Insights into and the evolution of a novel predictive model for free burning wooden cribs

The extensive work on wood crib fires, both experimental and model development over the last six decades is examined in some detail. The wide range of parameters of crib tests and the theories have been reviewed in the literature and a satisfactory correlation has still to emerge from these studies. From early times, the burn flux (g/m s) has been considered the most appropriate parameter to characterise the burn behaviour of the cribs. These data on a re-examination revealed a surprisingly simple behaviour of a linear variation of the mass loss rate (g/s) with the mass of the crib, particularly for smaller size sticks with the crib placed on the ground. Some insight into this behaviour is brought out and the basic idea has been pursued to reveal an alternate and a more accurate correlation for the burn rate with crib mass and the crib size as principal parameters with the crib height-to-spacing ratio providing a minor correction. The resulting correlation has been compared with over a hundred and fifty experimental data along with a modified Thomas correlation and shown to perform much better for smaller-size sticks.