A framework for minimizing domino effect through optimum spacing of storage tanks to serve in land use planning risk assessments

The recent interest in optimizing land use through integrated risk assessment, which intensified after Buncefield oil depot incident in 2005, calls for, among other things, determination of domino effects, which can be severe. The recommended tanks spacing and water application rates by design codes vary widely and are sometimes contradicting, if not subjective. This paper introduces a novel framework to determine the water application rate for protection of storage tanks against thermal radiation from an external non-contacting fire through first principles modeling. This new approach has been applied to assess the appropriate cooling water rate needed for the protection of an existing crude oil tank farm which includes three one-million barrel and two 500,000-barrel floating roof tanks. The tanks are to be protected from the thermal radiation of an adjacent tank with a full surface fire by application of cooling water and in the present arrangement they are so widely spaced that this is only attributable to a generous 'overdesign'. It has been shown that applying the new approach could have resulted in at least 25% saving in tank farm area.