Previous work has shown that directed water deluge systems designed to just give the current recommended minimum rate of ca. 10 dm(3) m(-2) min(-1) provide inadequate protection of liquefied petroleum gas (LPG) storage vessels against flashing-liquid propane or butane jet fires. However, the results suggested that an enhanced design could be effective. This paper describes the work carried out by the Health and Safety Laboratory (HSL) to determine a deluge design for protecting against flashing-liquid propane jet fires. A suitable design was found for at least protection against ca. 2 kg s(-1) flashing propane jet fires and this design was used to investigate the effect of blocked nozzles and delayed deluge initiation. Crown Copyright (C) 2003 Published by Elsevier Ltd. All rights reserved.