The heat flux received from the Bunsen flame by the polymer specimen in the UL94 test is unknown, which makes the UL94 test elusive and difficult to be correlated with other fire tests such as the cone calorimetry. In this article, a copper slug with thermal sensor was applied to derive the heat flux according to ASTM D 5207-03. With the lumped heat capacity method and the least square method, the convective heat transfer coefficient and the flame temperature were regressed to be 54.31 W/m2/K and 2026 K, respectively, which corresponds to an initial convective heat flux approaching 100 kW/m2. A multidimensional convective heating model was presented. Ignition times predicted by the model agreed well with ignition times measured through proposed test procedures, which verified the regression results and convective heat transfer characteristics of the UL94 vertical burning test. Furthermore, the edge effect was found to be significant in predicting ignition times. Apart from the heat flux, the edge effect was also an important factor, which should be considered for correlating the UL94 test with the cone calorimeter test.
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