EPA-450/3-81 -003b
VOC Emissions
from Volatile Organic Liquid
Storage Tanks —
Background Information for
Promulgated Standards
Emission Standards and Engineering Division
U.S. Environmental Protection Agency
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park NC 27711
January 1987
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This report has been reviewed by the Emission Standards and Engineering Division of the Office of Air
Quality Planning and Standards, EPA, and approved for publication. Mention of trade names or commercial
products is not intended to constitute endorsement or recommendation for1 use. Copies of this report are
available through the Library Services Office (MD-35), U.S. Environmental Protection Agency, Research
Triangle Park NC 27711; or, for a fee, from the National Technical Information Services, 5285 Port Royal
Road, Springfield VA 22161.
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voc
ENVIRONMENTAL PROTECTION AGENCY
Background Information
and Final
Environmental Impact Statement for
Emissions from Volatile Organic Liquid Storage Tanks
J^fek^R. Farmer
director, Emission Standards and Engineering
U. S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
Division
1. The promulgated standards of performance would limit emissions of
volatile organic compounds (VOC) from new, modified, and reconstructed
VOL storage vessels. Section 111 of the Clean Air Act (42 U.S.C. 7441),
as amended, directs i;ha Administrator to establish standards of
performance for any category of new stationary source of air pollution
that". . . causes or contributes significantly to air pollution which
may reasonably be anticipated to endanger public health or welfare".
2. Copies of this document have been sent to the following Federal
Departments: Labor, Defense, Transportation, Commerce, Interior, and
Energy; the Council on Environmental Quality; members of the State and
Territorial Air Pollution Program Administrators; the Association of
Local Air Pollution Control Officials; EPA Regional Administrators; and
other interested parties.
3. For additional information contact:
Ms. Laura Butler or Mr. Doug Bell
Standards Development Branch (MD-13)
U. S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
Telephone: (919) 541-5267
4. Copies of this document may be obtained from:
U. S. EPA Library (MD-35)
Research Triangle Park, North
Telephone (919) 541-2777
Carolina 27711
National Technical Information Service
5285 Port Royal Road
Springfield, Virginia 22161
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TABLE OF CONTENTS
Section
1 SUMMARY [[[ 1-1
1.1 Summary of Changes Since Proposal .......................... 1-1
1.2 Summary of Impacts of the Promulgated Action ........... >... 1-3
1.2.1 Alternatives to Promulgated Action ........ . ........... 1-3
1.2.2 Environmental Impacts of Promulgated Action ........... 1-3
1.2.3 Energy and Economic Impacts of the
Promulgated Action ................................... 1-3
1.2.4 Other Considerations .................................. 1-4
1.2.4.1 Irreversible and Irretrievable Commitment
of Resources ................................... 1-4
1.2.4.2 Environmental and Energy Impacts of Delayed
Standards .......................... . ........... 1-4
1.2.4.3 Urban and Community Impacts ............ . ....... 1-4
2 SUMMARY OF PUBLIC COMMENTS .............. . ....................... 2-1
2.1 Selection of Affected Facility ................... .......... 2-1
2.1.1 Vapor Pressure and Tank Size Cutoff ................... 2-1
2.1.2 Vapor Pressure Determination .......................... 2-14
2.1.3 Special Exemptions .................................... 2-15
2.1.3.1 Horizontal and Underground Vessels ............. 2-15
2.1.3.2 Facilities Producing Beverage Alcohol .......... 2-23
2.1.3.3 Vessels Located on the Outer Continental
Shelf (OCS) ---- .' .................... .. .......... 2-23
2.1.3.4 "Slop Oil," Wastewater, and Waxy, Heavy
Crude Oil Storage Vessels ...................... 2-24
2.1.3.5 Negligibly Photochemical ly Reactive Liquids ____ 2-27
2.1.3.6 Production and Process Vessels ................. 2-28
2.1.3.7 Bulk Plant Storage Vessels. .................... 2-31
2.2 Emission Control Technology ................................ 2-32
2.2.1 External Floating Roof Vessels (EFR's) ................ 2-32
2.2.2 Internal Floating Roof Vessels (IFR's) ................ 2-33
2.2.3 Add-on Control Options ................................ 2-36
2.2.4 Column Fittings ....................................... 2-41
2.2.5 Alternative Means of Emission Limitation .............. 2-42
2.3 Recordkeeping, Reporting, and Inspection Requirements ...... 2-43
2.3.1 Recordkeeping and Reporting Requirements .............. 2-43
2.3.2 External Floating Roof Vessel (EFR) Inspection
Requirements. ......................................... 2-45
2.3.3 Internal Floating Roof Vessel (IFR) Inspection
Requirements .......................................... 2-46
2.3.3.1 Annual Visual Inspection ....................... 2-46
2.3.3.2 Ten-Year Inspection ............................ 2-48
2.3.4 Procedures for Vessels Found to be Out of Compliance.. 2-49
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TABLE OF CONTENTS
(continued) .
Section Page
2.4 Modification 2-51
2.5 Cost Effectiveness.... 2-52
2.5.1 Capital Recovery Factor 2-52
2.5.2 Product Recovery 2-52
2.5.3 Cost of Controls (Cost Effectiveness) 2-54
2.5.3.1 Add-On Controls 2-54
2.5.3.2 Floating Roof Vessels j... 2-55
2.6 Mi seel 1 aneous 2-58
2.7 References for Chapter 2 2-62
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LIST OF TABLES
Table Page.
2-1 List of Commenters on Proposed Standards of Performance
for Volatile Organic Liquid Storage Vessels 2-2
2-2 Cost Effectiveness of BDT Controls for a 113-m3 Tank 2-11
2-3 Cost Effectiveness of a 95 Percent Efficient
Condenser for Chloroform Storage at Chloroform Production
F ac i 1 i t i e s 2-19
2-4 Cost Effectiveness of a 95 Percent (Mass) Efficient
Condenser 2-20
2-5 Cost Effectiveness of a 95 Percent (Mass) Efficient
Condenser 2-21
2-6 Cost Effectiveness of a 95 Percent (Mass) Efficient
Condenser 2-22
2-7 Cost Effectiveness of BOT for Constant Level Tanks 2-30
2-8 Estimated Installed Cost of a Welded Contact Internal
. Floating Roof With Secondary Seal 2-57
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1. SUMMARY
On July 23, 1984, the Environmental Protection Agency (EPA) proposed
standards of performance for volatile organic liquid (VOL) storage vessels
(including petroleum liquid storage vessels) (49 FR 29698) under authority
of Section 111 of the Clean Air Act. Public comments were requested in the
proposal in the Federal Register. A total of 15 comments from industry,
6 from trade associations, and 3 from governmental agencies were submitted
during the comment period. The comments that were submitted, along with
responses to these comments, are summarized in this document. The summary
of comments and responses serves as the basis for the revisions made to the
standards between proposal and promulgation. . •
1.1 SUMMARY OF CHANGES SINCE PROPOSAL
In response to public comments, certain changes have been made in the
proposed standards. The more significant changes are summarized below.
All changes that have been made to the regulation are explained fully in
the responses to comments.
The Agency has reevaluated the vapor pressure cutoff. For storage
vessels with a capacity greater than or equal to 151 m (s40,000 gal), the
vapor pressure cutoff has been revised from "greater than or equal to
3.5 kPa (sO.51 psia)" to "greater than or equal to 5.2 kPa (sO.75 psia)."
Three specific exemptions to the standards were made in response to
requests from commenters. An exemption was added for storage vessels at
retail gasoline service stations. The EPA did not intend to affect
vessels at gasoline service stations with these standards. Consequently,
no evaluation of the possible economic impact of these standards on
retail gasoline marketers was performed. An exemption was also made for
bulk gasoline plants. These plants have been identified as small
businesses, and there is a potential for the impact of the standards to
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result in an adverse economic impact on bulk plants. Storage vessels at
gasoline service stations and bulk plants are part of a separate source
category, and the decision as to whether to regulate emissions from
these vessels is being made in a regulatory decision package for:that
category. Refer to Section 2.1.3.1, Horizontal and Underground Vessels,
and Section 2.1.3.7, Bulk Plant Storage Vessels, for further explanation of
the changes.
Facilities producing beverage alcohol have been excluded from the
standards because they have been previously exempted from the priority list
as part of a source category. Refer to Section 2.1.3.2, Facilities
Producing Beverage Alcohol, for further discussion of the change.
Two changes were made to the control technology requirement. The
major change is that the best demonstrated technology (BOT) for column
fittings has been expanded to allow the use of gasketed sliding covers in
addition to flexible fabric sleeve seals. The Agency determined that the
requirement for flexible fabric sleeve seals in the proposed standards was
unduely restrictive because these seals are not presently available on
noncontact decks. Refer to Section 2.2.4, Column Fittings, for further
discussion of the change. ',
The other change to the control technology requirements is a revision
to the flare exit velocity limitations. A recently completed EPA test
program has shown that flares can efficiently remove volatile organic
compounds (VOC's) at higher exit velocities when the net heating value of
the gas being combusted is high. Refer to Section 2.2.3, Add-on ^Control
Options, for further explanation of the change.
Two major changes were made to the monitoring requirements. Vessels
classified as "waste" tanks are subject to revised vapor pressure
monitoring requirements based on semiannual physical testing rather than
frequent (perhaps daily) determinations to estimate the vapor pressure of a
waste mixture of indeterminate or variable composition. Refer to
Section 2.1.3.4, "Slop Oil," Wastewater, and Waxy, Heavy Crude Storage
Vessels, for further explanation of the change.
The other major change has been made to the annual inspection
requirement for internal floating roof seal systems. The Agency has
determined that it may not be possible to inspect these vessels without
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emptying and degassing the vessel. The inspection requirement has been
revised to allow the owner or operator the option to equip the vessel
with a primary and a secondary seal and conduct an internal inspection
every 5 years. This option is considered equivalent to an annual visual
inspection of a single-seal system. Refer to Section 2.3.3.1, Annual
Visual Inspection, for further discussion.
1.2 SUMMARY OF IMPACTS OF PROMULGATED ACTION
1.2.1 Alternatives to Promulgated Action
The regulatory alternatives are discussed in Chapter 6 of the Volume I
background information document (BID) for the proposed standards
(EPA-450/3-81-003a). These regulatory alternatives reflect the different
levels of emission control from which one that represents BDT is selected,
considering costs, nonair quality health, and environmental and economic
impacts for VOL storage vessels. Regulatory Alternative III has been
revised to expand the options for fitting controls. As discussed in
Section 1.1, the owner or operator has the option of installing gasketed
sliding covers instead of flexible fabric sleeve seals.
1.2.2 Environmental Impacts of Promulgated Action
The environmental impacts are discussed in Chapter 7 and Appendix D of
the Volume I BID. Data are not available to determine with precision the
effects of changing the vapor pressure cutoff from 3.5 to 5.2 kPa (0.51 to
0.75 psia), but any effects would be relatively small or negligible.
Therefore, the Volume I BID now becomes the final Environmental Impact
Statement for the promulgated standards.
1.2.3 Energy and Economic Impacts of the Promulgated Action
The energy impacts of the proposed standards are evaluated in
Chapter 7 of the Volume I BID. It was determined that the control
technologies that are the bases for the regulatory alternatives do not
increase the power or other energy requirements of VOL storage vessels.
Therefore, no energy impacts are attributed to-the proposed or final
standards.
The economic impacts of the proposed standards are evaluated in
Chapter 9 of the Volume I BID. Since proposal, the cost of the liquid-
mounted primary seal has been revised upward to $98.40/meter ($30.00/foot)
and the expected lifetime of the seals revised downward to 10 years
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(refer to Section 2.5.3.2, Floating Roof Vessels). The cost of fitting
controls has also been revised (refer to Section 2.2.4, Column Fittings,
and Section 2.5.3.2, Floating Roof Vessels). These changes have been
incorporated into the analysis of the fifth year economic impact of the
standards. The fifth-year impact still yields a net credit.
1.2.4 Other Considerations
1.2.4.1 Irreversible and Irretrievable Commitment of Resources. The
Volume I BID concluded in Chapter 7 that no long-term environmental losses
would result from the regulatory alternatives. The regulatory alternatives
do not preclude the development of future control options that would be
beneficial to the environment. The analysis of the final standards remains
unchanged in this respect.
1.2.4.2 Environmental and Energy Impacts of Delayed Standards. As
discussed in Chapter 7 of the Volume I BID, the only environmental impact
associated with a delay in proposing and promulgating the standards would
be an increase in VOC emissions from storage tanks attributable to the
construction of new tanks. ;
1.2.4.3 Urban and Community Impacts. There are no- urban and
community impacts attributable to the proposed or promulgated standards.
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2. SUMMARY OF PUBLIC COMMENTS
A list of commenters, their affiliations, and the EPA docket entry
number assigned to each comment are shown in Table 2-1. Twenty-four
letters containing comments on the proposed standards for VOL storage
vessels and the BID for the proposed standards were received. Significant
comments have been organized into the following six categories:
1. Selection of Affected Facility;
2. Emission Control Technology;
3. Recordkeeping, Reporting, and Inspection Requirements;
4. Modification;
5. Cost Effectiveness; and
6. Miscellaneous.
The comments and the issues they address are discussed in the following
sections of this chapter.
2.1 SELECTION OF AFFECTED FACILITY
2.1.1 Vapor Pressure and Tank Size Cutoff
Comment: Several commenters questioned the 3.5 kPa (sO.51 psia)
vapor pressure cutoff for tanks with capacities greater than 151 m3
(a40,000 gal). Two commenters (IV-D-18, IV-D-21) said that the proposed
regulation should be consistent with the existing Subparts K and Ka and
limit application of controls to vessels over 151 m3 (s40,000 gal) in
capacity that store liquids with true vapor pressures above 10.4 kPa
(si.5 psia). One commenter (IV-D-15) suggested-that the 10.4 kPa (1.5
psia) cutoff be maintained to achieve consistency with State
implementation plans (SIP's).
Response: Section 111 of the Clean Air Act requires EPA to establish
standards that reflect best demonstrated technology (BDT). The EPA has
identified BDT for tanks storing liquids in the vapor pressure range of
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TABLE 2-1. LIST OF COMMENTERS ON PROPOSED STANDARDS OF
PERFORMANCE FOR VOLATILE ORGANIC LIQUID STORAGE VESSELS
Docket item No.a Commenter/affillation
IV-D-1 Mr. Richard E. Grusnick
Air Division
Alabama Department of Environmental
Management
1751 Federal Drive
Montgomery, Ala. 36109
IV-D-2 Mr. D. E. Park
Director, Corporate Environmental Affairs
Ethyl Corporation
P.O. Box 341
Baton Rouge, La. 70821
IV-D-3 Mr. Bruce Blanchard
Director, Environmental Project Review
U.S. Department of the Interior
Office of the Secretary
Washington, D.C. 20240 .
IV-D-4 Mr. Fin Johnson
North Carolina Department of Natural
Resources and Community Development
P.O. Box 27687
Raleigh, N.C. 27611
IV-D-5 Mr. Robert F. Brothers
Director, Regulatory Affairs
Eastman Kodak Company
343 State Street
Rochester, N.Y. 14650
IV-D-6 Mr. Peter W. McCallum
Senior Corporate Environmental Scientist
The Standard Oil Company (Ohio)
Midland Building
Cleveland, Ohio 44115
IV-D-7 Mr. J. K. Walters
Director, Measurement Coordination
American Petroleum Institute
1220 L Street, N.W.
Washington, D.C. 20005
(continued)
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TABLE 2-1. (continued)
Docket item No.a
Commenter/affi1iation
IV-D-8
IV-D-9
IV-0-10
IV-D-11
IV-D-12
IV-0-13
IV-D-14
Mr. W. T. Danker
Manager, Environmental Programs
Environment, Safety, Fire and Health
Chevron U.S.A. Inc.
P.O. Box 7643
San Francisco, Calif. 94120
Mr. A. H. Nickolaus
Chairman, CTG Subcommittee
Air Conservation Committee
Texas Chemical Council
1000 Brazos, Suite 200
Austin, Tex. 78701
Mr. M. E. Miller, Jr.
Manager, Environmental Engineering Unit
R. J. Reynolds Tobacco Company
Winston-Salem, N.C. 27102
Mr. John J. Moon
Manager, Environment and Consumer Protection
Phillips Petroleum-Company
Bartlesville, 0-kla. 74004
Dr. Geraldine V. Cox
Vice President
Technical Director
Chemical Manufacturers Association
2501 M Street, .N.W.
Washington, D.C. 20037
Mr. Ronald F. Black
Environmental Specialist
Rohm and Haas Company
Engineering Division
P.O. Box 584
Bristol, Pa. 19007
Mr. Lawrence B. Gotlieb
Assistant General Counsel
Distilled Spirits Council of the United
States, Inc.
1250 Eye Street, N.W., Suite 900
Washington, D.C. 20005
(continued)
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TABLE 2-1. (continued)
Docket item No.a
Commenter/affiliation
IV-D-15
IV-D-16
IV-D-17
IV-D-18
IV-D-19
IV-D-20
Mr. Tom E. Lingafeller
Manager, Environmental Regulatory Activities
for Air
Dow Chemical U.S.A.
2030 Willard H. Dow Center
Midland, Mich. 48640
Mr. Phillip L. Youngblood
Director, Air Programs
Conoco Inc.
Suite 2136
P.O. Box 2197 ;
Houston, Tex. 77252
Mr. Walter Roy Quanstrom
General Manager
Environmental Affairs and Safety
Department
Standard Oil Company (Indiana)
200 East Randolf Drive
Chicago, 111. 60601
Mr. John Prokop
President and General Counsel •
Independent Liquid Terminals Association
1133 15th Street, N.W.
Suite 204 '.
Washington, D.C. 20005
Mr. Kirk F. Sniff
Manager, Environmental Section
Legal Department
The Southland Corp.
P.O. Box 719
Dallas, Tex. 75221
Mr. Joseph J. Zlogar
Environmental Engineer
Northern Petrochemical Company
P.O. Box 459
Morris, 111. 60450
(continued)
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TABLE 2-1. (continued)
Docket item No.a
Commenter/affiliation
IV-D-21
IV-D-22
IV-D-23
IV-D-39
Mr. L. G. Lund
Manager of Regulatory Affairs
Health, Environment and Safety
Himont U.S.A., Inc.
P.O. Box 1687
Lake Charles, La. 70602
Mr. L. K. Arehart
Supervisor, Regulatory Analysis
Health and Environmental Affairs Department
Diamond Shamrock Corp.
717 North Harwood Street
Dallas, Tex. 75201
Mr. Alan T. Roy
Allied Corp.
Fibers Division
Margaret and Bermuda Streets
Philadelphia, Pa. 19137
Mr. Walter G. Wright, Jr.
Assistant Counsel
Petroleum Marketers Association of America
•1120 Vermont Avenue,. N.W.. ' •
Suite 1130
Washington, O.C. 20005
aThe docket No. for this project is A-80-51. Dockets are on file at
EPA Headquarters in Washington, D.C. and at the Office of Air Quality
Planning and Standards in Durham, N.C.
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5.2 to 10.4 kPa (0.75 to 1.5 psia) and is, therefore, promulgating
standards reflecting BDT. (Refer to the next response for an explanation
of changes made to the vapor pressure cutoff.) Consistency with some
SIP's or with the existing standards (Subparts K and Ka) is not germane.
Comment; Two commenters (IV-D-15, IV-D-18) stated that no data are
presented that show a significant reduction in emissions from vessels
storing liquids between 3.5 and 10.4 kPa (0.51 and 1.5 psia). One com-
menter (IV-D-15) said that no evidence is presented showing that emissions
from these vessels contribute to ozone formation. Another commenter
(IV-D-21) maintained that control of vessels storing liquids having vapor
pressures between 3.5 and 10.4 kPa (0.51 and 1.5 psia) would not con-
tribute greatly to the reduction in emissions, and these vessels are less
cost effective to control than vessels storing liquids with vapor
pressures above 10.4 kPa. One commenter (IV-D-18) said that the emission
reduction attributed to vessels of this size class is overstated at "for-
hire" terminals because of the low turnover rate (approximately five per
year) on these vessels. He suggested that the number of turnovers be
added as a cutoff criterion. This commenter also suggested that floating
roof vessels average at least 10 annual turnovers.and fixed roof vessels.
average at least 50 annual turnovers before becoming subject to the
control requirement.
Response; These comments address three issues related to the
selection of affected facilities; (1) the cost effectiveness of
controlling emissions from vessels storing VOL's with vapor pressures
between 3.5 and 10.4 kPa (0.51 and 1.5 psia), (2) the use of annual
turnovers as an exemption or cutoff criterion; and (3) the contribution of
the standards at the proposed level to emission reduction.
The Agency reevaluated the cost effectiveness of controlling
emissions from vessels storing VOL's in this vapor pressure range^. The
Agency recognizes that there will be variations in cost-effectiveness
values within a class. In particular, certain subclasses of vessels (for
example, vessels storing low vapor pressure liquids) may have unreasonable
cost-effectiveness values, particularly when combined with other storage
parameters such as low annual turnovers. Therefore, the Agency has
limited the scope of the standards to preclude some of those vessels
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storing low vapor pressure chemicals, which may have unreasonable cost-
effectiveness values. This has been done by changing the vapor pressure
cutoff from 3.5 to 5.2 KPa (0.51 to 0.75 psia). While the exact number of
vessels excluded by the revision of the vapor pressure cutoff is not
known, the change in emission reduction is small.
It should be noted that cost effectiveness is not a measure of the
economic impact of the standards on individual owners. Rather, it is a
measure of the overall cost efficiency for various classes of sources
subject to the standard. Because it is practical to do so without
affecting the objectivity and enforceability of the standards, the Agency
has limited the scope of the standards to preclude some of the vessels
that have unreasonable cost-effectiveness values. Nevertheless, variation
in cost-effectiveness values among individual facilities does remain;
however, this is expected and is not unreasonable.
Furthermore, these cost-effectiveness estimates do not reflect the
indirect environmental benefits of these standards. Emissions from
storage of some potentially toxic chemicals will be controlled under these
standards. It was not possible to quantify these benefits in this case;
nonetheless, the existence of, these benefits, in light of the difficulty
of making additional distinctions among classes of tanks, was a factor in
the Agency's determination that the cost effectiveness of the standards is
reasonable.
The Agency also considered an exemption based on turnovers. The
Agency evaluated the cost effectiveness of BDT controls for a typical
chemical industry tank (a volume of 606 m3 [160,000 gal], diameter and
height of 9.2 m [30 ft]). Tanks of this volume associated with the
chemical industry typically turn over 60 times per year. However, in this
case, the analysis was conducted assuming 10 turnovers per year to
evaluate the cost effectiveness of controls at a low turnover rate. A
molecular weight of 80, a vapor pressure of 6.9 kPa (1.0 psia), and a
product value of $360/Mg were also assumed. The cost effectiveness of BDT
is about $l,140/Mg for this case.1
The commenter (IV-D-18) correctly noted that the Agency's analysis of
tanks in this size range was based on a turnover rate of 50. Because the
number of turnovers does play a role in the cost effectiveness of BDT
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controls for fixed roof tanks, the Agency examined the impact of low
turnover rates on the cost effectiveness of BDT controls in this vapor
pressure range (3.5 to 10.4 kPa [0.51 to 1.5 psia]). As the number of
'turnovers decreases, fixed roof tank emissions will decrease, the emission
reduction obtained by BDT will decrease, and, therefore, BDT will become
less cost effective.
The average volume of a tank at a "for-hire" terminal is about
3,300 m (871,000 gal). The analysis assumed a diameter of about 18.4 m
(60 ft), a height of about 12.2 m (40 ft), a mid-range vapor pressure
(6.9 kPa or 1.0 psia), a molecular weight of 80, and a product value of
$360/Mg. Built as a fixed roof tank, this vessel would emit 7.2 and
5.3 Mg/yr (7.9 and 5.8 tons/yr) at 5 and 2.5 turnovers per year,
respectively. The emission reductions obtained by constructing a BDT
internal floating roof tank in place of a fixed roof tank are about 6.7
and 4.8 Mg/yr (7.4 and 5.3 tons/yr) at 5 and 2.5 turnovers, respectively;
and the associated cost-effectiveness values are $520/Mg and $870/Mg at 5
and 2.5 turnovers, respectively.1
An exemption based on annual turnovers is not possible without
affecting the objectivity and enforceability of the standards. The number
of turnovers that any vessel storing VOL's undergoes is not constant from
year to year and cannot be predicted with certainty at the time a vessel
is built or reconstructed. Thus, standards designed to exempt individual
vessels that may have low turnover rates would be impractical both from an
enforcement perspective and from the owner's perspective.
The Agency has concluded that, even in cases of low turnover rates,
the control of vessels storing liquids with vapor pressure between 5.2 and
10.4 kPa (0.75 and 1.5 psia) is reasonable. As discussed above, a cutoff
based on turnovers is not practical even for those instances where cost-
effectiveness values are high. Therefore, because the overall cost of the
standards produces a net credit and because an exemption for the subclass
of low-turnover vessels is not practical, no changes based on turnovers
have been made to the proposed cutoffs in these final standards. However,
the final standards will reflect the change in vapor pressure cutoff.
The emission reduction achieved between 3.5 and 10.4 kPa (0.75 and
1.5 psia) cannot be quantified. However, the cost effectiveness of
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typical tanks in this vapor pressure range is reasonable. Also, the
overall emission reduction of the standards is 31,000 Mg (34,000 tons) and
results in a net annual credit. Therefore, this cutoff is reasonable.
Comment: One commenter (IV-D-12) requested that EPA reevaluate the
inclusion of small-volume (75- to 151-m3 [20,000- to 40,000-gal]) vessels
by using a range of annual turnovers. According to the commenter, low
turnover rates (less than 10 per year) for these vessels are not cost
effective. Another commenter (IV-D-18) said that the turnover rate for
75- to 151-m3 (20,000- to 40,000-gal) vessels in the for-hire terminal
industry is as low as 2.5 to 4 times per year. This commenter said that
EPA's selection of higher turnover rates results in overstated emission
reduction and understated cost-effectiveness values. A third commenter
(IV-D-9) requested that justification and data be given to support EPA's
selection of the turnover rate (50 per year) used in determining size
cutoffs.
Response: Data on turnovers are not available for tanks at terminals
(5.9 percent of the tank population) or petroleum refineries -(approximately
56 percent of the tank population). These data are available for chemical
industry tanks (38 percent of the tank population) in the 75- to 151-m3
(20,000- to 40,000-gal) size range. For example, a 75-m3 (20,000-gal)
tank in the chemical industry averages 260 turnovers per year. Assuming
as a worst case that the remaining 62 percent of the tanks only have four
turnovers per year, the average number of turnovers for a 75-m3
(20,000-gal) tank would be about 100. Therefore, 50 turnovers per year is
a conservative analytical basis for determining the cutoff.
While data on turnovers are not available for tanks located at
terminals, the Agency was able to examine the possibility of significant
numbers of small volume, low turnover vessels being located at
terminals. While some petroleum products such as gasoline meet the small
volume vapor pressure cutoff (27.6 kPa [4 psia]), these products are
typically stored in much larger tanks. According to an organic chemical
manufacturing data base, only 0.3 percent of the total storage volume of
organic chemicals is shipped and available, thereby, for storage at
for-hire terminals. Of this, less than 13 percent of the volume shipped
consists of liquids in the higher vapor pressure range (27.6 to 76.6 kPa
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(4 to 11.1 psia]) that would be affected under the standards in the 75- to
151-m3 (20,000- to 40,000-gal) size range.2 Therefore, the Agency
considers it unlikely that a significant number of storage vessels at
terminals in this size range would be affected by the standards. Despite
this, the Agency examined the cost effectiveness of BDT controls in a
113-m (30,000-gallon) tank for four specific liquids stored at terminals
and at two turnover rates (5 and 10 per year). Typical vessels located at
terminals turn over five times per year according to one industry
source. The results of these analyses are presented in Table 2-2. The
cost effectiveness at five turnovers annually ranged from $920/Mg to
$2,570/Mg and averaged $l,500/Mg. The cost effectiveness at 10 turnovers
annually ranged from a savings of $160/Mg to a cost of $890/Mg and
averaged $310/Mg. While BDT for these low turnover vessels results in
higher cost-effectiveness values than those for vessels with higher
turnovers, these costs are reasonable considering the difficulty of
discriminating between tanks with different turnover rates. As noted
previously, larger vessels, which are more common in the for-hire terminal
industry, are even more cost effective to control.
• The actual cost effectiveness of BDT controls is dependent upon
tank-specific parameters (diameter, height, and volume) and product-
specific parameters (vapor pressure, molecular weight, and chemical
formulation) that cannot be predicted and may be higher or lower than
those presented in Table 2-2. Because of these variable parameters, an
objective exemption that would exempt only those vessels that always have
low turnovers would be complex and impractical. Therefore, because the
average cost effectiveness is reasonable even at lower turnovers, no
changes in the volume cutoffs have been made in the final rule. ;
Comment; One commenter (IV-D-12) suggested that a range of diurnal
temperatures and product molecular weights be used in determining the
cutoff for vessels less than 151 m (40,000 gal) in capacity. Commenters
(IV-D-9, IV-D-12) said that the choice of an 11.1°C (20°F) diurnal temp-
erature change does not represent the norm and advised that an 8.3°C
(15°F) change would be more realistic. Two commenters (IV-D-12, IV-D-18)
noted that the use of a single molecular weight results in
overly-generalized analysis.
2-10
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TABLE 2-2. COST EFFECTIVENESS OF BDT CONTROLS FOR A 113-m3 TANK1
(Fourth-quarter 1984 dollars)
Compound
Cost effectiveness at
5 turnovers/yr,
$/Mg
Cost effectiveness at
10 turnovers/yr,
$/Mg
n-Pentane
Cyclopentane
.Isoprene
Ethyl"Ether
Average
1,600
2,570
1,350
920
1,500 .
460
890
300
(160)
310
2-11
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Response: Storage facilities located in coastal areas generally
experience lower average diurnal temperature changes than vessels located
further inland. However, an 11.1°C (20°F) change represents the national
norm. The average diurnal temperature change for the States of
California, Texas, Louisiana, and New Jersey was calculated to be 10.3°C
(18.5°F), which indicates that even in coastal States with a high propor-
tion of the nationwide storage population, the average diurnal temperature
change is greater than that suggested by the commenters.
The cost effectiveness of a 75-m3 (20,000-gal) tank storing a typical
VOL was examined for sensitivity to use of a 8.3°C (15°F) diurnal
temperature change. The selection of this diurnal temperature change
value affects the magnitude of breathing losses on the order of
13 percent. Breathing losses are typically small (approximately
10 percent in this case), and the impact of changing the temperature
factor on the cost effectiveness of control is small. The cost
effectiveness of storing a typical VOL was $311/Mg when an 11.1°C diurnal
temperature change was assumed, and was $325/Mg when an 8.3°C temperature
change was assumed. Because emission rates are not affected to an
excessive extent by differing diurnal.temperature changes and considering '
the impracticability of basing a national standard on differing local
temperature conditions, no change has been made in the final standards.
The Agency has adequately considered a range of molecular weights in
developing the standards. The responses to other comments on the proposed
standards utilize analyses based on a variety of product molecular
weights. The average cost effectiveness of controls is reasonable under a
wide range of storage situations, including varying molecular weights and
product prices.
Comment: Three commenters (IV-D-7, IV-D-8, IV-D-12) noted that the
American Petroleum Institute (API) is revising Bulletin No. 2518 that
provides the basis for estimates of evaporation loss from fixed roof
tanks. Two commenters (IV-D-7, IV-D-8) also noted that API is conducting
a test program to evaluate evaporation loss from fittings in external
floating roof tanks. According to one commenter (IV-D-7), the new
estimates of emissions from fixed roof vessels could alter the baseline
emission level. The other commenter (IV-D-12) noted that the new fixed
2-12
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roof emission estimates will include the effects of losses from tanks with
pressure vacuum vents. Because the existing estimates do not include this
variable, the commenter recommended that EPA delay making a determination
on small size cutoffs until the revised estimates are available. Another
commenter (IV-D-8) requested that EPA await the results of both emission
estimate revisions before finalizing the proposed standards because of
possible changes in the baseline emission level.
Response; The Agency considered the benefits of delaying
promulgation of the proposed standards until the results from the API test
program are available. A delay would allow the development of external
floating roof fitting loss equations, which would quantify more precisely
the emission reduction achievable with the use of BDT. However, if it is
assumed that the emission reduction achieved by controlling emissions from
external floating roof fittings would be comparable to the reduction
achieved with internal floating roof fittings, this reduction would be
very small in comparison to the overall emission reduction achieved by the
•standard. 'Therefore, the benefits of proceeding with final standards for
external floating roof tanks outweigh the benefits of delaying the
standards.
The fixed roof test program has the potential to modify the breathing
loss equations and to quantify the emission reduction obtained by using
vents. However, breathing losses are generally small (approximately
15 percent in the typical storage vessel that is 606 m3 [160,000 gal]),
and a reduction in breathing losses would not make a significant
difference in the cost effectiveness of internal floating roofs as a
control device.
The Agency also considered the fact that research test programs of
this nature have uncertain completion dates and that there is no guarantee
that the. program will be completed in a timely manner. A proposal without
subsequent, timely promulgation leaves the industry in an uncertain
position with respect to how affected facilities should achieve
compliance. The uncertainty also has a negative impact with respect to
State air programs and the issuance of permits.
Therefore, for the reasons noted above, the Agency has determined
that there are no benefits to be obtained from delaying the standards and
2-13
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has decided to proceed. It should be noted, however, that data from a
completed test program will be incorporated into the next review of these
standards and into the next revision of the EPA Publication AP-42.
2.1.2 Vapor Pressure Determination
Comment: Two commenters (IV-D-5, IV-D-9) suggested that EPA use the
annual average temperature instead of the maximum monthly average temp-
erature to determine maximum true vapor pressure. The commenters said
that this would be consistent with EPA's procedure for analyzing emissions
and cost effectiveness. A third commenter (IV-D-18) requested clari-
fication regarding which temperature should be used. The commenter also
questioned the fairness of requiring controls on vessels containing
liquids that may exceed the vapor pressure threshold only one day per year
or less.
Response: The EPA agrees that affected liquids may have vapor
pressures that are below the cutoffs for much of the year but also notes
that nonaffected liquids may have true vapor pressures above the cutoffs
for portions of the year such as daylight hours during summer months. In
developing the applicability provision, EPA realized that basing applic-
ability on maximum instantaneous'vapor pressure would result in the
broadest applicability and, therefore, the largest emission reduction.
This approach could cause planning problems for the industry because
owners and operators might not be able to adequately predict which vessels
would be affected. Because industry may not be able to account for
particularly hot days adequately, the instantaneous vapor pressure was
rejected as the basis of applicability.
The next applicability format examined was an annual average vapor
pressure. This format has the advantage that it is in line with the
emission calculation methodologies used in the BID. However, vapor
pressures of VOL's are higher in the warmer, summer months, when iambient
ozone levels are highest. If applicability were based on the annual
average vapor pressure, vessels would not come under the standards even
though they were storing liquids with true vapor pressures greater than
5.2 kPa (0.75 psia). These vessels would then emit significant quantities
of VOC's during the summer when ambient ozone levels are highest.
Therefore, EPA decided to examine a shorter time frame that would broaden
the applicability of the standards, particularly during the summer.
2-14
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An applicability based on maximum monthly average vapor pressure was
selected because this would have a broader applicability than annual
averages without the planning problems associated with an applicability
based on instantaneous vapor pressure and would base applicability on the
contribution to VOC emissions when ozone levels are highest. The unit
time basis of vapor pressure determination in the promulgated standards
remains unchanged from that in the proposed standards.
2.1.3 Special Exemptions
2.1.3.1 Horizontal and Underground Vessels. The fact that
horizontal and underground storage vessels were not specifically excluded
from the proposed standards prompted several comments.
Comment: Three commenters (IV-0-1, IV-0-16, IV-D-39) requested that
underground storage vessels at gasoline service stations be exempted from
the rulemaking. One commenter (IV-D-1) stated that it would be an
unnecessary recordkeeping burden for both the operators of smaller affected
vessels not subject to the control requirements and the regulatory agencies
that would have to keep the records. Two commenters (IV-D-1, IV-D-16)
stated, their belief that it wa-s not EPA's intent to include underground
storage vessels at gasoline service stations as affected facilities.
Response: Commenters are correct in their assertion that EPA did not
intend to affect vessels at gasoline service stations with these stan-
dards. Consequently, no evaluation of the possible economic impact of
these standards on gasoline marketers was performed. Emissions from
retail gasoline marketers are part of the gasoline marketing source
category (Petroleum Transportation and Marketing, 40 CFR § 60.16, Category
No. 23), as well as part of the VOL storage category. The decision as to .
whether to regulate emissions from these vessels is being made in a
regulatory decision package for that category. The Agency has decided to
specifically exempt storage vessels at gasoline service stations from the
final standards.
Comment: Commenters (IV-D-7, IV-D-16, IV-D-39) suggested that
underground storage vessels be excluded when the volume of liquid added to
and taken from the tank in a year does not exceed twice the volume of the
vessel. A provision of this nature is included in Subparts K and Ka, and
the commenters requested that it also be included in Subpart Kb.
2-15
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Response; It is impracticable to control emissions from underground
tanks with internal floating roofs. Emissions from these tanks can be
controlled with vapor recovery or disposal systems designed and operated
in compliance with these standards. While the cost effectiveness of vapor
recovery or disposal systems in these isolated instances may be high, cost
effectiveness is not a measure of economic impact. Rather, it is a
measure of the cost efficiency of controlling subclasses of vessels. The
overall cost of these standards is a net credit. Additionally, above-
ground internal or external floating roof tanks equipped with the controls
required by the standards could be constructed in lieu of underground
storage vessels. Therefore, the Agency has decided not to include this
exemption in the promulgated standards. It should be noted that the
exemption does continue for vessels constructed after the date of proposal
for Subpart K but prior to the proposal of Subpart Kb.
Comment: One commenter (IV-D-5) contended that the BID does not
support the inclusion of underground storage vessels, particularly those
smaller than 100 m (26,000 gal) in capacity. The commenter also noted
that emissions from these vessels are excessively costly to control.
According to the commenter, iristal.l at ion's storing VOL for use in manu-
facturing operations may need one or two horizontal, underground tanks as
large as 95 m3 (25,000 gal) to store material received from railroad tank
cars that have capacities up to 75 m (20,000 gal). The commenter
recommended that an exemption be included in the proposed standard for
underground storage vessels with capacities less than 100 m .
Response: Further discussions with the commenter revealed that the
commenter's primary concern was that some manufacturing plants may' not
have adequate space to install aboveground tanks. According to Factory
Mutual Research, adequate spacing of tanks is necessary to reduce the
possibility of the spread of fire from the tank initially involved to
exposed structures or adjacent tanks. For example, a 75-m3 (20,000-gal)
tank would have to be placed at least 7.5 to 15 m (25 to 50 ft) away from
buildings depending on the flammability of the liquid being stored. The
minimum tank-to-tank spacing is one-half the diameter of the largest tank;
4.3 m (14 ft) in the case of adjacent 75-m3 (20,000-gal) tanks. In
contrast, underground tanks may be located as close as 1.5 m (5 ft) to
building foundations and 0.6 m (2 ft) from other tanks and pipelines.5
2-16
-------
Aboveground tanks are a proven and safe method of storage, and there
appear to be no technical reasons why aboveground tanks could not be
installed in place of underground tanks when space permits. Furthermore,
it is expected that space would not be a problem at new plants because
they can be designed to allow sufficient space for aboveground tanks.
However, EPA cannot predict which existing facilities may have spacing
problems in installing new aboveground tanks. In cases where space is a
problem, the owner or operator may install underground tanks equipped with
add-on controls allowed by § 60.112b(a)(3).
The cost effectiveness of controlling emissions from a 113-m3
(30,000-gal) capacity underground tank is about $2s100/Mg.6 This assumes
the tank undergoes 10 turnovers per year, which is typical for the
commenter's industry. While this is higher than the cost effectiveness of
BOT control (i.e., floating roof) in comparable tanks ($310/Mg as shown in
Table 2-2), the overall cost of the standards is a net credit.1 There-
fore, the final standards will not be revised to include a blanket
exemption for underground storage vessels because adequate means of
complying with the standards (aboveground vessels or underground vessels
equipped with "add-on controls) exist. .
Comment: One commenter (IV-D-22) noted that horizontal tanks are
used widely in the synthetic organic chemical manufacturing industry
(SOCMI). The commenter said that because floating roofs cannot be used in
these tanks, there is a problem in applying the proposed standards to
them.
Response: The standards provide three fundamentally different
methods of compliance:
1. External floating roof tanks equipped with liquid-mounted or
mechanical shoe primary seals and a rim-mounted secondary seal;
2. Internal floating roof tanks equipped with liquid-mounted or
mechanical shoe primary seals or vapor-mounted primary and secondary seals
and gasketed fittings; or
3. A 95 percent effective vapor control system. Horizontal tanks
are typically small (volumes rarely exceed 113 m3 [30,000 gal]), and
because external floating roof tanks are rarely smaller than 492 m3
(130,000 gal), these horizontal tanks could not be constructed as new
2-17
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external floating roof tanks. However, the other options allowed by the
standard are suitable for vessels in the size range of horizontal tanks.
In subsequent discussion, the commenter agreed that vertical tanks
equipped with internal floating roofs could be used in place of horizontal
tanks although in instances such as separation processes horizontal tanks
were advantageous.
Additional information was obtained from the State of Texas on the
issue. Texas requires equipment similar to BDT (internal floating roofs)
for all new storage vessels with capacities of 95 m3 (25,000 gal) or
greater storing liquids with vapor pressures of 3.5 kPa (0.51 psia) or
greater and, thus, currently requires controls on vessels of concern to
the commenter. Texas Air Control Board (TACB) personnel have stated that,
in their permitting experience, there are very few circumstances in which
the tanks must tie horizontal. If a horizontal tank is used, the TACB
generally requires add-on control systems (carbon adsorption or thermal
g
oxidation).
Previous studies of storage in the chemical industry indicate that
add-on control systems are cost effective (less than $l,000/Mg) for tanks
with' volumes less than 151 m (40,000 gal) storing liquids with high vapor"
pressures. For example, as shown in Table 2-3, the average cost effec-
tiveness of a 95 percent efficient condenser for chloroform storage at
Q
chloroform production facilities is $630/Mg. This issue was further
analysed by examining the cost effectiveness of controlling a 113-m
(30,000-gal) horizontal tank as a function of turnover rate and filling
rate. While turnover rates of 170 times per year are typical for vessels
in this size range in the chemical industry, cases were analyzed assuming
5 and 10 turnovers per year. As shown in Tables 2-4 through 2-6, the
average cost effectiveness ranged from $650/Mg to $l,540/Mg.10 This range
is judged to be reasonable. The standards are achievable and, in many
cases, are cost effective even if atypical turnover rates are assumed and
if add-on controls are adopted. Furthermore, according to an organic
chemical manufacturing data base, only 0.22 percent of vessels with
volumes between 75 m3 and 151 m3 (20,000 gal and 40,000 gal) are used to
store liquids with vapor pressures between 27.6 kPa and 58.7 kPa (4 psia
and 8.5 psia). For vessels of all sizes, only 8 percent of fixed roof
2-18
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TABLE 2-3. COST EFFECTIVENESS OF 95 PERCENT EFFICIENT CONDENSER
FOR CHLOROFORM STORAGE AT CHLOROFORM PRODUCTION FACILITIES
(July 1982 $/Mg)
Net Emission
annual i zed reduction,
Plant Location cost, $/yr Mg/yr
Diamond Shamrock Belle, W. Va. 24,800 8.8
Dow Freeport, Tex. 30,000 2.2
Linden Moundsville, W. Va. 20,600 15.0
Vulcan Wichita, Kans. (16,000)a 68.6
Average
Cost
effec-
tiveness,
$/Mg
2,800
13,300
1,370
(230)
630b
( ) Indicates a net credit due to chloroform recovery.
Average cost effectiveness =
i net annualized costs
z emission reduction/yr
2-19
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TABLE 2-4. COST EFFECTIVENESS OF A 95 PERCENT
(MASS) EFFICIENT CONDENSER3'
Compound
n-Pentane
Cyclopentane
Isoprene
Ethyl Ether
Average
aBasis: 30,000
Vapor
pressure
at 70° F,
psia
8.433
5.240
9.668
8.702
Installed
capital
cost, Dec.
1982 $
15,800
11,400
17,100
15,800
gallon horizontal tank;
Total
annual -
ized
cost,
$/yr
5,100
3,620
5,570
5,100
Product
value,
$/Mg
430b
526C
530d
970e
10 turnovers/yr;
Cost
Emission effec-
reduc- tive-
tion, ness,
Mg/yr $/Mg
4.0 .
2.3
4.6
4.3 i
filling
850
1,050
680
220
650
rate =
.100 gal/mi n.
"Quoted December 21, 1984, by Ashland Chemical Company converted to
December 1982 dollars.
°Quoted December 21, 1984, by Phillips Chemical Company converted to
.December 1982 dollars.
aQuoted December 21, 1984, by Research Triangle Institute converted to
1982 dollars.
eQuoted from December 17, 1984, Chemical Marketing Reporter, converted
to December 1982 dollars.
2-20
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TABLE 2-5. COST EFFECTIVENESS OF A 95 PERCENT
(MASS) EFFICIENT CONDENSER3'
Compound
n-Pentane
Cyclopentane
Isoprene
Ethyl Ether
Average
aBasis: 30,000
Vapor
pressure
at 70°F,
psia
8.433
5.240
9.668
8.702
Installed
capital
cost, Dec.
1982 $
15,800
11,400
17,100
15,800
gal Ton horizontal tank;
Total
annual -
ized
cost,
$/yr
5,100
3,620
5,570
5,100
Product
value,
$/Mg
430b
526C
530d
970e
5 turnovers/yr;
Emission
reduc-
tion,
Mg/yr
3.2 1
1.7 1
3.6 1
3.4
1
fill-ing rate
Cost
effec-
tive-
ness,
$/Mg
,160
,600'
,020
530
,000
=•
100. gal/mi n.
"Quoted December 21, .1984, by Ashland Chemical Company converted to
December 1982 dollars.
cQuoted December 21, 1984, by Phillips Chemical Company converted to
December 1982 dollars.
dQuoted December 21, 1984, by Research Triangle Institute converted to
December 1982 dollars.
eFrom December 17, 1984, Chemical Marketing Reporter, converted to
December 1982 dollars.
2-21
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TABLE 2-6. COST EFFECTIVENESS OF A 95 PERCENT
(MASS) EFFICIENT CONDENSER*'
Compound
n-Pentane
Cyclopentane
Isoprene
Ethyl Ether
Average
Vapor
pressure
at 70° F,
psia
8.433
5.240
9.668
8.702
Installed
capital
cost, Dec.
1982 $
25,700
19,100
28,100
25,700
Total
annual -
ized
cost,
$/yr
8,600
6,280 .
9,470
8,600
Product
value,
$/Mg
430b
526C
530d
970e
Emission
reduc-
tion,
Mg/yr
4.6
2.3
4.6 •
4.3
Cost
effec-
tive-
ness,
$/Mg
1,720
2,200
1,530
1,030
1,540
aBasis: 30,,000 gallon horizontal tank; 10 turnovers/yr; "filling rate =
,200 gal/mi n.
DQuoted December 21, 1984, by Ashland Chemical Company converted to
December 1982 dollars.
cQuoted December 21, 1984, by Phillips Chemical Company converted to
.December 1982 dollars.
"Quoted December 21, 1984, by Research Triangle Institute converted to
December 1982 dollars.
eFrom December 17, 1984, Chemical Marketing Reporter, converted to
December 1982 dollars.
2-22
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storage capacity in the industry is dedicated to storage of liquids with
vapor pressures between 20.7 kPa and 103.4 kPa (3 psia and 15 psia).2
Based on this information, it is reasonable to assume that only a very
small proportion of potential new sources of fixed roof tanks would be
affected by the standards. Therefore, no exemption for horizontal vessels
has been incorporated into the final rule.
2.1.3.2 Facilities Producing Beverage Alcohol.
Comment: One commenter (IV-D-14) requested that EPA grant an
exemption from the proposed standards for vessels used to store non-
industrial, distilled beverage alcohol. The commenter requested the
exemption for the following reasons: (1) producers of distilled spirits
are insignificant sources of VOC emissions, (2) the suggested control
technology would either be extremely damaging to the product as a food
item or would be proscribed by existing Federal regulations, and
(3) thecosts and other problems that would result from implementation of
the proposed standards would violate Executive Order 12291.
Response: The Agency concurs with the commenter that the proposed
control technologies required by these standards could contaminate
beverage alcohol, resulting in-a product with little or no market value.
Also, because beverage alcohol was exempted from the priority list as part
of the SOCMI source category (44 FR 49222) and because it is not a
petroleum liquid, storage vessels containing beverage alcohol are exempt
from the final standards. However, any storage vessels that are used to
store nonbeverage, fermented products are subject to the standards if they
are found to be affected facilities.
2.1.3.3 Vessels Located on the Outer Continental Shelf (PCS).
Comment: One commenter (IV-D-3) noted that the U.S. Department of
the Interior, not EPA, is authorized to regulate air emissions from oil
and gas operations on the OCS. It was recommended that VOL and petroleum
liquid storage vessels located on the OCS be exempted as affected
facilities for this reason.
Response: Under the Outer Continental Shelf Lands Act (OCSLA), the
Secretary of Interior is authorized to issue air emission regulations for
activities located on the OCS. However, the Agency does not construe this
authority as exclusive jurisdiction. Under the authority of the Clean Air
2-23
-------
Act, the Agency is required to control air emissions from new, modified,
or reconstructed sources, including sources on the OCS (see
Sections 4(a)(l) and 21(d) of OCSLA, 42 U.S.C. 1333(a)(l), 1347(d)).
Because of this authority, the Agency has decided not to exempt
specifically vessels located on the OCS from the final standards.
In any event, the final standards do exempt vessels that store
liquids prior to custody transfer as defined in § 60.111b, unless the
vessels have a design capacity greater than 1,589.7 m (420,000 gal). A
study of offshore oil and gas production facilities indicated that if a
platform has storage vessels, those vessels store liquids that have not
undergone custody transfer. Therefore, the Agency believes OCS vessels
are exempt from the standards via the custody transfer provision.
2.1.3.4 "Slop Oil," Wastewater, and Waxy, Heavy Crude Oil Storage
Vessels.
Comment: One commenter (IV-D-6) requested an exemption to the
recordkeeping requirements for tanks used to store a mixture of different
products ("slop oil"). The commenter said that the constantly changing
nature of the products and the associated vapor pressure in these vessels
would necessitate physical testing to determine vapor pressure as required
in the proposed standards. According 'to the commenter, these vessels
represent a small portion of the vessels at any one facility, and little
benefit, if any, would be gained by including them in the vapor pressure
recordkeeping requirements.
Response: The purpose of the vapor pressure determination is to
distinguish among the three possible classes of VOL's that are of
concern:
1. Those liquids with vapor pressures greater than or equal to a
control cutoff (27.6 kPa [4 psia.) for vessels with capacities of 75 m
[20,000 gal] or greater and 5.2 kPa [0.75 psia] for vessels with
capacities of 151 m [40,000 gal] or greater);
2. Those liquids that are exempt from all vapor pressure
recordkeeping provisions of the standards (less than 15 kPa [2.2 psia] for
vessels with capacities between 75 and 151 m3 [20,000 and 40,000 gal] and
less than 3.5 kPa [0.51 psia] for vessels with capacities of 151 m
[40,000 gal] or greater); and
2-24
-------
3. Those liquids for which monitoring, but not emission control, is
required (between 15 and 27.6 kPa [2.2 and 4 psia] for vessels with
capacities ranging from 75 to 151 m3 [20,000 to 40,000 gal] and between
3.5 to 5.2 kPa [0.51 to 0.75 psia] for vessels with capacities of 151 m
[40,000 gal] or greater).
For most chemical and petroleum products, the class to which a given
liquid belongs will be obvious. For instance, the vapor pressure, of No. 2
fuel oil will not exceed 5.2 kPa [0.75 psia], and, therefore, vessels
storing this liquid would be exempt from all except the monitoring
provisions of the standards.
Waste tanks with constantly changing mixtures pose a different
issue. While a range of possible vapor pressures will be known, constant
minor fluctuations in composition will prevent the determination of the
actual vapor pressure without extensive (perhaps daily) testing. However,
these fluctuations generally are not so large that, under normal operating
conditions, large daily changes in vapor pressure would be expected.
Extensive testing of these liquids would be unduly burdensome to industry
without providing a corresponding benefit. "Therefore, EPA sought an
alternative that would preserve the intent of the requirement without
>
being unreasonably burdensome.
Prior to construction of the vessel, the range of likely liquid
compositions will be known, as will the maximum monthly average storage
temperature. Given these, it is possible to estimate the vapor pressure
of the mixture by Raoult's law:
where Pt=the total vapor pressure
Pp=the vapor pressure component
Xn=the mole fraction of a component
As with all other liquids, if the anticipated liquid composition with the
highest vapor pressure is below the monitoring cutoffs, the vessel would
be exempt from the standards, and no additional monitoring is needed.
For these types of liquids, the provisions for monitoring have been
changed from those proposed. If the anticipated liquid composition is
2-25
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above the cutoff for monitoring but below the cutoff for controls, the
standards require a physical test of the vapor pressure initially and at
least once every 6 months thereafter. This testing is not costly (less
than $100) and would serve the intent of the proposed standards without
being burdensome.12 Records of the results will be kept, but reports will
be required only in the event the vapor pressure of the stored liquid
exceeds the threshold for controls.
Comment; One commenter (IV-D-16) requested that wastewater holding
vessels be exempted as affected facilities. The commenter noted that use
of holding vessels to retain wastewater after the organic liquids have
been removed in an oil-water separator is common practice in the petroleum
industry. According to the commenter, these holding vessels contain
liquids with low vapor pressures such that operational monitoring and
emission controls are inappropriate.
Response; The commenter has raised two issues. The first is the
control of wastewater tanks. The vo.lume and vapor pressure cutoffs have
been selected so that controls are cost effective, and the control of
vessels and-stored liquids meeting these criteria is reasonable regardless
of liquid type. Therefore, no exemption for wastewater tanks has been
adopted.
The second issue is the vapor pressure monitoring requirements for
these tanks. The previous comment and response deal with revised-require-
ments for waste tanks. These revised requirements are also reasonable for
wastewater tanks' and would reduce the recordkeeping burden for these
tanks. Therefore, the revised monitoring requirements will apply to all
waste tanks, including wastewater tanks.
Comment; One commenter (IV-D-7) requested that vessels storing waxy,
heavy crude oils be exempt from secondary seal requirements. According to
the commenter, secondary seals are inappropriate for use with waxy, heavy
crude oils due to potential operational and safety concerns.
Response; Tank vendors were contacted for further information on
this issue. The Agency has determined that the storage of heavy, waxy
crudes is a significant problem for EFR's equipped with secondary seals.
The main problem is that solid wax adheres to the shell as the deck is
lowered. The wax melts as the shell wall heats during the day and runs
2-26
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down the wall, over the secondary seal, and onto the deck. The wax is
flammable and presents a fire hazard, plugs drains, and fouls fire
protection equipment. It can also adhere the secondary seal to the shell,
thereby causing damage to the'seal when the deck position changes. The
relatively stiff secondary seal can also scrape solid wax off the shell
and throw it onto the deck as the deck is raised. As the wax melts, it
can cause the problems mentioned above.
However, IFR's can be used to store heavy, waxy crudes. According to
one vendor, IFR seals are softer and do not scrape wax off the shell. In
addition, IFR's may be equipped with roof-mounted fire protection systems
that will not be fouled by wax on the deck. Another vendor said that
heavy, waxy crudes are commonly stored in internal floating roof vessels
equipped with steam coils and an insulation jacket. This system keeps the
wax in solution and eliminates the problem of wax buildup on the tank wall
or seal system. Because these standards are achievable for heavy, waxy
crudes by using IFR's, the Agency has determined that no exemption for
these liquids will be included in the standards.
2-. 1.3.5 Negligibly Photochemically Reactive Liquids.
Comment: Two commenters (IV-D-13, IV-D-15) requested that negligibly
photochemically reactive liquids such as 1,1,1-trichloroethane and
methylene chloride be exempted from the proposed standards. One commenter
(IV-0-18) requested that these chemicals be listed as negligibly photo-
chemically reactive. One commenter (IV-D-15) claimed that previous VOC
standards have exempted these liquids. Another commenter (IV-D-23)
recommended that proposed standards list all VOC compounds to be included
and exempt VOC's that are negligibly photochemically reactive. The
commenter said that the inclusion of negligibly photochemically reactive
liquids could increase the control costs. One commenter (IV-D-3)
suggested that a listing of those compounds that are defined as VOC's be
referenced in the text.
Response: Previously, the EPA has determined that the following
11 compounds are negligibly photochemically reactive:
1. Methane;
2. Ethane;
3. Methylene chloride (dichloromethane);
2-27
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4. Methyl chloroform (1,1,1-trichloroethane);
5. Trichlorofluoromethane;
6. Dichlorodifluoromethane;
7. Chlorodifluoromethane;
8. Trifluoromethane;
9. Trichlorotrifluoroethane;
10. Dichlorotetrafluoroethane; and
11. Chloropentafluoroethane.
Because these compounds do not significantly contribute to the
formation of ozone, the Agency agrees that the control of vessels storing
these compounds would not reduce ambient ozone levels and has, therefore,
exempted vessels that store only these compounds from the final rule.
Because this list of compounds will change from time to time as research
continues, no list of exempt compounds is included in the final rule.
Rather, the approach that has been taken is to exempt each compound that
has previously been declared negligibly photochemically reactive in
previous Federal Register notices.
Regarding the request that a, list of VOL's and/or VOC's be provided
as part of the" final s-tandard, it should be noted that, in essence, the--
commenters are requesting that a list of all organic compounds except
those determined to be negligibly photchemically reactive be provided as
part of the final standards. The Agency sees no reason to add such a list
to the final standards and feels that the provisions determining applic-
ability of the NSPS are adequate without it. Therefore, no such list has
been incorporated into the final rule.
2.1.3.6 Production and Process Vessels.
Comment: One commenter (IV-D-23) requested that production and
process vessels having an intermediate function, not raw material or
product storage, be exempted from the proposed standards. The commenter
said that estimates of working losses for these vessels were incorrectly
based on "total throughput." The commenter said that "net throughput" is a
more realistic measure of turnovers. The commenter stated that the
control technology may not be cost effective for production and process
vessels. The commenter recommended that EPA reevaluate the standards
using net throughput.
2-28
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Response: The EPA agrees that total throughput (tank volume divided
into annual liquid throughput) may not accurately reflect the actual
change in liquid level (net throughput), which is an underlying mechanism of
working losses. The commenter provides an example of a 75-m (20,000-gal)
tank that would undergo 689 turnovers per year as measured by total throughput
but only 87 turnovers per year as measured by net throughput.
A representative of the Texas Chemical Council contended that
turnovers based on total annual throughput overestimate turnovers based on
net annual throughput by 75 to 80 percent. However, in this instance,
even turnovers based on net annual throughput would range from 55 to
100 per year for tanks in the size range covered by the standards.^
Controls on these vessels would be cost effective at these turnover
rates. Further discussions with the commenter (IV-D-23) revealed that
only 14 percent of the process tanks in use at the commenter1s plant would
come under the size and vapor pressure cutoffs of the standards if they
were new sources. Therefore, the Agency has determined that constant
level.tanks do not typically exhibit low turnover rates nor do they
comprise a significant portion of tanks at chemical plants.
In further evaluating this issue, the EPA examined the cost
effectiveness of controlling the sample tank cited by the commenter.
Because the commenter did not fully specify the necessary tank parameters,
the emission reduction obtained by BOT controls was evaluated for working
losses, based on net throughput, and was assumed to be 90 percent. To be
conservative, a welded steel deck with Teflon®, liquid-mounted, primary
seals was costed as the control technology. Tank diameter was assumed to
be 4.5 m (15 ft), and product value was assumed to be $360/Mg. The
calculated cost effectiveness for controlling this tank is about
$910/Mg. In the case cited by the commenter, the cost effectiveness of
controls is still reasonable even when calculated for actual turnovers
based on net throughput.
In previous studies by the EPA, model plants were developed for
storage associated with selected chemical process. Some of these models
include "constant level" tanks (tanks with high total throughputs but low
net throughputs). These tanks were evaluated for control, and the results
are presented in Table 2-7.I6»17 The average cost effectiveness was found
2-29
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to be $210/Mg. Although there are Instances where the cost-effectiveness
value is high, the average cost effectiveness of controlling constant
level tanks is reasonable. These costs are also representative of
production and process tanks that are operated typically as constant level
tanks. Therefore, the final standards do not provide an exemption for
constant level tanks.
2.1.3.7 Bulk Plant Storage Vessels
Comment: One commenter (IV-D-39) requested that the impact of the
standards on small businesses be evaluated. The commenter was concerned
that members of the Petroleum Marketers Association (particularly owners
or operators of bulk gasoline plants) would be unable to raise the capital
necessary to comply with the required controls.
Response; According to the Small Business Administration's criteria
for small businesses, bulk plants may be classified as such because they
typically have fewer than 500 employees. The economic impacts of the
standards on model bulk plants were examined to see if adverse impacts
(closure of the facility or inability to construct the new source) could
be ruled out. While the capital costs' of controls represent only
5 percent of total capital cost for a new model facility, the capital
costs of control for replacing or adding an individual tank are
significant and may be 50 percent of the total capital cost required to
install a new individual tank. The bulk plant industry is declining due
to competition from bulk terminals, withdrawal of major oil companies from
the bulk plant business, and other reasons; and it is possible that the
impact of further regulation would be to accelerate closures. Therefore,
it was determined that a potential adverse economic impact exists.
Although an Agency study indicates that the cost effectiveness of
controls is reasonable for typical facilities ($520/Mg), the economic
1 A
impact may not be reasonable. The Agency was unable to quantify the
profitability of bulk plant firms, and no data are available to prove that
these firms have access to sufficient capital to install controls. Even
firms that are part of integrated operations may not be able to divert
capital from more profitable operations to bulk plant operations.
Therefore, the Agency was unable to ascertain how many of the plants that
would add or replace tanks would suffer an adverse economic impact due to
2-31
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the inability to finance the capital costs of controls. Furthermore, bulk
plants are an identifiable class of vessels and an exemption for this
class would not affect the objectivity and enforceability of the
standards. For these reasons, the Agency has decided to exempt bulk
gasoline plants from the standards.
This change in the regulation from proposal only affects those plants in
attainment areas. Plants located in nonattainment areas would have been
exempted in any case because the control technology required by the SIP's
in these areas (vapor balance systems) is incompatible with BDT. The bulk
plant industry is also part of the gasoline marketing source category
(Petroleum Transportation and Marketing [40 CFR 60.16]), and the decision
whether to regulate emissions from these vessels at bulk plants is being
made in a regulatory decision package for that category.
2.2 EMISSION CONTROL TECHNOLOGY
2.2.1 External Floating Roof Vessels (EFR's)
Comment: Two commenters (IV-D-18, IV-D-21) noted that hygroscopic
VOL's cannot be stored in EFR's because of the potential contamination of
the liquids by water.
Response: The Agency agrees that not every liquid covered by the
standards is appropriate for storage in EFR's. Such liquids may be stored
in internal floating roof vessels (ventilated or nonventilated) or in
fixed roof tanks equipped with vapor recovery or disposal systems.
Comment: One commenter (IV-D-18) stated that industry experience
with secondary seals is limited and that there is uncertainty regarding
the effective life of the seals. The commenter also requested that EPA
acknowledge a potential safety hazard from the formation of a vapor space
between the primary and secondary seal.
Response: The commenter is correct in stating that there may be some
uncertainty in the lifetime of secondary seals; the actual lifetime may be
longer or shorter than the 10 years estimated at proposal. Comments
received on the draft Control of Volatile Organic Compound Emissions from
Volatile Organic Liquid Storage in Floating and Fixed Roof Tanks (CTG),
August 1983, suggested that vapor-mounted primary seals On an internal
floating roof would have a lifetime of 10 years or more in the more severe
chemical services. Because the construction of the seal systems is
2-32
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similar to that of secondary seals used on EFR's, it is reasonable to
assume a 10-year life on secondary seals for EFR's as an average.
The Agency has determined that adequate technology exists and is
commonly employed to operate EFR's with double seals in a safe manner.
Although specific data are not available for EFR's equipped with
double-seal systems, the fire and explosion hazard is greatly reduced by
use of floating roofs in comparison to fixed roof tanks because the
floating roof eliminates vapor space. The reduced hazard is substantiated
by Factory Mutual Research fire loss experience for a 13-year period from
1962 to 1974. Fixed roof tanks were involved in 53 percent of all losses
while floating roof tanks were involved in only 34 percent. Signifi-
cantly, 47 percent of fixed roof tanks were totally destroyed, and an
additional 50 percent suffered major damage. Only 12 percent of floating
roof tanks were totally destroyed, and 36 percent suffered roof, ring, or
shell damage. Unlike fires in fixed roof tanks, most fires in floating
roof tanks were extinguished by portable foam or water hose streams before
serious damage occurred. Therefore, the Agency concludes that there are
no safety hazards associated with floating roof tanks beyond those.
normally experienced by industry.
2.2.2 Internal Floating Roof Vessels (IFR's).
Commenters representing the chemical industry were concerned that
IFR's and some liquid-mounted primary seals are not an appropriate or
proven, safe control technology for the range of chemicals stored.
Comment: Three commenters (IV-0-9, IV-D-15, IV-D-22) noted that
vented IFR's may not be the best choice of storage vessel in cases where
the stored liquid must be protected from moisture or oxygen. One
commenter (IV-D-22) cited chemical products such as chlorinated solvents
that may be contaminated by exposure to moist ambient air. One commenter
(IV-D-15) noted that vented IFR's would greatly enhance the cost of inert
gas pads.
Response: These comments are based on the premise that the IFR
required in § 60.112b(a)(1) must be vented. The Agency agrees that
ventilating tanks storing liquids which must be protected from contact
with ambient air is not wise. Neither the proposed nor the promulgated
standards require the IFR to be vented. The IFR may be ventilated or
2-33
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nonventHated, padded or unpadded, according to the preference of the
owner or operator, without affecting the compliance status of the tank.
Therefore, the requirement for an internal floating roof will impose no
additional contamination problems, safety problems, or gas padding costs
over normal industry practice. No changes to the standards have ;been
made.
Comment; Three commenters (IV-D-9, IV-D-15, IV-D-22) stated that use
of the floating roof itself is incompatible with storage of highly
corrosive liquids. According to two of the commenters (IV-D-15, IV-D-22),
to prevent corrosion damage, the vessel may either be lined with plastics,
fluoropolymers, or synthetic materials, or it may be constructed with
fiberglass reinforced plastic (FRP). These commenters state that such
materials are unable to withstand the abrasion which is incipient in the
operation of floating roofs. One commenter (IV-D-15) recommended that an
alternate control technology be defined or that lined tanks be exempted.
Response; Regarding the abrasion of the tank liner, internal
floating roof seals are typically made of soft materials and are softer
than common liners. The seals do not exert much compressive force against
the tank sidewall. The anticipated point of wear would be- the seal and
not the tank liner. Internal floating roofs have been installed in lined
tanks and have operated properly without excessive wear to- the liner.
Therefore, no exemption for lined tanks, has been incorporated into the
final standards.
Fiberglass reinforced plastic tanks are used by some tank operators
to store corrosive liquids (chlorinated solvents, acids, and bases).
These tanks are generally lined with a corrosion barrier composed of a
thin layer of resin. Floating roofs are not used in these tanks because
the roof seals could damage the resin layer such that a leak or structural
damage results. However, stainless steel tanks equipped with internal
floating roofs may be substituted for FRP tanks, or emissions from FRP
tanks may be controlled by use of a closed vent system and 95 percent
effective control device. Therefore, because adequate control
alternatives are available to owners or operators of FRP tanks, no
revisions have been made to the standards.
2-34
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Comment; One commenter (IV-D-9) questioned whether ventilation in
IFR's is adequate to prevent an explosion hazard. Another commenter
(IV-D-21) said that the proposed standards should recognize that the use
of IFR's could promote the formation of explosive vapor mixtures above the
floating roof. Another commenter (IV-0-22) noted that, by design, the
product stored in an IFR is isolated from any roof-mounted deluge system,
thus reducing the probability of early control of any fire that occurs.
Response: The Agency has determined that the proposed standards do
not pose a safety hazard. A representative of the Texas Chemical Council
(IV-D-9) has stated that his company's (E. I. Dupont) safety personnel had
reviewed the proposed standards and did not believe that the required
controls would pose a hazard. Data from vendors indicate that the lower
explosive limit was never reached in tests on a noncontact internal
floating roof in vented tanks storing a wide variety of products. l It
appears that there are no additional safety hazardous associated with the
IFR beyond those hazards normally accepted by the industry.
As stated previously, there is no requirement that IFR's be vented.
Vessels equipped with internal floating roofs may be vented or nonyented
and blanketed or unblanketed. •
Regarding isolation from any roof-mounted deluge system, vendors of
internal floating roofs and Factory Mutual Research Standards have stated
that foam distribution systems have been used successfully against fires
in internal floating roof tanks.5 Foaming the deck closes off the oxygen
supply so that any vapor space under the deck will quickly be deficient in
the oxygen necessary to support a fire.
Comment: One commenter (IV-D-9) questioned the accuracy of the API
emission equations for IFR's. The commenter discussed the accuracy of the
equations when applied to vented vessels smaller than 20 feet i'n diameter,
which are more common in the chemical industry. The commenter said that
the equations were more accurate for the larger vessels typically found in
the petroleum industry. The commenter requested that EPA consider the
nonvented IFR because the wind speed, which affects the air flow pattern
through the vents, would not be a factor, and emissions should be
reduced.
2-35
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Response: Overall, the emission test data on IFR's indicate that there
is no significant dependence on wind speed. Wind-induced ventilation
removes vapors that have already escaped the space confined by the deck,
seals, or fitting covers, and it does not appear to cause these emissions.
It is expected that the different ventilation patterns in smaller tanks
would not play a significant role in generating emissions especially if
vapor space is minimized by employing liquid-mounted seals or pressure
differentials are prevented by using tight fitting vapor-mounted primary
seals and secondary seals. Therefore, EPA believes that the current
emission equations are adequate to support the selection of BDT for both
small and large tanks.
2.2.3 Add-on Control Options
Comment: Two commenters (IV-D-13, IV-D-22) discussed alternate
control options. One commenter (IV-D-13) asked if use of control devices
such as carbon adsorption, refrigerated condensers, and thermal oxidizers
are allowed if they achieve 95 percent emission reductions. Another
commenter (IV-D-22) noted that an alternate control option, vent gas
condensation, is commonly used and that its efficiency may be enhanced
through the use of product cooling and tank insulation. The commenter
requested that EPA consider allowing this control option.
Response: Any type of closed vent system and control device such as
a carbon adsorber, vent gas condenser, or thermal oxidation unit that is
designed and operated to reduce inlet VOC emissions by 95 percent or
greater is in compliance with § 60.112b.
Product cooling and tank insulation could be used to enhance the
effectiveness of condensation systems. The standards are based on the
vapor pressure of the liquid at its storage temperature. Therefore, the
use of this strategy is not prohibited by the standards.
Comment; One commenter (IV-D-9) requested that EPA allow use of
pressure/vacuum (conservation) vents. The commenter said that in vessels
with zero turnovers, a conservation vent is more effective than a vented
IFR. Another commenter (IV-D-22) stated that conservation vents, coupled
with tank insulation and product cooling, provide a reasonable level of
control in many circumstances.
2-36
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Response; Conservation vents may have some effect in controlling
breathing losses from fixed roof vessels. However, the ability of a
conservation vent to reduce emissions in the chemical and petroleum liquid
industries is not well established. Additionally, VOC emissions due to
working losses significantly outweigh emissions due to breathing losses,
particularly as the number of tank turnovers increases.
As an example, the model tank used in the Volume I BID (volume of
606 m3 [160,000 gal], diameter of 9.1 meters [30 ft], 50 turnovers per
year, vapor pressure of 6.9 kPa [1 psia], and molecular weight of 80) has
total emissions of 6.22 Mg/yr as a fixed roof tank. Only 0.88 Mg/yr
result from breathing losses. Therefore, if a conservation vent reduced
breathing losses to zero, the emission reduction would total about
14 percent. This is in sharp contrast to the 96-percent reduction
obtained by equipping the tank with an internal floating roof.1
The scenario of zero turnovers presented by the commenter is
unrealistic. Tanks are not permanent storage facilities for chemical
products and, therefore, do not have zero throughput. Tanks in the
chemical industry average about 60 turnovers per year in the 600 m3
(160,000 gal) size range and about 150 turnovers in the 151 m3
(40,000 gal) size range. Therefore, the final standard does not allow the
use of conservation vents in lieu of the specified controls.
The combination of conservation vents and product codling might be,
in specific instances, approved by EPA as an alternative means of emission
limitation under § 60.1l4b. However, it would be the obligation of the
applicant to demonstrate that the proposed controls are equivalent to
those promulgated in § 60.112b.
The test program that is currently being conducted by API will
examine the emission equations for fixed roof vessels. The results of
this test program will be used to evaluate the potential contribution of
conservation vents to an emission reduction program in the next review of
the standards and may be useful in supporting an application under
§ 60.114b.
Comment: One commenter (IV-D-23) discussed the fugitive emission
monitoring requirement for closed vent systems. The commenter questioned
the cost effectiveness of the fugitive emission requirement for two
2-37
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reasons: (1) the fugitive emission level is low and (2) a product
recovery credit cannot be claimed because the "recovered" material ends up
in the waste stream. The commenter requested that all references to fugitive,
emission monitoring be reevaluated for their cost effectiveness. ,
If the requirement for control of fugitive emissions from a closed
vent system is retained in the standard, the commenter recommended the
following:
1. Fugitive emission control should be limited to a new, modified,
or reconstructed closed vent system. The commenter noted circumstances in
which a new, modified, or reconstructed storage vessel may have emissions
controlled by an existing closed vent system that also controls other
existing sources. The commenter stated his belief that it is not the
intent of EPA to apply the standards to an existing facility of this
type.
2. The requirement referred to as the SOCMI equipment leak standard,
40 CFR Part 60, Subpart VV, § 60.485(b), should be subject to all the
limitations and exceptions contained in Subpart VV. ;
3. The commenter noted that the VOL standards are more restrictive
than the SOCMI standards with respect to leaks from valves and pumps. The
commenter said that the 500 ppm cutoff in the proposed standards is more
restrictive than the 10,000 ppm cutoff in the SOCMI standards. The
commenter requested that a 10,000 ppm cutoff be adopted for valves and
pumps in the proposed VOL standards to maintain consistency with the SOCMI
standards.
Another commenter (IV-D-13) requested further information on. the
basis for using 500 ppm above background as the level of no detectable
emissions for closed vent systems. The commenter questioned whether
readings at this level are consistent with current instrument capabilities
and whether the requirement is consistent with leak rates set under
fugitive emission rates.
Response: The commenter (IV-D-23) misunderstood the intent of the
fugitive emission requirement in Subpart Kb. The requirement is not
intended to control fugitive emissions but rather to ensure that an
alternative to BDT is operated effectively. The only adopted provision of
Subpart VV is the no detectable emissions limit. Valves and pumps are not
covered by Subpart Kb. ',
2-38
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The commenter (IV-D-23) questioned the applicability of the fugitive
emission requirement in circumstances where a new, modified, or recon-
structed storage vessel is controlled by an existing closed vent system
and control device. If the owner or operator chooses to control a new
•source through the use of a closed vent system and control device, the
control equipment must be operated and maintained to conform to the
requirements of the standards. In this case, these requirements include
meeting the fugitive emission leak standards as specified in
§ 60.112b(a)(3)(i). A new fixed roof storage vessel is not considered to
be in compliance with these standards when it is linked to an existing
closed vent system and control device unless the existing equipment is in
compliance with § 60.112b(a)(3)(i). Therefore, the Agency has determined
that no changes are necessary in the final standards.
The comment that a 500 ppm above background cutoff for allowable
detectable emissions is more restrictive than the cutoff level allowed
under the SOCMI standards is erroneous. The SOCMI standards require that
closed vent systems shall be designed and operated with no detectable
emissions indicated by an instrument reading of less than 500 ppm above
background and visual inspections. This is the'.provision adopted under
Subpart Kb, The 10,000 ppm cutoff referred to by'the.commenter only
applies to the requirements in the SOCMI standards for valves and pumps.
This cutoff is not applicable to Subpart Kb. The Agency has determined
"that adequate instrumentation exists to determine emissions below 500 ppm. •
Comment: One commenter (IV-D-9) recommended modification of the
requirement for a 95 percent reduction in emissions when a closed vent
system and control device are used. The commenter recommended that, in
circumstances where vented IFR's cannot be used, the control device should
instead be designed and operated to achieve an emission reduction equiva-
lent to that calculated for the affected storage vessels by the formulas
in AP-42 and API Bulletin No. 2519 or by a reduction of 95 percent,
whichever is lower.
Response: The three fundamentally different techniques for compliance
allowed by these standards are not equivalent in terms of emission rate.
In the process of developing the requirements for internal floating roofs,
each component of the roof was evaluated for emission reduction and
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cost. Thus, a BDT for internal floating roofs was developed. The
calculated emission reduction obtained by a BDT internal floating roof
varies from about 50 percent up to 99 percent over a fixed roof tank
depending on the number of turnovers, vapor pressure, and molecular weight
of the stored material. The reduction obtained in typical tanks is about
95 percent.
Properly designed and operated vapor control systems can reduce VOC
emissions by 95 percent. This is similar to the reduction typically
achieved by the BDT internal floating roof. If vapor recovery systems are
to be used, they should be designed and operated to be as efficient as
possible. Installation of vapor control systems designed to function at
low efficiencies would increase emissions unnecessarily. Therefore, the
final standards do not incorporate the provision requested by the
commenter.
Comment: While one commenter (IV-D-2) stated support for the use of
flares as a control device, three other commenters (IV-D-6, IV-D-9,
IV-D-12) stated that the flare exit velocity limitations are unduly
restrictive and suggested that they be reviewed in light of the latest •
information from the Chemical Manufacturers Association (CMA) and EPA.
Two commenters (IV-D-9, IV-D-12) said that the velocity specifications are
identical to those proposed in the SOCMI equipment leak NSPS and suggested
that both the SOCMI and the proposed VOL standards be revised to encompass
a consistent set of limitations based on a recently completed study
showing 98 percent or better destruction efficiencies at velocities
greater than the existing velocity limitation. One commenter (IV-D-9)
suggested a public comment period on flare operation limitations.
Response: The flare exit velocity limitations have been reviewed by
EPA in the time since the standards were proposed. New data obtained by
an EPA test program showed that VOC destruction efficiencies of 98 percent
or better are achievable using higher exit velocities when the net heating
value of the gas being combusted is greater than 37.3 MJ/scm
(1,000 Btu/scf). In order to avoid having a large number of regulations
with indentical flare specifications, the Agency has promulgated the
addition of uniform flare specifications to § 60.18 of the General
Provisions (51 FR 2699, January 21, 1986). The VOL standards have been
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revised to incorporate these provisions as well. The specifications limit
flare exit velocity of steam-assisted and nonassisted flares to 18.3 m/s
(60 ft/s) unless the net heating value of the gas being combusted is
greater than 37.3 MJ/scm (1,000 Btu/scf). In this latter case, exit
velocities may be between 18.3 m/s and 122 m/s (400 ft/s). The specifi-
cations also permit the owners to operate the flare at a prorated maximum
exit velocity (based on the net heating value of the gas being combusted)
so long as it is less than 122 m/s (400 ft/s) but greater than 18.3 m/s
(50 ft/s).
2.2.4 Column Fittings
Comment; Three commenters (IV-D-7, IV-D-8, IV-D-20) found the
required use of flexible fabric sleeve seals on column penetrations to be
restrictive and recommended that EPA also allow the use of gasketed
sliding covers. They noted that flexible fabric sleeve seals are a
fitting design unique to a single manufacturer and are not generally
available. They also noted an insignificant difference in overall
emission reduction (0.1 to 0.2 percent) when flexible fabric sleeve seals
are used in place of gasketed sliding covers. Two of the commenters
(IV-D-7, IV^D-8) stated that the use of "built-up" columns, which are
currently in wide-spread use, is 'disallowed under the proposed standards
because sleeve seals can only be .used with pipe columns. One commenter
(IV-D-20) discussed the potential for damage and maintenance repair
problems with use of sleeve seals which could result in lengthy downtime.
One commenter (IV-D-7) pointed to an apparent miscalculation in the
BID resulting in a 50-percent overestimation in the emission reduction
associated with controlled versus uncontrolled fittings. According to the
commenter, a miscalculation would place an undue emphasis on maximizing
fitting controls and, therefore, would restrict column and seal designs
that should be allowable.
Two commenters (IV-D-7, IV-D-18) said that slotted gauge/sample poles
are frequently used and recommended that they be allowed in the final
rule.
Response: Flexible fabric sleeve seals are currently available only
on contact decks. It is not the intent of the Agency to prohibit the use
of noncontact decks with this fitting requirement. While the annualized
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cost of redesigning a noncontact deck to allow the adoption of flexible
fabric sleeve seals is not known, the Agency has determined that it is
highly unlikely that noncontact decks could be redesigned and flexible
fabric sleeve seals installed cost effectively. Alternatively, gasketed
sliding covers are widely available and may be employed on both contact
and noncontact decks. Therefore, the Agency has decided to revise the
i
proposed regulations to allow the use of either flexible fabric sleeve
seals or gasketed sliding covers.
The EPA has reevaluated the costs to control emissions from
fittings. These controls are estimated to cost $500 (4 percent of the
cost of the deck) for a typical vessel with a diameter of 9.1 m (30 ft).
The cost effectiveness of controlling emissions from fittings on this
vessel storing a typical VOL is $990/Mg. The capital cost of controlling
fitting emissions on a typical 30.5-m (100-ft) diameter vessel storing
gasoline is $1,677, and the cost effectiveness is $330/Mg.22 The Agency
has determined that these values are reasonable, and, therefore, no
changes have been made to the requirements for fitting controls.
The standards will not be revised to allow the use of slotted
gauge/sample poles. The. BDT for sample pipes and wells is the slit fabric.
seal with 10 percent open area. Slit fabric seals are widely available at
no additional cost and achieve a greater emission reduction than slotted
gauge/sample poles and are included in the above evaluation.
2.2.5 Alternative Means of Emission Limitation
Comment; Two commenters noted the possibility of construction delays
resulting from EPA granting permission to use technology that is
equivalent to the technologies allowed in the proposed standards. One
commenter (IV-D-7) requested that EPA be required to grant permission
within 90 days of receipt of a request rather than allowing the ;
unspecified period in the proposed standards. A second commenter,
(IV-D-22) requested that State agencies operating with approved State
Implementation Plans be allowed to grant permission.
Response: No changes will be made in the language regarding
alternative means of emission limitation. This NSPS is an equipment
standard (§ lll(h) of the Clean Air Act) because it is impracticable to
measure emissions. Any future requests for permission would most likely
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be made for a new type of roof or seal. A straightforward emissions
measurement is not possible in these cases; and it is likely that the
determination could involve complex modeling, the evaluation of new test
methodologies, or other time consuming tasks. A 90-day time period is not
sufficient to evaluate the proposed equipment, provide notice and
opportunity for a hearing, and publish a decision. The amount of time
needed to make a determination can vary greatly depending on the
complexity of the application. Therefore, the time in which the Agency is
to grant permission is left unspecified in the final standards.
No changes have been made in the standards to allow the States to
grant permission. Even when States have been delegated NSPS authority,
they have not been delegated the authority to grant permission. The
reason for this policy is that different States could come to opposite
conclusions -on the equivalency of a new technology. This would be both
confusing and contrary to the need for uniform, national performance
standards for new sources.
2.3 RECORDKEEPING, REPORTING, AND INSPECTION REQUIREMENTS
2.3.1 Recordkeeping and Reporting Requirements
Comment: Several commenters requested changes in the provisions
requiring operators to maintain records showing the dimensions and
capacity of storage'vessels larger than or equal to 40 m3 (10,000 gal).
Four commenters (IV-D-2, IV-D-10, IV-D-16, IV-D-39) said that the
recordkeeping provision is without purpose or benefit because vessels.that
are less than 75 m3 (20,000 gal) are not subject to the control
requirements. One commenter (IV-D-10) said that the inclusion of any sort
of requirement on vessels down to 40 m in capacity would generate both
demand for performance standards for these vessels and more permitting
requirements- at the State or local level. One commenter (IV-D-4)
suggested that the regulation only apply to storage vessels with a
capacity greater than 70 m3 (18,500 gal), while three others (IV-D-10,
IV-D-16, IV-D-39) suggested that the cutoff for recordkeeping and control
be the same level (75 m3 [20,000 gal]).
Response: The Agency has required the owner/operator of tanks
between. 40 m3 and 75 m3 (10,000 gal and 20,000 gal) to retain a record of
the size of the tank to aid in enforcement of the standards. The records
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are necessary for enforcement because they remove any ambiguity in
identifying vessels that are close to the control cutoff. According to
one commenter (IV-D-10), the recordkeeping requirement is not burdensome
because such records are routinely maintained. The EPA judges that it
should not refrain from adopting appropriate requirements because of
speculation that they may inspire further regulation.
Comment; One commenter (IV-D-13) stated that the reporting ''
requirements are burdensome and time consuming for both the regulated
community and the Agency. The commenter recommended that the reporting
requirements be replaced with a requirement that the regulated community
maintain reasonable records of performance.
Response: The Agency has determined that the reporting requirements
are reasonable and do not place an undue burden on the regulated community
or the Agency. Reports are submitted only in the event of a system
failure and, given the expected low probability of system failure, the
reports will not be an undue burden. The reporting requirement is
essential in enforcing the standards.
Comment; One commenter (IV-D-23) said that the requirement that an
operator of a vessel equipped with a closed vent system (other than a'
flare) submit an operating plan for approval to the Administrator is
burdensome. The commenter noted that under the-General Provisions
(§ 60.8), a performance test is already required within 60 to 180 days of
start-up to verify the efficiency of the system. The commenter said that
the testing requirement alone should be sufficient to demonstrate
compliance and that submittal of an operating plan for approval should not
be required.
Response; It was not the intent of the Agency to require a
performance test for these standards. Emissions from fixed roof tanks are
variable and are often at rates that are too low to measure. When liquid
is entering a vessel, the liquid surface rises, forcing vapors above the
liquid surface out of the vessel. While this is occurring, the vapor flow
rate and the emissions are large. When liquid is exiting the vessel, the
liquid surface falls, and the resulting pressure differential sucks air or
a blanketing material into the vessel. During these operations, vapor
flows into the storage vessel and results in no atmospheric emissions.
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When the liquid level is held constant, pressure differentials resulting
from diurnal temperature variations expel vapors at very low flow rates at
intermittent times during the cycle.
Certain components of uncontrolled emissions have been measured in
very specialized tests conducted by EPA and industry. Total emissions
have not been measured, however, and to do so would require that the
operation of the vessel be strictly controlled during the testing
period. Because of methodology problems, it may not be possible to
measure both the flow rate and the concentration simultaneously. This
would cast doubt on the accuracy of the measurement. In any case, testing
would be extremely expensive for individual compliance determinations.
For these reasons, it was concluded that it was impracticable to measure
the emissions exiting the tank.
For the same reasons, it would be impracticable to measure the
emissions captured by the closed vent system or entering the control
device. Therefore, it was concluded that reduction efficiency measure-
ments are not feasible for closed vent systems and control devices, and
the format of the standards for closed vent systems and control devices is
•an equipment standard. Therefore, no" performance test is required.
Inspection, maintenance, and repair requirements are necessary to
ensure the proper operation and integrity of control equipment meeting the
•standards. Submittal of an operating plan is essential to demonstrate
compliance with the standards, and the requirement has been retained in
the final standards. The requirement will be modified, however, to
specifically exempt storage vessels from the General Provision requirement
for a performance test (§ 60.8) for the reasons discussed above.
2.3.2 External Floating Roof Vessel (EFR) Inspection Requirements
Comment: One commenter (IV-D-11) said that annual measurements of
secondary seal gaps on EFR's are excessive and that these measurements
should be conducted every 5 years to coincide with measurement of the
primary seal gap.
Response; The time and resources required to conduct these
inspections are minimal. The only way to ensure seal integrity and
compliance with the standards is through these inspections. Therefore,
the annual inspection requirement has been retained in the final
standards.
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Comment; Two commenters (IV-D-7, IV-D-18) requested that EPA allow
the initial seal gap measurements to occur during the hydrostatic testing
of the vessels or within 60 days (IV-D-7) or 6 months (IV-D-18) of the
initial fill.
Response; The Agency has revised the final standards to allow the
seal gap measurements to occur during hydrostatic testing. Measurements
conducted during the hydrostatic testing would reveal any seal gaps that
would be discovered during an inspection after the initial fill. The
60-day time frame to conduct the inspection after the initial fill is
reasonable considering that the inspection takes less than a day.
Therefore, the time frame after the initial fill has not been changed from
the proposed standards.
2.3.3 Internal Floating Roof Vessel (IFR) Inspection Requirements
2.3.3.1 Annual Visual Inspection.
Comment; One commenter (IV-D-9) said that an annual visual
inspection of IFR seals precludes the use of nonvented IFR's because of
the excessive time, materials, and manpower required to inspect the
vessels. The commenter said that the inspection would also violate
internal company safety rules* The"commenter suggested that IFR's with
primary and secondary seals be inspected internally at 5-year intervals.
If EPA were to approve a 5-year inspection interval, the commenter further
proposed that it be considered equivalent to an annual inspection of a
single-seal system. The commenter calculated that overall emission rates
due to seal failure are equivalent under the two options.
Response; After evaluating this issue, the Agency has determined
that it may not be possible to inspect all IFR's without emptying and
degassing the vessel. The Agency evaluated the commenter1s proposed
revision and has decided to revise the standards. If the operator equips
the vessel with a primary and a secondary seal and conducts an internal
inspection every 5 years, the controls are considered equivalent to a
single-seal system and annual visual inspection. Under the double-seal
system option, the addition of a secondary seal will reduce emissions
beyond the emission reduction achieved by a single-seal system, thus
offsetting the risk of increased emissions due to seal failure. In any
case, seal failure rates are generally quite low, and a major failure
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(such as a deck sinking) would be evident to the operator even in the
absence of an annual inspection because of a loss of material.
A worst-case analysis of the possible impact this suggestion would
have on emissions was performed. Even if 10 percent of the tanks equipped
with primary and secondary seals experienced total failure of one seal,
average emissions would be 4 percent lower than if all tanks had been
equipped with a primary seal only.
Comment: Three commenters (IV-D-9, IV-D-15, IV-D-17) discussed a
potential safety hazard in conducting an annual visual inspection in all
IFR's. Two commenters (IV-D-15, IV-D-17) suggested as an alternative to
the inspection requirement that VOC emissions be monitored annually from a
small fitting on the roof. They said that if monitoring indicates a
significant increase in emissions, an internal inspection would be
warranted to find and correct the problem. One commenter (IV-D-17)
suggested that this alternative replace the annual visual inspection while
the other commenter (IV-D-15) suggested that it be considered equivalent
to the visual inspection. Another commenter (IV-D-12) recommended that,
where safety problems can be caused by the requirements of an annual
visual inspection, visual inspection should be required when degassing
occurs or at intervals not greater than 10 years.
Response; The Agency agrees that in particular tanks, the annual
visual inspection may pose a problem. Therefore, as noted in the previous
response, the requirement has been altered. Because tanks in the chemical
industry are typically cleaned and degassed once every 5 years under
current practices, the revised requirements will alleviate any safety
problem with the annual visual inspection.
The alternative suggested by the commenters has not been incorporated
into the final standards. There are no data on which to select a hydro-
carbon concentration that would indicate a problem with the control
equipment. The hydrocarbon concentration measured at the roof fitting
would be heavily dependent upon recent tank operations (e.g., filling,
emptying, or static level) and liquid level. The Agency is not aware of
any method by which an annual concentration measurement could be used to
establish the condition of the control equipment.
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Comment; One commenter (IV-D-9) said that the time (1 hour)
estimated for the annual inspection is greatly underestimated, the
commenter requested a reference for the estimate. ;
Response; Based on site visits by EPA personnel, the Agency
determined that 1 hour is a reasonable estimate for the time required to
conduct an annual visual inspection; therefore, the costs based on the
time estimate will not be changed. Personnel from the Texas Air Control
Board said that the inspection takes 4 hours, which includes time for a
file search and time for writing the report. However, even using the
4-hour estimate, the cost of the annual inspection is not burdensome.
2.3.3.2 Ten-Year Inspection.
Comment; Three commenters (IV-D-7, IV-D-20, IV-D-39) said that the
requirement that IFR's be emptied and degassed at least once every
10 years is unreasonable for facilities with only one IFR or where
acceptable alternate tankage is not available. One commenter (IV-D-7)
requested that pipeline tank stations with only one IFR be exempt from
these requirements or that an operationally compatible method to empty and
degas the tanks be allowed.
Response; As stated in the previous response, tanks in the chemical
industry are typically emptied, degassed, and cleaned every 5 years.
Benzene storage vessels are typically emptied, degassed, and cleaned on
10-year intervals. The Agency has determined that it is typical industry-
practice to clean tanks on a regular basis and that the 10-year internal
inspection requirement is not an undue burden. The Agency has determined
that no special provisions are necessary for pipeline tanks. In many
instances, alternate tankage such as an EFR will likely be available. In
any case, it is not unreasonable to require a facility with only one IFR
to conduct a planned, internal inspection every 10 years. Further
discussion with one of the commenters (IV-D-7) revealed that existing
2"t
tanks were of concern. This NSPS will not affect existing storage
vessels; therefore, no changes have been made as a result of these
comments.
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2.3.4 Procedures for Vessels Found to be Out of Compliance
Comment: Several commenters said that the 30-day allowance for.
repairing or emptying storage vessels found to be out of compliance is
unreasonable. Two commenters (IV-D-20, IV-D-39) said that the provision
would necessitate the installation of two small tanks rather than a single
large tank to provide the flexibility to transfer material from a vessel
in need of repair. One commenter (IV-D-39) noted that the 30-day allow-
ance would be a problem at facilities with only four or five .tanks because
alternate tankage might not be available. Another commenter (IV-D-5)
noted that the provision would be a problem in the event a facility found
that several vessels were simultaneously out of compliance. One commenter
(IV-D-19) suggested that a 45-day allowance would give the operator
sufficient time to order, receive, and install new equipment without
having to request an extension. Four other commenters (IV-D-6, IV-D-7,
IV-0-12, IV-D-20) suggested a 90-day allowance as a reasonable time to
repair a vessel or remove it from service. One commenter (IV-D-39)
proposed a 120-day allowance.
Response-;. Discussion with storage vessel manufacturers indicated
that a 30-day allowance for repairing storage vessels in conjunction with
the option of requesting a 30-day extension is reasonable from the
supplier's viewpoint. However, in the.event that special materials not
normally kept in stock (such as Teflon® seals) were required, this time
would probably be insufficient.25'26 The Agency has decided to revise the
proposed standards to provide a 45-day allowance to accommodate delays in
repairing or emptying the storage vessel. A 30-day extension may still be
requested if repairs are likely to exceed the initial allowance.
2.3.5 Notification of Refill
Comment: Three commenters (IV-D-19, IV-D-23, IV-D-39) said that the
requirement to notify EPA 30 days prior to refilling storage vessels after
conducting a planned inspection is unnecessary and may delay the refilling
of needed storage capacity. Two commenters (IV-0-19, IV-D-39) said that
inspection prior to refilling should be a recordkeeping function. Another
commenter (IV-D-5) stated that the intent of the requirement was to
provide 30 days' notice to EPA prior to refilling the vessels. Two
commenters (IV-D-5, IV-D-23) suggested that the 30-day notification period
begin prior to the inspection.
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Response: The requirement is intended to provide 30 days' notice to
EPA prior to refilling the vessels and not to delay the start of the
notification period until after the vessel has been emptied. The
requirement has been revised to allow the notification period to begin
prior to emptying and inspecting the storage vessel.
Comment: Two commenters (IV-D-22, IV-D-23) discussed the 7-day
notification period in the event of an unplanned inspection. One
commenter (IV-D-22) said there would be the possibility of excessive
downtime and recommended that this requirement be deleted. If it is
retained, the commenter suggested a 2- to 3-day notification period. The
commenter also said that EPA should be required to provide a telephone
contact on weekends and holidays to enable the period to begin at any
time. The other commenter (IV-D-23) noted the possible delay in'returning
to normal operation resulting from the 7-day requirement and suggested
shortening the notification period to 8 business hours in the event of an
unplanned inspection.
Response; The Agency has determined that a 7-day notification period
in the event of an unplanned inspection is reasonable. - Discussions with a
representative of a tank service-company revealed that it takes from
2 days to 2 weeks to empty, degas, clean, and inspect a tank. Factors
such as increasing tank size, heavy sludge deposits, worker and equipment
access to the tanks, and the need to replace seals can all increase the
length of time needed beyond the minimum to perform the work. The ability
of the service company to respond rapidly to an emergency call depends on
the availability of workers and equipment. Therefore, the Agency has
decided that a 7-day notification period will not result in excessive
downtime throughout the industry. Furthermore, the 7-day period is
necessary from the Agency's perspective to allow adequate time for the
mobilization of the necessary manpower and resources to inspect the
vessel. For example, 2 to 3 days are often required to receive approval
for travel, and additional time is required to make travel arrangements.
Inspections are often coordinated with State and local agency personnel,
and time is required to coordinate schedules. In the event the
owner/operator makes the Agency aware of a special problem on a vessel
requiring immediate refill, the Agency will make every effort to respond
as quickly as possible.
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2.4 MODIFICATION
Comment: Six commenters (IV-D-2, IV-D-13, IV-D-18, IV-D-22, IV-D-23,
IV-0-39) requested clarification of the modification provision. The
commenters suggested excluding the changing of liquids in storage vessels
from constituting a modification if the existing facility was originally
designed to accommodate the alternate liquids. Three commenters (IV-D-18,
IV-D-22, IV-0-39) suggested that this be accomplished by exempting as
affected facilities vessels meeting these conditions. One commenter
(IV-D-13) suggested the proposed standards clearly state that little can
be done to a storage vessel to qualify as a modification.
Response: The commenters are correct that a change of the stored
liquid in and of itself will not be a modification to an existing
vessel. If a vessel constructed prior to July 23, 1984 (date of proposal
of these standards), were storing a non-VOL or a VOL with a vapor pressure
below the cutoffs (5.2 kPa [0.75 psia] for tanks with capacities greater
than 151 m [40,000 gal] and 27.6 kPa [4 psia] for tanks with capacities
equal to or greater than 75 m3 [20,000 gal] but less than 151 m3
[40,000 gal]) and the vessel contents were changed to an affected VOL, the
vessel would not be considered an affected facility under Subpart Kb if
the existing facility had been designed to accommodate the new liquid.
However, if a vessel constructed after proposal undergoes a similar
change, the vessel could fall under the control requirement provisions of
Subpart Kb. Because this distinction is clear in § 60.14 of the General
Provisions, no changes are incorporated into the final rule.
Comment; One commenter (IV-D-22) suggested that vessels that suffer
from catastrophic failure should be exempt from the proposed standards if
they are reconstructed "in-kind" and preexisting controls achieved at
least an 85 percent emission reduction. The commenter also stated that
existing vessels that are modified should be exempt if they are operated
with controls that are at least 85 percent efficient.
Response; The provisions for modification and reconstruction are
clearly defined by §§ 60.14 and 60.15 of the General Provisions. They do
not allow "in-kind" reconstruction or modification, even in the event of a
catastrophic failure. The intent of Section 111 of the Clean Air Act is
to reduce emissions as older facilities are modified or replaced with new
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facilities by requiring that the modified or new facilities meet i the
NSPS. In the case of facilities that are not completely new, the Agency
has made provisions that reconstructed facilities will also be required to
meet the NSPS. An allowance for "in-kind" replacement would be
inconsistent with the Act's intent. Additionally, the cost effectiveness
of controls for a modified or reconstructed facility would be comparable
to that of a new facility. This cost effectiveness is reasonable (a net
credit on average). Therefore, the proposed standards have not been
revised as the commenter suggests.
2.5 COST EFFECTIVENESS
2.5.1 Capital Recovery Factor
Comment: One commenter (IV-D-8) stated that the capital recovery
factors used in the cost analysis are not representative of the ones
used in the petroleum industry. According to the commenter, the analysis
should have been based on "equity financing" rather than "debt financing."
The commenter said that the use of equity financing would double the
capital recovery factors and increase the costs of the control options.
Response: Capital recovery factors for regulatory cost and'
cost-effectiveness analyses are traditionally based'upon a 10-percent real
interest rate and the physical lifetimes of control equipment. Such
estimates are intended to reflect the cost of regulation to society.
As noted in Chapter 9 of the Volume I BID, industry financial
characteristics were considered in the economic impact analysis through
the calculation of an industry-specific cost of capital, which incorpo-
rates all types of financing. This cost of capital estimate is an average
of the costs of debt, equity, and preferred stock, weighted by the
percentage of funds generated by each type of financing. The cost of
capital estimate was based on a sample of 100 firms, some of which were
petroleum companies. The cost of capital estimate reflects the types of
financing employed by both firms that operate primarily in the'chemical
industry and firms that operate primarily in the petroleum industry.
2.5.2 Product Recovery
Comment: Three commenters questioned the product recovery credits
used in the analysis. One commenter (IV-D-8) said that the assumed
product value is about double the product value commonly assumed in the
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petroleum industry. The commenter concluded that the economic analysis
overstates the credit for product recovery and makes the cost-effective-
ness values for controls on the petroleum industry appear more attractive
than they really are.
Another commenter (IV-D-15) requested that the choice of product
recovery values be clarified. The commenter noted that values of $360/Mg
($400/ton) and $695/Mg ($770/ton) were noted in the preamble to the
proposed standards while values of $460/Mg ($510/ton) were used in the
Volume I BID.
A third commenter (IV-D-18) said that no product recovery credit is
available to the "for-hire" terminals.
Response: The Agency reexamined the cost-effectiveness values for
controls on petroleum liquid storage vessels. A lower product value,
$220/Mg, was assumed. Based on information developed for the draft
Control Techniques Guideline document, this product value is reasonable.
The cost effectiveness of a typical petroleum liquid storage vessel (30 m3
[100 ft] in diameter) was calculated for a low vapor pressure crude oil
and for a higher vapor pressure gasoline.1 Assuming 12 turnovers per year
on the crude vessel, the cost effectiveness is $824/Mg., The cost effec-
tiveness on the gasoline storage vessel .is $l,149/Mg at 12 turnovers per
year. The cost effectiveness of control of these vessels is considered
reasonable even when a lower product value is assumed.
The product values in the preamble reflect a worst-case cost
($360/Mg) for chemicals and an average price ($695/Mg) of chemicals
between 3.5 and 10.4 kPa (0.5 and 1.5 psia), respectively. These prices
were used to set the control cutoffs ($360/Mg) and to evaluate the impacts
of the standards on a typical tank storing a low pressure liquid
($695/Mg). The value in the Volume I BID ($460/Mg) represents a nation-
wide average of retail prices of high volume chemicals and was used to
evaluate the overall impacts of the standards on the chemical industry.
All product recovery credits are expressed in 1982 dollars.
While a direct product recovery credit is not available at-"for hire"
terminals, an indirect credit is available because less product is lost as
the result of emission controls, and the company can reasonably charge
more for storage in the tanks that have fewer losses.
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Comment: One commenter (IV-D-15) stated that the cost calculations
show that as larger vessels are considered, the product recovery credit
becomes greater than the cost of control. The commenter questioned
whether the proposed standards are necessary in this case.
Response: In some cases, the cost of controlling VOC emissions
yields a net credit because of the value of the recovered product, and, in
such cases, industry may adopt the control independent of any regula-
tion. However, there is no assurance or experience to show that this will
occur. There are other cases where control of storage vessels, While cost
effective, has a net cost to the owner. In these cases, in the absence of
an NSPS, BDT would probably not be installed by the facility. In
addition, it may be possible to install control technology that would
yield a net credit to the owner but would not be as efficient as BDT.
This would occur where the overall cost is a credit and where there is an
incremental cost between the differing levels of control. In such
situations, an NSPS is necessary to ensure that BDT is installed in all
cases. Even when the BDT is installed, the NSPS ensures proper operation
and maintenance, of the equipment and, thus, the maximum emission reduc-
tion. For these-reasons and in-order to implement uniform, nationwide
standards, the Agency has decided to apply the NSPS to all affected
facilities.
2.5.3 Cost of Controls (Cost Effectiveness)
2.5.3.1 Add-On Controls.
Comment: One commenter (IV-D-2) stated that control of a 151-m
(40,000-gal) vessel storing liquid with a vapor pressure of 3.5 kPa
(0.51 psia) would have an unreasonable cost effectiveness of at least
$8,800/Mg if the VOC's were ducted to an existing control device. The
commenter noted that if the costs of a new control device were considered,
the cost-effectiveness value would likely be an order of magnitude
higher. Another commenter (IV-D-5) said that no consideration was given
to the incremental cost of utilizing carbon adsorption, incineration, or
other similar control devices when considering individual vessels.
Response: As discussed earlier, the vapor pressure cutoff has been
changed from 3.5 to 5.2 kPa (0.51 to 0.75 psia). In any case, the
owner/operator does not have to install a closed vent system and control
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device. Internal floating roofs can be built at a reasonable cost and are
applicable to a wide variety of storage situations. These are the reasons
this technology was selected as BOT. For example, the cost effectiveness
of using an internal floating roof to control the tank described by the
commenter (151 m3 [40,000 gal] in capacity and storing a liquid with a
vapor pressure of 3.5 kPa [0.51 psia]) is $l,940/Mg, assuming
50 turnovers/year and a product value of $460/Mg. The cost of controlling
the same tank storing liquid with a vapor pressure of 5.2 kPa (0.75 psia)
and a lower product value ($360/Mg) is only $l,290/Mg.27 However, these
standards allow the owner or operator to control emissions with a closed
vent system and control device that is 95 percent efficient because these
controls achieve the same emission reduction as BOT. As noted in previous
responses, these systems are also widely used and achieve a reasonable
cost effectiveness for small tanks storing high pressure liquids or on a
plant-wide basis.
2.5.3.2 Floating Roof Vessels.
Comment: One commenter (IV-0-7) questioned the assumption that
controlled fittings costs are negligible.
Response: The. Agency agrees that the cost of- the control
requirements for fittings is greater than zero but still maintains that it
is small in comparison to the overall cost of the IFR. Estimates from
vendors indicate that controlled fittings increase the installed capital
cost of the IFR between 1 and 4 percent.18 In a 10-m3 (33-ft) diameter
tank, this is about $500 if controlled fittings increase the cost by
4 percent.
Previous responses have discussed the cost effectiveness of
controlling fittings and have demonstrated that the cost effectiveness of
the revised requirements is reasonable.
Comment; One commenter (IV-D-8) stated that the estimated costs for
IFR's are understated. The commenter compared his estimate of $40,000 to
install an internal floating roof in a 15-m3 (49-ft) diameter vessel to
the $17,120 assumed in the analysis. The commenter requested that all
factors and assumptions used in estimating installed costs be stated.
Another commenter (IV-D-7) requested that EPA reevaluate the
cost-effectiveness values for IFR's and EFR's and any regulatory decisions
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resulting from them. The commenter's estimates for these values were
significantly higher than those made by EPA. The commenter also said that
it was not possible to replicate EPA's estimates using the information
supplied on estimated installed capital costs of IFR's.
Response: Although the commenter did not provide all of the
assumptions used in his cost estimate, it is likely that the $40,000
estimate is based on welded steel deck. As Table 2-8 shows, the
commenter's estimate is comparable to the installed costs of welded steel
decks that were developed in the Volume I BID. With one exception, the
Agency believes that the costs presented in the Volume I BID are
reasonable and accurate estimates of the costs to control tanks. ' Two
comments received on the draft CTG stated that the costs used in that
document accurately reflected the commenters1 actual experience in
retrofitting tanks. The costs used in the CTG were developed from the
costs presented in Chapter 8 of the Volume I BID. The primary assumption
used in the costs is that the vessel is empty, clean, and otherwise ready
for the IFR.
One change that has been made in the costs since proposal is in
regard to the cost and lifetime of equipping a noncontact deck with a
liquid-mounted primary seal. Information received in responses to the CTG
indicates that the $2.60/linear meter seal cost had been underestimated.
Also, the lifetime of this seal system has been revised downward [from
20 years to 10 years. However, the cost effectiveness of BDT is still
reasonable. The cost effectiveness of controls will range from about
$515/Mg (assuming the product has no value) to net credits (if the product
value exceeds $515/Mg) for a model tank with the following parameters :
1. Volume=606 m3 (160,000 gal);
2. Diameter=9.1 m (30 ft);
3. Vapor pressure=6.9 kPa (1 psia);
4. Molecular weight=80 Ib/lb mole; and
5. Turnover rate=50 per year.
These values are reasonable, and no changes have been made to the controls
required by § 60.112b as a result of these changes in costs.
The estimates for the emission reduction obtained by fittings should
have been 0.894 Mg/yr and not the 0.1 Mg/yr presented in the Volume I
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TABLE 2-8. ESTIMATED INSTALLED COST OF A WELDED CONTACT INTERNAL
FLOATING ROOF WITH SECONDARY SEAL
(Fourth quarter 1982 dollars)
Tank
diameter, m
5
10
15
20
25
30
Roof
cost, $a
15,900
30,000
44,000
58,100
. • ' 72,100
86,100
aThe basic cost of the roof and primary seal is
estimated from the equation: cost ($1,000) =
1.91 + 2.54D; Where D equals the tank diameter in
meters with the correlation coefficient r = 0.883.
The additional cost of a secondary seal is estimated
based on the factor of $85 per linear meter of
circumference. The secondary seal cost is the
average price of 13 seals from 8 different vendors.
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BID. The cost effectiveness of the revised fitting requirements is
presented in Section 2.2.4 of this document.
Comment; One commenter (IV-0-15) said that the costs of lined tanks
or pad systems, which are required on many SOCMI tanks, are not rfepre-
sented by the cost estimates, which are based on general tanks holding
petroleum liquids. !
Response; The cost of tank liners or pad systems for a tank do not
affect the costs of controls. These costs are part of the tank, and the
tank would be so equipped both with and without the controls. Therefore,
these costs are part of both the controlled and uncontrolled case and do
not affect the incremental costs of control.
2.6 MISCELLANEOUS
Comment; Two commenters (IV-D-17, IV-D-39) said that it may be
difficult for an operator to determine whether or not a vessel is covered
by the standards and, if so, what provisions are applicable. The com-
menters recommended that EPA redraft the proposed standards but provided
no specific examples of how to do so. Another commenter (IV-D-5): recom-.
mended that EPA.supplement the text on these standards with a table
summarizing the control requirements by tank size and vapor pressure. The
commenter said that this would avoid potential confusion in determining
applicability of the standards.
Response; The Agency has determined that the format for determining
applicability in the proposed" standards is adequate, and no changes have
been made to the final standards. Any storage vessel owner/operator with
specific questions regarding applicability may contact EPA or the
permitting authority.
Comment; Two commenters (IV-D-7, IV-D-8) said that EPA's analysis in
the BID is based solely on tanks in the chemical industry and does not
reflect tank populations, VOC properties and costs, equipment costs, or
control cost effectiveness associated with petroleum liquids.
Response; As stated in several previous responses in this document,
the Agency has determined that controlling emissions from petroleum liquid
storage vessels is cost effective.
The costs presented in Chapter 8 of the Volume I BID reflect the
costs of controls for petroleum liquid storage vessels. Tank population
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and. the emission reduction obtained by the regulatory alternatives are
presented in Appendix D of the Volume I BID. Therefore, it is concluded
that BOT is appropriate for petroleum liquid storage vessels, and no
changes have been made to the final standards as a result of this comment.
Comment; One commenter (IV-D-15) said that actual emissions from
fixed roof storage tanks in the chemical industry, especially padded ones,
are overestimated by the emission equations.
Response: In further discussions, the commenter contended that
blanketing fixed roof tanks will reduce breathing losses by creating a VOC
concentration gradient within the vapor space. The gradient would be
created because fresh blanketing gas is drawn from a line at the top of
the tank. Thus, the gas expelled during breathing would consist mainly of
blanketing gas. The commenter also contended that the same principle will
slightly reduce fixed roof tank working losses.28
The situation described by the commenter does not differ from
unblanketed fixed roof tanks. Such tanks draw fresh air through a vent in
the top of the tank and expel a VOC/air mixture later. The current
breathing loss equations do not assume saturation of the vapor space
inside the tank, thereby allowing for the VOC concentration gradient
described by the commenter. Therefore, the Agency believes that the
emission equations used in the BIO adequately account for the case
described by the commenter.
Even if the commenter is correct and blanketing reduces fixed roof
tank breathing losses, the losses account for only about 14 percent of
total losses for a typical fixed roof tank in the chemical industry.
Therefore, even in the most extreme case, the theoretical situation
described by the commenter would not affect the selection of BDT for these
tanks.
Comment: One commenter (IV-D-4) suggested that numbers be rounded in
the proposed standards. Three commenters (IV-0-5, IV-D-9, IV-D-39)
requested that English unit equivalents be shown in parentheses in the
proposed standards.
Response; Numbers have been rounded in the final standards where
appropriate. However, in cases where rounding would undermine historical
precedents for control cutoffs, values have been retained as written.
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English unit equivalents have been included for the industry's convenience
in the Preamble to the final standards. English unit equivalents have not
been added to the regulation, however. Such a revision, because of
conversion factors, would modify the control cutoffs and, in some cases,
would make the cutoffs more stringent than those originally proposed.
This would result in the need to repropose cutoffs and would be
counterproductive to a timely promulgation of the standards.
Comment: One commenter (IV-D-7) noted a typographical error in
§ 60.111b(f). The commenter said that "nonvolatile" should be changed to
"volatile." j
Response; The commenter was correct in noting a typographical error
in what was originally § 60.111b(f). The correction has been made in the
final standards. This section is now §60.111b(g).
Comment; One commenter (IV-D-7) requested that the proposed
standards include definitions that are found in the preamble for terms
such as "VOC" and "petroleum liquid."
Response; The term "VOC" has been defined in § 60.2 of the General
Provisions of the Clean Air Act. However, the term "petroleum liquids"
has been defined in the final standards in § 60.111b(i).
Comment; One commenter (IV-D-7) suggested that floating roof
fittings be defined per page 22 of API Bulletin No. 2519. The commenter
said that this will avoid inconsistency with API Bulletin No. 2519 and
recognize that an automatic bleeder vent is the same as a vacuum
breaker.
Response; The commenter was correct in noting inconsistency in the
floating roof fitting definition. The Agency recognizes that automatic
bleeder vents are the same as vacuum breaker vents, and the correction has
been made in the final standards.
Comment; One commenter (IV-D-7) had the following comments on
§ 60.112b(a)(l) and (2):
1. The section should distinguish between contact and noncontact
roofs. The commenter also said that deck penetration on contact ;roofs in
IFR's and EFR's should not extend into the liquid as is required in these
sections for all floating decks regardless of type.
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2. The wording "except for contact decks" should be added to
§ 60.ll2b(a)(l)(111.) to make §§ 60.112b(a)(l) and (2) consistent .
throughout.
3. The'wording "column wells" should be deleted in
§ 60.112b(a)(l)(iv) and "leg sleeves" should be added for completeness.
4. Section 60.112b(a)(l)(v) should be revised to read ". . . at all
times when the roof is floating, except when the roof is being floated off
or landed on the roof by supports. ..." for correctness and consistency
with proposed § 60.112b(a)(2)(ii).
5. The word "form" should be changed to "foam" in the fourth line of
§ 60.112b(a)(2)(i)(A).
Response; The requirement that deck penetrations on contact decks
extend to the liquid has been deleted. The Agency recognizes that this
requirement is not necessary because there is no vapor space under the
deck, and all related changes have been made in the final standards. The
relevant typographical errors noted by the commenter have been changed in
the final standards.
Comment: One commenter (IV-D-13) said that if there is no reason not
to allow the use of control options defined in §§ 60.112b(a)(l), (2), and
(3) for tanks storing high vapor pressure liquids defined in § 60.112(b),
§ 60.112b(a) can be rewritten as follows:
"The owner or operator of each storage vessel with a design capacity
greater than or equal to 151 m3 containing VOL that, as stored, has a
maximum true vapor pressure equal to or greater than 3.5 kPa or a design
capacity greater than or equal to 75 m3 but less than 151 m3 containing
VOL that, as stored, has a maximum true vapor pressure equal to or greater
than 27.5 kPa, shall equip each storage vessel with one of the
following . . ." and § 60.112b(b) can then be deleted.
Response: The modification suggested by the commenter is not
equivalent in meaning to the original language. The suggested wording
would delete the control requirement for pressure vessels equipped with
closed vent systems and for control devices storing high vapor pressure
liquids (76.6 kPa [11.1 psia] or greater). Therefore, the Agency has not
revised the standards according to the commenter's suggestion.
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Comment: One commenter (IV-D-4) suggested that "external floating
roof" be defined in § 60.111b rather than in § 60.112b(a)(2).
Response; The definitions in § GO.lllb are general in nature and
apply to the subpart as a whole. The term "external floating roof" is
best described in the section (§ 60.112b(a)(2)) describing control
techniques, and no changes have been made in the final standards.
Comment; One commenter (IV-D-7) made several minor editorial
comments on the Volume I BID.
Response; None of the changes suggested by the commenter wifll have
any impact on the selection or form of the final standards. Therefore,
the Volume I BID is considered a final document, and no changes have been
made.
Comment: One commenter (IV-D-39) stated that the standards are
unfair to the owner or operator of a new vessel constructed after the date
of proposal but prior to the date of promulgation.
Response; In passing the Clean Air Act, Congress gave as one of the
purposes of the Act the protection and enhancement of the "quality of the
Nation's air resources so as to promote the public health and welfare and
the productive capacity of its population" (Section 101(b)(2)).
Therefore, in order to provide the maximum benefit from the regulations,
the Congress provided that the date regulations are proposed is the date
they become applicable to new sources (Section lll(a)(2)).
2.7 REFERENCES FOR CHAPTER 2 '
1. Memo from Friedman, E. M., Midwest Research Institute, to VOL Project
File. June 28, 1985. Cost effectiveness of BDT tanks.
2. IT Enviroscience, Inc. Organic Chemical Manufacturing Volume 3:
Storage, Fugitive, and Secondary Sources. Prepared for U. S;.
Environmental Protection Agency. Research Triangle Park, NC.
Publication No. EPA-450/3-80-025. December 1980. pp. II-6 to
11-11.
3. Memo from Friedman, E. M., Midwest Research Institute, to VOL Project
File. September 5, 1985. Impact of diurnal temperature change on
cost effectiveness.
4. Telecon. Moody, W. T., Midwest Research Institute, with Forbes, R.,
Eastman Kodak, Inc. November 20, 1984. Clarification of comments on
underground storage tanks. :
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5. Factory Mutual Engineering Corp. Storage Tanks for Flammable and
Combustible Liquids. 7-88. July 1976.
6. Memo from Taylor, D., Midwest Research Institute, to VOL Project
File. January 3, 1985. Cost effectiveness of condensing systems for
underground storage tanks.
7. Telecon. Moody, W. T., Midwest Research Institute, with Skaggs, M.,
Diamond Shamrock, Inc. November 21, 1984. Clarification of comments
and discussion of technical issues.
8. Telecon. Moody, W. T., Midwest Research Institute, with
Crowther, S., Texas Air Control Board. November 26, 1984. Industry
use of horizontal storage tanks.
9. Memo from Friedman, E. M., Midwest Research Institute, to Butler, L.,
EPA. November 20, 1984. Cost effectiveness of BOT for chlorinated
liquids.
10. Memo from Taylor, D., Midwest Research Institute, to VOL Project
File. February 22, 1985. Calculations used for condenser cost
effectiveness.
11. Letter from Rockstroh, M., TRW, Incorporated, to Smith, V., Research
Triangle Institute. July 10, 1980. Distribution of VOL storage tank
population.
12. Telecon. Friedman E. M., Midwest Research Institute, with
Potter, S., Gray Laboratories. December 28, 1984. Laboratory fee
for Re-id vapor pressure determination.
13i, Memo from Friedman, E. M., Midwest Research Institute, to VOL Project
File. September 5, 1985. Storage of heavy, waxy crudes.
14. Telecon. Friedman, E. M., Midwest Research Institute, with
Nickolaus, A., E. I. du Pont de Nemours & Company, Inc. May 17,
1985. Distribution of constant level tanks.
15. Telecon. Friedman, E. M., Midwest Research Institute, with Roy, A.,
Allied Corporation. May 24, 1985. Distribution of constant level
tanks.
16. Memo from Taylor, 0., Midwest Research Institute, to VOL Project
File. December 31, 1984. Cost-effectiveness calculations for
comparing fixed roof tanks to internal floating roof tanks.
17. Memo from Friedman, E. M., Midwest Research Institute, to VOL Project
File. December 31, 1986. Revised cost-effectiveness calculations
for comparing fixed roof tanks to internal floating roof tanks.
18. Research Triangle Institute. Petroleum Liquid Storage Tank NSPS:
Economic Impacts on Bulk Gasoline Plants. May 1985. 19 p.
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19. Telecon. Moody, W. T., Midwest Research Institute, with Kern, R.,
Ultrafloate. November 26, 1984. Operation of internal floating roof
tanks.
20. Telecon. Taylor, D., Midwest Research Institute, with Cooke, A.,
Southern Pump and Tank Company. December 13, 1984. Fiberglass
storage vessels.
21. Telecon. Moody, W. T., Midwest Research Institute, with
Nickolaus, A., E. I. du Pont de Nemours & Company, Inc. November 28,
1984. Clarification of comments.
22. Memo from Friedman, E. M., Midwest Research Institute, to VOL Project
File. September 5, 1985. Column fittings.
23. Telecon. Friedman, E. M., Midwest Research Institute, with
Peters, M., Texas Air Control Board. November 26 and 27, 1984.
Annual inspection requirements.
24. Telecon. McDonald, R., U. S. Environmental Protection Agency, with
Walter, J., American Petroleum Institute. December 5, 1984. Ten-
year inspection requirements.
25. Telecon. Taylor, D., Midwest Research Institute, with 01 sen, K.,
High Rise Services Corp. December 13, 1984. Inspection procedures
for storage vessels.
26. Telecon. Friedman, E. M., Midwest Research .Institute, with
Ferry, R., Conservatek, Inc. December 11, 1984. Supply constraints
for storage vessel repairs.
27. Memo from Friedman, E. M., Midwest Research Institute, to VOL Project
File. December 31, 1986. Revised cost-effectiveness calculations
for BDT tanks.
28. Telecon. Friedman, E. M., Midwest Research Institute, with
Lingafelter, T. E., Dow Chemical U.S.A. February 14, 1985.
Emissions from padded tanks.
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before comp/eting/
REPORT NO.
EPA-450/3-81-003b
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
VOC Emissions from Volatile Organic Liquid Storage
Tanks - Background Information for Promulgated
Standards of Performance
5. REPORT DATE
January 1987
6. PERFORMING ORGANIZATION CODE
. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
10. PROGRAM ELEMENT NO.
Office of Air Quality Planning and Standards
Environmental Protection Agency
Research Triangle Park, North Carolina 27711
11. CONTRACT/GRANT NO.
68-02-3063
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
DAA for Air Quality Planning and Standards
Office of Air, Noise, and Radiation
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
14. SPONSORING AGENCY CODE
EPA/200/04
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Standards of Performance for the control of VOC emissions from Volatile Organic
Liquid (VOL) storage tanks are being promulgated under the authority of
Section 111 of the Clean Air Act. These standards would apply to all new and
existing storage tanks having a capacity of 75 cubic meters or larger, which
are to be used for the storage of VOL. This.document contains a summary of the
public comments on the proposed revised standards and the EPA's responses, as
well as sunmary economic and environmental impact statements.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Air pollution Bulk Liquid Terminals
Pollution control Equipment standard
Storage tanks Standards of Performance
Contact floating roofs
Chemical Manufacturing Plants
Volatile Organic Compounds
Volatile Organic Liquids
Air Pollution Control
13 B
18. DISTRIBUTION STATEMENT
19. SECURITY CLASS (This Report/
Unclassified
21. NO. OF PAGES
77
Unlimited
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
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