[Federal Register Volume 62, Number 37 (Tuesday, February 25, 1997)]
[Rules and Regulations]
[Pages 8402-8404]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-4614]
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DEPARTMENT OF TRANSPORTATION
Research and Special Programs Administration
49 CFR Part 193
[Docket No. PS-151; Amdt. 193-13]
RIN 2137-AC 91
Liquefied Natural Gas Regulations--Miscellaneous Amendments
AGENCY: Research and Special Programs Administration (RSPA), DOT.
ACTION: Direct final rule.
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SUMMARY: This direct final rule updates the Liquefied Natural Gas (LNG)
regulations by replacing the current ``Flammable vapor-gas dispersion
protection'' method with a method based on the ``dense gas dispersion
(DEGADIS)'' model, and replacing the current ``Thermal Radiation
Protection'' method with a method based on the ``LNGFIRE'' program
model. In addition, this final rule incorporates safety requirements
for mobile and temporary LNG facilities by referring to the National
Fire Protection Association (NFPA) Standard 59A (1996 edition)--
Standard for the Production, Storage and Handling of Liquefied Natural
Gas (LNG).
DATES: This direct final rule takes effect June 25, 1997 unless RSPA
receives adverse comments or notice of intent to file adverse comment
by April 28, 1997. The incorporation by reference of certain
publications listed in the rule is approved by the Director of the
Federal Register as of June 25, 1997. If RSPA does not receive any
adverse comment or notice of intent to file an adverse comment by April
28, 1997 the rule will become effective on the date specified. RSPA
will issue a subsequent notice in the Federal Register by May 27, 1997
after the close of the comment period to confirm that fact and
reiterate the effective date. If an adverse comment or notice of intent
to file an adverse comment is received, RSPA will issue a timely notice
in the Federal Register to confirm that fact and RSPA would withdraw
the direct final rule in whole or in part. RSPA may then incorporate
the adverse comment into a subsequent direct final rule or may publish
a notice of proposed rulemaking.
ADDRESSES: Written comments must be submitted in duplicate and mailed
or hand-delivered to the Dockets Unit, room 8421, U.S. Department of
Transportation, Research and Special Programs Administration, 400
Seventh Street, SW., Washington, DC 20590. Identify the docket and
notice numbers stated in the heading of this notice. All comments and
materials cited in this document will be available for inspection and
copying in room 8421 between 8:30 a.m. and 4:30 p.m. each business day.
Non-federal employee visitors are admitted to the DOT headquarters
building through the southwest quadrant entrance at Seventh and E
Streets.
FOR FURTHER INFORMATION CONTACT: Mike Israni, (202) 366-4571, regarding
the subject matter of this document, or the Dockets Unit (202) 366-
4453, for copies of this document or other information in the docket.
SUPPLEMENTARY INFORMATION:
Background
Section 193.2019 Mobile and Temporary LNG Facilities
RSPA is amending 49 CFR Part 193 by adding a section 193.2019 on
mobile and temporary LNG facilities. Mobile and temporary LNG
facilities have a good safety record and their use has become quite
common. However, Part 193 currently does not contain requirements for
such temporary operations and many temporary operations cannot meet
some of the Part 193 requirements. In those cases, operations have been
authorized through waivers issued by the relevant states, and approved
by RSPA, for mobile and temporary facilities for peakshaving
applications, for service maintenance during gas pipeline systems
repair/alteration, or for other short term applications. In acting on
waiver requests, RSPA reviews justification for not complying with Part
193 and requires alternative safety provisions to maintain public
safety. There has been no adverse impact on safety as a result of the
waiver process and RSPA anticipates an equivalent level of safety
following implementation of this direct final rule. The safety
guidelines and the restrictions for LNG mobile facilities in section 2-
3.4 of the NFPA 59A (1996 edition) provide an adequate level of
assurance of public safety. The safety guidelines are identical to
those required as conditions for waiver. Thus, we do not see any
necessity for issuing a proposed rule. Therefore, RSPA is incorporating
by reference NFPA 59A section 2-3.4 for mobile and temporary LNG
facilities in this direct final rule. Operators will no longer need a
waiver from Part 193 requirements for mobile facilities if they comply
with section 2-3.4 of NFPA 59A. This will reduce the burden on the
industry and state and federal governments without compromising safety.
Section 193.2057 Thermal Radiation Protection
RSPA is amending Section 193.2057, ``Thermal radiation
protection'', by deleting the method prescribed and replacing it with a
method based on the ``LNGFIRE'' program model developed by the Gas
Research Institute (GRI). RSPA is amending this section in response to
an American Gas Association (AGA) petition dated October 14, 1992.
According to the AGA petition, the current method is a simple
geometrical method with assumptions of flame radiant properties for
computing the radiation from burning vapor above a concentric pool.
Flame radiant properties were rationalized to provide results that
agree with early experimental results for the lowest level of radiant
exposures. The current method also assumes an idealized tilted
cylindrical flame. Experimental data shows that the current method
underestimates exclusion distances for large pool fires, such as those
that could occur in a tank dike, and overestimates exclusion distances
for small and high ratio length-to-width rectangular fires that could
occur in pipe impoundments.
AGA states that since 1982 GRI has funded a series of research
projects dealing with LNG pool fire radiation. This research has
culminated in a model which more accurately reflects experimental data.
The research has also produced a personal computer based program called
``LNGFIRE.'' This computer model has numerous advantages over the
current method, including the ability to account for a wide variety of
containments. The resulting computer program is easy to use and is in
the public domain. The results of the model and the ``LNGFIRE'' program
correlate very well with experimental results from the numerous
[[Page 8403]]
pool fire tests conducted during the last 15 years.
AGA further explains that the ``LNGFIRE'' program and model
effectively take into account wind speed, relative humidity and
asymmetrical pool configuration. One unique feature in the ``LNGFIRE''
program model is the effect called wind drag. This is the tendency of
the wind to move the base of the flame down-wind from the pool. The
``LNGFIRE'' program also calculates the heat output of the fire based
on the heating value, density and boiling temperature of the LNG.
Although average default properties are included in the program, the
properties of unusually heavy or light LNG can be substituted to
reflect the product used at a particular facility.
RSPA agrees with the AGA's rationale and is replacing the current
thermal radiation protection method with the method based on the
``LNGFIRE'' program model.
Section 193.2059 Flammable Vapor-Gas Dispersion Protection
RSPA is amending section 193.2059, ``Flammable vapor-gas dispersion
protection,'' by deleting the prescribed method based on the
mathematical model in Appendix B of the AGA's 1974 report, ``Evaluation
of LNG Vapor Control Methods,'' also referred to as the Gaussian Line
Source (GLS) model, and replacing it with the ``DEGADIS'' dense gas
dispersion model. RSPA is amending this section in response to the
American Gas Association (AGA) petition dated October 14, 1992.
According to the AGA petition, the dispersion models available at
the time the current federal regulation was issued were limited. Based
on the limited vapor dispersion data available in 1980, DOT provided
for use of the GLS dispersion model as the method for calculating LNG
vapor-gas dispersion siting standards. The GLS dispersion model does
not account for important LNG vapor dispersion phenomena, including
gravity spreading, negative or positive buoyancy effects on air
entrainment, surface-to-cloud heat transfer, or phase change energy
effects associated with air humidity.
AGA states that under GRI sponsorship beginning in 1982, extensive
vapor dispersion experimental and analytical work has been conducted.
The DEGADIS dispersion model, developed for GRI and the U.S. Coast
Guard and recently modified (to allow application to elevated jet
releases) for the U.S. Environmental Protection Agency (EPA), accounts
for effects described above and can be run on a personal computer.
AGA further explains that the DEGADIS model has been shown to be
consistent with a wide range of laboratory and field test data for
dense gas releases on a flat surface with dispersion over unobstructed
flat terrain. Comparison of DEGADIS model predictions with data
obtained from pertinent vapor dispersion field tests has been reviewed.
To provide direct comparison with the GLS model prescribed in 49 CFR
193.2059, the maximum predicted distance to 2.5% methane concentration
was determined for 324 LNG release scenarios with the DEGADIS and GLS
models. DEGADIS generally predicted the longer distances to the 2.5%
methane concentration level than the GLS model for ``B'' atmospheric
stability and shorter distances than the GLS model for ``F'' stability.
AGA states that the recommendation for specification of a surface
roughness factor of 3 cm in DEGADIS presumes the terrain upwind of the
LNG release to be covered with short (order 10 cm) grass. The value of
this surface roughness factor is recommended for normal usage to
provide consistency with the implicit assignment of 3 cm surface
roughness factor in the application of the Guassian model currently
prescribed.
The theoretical and experimental basis for the DEGADIS model are
fully reviewed in GRI Report No. 89/0242 and its applicability to LNG
vapor dispersion prediction has been considered.
The results given in the GRI report indicate that the DEGADIS model
is superior both in dispersion phenomena and performance to the GLS
model promulgated in 49 CFR 193.2059 for LNG vapor dispersion
simulation. Availability in IBM-PC formats provides for wide use of the
DEGADIS model. The DEGADIS model has been accepted and used by federal
agencies such as the Federal Emergency Management Administration
(FEMA), the National Oceanic and Atmospheric Administration (NOAA),
EPA, and the U.S. Coast Guard for dense gas vapor dispersion analysis.
It has also been incorporated in the ALOHA (Area Location of Hazardous
Atmospheres) model. ALOHA is designed for on-site use at accidental
releases for emergency response planning purposes. The South Coast Air
Quality Management District of California has also accepted the use of
the DEGADIS model.
Since the DEGADIS model is in the public domain, is recognized by
other federal and state agencies, and provides significantly more
realistic determination of vapor exclusion distances than the GLS model
currently in 49 CFR 193.2059, RSPA is adopting the DEGADIS model.
Rulemaking Analysis and Notices
Executive Order 12866 and DOT Regulatory Policies and Procedures
This rule is not considered to be a significant regulatory action
under section 3(f) of Executive Order 12866, and is not considered
significant under DOT Regulatory Policies and Procedures (44 FR 11034;
February 26, 1979).
This rule amends LNG regulations to include requirements for mobile
and temporary facilities. This rule replaces the current method
prescribed for ``Thermal Radiation Protection'' with the ``LNGFIRE''
program model. In addition, this rule replaces the current method
prescribed for ``Flammable vapor-gas dispersion protection'' with the
``DEGADIS'' dense gas dispersion model. This is consistent with the
President's goal of regulatory reinvention and improvement of customer
service to the American people. There is no additional cost to comply
with this rule. These changes do not warrant preparation of a
Regulatory Evaluation.
Executive Order 12612
This action has been analyzed under the criteria of Executive Order
12612 (52 FR 41685; October 30,1987) and does not have sufficient
federalism impacts to warrant the preparation of a Federalism
Assessment.
Regulatory Flexibility Act
Based on the facts available concerning the impact of this rule, I
certify under section 606 of the Regulatory Flexibility Act that it
does not have a significant impact on a substantial number of small
entities.
Paperwork Reduction Act
This rule does not modify the paperwork burden that LNG operators
already have. Therefore, a paperwork evaluation is unnecessary.
List of Subjects in 49 CFR Part 193
Fire prevention, Incorporation by reference, Pipeline safety,
Reporting and recordkeeping requirements, Security measures.
In consideration of the foregoing, RSPA amends Part 193 of title 49
of the Code of Federal Regulations as follows:
PART 193--[AMENDED]
1. The authority citation for Part 193 continues to read as
follows:
Authority: 49 U.S.C. 5103, 60103, 60104, 60108, 60109, 60111,
60112, 60118; and 49 CFR 1.53.
[[Page 8404]]
2. Part 193 is amended by adding Sec. 193.2019 to subpart A to read
as follows:
Sec. 193.2019 Mobile and temporary LNG facilities.
Mobile and temporary LNG facilities for peakshaving application,
for service maintenance during gas pipeline systems repair/alteration,
or for other short term applications need not meet the requirements of
this part if the facilities are in compliance with section 2-3.4 of
NFPA 59A (1996 edition).
3. Section 193.2057 is amended by revising paragraphs (b) and
(c)(1) to read as follows:
Sec. 193.2057 Thermal radiation protection.
* * * * *
(b) Measurement. The exclusion distance ``d'' is the horizontal
distance measured from the impoundment area to the target where the
following apply:
(1) The maximum calculated exclusion distance for each thermal flux
level shall be used for that exposure (offsite target) in paragraph (d)
of this section.
(2) The wind speed producing the maximum exclusion distances shall
be used except for wind speeds that occur less than 5 percent of the
time based on recorded data for the area.
(3) The ambient temperature and relative humidity that produce the
maximum exclusion distance shall be used except that values that occur
less than 5 percent of the time based on recorded data for the area
shall not be used.
(4) Properties of LNG with the highest anticipated heating value
shall be used.
(5) The height of the flame base should be that of any dike or
containment in relation to the horizontal reference plane. The height
of the target shall be in relation to the same reference plane.
(c) * * *
(1) The method of calculating the exclusion distances for levels of
radiant exposure listed in paragraph (d) of this section shall be the
method described in Gas Research Institute report GRI-89/0176 and also
available as the ``LNGFIRE'' computer program from GRI.
* * * * *
4. The ``Impoundment & Topography Elevation Profile'' diagram
following Sec. 193.2057(b) of this section is removed.
5. Section 193.2059 is amended by revising paragraphs (c)
introductory text and (d)(1)(ii) and adding paragraph (c)(4), to read
as follows:
Sec. 193.2059 Flammable vapor-gas dispersion protection.
* * * * *
(c) Computing dispersion distance. A minimum dispersion distance
must be computed for the impounding system. If grading and drainage are
used under Sec. 193.2149(b), operators must comply with the
requirements of this section by assuming the space needed for drainage
and collection of spilled liquid in an impounding system. Dispersion
distances must be determined in accordance with the following
dispersion parameters, using the ``DEGADIS'' model described in Gas
Research Institute report No. GRI 89/0242 titled ``LNG Vapor Dispersion
Predication with the DEGADIS Dense Gas Dispersion Model'', or a model
for vapor dispersion which meets the requirements of
Sec. 193.2057(c)(2)(ii) through (iv):
* * * * *
(4) A surface roughness factor of 3 cm shall be used. Higher values
for the roughness factor may be used if it can be shown that the
terrain both upwind and downwind of the vapor cloud has dense
vegetation and that the vapor cloud height is more than ten times the
height of the obstacles encountered by the vapor cloud.
(d) * * *
(1) * * *
(ii) In determining variations in the vaporization rate due to
surface contact, the time necessary to wet 100 percent of the
impounding floor area shall be determined by equation C-9 in the 1974
AGA report titled ``Evaluation of LNG Vapor Control Methods,'' or by
using an equivalent personal computer program based on equation C-9 or
by an alternative model which meets the requirements of
Sec. 193.2057(c)(2)(ii) through (iv).
* * * * *
6. Appendix A to Part 193 is amended in subsection I. by revising
the entries E., F., G., and H. and adding an entry I., and amended in
subsection II. by redesignating entries F. and G. as entries G. and H.
and adding a new entry F. to read as follows:
Appendix A to Part 193--Incorporation by Reference
I. List of Organizations and Addresses
* * * * *
E. American Society of Civil Engineers (ASCE), 345 East 47th
Street, New York, NY 10017-2398.
F. American Society of Mechanical Engineers (ASME), United
Engineering Center, 345 East 47th Street, New York, NY 10017.
G. Gas Research Institute (GRI), 8600 West Bryn Mawr Ave,
Chicago, IL 60631.
H. International Conference of Building Officials, 5360 South
Workman Mill Road, Whittier, CA 90601.
I. National Fire Protection Association (NFPA), 1 Batterymarch
Park, P.O.Box 9101, Quincy, MA 02269-9101.
II. Documents Incorporated by Reference. (Numbers in Parentheses
Indicate Applicable Editions)
* * * * *
F. Gas Research Institute (GRI):
1. GRI-89/0176 ``LNGFIRE: A Thermal Radiation Model for LNG
Fires'' (June 29, 1990).
2. GRI-89/0242 ``LNG Vapor Dispersion Prediction with the
DEGADIS Dense Gas Dispersion Model'' (April 1988-July 1990).
* * * * *
Issued in Washington, D.C. on January 23, 1997.
Kelley S. Coyner,
Deputy Administrator.
[FR Doc. 97-4614 Filed 2-24-97; 8:45 am]
BILLING CODE 4910-60-P
