This numerical investigation of lifted diffusion flames examines the interaction of flame and surface from a heat transfer perspective. Conduction is the primary mode of heat loss from the laboratory-scale flame. Heat flux profiles to the lower chemically inert boundary are obtained for three different models: a finite-rate chemistry model, a simplified heat conduction model, and the limiting case Burke-Schumann model. Generalizations are made about the shape of the heat flux profiles to the anchoring boundary, as well as the practical usefulness of the presented models. A characteristic flame thickness is also defined from the generalized heat flux shape. (C) 2000 Elsevier Science Ltd. All rights reserved.