A study of the effects that ammonium sulfate and ammonium phosphate have on flam- 

 mability must include quantification of several appropriate parameters. Many researchers 

 have used rate of fire spread to assist in the evaluation of fire retardants (Hardy, 

 Rothermel , and Davis 1962; Rothermel and Hardy 1965; Johansen 1967; Eickner and Schaffer 

 1967). The rate of spread is a measure of sustainability , or the ability of a fire to 

 propagate itself. The combustibility, or rate at which energy is released from the fire, 

 can be measured by monitoring the weight loss rate that occurs during the fire 

 (Rothermel and Hardy 1965; Rothermel and Anderson 1966). Only recently has it been 

 pointed out that retardant chemicals applied to open fuel bed fires may have similar 

 effects on the rate of spread but different effects on the rate of energy release 

 (George and Blakely 1970) . Because fire retardants are used to reduce fire spread and 

 combustion rate, it is necessary for both parameters to be quantified. 



Although ignitibility and sustainability may be encompassed in rate of spread 

 measurements, and combustibility in energy-release rate measurements, they do not entirely 

 describe a fire retardant 's effect on f lammability. Combustion can be divided into two 

 phases: flaming (associated mainly with the fire front); and glowing (associated with 

 residual burning) --different rates of energy release apply for each of these. The re- 

 tardant chemical, due to inherent decomposition characteristics, may only be available 

 at given temperatures or for a given time during the fire, (George and Susott 1971) thus 

 causing different effects on the flaming and glowing processes. The extent of combus- 

 tion, both flaming and glowing, can be determined by measuring the amount of residue. 



The quantification of the effects that fire retardants have on rate of spread, 

 energy release rates, and residue should provide a basis for determining the chemical's 

 overall effect on f lammability . 



Objectives 



The major objective of this study was to determine the effects of ammonium sulfate 

 and ammonium phosphate on the f lammability of cellulosic fuels. The overall effects on 

 flammability can be characterized by quantification of these effects on the following 

 parameters : 



1. Rate of spread (R ) 



2. Rate of weight loss (R ) 



3. Residue (R) W 



Standard curves were developed in this study for each parameter as a function of the 

 amount of retardant chemical applied to the fuel. 



The study was designed to provide general information which can be used to evaluate 

 formulated ammonium sulfate and ammonium phosphate fire retardants. The curves will be 

 used to evaluate the relative importance of additives, or impurities, and to determine 

 whether they enhance or reduce the active chemicals' effectiveness. This information 

 will be useful to potential suppliers for the formulation of more efficient fire 

 retardants . 



Also, this study will provide information which may eventually be used in the 

 development of operational guidelines. The guidelines could assist fire control 

 personnel in selecting the most efficient retardant chemical for a given job and help 

 determine how much chemical is required for the specific situation. 



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