This paper considers the negatively buyoant, two-dimensional wall flows that arise at the early stages of the growth of a compartment fire. Such flows affect the distribution of mass, momentum and energy between the two zones, that the fire environment is generally assumed to be comprised of in the mathematical modeling of enclosure fires. An experimental study is carried out to determine the important thermal characteristics of such negatively buoyant wall flows, particularly the entrainment into the flow, the penetration distance and the heat transfer to the walls of the enclosure. Employing analytical and experimental results of buoyancy driven wall and plume flows, the resulting effects in compartment fires are determined. It is shown that the wall flows are extremely important at the very early stages of fire growth, particularly during the establishment of the two zones in the enclosure. Also, the additional transport generated by buoyancy induced wall flows, following the establishment of the zones, is found to be important in a satisfactory modeling of the changing environment in the enclosure.