[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]
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