Case II : (t 3 . > (t ) -^t 

 r 1 r 1+1 



where 



s = 



n - t/ (t ) . for t < (t ) . 



f.Ct) = - C4) 



(O for t > Ct ) • 



\ ^ r 1 



(1 - t/(xp.,i for t < (T ) 



(O for t > (T ). 



hCt) = 



(t/(T ) . , for t < (t ) . , 



I ^ r-^i + 1 - r^i + 1 



(l for t > (t ) . , 



^ r^i + 1 



time since ignition of cell (i+1) 



fx ) . = residence time of cell i 

 r 1 



(t ) . , = residence time of cell (i+1) 



(6) 



Rj, = rate of spread as the fire passes from cell i to cell (i + 1) 

 R^^^ = quasi-steady state rate of spread in cell (i+1) . 



The terms fj^(t) and ^2^^^ ^-"^^ time dependent decreasing influences from cell i 

 while h(t) is a time dependent increasing influence from cell (i+1). 



A graphical representation of the "influence" factors f^ (t) , f2(t), and h(t) 

 are given in figure 8. 



Figure 8. — InfZuenaing factors governing fire transition from cell i to cell (i+1) 



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