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Modelling Pool Fire Hazards from Large-scale Liquefied Natural Gas Spills
theory, differ in terms of the physical values of certain parameters (e.g. the insight into the physical phenomena that occur within a large pool fire and
flame SEP) or the correlations used to define the geometry of the solid determine the overall fire behaviour. For example, measuring the SEP and
flame cylinder (e.g. the flame height). smoke shielding from a 100m-diameter pool fire will provide an additional
data point for the existing correlations, but is unlikely to explain why the
When the effects of the principal solid flame model parameters on thermal measured values were obtained. These questions are generally better
hazard distances are evaluated, a large variability in the predicted hazards answered by smaller-scale controlled experiments that can isolate specific
becomes apparent. The results show that parameters such as flame height, phenomena and be run in a controlled and repeatable manner.
SEP and smoke shielding have a significant impact on the predicted
outcomes, particularly as the pool diameter grows beyond 100m. The main Until new data are obtained, anyone performing a consequence
reason for the large variability of the results is the lack of experimental data analysis for a large-scale LNG pool fire should exercise caution in
at scales comparable to those predicted for large-scale LNG spills on water. selecting the numerical values of the parameters to be entered into the
While several large-scale LNG pool fire tests, with pool diameters up to solid flame model, including performing sensitivity studies on the effect
approximately 100m, are planned and may help to reduce the uncertainty in of the critical parameters identified in this analysis (SEP, flame height
the models, it is not clear whether these tests will provide the necessary and smoke shielding). ■
1. NFPA 59A, Table 5.2.3.2, 2006. Appendix K, 24 October 2006. Hazard Assessment, Fire Safety J, 1987;12:89–96.
2. ABS Consulting, Consequence Assessment Methods for 7. Government Accountability Office, Maritime Security: 13. Thomas PH, The size of flames from natural fires, Proc
Incidents Involving Releases from Liquefied Natural Gas Opportunities Exist to Further Clarify the Consequences of a Combust Inst, 1963;9:844–9.
Carriers, for the Federal Energy Regulatory Commission, Liquefied Natural Gas Tanker Spill, GAO-07-840T, 2007. 14. Heskestad G, Luminous Heights of Turbulent Diffusion
GEMS 1288209, 2004;29–35. 8. Raj PK, Large hydrocarbon fuel pool fires: Physical Flames, Fire Safety J, 1983;5:103–8.
3. Gas Research Institute, LNGFIRE3: A Thermal Radiation characteristics and thermal emission variations with height, 15. McCaffrey B, Chapter 2.1: Flame Height. In: DiNenno P,
Model for LNG Fires, GRI-04/0032, 2004. Journal of Hazardous Materials, 2007;140:280–92. SFPE Handbook of Fire Protection Engineering, 2nd Edition, Quincy,
4. Sandia National Laboratory, Guidance on risk analysis and 9. FERC, Notice of availability of detailed computations for the MA: National Fire Protection Association, 1995.
safety implications of a large liquefied natural gas (LNG) spill consequence assessment methods for incidents involving 16. Pritchard MJ, Binding TM, FIRE2: A New Approach for
over water, SAND2004-6258, 2005. releases from liquefied natural gas carriers, Docket No. A04- Predicting Thermal Radiation Levels from Hydrocarbon Pool
5. Beyler CL, Chapter 3–11: Fire Hazard Calculations for Large 6-000, 29 June 2004. Fires, I Chem E Symposium Series, 1992;130:491–505.
Open Hydrocarbon Fires. In: DiNenno P (ed.), SFPE Handbook of 10. American Gas Association, LNG Safety Research Program, 17. Sandia National Laboratory, Breach and Safety Analysis of
Fire Protection Engineering, 3rd Edition, Quincy, MA: National Fire Report IS 3-1, 1974. Spills over Water from Large Liquefied Natural Gas Carriers,
Protection Association, 2002. 11. Moorhouse J, Scaling criteria for pool fires derived from SAND2008-3153, 2008.
6. Northeast Gateway, Final Environmental Impact Statement, large-scale experiments, J I Chem Sym, 1982;71:165–79.
DOT Docket No. USCG-2005-22219, Chapter 5 and 12. Mudan KS, Geometric View Factors for Thermal Radiation
Gas Leak Reduction Project Wins Health, Safety and Environment Award
The health, safety and environment (HSE) award from the Mr Vold points out that installations on the NCS were clearly
Petroleum Safety Authority Norway (PSA) has been presented to experiencing too many gas leaks when the project began.
the Norwegian Oil Industry Association (OLF) on behalf of the Targets were therefore ambitious from the start. The first was to
industry for its gas leak reduction project. halve the number of leaks from 40 in 2003 to fewer than 20 in
2005. That goal was reached, and the project switched its
This programme has helped to reduce the number of gas leaks attention to halving the number again, to less than 10 by the
on the Norwegian continental shelf (NCS) from 40 in 2003 to 10 end of 2008. That target was hit in 2007 – a year early.
in 2007.
An analysis of the causes of the many gas leaks conducted in the
The gas leak reduction project offers a very good example of the first phase of the project found that the industry had to boost
way in which results can be achieved when the oil and gas industry employee expertise and review equipment to meet its targets.
collaborates purposefully, according to Per Terje Vold, Chief Planning, leadership and follow-up of the project have been
Executive of the OLF. Working for a constant reduction in gas leaks provided by the OLF, notes Mr Vold. “We have functioned as a
is one of the most important measures that can reduce the total facilitator and hub for the work, but the goals would never have
level of risk in our business. been reached without a big commitment in the project group and
among operators of pressurised equipment on the installations.”
Since its launch in 2003, the gas leak reduction project has received
great attention from the industry. All of the operators have seen that The results have been achieved in the companies through good
this work is very important in reducing the risk level. Mr Vold notes co-operation between management and employees. With the
that the project has achieved results because everyone concerned has industry very keen to ensure that the good results continue, efforts
pulled in the same direction, from people working with pressurised will be devoted in the future to boosting management focus and
equipment offshore to company management. Today’s project expertise on pressurised equipment. “The project will continue
manager, Dan Petter Berg at StatoilHydro, earlier project managers with undiminished vigour,” says Mr Vold. Cutting the number of
and others who have been involved from the industry have done a gas leaks makes a key contribution to the work of further
fantastic job, which has been reflected in the results. reducing the total level of risk on the NCS. ■
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EXPLORATION & PRODUCTION – OIL & GAS REVIEW 2008 – VOLUME 6 ISSUE II
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