Experimental Studies of Releases of High Pressure Natural Gas From Punctures and Rips in Above-Ground Pipework

Abstract

The gas industry has an excellent safety record in operating high-pressure transmission pipelines.Nevertheless, it is important that pipeline operators have an understanding of the consequences of possible accidental gas releases, in order to help manage the risks involved. This paper presents a programme of full scale experiments, undertaken by an international collaboration of gas companies, to study the consequences of both unignited and ignited releases of natural gas from simulated punctures and rips in a 900mm diameter above-ground transmission pipeline. Experimental parameters varied during the programme included release orifice size and shape, release pressure, release height, release direction, wind speed and wind direction. Instrumentation was deployed to obtain detailed data on the dispersion of gas, the ignitability of the gas cloud produced, the levels of incident thermal radiation and the resulting fire size and shape, following ignition. The results provide important data for the validation of mathematical models, used in developing risk assessment methodologies for gas pipelines, and in establishing those standards and design codes that are risk based.

Simplified expression for estimating release rate of hazardous gas from a hole on high-pressure pipelines

“…The existence of frictional force in an actual flow situation might affect the resultant flow characteristics significantly, and makes the analysis of the gas release phenomena quite complex (Fthenakis, Rohatgi, & Chung, 2003;Hankinson, Lowesmith, Genillon, & Hamaide, 2000;Jo & Ahn, 2003;Montiel, Výlchez, Casal, & Arnaldos, 1998;Yapa & Zheng, 1997;Zheng, Luo, Zhao, Zhou, & Li, 2004).…”

A Full Scale Experimental Study of Fires Following the Rupture of Natural Gas Transmission Pipelines

“…Nevertheless, it is important that pipeline operators have an understanding of the possible consequences of an accidental gas release, which may ignite, in order to help manage the risks involved. To obtain such information, an international group of gas companies has collaborated to undertake a research programme, including experiments at small and large scale [1], mathematical modelling [2], and culminating in two full scale pipeline rupture experiments performed in Canada. Validation of any mathematical models which attempt to predict the behaviour of such events, at as close to full scale as possible, is essential due to the strongly scale-dependent nature of the physical processes involved.…”