EPA 340/1-76-003
MARCH 1976
Stationary Source Enforcement Series
INSPECTION MANUAL FOR ENFORCEMENT OF
NEW SOURCE PERFORMANCE STANDARDS
ASPHALT CONCRETE PLANTS
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Enforcement
Office of General Enforcement
Washington, D.C. 20460
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INSPECTION MANUAL FOR ENFORCEMENT
OF NEW SOURCE PERFORMANCE STANDARDS:
ASPHALT CONCRETE PLANTS
Contract No 68-02-1356, Task 2
EPA Project Officer: Mark Antell
Prepared for
U.S. Environmental Protection Agency
Division of Stationary Source Enforcement
Washington, D.C.
January 1976
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This report was furnished to the U.S. Environmental Pro-
tection Agency by JACA Corp., Fort Washington, Pennsylvania, in
fulfillment of Contract No. 68-02-1356, Task No. 2. The con-
tents of this report are reproduced herein as deceived from the
contractor. The opinions, findings, and conclusions expressed
are those of the author and not necessarily those of the Envir-
onmental Protection Agency.
11
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ACKNOWLEDGMENTS
The assistance obtained from many individuals from
EPA in the preparation of this manual is gratefully acknow-
ledged. JACA Corp. wishes to especially thank Mr. Neil Berg
of EPA for the use of a preliminary draft of this manual, Mr.
Mark Antell of DSSE for his supervision and coordination with
the various divisions within the agency, Mr. Kenneth Durkee
and Ms. Jan Meyer of EPA for their technical review of the
first draft, Mr. John Rasnic of EPA region III for his com-
ments on the practical enforcement aspects of NSPS. We al-
so appreciate the advice of industry personnel including Mr.
Edward Siodlowski of Pennsylvania Asphalt Paving Association,
Mr. S. Wayne Simmons of Eastern Industries, Inc., and Mr. John
DiRenzo of Highway Materials, Inc., for their review of mater-
ial on industry, process, and raw materials in the draft.
111
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TABLE OF CONTENTS
SECTION PAGE
ACKNOWLEDGMENTS iii
LIST OF FIGURES, TABLES, AND FORMS vii
1 INTRODUCTION 1
2 REGULATIONS 3
2.1 Authority for Promulgation of Standards of
Performance for New or Modified Sources 3
2.2 Standards of Performance for New or Modi-
fied Asphalt Concrete Plants 3
2.3 Applicability 4
2.4 Performance Test Requirements 4
2.5 State Regulations 5
2.6 Emission of Hazardous Air Pollutants 5
3 THE ASPHALT INDUSTRY 7
4 PROCESS DESCRIPTION 11
4.1 Batch Plant 11
4.2 Continuous Plant 12
4.3 Cold Patch 15
4.4 Automation 15
5 RAW MATERIALS 21
5.1 Aggregate 21
5.2 Asbestos 21
5.3 Asphalt Cement 22
5.4 Cut Back Asphalt 22
5.5 Fuel 22
v
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TABLE OF CONTENTS (Continued
SECTION PAGE
6 EMISSIONS 23
6.1 Sulfur Compounds 23
6.2 Odors 24
6.3 Hydrocarbons 24
6.4 Particulates 24
7 CONTROL OF PARTICULATE EMISSIONS 29
7.1 Primary Collectors 29
7.2 Secondary Collectors 33
8 INSPECTIONS 43
8.1 General Inspection Background 43
8.2 Setting Up Visits 43
8.3 Pre-inspection Preparation - Data 45
8.4 Pre-inspection Preparation - Equipment 45
8.5 Initial Procedures for Inspection 46
8.6 Performance Tests Monitoring 47
8.6.1 System, Production and Control
Device Parameters 47
8.6.2 Observation of a Performance
Test 59
8.7 Field Inspections 61
8.7.1 Plant Inspections 61
8.7.2 Control Device Inspection 67
8.7.3 Scavenger Systems 69
8.7.4 Materials Handling Systems 69
8.8 Startup, Shutdown, Malfunction 70
9 POST-INSPECTION ACTION 79
APPENDIX Standards of Performance for New or
Modified Asphalt Concrete Plants
(40 CFR 60)
VI
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LIST OF FIGURES, TABLES, AND FORMS
Figure Page
4-1 Asphalt Batch Mix Plant - An Exploded View 13
4-2 An Asphalt Batch Plant 16
4-3 Diagram of an Asphalt Batch Plant 17
4-4 Asphalt Continuous Mix Plant - An Exploded View 19
7-1 Emissions Route Through Typical Control System 30
7-2 Typical Cold Feed Gradation and Primary Dust
Collector Inlet Gradation 31
7-3 Venturi Scrubber 34
7-4 Efficiency vs. Size for Typical Venturi 36
7-5 Determination of System Pressure Drop 49
8-2 Determination of Pressure Drop Across Collector 57
Table
6-1 Table of Emissions and Sources 24
6-2 Dust Discharge From Asphalt Batch Plants 27
7-1 Particle Size Distribution Before and After
Primary Collection 32
7-2 Control Device Characteristics 41
Form
8-1 Parametric Evaluation Form 25
8-2 Performance Test Observation Form 62
8-3a Observation Record 64
8-3b Record of Visual Determination of Opacity 65
8-4 Inspection Data Form for Asphalt Concrete Plants 72
VI1
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SECTION 1
INTRODUCTION
Pursuant to Section 111 of the Clean Air Act, (42 USC
§1857 et seq.) the Administrator of the Environmental Protec-
tion Agency must from time to time promulgate standards of
performance for new stationary sources which are considered
to contribute significantly to air pollution. Proposed stan-
dards for new asphalt concrete plants were issued in the Fed-
eral Register of June 11, 1973, including standards of perfor-
mance for particulate matter and opacity. Final standards
(40 CFR 60.92) are effective February 28, 1974, and apply to all
sources whose construction or modification commenced after
June 11, 1973. By "commenced" is meant that an owner or
operator has undertaken a continuous program of construction
or modification or that an owner or operator has entered into
a contractual obligation to undertake and complete within a
reasonable time a continuous program of construction or modi-
fication. (40 CFR 60.2)
Applicable law permits EPA to delegate implementa-
tion and enforcement authority on such new or modified sources,
except those owned by the U.S. government, to the states if
the state plan is deemed adequate. Furthermore, a state can
adopt and enforce an emission standard or limitation of its own
provided that it is not less stringent than the federal stan-
dards of performance for new sources.
Regulations for existing plants vary from state to
state, and are frequently written in different terms--either
as a function of process weight, as a percentage of potential
emission, or as particulate concentration. Sometimes provision
is made for one or the other of these requirements to be met
based on which one provides either the larger or smaller al-
lowable emission. Methods of testing also vary: for example
Pennsylvania requires only one test but specifies that con--
densibles be included, whereas federal standards of performance
for new sources require three tests but condensibles are not
included.
Because of differences such as these in regulations
and in permit procedures it is important that coordination
of activities between the state agency and EPA Regional
Office be current and complete. EPA has established guidelines
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for administrative procedures states should adopt to effective-
ly implement and enforce the program for standards of perfor-
mance for new sources.
This manual contains guidelines for the conduct of
field inspections which, together with monitoring of perfor-
mance tests, constitute the basic enforcement tools of the new
source program. Successful operation of the program depends
in large degree on how effective the monitoring and field in-
spection function are conducted.
This manual is essentially divided into two parts.
The first part comprising Sections 1 through 7 present the
federal inspector with background information on the regulations,
industry, process, raw materials, emissions, and control ap-
proaches. The second part covers a step-by-step procedure
for conducting a field inspection and for monitoring a per-
formance test.
Three forms are included in Section 8, and these may
be photo-copied and used by the inspector in monitoring tests
and conducting field inspection. Their use is described in the
text. These forms are:
• Performance Test Observation Form
• Parametric Evaluation Form
• Inspection Data Form for Asphalt Concrete Plants
It is estimated that the function of monitoring a per-
formance test will require the inspector to spend between one
and one and a half days in the field depending on the produc-
tion schedule of the plant and the efficiency of the test crew.
Subsequent field inspection visits should take between two
and four hours after arriving at the site. Neither of these
estimates include preparation time or time after the visits
for any follow through action necessary.
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SECTION 2
REGULATIONS
Air pollution control regulations applicable to the asphalt con-
crete industry are described here.
2.1 Authority for Promulgation of Standard of Performance for
New or Modified Sources
Authority for promulgation of the Standards of Performance
for new sources is contained in Section 111 of the Clean Air Act
(42 U.S.C.§1857 et seq.) which directs the administrator of EPA
to publish and update a list of categories of stationary sources
which are considered significant sources which contribute to the
endangerment of public health or welfare. From this list standards
of performance for new and modified sources within each category
must be promulgated.
2.2 Standards of Performance for New or Modified Asphalt
Concrete Plants
The standards for asphalt concrete plants were proposed
on June 11, 1973, (38 FR 15406) along with several other source
categories. The final version of the standards was published on
March 8, 1974, (39 FR 9308) effective February 28, 1974, for plants
whose construction on modification is undertaken after June 11, 1973.
The following are the final promulgated standards for
asphalt concrete plants (40 CFR 60.92). A reprint of the Standards
of Performance for new sources (40 CFR 60) is contained in the Appendix.
1. No more than 90 mg/dscm (0.04 gr./scf).
2. Less than 20% opacity.
"The concentration standard applies to emission of particulate
matter from the control system, as evidenced by the test methods
required for determining compliance with this standard.'
The opacity standard is to insure that emissions of
particulate matter are properly collected and vented to a control
Background Information for New Source Performance Standards
Volume 3, pg. 9, APTD-1352c.
3
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^
system. This applies to "dryers; systems for screening, handling,
storing, and weighing hot aggregate; systems for loading, transferring
and storing mineral filler; systems for mixing asphalt concrete;
and the loading, transfer, and storage systems associated with
emission control systems." (40 CFR 60.90) Therefore the opacity
regulation covers all of the aforementioned sources and is not
limited to stack emissions. The opacity limit is designed to
insure proper operation and maintenance of process and control
equipment.
2.3 Applicability
In the process of promulgating these standards there was
some debate and misunderstanding as to what constitutes a new or
modified source and therefore subject to the Standards of Per-
formance for new sources.
The latest clarification on applicability was incorporated
in the Standards of Performance for new sources (40 CFR 60.1) which
read: "The provisions of this part apply to the owner or operator
of any stationary source which contains an affected facility the
construction or modification of which is commenced after the date
of publication in this part of any standard (or, if earlier,
the date of publication of any proposed standard) applicable to
such facility." For the asphalt concrete industry the standards
were first proposed on June 11, 1973, (39 FR 15406) and that would
therefore be the cutoff date establishing applicability.
The term "commenced" also raised problems as to what..exact
point, in time, construction or modification would be considered
by the administrator to have commenced. That point, as clarified
in the Background Information for New Source Performance Standards
regarding asphalt concrete and as defined in the standards (40 CFR
60.2), is when a ''contractual obligation" for construction or modi-
fication is made to undertake and complete, within a reasonable
time, a continuous program of construction or modification.
As to what constitutes a "modification", the regulation
(40 CFR 60.2) goes into some detail on that point. In general a
modification is construed to be "any physical change in, or change
in method of .iteration of, an existing facility which increases the
amount of any air pollutant (to which a standard applies) emitted
into the atmosphere by that facility or which results in the emission
of any air pollutant (to which a standard applies) into the atmos-
phere not previously emitted."
With respect to an existing portable asphalt concrete plant,
Standards of Performance for new sources do not apply to such a
plant following a change in its location unless such a change is
accompanied by an increase in its emissions rate as determined by
40 CFR 60.14.
9
Background Information for NSPS, Vol. 3, pg.9,
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2.4 Performance Test Requirements
As required by the Standards an operator shall submit the
results of a performance test performed "within 60 days after
achieving maximum production rate at which the affected facility
will be operated, but not later than 180 days after initial start-
up." (40 CFR 60.8)
Tests should be in accordance with EPA method 5 using
only the front half on the train to determine compliance. Three
separate test runs should be made with their arithmetic mean
determining the emission rate.
2.5 State Regulations
The inspector should be familiar with all applicable state
regulations before an inspection. He is therefore not only in-
specting for new source violations5 but also for violations of
state regulations as well. In this connection it is stressed that
the details of the state emission regulation and testing rules
be examined since they vary from one jurisdiction to the other,
sometimes in a major recognizable way, but also sometimes in
subtle,easily overlooked details such as the definition of
"condensible" particulate matter.
2.6 Emission of Hazardous Air Pollutants
Asphalt concrete plants using asbestos are subject to the
National Emission Standards for Hazardous Air Pollutants (40 CFR
61.22 (c) (11)). These standards contain a prohibition on visible
emissions to the outside air. Alternatively, the owner or operator
of an asphalt concrete plant using asbestos may elect to use the
air cleaning methods specified by 40 CFR 61.23.
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SECTION 3
THE ASPHALT INDUSTRY
In dealing with asphalt concrete plants it is important
to consider those attributes of their operation which bear on
plant inspections. The industry can be classified as a wide-
spread jobbing industry with a highly controlled product whose
single largest customeisarestate and local governments. Except
for one general type of product, all products have a technical
restriction on use which precludes inventorying of the product
except for very short periods. Thus the industry has the product
characteristics of other jobbing activities such as machine shops
and gray iron jobbing foundries _, but in addition it has a unique
restriction in that its main product cannot be stored for extended
periods of time and generally cannot be transported more than
two hours trucking distance.
The product of asphalt concrete plants is used for sur-
facing roads, airport runways, parking lots and driveways. It
has other smaller uses such a liners in sanitary landfills,
extruded curbs, and impoundment liners. About 70% of the product
is used in state and county roads. In 1970 1,846 firms operated
an estimated 4500 plants distributed nationally.1 The widespread
nature of the industry is a result of the national demand coupled
with the fact that the product must be used hot and most often
under strict state quality inspection. It is difficult to
store in heated silos, and state regulations often limit the
storage time. These limits are usually on the order of 24 hours.
This also accounts for the selected use of portable asphalt plants
where the plant moves to the job site, which is generally a large
project. Except for size restrictions for road hauling there
are few significant differences between portable and fixed plants.
Most plants (about 75%) are permanent plants and are primarily
located in urban areas, where there is a constant market for
their product.^
The technical requirement for hot product has its counter-
part in the temperature at the construction site. Not only must
Background Information for New Source Performance Standards, U.S.
Environmental Protection Agency, APTD-1352c (Feb., 1974), pg. 77.
2 Group Buying to Reduce Air Pollution Costs for Small Plants,
J. A. Commins and Associates (August, 1972), pg. 2-3.
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the product be at a certain temperature, but many states also
will not permit laying operations when the ambient temperature
at the job site is less than a specified minimum. The jobbing
nature of the work together with the technical restrictions
on use confront the inspector with the following:
• Depending on location some plants shut down in winter
• Product varies by job so that raw material content
which may bear on potential emissions also varies
• Plant operation is sporadic because it "follows" work
at a field site, and it is therefore difficult to
plan an inspection when the plant is operating at
maximum potential emission.
Approximately 300 million tons of asphalt concrete are
produced in plants that range from 50 tons per hour to about 400
tons per hour. A 150 ton per hour plant is considered average,
although,as in many industries, newly constructed plants tend
to have larger capacities. Although plants have rated capacities,
they frequently will operate below this figure due to the paving
type produced, aggregate moisture content, and other factors
that will be covered later in this manual.
With shipments in excess of three billion dollars per year,
the asphalt batching industry is in the top 10% of manufacturing
businesses. Growth trends depend on the amount of state and county
road building and general commercial building. The price of
asphalt paving mixture varies as to grade, size of job, etc., but
is usually very competitive.
Several important trends may affect the industry. One
involves the raw material, another the customer, and the third
the process. Asphalt cement is produced from refining crude
petroleum, a by-product of the refining process. In 1970 and
early 1971 a combination of supply problems ascribed to a
number of factors, such as lower domestic production of petroleum
coupled with higher prices for other product uses, including low
sulfur fuel derivatives, created a critical shortage. This situation
was relieved by mid-1971, but could again become troublesome.
Since most of the product manufactured by asphalt concrete
plants is used in the construction of state and county roads
(most federal roads are concrete) the health of the industry is
critically dependent on such government spending.
A process change, actually requiring the modification of
much of a plant, is the "Drum Mix Process." The use of this
process, also known as the turbulent mass process, is growing
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rapidly in the industry. It will not be described in this manual,
but will be covered by a separate addendum, which should be available
during the summer of 1976.
Another expected new trend is the increase in the use of
slag in wearing surface mixes to comply with skid resistance regula-
tions now being established in many states. This material trend will
also be treated in the addendum.
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SECTION 4
PROCESS DESCRIPTION
The process flow in an asphalt concrete plant can best
be thought of in terms of the finished product. Asphalt con-
crete is basically a combination of aggregate that is dried,
heated and then evenly coated with hot asphalt cement.
4.1 Batch Plant
The process can be followed from Figure 4-1. This
diagram satisfactorily shows process flow, but does not ad-
equately represent the air pollution control equipment. Section
7 has a diagram more representative of the pollution control
flow.
The process begins with the loading of different sized
aggregate from stockpiles, usually into four "cold" bins as
shown at the far left. From these cold bins calibrated vi-
bratory feeders control the amounts of each aggregate falling
onto a conveyor that leads, either directly or by means of a
bucket elevator, to the inlet of the dryer. The function of
the dryer is to remove surface moisture and heat the aggregate
to between 250 and 350°F in order to be coated with asphalt
cement in the pugmill.
The dryer is an inclined rotary drum, typically on
the order of 9 feet in diameter and about 40 feet long, in
which the aggregate is dried and heated by an oil or gas burn-
er. The dryer is designed with 'flights' on the inside that
tumble the aggregate and increase exposure to the hot gases.
The burner is generally located at the aggregate discharge or
low end of the dryer; therefore, the combustion gases flow
counter current to aggregate flow. Some dryers, however, are
fired from both ends with a center outlet for exhaust gases.
Dryer capacities are often rated as a function of aggre-
gate surface moisture content. This is frequently 5% and often
at a specified fines content (particles less than 200 mesh or
74 microns). Unusually wet aggregate, or aggregate containing
Air Pollution Engineering Manual, 2nd Edition, U.S. Envir-
onmental Protection Agency, AP-40 (May,1973), pg. 326.
11
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large percentages of fines, requires either increasing fuel
to the burner or decreasing aggregate cold feed rates to in-
sure proper drying. Thus a plant's capacity is not a single
point, but a range dependant on the characteristics of the cold
aggregate. The effluent gases from the dryer are almost always
directed to a primary collector if a wet secondary is used.
In the case of a fabric filter secondary, the primary cyclone
is often used, although there are instances where a cyclone is
not used. The dry collected material is either stored to be
partially metered back into the weigh hopper or transported
directly to the hot elevator.
From the discharge end of the dryer the heated aggre-
gate is transported by the "hot elevator" to a set of vibrating
screens located over the hot bins in the batching tower. These
screens sort the aggregate according to size and drop it into
the appropriate hot bin. Oversize material and material from
overfilled bins is discharged via a reject chute. It is from
these hot bins that each size aggregate is weighed in the weigh
hopper according to mix specifications and dropped into the
pugmill. Additional mineral filler, when necessary, is added
either from a control device discharging collected material
onto the hot elevator or onto the weigh hopper. The aggregate
is then mixed dry for a few seconds before a fixed percentage of
asphalt cement is pumped in from heated storage. Mixing then
lasts an additional thirty to forty seconds after which the com-
pleted batch of asphalt is dropped into waiting trucks. Some
plants convey the finished batch to a product storage silo from
which the trucks are loaded.
The hot elevator, screen area, weigh hopper and pugmill
are often connected by "scavenger" ductwork back to the primary
collector. There are isolated instances where the scavenger air
has its own separate control.
Figure 4-2 is a picture of an asphalt batch plant.
An identification sketch accompanies, as Figure 4-3.
4.2 Continuous Plant
The basic operation ( as shown in Figure 4-4) is similar
to its counterpart in the batch plant, except in the method of
feed to the pugmill (mixer), and in the pugmill itself. The hot
aggregate drops from the sorting screens into hot bins that
are sized smaller than those in the batch plant process. From
these bins continuous flow is metered according to specifica-
tions; the aggregate mixture is then conveyed to the pugmill
inlet, into which hot asphalt cement is metered simultaneously.
The feeder systems for aggregate and asphalt are mechanically
interconnected to insure proper proportions in the mix. The
mixture is then conveyed by mixing paddles to the outlet end
12
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Figure 4-1
ASPHALT BATCH MIX PLANT - AN EXPLODED VIEW
GRADATION CONTROL UNIT
Separates and store* dried aggregate.
Mean/res and feeds the required amount of
each size.
TO SECONDARY COLLECTOR
Vibrating screens separata aggregates
into proper sizes and reject oversize.
COLD AGGREGATE STORAGE
AND FEED
Stores aggregate and accurately feeds the
required amount of each size to maintain
constant balance of aggregate in gradation
unit.
CYC LOWE
Mineral filler feed feij uniformly b
Recovert fines that may be returned to the
mix, if required.
Continuous flow of aggregate receives maxi-
mum drying through direct contact with
flame and hot gases. Each aggregate par-
ticle it repeatedly exposed for greatest
drying.
Weigh-hopper measures all sizes or
aggregate, including mineral filler.
Grizzly protects dryer from oversize and
foreign material.
Jockeyed asphalt weigh-bucket measure
correct amount asp'iclt for each botch
Fan develops conlrolled gas and air flow
for dryer combustion system and dust
collector.
Collected fines fed by screw conveyor to
boot of hot elevator.
3elt ft*dcr under sand bins hos adjusf-
oble gates. Wide angle of contact be-
tween send ond belt minimizes voids.
Reciprocating feeder under stone bin;
has adjustable gates.
Flights drop aggregate in uniform veil
through flame and hot gases for greatest
drying.
Mineral filler feeding ond i
system stores material at ground level.
Source: Asphalt Plant Manual, The Asphalt
Institute, 1967
13
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of the pugmill where the mix is discharged continually into a
holding hopper. The time for the mixing cycle and some surge
capacity is controlled by an adjustable dam at the end of the
pugmill. Mixing time can be changed without varying hourly
tonnage output simply by changing the height of the adjustable
dam, and consequently the rate of outlet flow.
Many plants are completely automated (some state De-
partments of Transportation require this) so that all of the
operations except loading the cold aggregate into the cold
storage bins are controlled from a cental control center by
manual pushbuttons or digital card controlled sequence.
4.3 Cold Patch
Cold patch or liquid asphalt mixes can often be produced
in both continuous and batch plants. Some varieties of cold
patch can be made in a simple open pugmill or revolving drum.
Cold patch differs from regular asphalt in that the
asphalt cement used, called cut-back asphalt, has mineral oils
or solvents added which give it better aggregate coating pro-
perties and extend curing times. The increased coating pro-
perties associated with cut-back asphalt cement reduce aggre-
gate temperature requirements considerably, therefore allowing
the dryer to run at lower temperatures.
Cold patch is used for low traffic volume paving, small
patch work, and hand spreading in small areas. It does not
possess the strength properties of hot mix, but its long cure
time results in a more workable product which is desirable in
some situations.
4.4 Automation
There are many aspects of production in asphalt concrete
plants that lend themselves to automation. A trend toward some
degree of automation is currently noticeable in the industry.
Various automatic functions include burner and damper
settings for consistent drying and heating of the aggregate,
safety sensors and controls for protection of control equip-
ment, weighing of fines captured in the control system as they
are reintroduced in the mixing tower, and recording of all mix
parameters for process control and instant billing of customers.
Such automatic functions are desirable from an emission
stand-point because they tend to stabilize the process conditions
amd minimize shutdowns.
Asphalt Plant Manual, 3rd Edition, The Asphalt Institute,
March,1967, pg. 65.
15
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Figure 4-2
AN ASPHALT BATCH PLANT
Source: The McCarter Corporation
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Figure 4-3
DIAGRAM OF AN ASPRALT BATCH PLANT
(19)
^\ l
rQ
^**««,
r- 1
^
(n
2
3
4
5
6
7
8
(9)
1 A
11
11 II \
11 » 12
13
LEGEND
Cold Feed Bins
Cold Feed Conveyor
Dryer Feed Chute
Rotary Dryer
Hot Elevator
Hot Screens Area
Hot Bins Area
Weigh Hopper
Pugmill
Burner
Exhaust Duct to
Primary Collector
Primary Collector
(Cyclone)
Duct: Primary to
Secondary Collector
Secondary Collector
(baghouse)
(14) Fan
15 Stack
16 Scavenger Ductwork
17 Control Cabin
18 Truck Loading Area-
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Figure 4-4
ASPHALT CONTINUOUS MIX PLANT - AN EXPLODED VIEW
TO
COLLECTOR
COLO AGGREGATE STORAGE
AND FEED
Stores oggregote and accurately feeds the
required amount of each size to maintain
constant balance of aggregate in gradation
unit.
DRYER
Continuous flow of aggregate receives maxi-
mum drying through direct contact with
flame and hot gates. Each aggregate par-
ticle h repeatedly exposed for greatest
drying.
MIXER
Automatically meters the correct amount nf
asphalt and thoroughly mixes the material
in the twin-shaft pugmill. Aggregate and
asphalt feeds are positively interlocked.
Grizzly protects dryer from oversize and
foreign material.
Beit feeder under sand bins has adjyit-
obi* o,ct9i. Wide angle of contact be-
tween wnd and belt minimizes void*.
Reciprocating feeder under (tone bin!
has adjustable gates.
RKOV.M (In., ihrt mo, b. rttuin.d to 'he
mix, if rtquirod.
GRADATION CONTROL UNIT
Separates ond stores dried aggregate.
Measures and feeds the required amount of
each size.
Vibrating screen* separate aggregate
into proper sizes ond reject
Twin-shaft pugmill thoroughly
material.
Fan controls air flow for drye
tion system and dust collector.
Individually adjusted gatei accurately
proportion required percentage of each
aggregate.
Mineral filler feeding ond mea
system stores material at ground level
Collected fines fed by screw conveyor to
boot of hot elevator.
Flights drop aggregate in uniform veil
through flame ond hat gases for greatest
drying.
Individual aggregate samples quickly
and easily token by diverting flow of
material into test containers
>sitivo displacement m«
jrlocksd with oggrftfji
ately proportions asphalt
chamber.
hopper allows continuous
between trucks, prevents
segregation.
Source: Asphalt Plant Manual, The Asphalt Institute, 1967
19
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SECTION 5
RAW MATERIALS
The basic raw materials used in the product of asphalt
concrete are: various types and sizes of aggregate, asphalt
cement and fuel for the dryer. A general discussion of each
of these materials follows.
5.1 Aggregate
The term aggregate refers to the various sizes and types
of gravel, crushed stone, slag, sand and mineral filler used in
the production of asphalt concrete.
Asphalt concrete is classified into various mix types
according to the particular blend of aggregate used. Basic
aggregate size ranges are: coarse aggregate, larger sized stone,
which can range up to 2 1/2" in diameter; fine aggregate,which
consists of natural sand and finely crushed stone, slag or gravel;
and mineral filler generally consisting of very fine crushed stone,
hydrated lime, Portland cement or any other suitable non-plastic
mineral filler. The material recovered from any dry air cleaning
device is often used as mineral filler in the mix.
The transportation department in each state has mix
specifications for each type of asphalt produced. These speci-
fications will dictate the percentages of each size aggregate
to be used in the mix. Aggregate properties such as skid
resistance, friability and soundness are also specified by some
states. Mix specifications are generaly monitored by state in-
spectors when the asphalt is being used for state work. This
involves an extraction and sieve analysis to determine whether
the asphalt being produced is within specification.
5.2 Asbestos
The addition of small percentages of asbestos to the mix
produces an "improved pavement overlay with increased cohesion
and abrasion resistance and decreased water permeability and
material embrittlement.nl
•*• Control Techniques for Asbestos Air Pollution, U.S. Environmental
Protection Agency, AP117 (Feb.,1973), pg. 3-40, 41.
21
-------
Asbestos is generally added directly into the pugmill
during mixing. Sealed poly-bags are often used to prevent
hazards during material handling. When asbestos is added in
these bags little or no emission of asbestos would be expected.
5.3 Asphalt Cement
Asphalt cement is a residual by-product of the petroleum
cracking process. It is very viscous at ambient temperatures;
therefore it must be heated to 275°-325°F so that it can be
pumped and mixed easily in the pubmill. Various types and
grades of asphalt cement are available for various mix types.
Asphalt cement is added, usually around 5% by weight of the
asphalt concrete produced.
5.4 Cut-Back Asphalt
Cut-back asphalt is a less viscous binding agent used
in the production of "cold patch" asphalt mixes (described
in Section 4-3).
It is produced by the addition of mineral oils or sol-
vent to regular asphalt cement. The added mineral oils in this
asphalt cement are responsible for the longer curing times and
better coating properties associated with cold patch asphalt.
5.5 Fuel
Natural Gas, LPG, or #2 oil are the fuels most commonly
used for the burner. Lower grades of oil (#5;#6) can be used;
however, it is necessary to preheat these oils prior to combus-
tion.
22
-------
SECTION 6
EMISSIONS
Air pollution emissions from asphalt concrete manufac-
turing plants are both gaseous and particulate in nature. The
new source regulations 40 CFR 60.92 apply only to particulate
matter and opacity. The other emissions are not under stan-
dards of performance for new sources.
Several of the emissions from hot mix plants shown in
Table 6-1 are emitted in negligible quantities and do
not warrant special gas cleaning considerations. Combustion
products, for instance, including sulfur dioxide, carbon mon-
oxide, soot and unburned fuel droplets pose no problem quan-
titatively; such emissions can be minimized through proper
combustion equipment maintenance and through the use of clean-
er fuels. The common pollutants from an asphalt batching
plant are briefly described below.
6.1 Sulfur Compounds
These are emitted from asphalt plants when fuels which
contain sulfur are burned to dry the aggregate. The amount
of sulfur oxides formed may be calculated from the sulfur con-
tent and usage rate of the fuel.* The amount actually released
into the atmosphere may be controlled by wet scrubbers.
* Ibs. S02 = .142 (%S) (Distillate oil)
gal. fuel oil = .157 (%S) (Residual oil)
The weight of sulfur dioxide emitted expressed in Ibs. per gal.
of fuel oil burned equals .157 times the percentage. It should
be expressed as such in the equation rather than as a decimal
fraction. (For 1%, enter "1" rather than "0.01.")
Air Pollution Control Technology and Costs in Nine Select-
ed Areas, Industrial Gas Cleaning Institute, Inc., (Sept,1972),
Pg. 122.
23
-------
TABLE 6-1
TABLE OF EMISSIONS AND SOURCES
Major Emissions - Particulates
1. Stone dust - primary pollutant from hot mix asphalt: main
source is the dryer; secondary sources are screening, con-
veying and handling of aggregate, and storage piles and
access roads.
2. Unburned fuel oil droplets - result from poor combustion
due to improper component maintenance.
3. Soot - unburned carbon particles emitted due to insuffi-
cient oxygen at the dryer or heater burners.
4. Asbestos - hopper loading; discharge of dry fiber while
loading into the pugmill. This additive occurs for speci-
fic mixes. Use of pre-weighed poly bags loaded directly
into pugmill will minimize or eliminate these emissions.
Lesser Emissions - Gases
Combustion
a. S02 - results from combustion of high sulfur fuel oil
in burners and heaters
b. CO - poor combustion maintenance of burners, dryer
and heaters
Mixer
Hydrocarbon emissions result from mixing of asphalt and
from dryer combustion gases.
Hot-mix trucks
Odors primarily attributable to oxidation of liquid asphalt
after encountering hot aggregate; odors may also be gener-
ated from oil that is sometimes sprayed on truck bodies
to prevent the product from sticking
Asphalt Tanks
Hydrocarbon vapors and associated odors from heated asphalt,
and sometimes fuel storage tanks.
Adapted from: Air Pollution Control Technology and Costs in Nine
Selected Areas, Industrial Gas Cleaning Institute,
Inc., Sept., 1972.
24
-------
The use of slag as aggregate is suspected to emit small
quantities of hydrogen sulfide but little data is available on
this.
6.2 Odors
These may evolve from four potential sources: from the
hot asphalt, from inefficient burner operation, from the fuel
oil that is sprayed on truck bodies to prevent the asphalt from
sticking and under some conditions when slag is used in the
aggregate. Odors are increased if mixes are run hot and highly
volatile asphalt is used. Further, inefficient burner opera-
tion could generate aldehydes and organic acids which have a
pungent, acrid odor.
6.3 Hydrocarbons
Asphalt is a heavy residue from the refinery process.
As such, it contains various polynuclear hydrocarbons, includ-
ing anthracene, 3, 4-benzopyrene, phenanthrene and pyrene.2
Because of their high boiling points these compounds vaporize
readily only at elevated temperatures. (They are suspended
in the air as condensed particles or by adsorption to air-
borne particles.) A wet scrubber has been shown to reduce
hydrocarbon emissions effectively. Emissions from asphalt
storage tanks along with emissions from loading asphalt con-
crete into trucks can be vented into the dryer as part of
the combustion gases. This, however, is not commonly done.
6.4 Particulates
Although regulations are nearly always aimed at stack
emissions, complaints frequently arise from fugitive particu-
late emissions from truck traffic and aggregate stockpiles as
well. Such sources notwithstanding, particulate emissions
from drying and handling of aggregate are the chief air pol-
lution problems.
In the process, particulates derive from fines purpose-
ly introduced into the material to meet the state specifications
and from breakup of the material in the drying, conveying, screen-
ing and weighing operations. In an uncontrolled plant over 50%
of all particles.: less than 74 microns introduced into the dryer
become airborne.^ This could represent as much as 10% of the
^ "Polynuclear Hydrocarbon Emissions from Selected Industrial
Processes," Van Lehmden, Hangelrauk and Meeker, JAPCA 15,
No. 7 July, 1965, pg.307.
3 Ibid, pg. 309
4 Air Pollution Engineering Manual, U.S. Environmental Protec
tion Agency, AP-40, May, 1973, pg. 328.
25
-------
process weight. Table 6-2 lists typical dust discharge from
asphalt batch plants.
A plant producing 150 tons of paving material per hour,
for instance, will have uncontolled particulate emissions on
the order of 6,000 Ibs. per hour.^ Approximately 70-80% of that
amount is from fine aggregate material that becomes entrained
in the gas stream of the dryer; the remaining portion is con-
tributed from elevators, screens, pugmill and other aggregate
handling points. Collection of dust from these secondary
sources is accomplished by what is known as a scavenger or
fugitive dust system. The particulates collected in the hooding
and ductwork of the scavenger system are usually routed to the
inlet of the primary collection device; in some instances, how-
ever, the scavenger collector may have a separate gas cleaning
system.
Several operational variables can significantly affect
particulate emissions. Emission rates from the dryer will be
proportional to increases in gas velocity in the dryer, rate
of rotation of the dryer and feed rate. Balancing these vari-
ables for maximum drying efficiency and minimum emissions
is important to both process and control. All of these vari-
ables are dependent on the properties of the aggregate being
dried. Particle size distribution of feed, for example, has an
appreciable affect on discharge of dust. Therefore, mixes con-
taining large percentages of fine aggregate will produce great-
er uncontrolled dust emissions from the dryer.
Also, when wet aggregate is being dried the fuel rate
to the burner is often increased, thereby requiring additional
draft air and consequently greater velocities in the dryer.
This will increase the amount of material entrained in the gas
stream of the dryer.
The friability of the aggregate and coatings of clay and
silt will also affect emission.
6.5 Asbestos
When asbestos is added in the form of poly bags directly
• into the pugmill little or no emission of asbestos would be ex-
pected if proper operating techniques are followed. Proper opera-
ting techniques require that the pugmill be enclosed as soon as pos-
sible after the sealed poly bags are placed in it. No visible
emission of asbestos dust should emanate from the mill after the
poly bags have been added. If significant visible emission of
asbestos does occur, violation of the applicable National Emission
Standards for Hazardous Air Pollutants is indicated.
5 Ibid.,pg. 325.
26
-------
TABLE 6-2
DUST DISCHARGE FROM ASPHALT BATCH PLANTS
Batch Plant Data
Mixer capacity, Ib.
Process weight, Ib/hr.
Dryer fuel
Type of Mix
Aggregate feed to dryer, wt
+10 mesh
-10 to +100 mesh
-100 to +200 mesh
-200 mesh
Dust and fume data
Gas volume, scfm
Gas temperature, °F.
Dust Loading, Ib/hr.
Dust loading, grains/scf
Sieve analysis of dust, wt .
+100 mesh
-100 to +200 mesh
- 200 mesh
Particle Size of -200 mesh
0 to 5u, wt. %
5 to 10u,wt. %
10 to 20u,wt. %
20 to 50u,wt. %
50u, wt. %
* Vent line (scavenger air)
hopper, and pugmill.
6,000
364,000
Oil, PS 300
6,000
346,000
Oil, PS 300
City street, surface
. %
70.8
24.7
1.7
2.8
Vent line*
2,800
215
2,000
81.8
%
4.3
6.5
89.2
19.3
20.4
21.0
25.0
14.2
Dryer
21,000
180
6,700
37.2
17.0
25.2
57.8
10.1
11.0
11.0
21.4
46.5
Highway,
68.1
28.9
1.4
1.6
Vent line*
3,175
200
740
23.29
0.5
4.6
94.9
18.8
27.6
40.4
12.1
1.1
surface
Dryer
22,050
430
4,720
24.98
18.9
32.2
48.9
9.2
12.3
22.7
49.3
6.5
serves hot elevator, screens, bin, weigh
Source: Air Pollution Engineering Manual,, 2nd edition, p. 328.
27
-------
-------
SECTION 7
CONTROL OF PARTICULATE EMISSIONS
To attain participate emission levels prescribed by
federal performance standards? 90 mg/scm (0.04 gr./dscf), new
asphalt concrete manufacturing plants will have to reduce their
uncontrolled emissions by at least 99%. Figure 7-1 is a flow
diagram showing the route of emissions through a control system
using a baghouse. Emissions from the dryer and the scavenger
(fugitive dust) system are routed to the inlet of the primary
collector (in Fig. 7-1, a cyclone), when used, where the greater
percentage of large particles is collected. The particulate
matter collected in the primary collector is generally reintro-
duced into the mix at the hot elevator. Such capture and recycl-
ing is desirable for bringing the fines content of the mix to
specifications. Primary collectors are often unnecessary with
baghouses. The effluent gas from the primary collector or pre-
cleaner then goes to the secondary collector, which may be any
high efficiency wet or dry collector capable of achieving the
grain loading limitations (in Fig. 7-1, a baghouse).
Control units and strategy will be discussed for both
primary and secondary collectors in the following sections.
7.1 Primary Collectors
The function of the primary collector is to remove most
of the entrained dust (50 to 90% by weight), predominantly the
large size particles. The most common primary device is a large
diameter cyclone. Twin and multiple cyclones are also used.
The cyclone operates on the centrifugal force principle and can
be quite efficient for particles greater than 20 microns. The
overall efficiency of the cyclone depends upon particle size and
pressure drop across the device, which is usually 2 to 4 inches
of water. Table 7-1 shows a typical particle size distribution
before and after the primary collector. Figure 7-2 shows a typi-
cal cold feed gradation and primary dust collector inlet grada-
tion. Note that while most of the particles entering the collec-
tor are between 10 and 100 microns,. approximately 50% are below
30 microns. The dust leaving a primary collector, of course,
depends on the input loading, size distribution and efficiency
of the collector, but is usually in the range of 5 to 12 Ibs./ton
of feed.
29
-------
FIGURE 7-1
EMISSIONS ROUTE THROUGH TYPICAL CONTROL SYSTEM
Dust-Laden Gases
Dust Laden Gas
Sand and
Aggregate
Bins
r
r
Vibrating
Screens
~1
Cold Aggregate
Bucket Hlevator
Weigh
Hopper
Hot Aggregate
Bucket Lilevator
Baghousc
Stack
Fan
-------
FIGURE 7-2
TYPICAL COLD FEED GRADATION AND PRIMARY
DUST COLLECTOR INLET GRADATION
200 mesh
325 mesh
100
80
60
50
~40~
Cumulative percont passing
95 90 80 70 60 50 40 30 20 10 5 I
~ 30
w
c
o
.*; 20
- 10
o 8
o
o
a.
O.i
0.01
\
\
Cold feed
gradation
\
Oust collector—' *1
inlet gradation
10 20 30 40 50 60 70 80 90 95
Cumulative percent larger
99
99.9
99.99
Source: Guide for Air Pollution Control
of Hot Mix Asphalt Plants, National
Asphalt Pavement Association
31
-------
TABLE 7-1
PARTICLE SIZE DISTRIBUTION
BEFORE AND AFTER PRIMARY COLLECTION
FROM
Size/T
5
10
15
20
25
30
35
40
45
DRYER AND VENT
% Less Than
19.5
30.5
38.2
45.1
50.1
55.5
60.0
64.0
67.5
FROM PRIMARY COLLECTOR
Size/? % Less Than
5
10
15
20
25
30
35
40
45
78.00
96.40
97.50
97.80
97.90
98.03
98.20
98.28
98.40
Source: Air Pollution Control Technology And Costs In
Nine Selected Areas Industrial Gas Cleaning Institute
32
-------
7.2 Secondary Collectors
For an average size plant using a primary collector
grain loadings entering the secondary collector range between
2.9 and 6.0 gr./dscf. In order to reduce such grain loadings
to the specified standard (90 mg/scm or 0.04 gr./dscf), the
secondary collector must have a collection efficiency of 99%
or better.
Other factors influencing the selection of a secon-
dary control device include plant mobility, space and power
availability, water supply and waste water considerations,
and the desirability of -#200 mesh material for use as miner-
al filler either in production or for commercial sale.
Hi-Energy Venturi Scrubbers. Several different designs
of venturi scrubbers exist» three of which are shown in Figure
7-3. Nevertheless, their operating principles are essentially
similar. These scrubbers, with pressure drops in the range of
20 inches of water, or greater, generally are capable of reduc-
ing emissions to below the required 90 mg/scm (0.04 gr./dscf)
level prescribed in the federal standard.
The venturi scrubber is a high efficiency wet collector
that operates by impinging particulates on atomized water droplets.
The effective mass of the particle thus increased, cyclonic sep-
aration is then possible.
As the particle laden gas enters the device a constric-
tion reduces the cross-sectional area of the gas stream, there-
by increasing the stream velocity. This correspondingly increases
the velocity of the particles relative to the formerly stationary
water droplets that were introduced at the apex of the constric-
tion. Increasing the relative speeds heightens the probability
that a particle will impinge upon the water droplet. As the dust-
laden water droplets leave the venturi constriction they further
agglomerate due to deceleration. The gas stream then passes
through a cyclonic separator, which removes the larger, heavier
particles formed during the agglomeration phase.
Venturi scrubbers can achieve collection efficiencies in
excess of 99%. Variables affecting efficiency include pressure
drop, water injection rates, venturi design, and particle con-
centration and size. Collection efficiencies improve with higher
pressure drop, attainable by increasing the throat velocity by
constricting the throat and, to a lesser extent, by increasing
the water injection rate. Pressure drops will probably be 20"
or more for most venturies, while water injection rates normally
encountered will nominally be 6 and 10 gallons of water per
33
-------
FIGURE 7-3
VENTURI SCRUBBER
Venturi scrubber may feed liquid through jets (a),
over a weir (b), or swirl them on a shelf (c).
Source: Control Techniques for Particulate
Air Pollutants, USDHEW i.y&y
34
-------
minute per 1000 acf of gas. Efficiencies fall rapidly at in-
jection rates below this range; rates in excess of 10 gallons
of water per minute per 1000 acf of gas produce lesser increases
in collection efficiencies.
Greater particle concentration also improves collec-
tion efficiency. Assuming the number of water droplets formed
in the system is constant, the frequency of particle collisions
is increased when more particles are introduced into the system.
Figure 7-4 shows a nominal collection efficiency and particle
size relationship for a typical wet scrubber. Note that the
efficiency is greater than 97% for particles large than 1.5
microns; note too that the efficiency falls sharplv for par-
ticles less than one micron for a fixed set of conditions.
Disadvantages of venturi scrubbers include high oper-
ation costs associated with producing high pressure drops
and also the need for large quantities of water, which entails
elaborate recycling of alkaline, acidic or odoriferous water.
This would require the use of settling basins, which also pre-
sent a problem of solid waste disposal when they must be
dredged.
Advantages of venturi scrubbers include their relative-
ly low initial cost, their ability to partially control the
hydrocarbon emissions2 received from the pugmill, and the lack
of need for pre-conditioning the input gas.
Low Energy Wet Scrubbers. These commonly used devices
include spray towers, wet fans or any other wet collector with
a pressure drop less than 15 inches of water. The major para-
meters affecting the performance of these scrubbers are water
injection rates and pressure drops. They are generally not ef-
fective in light of the efficiencies necessary to achieve 90
mg/dscm CO.04 gr.scf). It is, however, possible to achieve grain
loadings less than 90 mg/dscm (.04 gr/dscf) using two or more of
these devices in series following a primary collector.3
Small Diameter Cyclones. Banks of small diameter cy-
clones (multi-cyclones), have the advantage of collecting dust
in a usable form which is usually returned to the process.
Air Pollution Engineering Manual, 2nd Edition, U.S. E.P.A.,
AP40, May, 1973, p~33T.
Von Lehmden, Hangebrauk and Meeker, "Polynuclear Hydrocarbon
Emissions from Selected Industrial Processes", JAPCA 15,
no. 7, p. 309.
Background Information for New Source Performance Standards,
U.S. E.P.A., (APTD-1352c), February,1974, p.10.
35
-------
FIGURE 7-4
EFFICIENCY vs. SIZE FOR TYPICAL VENTURI
O1
O
X
o
0)
o
o
0)
o
u
345
Particle Size, Microns
8
Source: Control of Particulate Emissions,
USDHEW
-------
The high velocities demanded by these small cyclones can cause
failure due to abrasion; furthermore, these devices do not per-
form well when overloaded.
With tube diameters of from six to nine inches and pres-
sure drop of from 3 to 6 inches of water, the efficiency should
be between 80 and 90% -- generally not sufficient to achieve
90 mg/dscm (0.04 gr./dscf).4
Fabric Filters. Fabric filters, commonly referred to
as baghouses, readily attain collection efficiencies in excess
of 99% if they are properly operated and maintained. Opera-
tion basically consists of directing particle laden air through
an appropriate fabric, which is chosen for its heat resistance
capabilities as well as its filtering capabilities. The fab-
ric design often encountered in asphalt plants is 14 oz. Nomex*
felt or woven construction.
As dust particles accumulate on the fabric, pressure
drop across the device increases. The filters are generally
cleaned on a time cycle that is correlated to this pressure
drop increase. Various types of cleaning mechanisms are en-
countered in asphalt plant operation and they seem to be in-
digenous to the particular manufacturer. The only common
operational technique is that the cleaning operation does
not require stopping the process, and hence is called con-
tinuous cleaning. There is the reverse flush type where a
single compartment is flushed from time to time by a series of
valves which close off a given compartment while outside air
or pressured air is used to "flush" all the bags in that com-
partment. Another approach is to use blow down pipes located
above the rows of bags. Compressed air is directed into a num-
ber of these pipes simultaneously on staggered rows and es-
capes through small holes above each bag sometimes entering
the bag through a small cast venturi (see Fig. 7-5). This
air cleans the dust from the bag, the automatic process being
repeated sequentially. The frequency of blow down, the dur-
ation and the amount of air pressure can frequently be ad-
justed by the operator, and sometimes the cleaning frequency
is automatically controlled by a pressure sensing device. As
the bags are subjected to wear the no load permeability of
the cloth will change and appropriate adjustments should be
made to the blow down frequency.
Control of Particulate Emissions, USDHEW Section V, pg. 20
Handbook of Fabric Filter Technology, C. Billings and J.
Welder for U.S. Department of Health, Education and Wel-
fare, December 1970, pp. 1-4.
Trade Name - The DuPont Company
37
-------
FIGURE 7-5
TYPICAL PULSE-JET CONFIGURATION
Aif—--
Source: Handbook of Fabric Filter Technology, GCA Corp., Dec. 1970
-------
Air-to-cloth ratio or superficial face velocity refers
to the ratio between the volumetric flow rate and the effective
filter area. The air-to-cloth ratio for the reverse pulse and/
or jet pulse cleaning baghouses is nominally 6 acfm per square
foot of filter area. The reduced bag area required for such
baghouses has made them the most widely used in asphalt plants.
There are several design considerations in using bag-
houses on hot mix asphalt plants; both the major problems are
associated with temperature and moisture. Temperatures must
not exceed limits dictated by the fabric used, while at the
same time, they must be kept high enough to prevent conden-
sation of any moisture in the gas stream. Failure to main-
tain temperatures above the dew point results in blinding or
clogging of the filter fabric.
In many instances special temperature regulating sys-
tems are employed. These may include insulation of the bag-
house, introduction of tempered air (either hot or cold), and
special alarm or override systems to prevent damage to the
baghouse. Proper operational techniques are also called for.
The burner and fan should be operating for a short time at start
up without introducing cold aggregate to the dryer, and the
burner and fan should also be run for several minutes after
the feed is stopped. This is to clean out the system of col-
lected materials and to make sure the baghouse is above the
dew point before introducing moisture laden gas.
Advantages of baghouse filters are: high collection
efficiencies, the ability to recycle collected material; rela-
tively compact unit size; no water usage and low power consump-
tion. However, baghouse filters are generally not applicable
to the control of drum-mix plants.
Electrostatic Precipitators. The low gas volumes as-
sociated with asphalt concrete plants and the high capital in-
vestment required generally make electrostatic precipitators
impractical. They can, however, attain collection efficiencies
of over 99% and can reduce emissions to the levels required by
the standards of performance.6 Equally important is the fact
that they use little electric energy.
The precipitator very basically consists of two elec-
trodes, a discharge electrode (usually a vertical wire) and
a collecting electrode (usually a plate on the side of the
unit), between which a unidirectional high potential field
is created. The potential difference is approximately 70,000
volts. The exhaust gas is then passed between these electro-
des and ionization of the air takes place at, or near*the sur-
face of the discharge (negative) electrode. The negative ions
move toward the positive collection surface and the positive
ions move toward the negative collection surface, or discharge
Stack Test Performance by JACA Corp. for compliance with
Pennsylvania Regulations.
39
-------
electrode. As these ions move they impinge upon the neutral
particles in the gas stream; these charged particles then mi-
grate toward the appropriate electrode. Charging of the neu-
tral particles takes place in the first few inches of the field.
The negative ions have a greater distance to travel
than the positive ions, which are formed near and move toward
the negative electrode. Therefore, the negative ions have a
much greater chance to contact particles, resulting in the
greatest possible collection at the positive electrode or col-
lecting plate.
When the charged particles contact the electrodes they
become neutral, and their removal can be accomplished by rap-
ping (mechanical vibrating), washing or gravity. It is impor-
tant to vibrate or rap at a magnitude and rate such that re-
entrainment will be minimized.
The high costs of electrostatic precipitators, their
complexity and the comparatively specialized technology re-
quired for their maintenance (e.g., special treatment is neces-
sary for resistant particles, etc.) makes their common instal-
lation impractical.
Table 7-2 is a brief and simplified presentation of
comparative control device characteristics.
"Control of Particulate Emissions," Course Manual, U.S. De-
partment of Health, Education and Welfare, p. E.S.P. 1.
40
-------
Table 7-2
CONTROL DEVICE CHARACTERISTICS
Control
Device
Cyclone
Wet
Scrubber
Baghouse
(Fabric
Filter)
Electrostatic
Precipitator
* Gas
Principle of
Operation
Separation of
particles by
imparting centri-
fugal force
Centrifugal
force: effective
particle size
increased by agg-
lomeration with
liquid droplets
Through- flow sep-
aration as in a
vacuum cleaner,
operation based
on cake filtra-
tion
Attraction of
electrically
charged parti-
cles to oppo-
site-charged
plates
conditioning must
1.
2.
3.
1.
2.
3.
1.
2.
3.
4.
1.
2.
3.
be
Typical
Principal Overall
Design Efficiencies ,
Variables Percent
Length of
cyclone tube/s
Diameter of 45-80
cyclone tube/s
Fan horse-
power
Throat veloc-
ity of gas
Liquid in- 85-99
jection rate
Fan horse-
power
Fabric mater-
ial
Air-to-cloth 95-99+
ratio
Cleaning time
and sequence
Fan horse-
power
Space between
electrodes
Voltage across 95-99+
plates
Fan horse-
power
used at higher temperatures
Typical
Pressure Operating*
Drops , Temperature
inches L imi tat ion ,
of water °F
2-5 1,200
5-40 250
5-10 550
3-8 1,000
**This aspect will be
Particle
Removal
in the
Form of
Dry dust
Wet
slurry
Dry dust
Dry dust
treated in j
tail in the "drum-mix" addendum
Other
Limitations
Inefficient
particle re-
moval under
20 microns
Corrosive
action of wet
gases affects
operation. Pos-
sible water pol-
lution problem '
may be encoun-
tered.**
Possible cake
i • -i i ,
build up at
operation be-
low dew point.
Application
limited to a
certain range
of dust resis-
tivity
greater de-
to this manual
Source: Group Buying to Reduce Air Pollution Costs for Small Plants, J. A. Commins and Associates (Aug. '72).
-------
-------
SECTION 8
INSPECTIONS
Previous sections of this manual provided background
information on regulations, industry, process description,
potential emissions and control techniques. This section sets
forth detailed methodology to be employed for field visits in
monitoring performance tests on new sources and in performing
field inspections in the period subsequent to performance testing.
8.1 General Inspection Background
The purpose of monitoring a stack performance test is to
help assure three items:
1. That the test is conducted in accordance with the
methods specified in the Standards of Performance
for new or modified asphalt concrete plants.
(40 CFR 60.93)
2. That the test is conducted under such process con-
ditions as the Administrator shall specify to the
plant operator based on representative performance
of the affected facility.
3. That pertinent process data is complete and accurate
for the period under test.
The purpose of field inspections is to examine the plant for
these items:
1. Plant opacity compliance.
2. Comparison of readily identifiable key process and
control parameters with the same parameters contained
in the initial permit application or reported during
a successful performance test.
3. State of maintenance.
4. Proper operation procedures and settings for the air
pollution control devices.
5. Determination of whether the Standards of Performance
are applicable to the plant.
8.2 Setting Up The Visits
Performance Test Monitoring. The new source standards
(40 CFR 60.8) require that the owner or operator of an affected
facility shall provide the administrator 30 days prior notice of
the performance test. In case of asphalt concrete plants the
precise date may be extremely difficult to pin-point exactly in
43
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time. This is because the plant operates intermittently, not
storing material, but following the needs of field construction.
Many state officials require that tests be run with top or wearing
courses of asphalt concrete, since this type of product has the
largest emission potential. The federal government may also
require this (40 CFR 60.8). It will therefore be necessary to
get an approximate planned date, refining the specific time as
that date draws closer. It would be unusual for a plant operator
to positively specify that exactly thirty days hence he will be
running production of top course in the quantity needed to complete
three tests.
While the date for the performance test is being finalized,
the Enforcement Officer should review any data furnished by the
operator. He should also request the operator to provide the
following items by the time of the performance test:*
1. 3/8" holes, for static pressure determination, in
the ductwork
• before and after the secondary collector
• before and after the fan
2. A suitable hole in the belt guard at fan axis for fan
speed determination
3. A suitable water flow rate meter in the inlet piping
if either
• a wet scrubber secondary collector is used, or
• a gas conditioning system is used in conjunction
with an electrostatic precipitator.
Field Inspections. Field inspections after the performance
test is completed might be made on a routine basis or in response
to complaints. A visit might also be prompted if an enforcement
Officer happening to drive past the plant sees a suspect emission.
It is not necessary for the enforcement officer to give notice
of his visits. A more accurate appraisal of routine operating
procedures is probably afforded from unannounced visits. Deciding
whether to advise the plant of a pending visit or to make an
unannounced visit depends on the judgment of the enforcement officer.
Because of the uncertain nature of the production schedule the
inspector could arrive at a plant to find no production scheduled
for that day, or production in the A.M. when the officer visits in
the P.M., etc. In that instance, production and any malfunction
data could be reviewed, but the operating plant could not be
examined. Asphalt concrete plants located in northern states
often cease production from early January to early March. Plants
will seldom operate when it is raining or if it has rained exten-
sively for several days previously because field conditions are not
conducive to laying the material. Plants most often have their
greatest production in the morning hours, slackening off in late
* The need for these items will be described in Section 8.6
44
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afternoon.
The inspector must decide whether the unannounced visit
advantages outweigh potential ineffective time and potential
inability to make directly relatable comparisons with performance
test data and previous visits.
8.3 Pre-Inspection Preparation -- Data
Performance Tests Monitoring. If the inspection
function is to monitor a performance test the enforcement officer
should obtain this data:
• A copy of the owner's test notification to the
Administrator
• A copy of the owner's permit to construct (obtain
from state)
• A copy of the state's performance test requirements
including emission regulations and methods of per-
forming the tests.
The enforcement officer should then prepare from these
documents as much of the data called for on the Inspection Data
Form for Asphalt Concrete Plants (see page 72) as possible prior
to monitoring the performance test.
Field Inspections. If the purpose of the visit is a field
inspection the enforcement officer should fill in as much data
as is available from the permit application and the performance
tests data on the Inspection Data Form for Asphalt Concrete Plants.
This data will be obtained from:
• Owner's Permits to Construct and Operate (obtain from state)
• Findings from the performance test.
8.4 Pre-Inspection Preparation -- Equipment
The previous section 8.3 dealt with the data that should
be prepared and analyzed prior to a field visit. This section
deals with the equipment which must be taken to the field to
facilitate the inspector's functions.
Safety Equipment. The necessary safety equipment are
hard hats and ear plugs. It may also be advisable to wear safety
shoes and safety glasses. Almost all plants will require hard hats.
It must be remembered that these are small plants and they may not
have extra safety equipment for visitors.
Inspection Equipment. The inspector will have the need
for some equipment in his field visits to asphalt concrete plants.
The equipment is not extensive, but will be necessary for the
proper performance of the job:
45
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• Watch, either stop watch or one with sweep second
hand
• Thermometer, 5" stem or longer, nominally 50-500°F
(10-26QOC)
• Flashlight
0 Tachometer, hand tachometer capable of reading
nominally 100 to 4000 rpm and with two contact
tips, one for center hole and the other for flat
shafts
Camera, a self-developing type
Manometer or differential pressure gage (0-30"H20)
Steel tape, 50 or 100 foot spool
Brush
Plastic bags.
8.5 Initial Procedures for Inspections
Upon arrival at the facility the enforcement officer should
meet with the highest ranking company official at the plant. If
no "ranking official" is present (usually the responsible party
named on the Permit to Construct or Operate) attempts should be
made to notify him by phone of the enforcement officer's presence
and purpose. If the purpose of the visit is a performance test
advance notice will have been made, and the plant and state per-
sonnel will be expecting the visit. If it is an unannounced visit
it will be necessary to present credentials and detail the purpose
and extent of the inspection with the person in charge. If the
person in charge readily agrees with the inspection skip the next
section and proceed to the plant meeting -- monitoring performance
test section which follows. If the person in charge refuses entry
for inspection purposes proceed to the next section.
Refusal of Entry. The right of entry to an emission source
together with the right to examine and copy any required informa-
tion is contained in section 114 of the Clean Air Act.
The reporting requirements are specified in 40 CFR 60.7.
Briefly this section requires reporting of anticipated and actual
start up, a record of startups, shutdowns or malfunction kept
for two years, reports of excess emission submitted to the admini-
strator quarterly and a file of all tests and measurements required
by NSPS regulations. The enforcement officer also has the right
to examine any records required by the state implementation plan.
Should any of these rights be refused, the enforcement
officer should inform the official at the site of the civil
action and injunctive relief that are provided in section 113
of the Clean Air Act (42 USC 1857 et seq.). If the official
persists in his refusal, the enforcement officer should record
his name and the situation, leave the site and forthwith report
the incident to the regional attorney. The enforcement officer
should not take any further action at the site.
46
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Plant Meeting for Performance Tests Monitoring. This
will be a brief informal coordinating meeting with all parties
to the test. The test may be conducted by the state or a private
contractor. Generally the tests will be performed by a private
contractor, and often it will be witnessed by a state official.
The federal inspector should state that he is there to monitor
the tests and that he will do so as unobtrusively as possible.
He should further state that in the event he sees techniques
or equipment used not conforming with the test requirements
set forth in the Standards of Performance for new sources that
he will note same and advise the person in charge of conducting
the test. He should make it clear that he will not interfere
with or preempt any contract arrangement between owner and test
company, but that he will make his observations known and note
them. If the purpose of the visit is to monitor performance
tests the inspector should proceed next to section 8.6 following;
if the purpose is to conduct a field inspection to section 8.7.
8.6 Performance Tests Monitoring
This section will describe in detail the methodology in
gathering key parameters and in observing certain details of the
test procedure during a performance test.
8.6.1 System, Production, and Control Device Parameters
In order to define the "representative conditions" of
the plant operation during a stack test, several parameters
specific to the asphalt concrete process should be measured and
recorded during the stack test by the inspector. Alternatively,
the inspector may require the operator to measure them during a
performance test. There are two reasons for doing this:
1. The set of parametric values will aid in reviewing
the stack test data which will subsequently be
submitted.
2. These values will provide a baseline measure of
the specific operation, and can be used to determine
the extent of changes in operation observed during
subsequent field inspections.
The parameters to be recorded during the stack test and
to be compared, during subsequent field inspections are listed
below. These should be recorded 'on the Parametric Evaluation
Form shown on page 52 of this manual.
SYSTEM PARAMETERS:
1. System Pressure Drop
2. Fan Speed
PRODUCTION PARAMETERS:
3. Cold Feed Size Gradation
4. Percent Surface Moisture
5. Process Weight Rate
47
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CONTROL DEVICE PARAMETERS:
6. Pressure drop across secondary collector
7. Water injection rate (if wet scrubber)
8. Pulse cycle time (if fabric filter)
9. Secondary Power Input (if electrostatic precipitator)
The need for measuring and the method of measuring the
above parameters is described below:
System Pressure Drop. As air moves through a restriction,
such as an elbow in the ductwork, a venturi in a wet scrubber, etc.,
the resistance to the movement of the air is reflected by a drop
in the static pressure of the air, known as pressure drop (A P) •
System pressure drop is the sum of all pressure drops due to the
individual components in the air handling system:
A P System = AP Dryer + AP Ductwork + AP Primary Collector
+ 4? Secondary Collector +AP Damper
Since pressure drop is a measure of the resistance to
air flow, an increase in the system pressure drop results in
a decrease in the air flow rate, if the fan speed is constant.
Thus, if the system pressure drop is increased the capacity of
the system to handle the air flow has decreased and if the air
requirement for the process has not changed, (i.e. by a cor-
responding decrease in the production rate) then a "puff -back"
of dust-laden air may result at the burner end of the dryer.
Also, an increase in the system pressure drop may increase the
static pressure at the point where the main flow and the scavenger
air flow combine, resulting in insufficient handling of scavenger
dust. This may be compensated for by adjustment of the damper,
if one is present.
Since the air handling system is open to atmosphere at both
ends, the system pressure drop is numerically equal to the static
pressure rise in the main fan. It is much easier to measure the
static pressure rise across the fan than to measure all the in-
dividual pressure drops that make up the system pressure drop.
This is not dependent on the location of the fan in the system,
although the fan is generally the last component in the system.
The system pressure drop can therefore be determined
as follows:
1. Select the correct range for the differential
pressure gage (or manometer) .
2. Make the connection between the static pressure
tube at fan inlet and the low pressure end of
the gage (or manometer) as shown in Figure 8-1 (a) ,
with the other (high pressure) end open to atmos-
phere.
48
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FIGURE 8-1
DETERMINATION OF SYSTEM PRESSURE DROP
Detail A
inlet
outlet
fan
high
iW
gage
Pi
(a)
/,' f ~f --^--f. -i J -i -f
*T — . — —
flow direction
AP
Detail A
inlet/ A
outlet
fan
duct
low
•o
gage.
(b)
system
= Pi + Po > inches of water
static pressure tube
'flexible tubing
I
to gage
Detail A
49
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3. The gage static pressure at fan inlet, P-^,
(negative) with reference to the atmospheric
pressure will be registered on the gage (manometer),
in inches of water.
4. Make the connection between the static pressure tap
at fan outlet and the high pressure end of the gage
(or manometer) as shown in Figure (b), with the
other (low pressure) end open to atmosphere.
5. The gage static pressure at fan outlet, PO,
(positive) with reference to the atmospheric pressure
will be registered on the gage (or manometer), in
inches of water.
6. ^"system = static pressure rise across fan
= PI + PO ' inches of water.
This simple procedure is applicable in all cases except
when the air pollution control device is a wet-fan scrubber. In
that case, care should be taken not to entrain water droplets
in the tubing by disconnecting the tubing at the gage and blow-
ing through the tubing to force the droplets out of the pressure
taps immediately prior to taking a reading.
Fan Speed. Fans used to move air in asphalt concrete plants
are positive displacement devices. Thus, the amount of air handled
is directly proportional to the rotational speed of the fan. Any
decrease in the fan speed (such as due to operational wear or
stretch of the belts used in the drive) will result in a decrease
in the air handling capacity of the system, and may cause
"puffback" at the dryer or inefficient collection in the scavenger
system.
The fan speed is determined as follows:
1. Select the proper stem tip attachment for the
tachometer and insert the stem of the tachometer
through a hole in the belt guard (this should be
provided for the purpose of this measurement) at
the axis of rotation of the fan.
2. Press the tip of the tachometer stem against the
center of the fan shaft while the plant is in operation
3. Read the rotational speed of the fan in rpm on the
correct scale after the pointer is steady.
Cold Feed Size Gradation. The stack emissions are related
to the amount of fine particles introduced in the dryer, especially
in the case of inertial control devices such as cyclones and wet
scrubbers. It has been explained in Section 5 that the amount of
fine particles introduced into the dryer varies with the desired
product: for example, wearing or top course will have a greater
50
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amount of fine particles than a binder or a base course. Although
most asphalt concrete plants produce all of the above types of
courses, many states require a production run of top course during
a compliance test (and EPA may require the same condition under
Section 60.8c).
Cold feed size gradation is obtained by first collecting
a representative sample of the cold feed and then subjecting the
dried sample to a sieve analysis. Percent surface moisture can
also be determined from the same sample. The gradation and
moisture tests can be done by an outside laboratory or by a Lab
Technician at the plant in the laboratory usually located at the
site.
A representative sample of the cold feed is best taken
from a conveyor belt at the cold feed end of the dryer in the
following fashion:
1. Observe the flow of different aggregate materials
from the cold feed bins on the conveyor belt while
the plant is operating. For best results, the flow
should be uniform. If the aggregate contains excessive
moisture, or if the surface moisture is frozen, the
aggregate on the belt will be in a non-uniform, lump
form, not directly susceptible to sieve analysis.
2. Coordinate the stoppage of the belt with the plant
operator (he may want to temporarily shut off the
fuel supply during this procedure).
3. Select and mark off a nominal 1-foot length of the
stationary conveyor belt with the cold feed on it.
4. Carefully scoop out the aggregate from the nominal
1-foot length into a plastic bag, taking care to get
the finer particles with a brush, if necessary.
5. Repeat the above process two more times in 15-30
minute intervals, and collect the samples in the
same plastic bag.
6. Seal the plastic bag.
The cold feed sample collected by the above method can
be used to determine the gradation as well as the moisture content.
The inspector may choose to send the sample to an outside labora-
tory with the instructions on the required reporting of the results,
or he may decide to let the plant operator arrange to have the
analysis done at the plant laboratory, perhaps even while the per-
formance test or field inspection is going on.
The size gradation should be reported as shown in the
Form 8-1 entitled Parametric Evaluation Form.
Percent Surface Moisture. The dryer in the asphalt con-
crete plant is used for the purpose of driving surface moisture
51
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FORM 8-1
PARAMETRIC EVALUATION FORM
Company Name
PARAMETER, (units)
DATE
DATE
Location
DATE
DATE
DATE
1. System Pressure
Drop (in. H20
2. Fan Speed (rpm)
3. Cold Feed Size
Gradation:
Cumulative % by weight
passing:
1 1/2"
1"
1/2"
3/8"
MESH # 4
16
32
50
100
200
-------
8-1 (cont'd)
PARAMETRIC EVALUATION FORM
DATE
DATE
.DATE
DATE
DATE
4. Percent Surface
Moisture (%)
5. Process Weight Rate
(tons per hour)
6. Pressure Drop Across
Secondary (in. H-0)
7. Water (Injection CD/
Discharge rj )
Rate, (gpm)
8. Pulse Cycle Time
(Seconds)
9. Secondary Power
Input, (Watts)
Secondary Current (mA)
Secondary Voltage (kV)
10. Other (Specify)
-------
from the aggregate and heating it for better bonding of the
asphalt with the aggregate. Fuel is required to provide the
heat necessary to evaporate the surface moisture. Because the
air handling capacity of the system has a maximum limit, an
increase in the percent surface moisture of the cold feed
reduces the production rate of the plant,,since both the fuel,
through the products of combustion, and surface moisture,
through the water vapor, would increase the air handling
demand at a given production rate. Most dryer manufacturers
rate the dryer capacity at 5% surface moisture. The practical
upper limit on surface moisture is approximately 8%, after
which the aggregate is saturated.
The cold feed sample is taken as described on page 51
and then analyzed for percent surface moisture by drying a known
weight of the sample at about 100°C. The percent surface moisture
is 100 x loss in weight.
dry weight
Process Weight Rate. The amount of fine particles intro-
duced into the dryer is a function of the size gradation as
well as the dryer input rate. Many states have emission regu-
lations based on process weight rate, defined as the sum of all
process input weights divided by the corresponding time duration.
The product of the asphalt concrete plant is monitored as to
weight because the price is based on this weight. Thus there are
three different weight rates associated with the plant:
• Cold feed rate at dryer input, Rc
• Process Weight Rate, R
• Production Rate, Rp
The following diagram shows how these three rates are
related:
hot elevators
st°rage (+ S in 1 hour)
___ asphalt (Al)
cold feed
Let all the rates be expressed in tons per hour. Then:
54
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R /100-M |+ / S I x / 100
V_i
100-A
V
where S is the increase or decrease in the material in
the system (dryer, hot screens, hot bins) in one hour.
In steady state, there will be no appreciable build-up or
drawdown of material in the system, and SR?O. Then:
Rc /100-M ) x / 100 = R
^ 100 J I 100-A / P
Typically, both moisture content M and asphalt percentage
A are = 5%, and the above equation reduces to:
RC = Rp,^ R under the above simplications.
In practice it is a lot simpler to obtain R«, the pro-
duction rate, by the method outlined below. The error made in
determining either R^ or R by measuring R^ and equating the
three rates is approximately +_ 5%, i.e., well within tolerable
limits. The following procedure is used:
1. Make sure the plant has been running for at least
1/2 hour after startup. (Usually, at the end of the
day, the hot bins and the dryer material are completely
emptied). Thus, after startup, material starts
building up in the system. Steady state is reached
after about 1/2 hour's continuous operation, and
S^O).
2. Get the weight of product shipped at the weigh scale
in one hour, or count the number of batches pro-
duced by the plant in one hour if it is a batch
plant. (Knowing the capacity of the pug mill in
tons, the total weight can be calculated).
3. Calculate Rp = Weight of Product
1 Hour
4. Repeat above procedure for one or two more times if
possible.
Pressure Drop Across Secondary Collector. Due to impaction
and agglomeration characteristics of a wet scrubber, efficiency
increases with pressure drop. For a fabric filter, the buildup
of a layer of dust which aids in the filtration process also
creates a resistance which shows up as a pressure drop across
the fabric filter. If the layer becomes too thick the pressure
drop increases and the air flow rate decreases, possibly causing
puffback at the dryer and possible damage to the fabric. On
the other hand, a low pressure drop is indicative of a leak.
For these reasons pressure drop across the collector is an
important parameter. Pressure drop is measured as follows:
55
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FOR SYSTEMS WITH SECONDARY
COLLECTOR UPSTREAM OF FAN
1. Select the correct range
of differential pressure
gage (or manometer) .
2. Make the connection be-
tween the static pressure
tube at the collector in-
let and the low pressure
tap of the gage (or ma-
nometer) as shown in
Figure 8-2 (a), leaving the
high pressure tap open
to the atmosphere.
3. The static pressure, P^
(negative with reference to
atmospheric pressure), can then
be read from the gage (or man-
ometer) in inches of water.
4. Make the connection be-
tween the static pressure
tap at the collector
outlet and the low pressure
tap in the gage (or ma-
nometer) as shown in Figure
8-2 (b) , leaving the high
pressure tap open to the
atmosphere.
5. The static pressure, PQ
(negative with respect
to atmospheric pressure)
can then be read from
the gage (or manometer)
in inches of water.
FOR SYSTEMS WITH SECONDARY
COLLECTOR DOWNSTREAM OF FAN
1. Select the correct range
of differential pressure
gage (or manometer)
2. Make the connection between
the static pressure tube at
the collector inlet and the
high pressure tap of the gage
(or manometer) as shown dotted
in Figure 8-2(a), leaving the low
pressure tap open to the at-
mosphere.
The static pressure, P^ (posi-
tive with reference to atmos-
pheric pressure), can then be
read from the gage (or ma-
nometer) in inches of water.
Make the connection between
the static pressure tap at
the collector outlet and the
high pressure tap on the gage
(or manometer) as shown in
Figure 8-2(b), leaving the
low pressure tap open to
the atmosphere.
The static pressure, PQ (pos-
itive with respect to atmos-
pheric pressure), can then be
read from the gage (or ma-
nometer) in inches of water.
6..AP Collector = Pi - PQ,
inches of water.
6. AP collector = PI - Po
Note: In situations where
there is a short stack
and little ductwork
after the fan the
static pressure at
the collector outlet
will essentially be
zero.
56
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FIGURE 8-2
DETERMINATION OF PRESSURE DROP ACROSS COLLECTOR
Inlet
Detail A
Outlet
Collector
Inlet
High V/_y Low
Gage
(a)
Flow Direction
Duct Wall
Static Pressure
Tube
Flexible Tubin"
To Gage
Detail A
Outlet
Collector
f
I Hih
Detail A
Gage
(b)
(Low
P collector = Pi - Po
57
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If the collector is a wet scrubber care should be
taken to keep the tubing free of any water droplets, as indicated on
page 50.
Water Injection Rate. Water injection rate is related to
the collection efficiency of a wet scrubber. If the water injection
rate goes down, the efficiency is also reduced. Clogged nozzles,
a faulty pump, or leakage could reduce the flow and change the
operating characteristics of the wet scrubber.
Water injection rate can be determined with ease if there
is a water meter in the inlet line to the scrubber. If such a
water meter is not present, the inspector may require the plant
operator to install one (under 40 CFR 60.8e) or he may obtain
a measure of the water flow rate by recording the rate at which
the waste water leaves the scrubber. This can be done by the
method outlined below if the discharge is free -flowing and if
the discharge pipe is horizontal.
horizontal discharge pipe
_ cross-sectional inside area A, ft
discharge
basin
(i) Referring to above diagram, locate a point P which is one
foot vertically below the center line at the end of the
discharge pipe.
(ii) Measure horizontal distance x (in feet) between point P
and the middle of the discharge water jet.
(iii) Calculate the water discharge rate in gallons per minute
by using the formula:
Water Discharge Rate = 1800 k'x , gpm
where x = distance shown above, feet
and A = pipe cross-sectional area, square feet.
The method described above is applicable only if the dis-
charge pipe is horizontal.
Pulse Cycle Time. Fabric filtration mechanism consists
of the build up of a layer of dust on the dirty side of each bag.
As the layer builds up pressure drop increases and, therefore,
the layer is periodically depleted either by mechanical shaking
or by the introduction of a pulse of air. In asphalt plants air
is almost exclusively used. This cyclical process goes on con-
58
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tinuously while the fabric filter is operating. The cycle time is
critical in the sense that if it is too long a large layer is
built up,causing excessive pressure drops at the end of the cycle,
and if it is too short it prevents the filter from operating
over the most efficient part of its build-up cycle.
The pulse cycle time should be read from the setting on
the timer which is either attached directly to the baghouse or
located in the control room near the operator, and the operator
should be able to point it out to the enforcement officer.
Secondary Power Input. The amount of power input to the
electrostatic precipitator is related directly to its operating
efficiency. Thus checking the delivered power to the unit by
reading the secondary current and voltage (power = current x
voltage) is an easy check on the performance of the precipitator:
1. Read the secondary current (in mA) and voltage
(in kV) from the meters, which are usually located
near the transformer section of the precipitator.
2. Secondary power input = current x voltage (in watts)
Summary. The above are key parameters which establish pro-
duction rates and operating conditions for future comparisons.
The Parametric Evaluation Form should be used to record information
gathered above.
As will be shown in Section 8.7.1 there are ranges of
the above parameters which can be used as a guide to determine
whether the process, including the control devices, as observed
during a field inspection, has significantly changed from its
operation during which the performance test was taken. Changes
in some of these parameters may suggest malfunctions that should
be brought to the attention of the plant operator and may call
for another performance test.
8.6.2. Observation of a Performance Test
The use of EPA approved methods for performance testing of
particulate matter is required by 40 CFR 60.8 and 40 CFR. 60.11. Specific
test requirements of asphalt concrete plants are listed in 40 CFR 60.93.
General procedures describing EPA-approved methods for stack testing
and the witnessing by a federal Enforcement Officer of stack tests
are covered in detail in "Emission Testing Compliance Manual" pre-
pared by Pedco Environmental Specialists, Inc. for EPA. The inspec-
tor should familarize himself with this manual, especially chapters
1 and 2.
The enforcement officer, while monitoring a stack test on
an asphalt concrete plant, should limit his observations to a few major
items. The data should be recorded on Form 8-2 entitled, Performance
Test Observation Form. The following numbered paragraphs refer
to data identification numbers on the form.
59
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Cross-sectional dimensions of the flow duct at
the sampling location should be recorded (both
inside and outside).
Number of sampling points to be chosen for the
stack sampling depends upon where the nearest
upstream and downstream obstructions (such as an
elbow, a change in the flow area, end of the stack,
etc.) are located. Check with the crew leader on
the total number of points to be traversed, and
compare it to Figure 1.1, 40 CFR 60, Appendix A,
to determine whether the flow will be properly
sampled.
In many cases an assumption of the moisture content
is acceptable, based on the prior experience of the
sampling crew on other asphalt concrete plants. If
the crew is in doubt, then check to insure that
the moisture content of the gas (for nomograph
setting) is determined using method 4.
Note the inside diameter of the nozzle the testing
crew selected for sampling.
Immediately prior to starting each run, the crew
must test the assembled sampling train for leaks.
Observe the following points during this leak test:
a. The vacuum gage in the sampling circuit should
register a steady reading of 15 inches of
mercury during the leak test.
b. The leakage rate is determined by observing
the movement of the dry gas meter in one
minute (a stopwatch should be used for this
purpose).
c. The leakage rate at 15 in. Hg vacuum should not
be greater than 0.02 cfm (the maximum limit
set forth in Method 5).
Because of the high vacuum created through the
sampling train while leak testing, there is a
possibility of some of the water in one of the
impingers being sucked into the next impinger.
For this reason, the leak test duration is
usually kept to the minimum.
Observe the impingers containing water during the
course of sampling. If no bubbles are seen the
sampling train is either disconnected from the pump
or plugged.
Observe the gas analysis procedure (methods). At
least three samples should be analyzed before averaging
readings for the purpose of determining the dry
molecular weight of these gases. (Because of the high
excess air combustion practiced in asphalt plants,
the dry molecular weight is usually 29. Deviations
in the molecular weight of more than 5% indicate a
significantly different combustion process than is
normal in asphalt concrete plants).
60
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Observe the method of cleaning and sample recovery
between runs. Careless removal of filters,or inadequate
cleaning of probes will result in a loss of collected
particulate matter for emission calculation purposes.
Determine approximately when the following parts
of the sampling train were last calibrated, or measured.
Pitot tube
Thermocouple/thermometer
Dry gas meter
Orifice diameter
Nozzle diameter.
When the emission testing firm submits a test report the
results should be carefully checked and compared with the data
recorded by the inspector for points 1-9 above. Thus, the Per-
formance Test Observation Form provides both a verification of
proper test procedures as well as baseline data for the acceptance
of stack test results.
8.7 Field Inspections
The previous section dealt with performance test
monitoring. This section deals with field inspections.
Once plant entry for inspection purposes is assured and
access to documents is gained the inspector should proceed with
examination of the records and a briefing of the official in
charge. The inspector should review the operating conditions
and shutdown procedures. Copies of applicable regulations should
be briefly reviewed and given to the official in charge if
he does not have copies. The inspector should also review any
logs, recording charts and records of operation with the plant
foreman to determine any changes from the last visit in operating
procedures the control process or other factors that could
influence emissions. This will also help the inspector determine
"normal operating procedures" so that he can recognize any abnormal
or changing conditions. A brief itinerary of the visit should be
outlined. At this point the official in charge can outline his
production for the next several hours so the inspector can best
schedule his duties. When he knows the plant conditions and
production type and quantity of material the inspector is in a
position to proceed with the inspection.
8.7.1 Plant Inspections
Plant inspections will essentially involve three areas of
activity:
1. Opacity Readings
2. Acquisition of key plant data
3. An evaluation of plant maintenance and operational
characteristics.
61
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FORM 8-2
PERFORMANCE TEST OBSERVATION FORM
Company Name: Date:
Plant Identification and Address: Performance Test By:
Plant Official: Crew Leader:
1) Cross-sectional duct dimensions at sampling location
(i) inside circular Q } rectangular O
(ii) outside
2.1) Flow obstructions
(a) upstream from the sampling location
(b) downstream from the sampling location
2.2) Total no. of sampling points chosen
3) Moisture content
Q assumed
Q method 4
4) Inside nozzle diameter
5) Leak test
(i) Vacuum gage reading in Hg
(ii) Dry gas meter reading cf in sec
6) Impinger bubbles, yes no_
7) Gas Analysis Procedure No. of samples analyzed
8) Cleaning and Sample Recovery, Adequate Careless
9) Calibration check Date calibrated
(i) pitot tube
(ii) thermometer/thermocouple
(iii) dry gas meter
(iv) orifice diameter
(v) nozzle diameter
62
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Opacity Readings. The inspector should conduct opacity
readings of the main stack and any fugitive sources he observes
from the cold aggregate input to the terminus of the system.
The number of readings and the technique of taking the readings
shall be as specified in Method 9. Form 8-3 a and b are the
recommended forms for recording a visual determination of opacity.
A synopsis of this data is to be recorded as data item 8 on
the Inspection Data Form for Asphalt concrete Plants, Form 8-4
at the end of this section.
Acquisition of Key Plant Data. This is the same type
of data as recorded on Parametric Evaluation Form described in
detail in Section 8.6. The purpose of again gathering this data
is to compare the system operation at this point in time against
that of the performance test or previous field inspection.
Because of the innumerable process and material variations
possible it would be impossible to fully describe all the changes
that could result in a previously acceptable facility being out
of compliance. It is,however, possible to outline the extent and
direction of certain key changes which are significant, that
should indicate to the inspector that the source may no longer
be in compliance. If further inspection does not satisfactorily
explain the change in operating conditions the inspector could
require another stack test at the conditions then prevailing.
The following list will serve as a guide along these lines.
1. System Pressure Drop: Change significant if
observed change^ 20% in either direction.
2. Fan Speed: Change significant if observed decrease
is -^ 20%.
3. Cold Feed Size Gradation: This defines the material
being produced. If the gradation during a field
inspection shows that a much finer aggregate is
being produced than during the stack test (an
increase of 50% or more of -200 mesh) it may indicate
that the performance test was not run under the
proper conditions.
4£5. Process Weight and Percent Surface Moisture: Change
significant if observed increase in Process Weight
Rate at the same moisture content as observed during
the performance test isx*20%. (For other moisture
contents the inspector should use his discretion,
keeping in mind that the process weight rate drops
by approximately 10% for every 1% increase in
surface moisture).
6. Pressure Drop Across Secondary Collector:
a. Wet Scrubber: Change is significant if observed
decrease is ^-10%.
b. Fabric Filter: Change is significant if:
1. Observed decrease is/7" 20% (indicative of
a leak)
2. Observed increase is/" 20% (indicative of
cake build-up change)
63
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FORM 8-3 a
OBSERVATION RECORD
COMPANY
LOCATION
TEST NUMBER
DATE
OBSERVER
TYPE FACILITY
POINT OF EMISSIONS
ON
JJJLt_
zz
Min.
0
1
2
3
4
C,
6
7
8
1 i
10
fi
12
13
14
15
IT
1—
i —
—
~
Se
~rr
16 |
>7 1
18
19
20
21
22
21
.. 24
25
26
27
20
29
„_.
_.
1
|
!
f
1
conds
rrrr^rr
t
STEAM PLUME
(check if applicable)
Attached
Detached
COMMENTS
COMPANY
LOCATION"
TEST NUMBER
DATE
OBSERVER
TYPE FACILITY '
POINT OF EMISSIONS
Hr.
Min.
30
31
32
33
34
35
i 36
37
38
39"1
40
41
42
43
44
45
46
47
r~48
49
50
51
52
53
54
55
56
57
sa
59
Seconds
0
IS
30
45
STEAM PLUME
(check if applicable)
Attached
Detached
COMMENTS
-------
COMPANY
LOCATION
TEST NUMBER
DATE
TYPE FACILITY
CONTROL DEVICE
FORM 8-3 b
RECORD OF VISUAL DETERMINATION OF OPACITY
HOURS OF OBSERVATION,
OBSERVER
OBSERVER CERTIFICATION DATE_
OBSERVER AFFILIATION
POINT OF EMISSIONS
HEIGHT OF DISCHARGE POINT
on
CLOCK TIME
OBSERVER LOCATION
Distance to Discharge
'Direction from Discharge
Height of Observation Point
BACKGROUND DESCRIPTION
WEATHER CONDITIONS
Wind Direction
Wind Speed
Ambient Temperature
SKY CONDITIONS (clear,
overcast, % clouds, etc.)
PLUM' DESCRIPTION
Color
Distance Visible
CTIiCR IMFOOTIOIl
Initial
Final
R
1
t
SUMMARY OF AVERAGE OPACITY
Set
Number
.. - Time....
Start—End
Opacitj
Sum
Average
eadlngs ranged from to % opacity
he source was /was not 1n compliance with .at
he time evaluation v/as made.
-------
7. Water Injection Rate: Change is significant if
observed decrease is 7 20%.
8. Pulse Cycle Time: Change is significant if observed
decrease is "750%.
9. Secondary Power (Electrostatic Precipitator) significant
if the power decreased by 7 20%.
It is estimated that an inspector who has experience in
inspecting asphalt concrete plants can gather the data in steps
1-9, except the cold feed gradation in step 3 above, in one hour
if the plant is running, and make the comparison with previous
data in fifteen minutes. They should be summarized in data item 6.
The next step in the inspection procedure is to evaluate
plant maintenance and operation practices. Data obtained here
should be recorded in data items 7 and 8 on the Inspection Data
Form for Asphalt Concrete Plants.
Maintenance and Operational Practices. This section involves
the inspection of the various components that make up the system
for proper maintenance and operational practices. Poor practices
result in fugitive dust and improper functioning.
Dryer and Burner. The function of the dryer is to heat
the aggregate to between 250° and 375°F.
The inspector should record the dryer outlet temperature.
There is generally a gage in the control room monitoring that
temperature.
The balance between the combustion air (draft) and rate
of fuel fired is very important and can affect emissions significantly.
Improper combustion balance may cause incomplete combustion and
subsequent emission of black smoke.
The inspector should check for this imbalance. Indications
are a smoky flame in the dryer or a symptom called "puff back".
Puff back occurs when the draft created by the fan (or blower)
is not sufficient to accommodate the air pressure being introduced
by the burner blower and some fugitive dust is blown out around
the dryer inlet.
This causes serious dust and smoke emissions at the dryer,
probably in excess of opacity regulations. Puff back can be remedied
either by increasing primary draft air or decreasing fuel firing
rates.
The opposite case where there is an excess of draft
for the fuel firing rate can also occur, leading to underheated
aggregate and increased hydrocarbon emissions. This cannot be
determined by the inspector.
66
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Proper plant operations call for the operator to reduce
the draft (close the damper) until puff-back appears, and then
gradually increase draft until puff-back is eliminated. This
procedure not only is a good system balance, but it is an excel-
lent method of conserving energy. Proper practice, however, requires
that the damper be readjusted each time the feed rate, moisture
content, or burner setting is changed.
In conducting this part of the inspection the inspector
should wear hearing protection as the noise level close to the
burner is high.
Mixing Tower. After the dryer the heated aggregate is
generally transported via bucket elevator to the mixing tower. The
inspector should check the hot elevator and all points in the tower
where fugitive emissions could result. This includes physical
inspection of all system components for leaks, bad seals in duct-
work, and general condition. Specific points to check are the
hot screens, bins, weigh hopper, pugmill and rock reject chute
(designed to discharge overflow or oversize from the screens).
Notes should be taken or sketches made of the fugitive
(scavenger) system if not available from performance test reports.
Opacity regulations apply to all of the points on the fugitive
system and batch tower. (See data item 8)
8.7.2 Control Device Inspection
Control device inspection begins with dryer exhaust duct
and scavenger system ductwork and ends at the stack outlet.
All ducts leading to the primary control device or to what-
ever control is used in the absence of a primary should be checked
for leaks, rust and general condition. A sketch and description
of the control layout may prove valuable at a later date if not
contained in the Performance Test Record. (See data item 8)
Primary Control. The most common primary control system
is a cyclone. The cyclone may be single or multiple unit (usually
single) .
The cyclone should first be checked for leaks and general
condition. The routing of collected material should be noted and
if necessary a sketch drawn. (See data item 8)
The pressure drop across the cyclone should also be deter-
mined if leaks are evident and compared with previous data if
available.
Secondary Control. As discussed earlier the only controls
likely to be encountered as final controls are baghouses, venturi
scrubbers, two or more wet scrubbers in series, and to a lesser
degree, electrostatic precipitators.
67
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Generally they should be inspected for physical condition
and any leaks. The final control device should be included in any
sketches and photographs made.
Fabric filters are becoming increasingly popular in con-
trolling particulate emissions from asphalt plants and will prob-
ably be on the bulk of plants inspected.
The inspector should determine the design air to cloth
ratio and also that of the normal flow at the facility or on-
line air to cloth ratio. Information for this should be on the
plant's operating permit Performance Test.
Pressure drop across the baghouse is also important for
the inspector to determine. Often plants will have a gage or
manometer permanently installed in the system to monitor pres-
sure drop.
The type and frequency of the cleaning mechanism should
be noted. To determine the cleaning cycle it is best to locate
the timer and check the setting with the plant foreman.
Usually an inspection of the interior of the baghouse is
not necessary, however, if puffs of dust or opacity problems are
noted in the course of the inspection the enforcement officer may
elect to inspect the interior of the baghouse. Bag compartment
access doors or inspection door can be used for this purpose.
The enforcement officer should look for dust in the clean plenum.
In top opening baghouse compartments there may be actual dust
rings on the compartment cover directly above the faulty bag
or surrounding the open section of the bag where it pierces the
plenum separator. This indicates leakage.
Wet scrubber efficiency is primarily dependant on pres-
sure drop and water injection rates. These parameters should be
recorded for all wet collectors.
Water injection rates are often monitored by gages in the
line,and these readings should be recorded. The inspector should
also note the disposal procedure for the scrubber effluent, es-
pecially whether or not water is recycled. If so, the visual
condition of the water before it is reused should be noted (if
it is muddy, oil streaked, odorous etc.).
Many venturies have adjustable throats (variable venturi
restrictions). If this is the case note the position of the
control setting and compare it to the conditions noted during pre-
vious Inspections or during the performing tests.
Electrostatic precipitators are not commonly found on
asphalt plants. However,they can achieve the necessary efficiencies,
The enforcement officer should locate and record the
readings of both the voltage and current to the plates of the
68
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precipitator. These meters are on all electrostatic precipitators.
In applications to asphalt plants electrostatic preci-
pitators may require gas pre-conditioning to attain proper par-
ticle resistivity. Such preconditioning generally involves hu-
midity control. If a gas conditioning device is present the in-
spector should note whether it is operating and the liquid flow
rate.
A sketch or photo and notes on the layout of the elec-
trostatic precipitator and ancillary devices may be helpful.
Fan or blower. The blower is important to both the
process and control of emissions from asphalt plants.
Its inspection should include obtaining nameplate data,
checking its general condition and using a tachometer to measure
the r.p.m. Determining the static pressure drop across the fan
is important.
The temperature of the exhaust gas should be recorded
at the stack at a convenient point as close to the stack as
possible.
8.7.3 Scavenger Systems
The scavenger system usually consists of pick up hoods
and ductwork from the hot screens, pugmill and weigh hopper area
and from the hot elevator. These generally are two or three ducts
which merge and are then carried to the primary collector. Fu-
gitive dust at any of these points isan indication that the scav-
enger system is not functioning properly. This can be attributable
to poor design where flow rates and fan capacity were not properly
engineered, leaks, or stoppages in the scavenger ductwork caused
by insufficient maintenance of the system.
8.7.4 Materials Handling Systems
Many plants, using controls that collect material in a
dry form, have storage silos to store recovered material either
for future use in the plant or as a salable product.
These systems generally involve taking the collected
material from the control device (usually a baghouse) and pneu-
matically conveying it to storage silos mounted so that trucks
can pull under them for loading. Inspection of these systems
should involve a check for system leaks and general condition.
As material is conveyed to the silo, the air displaced
by the material and the air introduced by the pneumatic system
must be vented. These vents should be controlled either with a
small fabric filter on the vent or by routing the displaced air
69
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back to the control system. Collected materials are often loaded
into a truck from the silo or control device. These sources are
also subject to opacity regulations.
8.8 Startup, Shutdown, Malfunction
The enforcement officer should be aware of all the report-
ing requirements regarding startups, shutdowns and malfunctions.
This includes SIP as well as NSPS requirements.
NSPS regulations require the operator to maintain records
of startups and shutdowns or malfunctions for a period of two years.
Additionally, if the startups, shutdowns or malfunction result
in emissions in excess of normal rates the operator must report
these emissions quarterly as described in the NSPS regulations
(40 CFR 60.7). As prescribed in the regulations, opacity standards
and concentration standards do not apply during periods of start-
up, shutdown or malfunction.
Due to the operational nature of asphalt plants, start-
ups and shutdowns are common occurrences. Proper operating
procedures during these times will minimize any excess emissions
that may result. Some things that the inspector should check
for are: that the air in the control equipment is permitted to
warm up sufficiently before production is started - this is vital
for baghouses; and that the blower or fan is always running be-
fore the burner is fired and after the cold feed or burner and
dryer are turned off.
Malfunction as defined in the NSPS regulation means "any
sudden and unavoidable failure of air pollution control equipment
or process equipment or of a process to operate in a normal or
usual manner. Failures that are caused entirely or in part by
poor maintenance, careless operation, or any other preventable
equipment breakdown shall not be considered malfunctions".
(40 CFR 60.2)
Because of the series connection of components of produc-
tion in asphalt plants, most process malfunctions will necessitate
shutdown.
Control malfunctions then will be of most interest to the
inspector. Should a malfunction be discovered or claimed at any
point during the inspection, the inspector should record its
nature and cause (if possible). The inspector should try to
determine whether the malfunction is unavoidable or preventable
in light of the definition set forth in the regulations. If pre-
ventable the violation, if one exists, should be recorded. Main-
tenance records, receipts, purchase orders for replacement parts,
etc. should be reviewed to assist in the evaluation of the mal-,
function. In the case of an unavoidable malfunction the inspector
should check on the corrective measures that will be taken to
70
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prevent a repetition.
Finally, a follow up inspection is recommended to see
that the malfunction is remedied in a reasonable amount of time.
This inspection need be concerned only with the malfunction, un-
less some other significant event happens.
71
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FORM 8-4
INSPECTION DATA FORM FOR ASPHALT CONCRETE PLANTS
Data Item 1: Location Information
Coup any Name § Address
Plant Identification § Location
Company Official § Phone No.
Plant Official § Phone No.
Data Item 2: Reason for Inspection
Q Routine
d In response to complaint :
O Suspected violation
(check one or more)
Complainant
Date of Complaint
Data Item 5: State/Local Agency Action
Data Item 4: General Plant Data
Type Plant: New CD, Modified 1~1
Type Plant: Continuous CD , Batch ED , Portable d} , Permanent CD
Production: Rated Capacity at 51 surface moisture ton/hr.,
Normal Rate ton/hr.
72
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INSPECTION DATA FORM (cont'd)
Annual Production: tons
Type Fuel: Gas CD , Oil Q , Grade of Oil
Fuel Consumption: Gas cu.ft./hr. Oil gal./hr.
Raw Materials:
(1) Aggregate Source
(2) Maximum %-#200 mesh (wearing course)
Date of sieve analysis
(3) Asphalt Consumption gal./yr. Grade
Supplier Storage Temp.
Nearest Building or Structure Off the Plant Site:
Approximate distance from exhaust stack
Use: Industrial f"l , Commercial n , Residential r~~i
Normal Operating Schedule: Permanent Plants
1. hrs./day days/wk. weeks/yr.
2. I of Total Annual Production: Jan.-May
May-Aug. Sept. -Oct. Nov. -Dec.
Normal Operating Schedule: Portable Plants
1. Start Date End Date
2. hrs. /day days /wk.
Data Item 5: Performance Test Abstract
Date of Last Source Test No. of Runs
Test Performed by _______^___
Particulate Emissions gr./dscf Ibs./hr.
Visual Emissions During Test: % Opacity
73
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INSPECTION DATA FORM (cont'd)
%-#200 Mesh in Dryer Feed During Test
Production Rate During Test
Data Item 6: System, Production § Control Device Paran
(Summarize information from Parametric Evaluation Form
1) System Pressure Drop in P^O
2) Fan Speed rpm
3) Cold Feed Size Gradation
Percent by weight passing #200 mesh %
4) Percent Surface Moisture %
5) Process Weight Rate tph
6) Pressure Drop Across Secondary H70
7) Water (injection a/ discharge o) Rate gpm
8) Pulse Cycle Time sec.
9) Secondary Power Input w.
_10) Other: specify
(* Identify any significant changes in Parameters here,
reported or observed: see Section 8.8.2 for details]
Data Item 7: Field Inspection Data
1) Dryer: Manufacturer § Model No.
Size - diameter ft., length
Type of exhaust outlet - end Q ,
2) Burner: No. of burners - one CD , two O
Manufacturer § Model No.
Fuel used
leters
here)
Previous
Reading
-
if
ft.
center C
Signifi-
cant
Change*
3
74
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INSPECTION DATA FORM (cont'd)
3) Pugmill:
4) Storage
Silo:
Batch size Ibs./batch
Batch cycle time sec.
Controlled by scavenger
(aggregate, mineral filler) type
Controlled by scavenger
5) Primary
Collector: type
_
Manufacturer § Model No.
6) Secondary
Collector: type
Manufacturer § Model No.
7) Scavenger
System: areas controlled
Hot elevator
Hot bins
Pugmill
Mineral filler]
system
screens
weigh hopper
storage silo
If scavenger system has separate controls, give details:
8) Fan § Motor:
Fan: Manufacturer § Model No.
Motor: Manufacturer § Model No.
rated horsepower
rated speed
rpm
Data Item 8: Maintenance § Operational Practices
1) Dryer § Burner
dryer outlet temperature
puffback |__J
smoky flame |[
oF
75
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INSPECTION DATA FORM (cont'd)
2) Mixing Tower
fugitive emissions CD opacity
source/s:
scavenger ductwork (sketch)
3) Control Device
a. dryer exhaust ductwork:
leaks
rust czi
general condition: good EZ3 , poor f~~|
b. primary control device:
leaks c=J
rust r— [
general condition: good ED , poor CD
(sketch)
c. secondary control device (fabric filter):
air-to-cloth ratio: design , actual
pressure drop in hLO
pulse cycle time sec.
disposal of collected dust
d. secondary control device (wet scrubber):
water (injection II /discharge I I ) rate
waste disposal procedure
color: , oil CU , odor
throat control setting (if venturi)
pressure drop in FLO
76
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INSPECTION DATA FORMS (cont'd)
e. secondary controldevice (electrostatic precipitator)
gas conditioning
liquid injection rate gpm
disposal of collected dust
4) Fan or Blower
static pressure rise in H-O
fan speed rpm
general condition: good i—| , poor i—]
5) Materials Handling System
leaks
general condition: good nu , poor r—i
vent line: controlled I~~l , uncontrolled f—i
vent line opacity
6) Stack Plume Opacity
Data Item 9: Administrative Action Checklist
(This space may be used to list any administrative action)
77
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SECTION 9
POST-INSPECTION ACTION
The inspector's findings during his inspection of the plant
should be briefly conveyed to the plant official at the site
before leaving the premises. Specific violation decisions should
neither be made nor discussed in the field.
The inspector should, within 48 hours after the inspec-
tion, complete his report on the inspection. This report will
consist of updated forms and recommended action and should be
forwarded to the supervisor.
Decisions for subsequent action should be made in a con-
ference with the supervisor. If the inspection revealed that the
plant was operating normally and if the decision requires no fur-
ther action, then the report should be filed in the source file
for future reference.
If the inspection revealed a significant change in plant
operation and if the decision is to require a new performance
test, the plant official should be so informed in writing.
If the inspection revealed a violation of the opacity
standard then the decision may be to issue an order requiring
compliance with the standard.
If the inspection revealed a violation of the opacity
standard and if the plant official has claimed an unavoidable mal-
function as a reason, then the decision should be to remind the
plant operator of the recordkeeping requirements of 40 CFR 60.7,
and followup inspection should be planned, prior to any other action.
79
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APPENDIX
PART 60-STANDARDS OF PER-
FORMANCE FOR NEW STATION-
ARYSOURCES
Subpart A — General Provisions
§ 60.1 Applicability.
Except as provided In Subparts B and
C, the provisions of this part apply to
the owner or operator of any stationary
source which contains an affected facil-.
ity, the construction or modification of!
which is .commenced after the date of,
publication in this part of any standard,
(or, if earlier, the date of publication of'
any proposed standard') applicable to
that facility.
[39 FR 20790, June 14, 1974]
[40 FR 46250, October 6, 1975]
§ 60.2 Definitions.
As used in tiiis part, all terms not
defined herein shall have the meaning
given them in the Act:
(a) "Act" means the Clean Air Act
(42 U.S.C. 1857 et se<3., as amended by
Public Law 91-604, 84 Stat. 1676).
(b) "Administrator" means the Ad-
ministrator of the Environmental Pro-
tection Agency or his authorized repre-
sentative.
(c) "Standard" means a standard of
performance proposed or promulgated
under this pan.
(d) "Stationary source" means any
building, structure, facility, or installa-
tion which emits or may emit any "air
pollutant and which contains any one or
combination of tie following:
(1) Affected.f abilities.
(2) Existing facilities.
(3) Facilities of the type for which no
standards have been promulgated in this
part.
[40 FR 58415, December 16, 1975]
(e; "Affected facility" means, with
reference to a s'uiv.onary source, any ap-
paratus to which =. standard is applicable.
(f) "Owner or operator" means anj
person who owns, leases, operates, con-
trols, or supcrv-i_=rs an affected facility
or a stationary source of which an af-
fected facility is a part.
(g) "Construction" means fabrication.
erection, or irtsis_!ation of an affected
facility.
(h) "Modification!.' means any physi-
cal fhagige In, or ciiange-Jh. the. method
of operation of, ar. existing facility- which
increases tUe^mi&iiDt of &ny tux-pollutant
(to which .a ;*tac.darcL;*ppIjea)., emitted
into the- atmosphere -bjt thai facility or
W&ich results in trte-&tqissum of-any air
goliutant 1) "Standard conditions" means a
tf.aiperature of 20 JC (68°F) .and a pres-
sure of 7GO mm of Hg (29.92 in, of Hg>.
(m> "Proportional sampling" means
sampling at a rate that produces a con-
stant ratio of sampling rate to stack gas
flow rate.
(n) "Isokinetic sampling" means
sampling in "Mulf unction" means any sudden
and unavoidable failure of air pollution
control equipment or process equipment
or of a process to operate in a normal
or usunl manner Failures that are caused
entirely or in part by poor maintenance,
careless operation, or any other prevent-
able upset condition or preventable
equipment breakdown shall not be con-
sidered malfunctions.
(ri "One-hour period" means any.60
minute period . commencing on the
hour.
[40 FR 46250, October 6, 1975]
(s) "Reference method" means any
method of sampling and analyzing for
an air pollutant as described in Ap-
pendix A to this part.
[39 FR 20790, June 14, 1974]
«t> "Equivalent method" means any
method of sampling and analyzing for an
air pollutant which have been demon-
strated to the Administrator's satisfac-
tion to have a consistent and quantita-
tively known relationship to the refer-
ence method, under specified conditions.
tu> "Alternative method" means any
method of sampling and analyzing for an
air pollutant which is not a reference or
equivalent method but which has been
demonstrated to the Administrator's sat-
isfaction to, in specific cases, produce
results adequate for his determination of
compliance.
(v) "Particulate matter" means any
finely divided solid or liquid material,
other than uncombined water, as meas-
ured by Method 5 of Appendix A to this
part or an equivalent or alternative
method.
[39 FR 20790, June 14, 1974]
(w) "Run" means the net period of
time during which an emission sample
is collected. Unless otherwise specified,
a run may be either intermittent or con-
tinuous within the limits of good engi-
neering practice.
•(x) "Six-minute period" means any
one of the 10 equal parts of a one-hour
period.
(y) "Continuous monitoring system"
means the total equipment, required
under the emission monitoring sections
in applicable subparts, used to sample
and condition (if applicable), to analyze,
and to provide a permanent record of
emissions or process parameters.
(z) "Monitoring device" means the
total equipment, required under the
monitoring of operations sections in ap-
plicable subparts, used to measure and
record (if applicable) 'process param-
eters.
[40 FR 46250, October 6, 1975]
(aa) "Existing facility" means, with
reference to a stationary source, any ap-
paratus of the t-pe for which a standard
is promulgated in this part, and the con-
struction or modification of which was
commenced before the date of proposal
of that standard; or any apparatus
which could bs alterei ir. such a way as
to be of that tvpe.
(bb) "Capital expenditure" means an
expenditure for a physical or operational
change to an existing facility which ex-
ceeds the product of the applicable "an-
nual asset guideline repair allowance
psrcentage" specified in the latest edi-
tion of Internal Revenue Service Publi-
cation 534 and the existing facility's
basis, as defined bv section 1012 of the
Internal Revenue Code.
[40 FR 58415, December 16, 1975)
[40 FR 58415. December 16, 19751
-------
APPENDIX
PART 60-STANDARDS OF PER-
FORMANCE FOR NEW STATION-
ARYSOURCES
Subpart A—General Provisions
§ 60.1 Applicability.
Except as provided In Subparts B and
C, the provisions of this part apply to
the owner or operator of any stationary
source which contains an affected facil-.
ity, the construction or modification of!
which Is .commenced after the date o£
publication in this part of any standard,
(or, if earlier-, the date of publication of'
any proposed standard') applicable to
that facility.
[39 FR 20790, June 14, 1974]
[40 FR 46250, October 6, 1975]
§ 60.2 Definitions.
As used in tivis part, all terms not
defined herein shall have the meaning
given them in the Act:
(a) "Act" means the Clean Air Act
(42 U.S.C. 1857 et sect., as amended by
Public Law 91-604, 84 Stat. 1676).
(b) "Administrator" means the Ad-
ministrator of the Environmental Pro-
tection Agency or his authorized repre-
sentative.
(c) "Standard" means a standard of
performance proposed or promulgated
under this pan.
(d) "Stationary source" means any
building, structure, facility, or installa-
tion which emits or may emit any "air
pollutant and which contains any one or
combination of tie following:
(1) Affected.facuities.
(2) Existing facilities.
(3) Facilities of the type for which no
standards have been promulgated In this
part.
[40 FR 58415, December 16, 1975]
(e> "Affected facility" means, with
reference to a stcv.onary source, any ap-
paratus to which ^ standard is applicable.
(f) "Owner or operator" means anj
person who owns, leases, operates, con-
trols, or supervises an affected facility
or a stationary source of which an af-
fected facility is a part.
(g) "Construction" means fabrication.
erection, or insisJation of an affected
facility.
(h) "Modification" means any physi-
cal ciiang* In, or change-Jh. the. method
of operation of, ar. existing facility-which
irycr^asfts t^*° arn^iinf of any tux-pollutant
(to which .a; s&ndarcL;qppIfe9)..,- emitted
tatp the-atmosphere-fast "thai facility or
W&ich results in trte-&tqiss"m of-any sir
goliutant (to whi^y a standard appliesD
fcrto , tha• atmoopaer* 'pai- -previously
e«nitt«d-. -'-"'
[40 FR 58415. December 16, 19751
(ii "Commenced" means, with respect
to the definition of "new source" in sec-
tion lll(a) (2) of the Act, that an owner
or operator has undertaken a continuous
program of construction or modification
or that an owner or operator has entered
into a contractual obligation to under-
take and complete, within a reasonable
time, a continuous program of construc-
tion or modification.
(j) "Opacity" means the degree to
which emissions reduce the transmission
of light and obscure the view of an object
in the background.
(k) "Nitrogen oxides" means all ox-
ides of nitrogen except nitrous oxide, as
measured by test methods set forth in
this part.
>1) "Standard conditions" means a
temperature of 20 JC (68°F) .and a pres-
sure of 7GO mm of Hg (29.92 in, of Hg).
(m) "Proportional sampling" means
sampling at a rate that produces a con-
stant ratio of sampling rate to stack gas
flow rate.
(n) "Isokinetic sampling" means
sampling in which the linear velocity of
the gas entering the sampling nozzle is
equal to that of the undisturbed gas
stream at the sample point.
(o) "Startup" means the setting in
operation of an affected facility for any
purpose.
ip> "Shutdown" means the cessation
of operation of an affected facility for
any purpose.
iq> "Malfunction" means any sudden
and unavoidable failure of air pollution
control equipment or process equipment
or of a process to operate in a normal
or msuol manner Failures that are caused
entirely or in part by poor maintenance,
careless operation, or any other prevent-
able upset condition or preventable
equipment breakdown shall not be con-
sidered malfunctions.
(ri "One-hour period" means any.60
minute period . commencing on the
hour.
[40 FR 46250, October 6, 1975]
(s) "Reference method" means any
method of sampling and analyzing for
an air pollutant as described in Ap-
pendix A to this part.
[39 FR 20790, June 14, 1974]
(t> "Equivalent method" means an}'
method of sampling and analyzing for an
air pollutant which have been demon-
strated to the Administrator's satisfac-
tion to have a consistent and quantita-
tively known relationship to the refer-
ence method, under specified conditions.
tu> "Alternative method" means any
method of sampling and analyzing for an
air pollutant which is not a reference or
equivalent method but which has been
demonstrated to the Administrator's sat-
isfaction to, in specific cases, produce
results adequate for his determination of
compliance.
(v) "Particulate matter" means any
finely divided solid or liquid material,
other than uncombined water, as meas-
ured by Method 5 of Appendix A to this
part or an equivalent or alternative
method.
[39 FR 20790, June 14, 1974]
(w) "Run" means the net period of
time during which an emission sample
is collected. Unless otherwise specified,
a run may be either intermittent or con-
tinuous within the limits of good engi-
neering practice.
•(x> "Six-minute period" means any
one of the 10 equal parts of a one-hour
period.
(y) "Continuous monitoring system"
means the total equipment, required
under the emission monitoring sections
in applicable subparts, used to sample
and condition (if applicable), to analyze,
and to provide a permanent record of
emissions or process parameters.
(z) "Monitoring device" means the
total equipment, required under the
monitoring of operations sections in ap-
plicable subparts, used to measure and
record (if applicable) 'process param-
eters.
[40 FR 46250, October 6, 1975]
(aa) "Existing facility" means, with
reference to a stationary source, any ap-
paratus of the t-pe for which a standard
is promulgated in this part, and the con-
struction or modification of which was
commenced before the date of proposal
of that standard; or any apparatus
which could bs alterei ir. such a way as
to be of that tvpe.
(bb) "Capital expenditure" means an
expenditure for a physical or operational
change to an existing facility which ex-
ceeds the product of the applicable "an-
nual asset guideline repair allowance
psrcentage" specified in the latest edi-
tion of Internal Revenue Service Publi-
cation 534 and the existing facility's
basis, as defined bv section 1012 of the
Internal Revenue Code.
[40 FR 58415, December 16, 1975)
-------
§ 60.3 Abbreviations.
The abbreviations used in this part
have the following meanings:
A.S.T.M. — American Society Tor Testing and
Materials
Btu — British thermal unit
°C— degree Celsius (centigrade)
cal — calorie
CdS — cadmium sulflde
cfm — cubic feet per minute
CO — carbon monoxide
CO. — carbon dioxide
dscm — dry cubic meter(s) at standard con-
ditions
dscf — dry cubic fe«t at standard condition*
eq — equivalents
"F — degree Fahrenheit
g — gram(s)
gal— gallon(s)
g eq— gram equivalents
gr— grain(s)
hr — hour(s)
HC1 — hydrochloric acid
Hg — mercury
K..O — water
jfs — hydrogen sulfide
H'SO, — suHuric acid
in. — inch(es)
'K — degree Kelvin
k— 1,000
kg — kiiogram(s)
1— liter(s)
1pm— liter(s) per minute
Ib — pound(s)
m — meter (s)
meq — milliequivalent(s)
min — minute (s)
mg — milligram (s)
ml— mUliliter(s)
mm — millimeter(s)
mol. wt. — molecular weight
mV— millivolt
N.. — nitrogen
nm— nanometer (s)— 10-» meter
NO — nitric oxide
NO, — nitrogen dioxide
NO~ — nitrogen oxides
,
ppb— parts per billion
ppm — parts per million
psia — pounds per square inch absolute
°R — degree Rankine
s — at standard conditions
sec — second
SO, — sulfur dioxide
SO3 — sulfur trioxlde
^g— microgram(s) — 10-« gram
§ 60.4 Address.
(a) All requests, reports, application^
submittals, and other communications to
the Administrator pursuant to this part
shall be submitted in duplicate and Ad-
dressed to the appropriate Regional Of-
fice of the Environmental Protection
Agency, to the attention of the Director.
Enforcement Division. The regional of-
fices are as follows:
Region I (Connecticut, Maine. New Hamp-
shire, Massachusetts, Bhode Island, Ver-
mont), John F. Kennedy Federal Building,
Boston, Massachusetts 02203.
Region II (New York, New Jersey, Puerto
Rico, Virgin Islands), Federal Office Bulid-
ing, 26 Federal Plaza (Foley Square), New
York. N.Y. 10007.
Region III (Delaware, District of Columbia,
Pennsylvania, Maryland. Virginia, West Vir-
ginia), Curtis Building, Sixth »nd Walnut
Streets, Philadelphia, Pennsylvania 19108.
Region IV (Alabama, Florida, Georgia.
Mississippi, Kentucky, North Carolina, South
Carolina, Tennessee), Suite 300, 1421 Peach-
tree Street. Atlanta, Georgia 30309.
Region V (Illinois. Indiana, Minnesota,
Michigan, Ohio, Wisconsin), 1 North Wacker
Drive, Chicago, Illinois 60606.
Region VI (Arkansas, Louisiana, New
Mexico, Oklahoma, Texas), 1600 Patterson
Street, Dallas, Texas 75201.
Region VII (Iowa, Kansas, Missouri, Ne-
braska), 1735 Baltimore Street, Kansas City,
Missouri 63108.
Region VHI (Colorado, Montana, Nortli
Dakota, South Dakota, Utah. Wyoming), 19$
Lincoln Towers, 1830 Lincoln Street, Denver,
Colorado 80203.
Region IX (Arizona, California, Hawaii.
Nevada, Guam, American Samoa), 100 Cali-
fornia Street, San Francisco, California 94111.
Region X (Washington, Oregon, Idaho,
Alaska), 1200 Sixth Avenue, Seattle, Wash-
ington 98101.
(b) Section lll(c) directs the Admin-
istrator to delegate to each State, when-
appropriate, the authority to implement
and enforce standards of performanr«-
for new stationary sources located in
such State. All information required to
be submitted to EPA under paragraph
(a) of this section, must also be sub-
mitted to the appropriate State Agency
of any State to which this authority has
been delegated (provided, that each
specific delegation may except sources
from a certain Federal or State report-
ing requirement). The appropriate mail-
ing address for those States whose dc-la-
gation request has been approved is as
follows:
(A)-(E) [reserved].
(F) California
Bay Area Air Pollution Control District,
939 Ellis St., San Francisco, CA 94109.
Del Norte County Air Pollution Control
District, 5600 S. Broadway, Eureka, CA
95501.
Humboldt County Air Pollution Control
District, 5600 S. Broadway. Eureka, CA
95501.
Kern County Air Pollution Control
District, 1700 Rower St. (P.O. Box 997),
Bakerst'ield, CA 93302.
Monterey Bay Unified Air Pollution Con-
trol District. 420 Church St. (P.O. Box 487),
Salinas, CA 93901.
-------
tion date of the change. The Administra-
tor may request additional relevant in-
formation subsequent to this notice.
[40 FR 58415, December 16, 1975]
(d> Any owner or operator subject to
the provisions of this part shall maintain
a file of all measurements, including con-
tinuous monitoring system, monitoring
device, and performance testing meas-
urements; all continuous monitoring sys-
tem performance evaluations; all con-
tinuous monitoring system or monitoring
device calibration checks; adjustments
and maintenance performed on these
systems or devices; and all other infor-
mation required by this part recorded in
a permanent form suitable for inspec-
tion. The file shall be retained for at least
two years following the date of such
measurements, maintenance, reports, and
records.
[40 FR 46250, October 6, 1975]
(e) If notification substantial"/ similar
to that in paragraph (a) of this section
is required by any other State or local
agency, sending the Administrator a
copy of that notification .will satisfy the
requirements-of paragraph -f«->- of this
section.
[40 FR 58415, December 16, 1975]
(5) A notification of the date upon
which demonstration of the continuous
monitoring system performance com-
mences in accordance with §60.13(c).
Notification shall be postmarked not less
than 30 days prior to such date.
(b) Any owner or operator subject to
the provisions of this part shall main-
tain records of the occurrence and. dura-
tion of any startup, shutdown, or mal-
function in the operation of an affected
facility; any malfunction of the air pol-
lution control equipment; or any periods
during which a continuous monitoring
system or monitoring device is inopera-
tive.
(c) Each owner or operator required
to install a continuous monitoring sys-
tem shall submit a written report of
excess emissions (as defined in applicable
subparts) to the Administrator for every
calendar quarter. All quarterly reports
shall be postmarked by the 30th day fol-
lowing the end of each calendar quarter
and shall include the following informa-
tion:
(1) The magnitude of excess emissions
computed in accordance with § 60.13(h),
any conversion factor(s) used, and the
date and time of commencement and
completion of each time period of excess
emissions.
(2) Specific identification of each
period of excess. emissions that occurs
during startups, shutdowns, and mal-
functions of the affected facility. The
nature and cause of any malfunction (if
known), the corrective action taken or
preventative measures adopted.
& 60.8 Performance tests.
(a) Within 60 days after achieving the
maximum production rate at which the
affected facility will be operated, but not
jater than 180 days after initial startup.
of such facility and ?.t such olfic-r tune.':
P-K 1'iay bfl required by the AdmJnisJ'-ntor
un
-------
the alleged violation) Performance
Specification 1 in Appendix B of this
part, has been properly maintained and
(at the time of the alleged violation)
calibrated, and that the resulting data
have not been tampered with in any way.
[39 FR 39872, November 12, 1974J
(d) At all times, including periods of
startup, shutdown, and malfunction,
owners and operators shall, to the extent
practicable, maintain and operate any
affected facility including associated air
pollution control equipment in a manner
consistent with good air pollution control
practice for minimizing emissions. De-
termination of whether acceptable oper-
ating and maintenance procedures are
being used will be based on information
available to the Administrator which may
include, but is not limited to, monitoring
results, opacity observations, review of
operating and maintenance procedures,
and inspection if the source.
(e) (1) An owner or operator of an af-
fected facility may request the Admin-
istrator to determine opacity of emis-
sions from the affected facility during
the initial performance tests required by
I 60.8.
(2) Upon receipt from such owner or
operator of the written report of the re-
sults of the performance tests required
by I 60.8, the Administrator will make
a finding concerning compliance with
opacity and other applicable standards.
If the Administrator finds that an af-
fected facility is in compliance with all
applicable standards for which perform-
ance tests are conducted in accordance
with § 60.8 of this part but during the
time such performance tests are being
conducted fails to meet any applicable
opacity standard, he shall notify the
owner or operator and advise him that he
may petition the Administrator within
10 days of receipt of notification to make
appropriate adjustment to the opacity
standard for the affected facility.
(3) The Administrator will grant such
a. petition upon a demonstration by the
owner or operator that the affected fa-
cility and associated air pollution con-
trol equipment was operated and main-
tained in a manner to minimize the
opacity of emissions during the perform-
ance tests; that the performance tests
•were performed under the conditions es-
tablished by the Administrator; and that
the affected facility and associated air
pollution control equipment were in-
capable of being adjusted or operated to
meet the applicable opacity standard.
("4) The Administrator will establish
an opacity standard for the affected
facility meeting the above requirements
at a level at which the source will be
able, as indicated by the performance
and opacity tests, to meet the opacity
standard at all times during which the
source is meeting the mass or concentra-
tion emission standard. The Adminis-
trator will promulgate the new opacity
standard in the FEDERAL REGISTER.
[39 FR 39872, November 12, 1974]
§ 60.12 Circumvention.
No owner or operator subject to the
provisions of this part shall build, erect,
install, or use any article, machine,
equipment or process, the use of which
conceals an emission which would other-
wise constitute a violation of an applica-
ble standard. Such concealment in-
cludes, but is not limited to, the use of
gaseous diluents to achieve compliance
with an opacity standard or with a
standard which is based on the concen-
tration of a pollutant in. the gases dis-
charged to the atmosphere.
§ 60.14 Modification.
(a) Except as provided under para-
graphs (d), (e) and (f) of this section,
any physical or operational change to
an existing facility which results in an
increase in the emission rate to the
atmosphere of any pollutant to which a
standard applies shall be considered a
modification within the meaning of sec-
tion 111 of the Act. Upon modification,
an existing facility shall become an af-
fected facility for each pollutant to
which a standard applies and for which
there is an increase in the emission rate
to the atmosphere.
(b) Emission rate shall be expressed as
kg/hr of any pollutant discharged into
the atmosphere for which a standard is
applicable. The Administrator shall use
the following to determine emission rate:
(1) Emission factors as specified in
the latest issue of "Compilation of Air
Pollutant Emission Factors," EPA Pub-
lication No. AP-42, or other emission
factors determined by the Administrator
to be superior to AP-42 emission factors,
in cases where utilization of emission
factors demonstrate that the emission
level resulting from the physical or op-
erational change will either clearly in-
crease or clearly not increase.
(2) Material balances, continuous
monitor data, or manual emission tests
in cases where utilization of emission
factors as referenced in paragraph (b)
(1) of this section does not demonstrate
to the Administrator's satisfaction
whether the emission level resulting from
the physical or operational change will
either clearly increase or clearly not in-
crease, or where an owner or operator
demonstrates to the Administrator's
satisfaction that there are reasonable
grounds to dispute the result obtained by
the Administrator utilizing emission fac-
tors as referenced in paragraph (b)(l)
of this section. When the emission rate
is based on results from manual emission
tests or continuous monitoring systems,
the procedures specified in Appendix C
of this part shall be used to determine
whether an increase in emission rate has
occurred. Tests shall be conducted under
such conditions as the Administrator
shall specify to the owner or operator
based on representative performance of
the facility. At least three valid test
runs must be conducted before and at
least three after the physical or opera-
tional change. All operating parameters
which may affect emissions must be held
constant to the maximum feasible degree
for all test runs.
(c) The addition of an affected facility
to a stationary source as an expansion
to that source'or as a replacement for
an existing facility shall not by itself
bring v/ithin the applicability of this
part any other facility within that
source.
(d) A modification shall not be deemed
to occur if an existing facility undergoes
a physical or operational change where
the owner or operator demonstrates to
the Administrator's satisfaction (by any
of the procedures prescribed under para-
graph (b) of this section) that the total
emission rate of any pollutant has not
increased from all facilities within the
stationary source to which appropriate
reference, equivalent, or alternative
methods, as defined in § 60.2 (s), (t) and
(u), can be applied. An owner or operator
may completely and permanently, close
any facility within a stationary source
to prevent an increase in the total emis-
sion rate regardless of vrhether such
reference, equivalent or alternative
method can be applied, if the decrease
in emission rate from such closure can
be adequately determined by any of the
procedures prescribed under paragraph
(b) of this section. The o^mer or oper-
ator of the source shall have the burden
of demonstrating compliance with this
section.
(1) Such demonstration shall be in
writing and shall include: >i> The name
and. address of the owner or operator.
(ii) The location of the stationary
source.
(iii) A complete description of the ex-
isting facility undergoing the physical
or operational change resulting in an in-
crease in emission rate, any applicable
control system, and the physical or op-
erational change to such facility.
-------
(3) Emission rates established for the
existing facility which is undergoing a
physical or operational change resulting
in an increase in the emission rate, and
established for the facilities described
under paragraph (d) (1) (v) of this sec-
tion shall become the baseline for deter-
mining whether such facilities undergo
a modification or are in compliance with
standards.
(4) Any emission rate in excess of that
rate established under paragraph (d)
(3) of this section shall be a violation of
these regulations except as otherwise
provided in paragraph (e) of this sec-
tion. However, any owner or operator
electing to demonstrate compliance un-
der this paragraph (d) must apply to
the Administrator to obtain the use of
any exemptions under paragraphs (e>
(2), (e)(3), and (e) (4) of this section.
The Administrator will grant such ex-
emption only if, in his judgment, the
compliance originally demonstrated un-
der this paragraph will not be circum-
vented or nullified by the utilization of
the exemption.
(5) The Administrator may require
the use of continuous monitoring devices
and compliance with necessary reporting
procedures for each facility described in
paragraph (d)(l)(iii) and (d)UHv) of
this section.
(e) The following shall not, by them-
selves, be considered modifications under
this part:
(1) Maintenance, repair, and replace-
ment which the Administrator deter-
mines to be routine for a source category,
subject to the provisions of paragraph
(c) of this section and § 60.15.
(2) An increase in production rate of
an existing facility, if that increase can
be accomplished without a capital ex-
penditure on the stationary source con-
taining that facility.
(3) An increase in the hours of opera-
tion.
(4) Use of an alternative fuel or raw
material if, prior to the date any stand-
ard under this part becomes applicable
to that source type, as provided by § 60.1,
the existing facility was designed to ac-
commodate that alternative use. A
facility shall be considered to be designed
to accommodate an alternative fuel or
raw material if that use could be accom-
plished under the facility's construction
specifications, as amended, prior to the
change. Conversion to coal required for
energy considerations, as specified In sec-
tion 119(d)(5) of the Act, shall not be
considered a modification.
(5) The addition or use of any system
or device whose primary function is the
reduction of air pollutants, except when
an emission control system is removed
cc is replaced by a system which the Ad-
ministrator determines to be less en-
vironmentally beneficial.
(6) The relocation or change in
ownership of an existing facility.
(f) Special provisions set forth under
an applicable subpart of this part shall
supersede any conflicting provisions of
this section.
(g) Within 180 days of the comple- (3) The extent to which the comoo
tion of any physical or operational nents being replaced cause or contribute
change subject to the control measures to the emissions from the facUUy and
surfed in ™ra!™r,hc ,., Or (d) of (4) Any economic or technical limfu-
tions on compliance with applicable
standards of performance which are in-
herent in the proposed replacements
specified in paragraphs (a)
this section, compliance with all appli-
cable standards must be achieved.
§ 60.15 Reconstruction.
(a) An existing facility, upon recon-
.
(g) Individual subparts of this part
may include specific provisions which
—., ~.^*v*v*^ o^jcv-uiiu yiuvisions wnich
struction, becomes an affected facility, refine and delimit the concept of recon-
irrpsnpnr.ivo f\f antr /»Vior»er«i ^i-* •««^i*.*-t«« ~* is- — . *
struction set forth in this section.
6. Part 60 is amended by adding Ap-
pendix C as follows:
APPENDIX C— DETERMINATION
CHANGE
1. Introduction.
or EMISSION RATE
irrespective of any change in 'emission
rate.
(b) "Reconstruction" means the re-
placement of components of an existing
facility to such an extent that:
(1) The fixed capital cost of the new
Components exceeds 50 percent Of the l.l The following method shall be used to determine
fixed Capital COSt that WOUld be required Jfh«'her a Physical or operational change to an existing
to construct a comparable entirely new S?Df^!^h;nr,^I^J,n,t.ll?Keriy!?An.-rf^.lo.tl»
facility, and
(2) It is technologically and econom-
ically feasible to meet the applicable
standards set forth in this part.
(c) "Fixed capital cost" means the
capital needed to provide all the de-
preciable components.
e o e
atmrsphere. The method used is the Student's t test,
commonly used to make inferences from small samples,
1. Data.
2.1 Each emission test shall consist of n runs (usually
three) which produce n emission rates. Thus two sets of
emission rates are generated, one before and one after the
change, the two sflts heing of equal size.
2.2 When using mamml emission tests, except as pro-
vided in § 60.S(b) of this part, the reference methods of
K-^Emission rate for the i th run.
n-number of runs
3.3 Calculate the sample variance, S2, tor each set of
data using Equation 2.
n-l
n-1
(2)
3.4 Calculate the pooled estimate,
tion 3.
using Equa-
^Tr'fC UUI"tJuue"ui- . , Appendix A to this'prirts^TlVusVrt in accordance with
(d) If an owner or Operator Of an 'he procedures specified in the applicable subpart both
existing facility proposes to replace com- ^Twh™n^L^l'r'™R'to ob'?in % d,at?'
ponents, and the fixed capital cost of the ^^^™n^^X%^*&**£
new components exceeds 50 percent Of formefl-.Va]irl data using the averaging time which would
the fixed capital cost that would be re- ducteTsMi 'L*^^ emi:isi
-------
Test a: Test b
Run 1. 100 115
Run2. 95 120
JRunS. HO 125
5.2 Using Equation 1—
5.3 Using Equation 2—
(100- 102)'+ (95- 102P+ (110- 102 )»
3—1
=58.5
_ (115-120)3+(120-120)'+(125-120)'
3-1
= 25
5.4 Using Equation 3—
(3-1) (58.5)+ (3-1) (25)-|'''»_
6-46
5.5 Using Equation 4—
120-102
t — -
-, = 3.412
6A
6.6 Since (rti+7i!-2)=4, ('=2.132 (from Table 1). Thus
sine* t>tf the difference in the values of A'« and Kb is
significant, and there has been an increase in emission.
rate to the atmosphere.
6, Coitlimujtis Monitoring Data.
6.1 Hourly averages from continuous monitoring de-
vices, whrre available, shaiild be usedasdaca points and
the above procedure followed.
Subpart I—Standards of Performance for
Asphalt Concrete Plants
§ 60.90 Applicability and designation of
affected facility.
The affected facility to which the pro-
visions of this subpart apply is 'each
asphalt concrete plant. -For the purpose
of this subpart, an asphalt concrete plant
is comprised only of any combination of
the following: Dryers; systems for
screening, handling, storing, and weigh-
ing hot aggregate; systems for loading,
transferring, and storing mineral filler;
systems for mixing asphalt concrete;
and the loading, transfer, and storage
systems associated with emission control
systems.
§ 60.91 Definitions.
As used in this subpart, all terms not
defined herein shall have the meaning
given them in the Act and in subpart A
of this part.
(a) "Asphalt concrete plant" means
any facility, as described in § 60.90; used
to manufacture asphalt concrete by
heating and drying aggregate and mix-
Ing with asphalt cements.
§ 60.92 Standard for paniculate matter.
(a) On and after the date on which
the performance test required to be con-
ducted by § 60.8 Is completed, no owner
or operator subject to the provisions of
this subpart shall discharge or cause the
discharge into the atmosphere from any
affected facility any gases which:
(1) Contain participate matter in ex-
cess of 90 mg/dscm (0.04 gr/dscf).
(2) Exhibit 20 percent opacity, or
greater.
[40 FR 46250, October 6, 1975J
§ 60.93 Test methods and procedures.
(a) The reference methods appended
to this part, except as provided for In
§60.8(b), shall be used to determine
compliance with the standards prescribed
in § 60.92 as follows:
(1) Method 5 for the concentration of
particulate matter and the associated
moisture content,
(2) Method 1 for sample and velocity
traverses,
(3) Method 2 for velocity and volu-
metric flow rate, and
(4) Method 3 for gas analysis.
(b) 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 (0.53 dscf/min) except that
shorter sampling times, when necessi-
tated by process variables or other fac-
tors, may be approved by the Adminis-
trator.
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
REPORT NO.
EPA 340/1-75-005A
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
Inspection Manual for Enforcement of New Source
Performance Standards:. Asphalt Concrete Plants
5. REPORT DATE
June, 1975
S. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
JACA Corp.
506 Bethlehem Pike
Fort Washington, PA 19034
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-02-1356 Task 2
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Protection Agency
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
One of a series of NSPS enforcement inspection manuals
16. ABSTRACT
This manual presents guidelines for federal enforcement personnel in
determining whether new or modified asphalt concrete plants are in compliance
with New Source Performance Standards (NSPS). The manual includes: detailed
process information, characterization of atmospheric emissions from these
sources, control methods employed, instruction in obtaining key process
parameters for use in source evaluation, and detailed procedures for mon-
itoring emission tests and performing routine inspections.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Asphalt Concrete
Enforcement
Emission Testing
Fugitive dusts
New Source Performance
Standards
Enforcement
Emission Testing
Fugitive dusts
13B
14D
11D
13. DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS (This Report}
Unclassified
21. NO. OF PAGES
79
20. SECURITY CLASS (Thispage}
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
•:, U. S. GOVERNMENT PRINTING OFFICE : 1976 — 623-190/483
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