22 inches above the fuel bed surface to measure flame temperature. Analysis of the 

 flame size for each test set (consisting of 3 or more fires) indicated which 

 thermocouples were in the flame envelope. From these thermocouples an average flam.e 

 temperature was determined. This was used to determine an average blackbody emissive 

 power. The average emissive power of the flame was also determined by considering 

 the heat rate sensor value at discrete distances from the flame. The emissivity of 

 the flame was determined as described for the combustion zone. 



A preliminary series of tests was made with ponderosa pine needle beds to assess 

 the magnitude of the influence of porosity. Fuel beds of 0.5 and 1.0 f t . ^ load area 

 and constant loadings were burned as stationary fires with surface ignition. The fue] 

 depth was varied to provide various porosities and measurements of weight loss and 

 flame length were made. 



The radiant heat fire tests were conducted with three replications in three pine 

 needle fuels--ponderosa pine ( Pinus ponderosa Laws.); western white pine ( Pinus 

 monticola Dougl.); and lodgepole pine ( Pinus contorta Dougl.). The fuels were 

 conditioned to moisture contents varying from 2.5 to 23 percent of ovendry weight. 

 Mbient conditions were maintained at 90° F. with relative humidities of 7 to 92 

 percent; ambient conditions were matched to fuel moisture contents. Fuel beds were 

 prepared according to established technique (Schuette 1965) . A summary of the test 

 conditions and fuel characteristics is given in table 1. 



Table 1 . -- .Ambient conditions and fuel characteristics for each test set 

 {.\ set constitutes three or more fires) 



Fue J 



type 













Particle 









Heat to 



Fuel heat 



§ moisture 



Air 



Relative 





density 





A 





ignition 



content 



content 



temperature 



humidit)- 



'a 



c 



f 













H 





0, 



■6 





If. 





% RH 



ft.2/ft. 3 



lb. /ft. 3 



ft 



. Vft.2 



B.t .u. /lb. 



B.t.u./lb. 



PP 



- 2 



6 



90 



5 



7 







1,741 



31 



S 



9 



1 .X 



10"- 



215 



8,744 



PP 



- 4 



2 



90 



S 



13 



2 



1,741 



31 



8 



S 



8 X 



10'' 



257 



8,744 



PP 



- 5 



3 



90 



5 



22 



2 



1,741 



31 



8 



9 



1 X 



10-3 



254 



8,744 



PP 



5 



9 



90 



7 



■30 



7 



1,741 



51 



8 



8 



5 X 



10 3 



262 



8,744 



PP 



- 8 



6 



90 



8 



51. 



3 



1,741 



31 



8 



S 



5 X 



10-3 



500 



8,744 



PP 



- 14 







90 



3 



75 



3 



1,741 



51 



8 



8 



5 X 



10-3 



547 



8,744 



PP 



- 20 



5 



90 



5 



92 



2 



1,741 



51 



8 



S 



4 X 



10 ' 



577 



8,744 



IVP 



3. 



4 



90 



6 



6. 



1 



2,790 



35 



5 



5 



9 X 



10-3 



227 



8,457 



IVP 



- 6. 



7 



91 



1 • 



21. 



6 



2,790 



33 



5 



5. 



6 X 



10-3 



275 



8,457 



WP 



7 . 



4 



90 



5 



30. 



9 



2,790 



33 



5 



5. 



5 X 



10-3 



285 



8,457 



WP 



- 10. 



1 



90 



8 



51. 



2 



2,790 



33 



5 



5 



6 X 



10-3 



517 



8,457 



WP 



- 15 



3 



90 



4 



75. 



8 



2,790 



33 



5 



5. 



6 X 



10-3 



555 



8,457 



WP 



- 21. 



6 



90 



5 



91. 



3 



2,790 



33 



5 



5. 



6 X 



10 3 



5SS 



8,457 



LPP 



5 . 



6 



92 



2 



6. 



2 



2,188 



55 



4 



4. 



6 X 



10"3 



250 



8,748 



LPP 



- 5. 



4 



90 



8 



21. 



9 



2,188 



55 



4 



4. 



8 X 



10-3 



260 



8,748 



LPP 



- 6. 



5 



90 



8 



31. 







2,188 



55 



4 



4. 



5 X 



10-3 



270 



8,748 



LPP 



- 8. 



8 



90 



8 



51. 



1 



2,188 



35 



4 



4. 



5 X 



10-3 



501 



8,748 



LPP 



- 13. 



4 



90. 



7 



75. 



8 



2,188 



55 



4 



4. 



9 X 



10" 3 



545 



8,748 



LPP 



- 25. 



2 



90 



1 



91. 







2,188 



55 



4 



5. 



X 



10-3 



402 



8,748 



PP is ponderosa pine 



WP is western white pine 



LPP is lodgepole pine 



7 



