Citation

Hartman JR, Waters CA, Beyler CL. Fire Mater. 2007; 31(6): 359-371.

Affiliation

United States Naval Academy, 572 Holloway Road, Annapolis, MD 21402, U.S.A.; Hughes Associates Inc., 3610 Commerce Drive, Suite 817, Baltimore, MD 21227, U.S.A

Copyright

(Copyright © 2007, John Wiley and Sons)

DOI

10.1002/fam.941

PMID

unavailable

Abstract

This study measured the Arrhenius kinetic parameters and heat of reaction using thermogravimetric analysis (TGA) and differential scanning calorimetric (DSC) for the combustion of untreated towels and towels treated with cerium(IV) nitrate. These parameters were used to calculate the self-heating parameters, M and P (Self-heating: Evaluating and Controlling the Hazard. Her Majesty's Stationery Office: London, 1984) and the critical pile sizes of the towels at several temperatures. The results from the TGA/DSC experiments support the conclusions by Beyler et al. (Fire and Materials 2005; 30:223-240) that the cerium(IV) nitrate treatment of towels significantly enhances the ignitability of the towels but that self-heating is not a hazard for normal temperature storage scenarios other than bulk storage.It was found that the kinetic reaction data measured by TGA and DSC are only useful for predicting the specific reaction hazard for materials stored above 100 degrees C. A comparison of the self-heating parameters measured by oven and kinetic reaction data methods for a number of materials suggests that the kinetic reaction data overestimate the critical pile size at temperatures below 100 degrees C.In addition, it was found that the kinetic reaction data measured by TGA can be used to determine the relative self-heating hazards for modified materials. TGA testing with towels saturated with a 0.5 N solution of cerium(IV) nitrate (Ce(NO3)4) in a 2.0 N solution of nitric acid, a 2.0 N solution of sodium nitrate in 2.0 N nitric acid and simple 2.0 N nitric acid, showed that the sodium nitrate and nitric acid treated samples reacted at the same temperatures as the untreated towels, while cerium(IV) nitrate markedly reduced the reaction temperature. These tests clearly point to the importance of the cerium(IV) ion as an oxidizing agent. Thus, the TGA testing provided in a matter of days, insights that would have required months of oven testing.