(44ba) Domino Effect Model Applied to the Hertfordshire Oil Storage Terminal (Buncefield Oil Depot)

The Buncefield fire was a major accident that occurred in the Hertfordshire Oil Storage Terminal, on December 11, 2005. A series of failures during operations in the terminal resulted in a petrol overflow in one of the tanks (believed to have started at 5:20 a.m.), which went unnoticed for about forty minutes, resulting in a continuous release of the product during a significant amount of time. Although the product was spilled into a bund in which several tanks were placed, limiting the size of the release, a flammable cloud of considerable dimensions formed, and started drifting through the terminal. At 6:01 a.m. the first (and largest) of a set of explosions was registered, meaning that the cloud reached an ignition source at this point. After the first explosion, subsequent accidents, involving other explosions and fires occurred in a domino effect, destroying 20 storage tanks and causing 43 injuries and millionaire losses. The event has been described as the worst of its type in the UK since the Flixborough disaster in 1974.

In this work, a model that can be used to estimate the impact of the domino effect on accident frequencies in Quantitative Risk Assessment (QRA) of storage installations, developed by some of the authors, and published in the Process Safety and Environmental Protection Journal, has been applied to a layout based on the Hertfordshire Oil Storage Terminal, in order to determine the differences that would exist in the results of two QRAs of the installation, one performed in the traditional way, and another taking in to account the domino effect.

This will be done to test the model, proving if the domino effect sequences generated are similar to the one that occurred in the actual accident. Also the iso-risk and F-N curves obtained in the two QRAs performed will be compared, in order to assess if the inclusion of domino effect on the study will have a significant effect on the risk associated to the installation.