Risk Analysis for LNG Terminal SitingRisk Analysis for LNG Terminal Siting Changes in NFPA 59A & Future RegulationsChanges in NFPA 59A & Future Regulations

Phani Raj , TMSPhani Raj , TMS

Theodore Lemoff, NFPATheodore Lemoff, NFPA

2008 International Symposium at the 2008 International Symposium at the MKOPSC MKOPSC

College Station, TX 77843College Station, TX 778432929thth October 2008October 2008

Current Approach to LNG facility sitingCurrent Approach to LNG facility siting

NFPA 59A and 49CFR, part 193NFPA 59A and 49CFR, part 193

Approach is very prescriptiveApproach is very prescriptive

Only three types of accidents and sizes Only three types of accidents and sizes specified;specified;

Pool fire radiative heat and vapor dispersion Pool fire radiative heat and vapor dispersion

Passive protection acceptable (with AHJPassive protection acceptable (with AHJ’’s s consent) for mitigating vapor hazards but not consent) for mitigating vapor hazards but not fire hazardsfire hazards

No mechanism for local inputNo mechanism for local inputNo consideration of other sources of ignitionNo consideration of other sources of ignition

New Risk Based (alternative) LNG Standard New Risk Based (alternative) LNG Standard in NFPA 59A in NFPA 59A

The new risk based analysis requires: The new risk based analysis requires:

Designing and locating LNG plants in areas Designing and locating LNG plants in areas to not pose unacceptable risks to people, to not pose unacceptable risks to people, installations or property. installations or property.

Establishing an acceptable risk profile. Establishing an acceptable risk profile.

Reassessing the level of risks when the LNG Reassessing the level of risks when the LNG plant is modified or other conditions changeplant is modified or other conditions change

Assure that the risk level is not increasedAssure that the risk level is not increased

Conducting reassessments at least every Conducting reassessments at least every three years or as required by authorities. three years or as required by authorities.

Risk based approachRisk based approach

All types of failures and accidental conditions All types of failures and accidental conditions are consideredare considered

More importantly the release scenarios are More importantly the release scenarios are weighted by the likelihood of occurrenceweighted by the likelihood of occurrence

Local conditions and occupancies are taken Local conditions and occupancies are taken into account (including densities) into account (including densities)

Alternative mitigation approaches can be Alternative mitigation approaches can be considered and their effects evaluatedconsidered and their effects evaluated

Local authorities can participate in decision Local authorities can participate in decision makingmaking

Risk Risk –– ProcessProcess

Questions:Questions:

RiskRisk

Total Risk:Total Risk:

Individual Individual Risk:Risk:

Societal Societal

Risk:Risk:

1. What can go wrong?1. What can go wrong?2. How likely is it?2. How likely is it?3. What are the impacts?3. What are the impacts?

[Annual hazardous event occurrence] x [Annual hazardous event occurrence] x [the consequence magnitude of the event][the consequence magnitude of the event]

Risk of involuntary exposure of a typical Risk of involuntary exposure of a typical individual to a specific level of hazardindividual to a specific level of hazard

Risk of involuntary exposure of a typical Risk of involuntary exposure of a typical individual to a specific level of hazardindividual to a specific level of hazard

Risk to people in a specified populationRisk to people in a specified populationexposed to specific hazardsexposed to specific hazards

Salient Features of the Risk Salient Features of the Risk Assessment in NFPA 59AAssessment in NFPA 59A

Consideration of a spectrum of LNG release Consideration of a spectrum of LNG release scenarios scenarios

Obtained from systematic analyses (i.e., HAZOP)Obtained from systematic analyses (i.e., HAZOP)

Including the release scenarios in Table 5.3.37.Including the release scenarios in Table 5.3.37.

Evaluation of the annual probabilities of Evaluation of the annual probabilities of occurrence of release scenarios,occurrence of release scenarios,

Including the conditional probabilities of different Including the conditional probabilities of different weather and local conditions, and different types weather and local conditions, and different types of LNG behavior.of LNG behavior.

Salient Features of the Risk Salient Features of the Risk Assessment in NFPA 59AAssessment in NFPA 59A

Characterization of an event (with conditional Characterization of an event (with conditional probability subprobability sub--events) into a probability class events) into a probability class based on published class listings (Table E.4(a))based on published class listings (Table E.4(a))

Determination of the consequence categories Determination of the consequence categories according to the number of injuries (Table according to the number of injuries (Table E.4(b)). E.4(b)).

The criteria for consequences, whether exposed to a The criteria for consequences, whether exposed to a fire or to a flammable vapor cloud are the same as fire or to a flammable vapor cloud are the same as in the prescriptive section (Table 5.3.3.2 & in the prescriptive section (Table 5.3.3.2 & §§5.3.3.6).5.3.3.6).

Mapping the frequencyMapping the frequency--consequence pair for consequence pair for each release event into an acceptability each release event into an acceptability matrix, indicated as Table E.4(c).matrix, indicated as Table E.4(c).

Tables from Tables from 2009 edition of NFPA 59A2009 edition of NFPA 59A

88

Tables from Tables from 2009 edition of NFPA 59A2009 edition of NFPA 59A

99

Individual Risk MeasuresIndividual Risk Measures

Individual Risk Criteria Individual Risk Criteria

Societal Risk CriteriaSocietal Risk Criteria

1212

Calculation of individual riskCalculation of individual risk

Criteria for Risk AcceptanceCriteria for Risk Acceptance in EU Countriesin EU Countries

Allowable developments around a LNG Allowable developments around a LNG facilityfacility

An example LNG FacilityAn example LNG Facility

Results: Individual RiskResults: Individual Risk

ConclusionsConclusions

Risk analysis (RA) considers a range of Risk analysis (RA) considers a range of possible release scenarios and their effects possible release scenarios and their effects

RA is a balanced approach to determining RA is a balanced approach to determining the real impact of a proposed or current the real impact of a proposed or current facility.facility.

The RA procedure can be used to assess The RA procedure can be used to assess the effectiveness of mitigation approaches.the effectiveness of mitigation approaches.

RA has been successfully used in other RA has been successfully used in other countries (particularly in Europe) for countries (particularly in Europe) for chemical and hazardous material facilities.chemical and hazardous material facilities.

Decisions can be made on the basis of Decisions can be made on the basis of comparative risks rather than on y comparative risks rather than on y improbable events (as are done now).improbable events (as are done now).

Thank you for your attention

Questions?