"Alternate models for extended ceiling convection heat transfer and ceiling vent mass flow for use in the Harvard Computer fire Code are developed. These models differ from current subroutines in that they explicitly consider the ceiling jet resulting from the fire plume of a burning object. The Harvard Computer fire Code (CFC) was used to compare the alternate models against the models currently used in CFC at Worcester Polytechnic Institute and with other available data. The results indicate that convection heat transfer to the ceiling of the enclosure containing the fire may have been previously underestimated at times early in the fire. Also, the results of the ceiling vent model provide new insight into ceiling vent phenomena and how ceiling vents can be modeled given sufficient experimental data. this effort serves as a qualitative verification of the models as implemented; complete quantitative verification requires further experimentation. Recommendations are also included so that these alternate models may be enhanced further. "