Polymer's melt flow behavior has triggered great interest due to the mutual-enhancing loop effect between vertical polymer fire and the induced flowing pool fire. The aim of the study was to quantitatively investigate the effect of ignition conditions on the polymer's melt flow flammability. Polypropylene (PP) sheets with a thickness of 4 mm were selected as the test samples. An experimental rig was designed to study the interaction between the vertical PP sheet fire and the corresponding pool fire. Ignition was achieved at three locations, i.e. the lower right corner, the lower middle edge, and the whole lower edge of the PP sheets. All tests were conducted in an ISO9705 fire test room. Heat release rate, smoke temperature and other common parameters in fire hazard analysis were measured with the help of the fire room facilities. Results indicated that ignition conditions evidently impact on heat release rate development, peak heat release rate, smoke temperature, smoke generation and smoke toxicity. Furthermore, these experimental results preliminarily demonstrated the feasibility of the designed setup in studying interaction between vertical polymer sheet fire and the induced pool fire, although further modification may be needed. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.