An experimental study of the transient build-up of a methane fire located in an in-line room corridor small scale test facility has been conducted. The data is specifically designed to be used for evaluation and development of transient field models as well as global models which predict these flows. Local temperature and velocity data were taken at the center line of the facility at various axial locations along with flow visualizations using smoke injection techniques. The data are presented in two forms which show the transient development of floor to ceiling profiles as well as the time history at single points. It was found that the data for the first minute after ignition of the methane flame were adequate to characterize conditions when adiabatic walls are assumed. The data of this study show some significant differences from previously published studies.