let r' = r corrected for surface area 



where w = amount of retardant applied per unit area 



let r" = r Q corrected for surface area and vapor pressure 



Pv " Pvj 



where p v = vapor pressure at surface of retardant 

 o 



p v ^ = vapor pressure in free stream atmosphere 

 let r = r Q corrected for surface area, vapor pressure and air velocity 



r w 

 o o 



r - 



U(p v - P Vl ) 



o 1 



where U = air velocity above fuel bed. 



Numerical values for these corrections are shown in table 4. The resulting average value of r 

 is 1.14X10 -6 . Inserting the corrections for r and the new value of r, equation (2) becomes: 



M = M Q exp - 1. 14X10- 6 



U(p Vq - P Vl )t 



where M = amount at any time, grams 



w 

 li 



(5) 



Hi 



M will assume the units of M . M Q may be in total values such as pounds or grams or 

 gallons, or it may be in unit values such as grams per square centimeter, pounds per square 

 foot, or gallons per hundred square feet. 



Table 4. --Determination of drying rate factor r 



Condi- 

 tion 



: Amount ; 

 :gal./100 : 

 : sq.ft. : 



r o 



: M 



] grams 



g/cm. 



: r' : 



Ave. r : 



mm . 



Hg. 



r" 



; u 



'cm ./sec . 



r 



I 



1 



0.010950 



97.46 



0.03497 



3.829X10- 4 



4.007xl0- 4 3 



.94 



1 .017x 10~ 4 



89.4 



1. 138x1 0- e 





2 



.005513 



204.34 



.07332 



4.042XICT 4 















3 



.003633 



318.40 



.11420 



4. 149X10- 4 













II 



1 



.018350 



84.32 



.03027 



5.554X10" 4 



5.800X10- 4 5 



.56 



1.043X10-4 



89.4 



1. 167xl0- e 





2 



.008600 



186.72 



.06703 



5.764X1CT 4 















3 



.005830 



290.94 



.10440 



6.068X10- 4 













UI 



1 



not used 



65.52 



.02352 





1.38X10- 3 5 



.56 



2.489X10~ 4 



223.5 



1.114xl0- e 





2 



.022270 



161.28 



.05790 



1.289X10- 3 















3 



.015360 



268.00 



.09621 



1.478X10- 3 













Ave. r = 1 . 14V 10~ e 



19 



