Consequence Assessment Methods for Incidents Involving Releases from Liquefied Natural Gas Carriers
Prepared by: ABSG Consulting Inc.
Liquefied natural gas (LNG) has been transported by sea since 1959 in specially designed LNG carriers. These vessels have a remarkable safety record and provide an essential link in the movement of LNG from production locations to consumer locations. However, stakeholders recognize that there are possibilities for some serious incidents involving LNG carriers, particularly in light of increased awareness and concern about potential terrorist actions.
The Federal Energy Regulatory Commission (FERC) sponsored this study with the goal of identifying appropriate consequence analysis methods for estimating flammable vapor and thermal radiation hazard distances for potential LNG vessel cargo releases during transit and while at berth.
This work considers the flammable vapor and thermal radiation hazards created by unconfined LNG spills on water resulting from an LNG cargo release. This includes review of literature on experimental LNG spills and on consequence assessment methodologies that are applicable to modeling of incidents involving LNG spills on water.
The key modeling issues addressed in this report are:
- Rate of release of LNG from a ship
- Spread of an unconfined pool on water
- Vapor generation for unconfined spills on water
- Thermal radiation from pool fires on water
- Distance for flammable vapor dispersion following spills on water
- Rapid phase transitions (RPTs)
- Effects of thermal radiation on people and structures