The Transportation of Dangerous Goods (TDG) Program develops risk-based safety standards and regulations, provides oversight, and gives expert advice on dangerous goods incidents to promote public safety in the transportation of dangerous goods by all modes of transport in Canada. The Canadian Transport Emergency Centre (CANUTEC) is responsible for delivering emergency response advice 24 hours a day, seven days a week, to anyone with questions or concerns involving the transportation of dangerous goods or emergencies involving dangerous goods. This includes advice on dangerous goods release mitigation strategies, the physical and chemical properties of dangerous goods, as well as protective actions (e.g. recommendations for personal protective equipment (PPE) and evacuation distances).
The ERG typically classifies substances with similar physical and chemical properties together. Liquefied natural gas (LNG), usually consisting primarily of methane in a mixture with small amounts of other hydrocarbons, has increased in use as a fuel source in recent years, and there is a potential for increased demand for the transport of LNG by rail and road. LNG is currently assigned in the ERG to Guide 115, along with liquefied petroleum gas (LPG). Therefore, the emergency actions for both LNG and LPG are currently identical. However, there are differences in the way the substances are transported that may alter their hazard profile if an incident were to occur. For example, LPG is liquefied under pressure, and is transported in single-walled containers capable of sustaining these pressures during transport. By contrast, LNG is liquefied under extremely low temperatures. The product is kept cold using double-walled tanks, with insulation, that are not suited for the higher pressures required for the transportation of LPG. There are other key differences in these two substances that could suggest that their hazard profiles are different and thus, may warrant being placed in different guides in the ERG. For example, LNG forms pools of liquid product when released, whereas LPG generally does not, thus their dispersion profiles following a release are different.
TC is looking to obtain the services of a contractor to comparatively analyze LNG to LPG in terms of the hazard profile based on its physical and chemical properties, and past incidents involving a release of these products, including those involving fires and/or resulting in BLEVE events. The objective of the research is to demonstrate the differences and/or similarities between LPG and LNG in order to inform decisions related to its emergency guide assignment in the upcoming editions of the ERG, or to inform additional research that might need to be undertaken to make this determination
