Water protection of surfaces exposed to impinging LPG jet fires

Abstract

The ability of water spray systems to combat the effect of impinging, two-phase, LPG jet fires has been investigated theoretically. The investigation covers a range of flow and flame parameter values spanning known and estimated large jet fire condition. The results show that water mass fluxes required to deal with impinging jet fires may be between 60 and 120 kg min−1 m−2. These are considerably greater than the rates employed in conventional cooling systems. Although the higher fluxes can be met by a range of existing spray nozzles, it is shown that droplet sizes produced by medium velocity nozzles, commonly used for cooling purposes, are likely to be too small to survive even short projection paths through these fires. Adequate spray water installations could possibly be designed around high velocity nozzles. Water monitors are, theoretically, also suitable for cooling surfaces exposed to impinging LPG jet fires.