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A large Research and Development programme has been executed by National Grid to determine the feasibility of transporting carbon dioxide (CO2) by pipeline. Such pipelines would be required to form a transportation system to take the CO2 from its place of capture at an emitter’s site to a place of safe storage within a Carbon Capture and Storage (CCS) scheme. This programme received financial support from the European Union. As part of this programme, National Grid commissioned a series of experimental studies to investigate the behaviour of releases of CO2 mixtures in the gaseous and the liquid (or dense) phase. This has included simulating accidental releases in the form of punctures or ruptures of a buried pipeline and deliberate releases through different venting arrangements. This work is required, as CO2 has the potential to cause some harm to people if they are exposed to it for long enough at high concentrations. This paper gives an overview of the findings from this work and shows how the data has been used to help develop a number of the more pragmatic, predictive models for outflow and dispersion. This work complements the more theoretical studies carried out using state of the art advanced computational fluid dynamic models, employed by other UK based participants (University College London, University of Leeds, Kingston University and the University of Warwick) in the research programme.

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Failures of natural gas transmission pipelines have occasionally occurred around the world. Ignited releases from ruptured high-pressure transmission pipelines produce a highly transient thermal radiation field in the initial stages, as described in papers presented at IPC previously. In the context of risk assessment, modeling the effects of fires on buildings is as important as modeling the thermal radiation field. A simplistic approach may not be appropriate, particularly when there is a significant difference in thermal radiation levels between the nearest and the furthest points of the building from the fire. It is necessary to consider the timescales involved, such as the timescale for fire spread through the building, for the evacuation of people and for the external thermal radiation field to decline. All of these factors need a modeling approach that is commensurate with other uncertainties in the risk analysis. The purpose of this paper is to describe a general modeling approach to assess the effects of transient fire loading on such large buildings. Illustrative examples are given for a large two-storey building and an apartment block. The effects of parameter variations, such as changes in the rate of flow of people through a doorway and the rate of progress of people from one floor to the next, are demonstrated. The results help to establish a method for evaluating the risk to occupants of large buildings. This can be used to support informed decisions on pipeline safety issues and in prioritizing integrity management programs on a risk basis.