1 . Application of the total specified amount of retardant on the upper surface of the com- 

 pleted fuel bed. (Preliminary burning tests had shown this to be feasible.) 



2. Use of an application device that would not aerate the retardant. This was done by 

 pressurizing the supply tank just enough to force the liquid out the bottom into a manageable 

 spray pattern. 



3. Selection of a nozzle and pressure combination that effectively prevents formation of 

 fine mist and large globs. 



4. Use of a flat or single-plane nozzle to obtain a uniform lateral spray pattern over the 

 full width of the fuel bed. 



5. Reduction of particle velocity to as near terminal rate as possible without sacrificing 

 requirements of droplet size, spray pattern, or flow rate. 



6 . Increasing application time to permit better control of application amount by reducing 

 flow rate as much as practicable. The rate achieved was between 1.7 and 2.0 gallons per 

 minute . 



Equipment 



AppUcation equipment consisted of 

 a 12-foot-long spray chamber with tracks 

 along each side to support the carriage 

 containing the pressurized applicator 

 (fig. 1). 



Figure 1 . - - Application 

 equipment. 



Airw 



A. Complete spray rig 



-Pressure regulator 



Air hose' 

 coupler 



Air @ 

 1215 psi 



' Liquid ' 



-Filler hole & 

 pressure cap 



-Ball valve 



\^ ][\ Nozzle 



B. Pressure system 



5 



