Journal of Fire Sciences

The oxidative decomposition of a green-and-white checkered cel lulosic fabric, designated as FOR-1, comprised of four different yarns, was stud ied using TPR/GC and DSC techniques. Containing different alkali metal ion (AM ⁺) and dye concentrations, these four yarns experienced directionally selec tive smolder behavior during cigarette ignition tests. Measurements were per formed on the integrated fabric and on each of the four yarns. A model explaining the anisotropic smolder and high-temperature behavior of this fabric was developed.

The decomposition of a heavily bleached, cellulosic sailcloth was also studied. The results showed an increase in the fabric degradation/cleavage rate com pared to unbleached #6 cotton duck. The DSC spectra of the sailcloth, however, did not significantly differ from that of the washed cotton duck. Similar thermochemical behavior was observed in the blue-dyed denim fabric contain ing 1500 ppm potassium; the low-temperature DSC behavior of this denim was also found to be similar to that of undyed, nicotine-treated cotton duck studied in Reference [4]. These results support a model comprising the mechanisms of smolder and combustion of colored cellulosic fabrics.

The lower and the upper flash points of mixtures containing non-flammable liquids were measured by a modified Seta-flash closed-cup tester. The shape of the concentration-temperature region of flash depended on the components of the mixture in solution. Concentration regions for a flash were calculated from the temperature regions of flash and compared to the flammability diagram.

We present a theoretical method for calculating both the lower and upper flash points by liquid mixture thermodynamics, and the flammability diagram. The experimental values for the methanol/water mixture agreed with calculated values, but disagreed for halogenated hydrocarbon mixtures. The difference be tween the calculated and experimental values is from a flame-suppressing effect in the gas phase, which is distinct from the thermodynamic effect on solution. We discuss the magnitude of this flame-suppressing effect exhibited by halogenated hydrocarbons in the gas phase.

Four samples of pipeline wax from a North Sea crude oil pipeline have been examined in a microcalorimeter across a range of temperatures. The samples, which weighed a little under a gram, gave heat-release rates up to about 20 μW, and the initial temperature history is such that there is a small amount of melting which is manifest as a negative microcalorimeter signal. Esti mated activation energies for the oxidation are of the expected order of magni tude, though a little low.

This paper describes experiments and results that have been ob tained from a pyrolysis/gas chromatography/mass spectroscopy study on chlori nated polyvinyl chloride (CPVC-65% Cl) containing two commercially available plasticisers, namely, DOP and Santicizer 2148 with and without modest amounts of an iron (III) smoke suppressing compound. Careful analysis of the mass spectra obtained from the pyrolysis products has shown that the smoke suppressing effect of basic iron (III) oxide (FeOOH) is essentially the result of two sets of chemical reactions. This iron compound reacts with the CPVC poly mer and the plasticisers present. Increased amounts of char formed from the CPVC combined with changes in the path of decomposition during pyrolysis of both plasticisers to give fewer smoke precursor molecules resulted in a signifi cant reduction in smoke formation.

This work deals with the fire retardancy of polypropylene (PP)/thermoplastic polyurethane (TPU)/ammonium polyphosphate (APP) intu mescent blends, using TPU with different chemical compositions and struc tures. The influence of the chemical nature of the polyol used in the synthesis of the TPU on the fire resistance of materials is discussed. Moreover, smoke pro duction from combustion of the blend and mechanical properties (elonga tion/stress relation) of the polymeric materials are studied. Improved flame retarded (FR) materials with very different mechanical properties according to the composition of the TPU can be formulated.