A computer simulation for upward fire spread has been developed. The simulation of the fire growth and spread consists of four major components (modules): 1) preheating of the unburned fuel, 2) upward fire spread, i , e. determination of the location of the pyrolysis front, 3) pyrolysis of the material, and 4) combustion of the pyrolyz ing gases.For the heat-up and pyrolysis modules of the code, integral models have been used which accurately predict (within 1% to 2%) transient heat-up and transient pyrolysis when compared with exact analytical~olutions.The pyrolysis front location, 2 , is calculated to order (62) by taking an intercept of a straight line, cgnnecting the temperatures (real and/or virtual) of the nodes containing 2 p' with the pyrolysis temperature T p' The combustion module of the code calcUlates the heat flux distribution on the wall from the combustion of the py ro Iyz Lng gases by prov id ing expressions .for the flame he ight, 2 f' the convective, q~, and radiat i ve heat fluxes, q~, based on experimental data from the literature. The components as well as the whole algorithm of the Upward Fire Spread and Growth (UFSG) code have been compared against exact analytical solutions including transient heat-up, transient pyrolysis and flame spread.As an example, it is demonstrated that transient pyrolysis even for non-charring materials significantly affects upward fire spread rates. This result explains recent experimental data on laminar upward flame spread.In addition, a comparison of numerical predictions with turbulent upward flame spread data is made, and the results are very satisfactory.

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We demonstrate how flame spread and fire growth can be predicted in a systematic way using a fire spread and growth (FSG) model developed at FMRC and small scale flammability measurements for PE/PVC cables in trays; this material pyrolyses in a more complicated way than a non-charring (e.g., PMMA) or a simple chamng material (e.g., particle board). Similar methodology has been applied and validated for PMMA and various types of particle board. For PE/PVC cable trays, this procedure consists of the following parts: a) standard small scale flammability measurements (i.e., time to ignition, heat of combustion, product yields) and measurements of surface temperature histories and pyrolysis rates in a nitrogen atmosphere; b) a method to deduce from these small scale measurements "equivalent" material pyrolysis properties which can be inserted in a pyrolysis model to predict pyrolysis rates in fires; and c) the FSG fire spread model which uses the properties obtained in parts (a) and (b) for predicting fire growth and critical conditions for flame spread. The present work focuses on upward f i e spread predictions and measurements for a specific 3 ft high PE/PVC cable tray.

New flame extinction conditions for the critical mass pyrolysis rate are developed when extinction occurs by interaction of flames with the pyrolyzjng surface of a condensed m a t e d The extinction conditions provide the critical mass pyrolysis rate and the corresponding convective heat flux to the surface. A novel formulation shows that the sum of fuel mass fraction near the surface and the ambient oxygen mass fraction corrected for stoichiometry and incompleteness of combustion is constant. The extinction conditions are derived from simple analysis of combustion and heat transfer, and they are shown to be applicable for various experimental conditions such as fuel dilution by inert gas, oxygen dilution by inert gas, effects of external heat flux, material preheating, transient (charring) pyrolysis, including geometric effects which influence the critical mass pyrolysis rate through an effective heat transfer coefficient. Additional validation of the proposed extinction conditions is provided by numerical simulation reported in the literature in the regime of low straining rates for a stagnation flow on a cylinder. The present approach can be used to obtain the critical extinction conditions from measurements in a standard flammability apparatus.

This work presents experimental results and non-dimensional correlations of factors and conditions affecting carbon monoxide (CO) production in corridor-like enclosure fires. Thirty eight experiments were performed in a three metre long corridor-like enclosure having a cross section 0.5 m x 0.5 m, door-like openings in the front panel and a propane gas burner located near the closed end being flushed with the floor. Measurements of carbon monoxide concentrations were performed at locations inside the enclosure and also in the exhaust duct of a hood collecting the combustion products for direct comparison. Visual observations through the opening revealed that flames were detaching from the burner for tests with global equivalence ratios (GERs) greater than one for the burning inside the enclosure (underventilated fires). After detachment, flames were travelling towards the opening then finally stayed anchored in the vicinity of the opening and emerged outside. After flames were visible outside, the concentration of CO inside the corridor increases to much higher levels owing to the recirculation of gases inside the enclosure behind the flames. A correlation between CO concentration inside the enclosure and GER was found with CO increasing initially but then decreasing for high global equivalence ratios. An additional correlation was found between the CO yield and the GER in the enclosure before the flames reached and then, anchored at the opening of the enclosure. Finally, it was found that the ratio of CO to smoke yield, y co /y s , is not constant but increases for global equivalence ratios of the enclosure greater than one in contrast to its value being constant for over ventilated conditions.