Characterizing Risk from Pipelines CarryingFlammable and Toxic Materials

摘要

Pipelines transport a wide range of toxic and flammable gases and liquids in closeproximity to population centers. The most familiar examples are natural gas transmissionlines that can be 3 feet in diameter and operate at pressures of 1000 pounds per squareinch. Lines carrying gasoline, jet fuel, crude oil and liquefied petroleum gas (LPG) canalso pose risks to individuals and as well as[W1] structures. It is less well known thatpipelines also carry other hazardous chemicals such ammonia and carbon dioxide. Incontrast to fixed facilities, the distance to potential populated areas can be much smallerfor a pipeline, so that the precision and accuracy of the analysis technique can have alarge effect on the projected risk. In addition, a pipeline risk assessment needs to addressthe probability of a breach at various locations along the route. Specialized methods arerequired to properly quantify the risk and consequences of a pipeline rupture, whether itis due to an accident or malicious intent. The specific hazards to be addressed can varywidely depending on the substance being transported. For example, the rupture of anatural gas transmission line can cause a dangerous radiant heat flux at substantialdistances. Due to its high vapor pressure, a gasoline spill can represent an even greaterhazard because flammable vapor can move beyond the margins of the liquid to encounterpotential sources of ignition. In other instances, the liquid itself can also migratesignificant distances beyond the point of the release. Because it disperses as a heavierthan-air gas, a release of LPG from a pipeline rupture poses both a vapor cloud explosionand radiant heat hazard. This paper describes a general methodology to address bothindividual and population-risk from pipelines and provides examples of the consequencesand risks of pipeline failures for specific flammable and toxic materials.