
aethod must be taken Into account-when
letennlning possible violations of appll-
able opacity standards.
'For a sst, positive error=average opacity
letermined by observers' 35 observations—
.verage opacity determined from transmla-
ometer's 25 recordings.
1. Principle and applicability!
l.t Principle. The opacity of emissions
from stationary sources is determined vis-
ually by a qualified observer. -
1.2 Applicability. This method Is appli-
cable for the determination of the opacity
of emissions from stationary sources pur-
suant to |60.11(b) and for qualifying ob-
servers for visually determining opacity of
emissions.
2. Procedures. The observer qualified in
accordance with paragraph 8 of this method
shall use the following procedures for vis-
ually determining the opacity of emissions:
3.1 Position,. The qualified observer shall.
stand at a distance sufficient to provide a
clear view of the emissions with the sun
oriented In the 140* sector to bis back. Con-
sistent with maintaining tba above require-
ment, the observer shall, as much as possible.
make his observations from a position such
that bis Una of vision is approximately
perpendicular to the plume direction., and
when observing opacity of emissions from
rectangular outlets (e.g. roof monitors, open
Doghouses, nonclrcular stacks), approxi-
mately perpendicular to the longer axis of
the outlet. The observer's line of sight should
not Include more than one plume at a time
when multiple, stacka are involved, and in
any case the observer should make his ob-
servations with his line of sight perpendicu-
lar to the longer axis of such a set of multi-
ple stocks (e.g. stub stacks on baghouses).
2.2 Field records. The observer shall re-
cord the name of the plant, emission loca-
tion, type facility, observer** name and
affiliation, and the date on a field date sheet
(Figure 9-1). The time, estimated distance
to the «i^i««i«»t location, approximate wind
direction, estimated wind speed, description
of the sky condition (presence and color of
clouds), and plume background are recorded
on a field data sheet at the time opacity read-
ings are initiated and completed.
2.3 Observations. Opacity observations
shall bo made at the point of greatest opacity
In that 'portion of the plume where con-
densed water vapor is not present. The ob-
server, shall not look continuously at the
plume, but instead shall observe the plume
mome'ntarUy at 15-*econd intervals.
2.3.1 Attached steam plumes. When con-
densed water vapor is present within the
plume as it emerges from the emission out-
let, opacity observations shall be made be-
yond the point in the plume at which con-
densed water vapor is no longer visible. The
observer shall record the approximate dls-
tanca from the emission outlet to the point
In the plume at which the observations are
made.
2 35 Detached steam plume. 'When water
vapor in the plume condenses and becomes
visible at a distinct distance from the emis-
sion outlet, the opacity of emissions should
be evaluated at the emission outlet prior to
the condensation of water vapor and the for-
mation of the steam plume. •
2.4 Recording observations. Opacity ob-
servations shall be recorded to the* nearest S
percent at 15-second intervals on an ob-
servational record sheet. (See Figure 9-3 for
an example.) A minimum of 34 observations
shall be recorded. Each momentary observa-
tion recorded shall bo deemed to represent
the average opacity of emissions for s 15-
second period.
2.S Data Reduction. Opacity shall be de-
termined as an average of 24 consecutive
observations recorded at 15-second intervals.
Divide the observations recorded on the rec-
ord sheet Into sets of 24 consecutive obser-
vations. A set is composed of any 24 con-
secutive observations. Sets need not be con-
secutive In time and In no case shall two
sets overlap. For each set of 24 observations,
calculate the average by summing the opacity
of tbe 24 observations and dividing this sum.
by^4. If an applicable standard specifies an
averaging time requiring more tb»^ 24 ob-
servations, calculate the average for all ob-
servations made during the specified time
period. Record the average opacity on a record
sheet. (See Figure 9-1 for an example.)
3. Qualifications and testing.
3.1 Certification requirements. To receive
certification as a qualified observer, a can-
didate must be tested and demonstrate the
ability to assign opacity readings in 5 percent
increments to 35 different black plume* and
3S different whit* plumes, with SA •nor
not to exceed IB percent opacity on any one
reading and an average error not to exceed
7.5 percent opacity in each category. Candi-
dates shall be tested according to the pro-
cedures described In paragraph 8.3, Smoke
generators, used pursuant to paragraph 3.2
shall be equipped with a smoke meter which
meets the requirements of paragraph 3.3.
The certification shall be valid for a period
of 6 months, at which time the qualification
procedure must be repeated by any observer
in order to retain certification. _ :
• 3.2 Certification procedure. The certifica-
tion test consists of showing the candidate a
complete run of 60 plumes—25 Mack plumes
and 25 white plumes—generated by a smoke
generator. Plumes within each set of 25 blade
and 25 white runs shall be presented In ran-
dom order. Tbe candidate assigns an opacity
value to each plume and records his obser-
vation on a suitable form. At tbe completion
of each run of CO readings, the score of the
candidate is determined. If a candidate falls
to qualify, the complete run of 50 readings
must be repeated In any retest. The smoke
teat may be administered as part of a smoke
school or training program, and may be pre-
ceded by training or familiarization runs of
the smoke generator during which candidates
are shown black and white plumes of known
opacity.
. 33 Smoke generator specifications. Any
smoke generator used for the purposes of
paragraph 3.2 shall be equipped with u smoke
meter Installed to measure opacity across
the diameter of the smoke generator stack.
The smoke meter output shall display In-
stack opacity based upon a pathlength equal
to tbe atock exit diameter, on a full 0 to 100
percent chart recorder scale. The smoke-
meter optical design and performance shall
meet the- specifications shown In Table 9-1.
The smoke meter shall be calibrated as pre-
scribed in paragraph 3 J.I prior to the con-
duct of each smoke reading test. At the
completion of each test, the zero and span
drift shall be checked and if the drift ex-
ceeds 2:1 percent opacity, the condition cv»»n
be corrected prior to conducting any subse-
quent test runs. The smoke meter shall bo
demonstrated, at the time of installation, to
meet the specifications listed in Table 9-1.
This demonstration shall bo repeated fol-
lowing any subsequent repair or replacement
of the photocell or associated electronic cir-
cuitry Including the chart recorder or output
meter, or every 8 months, whichever occur*
flrmt.
3.3.1 Calibration. Tbe ' omoke meter 1*
calibrated after allowing a minimum of 80
minutes warmup by alternately producing
simulated opacity of 0 percent and 100 per-
cent. When stable response at 0 percent or
100 percent is noted, the smoke meter is ad-
justed to produce an output of 0 percent or
100 percent, as appropriate. This calibration
shall be repeated until stable 0 percent and
100 percent readings are produced without
adjustment. Simulated 0 percent and 10O
percent opacity values may be produced by
alternately switching the power to the light
source on and off vhile the smoke generator
.Is-not producing smoko.
-------
TABU •— I— «MOXK VETO DCSXGK AND
SPECIFICATIONS
Incandescent lamp
operated at nominal
rated voltage.
Fhotoplo (daylight
spectral response of
the Human eye—
. reference 4.3).
15* «^-»imnm total
angle.
15* ™
-------
Appendix C
Blank Data Forms
Field Observation Checklist
Process and Control System Evaluation Form
Opacity Observation Record
-------
PAGE OF
FIELD OBSERVATION CHECKLIST
GENERAL/ADMINISTRATIVE
PLANT NAME
PLANT ADDRESS
SOURCE TO BE TESTED
PLANT CONTACT
OBSERVERS
REVIEWED TEST PROTOCOL?
AFFILIATION
COMMENTS
DATE
PHONE
REVIEWED PRETEST MEETING NOTES?
COMMENTS
REVIEWED CORRESPONDENCE?
COMMENTS
TEST TEAM COMPANY NAME
SUPERVISOR'S NAME
OTHER MEMBERS
ADDRESS
TITLE
PHONE
-------
PAGE OF
GENERAL/SAMPLING SITE
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 SECTIONAL VIEW SHOWING DIMENSIONS AND PORT LOCATIONS.
-------
PAGE OF
GENERAL/SAMPLING SYSTEM
SAMPLING METHOD (e.g., EPA 5)
SAMPLING TRAIN SCHEMATIC DRAWING:
MODIFICATIONS TO STANDARD METHOD
PUMP TYPE: FIBERVANE WITH IN-LINE OILER CARBON VANE DIAPHRAGM
PROBE LINER MATERIAL HEATED? ENTIRE LENGTH?
TYPE "S" PITOT TUBE? OTHER
PITOT TUBE CONNECTED TO: INCLINED MANOMETER OR MAGNEHELIC GAUGE _
RANGE APPROX. SCALE LENGTH DIVISIONS
ORIFICE METER CONNECTED TO: INCLINED MANOMETER OR MAGNEHELIC GAUGE
RANGE APPROX. SCALE LENGTH DIVISIONS
METER BOX BRAND SAMPLE BOX BRAND
RECENT CALIBRATION OF ORIFICE METER-DRY GAS METER? PITOT TUBES?
NOZZLES THERMOMETERS OR THERMOCOUPLES? MAGNEHELIC GAUGES?
NUMBER OF SAMPLING POINTS/TRAVERSE FROM FED. REG. NUMBER TO BE USED _
LENGTH OF SAMPLING TIME/POINT DESIRED TIME TO BE USED
-------
PAGE OF
TRAIN ASSEMBLY/FINAL PREPARATIONS (USE ONE SHEET PER RUN IF NECESSARY) RUN #
FILTER HOLDER CLEAN BEFORE TEST? FILTER HOLDER ASSEMBLED CORRECTLY?
FILTER MEDIA TYPE FILTER CLEARLY IDENTIFIED? FILTER INTACT?
PROBE LINER CLEAN BEFORE TEST? NOZZLE CLEAN? NOZZLE UNDAMAGED?
IMPINGERS CLEAN BEFORE TEST? IMPINGERS CHARGED CORRECTLY?
BALL JOINTS OR SCREW JOINTS? GREASE USED? KIND OF GREASE
PITOT TUBE TIP UNDAMAGED? PITOT LINES CHECKED FOR LEAKS? PLUGGING?
METER BOX LEVELED? PITOT MANOMETER ZEROED? ORIFICE MANOMETER ZEROED?
PROBE MARKINGS CORRECT? PROBE HOT ALONG ENTIRE LENGTH?
FILTER COMPARTMENT HOT? TEMPERATURE INFORMATION AVAILABLE?
IMPINGERS ICED DOWN? THERMOMETER READING PROPERLY?
BAROMETRIC PRESSURE MEASURED? IF NOT, WHAT IS SOURCE OF DATA
AHfl FROM MOST RECENT CALIBRATION AHn FROM CHECK AGAINST DRY GAS-METER
(d (d
NOMOGRAPH CHECK:
IF AH@ = 1.80, TM =100° F, % HgO - 10%, Ps/Pm =1.00, C = (0.95)
IF C = 0.95, TS = 200° F^ DN = 0.375, Ap REFERENCE = _ (0.118)
ALIGN Ap = 1.0 WITH AH = 10; @ Ap = 0.01, AH = (0.1)
FOR NOMOGRAPH SET-UP:
ESTIMATED METER TEMPERATURE : °F ESTIMATED VALUE OF Ps/Pm
ESTIMATED MOISTURE CONTENT % HOW ESTIMATED?
C FACTOR ESTIMATED STACK TEMPERATURE ° F DESIRED NOZZLE, DIAMETER
STACK THERMOMETER CHECKED AGAINST AMBIENT TEMPERATURE? '.
LEAK TEST PERFORMED BEFORE START OF SAMPLING? • RATE CFM @ IN. Hg.
-------
PAGE OF
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 STACK?
IS PROBE MOVED TO EACH POINT AT THE PROPER TIME?
IS PROBE MARKING SYSTEM ADEQUATE TO PROPERLY LOCATE EACH POINT?
ARE NOZZLE AND PITOT TUBE KEPT PARALLEL TO STACK WALL AT EACH POINT?
IF PROBE IS DISCONNECTED FROM FILTER HOLDER WITH PROBE IN THE STACK ON A
NEGATIVE PRESSURE SOURCE, HOW IS PARTICULATE MATTER IN THE PROBE PREVENTED
FROM BEING SUCKED BACK INTO THE STACK?
IF FILTERS ARE CHANGED DURING A RUN, WAS ANY PARTICULATE LOST?
METERBOX OPERATION:
IS DATA RECORDED IN A PERMANENT MANNER? ARE DATA SHEETS COMPLETE?
AVERAGE TIME TO REACH ISOKINETIC RATE AT EACH POINT
IS NOMOGRAPH SETTING CHANGED WHEN STACK TEMPERATURE CHANGES SIGNIFICANTLY? _
ARE VELOCITY PRESSURES Up) READ AND RECORDED ACCURATELY?
LEAK TEST PERFORMED AT COMPLETION OF RUN cfm @ IN Hg.
PROBE, FILTER HOLDER, IMPINGERS SEALED ADEQUATELY AFTER TEST?
GENERAL COMMENT ON SAMPLING TECHNIQUES
IF ORSAT ANALYSIS IS DONE, WAS IT: FROM STACK FROM INTEGRATED BAG
WAS BAG SYSTEM LEAK TESTED? WAS ORSAT LEAK TESTED? CHECK AGAINST AIR?
IF DATA SHEETS CANNOT BE COPIED, RECORD: APPROXIMATE STACK TEMPERATURE ° F
NOZZLE DIA. IN. VOLUME METERED ACF
FIRST 8 Ap READINGS .
-------
PAGE OF
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 PARTICULATE
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
-------
PROCESS AND CONTROL SYSTEM EVALUATION FORM
Company Name
Address
Company Official:_
Plant Identification_
Location:
I. Process Data
Rated Capacity of Dryer
Maximum Production Rate
Actual Production Rate
Batch Size
Process Weight Rate
Cold Aggregate Feed Rate
Atons\ at
"V ** I
f tons\ Normal Production Rate
1 hrj
% aggregate moisture content.
/ tons
(Ibs)
I tons \
hr j
/ tons\
\hr/
/ tons \
•(jhr-J
Type Mixture
Mixture Composition
Aggregate Sizes
-)
%Asphalt
Aggregate Feeds percent moisture
sieve analysis, % material retained on:
No. 8 % No. 32 % No. 100
% No. 200
percentage fines - material passing No. 200-mesh sieve
Burner Rating
(Btu/hr)
Fuel Consumption
(gal/hr)
Type of fuel_
(ft3/hr)
(ftton)
(gal/ton)
Hot Aggregate Temperature
Excess Air at Dryer Exit
Damper Position, %open
°F. Exhaust Gas Temperature
>F.
-------
II. Control System Data:
schematic diagram (exhaust system)
Baghouse: Static pressure drop, Ap (in. HO)
cleaning cycle timer setting
cleaning cycle pressure setting
Effective Filter Area__ Type of cloth
Inspection of Baghouse Interior-comments
Wet collection devices:
Venturi Scrubber- s
throat opening dimensions
Venturi Scrubber- static pressure drop,Ap (in. HO)
2
throat opening area (ft )
Low Energy Scrubber- oriface opening
water level
Water Flow Rate: Weir Formula
Type of meter cross-sectional area of flow
horizontal distance x (ft)
Water Pump, horsepower , rated capacity rpm
Water-flow rate (gal/min)
Water Pressure: main scrubber supply line (psig)
spray system supply lines (psig)
-------
Dilution Measurements - (note location on system diagram)
%co
location time . 2
1
2
3
4
System Air Flow:
Cyclone- static pressure drop- Ap (in. HO)
Fan Rating: horsepower , capacity at rpm
Measured Fan Speed rpm
Fan-static pressure rise, Ap_ (in. HO)
Determined Opacity
-------
Date
Observer
Checked by
Start Time
Opacity Observation Record
__________ Source Location.
i Address ———
Observation Point
Stack-distance from Ht.
Wind-speed • Direct..
Sky Condition
Type of Installation
Fuel
Observ. Ended
Smoke Density Tabulation
Units No. 0
Units No. 5
Units No* 10
Units No. 15
Units No. 20
Units No
Units No
Units No
Units No
Units No
Units No
Units No
Units No
Units No
Units No
Units No
Units No
Units No
Units No
Units No
25_
30_
35_
40_
45_
50_
55
60
65
70_
75_
80
85
90
95
Units No. 100
Total Units
2quiv. Opacity- ~
REMARKS:
-*-
M^X
0
i
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
0
15
^
30
45
^
30
31
• 32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
0
15
30
V -
•
45
-------
Appendix D
ISOK1NETIC PARTICIPATE SAMPLING IN
NON-PARALLEL FLOW SYSTEMS - CYCLONIC FLOW
JAMES W, PEELER
ENTROPY ENVIRONMENTALISTS, INC,
-------
ISOKINETIC PARTICULATE SAMPLING IN NON-PARALLEL
FLOW SYSTEMS- CYCLONIC FLOW
In most stationary sources, the direction of gas flow is
essentially parallel to the stack axis. Examples of non-parallel
flow systems are flow immediately following a bend or turn in the
ductwork, flow in a convergent or divergent section, and cyclonic
(tangential) flow. Cyclonic flow most often occurs after inertial
demisters following wet scrubbers, in stacks with tangential in-
lets, and after axial fans. Method 1—Sample and Velocity Traverses,
and Method 2—Determination of Stack Gas Velocity and Volumetric
Flow Rate, are not applicable to stacks; with cyclonic flow. Method
1 (2.4), gives explicit instructions for determining when unac-
ceptable flow .conditions exist. In short, the angle (between the
pitot orientation and the plane perpendicular to the stack axis)
required to produce a null reading is measured for each sampling
point. If the average of the absolute.values of the angles is
greater than.10°, unacceptable flow conditions exist.
In many cases, particulate sampling is required even though
the appropriate reference methods are not applicable due to non-
parallel flow. This situation occurs more frequently at existing
sources than at new sources, since sources subject to NSPS are
required to provide sampling locations which permit sampling
according to the appropriate reference methods. There are
three possible alternatives when unacceptable flow conditions
exist:
(1) modify the sampling methodology to obtain accurate results
-------
(2) use standard or alternate methodology which gives results
biased high (in the agency's favor), or (3) modify the source
to permit standard sampling procedures to be used. This paper
discusses three sampling procedures which have been commonly
proposed. Also, source modifications which can be employed are
described. Current studies on tangential flow may provide better
solutions in the future.
BACKGROUND INFORMATION
In order to determine the biases of various sampling tech-
niques in non-parallel flow systems, it is necessary to under-
stand the requirements of proportional sampling and the errors
associated with pitdt tube measurements.
Proportional Sampling - Source sampling is conducted to
determine the concentration of a particular pollutant in an
effluent stream. The concentration of component Z which is re-
presentative of the effluent is, (1)
; _ volume-of component Z _ CZ * V^/sec) x A(ft2) x 9(sec)
Z total volume of effluent V(£t/sec) x A(£t2) x e(sec)
C_ = I, if component Z is a gas .
C7 = Ibs/ft , if component Z is particulate
i-t
For a steady state source with spatial variations in concen-
tration and velocity, Equation (1) can be expressed as,
C - 4 CZVdA (2)
\ VdA
-------
Evaluation of Equation (2) requires knowledge of concentration
and velocity as functions of location across the stack cross
section. In practice, the integrals in Equation (2) are
approximated by sampling at a finite number of points,
?Ci ViAJ9i
CZ~~ zVi Ai ei C3)
In the application of standard EPA methods, equal areas are
sampled for equal times. Equation (3) becomes,
*CiVi
cz = STT- (4)
z EVT-
It is hot feasible to determine the concentration (C-) .,at 'each
sampling point. However, the quantity ['£C.V.']> can be .evaluated
i x 1
by collecting a single integrated sample where the sampling rate
is weighed-proportionally to the stack velocity at each sampling
point. This procedure of sampling at a rate which is related-to
the stack velocity by a constant is referred to as proportional
sampling. In the preceding discussion it has been assumed that
the velocity of the effluent stream is parallel to the stack
axis. In non-parallel flow systems, the sampling rate should
be weighted proportionally to the component of the velocity
parallel to the stack axis.
When sampling for particulates it is necessary to sample
isokinetically to obtain a representative sample. For sources
where the velocity is parallel to the stack axis, isokinetic
sampling is a special case of proportional sampling where the con-
stant relating the sampling velocity ±x> the stack velocity is 1.
-------
Thus, in parallel flow systems, isokinetic sampling auto-
matically satisfied proportional sampling requirements. For
non-parallel flow systems, isokinetic sampling conditions must
be based on the velocity vector, however, proportional sampling
conditions must be based on the component of velocity parallel
to the stack axis. This creates considerable difficulty in
sampling non-parallel flow systems. .
Pitot Tube Errors - Pitot tube errors arise when the pitot
tube is not oreinted correctly with respect to the gas stream
velocity vector. Two types of pitot tube misalignment are shown
in Figure.4-4. Figures 4-5 8 4-6 show the % error in the velocity
vector measurement as a function of yaw and pitch angles for
a S-Type pitoti When the S-Type pitot is part of a probe
assembly, the % error has even greater dependence on pitch and
yaw angles.
A
Yaw Angle Misalignment Pitch Angle Misalignment
Figure 4-4•. Types of Pitot "Tube Misalignment
-------
Figure 4-5 Velocity Errors from Yaw Angle Misalignment
Figure 4-6 Velocity Errors from Pitch Angle Misalignment
-------
SAMPLING TECHNIQUES FOR NON-PARALLEL FLOW SYSTEMS
When attempting to sample a source with non-parallel flow,
several problems are encountered; (1) velocity measurements
are subject to pitot tube errors, (2) volumetric flow rate
determinations are difficult, (3) problems arise relating to
the alignment between the sample nozzle and flow stream, (4)
proportional sampling conditions are difficult to maintain; and
(5) the inertial properties of the dust particles introduce
biases of unknown magnitude. These problems are discussed as
they effect three sampling techniques.
Before discussing individual sampling techniques, a bias
which is common to all sampling methods for non-parallel flow
systems should be considered. All of the approaches which will
be described assume that a sample which is collected isokineti-
cally and weighted proportionally to the axial velocity will
accurately reflect the particulate concentration in the effluent
stream. The methods for determining isokinetic and proportional
sampling conditions are based on measurements of gas velocity.
It should be noted that non-parallel flow systems are created by
inertial forces acting on the gas stream as the effluent moves
through the stack or ductwork system. Since dust particles are
subject to much greater inertial affects than are gas molecules,
the actual velocities of the particles and the gas stream will
not be the same under cyclonic or other non-parallel flow con-
ditions. In almost all cases, the greater inertial affects on
particles will create larger angles between the particle velocities
and the stack axis than between the gas velocity and the stack
-------
axis. This introduces a low bias of unknown magnitude in the
measured concentration due to misalignment of the sampling
nozzle with respect to the particle velocities. This bias in-
creases as the particle size increases.
Criteria for determining the minimum number of sampling
points and for locating the sampling points in non-parallel
flow systems must be developed since Method 1 is not applicable
in these cases. It is recommended that 48 sampling points (the
maximum specified by Method 1) be used until applicable criteria
can be developed. All of the sampling techniques which will be
presented ass.ume that sampling -is conducted at points repre-
senting equal are.as .of the stack, cross-sec.tional area. The pro-
cedures in Method (!•-for locating sampling points should be em-
ployed.
Blind Man's Approach--The blind man's approach is so named since
the standard test methods are applied and the non-parallel flow
situation is simply ignored. This procedure is subject to
multiple biasing affects.
Since the nozzle is not aligned with the direction of the
flow, the apparent or effective area of the nozzle opening is
reduced. If the angle between the flow direction and the per-
pendicular to the nozzle opening is <)> , then the area of the
nozzle opening perpendicular to the flow stream is reduced by
cos . (Figure 4-7).
-------
J O
actual area A =TT[ •=• 3
effective area = A cos
Figure 4-7. Reduction of effective area of nozzle not aligned
with direction of flow.
-------
In this approach, the sampler has no knowledge of the angle 4>
and therefore the sampling rate will be overisokinetic by an
amount directly proportional to cos .. .
Figures 4-5 and 4-5 show that the pitot tube gives incorrect
readings when not aligned with the flow. For all yaw angles
where -40° < 0 < 40° and for all positive pitch angles the
pitot gives higher than real readings. Thus for three out of
four cases of misalignment the pitot gives high readings which
creates overisokinetic sampling conditions. It should be noted
that the pitot readings will be further influenced when the an-
gle of the flow is such that the pitot is effectively on the down-
stream side of the sampling nozzle. In this situation the noz-
zle disturbs the flow stream and introduces additional velocity
measurement errors.
The effects of the reduced effective nozzle opening, and,
in most cases, the effects of the pitot error, contribute to
overisokinetic sampling. Overisokinetic sampling biases the
concentration measurement low. The degree of the bias increases
as the particle size increases.
In the blind man's approach, the sampling rate is weighted
proportionally to the magnitude of the velocity vector. In
order to meet the constraint of proportional sampling, the
sampling rate should be weighted proportionally to the component
of the velocity vector parallel to the stack axis. Therefore, if
the angle between the velocity vector and the stack axis varies
across the cross section of the.stack, then proportional sampling
conditions are not maintained. The bias which results from
-------
non-proportional sampling increases as the variations in velocity
and concentration across the stack increase. The direction of the
bias is not easily determined.
If sampling is conducted to determine compliance with a mass
emission rate standard, (Ibs/hr), the total volumetric flow rate
must be determined. Misalignment to the pitot with the flow re-
sults in errors in determining the magnitude of the velocity vec-
tor. A second error in determining the volumetric flow rate arises
because the velocity vector is not parallel to the axis of the
stack. The axial velocity vector component is equal to the velocity
vector times the cos ^ , (where is the angle between the velocity
vector and the stack axis). The errors in determining the axial
velocity component due to pitot misalignment error, and due to ve-
locity direction error can be combined, and are shown in Figures
4-8 and 4-9. From these figures it is apparent that the axial velocity
and thus the volumetric flow rate are overestimated. The degree
of the bias cannot be estimated since, in the blind man's approach,
the sampler has no knowledge of the angle between the velocity
and the stack axis.
The mass emission rate is the product of the concentration
measur-ed by the sampling train and the total volumetric flow rate.
The concentration is biased low and the volumetric flow rate
is biased high. The two errors tend to offset each other; however,
it is not possible to determine the net affect due to the unknown
extent of the biases. In addition, the magnitude and direction of
the bias due to non-proportional sampling is unknown.
In some stacks, negative velocities are encountered at
particular sampling points. When negative velocities are
-------
Figure 4-8. Axial Velocity Component Error due to Yaw Angle Misalignment
Figure 4-9. Axial Velocity Component Error due to Pitch Angle Misalignment
-------
encountered, no sampling should be conducted. This biases the
concentration determination high if the negative flow region
contains any particulate material. When determining the vol-
umetric flow rate for use in calculating a mass emission rate,
the negative pitot reading(s) should be used to calculate the
quantity of negative volumetric flow which should then be sub-
tracted from the positive volumetric flow. It should be remem-
bered that negative velocity measurements are subject to similar
errors as positive velocity measurements. Neglecting the pitot
errors, the mass emission rate will be biased high due to the
high bias in the concentration measurement created by negative
flow.
Alignment Approach--The alignment approach invloves determina-
tion of the direction of flow at each sampling point (by means
of three dimensional pitot sensor or similar device). The
sampling nozzle and pitot are then aligned with the flow direction
at each sampling point.
For standard Method 5 particulate sampling equipment, it
is easy to rotate the sampling probe for different yaw angles.
However, it is not possible to align the sampling nozzle and
pitot for different pitch angles. Therefore, the alignment
method is not applicable to sources where pitch angle misalign-
ment exists. Figures 4-10 and 4-11 show pitch and yaw angles for
a typical stack with cyclonic flow.
In the alignment method, the sampling rate must be based on
the magnitude of the velocity vector at each sampling point to
maintain isokinetic sampling conditions. If the yaw angle varies
-------
Stack Wall
10°-
10° .
20°_
30° -
Center of Stack
Stack Wall
Figure 4-10. Typical Pitch Angle Profile in Stack with Cyclonic Flow. Current
Data near Walls and at Center is Unreliable.
Stack Wall
40e
50° .
60C
70°
80° -
90°
Center of Stack
Stack Wall
Figure 4-11.
Typical Yaw Angle Profile,in ;Stack with Cyclonic Flow. Current
Data near Walls and at Center' is Unreliable.
-------
across the stack cross section, then the sampling velocity is
not weighted proportionally to the axial component of the
velocity vector. In this situation, proportional sampling
requirements can be satisfied by adjusting the sampling time
for each sampling point such that the volume of sample collected
is related by a constant to the axial velocity component at each
sampling point. This can be accomplished by weighting the
sampling time at each point by cos<|> (where is the angle between
the velocity vector and the stack axis):
92 = el cos* (S)
6, = nominal sampling time per point
62 = actual sampling time at a point
= misalignment angle at a point
The sampling team should be careful in selecting the nominal
sampling time per point to ensure collection of the minimum
required sample volume since application of Equation 5 will re-
duce the actual sampling time.
In sampling to determine compliance with a mass emission
rate standard the volumetric flow rate must be determined. Since
the angle of the velocity vector (with respect to the stack
axis) must be determined to apply the alignment approach, the
axial volumetric flow rate can be calculated as:
N ._
j:z (\£P~ coscj^)
'— (6)
-------
where: Q = stack volumetric flow rate (ft /sec)
actual conditions
K = 85.48
C = pitot tube coefficient
2
A = stack cross-sectional area (ft )
T_ = average stack temperature (°R)
P = absolute stack pressure (in. Hg)
M = molecular weight of stack gas, wet
s (Ib/lb-mole)
A = pitot reading' (in H^O)
<|> = angle between velocity vector and stack axis
N = number of sampling points
No additional biases are introduced-when calculating the volu-
metric flow rate if the angles . are accurately known.
No sampling should be conducted at sampling points where
negative velocities are observed. There "'is no way to assign
a negative value to the quantity C.V. when the velocity Is
negative since the sampling train obtains an integrated sample,
[E C-V-]. The fact that negative flows are not sampled biases
thie concentration measurement high if the negative flows contain
any particulate matter. When determining a mass emission rate,
the negative volumetric flow rate should be calculated based on
the negative axial velocity component.- The net volumetric •
flow rate, (positive volumetric flow rate minus negative volu-
metric flow rate), must be used to calculate the mass emission
rate. Where negative velocities are encountered, the mass
emission rate will be biased high due to the bias in the
concentration measurement.
-------
Compensation Approach - The compensation approach requires
determination of the direction of flow at each sampling point,
(by means of a three dimensional pitot sensor or similar device),
and measurement of the velocity vector at each sampling point.
In the compensation approach, the sampling nozzle is aligned with
the stack axis as in the blind man's approach. This method is
applicable to sources with both pitch and yaw angle misalignment
if a separate pitot and sampling probe are used.
The nozzle is not aligned with the flow direction; therefore
the effective nozzle area is reduced by cos* , Figure 4-12. In
the compensation approach, the angle $ is known and the sampling
rate is reduced by cos to maintain isokinetic sampling conditions.
The use of the nozzle area correction requires that the isokinetic
sampling rate is proportional to both the velocity vector V and
cos<|> . Since the axial velocity component V is Vcos<|> , the
ct
nozzle area correction also weights the sampling rate proportion-
ally to the axial velocity. Therefore the requirements of
proportional sampling are satisfied.
The compensation approach is subject to biases when the
angle between the nozzle and the flow stream becomes sufficient-
ly large. For very large angles of misalignment, the flow
around the nozzle will create aerodynamic interferences with the
isokinetic sampling. In general, these interferences will bias
the concentration measurement low. The degree of the bias will
increase as the velocity increases and as the angle of misalign-
ment increases. Further study is required to determine at what
angle these affects become significant and the extent of the
biases on the sampling results.
-------
actual nozzle opening
area, A
effective area, EA
EA = A cos
Figure 4-12. Compensation Approach
-------
When sampling to determine a mass emission rate, the
volumetric flow rate should be determined as:
N
as in the alignment approach. No additional biases are intro-
duced in calculating the volumetric flow rate if the angles
are determined accurately.
As in the alignment approach, no sampling should be con-
ducted at sampling points where negative velocities are ob-
served. Again, this biases the concentration high if the
negative flow contains particulate matter. To calculate the
net volumetric flow rate where negative flows are encountered,
Equation 6 can be used by adding a negative sign to cos
where is negative, or the negative volumetric flow can be
subtracted from the positive volumetric flow. Where negative
flows are encountered the mass emission rate will be biased
high due to the high bias in the measured concentration.
SOURCE MODIFICATIONS
In some non-parallel flow situations, modifications to
the source can be made which permit application of the stan-
dard sampling methodology. The simplest source modification is
to move the sampling site to an alternative location and there-
by avoid the problem altogether. This option is generally not
available since anticipated non-parallel flow conditions should
have been a major consideration in the selection of the origi-
-------
nal sampling site. A second modification is to employ
straightening vanes to eliminate the non-parallel flow.
Straightening vanes can be fabricated of almost any material
(depending on the temperature encountered). In most cases, a
single vane or a pair of vanes at- 90°, extending across the
stack are"sufficient to eliminate the flow problem. The
straightening vanes should be at least 1/2 stack diameter in
length, (parallel to axis of stack).
At some sources, particularly at asphalt plants, a stack
with cyclonic flow functions as part of the inertial demister
system for wet scrubbers. Straightening vanes' employed in
this situation would eliminate the stack' s' 'function as-^"'Con-
trol device and thereby greatly increase emissions. In'most
cases, a stack extension equippped with straightening vanes
can be employed (Figure 4-13). Straightening vanes are used
to create a flow disturbance which improves the flow condi-
tions downstream at the sampling site. The flow disturbance
from straightening vanes also propagates upstream to an un-
known extent. It should also be noted that straightening vanes
exert work on the effluent stream which is evidenced by a
pressure drop across the vanes. In most cases, the straighten-
ing vanes will have little affect on the volumetric flow rate
through the system since the pressure drop across the vanes
is small compared to other pressure drops in the effluent
handling system. Ideally, any modifications which are employed
should not affect the flow pattern in stacks which function
as part of the control system. Any affects on the flow pat-
tern in the existing stack will generally reduce the cyclonic
-------
flow and increase the emission rate. Adherence to the follow-
ing criteria will minimize the affects of a stack extension
and straightening vanes.
1. the stack extension should be the same diameter
as the existing stack
2. the straightening vanes should be at least 1/2
stack diameter .downstream from the exit of the
existing stack
3. the extension must be at least 2 1/2 diameters in
length after the straightening vanes.
A second type modification which can be used for stacks with
cyclonic flow is essentially the addition of a tangential
outlet duct (Figure 4-14). Although this type of extension is
more difficult to construct, there:is less affect on the flow
pattern in the existing stack and straightening vanes in the
extension may not be necessary. In some cases, the diameter
of the extension may be smaller than the existing stack which
reduces the actual length of the extension. In any case, the
extension must be at least 2 1/2 diameters in length to
satisfy the minimum requirements of Method 1.
-------
CONCLUSIONS
When particulate sampling is required and where non-
parallel flow conditions are encountered, a decision must
be made to either modify the source to eliminate the un-
acceptable flow situation or apply one of the special
sampling procedures which have been discussed. Source modi-
fications should be employed when feasible since they will
reduce the complexity and difficulty in obtaining a repre-
sentative sample. Modifications to sources where stacks with
cyclonic flow function as part of the control system should
be carefully planned.
Where source modifications can not be employed and special
sampling procedures are to be used, either the alignment
approach or the compensation approach should be used. The
blind man's approach should not be used due to the many
problems which are encountered which result in unknown biases
in the sampling results. The alignment approach is limited
to non-parrallel flow situation where only yaw angle misalign-
ment exists. The compensation method can be used in any non-
parallel flow situation, however a low bias in the sampling
results may occur for large angles of misalignment. Both the
alignment appeoach and the compensation approach allow a
particulate sample to be obtained isokinetically and both
approaches satisfy the requirements of proportionally weighting
the sampling relative to the stack axial volumetric flow rate.
Application of either the alignment or compensation approach
will require considerably more time and effort to obtain valid
sampling results than is encountered in the application of
standard particulate sampling procedures.
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>l/2d
>2d
>l/2d
>l/2d
TOP VIEW
\
Figure 4-13. Stack
Extension With Straightening
Vanes
Figure 4-14.
Temporary Tangential
Outlet
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