This technical document reports on the validation of the furniture fire model with the furniture calorimeter data and on the restructure of the program "HEMFAST". Significant restructuring of the model and its code resolve various problems associated with the first version of HEMFAST. Comprehensive descriptions of the current model and its code structure benefit the HEMFAST users. The descriptions include: data processing of the bench scale fire tests database, effective time integrations of surface temperatures, flame spreads, and burn time, effective coupled solutions of pyrolysis rates, burnrates, soot production, and thermal radiation, and the effective interfacing between the furniture fire model and radiation, and (4) the effective interfacing between the furniture fire model and FAST. The model is validated with fire tests for a 4-cushion mockup fire with fire with three different fabric/foam cushion types. The comparisons include: burn area fractions of each cushion as a function of time, burnrate of the mockup as a function of time with fire test data from thefurniture calorimeter, mass loss rate of the furniture as a function of time, and the overall levels of soot production.