A multiphase, multimode heat transfer numerical model was used to estimate the maximum skin temperature of a stagnant water-filled pipe structure subject to an intense flame. This transient two-dimensional mathematical model takes into account conduction, convection and radiation as well as evaporation of cooling water. Results have been obtained based on practical data and experimental field findings. The cooling water film that surrounds the pipe structure attacked by the flames, can originate from fire-fighting water hoses or from a sprinkler water system. Two different values of water film thickness of 3 and 5 turn are analysed. The simulation results indicate that the main parameter which controls the pipe skin temperature, is the water film thickness covering the pipe. Indeed the maximum steel pipe skin temperature drops from 175.5 to 108.8degreesC when the water film thickness is increased from 3 to 5 mm for the 20 inch-water-filled pipes. However the water presence inside the pipe has negligible effect on the pipe skin temperature. Copyright (C) 2004 John Wiley Sons, Ltd.