The bonfire test is an important prototype test in the standard of hydrogen storage vessels. It is designed to demonstrate the safety performance of the vessel and the Pressure Relief Devices (PRD) under a specified fire condition. However, the required temperature of the thermocouples, which is one of the most relevant parameters, is still not unified. The fuel types and fuel flow, which may influence on the temperature distribution and the PRD activation time, are also not specified in the standards. In this paper, an experiment was carried out on a composite vessel filled with hydrogen and the experimental results of temperature and pressure were obtained. A 3D simulation model was developed to study the bonfire test. The effects of fuel type, fuel flow and filling medium on the temperature rising of internal gas were studied. It reveals that the influence of fuel type on the temperature rising is significant. In addition, the rate of temperature rising increases as the fuel flow increases. However, the filling medium has little effect on the temperature rising. (c) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.