[Federal Register: July 21, 2009 (Volume 74, Number 138)]
[Rules and Regulations]
[Page 35789-35792]
[DOCID:fr21jy09-10]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-28988; Directorate Identifier 2007-NM-047-AD;
Amendment 39-15975; AD 2009-15-12]
RIN 2120-AA64

Airworthiness Directives; Boeing Model 747-400 and -400D Series
Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for certain
Boeing Model 747-400 and -400D series airplanes. This AD requires
installing new relays to allow the flightcrew to turn off electrical
power to the in-flight entertainment (IFE) system and other non-
essential passenger cabin systems through the left and right utility
bus switches, and other specified actions. This AD results from an IFE
systems review. We are issuing this AD to ensure that the flightcrew is
able to turn off electrical power to the IFE system and other non-
essential passenger cabin systems through utility bus switches in the
flight compartment, in the event of smoke or fumes. The flightcrew's
inability to turn off electrical power to the IFE system and other non-
essential passenger cabin systems could result in the inability to
control smoke or fumes in the airplane flight deck or passenger cabin
during a non-normal or emergency situation.

DATES: This AD is effective August 25, 2009.
    The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of August 25,
2009.

ADDRESSES: For service information identified in this AD, contact
Boeing Commercial Airplanes, Attention: Data & Services Management,
P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-
544-5000, extension 1; fax<PHONE_NUMBER>; e-mail<EMAIL_ADDRESS>
Internet https://www.myboeingfleet.com.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://
www.regulations.gov; or in person at the Docket Management Facility
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The AD docket contains this AD, the regulatory evaluation,
any comments received, and other information. The address for the
Docket Office (telephone<PHONE_NUMBER>) is the Document Management
Facility, U.S. Department of Transportation, Docket Operations, M-30,
West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE.,
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Joe Salameh, Aerospace Engineer,
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-
3356; telephone<PHONE_NUMBER>; fax<PHONE_NUMBER>.

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 to include an airworthiness directive (AD) that would apply to
certain Boeing Model 747-400 and -400D series airplanes. That NPRM was
published in the Federal Register on August 16, 2007 (72 FR 45968).
That NPRM proposed to require installing new relays to allow the
flightcrew to turn off electrical power to the in-flight entertainment
(IFE) system and other non-essential passenger cabin systems through
the left and right utility bus switches, and other specified actions.

Comments

    We gave the public the opportunity to participate in developing
this AD. We considered the comments received from the three commenters.

Support for the NPRM

    Inflight Canada (IFC) strongly supports the intent of the NPRM.

Request To Clarify Service Bulletin Instructions

    Boeing requests that we clarify, in the ``Relevant Service
Information'' section of the NPRM, that Boeing Service Bulletin 747-24-
2246, dated October 6, 2005, provides procedures for turning off 28 VDC
power to the IFE system. Boeing states that all Model 747-400 series
airplanes have 115 VAC control, and that representing the proposed
actions as addressing electrical power, in general, might be misleading
to operators regarding the scope of the action.
    We agree to provide clarification. We understand that operators are
able to turn off 115 VAC power under the existing configuration for
Model 747 series airplanes, and that Boeing Service Bulletin 747-24-
2246, dated October 6, 2005, provides changes to also allow for turning
off 28 VDC power. Therefore, the wording of the NPRM is appropriate and
not misleading, since the intent of this AD is to ensure that all
electrical power is removed from the affected systems through the use
of the right and left utility bus switches. No change to the AD is
necessary in this regard.

Request To Clarify Instructions for Airplanes Modified After Delivery

    Boeing requests that we clarify, in the ``Relevant Service
Information'' section of the NPRM, that instructions in Boeing service
bulletins are based upon the delivered product configuration. Boeing
states that it is not obvious to operators that post-production
modifications to the IFE system might require an alternative method of
compliance (AMOC) to comply with the requirements of the AD.
    We agree that operators might not be able to accomplish the
requirements of this AD on airplanes that have been modified or altered
after airplane delivery. Section 39.17 of the Federal Aviation
Regulations (14 CFR 39.17) specifically addresses this situation. If a
change in a product affects one's ability to accomplish the actions
required by an AD, then a request for FAA approval of an AMOC
addressing that configuration must be submitted in accordance with the
procedures specified in paragraph (g) of this AD. According to 14 CFR
39.17, the request should include the specific actions that are
proposed to address the unsafe condition, unless one can show that the
change eliminated the unsafe condition. No change to the AD is
necessary in this regard.

Request To Remove Certain Airplanes From the Applicability

    Lufthansa states that it has installed two additional Heath Techna
power distribution panels (P94 and P9100) on all of its affected
airplanes, in accordance with Supplemental Type Certificate (STC)
ST01507SE, issued February 11, 2005, amended September 7, 2006.
Lufthansa states that, on these modified airplanes, power can be turned
off by right and left utility bus switches located in the cockpit.
Lufthansa also states that, additionally, the cabin crew is able to
turn off power to the IFE and passenger seats using a master switch
located in the purser station of the cabin. Since the modification
addresses the intent of the NPRM, Lufthansa has asked Boeing to remove
all of Lufthansa's airplanes from the effectivity of Boeing Service
Bulletin 747-24-2246, dated October 6, 2005. We refer to that service
bulletin for the applicability of this AD.
    We infer that Lufthansa requests that we remove airplanes modified
in accordance with STC ST01507SE from the applicability of this AD. We
disagree with revising the applicability of this AD because we have
determined that, based upon the delivered airplane configuration, the
unsafe condition of this AD applies to the airplanes identified in the
effectivity of Boeing Service Bulletin 747-24-2246, dated October 6,
2005. STC ST01507SE, at the time of its issuance, was not evaluated as
an AMOC to the requirements of this AD. The design and installation
aspects of the STC must be reviewed under an AMOC request submitted by
either the STC applicant or the operator. Under the provisions of
paragraph (g) of this AD, we will consider requests for approval of an
AMOC if sufficient data are submitted to substantiate that the design
change would provide an acceptable level of safety. We have not changed
the AD in this regard.

Recommendation To Consider This AD an Interim Action

    IFC recommends that we consider the requirements of this AD an
interim action. IFC states the final action for eliminating the unsafe
condition should be to move the components and wire bundles from the
cabin area to areas where they will not be subjected to damage and
abuse. IFC states that the cabin sidewalls and the area under the cabin
floor offer much safer environments for these items.
    We disagree with considering this AD an interim action. The intent
of the AD is to address the unsafe condition, not to provide design
guidelines for installation of the IFE system. We have determined that
the requirements of this AD adequately address the unsafe condition.
Should new reports or data arise that show that the unsafe condition
has not been adequately addressed by the requirements of this AD, we
could consider further rulemaking. No change to the AD is necessary in
this regard.

Recommendation To Remove Power From All Components in the Cabin

    IFC recommends that the requirement to be able to remove power from
the IFE system be expanded to include all components using power in the
passenger cabin. IFC states that, in most cases, the In Seat Power
Systems (ISPS) and seat adjustment systems carry much

higher power loads than do the IFE components.
    We disagree that the scope of the AD needs to be expanded because
the ISPS and seat adjustment systems are addressed already as other
non-essential cabin systems in Boeing Service Bulletin 747-24-2246,
dated October 6, 2005. No change to the AD is necessary in this regard.

Recommendation To Locate Primary Switch in the Passenger Cabin

    IFC recommends that the primary switch to isolate the IFE system
and other non-essential cabin systems be located in the cabin, rather
than in the cockpit. IFC states that, in most cases, the cabin crew
will be the first to notice a problem, and that the additional time
needed to notify the flightcrew will allow the problem to worsen if not
immediately addressed by the trained cabin crew. IFC states that, if
desired, a secondary switch could also be located in the cockpit.
    We disagree because Boeing's design approach adequately addresses
the unsafe condition; the flightcrew can shut off power to any non-
essential system in the event of smoke or fire in the flight deck or
passenger cabin. However, under the provisions of paragraph (g) of this
AD, we will consider requests for approval of an AMOC if sufficient
data are submitted to substantiate that the design change would provide
an acceptable level of safety. We have not changed the AD in this
regard.

Recommendation to Automatically Turn Off Power in an Emergency

    IFC recommends that the system, which will provide the IFE shut-off
capability, also be required to automatically turn off power in the
event of certain emergencies, such as deployment of oxygen masks or
loss of a generator. IFC states that this capability would allow the
flightcrew and cabin crew to perform more important tasks without
having to be concerned with turning off power to the IFE system.
    We disagree with requiring the system to automatically turn off
power to the IFE system and other non-essential cabin systems in the
event of certain emergencies because, currently, there is no regulatory
requirement to have power turned off automatically. We are issuing this
AD to address a specific unsafe condition, and the areas discussed by
IFC fall outside the requirements of this AD. We have not changed the
AD in this regard.

Recommendation To Allow Operators To Develop Other Solutions

    IFC states that Boeing Service Bulletin 747-24-2246, dated October
6, 2005, which is referenced as the only acceptable means of complying
with the intent of the NPRM, provides only limited protection from the
myriad of electrical hazards in the cabin. IFC recommends that we
establish the desired functionality of a system for dealing with the
electrical hazards, and then allow operators to develop workable
solutions using these in combination with other designs to meet the
requirements.
    We disagree because we are issuing this AD to address a specific
unsafe condition, and we have determined that the service information
that is currently available adequately addresses that unsafe condition.
However, under the provisions of paragraph (g) of this AD, we will
consider requests for approval of an AMOC if sufficient data are
submitted to substantiate that the design change would provide an
acceptable level of safety. We have not changed the AD in this regard.

Conclusion

    We reviewed the relevant data, considered the comments received,
and determined that air safety and the public interest require adopting
the AD as proposed.

Costs of Compliance

    There are about 490 airplanes of the affected design in the
worldwide fleet. This AD affects about 62 airplanes of U.S. registry.
The required actions take about 123 work hours per airplane, at an
average labor rate of $80 per work hour. Required parts cost between
$9,412 and $11,936 per airplane. Based on these figures, the estimated
cost of the AD for U.S. operators is up to $1,350,112, or up to $21,776
per airplane.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, section 106, describes the
authority of the FAA Administrator. ``Subtitle VII: Aviation
Programs,'' describes in more detail the scope of the Agency's
authority.
    We are issuing this rulemaking under the authority described in
``Subtitle VII, Part A, Subpart III, Section 44701: General
requirements.'' Under that section, Congress charges the FAA with
promoting safe flight of civil aircraft in air commerce by prescribing
regulations for practices, methods, and procedures the Administrator
finds necessary for safety in air commerce. This regulation is within
the scope of that authority because it addresses an unsafe condition
that is likely to exist or develop on products identified in this
rulemaking action.

Regulatory Findings

    This AD will not have federalism implications under Executive Order
13132. This AD will not have a substantial direct effect on the States,
on the relationship between the national government and the States, or
on the distribution of power and responsibilities among the various
levels of government.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive
Order 12866,
    (2) Is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979), and
    (3) Will not have a significant economic impact, positive or
negative, on a substantial number of small entities under the criteria
of the Regulatory Flexibility Act.
    You can find our regulatory evaluation and the estimated costs of
compliance in the AD Docket.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator,
the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.

Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new AD:

2009-15-12 Boeing: Amendment 39-15975. Docket No. FAA-2007-28988;
Directorate Identifier 2007-NM-047-AD.

Effective Date

    (a) This airworthiness directive (AD) is effective August 25,
2009.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing Model 747-400 and -400D series
airplanes, certificated in any category; as identified in Boeing
Service Bulletin 747-24-2246, dated October 6, 2005.

Unsafe Condition

    (d) This AD results from an in-flight entertainment (IFE)
systems review. We are issuing this AD to ensure that the flightcrew
is able to turn off electrical power to the IFE system and other
non-essential passenger cabin systems through utility bus switches
in the flight compartment, in the event of smoke or fumes. The
flightcrew's inability to turn off electrical power to the IFE
system and other non-essential passenger cabin systems could result
in the inability to control smoke or fumes in the airplane flight
deck or passenger cabin during a non-normal or emergency situation.

Compliance

    (e) You are responsible for having the actions required by this
AD performed within the compliance times specified, unless the
actions have already been done.

Install New Relays

    (f) Within 60 months after the effective date of this AD,
install new relays to allow the flightcrew to turn off electrical
power to the IFE system and other non-essential passenger cabin
systems through the left and right utility bus switches and do all
other specified actions as applicable, by accomplishing all the
applicable actions specified in the Accomplishment Instructions of
Boeing Service Bulletin 747-24-2246, dated October 6, 2005. The
other specified actions must be done before further flight after
installing the new relays.

Alternative Methods of Compliance (AMOCs)

    (g)(1) The Manager, Seattle Aircraft Certification Office (ACO),
FAA, ATTN: Joe Salameh, Aerospace Engineer, Systems and Equipment
Branch, ANM-130S, FAA, Seattle ACO, 1601 Lind Avenue, SW., Renton,
Washington 98057-3356; telephone<PHONE_NUMBER>; fax<PHONE_NUMBER>; has
the authority to approve AMOCs for this AD, if requested using the
procedures found in 14 CFR 39.19.
    (2) To request a different method of compliance or a different
compliance time for this AD, follow the procedures in 14 CFR 39.19.
Before using any approved AMOC on any airplane to which the AMOC
applies, notify your principal maintenance inspector (PMI) or
principal avionics inspector (PAI), as appropriate, or lacking a
principal inspector, your local Flight Standards District Office.
The AMOC approval letter must specifically reference this AD.

Material Incorporated by Reference

    (h) You must use Boeing Service Bulletin 747-24-2246, dated
October 6, 2005, to do the actions required by this AD, unless the
AD specifies otherwise.
    (1) The Director of the Federal Register approved the
incorporation by reference of this service information under 5
U.S.C. 552(a) and 1 CFR part 51.
    (2) For service information identified in this AD, contact
Boeing Commercial Airplanes, Attention: Data & Services Management,
P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone
206-544-5000, extension 1; fax<PHONE_NUMBER>; e-mail
<EMAIL_ADDRESS>Internet https://www.myboeingfleet.com.
    (3) You may review copies of the service information at the FAA,
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington. For information on the availability of this material at
the FAA, call<PHONE_NUMBER> or<PHONE_NUMBER>.
    (4) You may also review copies of the service information that
is incorporated by reference at the National Archives and Records
Administration (NARA). For information on the availability of this
material at NARA, call<PHONE_NUMBER>, or go to: http://
www.archives.gov/federal_register/code_of_federal_regulations/
ibr_locations.html.

    Issued in Renton, Washington, on July 6, 2009.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E9-17118 Filed 7-20-09; 8:45 am]

BILLING CODE 4910-13-P


[Federal Register Volume 80, Number 30 (Friday, February 13, 2015)]
[Proposed Rules]
[Pages 8023-8030]
[FR Doc No: 2015-03064]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 60, 61, and 63

[EPA-HQ-OAR-2014-0738; FRL 9922-91-OAR]

Receipt of Approval Requests for the Operation of Pressure-
Assisted Multi-Point Ground Flare Technology

AGENCY: Environmental Protection Agency.

ACTION: Request for comments.

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SUMMARY: On August 5, 2014, The Dow Chemical Company (Dow) requested an
Alternative Means of Emission Limitation (AMEL) under the Clean Air Act
(CAA) in order to operate pressure-assisted multi-point ground flares
at its Propane Dehydrogenation Plant and its Light Hydrocarbons Plant
at its Texas Operations site located in Freeport, Texas. On October 21,
2014, ExxonMobil Chemical Company (ExxonMobil) requested an AMEL under
the CAA for its pressure-assisted multi-point ground flares at its'
Olefins Plant in Baytown, Texas, and its' Plastics Plant in Mont
Belvieu, Texas. In this document, the Environmental Protection Agency
(EPA) is soliciting comment on all aspects of the AMEL requests and the
resulting alternative operating conditions that are necessary to
achieve a reduction in emissions of volatile organic compounds (VOC)
and hazardous air pollutants (HAPs) at least equivalent to the
reduction in emissions required by various standards in 40 CFR parts
60, 61 and 63 that apply to emission sources controlled by these
pressure-assisted multi-point ground flares. These standards point to
the operating requirements for flares in the General Provisions to
parts 60 and 63, respectively, to comply with the emission reduction
requirements. Because pressure-assisted multi-point ground flares
cannot meet the velocity requirements in these General Provisions, Dow
and ExxonMobil are seeking an AMEL.

DATES: Comments. Written comments must be received on or before March
30, 2015.
    Public Hearing. If requested by February 18, 2015, we will hold a
public hearing on March 2, 2015, from 1:00 p.m. [Eastern Standard Time]
to 5:00 p.m. [Eastern Standard Time] at EPA's Campus located in
Research Triangle Park, NC. We will provide details on the public
hearing on our Web site at: http://www.epa.gov/ttn/atw/groundflares/groundflarespg.html. To be clear, a public hearing will not be held
unless someone specifically requests that the EPA hold a public hearing
regarding these requests. Please contact Ms. Virginia Hunt of the
Sector Policies and Programs Division (E143-01), Office of Air Quality
Planning and Standards, Environmental Protection Agency, Research
Triangle Park, NC 27711; telephone number:<PHONE_NUMBER>; email
address<EMAIL_ADDRESS>to request a public hearing, to
register to speak at the public hearing or to inquire as to whether or
not a public hearing will be held. The last day to pre-register in
advance to speak at the public hearing will be February 25, 2015.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA OAR-
2014-0738, by one of the following methods:
     http://www.regulations.gov. Follow the on-line
instructions for submitting comments.
     Email<EMAIL_ADDRESS>Attention Docket ID Number
EPA-HQ-OAR-2014-0738.
     Fax:<PHONE_NUMBER>. Attention Docket ID Number EPA-HQ-
OAR-2014-0738.
     Mail: U.S. Postal Service, send comments to: EPA Docket
Center (EPA/DC), Attention Docket ID Number EPA-HQ-OAR-2014-0738, U.S.
Environmental Protection Agency, Mailcode: 28221T, 1200 Pennsylvania
Ave. NW., Washington, DC 20460.
     Hand Delivery: U.S. Environmental Protection Agency, EPA
WJC West Building, Room 3334, 1301 Constitution Ave. NW., Washington,
DC 20004. Attention Docket ID Number EPA-HQ-OAR-2014-0738. Such
deliveries are only accepted during the Docket's normal hours of
operation, and special arrangements should be made for deliveries of
boxed information.
    Instructions. Direct your comments to Docket ID Number EPA-HQ-OAR-
2014-0738. The EPA's policy is that all comments received will be
included in the public docket without change and may be made available
online at http://www.regulations.gov, including any personal
information provided, unless the comment includes information claimed
to be confidential business information (CBI) or other information
whose disclosure is restricted by statute. Do not submit information
that you consider to be CBI or otherwise protected through http://www.regulations.gov or email. The http://www.regulations.gov Web site
is an ``anonymous access'' system, which means the EPA will not know
your identity or contact information unless you provide it in the body
of your comment. If you send an email comment directly to the EPA
without going through http://www.regulations.gov, your email address
will be automatically captured and included as part of the comment that
is placed in the public docket and made available on the Internet. If
you submit an electronic comment, the EPA recommends that you include
your name and other contact information in the body of your comment and
with any disk or CD-ROM you submit. If the EPA cannot read your comment
due to technical difficulties and cannot contact you for clarification,
the EPA may not be able to consider your comment. Electronic files
should not include special characters or any form of encryption and be
free of any defects or viruses. For additional information about the
EPA's public docket, visit the EPA Docket Center homepage at: http://www.epa.gov/dockets.
    Docket. The EPA has established a docket for this rulemaking under
Docket ID Number EPA-HQ-OAR-2014-0738. All documents in the docket are
listed in the regulations.gov index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, is not placed on the Internet and will be
publicly available only in hard copy. Publicly available docket
materials are available either electronically in regulations.gov or in
hard copy at the EPA Docket Center (EPA/DC), EPA WJC West Building,
Room 3334, 1301 Constitution Ave. NW., Washington, DC. The Public
Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through
Friday, excluding legal holidays. The telephone number for the Public
Reading Room is<PHONE_NUMBER>, and the telephone number for the EPA
Docket Center is<PHONE_NUMBER>.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed
action, contact Ms. Brenda Shine, Sector Policies and Programs Division
(E143-01), Office of Air Quality Planning and Standards (OAQPS), U.S.
Environmental Protection Agency, Research Triangle Park, North Carolina
27711; telephone number:<PHONE_NUMBER>; fax number:<PHONE_NUMBER>;
and email address<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

Acronyms and Abbreviations

    We use multiple acronyms and terms in this document. While this
list may not be exhaustive, to ease the reading of this document and
for reference purposes, the EPA defines the following terms and
acronyms here:

AMEL alternative means of emission limitation
BOP Baytown Olefins Plant
Btu/scf British thermal units per standard cubic feet
LFL lower flammability limit
LFLcz combustion zone lower flammability limit
LHC Light Hydrocarbons Unit
LRGO Linear relief gas oxidizer
MACT maximum achievable control technology
MBPP Mont Belvieu Plastics Plant
MPGF multi-point ground flare
NESHAP national emission standard for hazardous air pollutants

NHV net heating value
NHVcz combustion zone net heating value
NSPS new source performance standards
OAQPS Office of Air Quality Planning and Standards
PDH Propylene Dehydrogenation Unit
PFTIR passive fourier transform infrared
SKEC steam-assisted kinetic energy combustor

    Organization of This Document. The information in this document is
organized as follows:

I. Statutory and Regulatory Background
    A. Flare Operating Requirements
    B. Alternative Means of Emission Limitation
II. Requests for Alternative Means of Emission Limitation
    A. Dow AMEL
    B. ExxonMobil AMEL
    C. EPA's Analysis of MPGF Burner Emission Tests
III. AMEL for Pressure-Assisted MPGF
IV. Request for Comments

I. Statutory and Regulatory Background

A. Flare Operating Requirements

    In their requests, Dow and ExxonMobil cite various regulatory
requirements in 40 CFR parts 60, 61 and 63 that will apply to the
different vent gas streams that will be collected and routed to their
pressure-assisted multi-point ground flares (MPGF) at each plant. These
requirements are included in Table 1.\1\ In all cases, these rules
reference the flare operating requirements located in 40 CFR 60.18 and
40 CFR 63.11.
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    \1\ EPA prepared Table 1 using the information provided in the
requests, corrected as appropriate based on its own review of the
regulations. However, the EPA has not independently verified whether
Table 1 includes all of the regulatory requirements with which these
plants must comply.

             Table 1--Summary of Applicable Rules That May Apply to Vents Streams Controlled by Pressure-Assisted Multi-Point Ground Flares
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Provisions for
   Applicable rules with vent         Dow propane      Dow light hydro-       Exxon-Mobil      Exxon-Mobil Mont   Emission reduction   alternative means
    streams going to  control       dehydrogenation      carbons (LHC)      Baytown Olefins    Belvieu plastics       required and        of emission
             device                   (PDH) plant            plant               plant               plant           rule citation        limitation
--------------------------------------------------------------------------------------------------------------------------------------------------------
NSPS Subpart Kb.................  ..................                  X                   X   ..................  60.112b(a)(3)(ii)-  60.114b allows for
                                                                                -Reduce VOC inlet   AMEL.
                                                                                emissions by 95%;
                                                                                If a flare is
                                                                                used as a control
                                                                                device, flare
                                                                                must meet
                                                                                requirements of
                                                                                60.18.
NSPS Subparts VV/Vva............                  X                   X                   X   ..................  60.482-10a--Reduce  60.484(a) allows
                                                                                VOC emissions by    for AMEL
                                                                                95% or greater;
                                                                                flare used to
                                                                                comply with
                                                                                subpart must meet
                                                                                requirements of
                                                                                60.18.
                                                                                *Note--Under Dow
                                                                                PDH Plant column,
                                                                                NSPS subpart VVa
                                                                                applies, but DOW
                                                                                is opting to
                                                                                comply with 40
                                                                                CFR part 63,
                                                                                subpart H (as
                                                                                referenced by
                                                                                Miscellaneous
                                                                                Organic
                                                                                NESHAP(MON) which
                                                                                should satisfy
                                                                                requirements in
                                                                                subpart VVa.
NSPS Subpart DDD................  ..................  ..................  ..................                  X   60.562-1--Reduce    CAA section
                                                                                emissions of        111(h)(3) allows
                                                                                Total Organic       for AMEL.
                                                                                Carbon (TOC) by
                                                                                98%, or combust
                                                                                in a flare that
                                                                                meets the
                                                                                requirements of
                                                                                60.18.
NSPS Subpart NNN................                  X                   X                   X                   X   60.662- Reduce      CAA section
                                                                                emissions of TOC    111(h)(3) allows
                                                                                by 98%, or          for AMEL.
                                                                                combust in a
                                                                                flare that meets
                                                                                the requirements
                                                                                of 60.18.
NSPS Subpart RRR................                  X                   X                   X                   X   60.702--Reduce      CAA section
                                                                                emissions of TOC    111(h)(3) allows
                                                                                by 98%, or          for AMEL.
                                                                                combust in a
                                                                                flare that meets
                                                                                the requirements
                                                                                of 60.18.

NESHAP Subpart V................  ..................  ..................                  X   ..................  61.242-11(d)--flar  61.244 allows for
                                                                                es used to comply   AMEL; also see
                                                                                with subpart V      61.12(d).
                                                                                must comply with
                                                                                60.18.
NESHAP Subpart FF...............  ..................                  X                   X   ..................  61.349(a)--reduce   61.353 allows for
                                                                                organic emissions   AMEL; also see
                                                                                vented to control   61.12(d).
                                                                                device by 95%; a
                                                                                flare shall
                                                                                comply with the
                                                                                requirements of
                                                                                60.18.
NESHAP Subparts F, G............  ..................  ..................                  X   ..................  63.102, 63.113,     63.102(b) allows
                                                                                63.126--Reduce      for AMEL.
                                                                                emissions of
                                                                                Total Organic HAP
                                                                                (TOHAP) by 98%,
                                                                                or combust in a
                                                                                flare that meets
                                                                                the requirements
                                                                                of 63.11(b).
                                                                                63.120--Combust in
                                                                                flare meeting
                                                                                63.11. 63.139--
                                                                                Reduce emissions
                                                                                of TOHAP by 95%,
                                                                                or combust in a
                                                                                flare that meets
                                                                                the requirements
                                                                                of 63.11(b).
                                                                                63.145(j)--Points
                                                                                to sections of
                                                                                63.11(b) for
                                                                                flare control.
NESHAP Subpart H................                  X   ..................                  X   ..................  63.172--Reduce      63.177 allows for
                                                                                organic HAP or      AMEL.
                                                                                VOC by 95%;
                                                                                flares used to
                                                                                comply must meet
                                                                                requirements of
                                                                                63.11(b).
NESHAP Subpart SS...............                  X                   X                   X                   X   63.982(b) and       CAA section
                                                                                63.987(a) require   112(h)(3) allows
                                                                                that a flare        for AMEL.
                                                                                meets the
                                                                                requirements in
                                                                                63.11(b).
NESHAP Subpart UU...............  ..................                  X   ..................  ..................  63.1034--Nonflare   63.1021 allows for
                                                                                control devices     AMEL.
                                                                                shall reduce
                                                                                emissions by 95%;
                                                                                flares shall
                                                                                comply with
                                                                                subpart SS.
NESHAP Subpart XX...............  ..................                  X   ..................  ..................  63.1091 requires    61.353 allows for
                                                                                compliance with     AMEL; also see
                                                                                subpart FF, which   61.12(d).
                                                                                requires
                                                                                compliance with
                                                                                60.18.
NESHAP Subpart YY...............  ..................                  X                   X   ..................  Table 7 references  63.1113 allows for
                                                                                subpart SS, which   AMEL.
                                                                                requires
                                                                                compliance with
                                                                                60.18.
NESHAP Subpart EEEE.............  ..................  ..................                  X                   X   63.2378(a)          63.2346(g) allows
                                                                                references          for AMEL; also
                                                                                subpart SS, which   see Table 12
                                                                                requires            which makes
                                                                                compliance with     63.6(g)
                                                                                60.18.              applicable to
                                                                                this subpart.

NESHAP Subpart FFFF.............                  X   ..................  ..................                  X   63.2450 requires    63.2540 and Table
                                                                                compliance with     12 allow for AMEL
                                                                                limits in Tables    by making 63.6(g)
                                                                                1-7, which          applicable to
                                                                                include reducing    this subpart.
                                                                                total organic HAP
                                                                                in vent streams
                                                                                by either 95% or
                                                                                98%, and provide
                                                                                an option for
                                                                                control using a
                                                                                flare meeting
                                                                                requirements of
                                                                                63.982(b) which
                                                                                requires meeting
                                                                                63.987, which
                                                                                requires a flare
                                                                                to meet the
                                                                                requirements of
                                                                                63.11(b).
--------------------------------------------------------------------------------------------------------------------------------------------------------

    As shown in Table 1, the applicable rules require that control
devices achieve destruction efficiencies of either 95 percent or 98
percent either directly, or by reference, or allow control by flares
meeting the flare operating requirements in 40 CFR 60.18 or 63.11. The
flare operating requirements in 40 CFR 60.18 and 63.11 specify that
flares shall be: (1) Steam-assisted air-assisted, or non-assisted; \2\
(2) operated at all times when emissions may be vented to them; (3)
designed for and operated with no visible emissions (except for periods
not to exceed a total of 5 minutes during any 2 consecutive hours); and
(4) operated with the presence of a pilot flame at all times. The flare
operating requirements in 40 CFR 60.18 and 63.11 also specify
requirements for both the minimum heat content of gas combusted in the
flare and the maximum exit velocity at the flare tip.\3\ These
provisions specify maximum flare tip velocities based on flare type
(non-assisted, steam-assisted or air-assisted) and the net heating
value of the flare vent gas (see 40 CFR 60.18(c)(3), 63.11(b)(6)).
These maximum flare tip velocities are required to ensure that the
flame does not ``lift off'' or separate from the flare tip, which could
cause flame instability and/or potentially result in a portion of the
flare gas being released without proper combustion. Proper combustion
for flares is considered to be 98 percent destruction efficiency or
greater for HAPs and VOCs, as discussed in our recent proposal titled
''Petroleum Refinery Sector Risk and Technology Review and New Source
Performance Standards,'' 79 FR 36,880, 36,904-36,912 (June 30, 2014).
---------------------------------------------------------------------------

    \2\ While Dow and ExxonMobil describe their flares as
``pressure-assisted,'' these flares qualify as ``non-assisted''
flares under 40 CFR 60.18(b) or 63.11(b) because they do not employ
assist gas.
    \3\ These requirements are not all inclusive. There are other
requirements in 40 CFR 60.18 and 63.11 relating to monitoring and
testing that are not described here.
---------------------------------------------------------------------------

    The MPGF proposed by both Dow and ExxonMobil are conceptually
similar yet inherently different in both flare head design and
operation than the more traditional steam-assisted, air-assisted and
non-assisted flare types currently able to comply with the flare
operating requirements in 40 CFR 60.18 or 63.11. The MPGF technology
operates by using the pressure upstream of each individual flare tip
burner to enhance mixing with air at the flare tip due to high exit
velocity, which allows the MPGF to operate with smokeless burning. The
MPGF are constructed differently than normal elevated flares in that
they consist of many rows of individual flare tips which are
approximately 8 feet above ground level. The ground flare staging
system opens and closes staging valves according to gas pressure such
that stages containing multiple burners are activated as the flow and
pressure increase or decrease in the header. While information supplied
by Dow, and relied on by both Dow and ExxonMobil, indicates that the
flare tips operate smokelessly and achieve high destruction
efficiencies, the MPGF cannot meet the exit velocity requirements in 40
CFR 60.18 and 40 CFR 63.11, which limit the exit velocity at the flare
tip to a maximum of 400 feet per second. The exit velocities from MPGF
typically range from 600 feet per second up to sonic velocity (which
ranges from 700 to 1,400 feet per second for common hydrocarbon gases),
or Mach =1 conditions. As a result, Dow and ExxonMobil are seeking an
alternative means of complying with the flare operating requirements in
40 CFR 60.18 and 63.11; specifically, the exit velocity requirements in
40 CFR 60.18(c)(3), (c)(4), and (c)(5) and in 40 CFR 63.11(b)(6),(b)(7)
and (b)(8).

B. Alternative Means of Emission Limitation

    As noted in Table 1, the specific rules in 40 CFR parts 60, 61 and
63, or the General Provisions for parts 60, 61 and 63 of the CAA \4\
allow a facility to request an AMEL. These provisions allow the
Administrator to permit the use of an alternative means of complying
with an applicable standard, if the requestor demonstrates that the
alternative achieves at least an equivalent reduction in emissions. The
EPA must provide notice of the request and an opportunity for a public
hearing on the request. After considering comments received, the EPA
will issue a notice permitting the use of an

alternative means of emission limitation, if the Administrator
determines that the alternative will achieve an equivalent reduction in
emissions.
---------------------------------------------------------------------------

    \4\ CAA section 111(h)(3) states: ``If after notice and
opportunity for public hearing, any person establishes to the
satisfaction of the Administrator that an alternative means of
emission limitation will achieve a reduction in emissions of any air
pollutant at least equivalent to the reduction in emissions of such
air pollutant achieved under the requirements of paragraph (1), the
Administrator shall permit the use of such alternative by the source
for purposes of compliance with this section with respect to such
pollutant.'' Section 112(h)(3) contains almost identical language.
---------------------------------------------------------------------------

II. Requests for Alternative Means of Emission Limitation

A. Dow AMEL

    In its August 5, 2014, request, Dow indicates that it plans to
construct and operate two new MPGFs at its Texas Operations site in
Freeport, TX. One MPGF would be located at Dow's Propane
Dehydrogenation Plant (PDH-1), scheduled to start-up in early 2015 and
whose primary product is propylene. The other MPGF would be located at
Dow's Light Hydrocarbons Plant (LHC-9), scheduled to start-up in early
2017 and whose primary product is ethylene.
    The flare systems proposed for use by Dow at both plants consist of
a staged design concept. The first stage, which is not at issue nor
specifically part of the notice requesting an AMEL because it can meet
the flare operating requirements of 40 CFR of 60.18 and 63.11, is a
steam-assisted ground flare which has the primary function of
controlling waste gases during periods of normal operation. The
remaining stages consist of arrays of pressure-assisted flare tips (the
MPGFs) and will control waste gases during periods of upset,
maintenance, startup and shutdown (high-pressure, high flow periods).
Pressure-assisted flares are also known as sonic flares because the
exit velocity during periods of high-pressure feeds is at sonic
velocities.
    At Dow, Stage 1 is the low pressure stage in which the flare acts
as a steam-assisted flare. Stages 2 and beyond are activated for high-
pressure/high exit velocity flows. The flare system is surrounded by a
panel type fence to protect nearby workers from the radiant heat from
the flare system. At various times ranging from 2 hours for startup of
processing equipment to 160 hours for a complete plant shutdown, Dow
will have emissions from the MPGF for the following maintenance, start-
up and shutdown (MSS) activities: Perform plant start-up and shutdown,
process equipment startup and shutdown, off-spec flaring, non-routine
clearing and commissioning of process equipment and piping, fuel
purging and flaring to maintain pressure of the net-gas system.
    Dow conducted testing on the two types of individual flare tips in
its MPGF design to demonstrate that the MPGF can achieve good
combustion efficiency under certain conditions and has proposed
operating requirements for these MPGF that can achieve the emissions
standards in the applicable NSPS and NESHAP. These proposed operating
requirements are contained in Dow's request dated August 5, 2014,
located in the docket for this document. A summary of test data and a
complete copy of the emission testing report and appendices are
available in the docket. The tests were conducted on individual flare
tips because it is not possible to test the full field of MPGF because
of the size and configuration of the full-scale MPGF installation
(there are approximately 300 flare tips in the proposed array pattern
that cover the size approximately equivalent to that of a football
field in the actual installations). Although two flare tip types were
tested during the effort, the results of one burner type, a steam-
assisted flare burner, John Zink model SKEC, are not discussed further
as Dow is not seeking an AMEL for this burner because it operates at
lower velocity and, thus, can meet the existing flare operating
requirements.

B. ExxonMobil AMEL

    In its October 21, 2014, request, ExxonMobil indicates it plans to
construct and operate two MPGFs, one at its Baytown Olefins Plant (BOP)
in Baytown, TX, and the other at its Mont Belvieu Plastics Plant (MBPP)
in Mont Belview, TX. Both of the proposed control strategies will be
designed such that vent gases are routed to either a low pressure
system, or in infrequent cases where high-pressure/high flow events
occur, the high pressure MPGF. Both low pressure control systems at the
BOP and MBPP consist of an elevated flare, but the MBPP low pressure
control system also consists of three flameless thermal oxidizers. The
elevated flares at both the BOP and MBPP will comply with 40 CFR 60.18
and/or 40 CFR 63.11, as applicable.
    ExxonMobil did not supply any additional test data, but rather is
relying on a series of publically available MPGF emissions tests, among
them the 2013 test submitted by Dow, a 2012 test done by Marathon
Petroleum Corporation, LP, a 2006 pipeline burner test done by Dow, and
two earlier tests conducted by the EPA in the 1980s. ExxonMobil
indicates that the BOP and MBPP burner tip designs will have comparable
performance to the burners recently tested and submitted December 14,
2014, supplemental application containing additional information on
plans to use the John Zink LRGO burners for the MPGF installation at
the MBPP, and ZEECO burners at the BOP. ExxonMobil asserts that the
ZEECO burner design provides equivalent combustion efficiency and flame
stability as that of the John Zink burners tested, although ExxonMobil
has not supplied any data or information that could confirm this
assertion of equivalency. We are requesting comment on this assertion
as well as specifically soliciting data and comments from the public on
burner design and performance of these MPGF burners.

C. EPA's Analysis of MPGF Burner Emission Tests

    Dow and ExxonMobil are proposing to follow all of the flare
operating requirements contained in either 40 CFR 60.18 or 63.11,
except for the exit velocity requirements. They are proposing to
operate their high pressure MPGFs at higher velocity than the current
requirements because their data indicate that these burners can operate
with a stable flame at higher velocities and still achieve good
combustion and destruction efficiencies. Instead of complying with the
exit velocity requirements in 40 CFR 60.18 and 63.11, Dow and
ExxonMobil are requesting that EPA grant their AMEL requests to allow
them to operate the high pressure sections of their MPGFs such that the
vent gas flowing to the flare tips is maintained with a net heating
value that has been demonstrated to be equal to or greater than the
values that were determined to achieve a reduction in emissions of
pollutants being controlled by a steam-assisted, air-assisted or non-
assisted flare complying with the requirements of either 40 CFR
63.11(b) or 40 CFR 60.18(b) during the burner emission tests.
    In the emission tests, the high pressure burners were subjected to
a number of different operating conditions, and each set of conditions
represented a separate test series. For purposes of this discussion,
the relevant test results are those from Dow's 2013 test report, which
are comprised of runs from test series P1 through P4 and were tested on
John Zink's pressure assisted flare burner model LRGO-HC, as well as
emissions data reported in Marathon's 2012 test report, which are from
test series PA1 and PA2 and were tested on John Zink's pressure
assisted flare burner model LRGO-D. These tests used the analytical
technique of passive fourier transform infrared (PFTIR) spectroscopy to
assess combustion efficiency. Dow's 2013 test report also presents data
collected using an extractive method where flue gas was extracted from
a collection hood that was suspended above the burner tip and analyzed
using standard EPA methods.

The Marathon 2012 test report (see ``Performance Test of Steam-Assisted
and Pressure-Assisted Ground Flare Burners with Passive FTIR--
Garyville'') and the Dow 2013 test report (see ``Report on Emissions
Testing of Pressure Assisted LRGO-HC and Steam Assisted SKEC Burners'')
are provided in the docket.
    The results of the PFTIR testing indicated that when a flame was
present on the pressure-assisted flare burners tested that an average
combustion efficiency of 99 percent or greater was always achieved.
Each set of operating conditions tested by both Dow and Marathon for
both combustion efficiency and flame stability generally consisted of a
series of triplicate runs. In all, a total of 34 test runs were
analyzed from these two tests (21 from Dow's P1 through P3 test series
and 13 from Marathon's PA1 and PA2 test series). For test series P4,
which was conducted as part of Dow's 2013 test using a 90 volume
percent hydrogen/10 volume percent natural gas mixture, no combustion
efficiency test was conducted; instead, a qualitative indication that
the flame was stable at the conditions tested was made. We note that in
Dow's 2013 test report that three of the 21 test runs were aborted
because of loss of flame (which we refer to as flameout); only two of
the three test runs (one in the P2H series and one in the P2L series)
produced enough information before flameout to be analyzed in more
detail. We requested more detailed information from Dow on the
conditions that resulted in this loss of flame as it informs us of the
conditions that would create a failure of the burners to sustain a
stable flame and achieve good combustion. This document is included in
the docket titled ``Supplement 1 to Dow report.'' Additionally, we also
note that in Marathon's 2012 test report that two of the 13 test runs
also experienced loss of flame (test PA1 Runs 4(2) and 4(4)). The
results of all of these test runs are discussed in the memorandum
titled ``Review of Available Test Data on Multipoint Ground Flares,''
located in the docket.
    There are two general conclusions from these test reports that are
consistent with the earlier EPA 1985 study done on pressure-assisted
flares (see conclusions on pages 2-19 and 2-22 in September 1985 EPA
report titled ``Evaluation of the efficiency of industrial flares:
Flare head design and gas composition''). The first is that ``flare
head design can influence the flame stability curve.'' This is evident
in Figures 2-3 and 2-5 of the 1985 EPA report where different stability
curves were generated for the different flare heads (burners) tested
over a range of differing exit velocities and flare gas net heating
values. When comparing the current maximum flare tip velocity
requirements in the general provisions with those tested on pressure-
assisted flare burners, this conclusion still holds true. The agency's
current requirements would require that flares meet an increasing
minimum net heating value with increasing velocity, all the way up to a
minimum waste gas net heating value of 1,000 BTU/scf and maximum
velocity of 400 feet per second. However, the recent test reports on
pressure-assisted burners show that flame stability can be achieved at
significantly higher velocities (i.e., sonic velocity) with waste gas
net heating values below 1,000 BTU/scf. The second general conclusion
made from EPA's 1985 study is that ``stable flare flames and high (>98-
99) combustion and destruction efficiencies are attained when flares
are operated within operating envelopes specific to each flare burner
and gas mixture tested. Operation beyond the edge of the operating
envelope can result in rapid flame de-stabilization and a decrease in
combustion and destruction efficiencies.'' The data where flameout of
the burners occurred from test runs in both the Marathon 2012 test
report and the Dow 2013 test report showed that the flare operating
envelope was different for the different gas mixtures tested.
Additionally, it was observed that combustion degradation beyond the
edge of the operating envelope for pressure-assisted MPGF burners was
so rapid that when a flame was present, the flare would still achieve a
high level of combustion efficiency right up until the point of
flameout.
    In order to assess the proper operating envelope for these flare
types, the EPA evaluated both the net heating value (in BTU/scf), which
is how the 40 CFR part 60 and 63 General Provisions currently address
combustion zone properties, as well as the lower flammability limit
(LFL) because the LFL may be a better indicator of performance than net
heating value for some flare vent gas streams, notably those with the
potential for high hydrogen content. Hydrogen is relatively flammable,
but its net heating value is low on a BTU/scf basis when compared to
other hydrocarbons. By using LFL, we eliminate the need to correct the
hydrogen heat content or to select a lower BTU/scf limit for high
hydrogen cases. Although Dow has requested operating limits in the form
of BTU/scf and has presented the test data in BTU/scf, we believe it is
important to consider both types of operating limits.
    Our review indicates that the LRGO burners tested achieve a high
level of combustion efficiency when the lower flammability limit of
waste gases burned in the flare is less than 6.5 volume percent (vol%)
LFL or above 800 BTU/scf. We suggest the 6.5 vol% LFL based on the
flammability of the stream during the flame out conditions experienced
during the high pressure test run P2H1 (at 6.6 vol% LFL). The
corresponding BTU content of the waste gas at this value was 789 BTU/
scf (according to Dow, the gas chromatograph analysis indicated this
value was 746 BTU/scf, although the John Zink report based on measured
flow rates indicated it was 789 BTU/scf). Dow's proposed operating
conditions included startup/shutdown cases where the waste gas heat
content could be as low as 690 BTU/scf and as high as 6.9 vol% LFL, and
data from these tests indicate that good combustion can occur at these
conditions. However, to establish the alternative operating
requirements at a level that ensures good combustion and flame
stability at all times under all operating conditions, we believe it is
reasonable to establish the heat content requirements for BTU/scf above
which there were no flame out observations. For LFL, that level would
be set below which there are no flame out observations. This is because
gas mixtures with a relatively high LFL are less flammable when
released to the air than mixtures with a relatively low LFL. A gas
mixture with a relatively high LFL requires a larger volume of the
mixture to burn in a specific volume of air, than would a mixture of
gases with a relatively low LFL being combusted in that same volume of
air. We believe the flame out observations establish the limiting case
because a flameout is a complete failure of the burner, indicating
zero-percent combustion. Because of the quantity of waste gases
potentially flared in the high-pressure zones of these MPGF, we believe
it would be prudent to establish limits on the conservative side to
prevent air emissions of unburned waste gas.
    We also reviewed whether we should consider velocity or burner
operating pressure in describing conditions that should be met during
the MPGF operation and whether we should require some testing to ensure
that the individual burners will ignite properly when a new stage goes
into service. Dow provided information on its process control system
and indicated that cross-light testing (testing of burner ignition from
pilots) of individual burners at its off-site test facility has been
conducted

and the burners performed as expected. This discussion, titled
``Process control system overview-multipoint ground flare system,'' is
in the docket for this action. At this time, we are not considering any
requirements for additional process control or ignition testing.
However, we believe it would be important to require that cameras are
installed and operated such that operators have a visual indication of
flames from the flare at all times that the MPGF is operating and that
this footage be available for inspection by the permitting agency,
along with operational records of the waste gas flowrate, pressure in
header and stages, pilot and waste gas composition.
    Because these flares are located at ground level, it is possible
that ambient concentrations of pollutants could be higher than they
would be under an alternative scenario where waste gases would be
flared in an elevated flare, enabling greater dispersion and
potentially lessening the impact to neighboring communities. To that
end, we are soliciting comment on whether additional ambient monitoring
is warranted to provide for immediate notification to emergency
planning officials and the community during significant events and
malfunctions of the system.

III. AMEL for Pressure-Assisted MPGF

    Considering the above requests from both Dow and ExxonMobil, we are
seeking the public's input on the operating requirements for the
proposed pressure-assisted MPGFs that would be used by both companies
which would establish an AMEL that will achieve a reduction in
emissions at least equivalent to the reduction in emissions being
controlled by a steam-assisted, air-assisted or non-assisted flare
complying with the requirements of either 40 CFR 63.11(b) or 40 CFR
60.18(b). Information provided in the AMEL requests and the available
emissions test data from the test reports described above indicate that
the following list of operating requirements for pressure-assisted MPGF
result in destruction efficiencies at least equivalent to destruction
efficiencies expected from complying with the requirements of 40 CFR
63.11(b) and 40 CFR 60.18(b) for the pressure-assisted MPGF being
proposed for use by both Dow and ExxonMobil:
    1. The flare system must be designed and operated such that the net
heating value of the combustion zone gas (NHVcz) for the
pressure assisted flare burners meets a minimum heating value of 800
BTU/scf or a lower flammability limit of the combustion zone gas
(LFLcz) of less than or equal to 6.5 percent by volume under
all conditions. We would expect owners or operators to calculate
NHVcz and LFLcz in a manner similar to those in
the currently proposed requirements of 79 FR 36980-40 CFR 63.670(l)-
(m).
    2. The flare system must be operated with a flame present at all
times when in use. Each row of flare burners must have at least one
pilot with a constant pilot flame. The pilot flame(s) must be
continuously monitored by a thermocouple. The time, date and duration
of any loss of pilot flame must be recorded. Each monitoring device
must be maintained or replaced at a frequency in accordance with the
manufacturer's specifications.
    3. The flare system must be operated with no visible emissions
except for periods not to exceed a total of 5 minutes during any 2
consecutive hours. A video camera can be used in order to conduct
visible emission observations since operating personnel cannot enter
the fenced area while the MPGF is operating.
    4. The operator must install and operate an on-line vent gas flow
meter and an on-line gas chromatograph to measure the flow and
composition of the vent gas to each flare. We would expect the operator
to comply with similar monitoring and testing requirements and
recordkeeping and reporting requirements for these monitoring systems
as currently proposed in 79 FR 36980-40 CFR 63.670(i)-(j) and (l)-(m).
    5. The operator should install and operate pressure and/or flow
monitors on each stage of the flare. We would expect the operator to
comply with similar applicable monitoring and testing requirements and
recordkeeping and reporting requirements for these monitoring systems
as currently proposed in 79 FR 36980-40 CFR 63.670(i).

IV. Request for Comments

    We solicit comments on all aspects of these requests for an AMEL.
We specifically seek comment regarding whether or not the potential
alternative operating requirements listed in section III above would be
adequate for ensuring that the MPGF will achieve good combustion at all
times and enable the facilities to meet their applicable emission
standards. Additionally, several other entities have indicated to us
that they intend to make similar requests for the ability to operate
pressure-assisted MPGFs. We are also soliciting comment on whether the
requirements listed above, if followed by these other entities, could
enable these other facilities to receive approval of their own AMELs.
As noted in section II.B above, we also solicit comment and data on
other pressure-assisted flare burner types. Commenters should include
data or specific examples in support of their comments.

    Dated: February 3, 2015.
Janet G. McCabe,
Acting Assistant Administrator.
[FR Doc. 2015-03064 Filed 2-12-15; 8:45 am]
BILLING CODE 6560-50-P