Instantaneous liquid release from a rail tanker: The influence of noise shields on pool shape and pool size

Abstract

In the Netherlands, the Betuweline is a dedicated freight railway. It will, among other things, be used for transportation of all kinds of hazardous materials from the Port of Rotterdam to the German Hinterland and vice versa. The line is approximately 150 km long. Alongside the line, more than 100 km noise shields have been constructed. The question is how, and to what extent, this noise shield will affect the pool shape and size of an instantaneous release of a flammable liquid, such as liquefied petroleum gas (LPG). In case of an instantaneous release of liquid from a rail tanker (50 m 3), both risk analysts and emergency responders use a circular pool shape of about 600 m 2 would result. To assess the influence of a noise shield, a full scale test was conducted on an already constructed part of the Betuweline. A rail tanker was filled with 50 m 3 red-colored environmentally safe liquid. The liquid was instantaneously released. A very peculiar pool shape actually results due to the presence of a noise shield. A zone between the rails and the noise shield (2 m wide and 90 m long) is within 2–3 min filled with 15 cm of liquid. The total pool size area was about 750 m 2. Both shape and size deviate substantially from the traditional figures. These insights are both relevant to emergency responders for disaster abatement purposes and to risk analysts for effective modeling purposes. The Dutch Ministry of Transport is examining possible strategies to deal with these results. The results of this study are based upon one single instantaneous release test. In addition, it is valuable to find out what the pool shape and size would be in case of a continuous release from the rail tanker near a noise shield.