&EPA
United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA-450/3-80-016
March 1980
Air
Source Category
Survey: Mineral Wool
Manufacturing Industry
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EPA-450/3-80-016
Source Category Survey;
Mineral Wool
Manufacturing Industry
Emission Standards and Engineering Division
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air, Noise, and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
March 1980
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This report has been reviewed by the Emission Standards and Engineering
Division, Office of Air Quality Planning and Standards, Office of Air, Noise,
and Radiation, Environmental Protection Agency, and approved for publica-
tion . Mention of company or product names does not constitute endorsement
by EPA. Copies are available free of charge to Federal employees, current
contractors and grantees, and non-profit organizations - as supplies permit
from the Library Services Office, MD-35, Environmental Protection Agency
Research Triangle Park, NC 27711; or may be obtained, for a fee, from the
National Technical Information Service, 5285 Port Royal Road, Springfield,
VA 22161.
Publication No. EPA-A5J)/3-aO-Ol6
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TABLE OF CONTENTS
1.0 Summary 1-1
2.0 Introduction 2-1
3.0 Conclusions and Recommendations 3-1
4.0 Description of the Mineral Wool Industry 4-1
4.1 Definition of the Source Category 4-1
4.2 Industry Production 4-6
4.2.1. Mineral Wool Sales and Production . . 4-6
4.2.2 Projected Demand for Insulation . . . 4-7
4.2.3 The Current Insulation Market .... 4-14
4.2.4 Estimated Industry Expansion 4-15
4.3 Process Description 4-17
5.0 Air Emissions Developed in the Source Category . . 5-1
5.1 Plant and Process Emissions 5-1
5.2 Uncontrolled Annual Emissions for a Typical
Mineral Wool Plant 5-13
5.3 Total National Emissions from Mineral Wool
Manufacturing 5-15
6.0 Emission Control Systems 6-1
6.1 Current Control Technology Practices 6-1
6.2 Alternative Control Techniques 6-13
6.3 Impact of Mineral Wool Manufacturing on
Ambient Air Quality 6-13
7.0 Emission Data 7-1
7.1 Availability of Data 7-1
7.2 Sample Collection and Analysis 7-1
8.0 State and Local Emission Regulations 8-1
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LIST OF TABLES
TABLE PAGE
4-1 Mineral Wool Manufacturers 4-3
4-2 Insulation Industry Shipments by Material, 1976 4-8
4-3 Demand for Insulation by Material 4-8
4-4 Building Construction Insulation Demand 4-8
4-5 Existing Capacity and Approved/Committed Capacity
Expansion for Supply of Insulation Materials for
One-to-Four Family Housing Units (Attic/Ceiling
and Sidewall Insulation) 4-13
4-6 Existing Capacity and Approved/Committed Capacity
Expansion for Supply of Insulation Materials for
One-Family Housing Units (Attic/Ceiling
Insulation Only) 4-13
5-1 Uncontrolled Particulate Emissions from
Mineral Wool Cupolas 5-3
5-2 Average Uncontrolled Sulfur Oxide and Hydrogen
Sulfide Emission Concentrations and Factors
for Mineral Wool Cupolas 5-5
5-3 Uncontrolled Carbon Monoxide Emissions from
Mineral Wool Cupolas 5-7
5-4 Uncontrolled Nitrogen Oxide Emissions from
Mineral Wool Cupolas 5-7
5-5 Uncontrolled Particulate Emission from
Mineral Wool Blowchambers 5-9
5-6 Uncontrolled Particulate Emissions from
Mineral Wool Curing Ovens 5-11
5-7 Uncontrolled Emission Factors for Mineral
Wool Manufacturing 5-14
5-8 Uncontrolled Potential Emissions from a Typical
Mineral Wool Manufacturing Plant 5-14
5-9 Potential Emissions from a Typical Mineral Wool
Manufacturing Plant Controlled to Meet a
Typical SIP 5-16
IV
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TABLE PAGE
5-10 Nationwide Potential Emissions from the Mineral
Wool Manufacturing Industry for 1979
Assuming Compliance with SIP's 5-17
6-1 Summary of Air Pollution Controls Operating
in the United States Mineral Wool Industry 6-2
6-2 Controlled Particulate Emissions from
Mineral Wool Cupolas 6-4
6-3 Controlled Particulate Emissions from
Mineral Wool Blowchambers 6-8
6-4 Controlled Particulate Emisssions from
Mineral Wool Curing Ovens 6-10
6-5 Alternative Control Systems 6-14
6-6 Maximum 24-Hour and Annual Ground Level
Particulate Concentrations Around Typical
Mineral Wool Plants 6-16
6-7 Maximum 1-Hour and 8-Hour Ground Level Carbon
Monoxide Concentrations Around Typical
Mineral Wool Plants 6-17
7-1 Availability of Emission Test Results 7-2
8-1 Summary of Particulate Emission Regulations for
New Mineral Wool Manufacturing Processes 8-2
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LIST OF FIGURES
FIGURE PAGE
4-1 Estimated Structural Insulation Capacity,
1976-1985 4-10
4-2 Powell Process 4-19
4-3 Downey Process 4-19
4-4 Typical Mineral Wool Process Flow Diagram 4-22
VI
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1. SUMMARY
The term "mineral wool" can be used to describe any fibrous glassy
substance made from minerals or mineral products. For the purpose of
this study, mineral wool has been defined to include only those fibers
made primarily from natural rock or metallurgical slag. Mineral wool is
widely used as a structural and industrial insulation and in other
products where the fiber is added to impart structural strength or fire
resistance.
The number of mineral wool plants peaked at between 80 and 90 in the
1950's and then declined as fibrous glass wool penetrated the insulation
market. There are about 26 mineral wool plants currently operating in
the United States. These plants are typically located near a source of
metallurgical slag with concentrations of plants being in Indiana,
Alabama, Pennsylvania, and Texas. The remaining plants are located in
10 other States.
During the years 1972 to 1976, mineral wool insulation shipments
were estimated to be about 600 million pounds per year, growing at an
annual rate of less than 2 percent. This compares to an annual growth
rate of 17 percent for fibrous glass insulation during the 1960 to 1974
period. Total mineral wool insulation sales were approximately 80 to 100
million dollars in 1976, with the largest manufacturer having sales of 35
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to 37 million dollars. Sales of mineral wool insulation have grown since
the early 1960's at an annual rate of 3 percent in constant dollars.
The demand for mineral wool has historically followed the general
.conomic cycle since the majority of insulation materials have been used
in the construction of new housing. It was anticipated that the 1977
income tax credit for energy conservation expenditures on existing homes
would greatly increase the demand for insulation, but this retrofit
market has not developed and mineral wool manufacturers are currently
operating at about 60 percent of capacity. If an increase in sales were
to occur, existing manufacturing capabilities of the insulation industry
should be sufficient to meet any foreseeable demand.
Despite existing insulation production capacity and lack of
increased demand, the capacity equivalent of one new mineral wool plant
could be built in the next 5 years in an area of the country where it
could compete for the existing insulation market.
Mineral wool is manufactured by melting rock and slag in a cupola
using coke as fuel. The molten minerals are fiberized on a spinning
rotor using a high velocity stream of air or steam to assist in fiber
attenuation. An oil or binding agent is applied to the fiber before it
is collected on a wire mesh conveyor in an area known as the blowchamber.
Mineral wool containing the binder is cured in an oven, cut into batts,
and usually covered with a vapor barrier of treated paper or foil. For
loose wool products, no binding agent is applied and the curing oven is
eliminated.
The major sources of emissions from the manufacturing of mineral
wool are the cupolas, blowchambers, and curing ovens. A typical mineral
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wool plant has two parallel production lines, a batt line and a wool
line. The batt line consists of a cupola, blowchamber, and curing oven.
The wool line has only a cupola and a blowchamber.
The most significant emission source in the process is the cupola,
with approximately 3600 Mg/year (3960 Tons/year) of carbon monoxide (CO)
being emitted from a typical plant. A CO control system is currently in
operation at only one United States plant, and it is estimated that a
98 percent control efficiency could be achieved with controlled emissions
of 180 Mg/year. Uncontrolled particulate emissions from the cupolas
at a typical plant are about 366 Mg/year (403 Tons/year), but actual
emissions would be controlled to approximately 54 Mg/year (59 Tons/year)
to comply with the typical SIP. Baghouses are applied to two-thirds of
the cupolas in operation, although cyclones, scrubbers, and ESP's are
also used to control cupola particulate emissions. Particulate emissions
from the cupolas at a typical plant could be reduced to 10 Mg/year
(11 Tons/year) if baghouse performance equivalent to the average for
baghouse test results reported in this study is assumed.
Mineral wool blowchambers are a significant source of particulates
and are controlled by low energy wet scrubbers at about half the plants.
Lint cages are the next most common control device in operation.
Emissions from the blowchambers at a plant controlled to meet a typical
SIP would be about 39 Mg/year (43 Tons/year). Two fabric filters are
reportedly in use on blowchamber exhausts, but no test results could be
obtained during this study. Assuming a fabric filter could limit
blowchamber particulate emissions to 23 mg/scm (0.01 gr/scf), then
blowchamber emissions from a typical plant could be reduced to 14 Mg/year
(15 Tons/year).
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The curing oven is a smaller source of particulate emissions than
the cupola and blowchamber. Uncontrolled particulate emissions from the
typical curing oven are about 14 Mg/year (15 Tons/year). Approximately
rilf the plants for which data were reported use afterburners to control
particulate and volatile organic compound (VOC) emissions from curing
ovens. A test indicates that a 50 percent reduction can be achieved
using a direct-flame afterburner. A cooling section follows the oven
where air at ambient temperatures is forced through the cured wool.
Nationwide emissions of primary pollutants produced by the mineral
wool manufacturing industry, operated at full capacity and controlled
to meet the SIP's, are estimated below:
Particulates Carbon Monoxide
Process^ Source Mg/year (Tons/year) Mg/year (Tons/year)
95,600 (105,300)
Cupolas
Blowchambers
Curing Ovens
Cooler
1,450
1,040
270
190
(1,600)
(.1,150)
(290)
(210)
Totals 2,950 (3,250) 95,600 (105,300)
There are other pollutants emitted from the process. However, the only
pollutant generally controlled by the SIP's is particulate matter. A
detailed emission inventory is contained in Table 5-10.
States typically regulate mineral wool manufacturing under general
process emission regulations. The most common formula for determining
n 62
allowable particulate emissions is E = 3.59p where E is the allowable
emissions in Ibs/hour and p is the process weight rate in tons/hour.
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There are EPA reference methods for evaluation of several pollutants
emitted by mineral wool processes; a list of methods that may be applied
to mineral wool manufacturing is contained in Chapter 7.
It is not recommended that an NSPS be developed for the mineral wool
manufacturing industry at this time due to the following factors:
* The mineral wool industry is currently operating at about 60
percent of capacity. Existing production capacity is sufficient to meet
increased demand even if the insulation market were greatly stimulated.
* Growth of the industry is considered unlikely. Construction of
one new plant in the next 5 years is possible, but expansion by more than
one plant is considered to be improbable at this time.
* The emission reduction potential of an NSPS for particulates is
approximately 72 Mg/year (80 Tons/year) if cupola, blowchamber, and curing
oven particulate emissions from one new plant were controlled by NSPS.
The emission reduction potential for cupola CO emissions is estimated to
be 3,420 Mg/year.
* Existing State regulations control particulate emissions from
the cupola and blowchamber so that the maximum impact on ambient air
quality is estimated to be less than 3 percent of the 24-hour national
primary ambient air quality standard and less than 2 percent of the annual
national primary ambient air quality standard. The maximum estimated carbon
monoxide concentration for uncontrolled cupolas was also estimated to be
less than 5 percent of the CO 1-hour national primary ambient air quality
standard and less than 10 percent of the 8-hour national primary ambient
air quality standard.
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2. INTRODUCTION
Mineral wool is a widely used structural and industrial insulation
material which is manufactured primarily from natural rock and metal-
lurgical slag. Although sometimes considered to be mineral wool, fibrous
glass wool was excluded from this survey.
In a typical process, slag and rock are melted in a cupola using
coke as fuel. The molten minerals are drained from the furnace and
dropped on a spinning rotor to fiberize the material. Using fans to
create a downdraft, the mineral fiber is then collected on a wire mesh
conveyor in an area known as the blowchamber. The wool may then be
granulated and packaged for shipment or conveyed to an oven for curing of
a binder which adds structural rigidity to the insulation. The cured
fiber blanket may then be cut into batts and covered with a vapor barrier
of treated paper or foil.
Those emission sources primarily examined during this study were the
exhausts from mineral wool cupolas, blowchambers, and curing ovens.
Emissions from other mineral wool manufacturing processes were judged
not to be significant enough to be considered for development of new
source performance standards.
The authority to promulgate standards of performance for new sources
is derived from Section 111 of the Clean Air Act. Under the Act, the
Administrator of the United States Environmental Protection Agency is
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directed to establish standards relating to the emission of air
pollutants and is accorded the following powers:
1. Identify those categories of stationary emission sources that
contribute significantly to air pollution, the emission of which could
be reasonably anticipated to endanger the public health and welfare.
2. Distinguish among classes, types, and sizes within categories
of new sources for the purpose of establishing such standards.
3. Establish standards of performance for stationary sources which
reflect the degree of emission reduction achievable through application
of the best system of continuous emission reduction, taking into con-
sideration the cost, energy, and environmental impacts associated with
such emission reduction.
The term "stationary source" means any building, structure, facility,
or installation which emits or may emit any air pollutants. A source is
considered new if its construction or modification is commenced after
publication of the proposed regulations. Modifications subjecting
an existing source to such standards are considered to be any physical
change in the source or change in methods of operation which results in
an increase in the amount of any air pollutant emitted. Reconstructions
subjecting an existing source to these standards are considered to be any
replacement of components of an existing facility the fixed capital cost
of which exceeds 50 percent of the fixed capital cost that would be
required to construct a comparable entirely new facility. The conditions
under which a modified or reconstructed source is subject to an NSPS are
defined in Title 40, Code of Federal Regulations, Part 60.
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The Clean Air Act amendments of 1977 require promulgation of the new
source standards on a greatly accelerated schedule. As part of the
schedule, this source category survey was performed to determine if
development of new source performance standards for the mineral wool
manufacturing industry was justified and to identify what processes and
pollutants, if any, should be subject to regulation. In determining
priorities for promulgating new source standards, the following are
considered:
1. The quantity of air pollutant emissions which each source
category will emit or will be designed to emit.
2. The extent to which each pollutant may reasonably be anticipated
to endanger public health or welfare.
3. The mobility and competitive nature of each source category and
the consequent need for nationally applicable new source performance
standards.
Information necessary for development of the mineral wool manufacturing
source category survey was gathered through the following activities:
1. Collection of process and emission data from literature searches
and contacts with State and local air pollution control agencies.
2. Visiting several mineral wool plants to develop an understanding
of manufacturing processes, and to collect data on operating air pollution
control equipment.
3. Contacting representatives of industry, trade associations, and
government agencies to gather information on current mineral wool
production and projected industry expansion.
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3. CONCLUSIONS AND RECOMMENDATIONS
3.1 CONCLUSIONS
The number of mineral wool plants has decreased from more than 80 in
the 1950's to about 26 plants 1n 1979. This decline in the number of
plants is primarily due to the penetration of the insulation market by
fibrous glass and cellulosic materials.
The oil embargo of 1973 - 1974 and the following OPEC price
escalations resulted in increased interest in energy conservation in new
and existing structures. As a result of increased consumer demand,
mineral insulation (fibrous glass and mineral wool) industry doubled
production capacity during the 1970's in anticipation of further
increases in the insulation market. Expectations of greatly increased
demand were heightened by the 1977 income tax credit for energy
conservation expenditures on existing homes and announcement of Minimum
Property Standards by the Department of Housing and Urban Development,
which specify thermal insulation efficiencies for new housing.
Large increases in demand for insulation productions which were
anticipated a few years ago have not developed. Mineral wool production
capacity which was added in the last several years has not been utilized,
and the mineral wool industry is currently operating at about 60 percent
of capacity. If the insulation market were greatly stimulated, existing
manufacturing capacity should be sufficient to supply any foreseeable
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demand. In 1977, it was estimated that the then existing production
capacity and committed capacity expansion could supply sufficient
materials to insulate the 25.5 million housing units needing insulation
improvement by 1981 if the activity was restricted to attics only, or by
1983 if upgrading included sidewalls as well as attics. If only single-
family dwellings were retrofitted, the thermal improvement could be
completed in less time.
Two new mineral wool plants have begun operation in the last 2
years. One plant is currently under construction and is scheduled to
begin operation in 1980. Two of these plants were built with only a
single production line; the other plant was constructed with two production
lines but one of those lines has never been put into operation. It has
been estimated that at least 2 years would be required to bring a new
mineral wool plant on line. These most recently constructed plants were
apparently planned at the time when increased demand for insulation was
anticipated and existing plants were operating near capacity.
In the past 2 years, at least 2 mineral wool plants have closed.
One plant was operated by the U.S. Gypsum Company and the other by the
Johns-Manville Corporation. The Johns-Manville plant produced only bulk
mineral wool fiber which was used in the manufacturing of ceiling tile.
Before closing their operations, Johns-Manville performed a detailed
market survey and determined that there was no national demand for bulk
2
mineral wool.
Despite the existing lack of increased demand for insulation, it is
still possible that the mineral wool industry will add the capacity
equivalent of one new plant in the next 5 years. Both raw materials
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and finished products are bulky, making it economically attractive for a
plant to locate either near a source of raw materials or product demand.
A new mineral wool plant could compete for the existing insulation market
in some areas of the country where regional competition was not great.
Major modifications or reconstructions to existing plants are not
considered likely to occur in significant numbers due to current market
conditions and existing production capacity.
Data were obtained for both uncontrolled and controlled emissions
from the mineral wool process from several State/local control agencies.
Data summaries were utilized from these test reports to determine
pollutant concentrations from control devices, uncontrolled and controlled
emission factors, and amounts of pollutants emitted from typical mineral
wool processes. There are six particulate emission tests for baghouse
control of cupolas, one particulate test for an ESP on a curing oven,
and one test of CO emissions from a cupola CO control system which would
require review in detail if a study to develop an NSPS were to be initiated.
Detailed test data would have to be obtained from the control agencies
and/or plants before such a review could be accomplished.
There are EPA reference methods for evaluation of some pollutants
emitted by mineral wool processes. These reference methods are listed in
Chapter 7 of this report.
The emission reduction achievable with an NSPS, impact of
pollutant(s) on public health or welfare, and the ability of the source
to locate in State(s) with less stringent air pollution standards than
other States were the major factors considered before making a recom-
mendation whether an NSPS should or should not be developed for mineral
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wool manufacturing. A description of how these factors were analyzed is
outlined in the following discussion.
The most significant emission source in the mineral wool process is
the cupola. The largest emission of a pollutant occurs from the cupola
at an approximate uncontrolled rate of 3,600 Mg/year of carbon monoxide.
A CO control system is operating at 1 United States plant, and a recent
test has indicated a control efficiency as high as 98 percent. If a
more conservative control efficiency of 95 percent is assumed, carbon
monoxide emissions could be reduced to 180 Mg/year, a reduction equivalent
to about 3,420 Mg/year for each new plant constructed. The next greatest
amount of an uncontrolled pollutant is the particulate emitted from the
cupolas which amounts to about 366 Mg/year, but the actual emissions would
be controlled to approximately 54 Mg/year to comply with the typical SIP.
Baghouses are applied to two-thirds of the cupolas although cyclones
(alone or in combination with other devices), wet scrubbers, and an ESP
are also used to control cupola particulate emissions. If baghouse
performance equivalent to the average of the controlled emission factor
contained in Table 6-2 is used as a basis, cupola particulate emissions
from a typical plant could be reduced to about 10 Mg/year, or a decrease
of approximately 44 Mg/year for each new plant constructed. There are
emissions of sulfur oxides, hydrogen sulfide, and nitrogen oxides from
the cupola, but no control technology has been demonstrated for these
pollutants at any United States plants.
The mineral wool blowchamber is a significant particulate source,
and the most commonly applied control devices are low energy scrubbers
which are used at about half the plants. Lint cages are the next most
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commonly used control device with a few cyclones reportedly in use. The
emissions from blowchambers would be 39 Mg/year at a mineral wool plant
complying with the SIP. Two fabric filters are reported to be used to
control blowchamber particulate emissions although no test results could
be obtained during this study for this application. If it is assumed that
fabric filters can reduce blowchamber emissions to 0.011 gr/scf (this
degree of control is reported in Table 6-3 for a wet scrubber and ESP
combination and, for the purposes of this analysis, it was assumed that
fabric filtration could achieve equivalent results), then blowchamber
emissions would be reduced to about 14 Mg/year, a reduction of about
25 Mg/year for each new plant constructed. The blowchambers are also
sources of some volatile organic compounds (VOC) and two afterburners
are reported to be used to control blowchamber emissions. However, the
large volume of air typically exhausted from blowchambers would probably
make operating costs prohibitive for afterburner control of blowchamber
exhausts at most plants, and no emission reduction benefit for blowchamber
VOC emissions was considered for that reason.
The curing oven is a smaller source of particulate than the cupola
and blowchamber, but about half of the plants for which data were
reported use afterburners to control particulate and VOC emissions from
curing ovens. An emission reduction of 50 percent of uncontrolled curing
oven particulate emissions was assumed based upon a test reported in
AP-40 for a direct-flame afterburner controlling curing oven particulate.
On this basis, it is estimated that uncontrolled particulate emissions
could be reduced from 14 Mg/year to 7 Mg/year or a reduction of 3 Mg/year
from the 10 Mg/year emission level of the typical SIP for each new plant
construction.
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The emission reduction potentially achievable by development of
an NSPS was calculated assuming the construction of one new plant or
equivalent within the next 5 years. Due to regional market considerations,
there is a possibility that a new plant will be built even though existing
production capacity far exceeds current demand. At this time, it is
considered unlikely that additional growth will occur. The emission
reduction achievable at the end of the 5-year period by an NSPS for carbon
monoxide and particulates from cupolas and particulates from blowchambers
and curing ovens is summarized below:
Emission Reductions Achievable by NSPS - Mg/year
Particulates CO
Cupola 44 3,420
Blowchamber 25
Curing Oven 3
Totals 72 3,420
An estimate of the impact of mineral wool manufacturing emissions
on the ambient environment was evaluated by calculating maximum ground
level concentrations using two simplified Gaussian dispersion models. The
pollutants evaluated were carbon monoxide emissions from mineral wool
cupolas and particulate emissions from cupolas and blowchambers. An
uncontrolled emission rate was assumed for cupola CO emissions under
the typical SIP emission standard since only one plant has a control
system for cupola CO emissions while emission rates equivalent to the
typical SIP were assumed for particulate emissions from the cupola
and blowchamber. The maximum ambient particulate concentrations were
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estimated to be less than 3 percent of the 24-hour national primary
ambient air quality standard for total suspended particulate and less than
2 percent of the annual national primary ambient air quality standard
for total suspended particulate from either the cupola or blowchamber
complying with the typical SIP. The maximum estimated ambient CO
concentration for an uncontrolled cupola was less than 5 percent of the
CO 1-hour national primary ambient air quality standard and less than
10 percent of the CO 8-hour national primary ambient air quality standard.
For cupolas equipped with CO control systems, the maximum estimated
1-hour and 8-hour concentrations are less than 1 percent of the respective
national primary ambient air quality standards. Plant location appears
to be generally dependent upon a source of raw materials, especially slag,
and market considerations. Selection of a site based upon less stringent
State emission standards is not likely to be as major a consideration
in site selection as would the market area to be served by a new plant.
It is not recommended that an NSPS be developed for mineral wool
manufacturing at the present time. The factors that support this
recommendation are:
* The mineral wool manufacturing industry is presently operating at
about 60 percent of capacity. Sufficient excess capacity exists to supply
insulating materials even with strong stimulation of the market. There
are at least two idle mineral wool plants which could possibly be brought
into production if the insulation market improved significantly.
* Growth is considered fairly unlikely for the mineral wool industry.
One plant construction in the next 5 years is a possibility, but expansion
by more than one plant would have to be considered as improbable unless
market conditions change drastically.
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* The emission reduction potential of an NSPS for participates is
approximately 72 Mg/year if cupola, blowchamber, and curing oven emissions
of one new plant are controlled with NSPS. The emission reduction potential
for cupola carbon monoxide emissions is estimated to be 3,420 Mg/year.
An estimate of maximum impact on ambient air quality indicates
that existing SI^'s control cupola and blowchamber particulate emissions
to less than 3 percent of the 24-hour and less than 2 percent of the
annual average national primary ambient air quality standards. The
maximum estimated CO concentrations were found to be less than 5 percent
of the 1-hour and less than 10 percent of the 8-hour national primary
ambient air quality standards.
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REFERENCES
1. ICF, Incorporated. Supply Response to Residential Insulation
Retrofit Demand. Report to the Federal Energy Administration. Contract
Number P-14-77-5430-0. Washington, D.C. June, 1977. Page 18.
2. Memorandum from L. Anderson, United States Environmental Protection
Agency, to J.U. Crowder, United States Environmental Protection Agency.
August 22, 1979. Trip Report to Johns-Manville mineral wool manufacturing
plant, Alexandria, Indiana.
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4. INDUSTRY DESCRIPTION
4.1 SOURCE CATEGORY
"Mineral wool" is a term that can be used to describe any fibrous
glassy substance made from minerals (e.g., natural rock) or mineral
products (e.g., slag or glass). For the purpose of this study, mineral
wool has been defined to include only those fibers made from natural
rock (rock wool), slag (slag wool), or a mixture of rock and slag.
Thus, fibrous glass wool has been excluded.
Mineral wool consists of silicate fibers typically 4 to 7 micro-
meters in diameter. It is widely used as a structural and industrial
insulation and in the manufacturing of other products where the fiber is
added to impart structural strength or fire resistance. Uses of mineral
wool include:
* "Blowing" wool or "pouring" wool that can be blown pneumatically
or poured by hand into the structural spaces of buildings.
* Batts, which may be covered with a vapor barrier of paper or
foil, shaped to fit between the structural members of buildings.
* Industrial and commercial products such as high density fiber
felts and blankets used for insulating boilers, ovens, pipes,
refrigerators, or other process equipment.
* Bulk fiber that is used as a raw material in the manufacturing
of other products, such as ceiling tile, wall board, spray-on
insulation, cement, and mortar.
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Some crude forms of slag wool were produced as early as 1840, but
it was not until late in the 19th century that mineral wool was
manufactured on a modest scale. One of the first successful slag wool
processes began operation in Manchester, England, around 1885, using
blast furnace slag as a raw material. C.C. Hall, using naturally
occurring limestone as a raw material, first manufactured rock wool
about 1900 in Alexandria, Indiana. Prior to the development of Hall's
rock wool process, at least one slag wool plant was in operation in the
United States. Although several mineral wool plants were in operation
in the early 1900's, it was not until after the first World War that
mineral wool began to acquire a substantial market. By 1939, there were
25 mineral wool plants operating in the United States.
The number of mineral wool plants peaked at between 80 and 90
plants in the 1950's and then declined as fibrous glass insulation
2
penetrated the market which had previously been held by mineral wool.
Many of the plants which closed were small, single line facilities
which have been replaced by larger, multi-line installations. Today, about
26 mineral wool plants are operating in the United States. Table 4-1 is
a listing of mineral wool manufacturing facilities. One new mineral wool
plant is presently under construction in Woodbridge, Virginia, and is
scheduled to begin operation in 1980.
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Table 4-1. Mineral Wool Manufacturers
Alabama
Celotex
Rockwool Manufacturing Company
U. S. Gypsum Company
Birmingham
Leeds
Birmingham
California
Rockwool Industries
Fontana
Colorado
Rockwool Industries
Pueblo
Illinois
Forty Eight Insulations
Aurora
Indiana
Celotex
Guardian Industries
L. C. Cassidy and Son
Johns-Manville Corporation
Rockwool Industries
U. S. Gypsum Company
Lagro
Huntington
Wabash
Alexandria (closing 9/79)
Alexandria
Wabash
Minnesota
Carney Insulation
Conwed Corporation
Mankato
Red Wing
Missouri
Eagle-Richer Corporation
Rockwool Industries
Joplin
Cameron
New Jersey
U. S. Mineral Products
Stanhope
4-3
-------
Table 4-1. Mineral Wool Manufacturers (Continued)
North Carolina
Spring Hope Rockwool
Spring Hope
Ohio
Forty Eight Insulations
Alliance
Pennsylvania
Bethlehem Steel Corporation
Celotex
Bethlehem (2 plants)
Pittston
Tennessee
Fiberfine
Memphis
Texas
Mineral Wool Manufacturing
Rockwool Industries
U. S. Gypsum Company
Rogers
Bel ton
Corsicana
Washington
U. S. Gypsum Company
Tacoma
4-4
-------
When examining production and growth of the mineral wool
manufacturing industry, it is important to consider the influence of
the other types of thermal insulation materials which compete with
mineral wool for the existing market. There are seven primary types of
thermal insulation materials used in residential, commercial, and
industrial structures: fibrous glass wool, mineral wool, cellulose,
mineral granules, foams, insulating board, and aluminum foil. However,
fibrous glass wool, mineral wool, and cellulose account for the vast
majority of the value of shipments in the insulation industry.
Insulation properties of a material are measured in "R" values.
"R" is a measure of resistance to conduction of heat; the higher the "R"
value, the greater the resistance to heat transfer through the material.
Fibrous glass insulation has a thermal resistance of approximately
R-3.2 per inch of thickness for batts and 2.2 for blowing wool. The
insulation is relatively lightweight as compared to mineral wool and
cellulose insulation.
While mineral wool has somewhat better high temperature insulation
properties and fire prevention characteristics than fibrous glass wool,
it weighs about 2.2 times more per unit volume. The thermal resistance
of mineral wool insulation is about R-3.4 per inch for batts and 2.9 for
blowing wool.
Cellulosic insulation can be made from newsprint, paperboard, or
wood fiber, with the addition of fire retardant chemicals. Raw
materials are plentiful, the technology is simple, and the capital
requirements to produce the material are not high, making cellulosic
4-5
-------
Insulation less expensive than many other products. This lower cost
alternative is particularly attractive to those who want to retrofit an
existing structure as economically as possible. Cellulose insulation
weighs about 3.5 times more per unit volume than fibrous glass, and the
fire retardant properties of cellulose are not as good as glass or
mineral wool.
4.2 INDUSTRY PRODUCTION
In this section, mineral wool sales and production are discussed,
and future demand is projected. Also described are the current
insulation market conditions and how this affects expansion of the
mineral wool manufacturing industry.
4.2.1 Mineral Wool Sales and Production
Although Standard Industrial Classification (SIC) 3296 is called
"mineral wool," this classification includes a variety of mineral fiber
products such as mineral wool, fibrous glass wool, fiber board, and
accoustical tile. The United States Department of Commerce Census of
Manufacturers does not report production data specific to the mineral
wool manufacturing industry as defined in this study. The Mineral Insu-
lation Manufacturers Association considers mineral insulation to include
fibrous glass wool and does not maintain current production data.
The largest United States manufacturer of mineral wool insulation
was reported to have had sales of approximately $35 to $37 million in
3
1976, and the second largest producer had sales totalling about $20 million.
Total mineral wool insulation sales were on the order of $175 million per
year during the 1972 to 1974 period with about 65 percent coming from
sales of structural insulation and the remaining 35 percent being sales
4-6
-------
4
of industrial and equipment insulation. Industry sources report that
total mineral wool sales were approximately $80 to $100 million in 1976.
According to reported market research data, sales have grown since the
early 1960's at an annual rate of only 3 percent in constant dollars.
During the years 1972 to 1974, mineral wool insulation shipments
were estimated to be about 600 million pounds, growing at an annual rate
of less than 2 per cent. This compares to an annual growth rate of 17
percent for fibrous glass insulation ove,r the 1960 to 1974 period.
Although shipments of mineral wool grew slightly during the early 1970's,
mineral wool has steadily lost its share of the thermal insulation market
to fibrous glass and cellulose. Tables 4-2 through 4-4 show the quantity
and value of insulation shipments in 1976 and the distribution of demand
for insulating materials.
4.2.2 Projected Demand for Insulation
The demand for insulation has historically followed the general
economic cycle since the majority of insulation materials have been used
in the construction of new housing and industrial process equipment. The
oil embargo of 1973 - 1974 and the following OPEC price escalations
resulted in increased energy conservation measures on existing
structures. Increased consumer demand, coupled with a strike at a major
fibrous glass wool manufacturer, resulted in spot shortages of structural
insulation during the mid-1970's. As a result of these shortages, the
insulation industry committed itself to major expansions in production
capabilities to meet the anticipated demand for energy conservation
products. Following the severe winter of 1976 - 1977, expectations of
increased demand were heightened by the 1977 income tax credit for energy
4-7
-------
Table 4-2. Insulation Industry Shipments by Material, 1976
8
Insulating
Material
Estimated Shipments of Structural
Insulating Material
Quantity
(Ibs x 1QQ )
Value
( $ x 1Q6 )
Fiber glass
Rock wool
Cellulose
1,400
400 - 500
600
470
80 - 115
65
Table 4-3. Demand for Insulation by Material'
Industrial equipment and pipes
Building construction
New residential
Reinsulation/remodel ling
Commercial/industrial
Fiber Glass
Rock Wool
Cellulose
35%
65%
35%
20%
10%
30%
70%
25%
15%
30%
10%
90%
10%
75%
5%
Table 4-4. Building Construction Insulation Demand
10
New residential construction
Reinsulation and remodelling
Commercial and industrial
building
* Less than 0.5%
Fiber Glass
Rock Wool
Cellulose
Total
90%
65%
65%
10%
15%
35%
*
20%
*
100%
100%
100%
4-8
-------
conservation expenditures on existing homes. Also at this time, the
Department of Housing and Urban Development (HUD) announced the Minimum
Property Standards which specify thermal insulation efficiencies for new
housing.
At the time of the tax credit proposal in April 1977, several
government agencies were concerned that legislative efforts could be
hampered by a lack of precise data on the supply of insulation.
Although existing statistical data indicated there was an adequate
supply of storm doors and windows, there were little data available on
the present and future production capability of thermal insulation
manufacturers.
ICF, Incorporated (ICF), under contract to the Federal Energy
Administration, conducted an analysis of the United States insulation
industry in order to estimate current and planned industry capacity and
potential insulation demand in light of the pending tax credit for
energy-conserving investments. ICF had only 10 calendar days to complete
this work, and conducted extensive interviews with insulation industry
associations, company officials, and financial analysts in June of 1977.
ICF estimated that mineral wool capacity would increase less rapidly
than fiber glass capacity over the next 4 to 7 years and that cellulosic
insulation capacity would increase more rapidly. According to their
estimate, mineral wool capacity could increase by 10 percent per year
through 1979 and 7 percent thereafter. Total mineral wool capacity
could total 1.3 billion pounds in 1985, as shown in Figure 4-1. ICF also
reported that all insulation producers were undertaking or planning
4-9
-------
Figure 4-1.
5000
4000
3500
300C
o
r-l
X
2500
O 2000
»c
5!
u
15CO
1000
500
Estimated Structural Insulation Oi; jc i_tv,
1976-1935
77 73 79
91 82
YEAR
4-10
-------
capacity increases in 1977 and that mineral wool manufacturers were
13
operating near capacity at the time of the study.
ICF concluded that there would appear to be no shortage of
insulation capacity for retrofit purposes after 1977. At full capacity
in 1977, enough insulation could be supplied to retrofit 4.6 million
homes per year at "average" retrofit levels. Demand for retrofit in 1977
was variously estimated at 2 to 3 million homes without a tax credit. An
additional 1 to 4 million homes could be added as a result of a tax
credit.15
At the same time as the ICF analysis, a similar study was undertaken
by the Office of Business Research and Analysis (OBRA) of the United
States Department of Commerce. OBRA mailed a questionnaire to producers
of insulation materials and received responses from an estimated 95
percent of the industry. The capacity figures reported include
production capacity as of January 1, 1977, plus financially approved
expansion plans through January 1, 1980, and proposed expansion plans
with no financial commitment.
Fiber Glass Batts and Blankets
Capacity: January 1, 1977 January 1, 1980
Million Square Feet Million Square Feet
of R-ll Equivalent of R-ll Equivalent
8,318 11,270
Loose Fiber
January 1, 1977 January 1, 1980
Million Square Feet Million Square Feet
of R-19 Equivalent of R-19 Equivalent
535 820
4-11
-------
Cellulose
Capacity:
January 1, 1977
Obs)
1,677,648,000
January 1, 1980
Obs)
4,896,384,000
Mineral Wool
Capacity:
Batts and Blankets
January 1, 1977 January 1, 1980
Million Square Feet Million Square Feet
of R-ll Equivalent of R-ll Equivalent
917 1,197
Loose Fiber
January 1, 1977 January 1, 1980
Million Square Feet Million Square Feet
of R-19 Equivalent of R-19 Equivalent
491 851
Based on the information obtained from the completed questionnaires and
an analysis of the existing housing inventory, new construction starts
and the construction materials industry, OBRA estimated that there were
approximately 25.5 mil Ion housing units in 1977 that could be improved
by adding additional insulation. The then existing industry capacity
and committed expansion would provide sufficient thermal insulation
materials to insulate these housing units by 1981 if retrofit was
restricted to attics only or by 1983 if walls as well as ceilings were
upgraded. Tables 4-5 and 4-6 show the housing units which could be
insulated through 1982 with existing and committed capacity expansion.
There is little agreement in the industry as to the actual number
of housing units that require additional insulation to meet current
4-12
-------
Tabl e 4-5 —Existing Capacity and Approved/Committed Capacity Expansion for Supply of
Insulation Materials for One- To Four-Family Housing Units (Attic/Ceiling and Sidewall Insulation)
(Thousand Units)
ousing inventory to be insulated at
beginning of period
ew starts (one-four family units) ....
lobile homes
umber of homes that can be
Insulated1
Total
umber of homes that can be retrofitted
after subtracting requirements of new
housing starts
•lance of units left to be insulated ....
1977
25.500
e1 900
"300
2 2 555
3484
4987
5 237
663
7 79
4405
2,205
23.295
1978
23,295
"1,900
e350
*2.819
3 499
4 1,562
5239
«67
779
5,265
3,015
20,280
1979
20,280
"2,000
"4OO
23,529
3513
42,148
5 240
668
780
6,578
4,178
16,102
1980
16,102
* 2,000
e400
23,750
3513
4 2,880
5240
669
780
7,532
5,132
10,970
1981
10,970
"2,000
"400
23,750
3513
4 2,880
5240
«69
780
7,532
5,132
5,838
1982
5,838
"2,000
"4OO
2 3, 750
3513
42,880
5 240
669
780
7,532
5,132
706
*The materials listed In the columns ware combined In some Instances with urea formaldehyde (UF) foam to arrive at the number of homes that
Mild be Insulated. Since UF foam is used only for sldewall Insulation, the other materials were presumed to provide the corresponding attic Insula-
on In each housing unit.
'fiber glass and UF foam (1977-82) 3rock wool 4cellulose and UF foam (1979-82) 'aluminum multi-layered reflective
ill and UF foam (1979-82) 6perlite loose fill and UF foam (1979-82) 7vermlcullte loose fill and UF foam (1979-82)
• - estimate
Tab] 6 4-6 —Existing Capacity and Approved/Committed Capacity Expansion for Supply of
Insulation Materials for One-Family Housing Units (Attic/Ceiling Insulation Only)
(Thousand Units]
outing inventory to be insulated at
beginning of period
ew starts (one-family units)
otaile homes
umber of homes that can be insulated1
Total
umber of homes that can be retrofitted
after subtracting requirements of new
bousing starts and mobile homes
ilince of units left to be insulated
1977
20,700
"1,400
"300
23050
3 767
4 1,678
«237
663
779
5 874
4 174
16 526
1978
16,526
"1,400
"350
23 443
3 791
42,656
5239
«67
779
7 275
5 525
11 001
1979
11 001
e1 400
"400
24 188
3813
43,470
5240
668
780
8059
7 059
3Q4?
1980
3 942
"1 400
"400
24 538
3813
43,557
S240
6 69
780
97Q7
7 4Q7
materials listed In the columns were combined in some Instances with urea formaldehyde (UF) foam to arrive at the number of homes that
Mild be Insulated. Since UF foam is used only for sldewall Insulation, the other materials were presumed to provide the corresponding attic intula-
SlBIn each housing unit.
%Iber glass and UF foam 3rock wool ^cellulose 5a|uminum multi-levered reflective foil 6-
'dniculite loose fill
• estimate
perlite loose fill
Source: ref. 17
4-13
-------
thermal efficiency standards because the level of existing insulation is
not known. In 1977, estimates ranged from less than 25 million to more
19
than 40 million homes. Even the 25 million estimated could be over-
stated if many homeowners in the more temperate regions of the country do
not choose to install additional insulation. It is important to keep in
mind that the ICF and Department of Commerce growth estimates were based
on expectations of high demand. The purpose of these studies was to
estimate the maximum possible expansion of the insulation industry in the
presence of high demand and a tax credit.
4.2.3 The Current Insulation Market
Present market conditions indicate that the demand for insulation
materials which was anticipated in 1977 has not developed. The tax
credit as enacted allows for a credit of 15 percent of the total energy
conservation expenditure; the maximum credit is $300 for each residence.
Industry sources report that only 12 percent of the income tax returns
for 1978 request credit for installation of any type of energy conserving
products (insulation, storm doors and windows, caulking, furnace burners,
20
etc.). This includes all claims in the period from April 20, 1977, to
December 31, 1978. Although the mineral insulation (mineral wool and
21
fibrous glass) industry has expanded about 35 percent since 1977,
present mineral wool production is about 60 percent of capacity.
Retrofit of insulation still only consumes a small portion of mineral
wool production with the remainder being used in new housing and
industrial applications. Apparently, the existing tax credit has not
provided sufficient incentive to homeowners to retrofit at the rates
previously assumed. Consumers most inclined to insulate and those most
receptive to the economics of installing additional insulation have
4-14
-------
already retrofitted their homes. The existing tax credit has not made
the addition of thermal insulation economically attractive to the
remaining homeowners.
4.2.4 Estimated Industry Expansion
As previously stated, the mineral wool industry is currently
operating at about 60 percent of capacity. If the insulation market was
to improve significantly, existing industry capacity could supply
sufficient thermal insulation to meet any foreseeable demand. It was
shown in Section 4.2.2 that the estimated 25.5 million housing units
needing insulation improvement could be supplied with materials from
existing industry capacity within 6 years, assuming new housing starts
will average 2 million units annually. If new housing starts decrease
due to increasing interest rates on home mortgages, each 1 percent drop
in new housing starts will make enough insulation available for 50,000
22
additional retrofit installations.
While higher energy costs may eventually result in greater retrofit
activity, it is not likely that significant expansion of the mineral wool
industry would occur since retrofit activity of this magnitude would be
short-lived. If spot shortages of insulation materials were to occur,
this demand could most quickly be met by cellulosic insulation manu-
facturers. Because the technology needed to produce cellulose insulation
is rather simple and the capital requirements are not high, the industry
is subject to easy entry. During a period of high demand in 1977, it was
reported that 10 to 12 manufacturers of cellulose insulation were
23
entering the business every month. However, the demand for cellulose
products could be restrained if the materials are perceived by consumers
4-15
-------
to be less desirable because of quality problems such as fire retardancy
and vermin resistance. The availability of boric acid, which is used as
a fire retardant, could also constrain the expansion of cellulosic
insulation production.
Despite the existing lack of increased demand for insulating
materials, it is still possible that the capacity equivalent of one
new mineral wool plant could be constructed in the next 5 years.
Expansion by more than one plant is not considered likely at this
time. Both raw materials and finished products are bulky, making it
economically attractive for plants to locate either near a source of
raw materials or product demand. A new plant could conceivably be
built in an area of the country where regional competition was not great.
Even though national production capacity for insulation far exceeds
current demand, a new mineral wool plant could compete for the existing
market in some areas of the United States.
Existing mineral wool plants without batt-producing capabilities
could be modified to produce batts, but this is not considered likely
due to current market conditions and existing production capacities.
Existing plants might also add an entire production line, but due to
nonutilization of present production capacity, this is not likely to
occur unless demand for insulation increases significantly.
Demand for mineral wool insulation could increase if the Federal
Government enacts more stringent legislation on the thermal efficiencies
of new residential and commercial buildings. Reportedly, the Department
of Energy will propose Building Energy Performance Standards in late
1979. These standards will be an extension of HUD's Minimum Property
4-16
-------
Standards, and the "goals" of these standards could be met by existing
24
insulation manufacturing capabilities.
4.3 PROCESS DESCRIPTION
Today, very little pure rock wool or slag wool as such is
manufactured. Only one plant in this country is reported to use natural
rock as the primary raw material. A combination of slag and rock
typically constitutes the charge to the furnace. Approximately
70 percent of the mineral wool sold in the United States is manufactured
25
from blast furnace slag. Most of the remainder is produced using
copper, lead, or phosphate slag.
In a typical mineral wool manufacturing plant, the raw material
(slag and rock) is loaded into a cupola in alternating layers with coke.
As the coke is ignited and burned, the mineral charge is heated to the
molten state at a temperature of 2400 to 3000°F- Combustion air is
supplied through tuyeres located near the bottom of the furnace. This
air is enriched with oxygen in some processes. Auxiliary burners fired
with natural gas may also be used to reduce the consumption of coke.
The molten mineral charge exits the bottom of the cupola in a
water-cooled trough and falls onto a fiberization device. Most of the
mineral wool produced in the United States is made by variations of two
fiberization methods. The Powell process, as shown in Figure 4-2, uses
groups of rotors revolving at a high rate of speed to form the fibers.
Molten material is distributed in a thin film on the surfaces of the
rotors and then is thrown off by centrifugal force. Small globules
develop that trail long, fibrous tails as they travel horizontally. Air
or steam may be blown around the rotors to assist in fiberizing the
4-17
-------
material. A second fiberization method, the Downey process (shown in
Figure 4-3), uses a spinning concave rotor with air or steam attenuation.
Molten material is distributed over the surface of the rotor where it
flows up and over the edge to be caught up in a high velocity stream of
air or steam. The configuration of the rotor varies from process to
process and may spin either in a vertical or horizontal plane. The point
at which the molten stream contacts the rotor can also vary.
During the spinning process, not all the globules that develop are
converted into fiber. The non-fiberized globules that remain are
referred to as "shot." In raw mineral wool, as much as half of the mass
25
of the product may consist of shot. Shot is usually separated from
the wool by gravity immediately following fiberization. Some of this
waste has reportedly been used in sandblasting but, in general, it
?fi
represents a disposal problem for mineral wool producers. Commercial
standards for mineral wool insulation generally limit the maximum shot
content of the material since shot is a poor insulator which takes up
space that could be better utilized if occupied by air.
Various chemical agents may be applied to the newly-formed fiber
immediately following the rotor. In almost all cases, an oil is applied
to suppress dust and, to some degree, anneal the fiber. This oil can
either be a proprietary product developed for this use or a medium weight
fuel or lubricating oil. If the fiber is intended for use as loose wool
or bulk products, no further chemical treatment is necessary. Where the
mineral wool product is required to have structural rigidity, as in batts
and industrial felt, a binding agent is applied with or in place of the
oil treatment. This binder is typically a phenol- formaldehyde resin
4-18
-------
ROTOR
MOLTEN STREAM
DISTRIBUTOR
f^*f >^
BINDER *-'
ANNULAR
AIR STREAM
SOURCE: Reference 27
FIGURE 4-2. POWELL PROCESS
CONCAVE ROTOR
v __ - ~-c
BINDER
c~^:'- >^~ •-*•• •="
"DEFLECTING PLATE
FIGURE1 4-3. DOWNEY PROCESS
4-19
-------
that requires curing at elevated temperatures. Both the oil and the
binder are applied by atomizing the liquids and spraying the agents to
coat the air-borne fiber.
After formation and chemical treatment, the fiber is collected in a
blowchamber. Resin and/or oil-coated fibers are drawn down on a wire
mesh conveyor by fans located beneath the collector. The speed of the
conveyor is set so that a wool blanket of desired thickness can be
obtained.
Mineral wool containing the binding agent is carried by conveyor to
a curing oven where the wool blanket is compressed to the appropriate
density and the binder is baked. Hot air, at a temperature of 300 to
600°F, is forced through the blanket until the binder has set. Curing
time and temperature depend on the type of binder used and the mass rate
through the oven. A cooling section follows the oven where blowers
force air at ambient temperatures through the wool blanket.
To make batts and industrial felt products, the cooled wool blanket
is cut longitudinally and transversely to the desired size. Some
insulation products are then covered with a vapor barrier of aluminum
foil or asphalt-coated kraft paper on one side and untreated paper on
the other side. The cutters, vapor barrier applicators, and conveyors
are sometimes referred to collectively as a batt machine. Those
products that do not require a vapor barrier, such as industrial felt
and some residential insulation batts, can be packed for shipment
immediately after cutting. A wire mesh covering may be applied by hand
to some special industrial insulation products.
4-20
-------
Loose wool products consist primarily of blowing wool and bulk
fiber. For these products, no binding agent is applied, and the curing
oven is eliminated. For granulated wool products, the fiber blanket
leaving the blowchamber is fed to a shredder and pelletizer. The
pelletizer forms small, 1-inch diameter pellets and separates shot from
the wool. A bagging operation completes the processes. For other loose
wool products, fiber can be transported directly from the blowchamber to
a baler or bagger for packaging. Figure 4-4 shows the typical mineral
wool process flow diagram.
Adoption of new technical innovations in the mineral wool industry
has been slow. One plant currently in operation uses a reverberatory
furnace instead of a cupola for the melting of slag and rock. Electric
furnaces have received considerable attention as possible substitutes for
cupolas, but none are currently in operation in the United States.
However, a single line mineral wool plant currently under construction in
28
Woodbridge, Virginia, is reportedly installing an electric furnace.
Although the use of electric furnaces would reduce the air pollution
problems associated with cupolas, there has been difficulty in developing
a commercially viable refractory lining that can resist the corrosive and
29
erosive effects of slag in continuous melting operations.
4-21
-------
BATT LINE
Exhaust
-I
Exhaust
Exhaust
I
Exhaust
Slag
Rock
and
Coke
.; Cupola
_Blowchamber ; . _.>.j Curing Oven . =..; Cooler
Batt
Machine
Shipment
Tuyere Air
Binder
Vapor Barrier
ro
ro
WOOL LINE
Slag
Rock.
and
Coke
Exhaust
Cupola
Tuyere Air
Exhaust
11
Blowchamber
Oil
Granulator
Bagger
or
Baler
Shipment
FIGURE 4-4. TYPICAL MINERAL WOOL PROCESS FLOW DIAGRAM
-------
REFERENCES
1. Pundsack, F. L. Fibrous Glass - Manufacture, Use, and Physical
Properties In Occupational Exposure to Fibrous Glass - Proceedings of a
Symposium. Washington, D. C. Department of Health, Education, and
Welfare (HEW). HEW Publication Number (NIOSH) 76-151. April 1976.
Page 12.
2. Reference 1.
3. ICF, Incorporated. Supply Response to Residential Insulation
Retrofit Demand. Report to the Federal Energy Administration. Contract
Number P-14-77-5438-0. Washington, D. C. June 17, 1977. Page 10.
4. Reference 3.
5. Reference 3.
6. Reference 3.
7. Reference 3, Page 11.
8. Reference 3, Page 12.
9. Reference 3, Page 26.
10. Reference 3, Page 27.
11. Reference 3, Page 18.
12. Reference 3, Page 19.
13. Reference 3, Page 17.
14. Reference 3, Page 20.
15. Reference 3, Page 3.
16. Penoyar, W. E., and F. E. Williams. Survey of United States
Residential Insulation Industry Capacity and Projections for Retorfitting
United States Housing Industry. United States Department of Commerce.
Washington, D. C. Draft to appear in Construction Review. August/
September 1977. Page 5.
17. Reference 16, Page 9.
18. Reference 16, Page 10.
4-23
-------
19. Reference 16, Page 9.
20. Telecon. S. Matthews, Rockwool Industries, and R. Rosensteel, United
States Environmental Protection Agency. May 11, 1979. Production and
capacity of the mineral wool manufacturing industry.
21. Telecon. S. Cady, Mineral Insulation Manufacturers Association, with
L. Anderson, United States Environmental Protection Agency. June 28,
1979. Growth of the mineral wool manufacturing industry.
22. Reference 3, Page 34.
23. Reference 3, Page 34.
24. Telecon. H. Major, Department of Energy, with L. Anderson, United
States Environmental Protection Agency. July 10, 1979. Growth of the
insulation industry and building energy performance standards.
25. Fowler, D.P. Industrial Hygiene Surveys of Occupational Exposure to
Mineral Wool. Draft Report. National Institute of Occupational Safety
and Health (NIOSH). Cincinnati, Ohio. Report of NIOSH Contract
Number 210-76-0120. June 1978. Page 2.
26. Reference 25, Page 4.
27. Reference 1, Page 14.
28. Telecon. L. Anderson, United States Environmental Protection Agency,
with W. Millard, Virginia State Air Pollution Control Board. November 1,
1979. Mineral wool plants operating in Virginia.
29. Cobble, J., and J. Hansen. Evaluation of Refractories for Mineral
Wool Furnaces. Bureau of Mines. Tuscaloosa, Alabama. Report of
Investigation 8090. December 1975.
4-24
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5. AIR EMISSIONS DEVELOPED IN THE SOURCE CATEGORY
5.1 PLANT AND PROCESS EMISSIONS
This chapter identifies the types and quantities of emissions from
several potential emission points within a typical mineral wool
manufacturing plant. Cupola and blowchamber emissions are common to
essentially all mineral wool plants. Emissions from other process points
such as curing ovens and coolers occur when this equipment exists in the
plant configuration and is being used to manufacture products requiring
their operation. In the discussion which follows, emission data and
1 2
emission factors from traditional sources have been compiled. '
References 1 and 2 will be referred to as AP-40 and AP-42, respectively,
throughout the remainder of Chapters 5 and 6. In addition, emission test
data were requested from the majority of local and State control agencies
naving jurisdiction over existing mineral wool plants. The agencies for the
States of Indiana, Missouri, and Alabama and the South Coast Air Quality
Management District of California furnished data for this study.
Emission data from the open literature and test data from control
agencies were compiled and then calculations were performed as necessary
to reduce the data to pollutant concentrations and emission factor
format. In the discussion that follows, a test point usually is an
average of three tests for the emission source. Generally, emission
factors were estimated by using previously reported data; e.g., from
5-1
-------
AP-40, plus the data obtained during this study to calculate average
emission factors based on all available data. Exceptions to this general
procedure will be noted in the test.
5.1.1 Furnace Emissions
Mineral wool is manufactured using cupolas as the melting furnace
at most plants in this country. One plant has a reverberatory furnace
supplying mineral wool fiber to several parallel processing lines. A
plant using an electric melting furnace is expected to be in operation
in 1980. Since cupolas are by far the most common furnace in the industry,
as would be expected, the majority of furnace test data describes cupola
emissions.
5.1.1.1 Particulate Emissions - Table 5-1 contains a summary of
uncontrolled particulate emission data that is reported in AP-40 as well
as data that were assembled during this source category survey. The
uncontrolled emission factor reported in AP-42 is 11 kg/Mg (22 Ibs/ton)
which is apparently based upon the 3 cupola emission tests reported in
AP-40 which are summarized on the first line in Table 5-1.
The uncontrolled emission factor for cupola particulate emissions
used in this study to estimate typical plant emissions as well as total
national emissions for the industry is an average of the AP-40 data plus
the three additional tests obtained during this source category survey.
The resulting uncontrolled emission factor is 8 kg/Mg (16 Ibs/ton).
The results from only one particle size analysis were available from
the agency data. The test data from an Andersen sampler analysis of
3
uncontrolled particulate from a cupola were:
5-2
-------
Table 5-1. Uncontrolled Particulate Emissions from Mineral Wool Cupolas
Number
nf Tests
Dust Concentration
mg/scm (gr/scf)
Emission Factor
kg/Mg (Ibs/ton)
Range
Average
Range
Average
Reference
1630.0 to 2930.0 2410.0
(0.71 to 1.28) (1.05)
1350.0 to 5250.0 3140.0
(0.59 to 2.29) (1.37)
8.0 to 14.1
(16.0 to 28.2)
2.3 to 6.8
(4.6 to 13.7)
10.8
(21.6)
5.3
(10.6)
11
(22)
AP-40
Present study
AP-42
5-3
-------
Particle size range,pm Percent by weight
+ 30 5.6
9.2 to 30 0.1
5.5 to 9.2 0.5
3.3 to 5.5 1.0
2.0 to 3.3 5.0
1.0 to 2.0 67.8
0.2 to 1.0 20.0
There is one emission test reported in AP-40 for participate emissions
from a reverberatory melting furnace of approximately 2.5 kg/Mg
(5 Ibs/ton) which is also the emission factor reported in AP-42. No
further test data for reverberatory furnaces were obtained during this
source category survey.
5.1.1.2 Sulfur Compound Emissions - The only other emission factor
contained in AP-42 for cupola emissions is that reported for sulfur
oxides. Table 5-2 contains a summary of test data from AP-40 and data
obtained during this source category survey.
The emission factor for sulfur oxides in AP-42 significantly under-
estimates the emissions of sulfur oxides from mineral wool cupolas.
The 0.01 kg/Mg (0.02 Ibs/ton) emission factor seems to be in error since
AP-40 is used as a reference but, as shown in Table 5-2, the one sulfur
oxide data point from AP-40 was reduced to an emission factor and was
found to be much larger than the reported value in AP-42. An emission
factor of 5.5 kg/Mg (11 Ibs/ton) based on the data collected in this
source category survey and the one test result reported in AP-40 was used
to estimate uncontrolled sulfur oxides emissions from mineral wool cupolas.
The one test from AP-40 where the concentration of sulfur trioxide
was identified is worth noting since about 36 percent by weight of the sulfur
oxides were reported to be emitted as sulfur trioxide in this test. This
result is of interest since, as will be discussed later, severe corrosion
5-4
-------
Table 5-2. Average Uncontrolled Sulfur Oxides and Hydrogen Sulfide Emission Concentrations
and Factors for Mineral Wool Cupolas
Sulfur Dioxide
Sulfur Trioxide
Total Sulfur
Oxides
Hydrogen Sulfide
Flue Gas
Concentration
(ppm)
Emission
Factor
kg/Mg (Ibs/ton)
Flue Gas Emission Emission Flue Gas
Concentration Factor Factor Concentration
(ppm) kg/Mg (Ibs/ton) kg/Mg (Ibs/ton) (ppm)
Emission
Factor
kg/Mg (Ibs/ton)
Reference
Ul
en
• w
430
86 to 1120
500
_ _
5.5 (11.1)
5.3 (10.6)
•••
200
—
•» —
3.2 (6.3)
—
0.01 (0.02)
8.7 (17.4)
5.3 (10.6)
— _
--
150 to 500
_.»
—
1.5 (3.0)
AP-42*
AP-40**
Present study**
SIP****
**
***
****
Test results upon which emission factor is based could not be identified.
One test value for S02 and $03 available from this source.
Ten test results for sulfur dioxide and three tests for HgS were obtained during this study.
One agency having jurisdiction over a mineral wool plant has an emission standard for S02, a maximum concentration
of 500 ppm.
-------
problems in the baghouse structures were observed at several of the
plants visited during the study.
There were three tests in which hydrogen sulfide emissions from
mineral wool cupolas were reported. Two tests from a Canadian study
showed concentrations of about 150 and 190 ppm hydrogen sulfide with
emission factors of 0.4 (0.8) and 0.5 kg/Mg (1.0 Ibs/ton), respectively,
4
for two tests. Additionally, one test for a United States plant was
reported where the flue gas concentration was 500 ppm with a 3.6 kg/Mg
5
(7.14 Ibs/ton) hydrogen sulfide emission factor. An average of these
three tests was used to estimate emissions from both a typical mineral
wool plant as well as to estimate national emissions, the resulting
emission factor being equal to 1.5 kg/Mg (3.0 Ibs/ton).
5.1.1.3 Carbon Monoxide Emissions - There are significant amounts of
carbon monoxide produced by mineral wool cupolas although neither AP-40
nor AP-42 report test data or an emission factor for this pollutant.
There were a total of nine tests that were obtained for uncontrolled
carbon monoxide emissions from mineral wool cupolas during this study.
As can be seen in Table 5-3, there is a wide range of both carbon
monoxide concentration in the flue gas and emission factor values. This
wide range may be explained in part by various amounts of dilution air
entering the cupola exhaust systems from plant to plant and possibly by
the various analytical methods used to test for carbon monoxide. Some of
the values were developed by Orsat analysis while other results were
based on highly sophisticated gas chromatographic analytical techniques.
5-6
-------
Table 5-3. Uncontrolled Carbon Monoxide Emissions from Mineral Wool Cupolas
Number of
Tests
Flue Gas Concentration (ppm)
Range Average
Emission Factor
kg/Mg (Ibs/ton)
Range Average
Reference
1,000 - 83,000
23,400
3 - 156 (6 - 312) 78 (156)
Present study
01
Table 5-4. Uncontrolled Nitrogen Oxides Emissions from Mineral Wool Cupolas
Number of
Tests
Flue Gas Concentration (ppm)
Range Average
Emission Factor
kg/Mg (Ibs/ton)
Range Average
Reference
13 - 125
39
0.1 - 1.9 (0.2 - 3.7) 0.8 (1.6) Present study
-------
For the estimate of typical plant and national emissions of carbon
monoxide, an emission factor of 78 kg/Mq (156 Ibs/ton) was used. This
factor is an average of nine test results collected during this source
category survey.
5.1.1.4 Nitrogen Oxides Emissions - For six emission tests obtained
from the control agencies, nitrogen oxides were analyzed and reported for
cupola exhaust gases. This data is summarized in Table 5-4. The average
of these tests, an emission factor of 0.8 kg/Mg (1.6 Ibs/ton), was used
to estimate typical plant and national emissions for mineral wool
manufacturing.
5.1.2 Blowchamber Emissions
Most mineral wool plants have a blowchamber immediately following
the fiberizing step in the process. The exhaust gas from the blowchamber
fans is usually treated by a control device to remove entrained flywool
or lint before it is exhausted to the atmosphere.
5.2.1.2 Blowchamber Particulate Emissions - Table 5-5 contains
uncontrolled dust concentration and emission factor data for mineral wool
blowchamber exhausts. The AP-42 uncontrolled emission factor of 17
Ibs/ton could also be related to the AP-40 data just as it could for the
cupola emission factor. The emission factor used for blowchamber
emission estimates in this study is a value of 6 kg/Mq (12 Ibs/ton).
This factor is based upon the overall average of the four tests from
AP-40 and the two test results obtained from control agencies during
this study.
5.1.2.2 Blowchamber Volatile Organic Compound Emissions - The only
pollutants other than particulate that were identified as being emitted
from mineral wool blowchambers from the literature and this source
5-8
-------
Table 5-5. Uncontrolled Particulate Emissions from Mineral Wool Blowchambers
Dust Concentration Emission Factors
Number mg/scm (gr/scf)
of Tests Range Average
4 121 -
(0.053
2 22.2 -
(0.0097
914
- 0.399)
24.0
- 0.0105)
298
(0.13)
23.1
(oioioi)
kg/Mg (Ibs/ton)
Range Average
1.3
(2.6
0.7
(1.4
- 27.8
- 55.6)
- 0.9
- 1.8)
8.6
(17.2)
0.8
(1.6)
17
Reference
AP-40
Present study
AP-42
-------
category survey are volatile organic compounds (VOC). An annealing
oil is applied to mineral wool at the point where fibers are formed to
control flywool generation. When batts are manufactured, a resin is
applied in place of, or in addition to, the oil. This resin may
contribute to VOC emissions. The relatively low temperatures in blowchamber
exhaust streams of about 180°F might result in condensation of the oils
and binders and thereby emission to the atmosphere as particulate matter.
Two test results, both from the same plant, were obtained during this
study; the result of these two tests is an average of 0.2 kg/Mg
(0.4 Ibs/ton) of total VOC, reported as methane. One result is reported
in AP-40 for a test of aldehydes in the exhaust from a mineral wool
blowchamber; this result is an emission factor of 0.86 Ibs/ton as total
aldehydes.
Since data was reported using different bases, the higher test
result or an emission factor value of 0.45 kg/Mg (0.9 Ibs/ton) of VOC
as aldehydes from the blowchamber was used in this study to make typical
plant and national VOC emission estimates for mineral wool manufacturing.
5.1.3 Curing Oven Emissions
The available test results for uncontrolled particulate emissions
from mineral wool curing ovens are reported in Table 5-6. The average
emission factor estimate using the AP-40 values is 2 kg/Mg (4 Ibs/ton)
which was used to make typical plant and national emissions estimates for
particulate matter from mineral wool manufacturing. This is the same
emission factor reported in AP-42 for this source.
Total VOC results were not reported in the data reviewed, but tests
for aldehydes were reported in AP-40 for the inlet and outlet in two
afterburner tests. The two reported inlet values were used to calculate
an average emission factor of 0.5 kg/Mg (1 Ibs/ton) for uncontrolled
5-10
-------
Table 5-6. Uncontrolled Participate Emissions from Mineral Wool Curing Ovens
Number
of Tests
Dust Concentration
mg/scm (gr/scf)
Range Average
Emission Factor
kg/Mg (Ibs/ton)
Range Average
Reference
275 - 961 484
(0.12 - 0.42) (0.21)
0.75 -
(1.50 -
2.95 1.82
5.9) (3.63)
2
(4)
AP-40
AP-42
5-11
-------
aldehydes from a mineral wool curing oven. This emission factor was
used to make VOC emission estimates for a typical plant as well as
nationwide emissions.
Two test results for nitrogen dioxide emissions from curing ovens
are reported in AP-40 at the inlet to afterburners used for control of
VOC emissions. The average of these two tests is a 0.08 kg/Mq (0.16 Ibs/
ton) emission factor; this factor was used to estimate oxides of nitrogen
emissions from an uncontrolled curing oven.
5.1.4 Mineral Wool Cooler Emissions
There were no data obtained for emissions from mineral wool coolers
during the source category survey other than four tests for particulates
contained in AP-40. These test result in an average emission factor of
about 1 kg/Mg (2 Ibs/ton) which is also the emission factor reported in
AP-42. The 1 kg/Mg emission factor was used to make subsequent emission
estimates of particulate matter for a typical plant and nationwide
emissions.
For one of the four emission tests noted above, a test for total
aldehydes was conducted. The result of this test is an emission factor
estimate of 0.02 kg/Mg (0.04 Ibs/ton) of total aldehydes which was used
to make typical plant and nationwide VOC emission estimates.
5.1.5 Asphalt Application
Asphalt vapors can be emitted during application of the asphalt
film to the paper backing used when manufacturing insulation batts. These
emissions reportedly can be reduced by proper temperature control of the
application process. An asphalt applicator was operating at only one
plant visited during this source category survey; no visible emissions
5-12
-------
were apparent while observing this operation. No emission test data
for this operation were obtained from either the literature or the
agencies contacted during this study. For these reasons, this emission
source was not further considered during the study.
5.2 UNCONTROLLED ANNUAL EMISSIONS FOR A TYPICAL MINERAL WOOL PLANT
A typical mineral wool manufacturing plant was assumed to consist
of two cupola lines with each line having the following production rates:
Cupola charging rate - 2.73 Mg/hour (3 tons/hour) with 8400
operating hours/year
Blowchamber - 1.64 Mg/hour (1.8 tons/hour) with 8400 operating
hours/year.
The cupola production rate is approximately the average and median
rate for the mineral wool industry in late summer of 1979. The
blowchamber operating rate assumes a 60 percent conversion of cupola
charge to usable fiber. One of the lines is also assumed to have
a curing oven and cooler with a production rate of 1.64 Mq/hour
(1.8 tons/hour) which operates for 4200 hours/year. It is assumed that
this line manufactures blowing wool when batts are not being manufactured.
Table 5-7 contains a compilation of all of the emission factors used
to make the emissions estimate for a typical plant and for the industry.
Table 5-8 contains the annual uncontrolled emissions from a typical
mineral wool plant operating at the specified conditions.
The emissions from a typical mineral wool plant controlled to meet
the requirements of a typical SIP are contained in Table 5-9. The
only standard from a SIP that can be considered to apply to mineral wool
plants is the process weight regulation for particulates where
5-13
-------
Table 5-7. Uncontrolled Emission Factors for Mineral Wool Manufacturing - kg/Mg (Ibs/ton)
in
Process
Source
Cupola
Blowchamber
Curing Oven
Cooler
Table 5-8.
Process
Source
Cupola
Blowchamber
Curing Oven
Cooler
Particulates
8 (16) 5.
6 (12)
2 (4)
1 (2)
Uncontrolled Potential
Particulates
Sulfur
Oxides
5 (11)
—
—
— —
Emissions
Sulfur
Oxides
366 (403) 252 (277)
165 (181)
14 (15)
7 (8)
--
—
—
Hydrogen
Sulfide
1.5 (3.0)
—
—
— —
from a Typical
Hydrogen
Sulfide
69 (76)
—
—
—
Carbon
Monoxide VOC
78 (156)
0.45 (0.9)
0.5 (1.0)
0.02 (0.04)
Mineral Wool Manufacturing Plant -
Carbon
Monoxide voc
3,570 (3,930)
12 (14)
3 (4)
< 1 «1)
Nitrogen
Oxides
0.8 (1.6)
—
0.08 (0.16
** **
Mg/yr (tons/yr)
Oxides of
Nitrogen
37 (40)
—
1 (1)
—
TOTALS 552 (607)
252 (277)
69 (76)
3,570 (3,930) 15 (18)
38 (41)
-------
0 ft?
E = 3.59 p >ot has been found to be typical in this study. Using this
regulation, the controlled emission factors were found to be 1.18 kg/Mg
(2.36 Ibs/ton) for mineral wool cupolas and 1.43 kg/Mg (2.87 Ibs/ton)
for mineral wool blowchambers and curing ovens. Although some States
regulate sulfur dioxide emissions with regulations in the range of 500
to 2000 ppm, these concentrations are in excess of most cupola flue gas
concentrations of sulfur dioxide reviewed in this study. Therefore, the
SIP's were not considered to result in reduction of mineral wool sulfur
oxides emissions.
5.3 TOTAL NATIONWIDE EMISSIONS FROM MINERAL WOOL MANUFACTURING
Total potential nationwide emissions for the mineral wool
manufacturing industry are contained in Table 5-10. The assumptions
upon which this estimate is based include:
Cupola charge capacity for the mineral wool industry is
estimated to be 1.23 x 10 Mg/year (1.35 x 10 tons/year). This estimate
is based upon individual plant data obtained from NEDS and from the
source category plant visits. Where the cupola charge rate was not
provided or considered confidential, an average plant capacity was
substituted for the unknown value.
The conversion rate from total cupola charge to actual
mineral fiber produced for further processing through the blowchamber
was assumed to be 60 percent. This factor makes allowance for the coke
in the cupola charge and for the "shot" produced from the cupola which
cannot be further processed.
5-15
-------
tn
i
Table 5-9. Potential Emissions from a Typical Mineral Wool Manufacturing Plant
Controlled to Meet a Typical SIP - Mg/year (tons/year)
Process
Source
Cupola
Bl owchamber
Curing Oven
Cooler
Particulates
54
39
10
7
(60)
(43)
(11)
(8)
Sulfur Hydrogen Carbon
Oxides Sulfide Monoxide voc
252 (277) 69 (76) 3,570 (3,930)
12 (14)
3 (4)
< 1 (<1)
Nitrogen
Oxides
37 (40)
—
1 (1)
—
CTl
TOTALS: 110 (122) 252 (277) 69 (76) 3,570 (3,930) 15 (18) 38 (41)
-------
I
I—»
-J
Table 5-10. Nationwide Potential Emissions from the Mineral Wool Manufacturing Industry for 1979
Assuming Compliance with SIP1s - Mg/year (tons/year)
Process
Source
Cupolas
B1 owchamber
Curing Oven
Cooler
Parti culates
1,450 (1,600)
1,040 (1,150)
270 (290)
190 (210)
Sulfur
Oxides
6,750 (7,420)
—
--
—
Hydrogen
Sulfide
1,850 (2,040)
—
—
—
Carbon
Monoxide
95,600 (105,300)
—
—
—
voc
—
330 (360)
150 (170)
15 (17)
Oxides of
Nitrogen
980 (1,080)
— •
25 (27)
—
TOTALS: 2,950 (3,250) 6,750 (7,420) 1,850 (2,040) 95,600 (105,300) 495 (547) 1,005 (1,107)
-------
It was estimated that one-fourth of the plant production for the
industry is processed through a curing oven and cooler. Information
obtained during the source category survey indicated that typically one
production line had a curing oven and cooler that were used about half of
the production schedule on that line.
Baseline control was assumed to apply only to particulate
emissions from cupolas, blowchambers, and curing ovens of a mineral wool
plant.
Baseline control was considered to be emissions in Ibs/hour
0 62
determined from E = 3.59 p , where p is the process weight rate in
tons/hour.
5-18
-------
REFERENCES
1. Danielson, J. A., Editor. Air Pollution Engineering Manual, Second
Edition. Air Pollution Control District, County of Los Angeles,
California. United States Environmental Protection Agency, Research
Triangle Park, North Carolina. Publication Number AP-40. May 1973.
2. Compilation of Air Pollutant Emission Factors, Third Edition.
United States Environmental Protection Agency, Research Triangle Park,
North Carolina. Publication Number AP-42. August 1977.
3. Sinclair, L. S. Report on Fluorides and Particle Size in Cupola
Exhaust Gases Entering Wet Scrubber. San Bernardino Air Pollution
Control District. San Bernardino, California. Engineering Evaluation
Report Number 71-9. February 18, 1971.
4. Powlesland, W. H., C. H. Knight, and J. W. Smith. Dry Catalytic
Removal of Hydrogen Sulphide from Mineral Wool Cupola Flue Gas. The
Fourth International Clean Air Congress. Tokyo, Japan. 1977. Page 757.
5. Memorandum from L. Anderson, United States Environmental Protection
Agency, to J. U. Crowder, United States Environmental Protection Agency.
October 2, 1979. Trip report to Spring Hope Rockwool, Incorporated,
Spring Hope, North Carolina.
6. Reference 1, Page 349.
5-19
-------
6. EMISSION CONTROL SYSTEMS AND ENVIRONMENTAL IMPACT
6.1 CURRENT CONTROL TECHNOLOGY PRACTICES
Several sources of information were utilized to obtain data
describing the application of control technologies to emission points in
the mineral wool process. The data were obtained from discussions with
plant personnel during industry visits, contacts with State and local
control agencies, and summaries from the National Emission Data System
(NEDS). Only the common process emission points - cupolas, blowchambers,
curing ovens, and coolers - were considered in developing this summary of
control technology practices in the industry. Some miscellaneous
sources; e.g., sawing of ceiling tile, mixing of industrial cement, etc.,
were identified in data from the States or NEDS but were usually found in
only one or two plants in the industry.
A summary of the control technologies reported in use for the
mineral wool industry is contained in Table 6-1. The fact that there is
not a one-to-one relationship in Table 6-1 of cupolas to blowchambers is
apparently due to combining cupola product streams at some plants prior
to entry into the blowchamber. As has been stated earlier, there is
usually no more than one curing oven in a mineral wool plant which
accounts for the considerably fewer number of them compared to cupolas.
Presumably, coolers are not considered significant enough of a source to
warrant reporting in most cases.
6-1
-------
Table 6-1. Summary of Air Pollution Controls Operating in the United States Mineral Wool Industry
Number of Process Sources Controlled by Indicated Devices
a\
i
ro
Process
Source
Cupolas3
Blowchambersc
Curing Ovens
Coolers
Total
53
46
15
6
Fabric
Filters
35
2
1
0
ESP
2
0
0
0
Wet
Scrubbers
3
21
0
0
Cyclones
20
3
0
0
Afterburners
2
2
6
1
Lint
Cages
0
9
0
0
Other
2b
0
0
0
None
3
12
8
5
a Two cupolas are controlled with fabric filters followed by direct-flame afterburners; two cupolas are
controlled by wet scrubbers followed by ESP; seven cupolas are controlled by cyclones followed by baghouses;
and one cupola is controlled by a cyclone followed by a wet scrubber.
" Carbon monoxide control system is operating on two cupolas with a baghouse in one plant.
c Three blowchambers use two control devices in series; two plants use afterburners plus wet scrubbers
and one plant has cyclones plus a baghouse.
-------
6.1.1 Cupola Emission Control Systems
6.1.1.1 Control of Participate Emissions - Control of participate
emissions from cupolas has received more emphasis than control of any
other air pollutant from the industry. Table 6-1 shows fabric filtration
as the most commonly applied control technology for mineral wool cupola
particulate emissions. The next most commonly applied control technique
is dry centrifugal collection of particulates emitted from cupolas.
In Table 6-2, emission data have been summarized to illustrate
the effectiveness of the various particulate collectors for control of
cupola emissions. The last line in the table shows the dust concentra-
tion and emission factor that would meet compliance with a typical State
Implementation Plan (SIP) particulate regulation. There are several
plants in the industry which use only cyclones for cupola particulate
emission control. These devices have the capability on occasion to meet
the typical SIP process weight regulation, but compliance is the
exception rather than the rule. There is only one test for a wet
scrubber, but this one result would not comply with the typical SIP. All
of the fabric filtration results demonstrated capability of meeting the
SIP regulation; in fact, the highest test result reported is lower than
the SIP regulation by more than a factor of four.
Corrosion of the baghouse structure or auxilliary equipment was
observed or reported at two plants which were visited during the study.
The corrosion problem experienced at one plant was severe enough to justify
enclosing the baghouse and making provision to heat the area. When climatic
conditions were severe enough, the moisture condensed from the flue gas was
reported to not only "blind" the bags but may literally freeze solid in the bags,
6-3
-------
Table 6-2. Controlled Participate Emissions from Mineral Wool Cupolas
o>
Number Concentration
of Control m9 /scm (gr/scf)
Tests Equipment Range Average
6 Fabric 8.48 to
filter (0.0037
1 Wet
Scrubber
7* Cyclones 192 to
(0.084 to
To comply
with regulation
96.1
to 0.042)
—
641
0.28)
—
46.7
(0.0204)
451
(0.197)
330
(0.144)
286
(0.125)
0
(0
0
(1
Emission Factor
kg/Mg (Ibs/ton)
Range Average
.0022 to 0.35
.0044 to 0.70)
—
.85 to 1.5
.7 to 3.0)
—
0.21
(0.42)
1.1
(2.2)
1.15
(2.3)
1.18
(2.36)
Reference
Present study
Present study
Present study
Typical SIP
* Dust concentration was reported for seven tests, but sufficient data to calculate emission factors were
available for only five of the tests.
-------
according to the plant operator, necessitating replacement of the bags.
At a second plant, there was visible deterioration of exposed metal
surfaces of ducts and baghouse structure after approximately 18 months of
operation. At a third plant, the baghouse was located inside the plant,
but the plant manager reported there had been condensation inside the
baghouse but no resultant corrosion
For the three plants visited but not experiencing serious
corrosion problems, one controlled cupola emissons with cyclones, another
did not have controls operating, and the third was equipped with a
baghouse but reported insignificant corrosion problems, oresumably due to
the relatively mild winter climate.
6.1.1.2 Control of Carbon Monoxide Emissions - One plant in the United
States has an operating system for control of cupola carbon monoxide
emissions. This plant was visited as part of the source category survey and
the following discussion is based upon that visit. The system was
tested in June 1979, and the carbon monoxide concentration based on an
average of two tests was 1,000 ppm. Simultaneous inlet concentrations
were not measured during the 1979 test, but the average inlet
concentration was 70,000 ppm for a July 1977 test. Using these two
different tests, an estimate of the control efficiency for carbon
monoxide would be in excess of 98 percent.
Natural gas and air are injected into some cupolas to supplement
the coke fuel in the charge to the cupola. Control agency personnel
monitored a test about 3 hours in duration to determine if CO emissions
were affected by altering the natural gas and air mixture to a cupola.
The cupola was normally run with natural gas and air flows on. This
6-5
-------
normal condition was followed by a run with the gas flow off and the air
flow on. Then the air, which usually is injected with the gas, was also
turned off. The author concluded that there was no effect upon CO
2
emissions under these various conditions.
6.1.1.3 Control of Sulfur Compound Emissions - There has been a
system reported in operation at a Canadian mineral wool plant for the
o
control of cupola hydrogen sulfide emissions. The control system
consists of a baghouse and hydrogen sulfide removal reactor in series.
The hydrogen sulfide reactor consists of two beds of hematite iron ore
pellets supported by perforated plates; the flue gas can be diverted to
either bed so that an inactive bed can be removed for catalyst
regeneration. Sulfur and dust are recovered from the ore pellets by
screening and are either discarded or recovered for sale. Two tests of
the system have demonstrated hydrogen sulfide removal efficiencies of 85
and 90 percent, respectively. This system also results in reduction of
4
sulfur dioxide emissions by 42 to 75 percent.
A test for evaluation of a pilot baghouse for cupola particulate
control has also shown reduction of sulfur dioxide emissions. Inlet and
outlet S0£ tests of the baghouse demonstrated a 68 percent reduction
in S02 emissions. The apparent explanation for this partial sulfur
dioxide control was the charging of limestone with the normal coke and
slag charge to the cupola.
6.1.2 Blowchamber Emission Control Systems
6.1.2.1 Control of Particulate Emissions - The particulate
emissions from the blowchambers of mineral wool plants are usually
controlled. This fact seems to be due to the nature of these emissions,
6-6
-------
primarily "fly wool;" i.e., fibrous particles that are relatively large,
are readily visible, and can create a nuisance when they accumulate in
the area of the plant. There is also some smoke or haze generated from
the vaporization or decomposition of the annealing oil applied to the
fiber as it is being formed at the spinner. When batts are being
manufactured, there may also be some of the resin emitted as either a
particulate or gaseous decomposition product.
Table 6-1 shows that the most commonly used control devices for
blowchambers are wet scrubbers. The devices that were observed during
this study were low energy scrubbers, generally baffled spray chambers.
When the large fly wool particles are collected in these devices, a
residue builds up which must be automatically removed or cleaned out
manually during process down time.
The next most commonly used device is a simple wire mesh filter
called a screen house, bull cage, or lint cage. This device is simply a
chamber covered with a fine mesh screen through which the blowchamber air
is discharged. The mat of fly wool that builds up on the screen must be
removed manually, usually on a daily basis, sometimes using a water hose
to dislodge the fiber from the screen.
Test data for controlled emissions from blowchambers that have
been reported in AP-40 and test data obtained during this study have been
summarized in Table 6-3. There are relatively few test results avail-
able, but the AP-40 data indicate a scrubber/ESP system, a lint cage, and
a wet scrubber are capable of meeting an SIP standard. The data obtained
during the source category survey indicate that spray chambers and a wet
scrubber could meet the SIP standard. However, a test result for a
6-7
-------
Table 6-3. Controlled Participate Emissions from Mineral Wool Blowchambers
CT)
00
Number
of
Tests
2
1
1
1
1
1
—
Control
Equipment
Spray
chamber
Wet scrubber
+ ESP
Wet scrubber
Lint cage
Wet scrubber
Wet cyclone
To comply with
regulation
Dust Concentration
mg /scm (gr/scf)
Range Average
7.56 to 22.2 14.9
(0.0033 to 0.0097) (0.0065)
25.2
(0.011)
49.4
(0.0216)
27.5
(0.012)
64.1
(0.028)
117
(0.051)
69.1
(0.0302)
Emission Factor
kg/Mg (Ibs/ton)
Range Average
0.39 to 0.65 0.52
(0.78 to 1.3) (1.04)
0.42
(0.84)
0.75
(1.5)
0.55
(1.10)
0.87
(1.74)
4.4
(8.8)
1.44
(2.87)
Reference
Present study
AP-40
Present study
AP-40
AP-40
Present study
Typical SIP
-------
device reported to be a wet cyclone exceeded the SIP on both a dust
loading and emission factor basis.
Two blowchambers at one plant location are reported to use dry
centrifugal collectors to control blowchamber emissions. These cyclones
may be process equipment rather than control devices since cyclones are
commonly used to remove mineral wool from air streams prior to further
processing steps in mineral wool plants. There is a substantial
proportion of blowchambers, 20 percent of the total in this survey, which
are reported to be uncontrolled.
6.1.2.2 Control of Volatile Organic Compound (VOC) Emissions - The only
pollutants in addition to particulates that were identified in Chapter 5
as an emission from blowchambers were VOC's. One plant is reported to
use an afterburner for control of blowchamber emissions although no test
data were obtained for this application. Some reduction of VOC vapor
emissions would be expected if blowchamber gases are controlled with an
afterburner; some reduction of combustible particulate might also be
achieved.
6.1.3 Curing Oven Emission Control Systems
In Table 6-1, the only control devices presently reported as in use
on curing oven emissions are direct flame afterburners and one fabric
filter. Test results are available for evaluation of several other
control devices used in the past for removal of particulates from curing
oven exhausts; these results are contained in Table 6-4. Each of the
systems would be able to comply with the typical SIP regulation for
particulates. No reports of test results for fabric filtration of curing
oven exhausts were obtained during this study. The resin binder in the
6-9
-------
Table 6-4. Controlled Particulate Emissions from Mineral Wool Curing Ovens
Number
of
Tests
1
1
Control
Equipment
ESP
Direct- flame
Dust Concentration
mg/scm (gr/scf)
Range Average
38.9 (0.017)
73.3 (0.032)
Emission Factor
kg/Mg (Ibs/ton)
Range Average
0.36 (0.72)
0.71 (1.42)
Reference
Present study
AP-40
afterburner
Wet scrubber
+ ESP
Catalytic
afterburner
To comply with
regulation
190 (0.083)
163 (0.071)
275 (0.12)
1.13 (2.26)
0.95 (1.90)
1.44 (2.87)
AP-40
AP-40
Typical SIP
-------
emitted curing oven participate might make fabric filters an impractical
control device by plugging the pores of the bags.
In AP-40, there is one test result for a catalytic afterburner and
one test result for a direct-flame afterburner for inlet and outlet
emissions of aldehydes. The direct-flame afterburner removed 57 percent
and the catalytic afterburner 53 percent of aldehydes from the curing
oven exhaust.
6.1.4 Cooler Emission Control Systems
The cooler is a relatively minor source of pollutants compared to
the other emission points in a mineral wool plant as indicated by the
emissions inventory for a typical plant in Table 5-9. There is a
direct-flame afterburner reported in use to control cooler emissions at
one plant. However, the usual practice apparently is not to control
emissions from the cooler. Since the cooler is a minor source, it
is not identified in most cases when plants report emission sources to
the States. No test data were obtained for the evaluation of any cooler
emission control devices.
6.1.5 Processing Changes to Reduce Emissions
6.1.5.1 Raw Material Composition - Sulfur compound emissions are
related to the sulfur content of the coke and slag charged to the
cupolas. The typical sulfur limit for coke is a maximum of 0.6 percent
based on discussion with personnel at several plants visited during the
source category survey. Another potential source of sulfur is that
contained in the slag charged to the cupola. At one plant visited, it
was the judgment of an official from the State control agency that sulfur
compound emissions were associated with sulfur content of the slag. The
6-11
-------
sulfur content of the slag was reported as 1.64 percent based on the
supplier's analysis, and an EPA analysis of the same slag was reported
to be higher. A consultant to the plant estimated that hydrogen sulfide
Concentrations in the cupola exhaust had been reduced from the 500 ppm
level to the 200 ppm level by changing slag suppliers thereby effecting a
reduction in the sulfur content of the slag. Sample results for sulfur
content of the slag after the change of suppliers were not available to
help confirm this association. This plant also had a problem with high
fines content of the slag which reportedly caused increased particulate
emissions. Photographs of the slag were shown with golf balls placed on
the slag pile for comparison purposes. The slag seemed to consist of a
much greater proportion of particles considerably smaller than the golf
balls that had been observed at other plants visited during the source
category survey.
6.1.5.2 Replacement of Cupolas with Electric Furnaces - An electric furnace
is reportedly in operation in Europe, and a Canadian plant is also reported
o
to be manufacturing mineral wool using an electric furnace. A United States
company plans to start mineral wool production using an electric furnace
g
in 1980. In addition to significantly lower emissions from an electric
furnace, there are potentials for fuel savings and decreased losses due
to shot production. A drawback to the use of electric furnaces is the highly
corrosive and erosive action of the slag on the refractory lining. In
addition to possible economic consideration, discussions with plant personnel
during the survey indicated some reluctance on the part of companies to
be the first in the United States industry to operate an electric furnace.
This observation is supported by the fact that two plants started up in 1978,
11 12
and both plants installed cupola melting furnaces. '
6-12
-------
6.2 ALTERNATIVE CONTROL SYSTEMS
The process steps that could be considered for further NSPS investigation
are the cupola, blowchamber, and curing oven emission points. The cooler
was not considered further due to the relatively low emission levels and
the general lack of control technology applications in the industry for
control of this emission point.
The alternatives for control of mineral wool plant emissions are
contained in Table 6-5. All three of the alternatives address particulate
control of the cupolas, blowchambers, and curing ovens. Only the first
alternative considers control of cupola carbon monoxide emissions and
curing oven VOC emissions.
6.3 IMPACT OF MINERAL WOOL MANUFACTURING ON AMBIENT AIR QUALITY
The impact that emissions from mineral wool manufacturing have on
the ambient environment was evaluated by estimating maximum ground level
concentrations using two simplified Gaussian dispersion models, PTDIS and
PTMAX. Particulate and carbon monoxide emissions from cupolas and
particulate emissions from blowchambers were included in this modelling
analysis. Two cupola configurations were considered for the particulate
concentration estimates; the first assumed a single cupola with exhaust
gases treated by a control device to comply with a typical SIP particulate
emission standard while the second case was considered to be a plant
utilizing a baghouse to control particulate emissions. When cupola
particulate emissions are controlled by fabric filtration, the gases
from two cupolas usually exhaust to the baghouse, typically composed of
several modules. For evaluating the impact of mineral wool process
carbon monoxide (CO) emissions on the ambient environment, the two
cupola configurations described above were considered to have no control
6-13
-------
Table 6-5
Alternative Control Systems
Control Technology*
Alternative Cupola Blowchamber Curing Oven
Alternative I FF + CO Control WS AB
System
Alternative II VS + ESP WS None
Alternative III FF FF None
* FF - fabric filter; VS - high energy venturi scrubber; WS - low energy
wet scrubber; AB - afterburner
6-14
-------
of CO emissions and also with a CO control system. The blowchamber was
assumed to be designed to accept the fiber output from one cupola with
an exhaust stack for each blowchamber at the plant.
Particulate emission rates complying with a SIP for the single cupola
case and the blowchamber are contained in Chapter 8 of this report. The
assumed values for gas temperature and flow rate are also contained in
Chapter 8. For cupola baghouse control, exhaust gas flow is double that
for the single cupola case, and the emission rate was considered to be equal
to the average of the tests for fabric filtration control of cupola
particulate emissions contained in Table 6-2. The stack heights for cupola
exhausts were assumed to be 15.24 meters (50 feet) for the single cupola
and the baghouse. The stack diameter for a single cupola was considered
to be 0.914 meter (3 feet) while a baghouse stack for controlling two
cupolas was assumed to be 1.22 meters (4 feet). The controlled CO emission
rate from a cupola equipped with a control system was assumed to be
5 percent of the uncontrolled emission rate (control system efficiency of
95 percent). The modelling inputs outlined above were selected as typical
based upon information collected during plant visits or obtained from State
agencies and NEDS.
The results from dispersion estimates for particulate and CO
concentrations around typical mineral wool plants are contained in
13
Table 6-6 and Table 6-7, respectively.
For particulate emissions from a cupola or a blowchamber complying
with the typical SIP, the maximum 24-hour average concentration would be
less than 3 percent of the national primary ambient air quality standard
in either case while the maximum annual average particulate concentration
would be less than 2 percent of the national primary ambient air quality
6-15
-------
Table 6-6. Maximum 24-Hour and Annual Ground Level Particulate
Concentrations Around Typical Mineral Wool Plants
(micrograms/cubic meter)
CTl
PI ant
Emi ssion
Source
Cupol al
Cupol a^
Bl owchamber
Di stance from
Plant (m)
600
750
600
24-Hour
SIP
Control
6.7
--
6.0
Average
Baghouse
Control
--
0.6
2.0
Annual
SIP
Control
1.3
--
1.2
Average
Bagho
Cont
--
0.1
0.4
use
rol
1 Plant controlled to meet SIP was assumed to have separate stack for
each cupola.
2 Plant controlled with baghouse was assumed to combine exhaust gases
from two cupolas.
-------
Table 6-7. Maximum 1-Hour and 8-Hour Ground Level Carbon Monoxide
Concentrations Around Typical Mineral Wool Plants
(micrograms/cubic meter)
1-Hour Average
8-Hour Average
Plant
Cupola^
Cupol a2
Distance from
Plant (m)
600
750
No
Control
1,770
1,890
CO Control
System
88
94
No
Control
890
940
CO Contr
System
44
47
1 Plant not controlled with baghouse assumed to have separate stack for
each cupola.
2 Plant controlled with baghouse assumed to combine exhaust gases from two
cupolas.
-------
standard for either emission point. Baghouse control of the cupolas or
a blowchamber would result in estimated maximum particulate concentrations
less than 1 percent of the 24-hour average and annual average national
primary ambient air quality standards. Although control of blowchamber
emissions with a baghouse was reported for one plant (see Table 6-1) and
therefore included in the modeling analysis, the lower blowchamber
exhaust gas temperature, as compared to the cupola exhaust gas tempera-
ture plus increased moisture content of the gas when steam is used for
fiber attenuation, might make blowchamber baghouse control impractical
as a result of condensation and possible attendant corrosion problems.
The maximum 1-hour average CO concentration estimates for a cupola
with a separate exhaust stack and for cupolas controlled with a baghouse
are both less than 5 percent of the national primary ambient air quality
standard for CO, and when controlled with a CO control system, both are
estimated to be reduced to less than 1 percent of the 1-hour average
standard. For an 8-hour averaging time, a cupola with a separate exhaust
stack and cupolas with baghouse particulate control are estimated to result
in maximum ambient CO concentrations less than 10 percent of the national
primary ambient air quality standard and the estimated concentrations are
reduced to less than 1 percent of the national primary ambient air quality
standard for cupolas with CO control systems.
6-18
-------
REFERENCES
1. Memorandum from R.E. Rosensteel, United States Environmental
Protection Agency, to J.U. Crowder, United States Environmental
Protection Agency, November 1979. Visit to Rockwool Industries Mineral
Wool Plant, Fontana, California.
2. Schneider, R.C. Report on Carbon Monoxide and Nitrogen Oxides
Emissions from the Cupola Furnace with Varying Underfire Conditions.
San Bernadino Air Pollution Control District. San Bernardino,
California. Engineering Evaluation Report 74-13. April 30, 1974.
6 pages.
3. Powlesland, W.H., C.H. Knight, and J.W. Smith. Dry Catalytic
Removal of Hydrogen Sulfide from Mineral Wool Cupola Flue Gas. The
Fourth International Clean Air Congress. Tokyo, Japan. 1977. Pages 756
through 758.
4. Reference 3, Page 757.
5. Nishimura, B., and R.J. Hilovsky. Report on Particulate Matter and
Sulfur Dioxide Emissions from a Cupola Furnace with a Baghouse Control.
San Bernardino Air Pollution Control District. San Bernardino,
California. Engineering Evaluation Report 72-37. January 10, 1973.
8 pages.
6. Personal communication. J. Winberry, North Carolina Department of
Natural Resources, with R. Rosensteel, United States Environmental
Protection Agency. June 25, 1979.
7. Memorandum from L. Anderson, United States Environmental Protection
Agency, to J.U. Crowder, United States Environmental Protection Agency.
October 2, 1979. Visit to Spring Hope Rockwool, Incorporated, Spring
Hope, North Carolina.
8. Personal communication. 0. Gould, Spring Hope Rockwool, Incorporated,
with R. Rosensteel, United States Environmental Protection Agency.
June 25, 1979.
9. Telecon. L. Anderson, United States Environmental Protection
Agency, with W. Millard, Virginia State Air Pollution Control Board.
November 1, 1979. Mineral wool plants operating in Virginia.
10. Cobble, J.R., and J.P. Hansen. Evaluation of Refractories for
Mineral Wool Furnaces. United States Bureau of Mines. Tuscaloosa,
Alabama. December 1975.
6-19
-------
11. Reference 7.
12. Telecon. L. Anderson, United States Environmental Protection
Agency, with E. Fulton, Texas Air Control Board. April 17, 1979.
Mineral wool plants operating in Texas.
13. Memorandum from G.J. Schewe, United States Environmental Protection
Agency, to R.E. Rosensteel, United States Environmental Protection
Agency. October 17, 1979. Dispersion Estimates for Emissions from
Mineral Wool Plants.
6-20
-------
7. EMISSION DATA
7.1 AVAILABILITY OF DATA
The emission data obtained from State and local control agencies
during the conduct of this study are identified in Table 7-1. In some
cases, where only data summaries have been obtained, more detailed data
might be available from the control agencies and/or companies.
7.2 SAMPLE COLLECTION AND ANALYSIS
Reference methods are defined in 40 CFR Part 60 Appendix A for
sample collection and analysis of air pollutants; specific EPA reference
methods that may be applied to the evaluation of emissions from mineral
wool processes include:
Method 1 - Sample and Velocity Traverses for Stationary Sources
Method 2 - Determination of Stack Gas Velocity and Volumetric Flow
Rate
Method 5 - Determination of Particulate Emissions from Stationary
Sources
Method 6 - Determination of Sulfur Dioxide Emissions from
Stationary Sources
Method 7 - Determination of Nitrogen Oxide Emissions from
Stationary Sources
Method 8 - Determination of Sulfuric Acid Mist and Sulfur Dioxide
Emissions from Stationary Sources
Method 9 - Visual Determination of the Opacity of Emissions from
Stationary Sources
7-1
-------
TABLE 7-1. AVAILABILITY OF EMISSION TEST RESULTS
ALABAMA - DEPARTMENT OF HEALTH, JEFFERSON COUNTY
Plant Name
and City
U. S. Gypsum
Birmingham, AL
U. S. Gypsum
Birmingham, AL
U. S. Gypsum
Birmingham, AL
f
U. S. Gypsum
Birmingham, AL
U. S. Gypsum
i Birmingham, AL
ro
Rockwool Industries
Leeds, AL
Rockwool Industries
Leeds, AL
Date
2/74
and
3/74
4/74'
8/74
3/76
11/77
11/78
11/78
Process
Source
Cupola
Cupola
Cupola
Blowchamber
Curing Oven
Cupola
Bl owchamber
Control
Equipment
Multiple
cyclones
Multiple
cyclones
Multiple
cyl cones
Spray
chamber
ESP
Baghouse
Wet Scrubber
CALIFORNIA - SOUTH COAST AIR QUALITY
Rockwool Industries
Fontana, CA
Rockwool Industries
Fontana, CA
Rockwool Industries
Fontana, CA
10/70
10/70
10/70
Cupola
Batt line
Blown wool
room
Wet Scrubber
Wet Scrubber
Met Cyclone
Sample
Point
Control
device
outlet
Control
device
outlet
Control
device
outlet
Control
device
outlet
Control
device
outlet
Control
device
outlet
Control
device
outlet
MANAGEMENT
Control
device
outlet
Control
device
outlet
Control
device
outl et
Pollutant(s)
Sampled
Particulates
Particulates
Particulates
Particulates
Particulates
Particulates
Particulates
DISTRICT, COLTON,
Particulates
NOX
cox
Particulates
NO,
CO
Particulates
NOX
Method
EPA-5
EPA-5
EPA-5
EPA-5
EPA-5
EPA-5
EPA-5
CALIFORNIA
Not specified
Not specified
Not specified
Not specified
Not specified
Not specified
Not specified
Not specified
Data
Received
Summary and
data sheets
Summary and
data sheets
Summary and
data sheets
Summary and
data sheets
Summary and
data sheets
Summary and
data sheets
Summary and
data sheets
Summary only
Summary only
Summary only
-------
CALIFORNIA - SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT, COLTON, CALIFORNIA (Continued)
Plant Name
and City Date
Rockwool
Fontana,
Rockwool
Fontana,
Rockwool
Fontana,
Rockwool
Fontana,
Rockwool
Fontana,
"J*1 Rockwool
co Fontana,
Rockwool
Fontana,
Rockwool
Fontana,
Rockwool
Fontana,
Rockwool
Fontana,
Industries 2/71
CA
Industries 11/72
CA
Industries 2/74
CA
Industries 4/74
CA
Industries 6/74
CA
Industries 4/76
CA
Industries 8/77
CA
Industries 12/77
CA
Industries 12/77
CA
Industries 6/79
CA
Process
Source
Cupola
Cupola
Cupola
Cupola
Cupol a
Cupol a
Cupola
Batt room
Blow room
Cupol a
Control
Equipment
Wet Scrubber
Pilot
Baghouse
Baghouse
Baghouse
Baghouse
Baghouse
Baghouse
None
None
Baghouse +
CO Control
System
Sample
Point
Control
device
outlet
Pollutant(s)
Sampled
Particle size
distribution
Fluorides
Control Parti culates
device S02
inlet
and outlet
Control
device
outlet
Control
device
outlet
Control
device
outlet
Control
device
outlet
Control
device
Inlet
Room
exhaust
Room
exhaust
Outlet
from
control
devices
Participates
S02
CO
CO
NOX
Participates
Particulates
SO?
NOX
CO
Particulates
S02
CO
NOX
Hydrocarbons
Particulates
Particulates
CO
Method
Andersen sampler
Not specified
Not specified
Electrochemical
cell continuous
measurement
Not specified
Not specified
Not specified
Gas chromatography
Phenol disulfonic
add
EPA-5 and
APCD
Unknown
APCD
APCD
Unknown
Not specified
Not specified
Not specified
Not specified
Not specified
Not specified
Not specified
Gas chromatography
Data
Received
Summary
Summary
Summary
Summary
Summary
Summary
Summary
Summary
Summary
Summary
only
only
only
only
only
only
only
only
only
only
-------
INDIANA - AIR POLLUTION CONTROL BOARD, STATE OF INDIANA
Plant Name
and City
Rockwool Industries
Alexandria, IN
Celotex Corporation
Lagro, IN
U. S. Gypsum
Wabash, IN
Johns-Manvil le
Alexandria, IN
Date
10/72
6/74
12/74
8/71
Process
Source
Cupola
Cupola
Cupola
Cupola
Control
Equipment
None
Multiple
cyclones
Multiple
cyclones
None
Sample
Point
Cupola
exhaust
Control
device
outlet
Control
device
outlet
Cupola
exhaust
Pollutant(s)
Sampled
Particulates
S02
NOX
Fluorides
Particulates
Particulates
Particulates
SO
Fluorides
Method
ASME-PTC27
Los Angeles
Phenoldisulfonic
acid
Los Angeles
Not specified
Not specified
ASME PTC-27
Los Angeles
Los Angeles
Dat.i
Received
Summary only
Summary only
Summary only
Summary and
data sheets
MISSOURI DEPARTMENT OF NATURAL RESOURCES, JEFFERSON CITY
Rockwool Industries 5/78 Cupola
Cameron, MO
Baghouse
Control
device
outlet
Particulates
Hot specified
Summary only
-------
8. STATE AND LOCAL EMISSION REGULATIONS
The following section summarizes the emission regulations concerning
newly constructed mineral wool manufacturing plants. Only the regula-
tions of the 14 States where mineral wool is currently manufactured were
examined. It is believed that these 14 States are representative of the
emission standards for all 50 States. These regulations were primarily
taken from the Environment Reporter with supplemental information
gathered from State and local air pollution control agencies.
Emission regulations are presented and compared in Table 8-1. In
order to compare the various State regulations, it was necessary to
choose process weight rates and exhaust gas flow rates for a typical
plant. A typical plant was assumed to have the following parameters:
Cupolas: charging rate - 3 T/hr
exhaust gas temperature - 300°F
exhaust gas flow rate - 6600 scfm (9650 acfm at 300°F)
Blowchambers: process weight rate - 1.8 T/hr
exhaust gas temperature - 180°F
exhaust gas flow rate - 20,000 scfm (24,800 acfm at 180°F)
Curing Ovens: process weight rate - 1.8 T/hr
exhaust gas temperature - 320°F
exhaust gas flow rate - 5000 scfm (7500 acfm at 320°F)
8-1
-------
Table 8-1. Summary of Participate Emission Regulations
for New Mineral Wool Manufacturing Processes
State
Al abama
California
Colorado
Illinois
Indiana
Minnesota
CO Missouri
ro
New Jersey
North Carolina
Ohio
Pennsylvania
Tennessee
Texas
Washington
Number
of
Plants
3
1
1
1
6
2
2
1
1
1
3
1
3
1
General
Process
Regulation3
Class I county:
E = 3.59 pO-62
Class II county:
E = 4.1 P0.67
b
E = 3.59 P0-62
E = 2.54 P0-534
E = 4.1 P0-67
E = 3.59 P0-62
E = 4.1 P°-67
99% removal of uncon-
trolled partlculates
(removal not required
below 0.02 gr/scf)
E = 4.1 P°'67
E = 4.1 P°'67
0.04 gr/scf
E = 3.59 P°-62
BEST AVAIL
0.1 gr/scf
Allowable Particulate Emissions
Cupola
Kg/h Ib/hr
3.22
3.89
3.22
2.08
3.89
3.22
3.89
0.51
3.89
3.89
1.03
3.22
A B L
2.57
7.09
8.56
b
7.09
4.57
8.56
7.09
8.56
1.13C
8.56
8.56
2.26
7.09
E CON
5.66
Blowchamber
Kg/h Ib/hr
2.35
2.76
2.35
1.58
2.76
2.35
2.76
1.56
2.76
2.76
3.12
2.35
T R 0 I
7.79
5.17
6.08
b
5.17
3.48
6.08
5.17
6.08
3.43C
6.08
6.08
6.86
5.17
TECH
17.14
Curing Oven
Kg/h Ib/hr P
2.35
2.76
2.35
1.58
2.76
2.35
2.76
0.39
2.76
2.76
0.78
2.35
N 0 L 0
1.95
5.17
6.08
b
5.17
3.48
6.08
5.17
6.08
0.86C
6.08
6.08
1.71
5.17
G Y
4.29
Visible
Emissions
ercent Opacity
20
b
20
30
40
20
20
20
20
20
20
20
20
20
E • allowable emissions (Ib/hr)
P = Process weight rate (tons/hr)
Q = Actual exhaust gas flow (acfm)
gr/scf - Allowable concentration of particulate matter In grains per standard cubic foot qf exhaust gas
Regulation Is by county or air pollution control district. For the South Coast district, no new plant can emit more
than 250 Ibs/day of any pollutant and opacity is limited to 20 percent.
c Based on 0.02 gr/scf
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In making this comparison, it was assumed that each State considers a
production line containing a cupola, blowchamber, and curing oven to
consist of three separate processes. It was also assumed that the
process weight rate was determined on a once-through basis (no increase
in allowable emissions could be achieved by returning the airlift exhaust
to the blowchamber so that the throughput could be counted twice in
determining the process weight rate).
In general, the only pollutant emitted from mineral wool processes
which is subject to regulation in every State is particulate matter.
The State of Pennsylvania requires the installation of afterburners on all
mineral wool curing ovens to control odors. Several States require
afterburners to control carbon monoxide emissions from grey iron foundry
cupolas, but mineral wool cupolas are not included in these regulations.
A typical mineral wool plant has two parallel production lines with
0 62
only one line having a curing oven. Taking E = 3.59p to represent
an average State general process emission regulation, this typical plant
could emit allowable particulate emissions totalling about 30 Ibs/hr from
the 5 emission sources operating at process rates previously stated.
Of those examined, the most stringent emission regulation was that
of the South Coast Air Quality Management District of California. Under
these regulations, no new mineral wool plant could be built which would
emit more than a sum of 250 Ibs/day of any pollutant from all emission
sources at the facility.
8-3
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REFERENCES
1. Environment Reporter. Bureau of National Affairs, Inc.
Washington, D. C.
8-4
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing
i. R
"^8/3-80-016
2.
4. TITLE AND SUBTITLE
Source Category Survey:
Mineral Wool Manufacturing Industry
3. RECIPIENT'S ACCESSION NO.
5 REPORT DATE , , nnr.
June 1980 March 1980
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Office of Air Quality Planning and Standards
Environmental Protection Agency
Research Triangle Park, North Carolina 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12.
SPONSORING AGENCY JMAME AND ADDRESS . . ,
DAA for Air Quality Planning and Standards
Office of Air, Noise and Radiation
U.S. Environmental Protection Agency
Research Triangle Park, N. C. 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA/200/04
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This report contains background information which was used for determining
the need for new source performance standards (NSPS) for the mineral wool
manufacturing industry in accordance with Section 111 of the Clean Air Act.
Air pollution emissions and growth trends of the mineral wool industry are
examined. Manufacturing processes, control strategies, and state and local
air pollution regulations are discussed. The impact of a potential NSPS
on particulate and carbon monoxide emissions is calculated.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Air Pollution
Pollution Control
Mineral Wool Manufacturing
Rock Wool Manufacturing
Slag Wool Manufacturing
New Source Performance Standards
Air Pollution Control
13 B
18. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (This Report)
21. NO. OF PAGES
20
Unclassified
. SECURIf Y CLASS'(This page)
Unclassified
22.PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
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