{"operation":"document","citation":"PI-10-0005","title":"Fulbright & Jaworski L.L.P. — Pipeline Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"2010-07-16","effective_on":null,"summary":"PI-10-0005 response to Fulbright & Jaworski L.L.P. concerning 193.2059.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-10-0005.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-10-0005.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-10-0005","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/Pipeline/2010/PI-10-0005.pdf","body":"<<<PAGE 1>>>\n\nu.s. Department\nof Transportation\nPipeline and Hazardous Materials\nSafety Administration\n1200 New Jersey Ave .. SE\nWashington, DC 20590\n'JUL 1 62010\nCERTIFIED MAIL - RETURN RECEIPT REQUESTED [7009 1410000024722674]\nMs. Lisa M. Tonery\nFulbright & Jaworski L.L.P.\n666 Fifth Avenue, 31 st Floor\nNew York, NY 10103-3198\nRE: Request for Written Interpretation on the Applicability of 49 C.F.R. Part 193 to\nProposed LNG Import Terminal in Robbinston, Maine\nDear Ms. Tonery:\nAs counsel for Downeast LNG, Inc. (Downeast or the Company), you have asked for a written\ninterpretation on two questions related to your client's proposal to build a liquefied natural gas\n(LNG) import terminal in the town of Robbinston, Maine (Robbinston LNG Import Terminal or\nthe Terminal). Specifically, you have asked whether Downeast may use its alternative source\nterm model (DLNG Source Term Model) to comply with the vapor-gas exclusion zone\nrequirements in 49 C.F .R. § 193.2059 . You have also asked whether the Company must\nexamine the effects of jetting and flashing to comply with those same requirements.\nUnder the conditions described in this letter, Downeast may use the DLNG Source Term Model\nto calculate the vapor-gas exclusion zone for the sumps at the Robbinston LNG Import Terminal.\nThe Company must also examine the effects of jetting and flashing in siting appropriate facilities\nat the Terminal, including pressurized piping or equipment, to comply with our vapor-gas\ndispersion exclusion zone requirements.\nQuestion 1\nThe Pipeline and Hazardous Materials Safety Administration (PHMSA) issues federal safety\nstandards for siting LNG facilities.! Those regulations require that an operator or governmental\nauthority control the activities that occur within a specified distance around the facilities at an\nLNG plant, to protect the public from unsafe levels of thermal radiation and flammable vapor-\ngas dispersion in the event of an accident. Certain mathematical models and other parameters\nmust be used to calculate the dimensions of these \"exclusion zones.\"\nIn the case of vapor-gas dispersion, two different computational models are already authorized\nfor use by regulation: (1) the DEGADIS Dense Gas Dispersion Model (DEGADIS), a model\ndeveloped by the U.S. Coast Guard and Gas Research Institute (GR!) to simulate the downwind\nI Pipeline Safety Act of 1979, Pub. L. No. 96-129, § 152, 93 Stat. 989 (1979) (currently codified at 49 U.S.C.\n§ 60103(a)).\n1\n\n<<<PAGE 2>>>\n\ndispersion of dense gases in the atmosphere, and (2) FEM3A, another dispersion model designed\n\"to account for additional cloud dilution which may be caused by the complex flow patterns\ninduced by tank and dike structure.,,2\nDowneast intends to calculate the vapor-gas dispersion exclusion zone for the Robbinston LNG\nImport Terminal with DEGADIS, an integral model that requires the user to input a \"source\nterm.\" The source term is designed to simulate the physical phenomena that occur immediately\nafter an LNG release, but prior to atmospheric dispersion.3\nYou have asked whether the Company may use a new source term model, the DLNG Source\nTerm Model, to perform the exclusion zone analysis for the sumps at the Terminal. You state\nthat this new model uses conservative assumptions for the effects of pool spreading, vapor\nproduction, and vapor retention. In your opinion, that makes it suitable for use with DEGADIS\nunder our regulations.\nThe source term used as the input for DEGADIS must have a suitable basis to comply with our\nSiting Requirements. \"Otherwise, a user could select whatever source term is likely to produce\nthe most favorable outcome, e.g., the smallest or largest possible exclusion zone, or even at\nrandom.,,4 Such a result would not be consistent with the limitations of DEGADIS or our\nstatutory obligation to protect the public from the hazards associated with an LNG plant. For\nthese reasons, the utmost care must also be exercised in evaluating the suitability of any such\nmodel, a task that involves \"making predictions, within [PHMSA' s] area of special expertise. ,,5\nWe further note that the proponent of an alternative source term model previously had to petition\nfor, and receive, the Administrator's approval to use that model to comply with our vapor-gas\ndispersion exclusion zone requirements.6 However, our predecessor agency repealed that\nrequirement in a March 2000 final rule.7 Consequently, the Administrator's approval is no\n249 C.F.R. § 193.2059 (2010). The Administrator may also approve the use ofaltemative vapor-gas dispersion\nmodels that \"take into account the same physical factors and have been validated by experimental test data.\" 49\nC.F.R. §§ 193.2057(a), 193.2059(a); 49 C.F.R. § 190.1 I (2010) (authorizing the submission of petition for finding\nor approval with the Administrator).\n3 Ivings, et a!., LNG Source Term Models for Hazard Analysis: A review of the State-of-the-Art and an\nApproach to Model Assessment, p. vi (Mar. 2009) (on file with PHMSA).\n4 In the Matter ofMssrs. Keppel and Miozza, PHMSA Interp. (July 7, 2010) (to be available at\nwww.phmsa.dot.gov).\n5 Baltimore Gas and Electric Company v. Natural Resources Defense Council, 462 U.S. 87, 103 (1983); see\nWisconsin Electric Power Company v. Costle, 715 F.2d 323, 329 (7th Cir. 1983) (upholding EPA's use of a\nparticular dispersion model and stating that its \"choice to rely on an air quality model is a policy judgment deserving\ngreat deference.\").\n6 Liquefied Natural Gas Facilities; New Federal Safety Standards, 45 Fed. Reg. 9 I 84 (Feb. II, 1980); Liquefied\nNatural Gas Facilities; Reconsideration of Safety Standards for Siting, Design, and Construction, 45 Fed. Reg.\n57402,57418 (Aug. 28, 1980) (denying, in part, and granting, in part, a petition for reconsideration); see In the\nMatter of Energy Terminal Services Corporation, PHMSA Interp. 82-05-28 (May 28, 1982); In the Matter of Mr.\nGeorge H. Lawrence, President, American Gas Association, PHMSA Interp. 83-06-29 (June 29, 1983); see also\nLiquefied Natural Gas Regulations-Miscellaneous Amendments, 62 Fed. Reg. 8402, 8404 (Feb. 25, 1997)\n(amending 49 C.F.R. § I93.2059(d)(l)(ii)).\n7 Pipeline Safety: Incorporation of Standard NFPA 59A in the Liquefied Natural Gas Regulations 65 Fed. Reg.\n10950, 10953 (March 1,2000).\n2\n\n<<<PAGE 3>>>\n\nlonger an absolute prere~uisite to using an alternative source term model with DEGADIS under\nour Siting Requirements.\nIn our opinion, the DLNG Source Term Model can be used with DEGADIS to calculate the\nvapor-gas dispersion exclusion zones for the sumps at the Robbinston LNG Import Terminal.\nDowneast has demonstrated, through the use of a parametric analysis, that an instantaneous pool\nspreading scenario across these particular sump floors will produce the longest flammable vapor-\ngas cloud. The Company has also shown that its heat transfer methodology is appropriate. As\nconfirmed in the documents submitted with your letter, that methodology \"assum[ es] perfect\nthermal contact between [the] pool and [the] ground, and only vertical temperature gradients in\nthe ground,\" and the conduction is modeled \"by the one-dimensional Fourier conduction\nequation in the ground, with an initial state where the ground is uniformly at ambient\ntemperature, and assumes the boiling temperature of LNG as soon as the spreading pool reaches\"\nthe sump floor. Finally, the model conservatively assumes that none of the produced vapors is\nretained by the sump walls.\nThese conservative assumptions provide the model with a suitable basis for use in this particular\napplication. Accordingly, we conclude that the DLNG Source Term Model can be used with\nDEGADIS to calculate the vapor-gas dispersion exclusion zones for the sumps at the Robbinston\nLN G Import Terminal. 9\nQuestion 2\nThe phenomena known as jetting and flashing can occur if pressurized piping or equipment fails.\nJetting can cause released LNG to propel beyond an impoundment system, or result in\nfragmentation and formation of aerosols. It can also erode earthen dikes, expose equipment to\ncryogenic liquids, or project LNG or its vapors onto adjacent properties. Flashing is the\ninstantaneous vaporization of released LNG due to exposure ambient pressure and temperature.\nLike jetting, it can cause fragmentation and formation of aerosols and project vapors onto\nadjacent properties. Understanding the effect of these phenomena is important to public safety,\nas they can create hazards (e.g., cascading failures, the loss of containment, and the\ninstantaneous formation of a vapor-gas cloud) that are capable of affecting offsite properties and\nactivities.\nYou state that Downeast has not considered jetting and flashing in siting the Robbinston LNG\nImport Terminal, because the \"Part 193 Subpart B LNG Requirements do not speak to either\nflashing or jetting and flammable vapor production rate in the event of an LNG leak.\" You have\nasked PHMSA for an opinion to that effect, namely, that \"[j]etting and flashing are not to be\nconsidered with respect to the exclusion zone analysis of 49 CFR Section 193.2059.\" Contrary\nto your position, we conclude that these phenomena should be considered in appropriate cases.\n8 As in the case of Downeast, those seeking to use an alternative source term model with DEGADIS may obtain an\ninterpretation from this agency on the suitability of such a model. 49 C.F.R. § 190.11 (2010).\n9 Our opinion on the suitability of the DLNG Source Term Model only applies to the sumps and does not address the\nadequacy of the exclusion zone analyses performed for any other area at the Robbinston LNG Import Terminal.\n3\n\n<<<PAGE 4>>>\n\nThe source tenn model used as the input for DEGADIS must have a suitable basis to comply\nwith our vapor-gas exclusion zone requirements. In the case of jetting and flashing, there is no\ndispute that a failure of pressurized piping or equipment may cause LNG to vaporize in the air.\nUsing a source tenn model that ignores that effect (or any other phenomena that has a similar\ninfluence on the discharge, vaporization, or conveyance of LNG) could distort the downwind\ndispersion of vapor gas and compromise the integrity of an operator's exclusion zone analysis.\nSuch a result would not ensure that the siting of an LNG facility occurs in a manner consistent\nwith our statutory obligations. Consequently, a source tenn model should account for the effects\nof jetting and flashing in appropriate cases, including where a design-spill scenario involves a\nfailure of pressurized piping or equipment.\nConsideration of jetting and flashing might also be required outside the confines of an exclusion\nzone analysis. lo For example, steps must be taken to ensure that any released LNG is retained\nwithin the limits of plant property. I That includes \"grad[ing], drain[ing], or provid[ing]\" certain\nareas \"with [an] impoundment\" to reduce \"the possibility of accidental spills and leaks that could\nendanger im;ortant structures, equipment, or adjoining property or that could reach\nwaterways.\" I Similarly, site-specific factors that have a bearing on the safety of plant personnel\nor the surrounding public must be evaluated in siting an LNG facility, and appropriate responsive\nsafety measures must be incorporated into the design or operation of that facility. 13 However, as\nyou did not request an interpretation of these or any other provisions, we simply note in closing\nthat an operator must demonstrate that a new LNG facility complies with our Siting\nRequirements. 14\nConclusion\nDowneast may use the DLNG Source Tenn Model to calculate the vapor-gas exclusion zone for\nthe sumps at the Robbinston LNG Import Tenninal. The Company must also examine the\neffects of jetting and flashing in calculating the vapor-gas dispersion exclusion zone for any\nappropriate LNG facilities, including pressurized piping or equipment, to comply with the Siting\nRequirements in Subpart B of 49 C.F.R. Part 193.\nSincerely,\n~~\nJeffrey D. Wiese\nAssociate Administrator\nfor Pipeline Safety\n10 49 C.F.R. § 193.2051 (2010).\nII 2001 NFPA 59A, 2.1.2.\n12 2001 NFPA 59A, 2.2.1.2.\nJ3 2001 NFPA 59A, 2.1.1(d).\n14 See e.g., 5 U.S.c. § 556(d); Schaffer v. Weast, 546 U.S. 49, 56-57 (2005).\n4\n\n<<<PAGE 5>>>\n\nFULBRIGHT & .JAWORSKI L.L.P.\nA REGISTERED LIMITED l_IABILITY PARTNERSHIP\n666 FIFTH AVENUE. 31ST FLOOR\nNEW YORK. NEW YORK 10103-3198\nWWW.FULBRIGHT.COM\nLISA TONERY\nPARTNER\nL TO N ERy(oJFU LBRIGHT .CO M\nDIRECT DIAL:\nTELEPHONE:\nFACSIMILE:\n( 2 I 2) 3 I 8-3009\n( 2 I 2) 3 I 8-3000\n(2 I 2) 318-3400\nMay 10,2010\nMAY 11 2010\nJetTrey D. Wiese\nAssociate Administrator for Pipeline Safety\nPMHSA\nU. S. Department of Transportation\n1200 New Jersey Avenue, SE\nWashington, DC 20590-0001\nRe: Request fOl' Interpretation of 49 CFR Part 193\nDear Mr. Wiese:\nDowneast LNG, Inc. (Downeast LNG) has an application pending before the Federal\nEnergy Regulatory Commission (FERC) in Docket No. CP07-52-000 for authorization to site,\nconstruct and operate a liquefied natural gas (LNG) impOli tenl1inal and associated natural gas\npipeline in Washington County, Maine. In conjunction with that pending application, pursuant to\n4() CFR Section 190.11(b)(l), we are requesting an interpretation of the Part 193 Subpart B LNG\nFacilities Federal Safety Standards Siting Requirements. Specifically, we seek a written\nintcqJretation conceming 49 CFR Section 193.2059 for the items set tcnih below.\nFlammable Vapor Source Term\nBy way of background, in an efTort to develop LNG dispersion model evaluation tools for\nthe NFPA 59A Committee, the Fire Protection Research Foundation (FPRF) funded research on\nLNG spill source teml modeling and, in March, 2009 its findings were included in a repOli\nentitled \"LNG Source Term Models for Hazard Analysis: A Review of the State-of-the-Art and\nan Approach to Model Assessment\". The report presented a methodology for assessing the\nsuitability of LNG source tenl1 models used in determining pool spread and vaporization. The\nreport concluded that the SOURCE model generally used within the LNG industry, and which\nwas also used by Downeast LNG in its initial detemlination of flammable vapor dispersion\nExclusion Zones, could result in under-prediction of hazard distances in some cases because it\ndoes not accurately represent:\n• Pool spreading and the resulting flammable vapor \"tlashing\", and\n• V apor accumulation within impoundments,\nDowneast LNG has prepared a source tem1 calculation that addresses these specific concems and\nprovides input to the DEGADIS Dense Gas Dispersion Model that is specified in 49 CFR\n193.2059. A copy of the calculation (previously filed with FERC on October 30, 2009) is\n\n<<<PAGE 6>>>\n\nJeffrey D. Wiese\nMay 10,2010\nPage 2\nattached to this letter (see Appendix I, \"Thcrll/a/ Radiation (flld Vapor Dispersioll Ca/cli/ations\nfor [)()',Vlleast LNG\") and the following summarizes how Downeast LNG has addressed the\nparticular concems raised by the FPRF:\nPool Spreading and Flammable Vapor Production\nThe SOURCES pool spreading model on land uses an adaptation of a fairly standard\nmodel for spreading on water. However. it has been known since the mid 1980s to have no\njusti fication for spreading on land I . In order to overcome this limitation, the approach proposed\nby Downeast LNG has considered a range of spreading speeds across the sump floor, including\ninstantaneous spreading to identify the speed that generates the longest ignitable vapor cloud\nusing DEGADIS. In its calculation filed with the FERC on October 30, 2009, Downeast LNG\nstated that the instantaneous spreading scenario is the most conservative since it would result in\nthe longest ignitable vapor cloud. Downeast confil111ed this assumption by parametrically\nvarying the LNG spreading speed to calculate the rate of evaporation over time. A copy of the\nparametric analysis and associated findings is attached to this letter (see Appendix 2, \"Dowllcast\nLNG - Parametric St/l(!1' oj'the Sensitivi(l' oj'the Vapor Dispersion Distallce to the Rate of\n5j)f'('adillg oj'LNG in a SZltlZp\").\nAs the pool spreads, it cools the ground below it. Initially (at least) by far the dominant\nmode of heat transfer to a cryogenic pool spilt on land is conduction from the solid ground\nbelow. As the pool spreads over the area of the sump, the ground beneath it will cool very\nrapidly, and the heat flux into the pool will decrease with time. The FPRF report found the\nSOURCES method of quantifying the rate of evaporation unclear based on an edition of the TNO\nYellow Book which had long been superseded. In the method proposed by Downeast LNG, the\nheat transfer to the spreading contlned pool has been calculated assuming perfect thel111al contact\nbetween pool and ground, and only vertical temperature gradients in the ground. The conduction\nhas been modeled by the one-dimensional Fourier conduction equation in the ground, with an\ninitial state where the ground is unifonnly at ambient temperature, and assumes the boiling\ntemperature of LNG as soon as the spreading pool reaches it. This is considered a good model in\nthe early stages of the spill when rates of evaporation are high according to the FPRF report.\nFlammable Vapor Retention\nThe SOURCES model defines the source of vapor to be precisely zero until the liquid\ndepth, plus the depth of vaporized (but undiluted) LNG, becomes equal to the height of the dike\nwall. This is not credible if there is any wind at all. Flllihennore, air entrainment and mixing\nduring the evaporation process will also dilute the LNG vapors. For these reasons, the calculation\nprepared by Downeast LNG does not take credit for any vapor retention or hold-up within the\nsump. This approach results in an earlier release of vapors at a time when the rate of evaporation\n;'vlodel Assessment Report on SOURCE5 Version 5 revision I. LNG Source Term Models tCll' Hazard Analysis: a\nReview of the State-of-the-Art and an Approach to Model Assessment, Final Report, .. Prepared by: Dr D.M.\nWebber, Dr S.E. Gant. DrMLlvings arrdS.F. Jagger, Health & Safety Laooratury, March lBB(}.\n\n<<<PAGE 7>>>\n\n, '\nJeffrey D. Wiese\nMay 10,2010\nPage 3\nis at its highest and higher than the rate of evaporation when the vapors begin to spill out of\nretention in the SOURCES model. In reality, sump walls do provide some degree of vapor\nretention and hold-up. Therefore, the method used by Downeast LNG results in a rate of vapor\nfonmltion that is larger than would be expected in reality. 2\nJetting and Flashing\nIn the Draft Environmental Impact Statement (DEIS) issued by FERC for the Downeast\nLNG project in May 2009, FERC included a condition that requires Downeast LNG to \"examine\nprovisions to minimize any effects from flashing or jetting on the downward dispersion distance\nof vapor fr0111 a release from pressurized piping at the LNG terminal.'\"\nThe previously referenced FPRF study considered jetting and flashing and its repOli states\nthat a leak from a pressurized pipeline may lead initially to jetting of the liquid, and if the jet is\nunobstructed, a large fraction of the LNG may vaporize in the air before the liquid rains out and\nforms a pool. The FPRF repOli also states that the nature of the jet, and hence the amount of\nvaporization from the jet, will depend upon the ambient temperature, the pressure and\ntemperature of the LNG, the initial velocity of the liquid, the orifice size and shape, the fluid\ntraj cctory, atomization of the liquid spray, and the entrainment rate of fresh air.\nNotably, since the Part 193 Subpart B LNG Siting Requirements do not speak to either\nflashing or jetting and flammable vapor production rate in the event of an LNG leak the\nDO\\vneast LNG application did not specifically address the considerations in its design.\nRequest for Interpretation of 49 CFR Part 193\nDowneast LNG is requesting an interpretation that:\n( 1 ) Use of the foregoing methodology as summarized above and described in greater\ndetail in Appendices 1 and 2 is consistent and in compliance with 49 CFR Section\n193.2059; and\n(2) Jetting and flashing are not to be considered with respect to the exclusion zone\nanalysis of 49 CFR Section 193.2059.\nDowneast LNG respectfully requests that the above-requested guidance be provided at the\nearliest date possible so that the Downeast LNG project may move forward in the FERC\n2 See p. J 4 Model Assessment Report on SOURCES Version S revision 1. Ref No. CE51{)4 iv/A RIHSUSOUR,\n\\' ersion 4 February 2009, in Appendix A of \"LNG Source Term Models for Hazard Analysis: a Review of the\nState-of-the-Art and an Approach to Model Assessment, Final Report, \" Prepared by: Dr D.M. Webber, Dr S.E.\nCiant, Dr M.J. Ivings and S.F. Jagger, Health & Safety Laboratory. March 2009\n3 See Dowrieast LNG DEIS Condition 40 (May 2009)\n\n<<<PAGE 8>>>\n\nJeffrey D. Wiese\nMay 10,2010\nPage 4\npellnitting process. To that end, please feel free to contact the undersigned with any questions\nconceming the foregoing.\nectfully submitted,\n.. ~.\\~~:r'Z;\\\ni a M. T onery (':::J\nAttorncv {or Dml'IIC{{st LNG. file.\nAttachments\ncc: Charles Helm\nKeith Coyle\nTeITY Turpin\nDean Girdis\nArthur Ransome\nHaITi Kytomaa","truncated":false,"body_characters":21050}