Burning rate is a key factor in modeling fire growth and fire endurance of wood structures. This study investigated the burning rate of selected wood materials as determined by heat release, mass loss and charring rates. Thick samples of redwood, southern pine, red oak and basswood were tested in a heat release rate calorimeter. Results on ignitability and average heat release, mass loss and charring rates are reported for a heat flux range between 15 and 55 kW m-'. In this range, burning rate increased linearly with heat flux. Burning rate was very species dependent. Heat release rate was related to mass loss by effective heat of combustion, which also increased with heat flux. Charring rate was related to mass loss rate and original wood density. Important char property data such as yield, density and contraction are reported. A simplified calculation method is proposed for calculating mass loss rate and charring rate based on heat release rate. _ _ _ _ _~

Compartment fire zone models are based on many simplifying assumptions, in particular that gases stratify in two distinct layers. Because of these assumptions, certain model output is in a form unsuitable for direct comparison to measurements made in full-scale room tests. The experimental data must first be reduced and transformed to be compatible with the model output. In this article, new techniques are described to calculate neutral plane height, vent flow rates, uniform upper and lower layer temperature and interface height from measured temperature profiles. The new calculation procedures conserve mass in the room. The procedures were used for data reduction of a series of 8 gas burner calibration room tests. The results of one of the tests are discussed in detail as an illustrative example.

As part of a fire growth program to develop and validate a compartment fire model, several bench-scale and full-scale tests were conducted. This paper reports the full-scale wall and corner test results of step 2 of this study. A room fire test following the ASTM proposed standard specifications was used for these full-scale tests. In step 1, we investigated the combination of factors for evaluating wood products in wall and corner fire tests. They were the position of the ignition source, power output from the source, and combination of lining materials. We concluded from the sensitivity study (step 1) that for wall and corner fire tests, a burner output program consisting of 40 kW exposure for 5 min followed by 160 kW exposure for 5 min was the most informative.In this paper, step 2 of the research program, results from wall and corner tests using six wood materials having different flame spread indices (according to ASTM E 84) are given. The two-step burner setting was confirmed to be better than a constant setting for evaluating wood materials. The relative performance of these materials was in line with their ASTM E 84 flame spread properties. Smoke release rates obtained by white-light and laser systems showed excellent agreement. Only rate of heat and smoke release, selected tempera-

A room test designed according to the ASTM draft standard was used to investigate the effect of various parameters on the contribution of wall and corner fires to compartment fire growth. Location of the burner (against a wall or in a corner), power program of the gas burner ignition source, and combination of wall linings were varied. An initial series of calibration tests were conducted on ceramic fiber blanket and gypsum board. These tests showed satisfactory instrumentation, good repeatability, and reliable data reduction techniques. The second series were wall and corner tests with Douglas-fir plywood on the walls in contact with the burner and either ceramic fiber or gypsum on the ceiling and remaining walls. Notably, fire growth was much faster in the tests with ceramic fiber. We conclude from the data analysis that at least for corner tests, gypsum board should be used for the ceiling and remaining walls as specified in standardized procedures. A burner program of 40 kW for 5 min followed by 160 kW for the next 5 min was the most informative program; it will be used for wall and corner tests in subsequent steps of this ongoing study.

Modeling fire growth over wall linings in a compartment requires experimental data and a model of the fire source. Limited information is available for flames against a wall or in a corner. Steadystate experiments were conducted to characterize the corner ignition source used in the proposed ASTM room fire standard at two heat release rate levels, 40 kW and 160 kW, with natural gas and a mixture of natural gas and toluene as the fuel. Flame height, heat flux to wall, temperature, velocity, mass and enthalpy flux, and flame structure were measured primarily in the flaming region. Correlation calculations included flame height as a function of heat release rate, and temperature, velocity, and mass flux for corner flames as a function of heat release rate and height. I NTRODUCTION Fire growth on a wall and in the comer between two walls has been the subject of a joint study between the USDA Forest Service, Forest Products Laboratory (FPL) and the American Forest & Paper Association in the past few years 1-2 . The FPL room fire test facility has served two purposes: (a) to evaluate fire growth on wall linings, and (b) to develop and validate wall and corner fire models.The first purpose is fairly straightforward, while the second is complicated by factors involved in predicting fire growth, a major concern being the ignition source. In a sensitivity study, Tran and Janssens' examined the effect of burner setting on wood performance. In a subsequent study, a number of different wood products were tested using a burner program consisting of two steps: 40 kW for 5 min, followed by 160 kW for another 5 min2. Most wood products tested required 160 kW exposure to cause flashover, except for fire-retardant-treated wood, which did not result in flashover in these experiments.To model the fire growth on the walls, the ignition source (burner) needs to be well characterized. While much work has been done on the structure and characteristics of axisymmetric flames and plumeS3-1r,, little