High pressure jet fires pose a serious hazard to offshore installations operated by the oil and gas industry as demonstrated by the Piper Alpha incident. Following the Piper Alpha incident a major initiative by the offshore oil and gas industry operators led to the production of Interim Guidance Notes which provided guidance to operators on how to assess jet fire hazards. However, many areas of uncertainty were identified where no data was available. Areas of particular concern identified in the Interim Guidance Notes were two-phase jet fires, the effect of confinement on jet fires and their behaviour with water deluge. Since that time a considerable body of experimental research has been undertaken. Based on this recent data, this paper reassesses jet fire hazards in an offshore environment and provides updated guidance on the hazards they pose, including tabulated data and simple calculation techniques for predicting jet fire hazards.