Dimensionless factors in a solution

By normalizing the steady equation with the air flow rate and representing all of the losses as linear in T (Equation (11.31)), the temperature rise can be solved as 

The dimensionless x-loss factors are parameters that effect temperature, and occur in modified forms in many correlations in the literature for compartment fire temperature. 

Flow-loss factor. The flow factor, x0, is the ratio of out-flow to airflow  

Wall-loss factor. The wall-loss factor, xw, is given in terms of the compartment heat transfer surface area, A, and the overall heat transfer coefficient, h, as given by Equation (11.17)  

the maximum air flow rate could be inserted per Equation (11.7). In general, h depends on convection (hc), radiation (hr) and conduction into the walls (hf). Their typical values range as hc 10-30, h, 5-100 and (kpc/t) /2 5-60 W/m2 K consequently, h 1 to 100 W/m2 K is a typical range expected. It is important to note 

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