Experiments on Large-Scale Fires Reveal Benefit of Greater Water Deluge

Abstract

This article, written by Editorial Manager Adam Wilson, contains highlights of paper SPE 164973, ’The Effect of Deluge Spray Systems on Large-Scale Fires,’ by Stian Hoiset and Eli Glittum, Statoil, prepared for the 2013 SPE European HSE Conference and Exhibition, London, 16-18 April. The paper has not been peer reviewed. A series of 56 large-scale fire experiments in the range of 40–120 MW has been carried out in a generic offshore module. The effect of deluge fire-water application has been measured for different setups. Both deluge nozzle type and water-application rate have been varied in the experiments. Introduction The use of water-spray systems for fire-fighting is standard for most offshore oil and gas installations. The requirements to and guidelines for control and mitigation of fires are stated in International Organization for Standardization (ISO) 13702, Petroleum and Natural Gas Industries—Control and Mitigation of Fires and Explosions on Offshore Production Installations—Requirements and Guidelines. Appendix C in ISO 13702 lists the recommended fire-water-application rates for areas and rooms on an oil- or gas-production installation. Typically, the minimum recommended water-application rate is listed as 10 (L/min)/m. NORSOK Standard S-001, applicable for installations on the Norwegian continental shelf, states that the effect of deluge may be taken into account for process equipment and piping, provided that there is proper documentation of the fire-water effect (and that there are requirements to the reliability of the fire-water system). In order to document the effect of the recommended fire-water-application rate, a set of full-scale fire experiments with application of fire water was carried out at SINTEF NBL. Background Today’s design of oil- or gas-production installations includes deluge-fire-water systems as standard. These are costly and may require extensive maintenance. Despite the costs involved, little knowledge is available on the actual effect of fire-water systems under different operating conditions. Appendix C in ISO 13702 recommends a typical water-application rate of 10 (L/min)/m. National Fire Protection Association (NFPA) 15: Standard for Water Spray Fixed Systems for Fire Protection recommends a design objective for control of burning of not less than 20 (L/min)/m. NORSOK S-001 refers to NFPA 15 but prescribes 10 (L/min)/m for process areas and equipment surfaces and 20 (L/min)/m for the wellhead area. American Petroleum Institute (API) 2030, Guidelines for Application of Water Spray Systems for Fire Protection in the Petroleum Industry, prescribes 20 (L/min)/m where pumps are present and 10 (L/min)/m for pipe racks and piping. To what extent do these water-application rates actually affect the fire?