Cone calorimeter tests

The small scale fire tests were, the Scandinavian "box test", Nordtest NT-FIRE 004, the DIN 53436-test and a cone calorimeter test. The study covered six different wall lining materials. 

The same hazard concept could, potentially, be used for full scale tests, multiplying the total heat released, per unit surface exposed, by the maximum smoke obscuration. This is the basis for the magnitude smoke hazard (Smoke Haz.), shown in Table II. It is of interest that smoke hazard results yield the same ranking as mass of soot formed. Cone calorimeter tests are being planned with the same materials used in the full scale tests to investigate the usefulness of this concept. 

There is evidence to show that the particle size of the filler also plays a significant role in flammability resistance. For example, below a certain particle size (about 1-2 pm), in many tests, including oxygen index, aluminum hydroxide shows enhanced fire-retarding performance,34 which may be associated with the rate of filler decomposition and/or with the formation of a more stable ash. However, it has been found that the particle size effect is absent, or less evident, in the cone calorimeter test.35 Similarly, particle size reduction has been shown to enhance fire retardancy in magnesium hydroxide-filled PP in this case, samples were characterized by the UL94 test.36 This raises the question as to whether further reductions in particle size to the nanoscale will lead to an additional increase in flammability performance, and perhaps enable filler overall levels to be significantly reduced. This aspect is considered in a later section. 

Borosilicate glass is a range of glasses based on boric oxide, silica, and a metal oxide. It has excellent thermal shock resistance and chemical resistance. A recent patent claimed the use of borosilicate glass powder (50-100 phr) in conjunction with expandable graphite (100 phr) or vermiculite in polyolefin, epoxy, or elastomers to achieve good fire retardancy (as evidenced by the Cone Calorimeter test at 35 kW/m2).99... 

In the work of Wilkie et al.,55,56 oligomers of styrene, vinylbenzyl chloride, and diphenyl vinyl-benzylphosphate and diphenyl vinylphenylphosphate (DPVPP) have been prepared and reacted with an amine and then ion-exchanged onto clay. The resulting modified DPVPP clays have been melted blended with polystyrene and the flammability was evaluated. XRD and TEM observations proved the existence of intercalated nanocomposite structures. Cone calorimeter tests have shown a substantial reduction in the PHRR of about 70% in comparison with pure PS. According to the authors, this reduction was higher than the maximum reduction usually obtained with PS nanocomposites. Other vinylphosphate modified clay nanocomposites were also elaborated. The reduction in PHRR was greater with higher phosphorus content than for DPVPP. Consequently, the reduction in PHRR seemed attributed to both the presence of the clay and to the presence of phosphorus. 

FIGURE 12.6 Photos of the LDPE/EVA filled samples (a) Hy60, and (b)Hy/MMT50 after cone calorimeter test. (From Laachachi, A. et al., Polym. Degrad. Stabil., 89, 344, 2005.)... 

Regardless of the nature of these nanotubes, their dispersion state in the host polymer is crucial and its improvement is a challenge to achieve the best lire performance of the corresponding nanocomposites. For example, Kashiwagi et al.9 have shown that in PMMA well-dispersed SWNTs led to a strong decrease in PHHR in cone calorimeter tests, while poorly dispersed SWNTs did not modify HRR in comparison with pristine PMMA. 

The THR(t) during a cone calorimeter test is the integral of the HRR with respect to time—the total heat output up to that point. The THR at the end of the test is the THE and is, therefore, the fire load of the specimen in the cone calorimeter fire scenario. The THE and the HRR are mathematically related, but monitor quite independent fire hazards. 

Messerschmidt B, Van Hees P, Wickstrom U. Prediction of SBI (single burning item) test results by means of cone calorimeter test results. Interflam 1999, Proceedings of the Eighth International Conference. Interscience Communication Limited London, 1999 pp. 11-22. 

A schematic view of the sample holder used in cone calorimeter tests. 

The UFA shown in Figure 19.22 has a controlled oxidizer atmosphere and representing burning on a 100 mm diameter sample in horizontal orientation in a more realistic way than the standard cone calorimeter. Tests were conducted in over-ventilated fires but at reduced oxygen concentration (15%, 17.5%, and 21%) in the oxidizer stream. Because of in-depth absorption of the sample under infrared radiation, samples with and without a layer of carbon black coating were tested. 

L is the latent heat of pyrolysis, which can be determined from DSC tests or by considering the energy balance at the peak MLR in the cone calorimeter tests... 

ASTM E 84 Steiner tunnel test, thus generating more useful results. Figure 21.13 shows a room-comer test layout. The cone calorimeter fire-performance index (with tests conducted at 50kW/m2)179 was shown to be a good predictor of time to flashover in FAA full aircraft fires170 180 and in the ISO 9705 room-corner test.181 In addition, the same cone calorimeter tests, but using only heat release criteria, have been shown to have almost perfect predictability of ISO 9705 room-comer test rankings.181... 

CCT cone calorimeter test GGNP current gross national product... 

Fire parameters (cone calorimeter test) External heat flux 60 kW m (44)... 

Nevertheless, some authors have provided some evidence of a flame inhibition effect of phosphorus. Schartel et al. have measured the EHC of epo y resins in a PCFC i.e. corresponding to complete combustion) and in a cone calorimeter. Epojy resins containing DOPO covalently linked to the network have been studied. All thermosets exhibited the same EHC in a PCFC (approximately 24 kJ g ), but in cone calorimeter tests the composites prepared from the phosphorus-containing resins (with 60 vol% of carbon fibers) exhibited a significantly lower EHC than the composite prepared from the phosphorus-free epoxy resin. In this study, a clear flame inhibition effect was evidenced. 

Zhang et al. [31] studied fire-retardant properties of PP/IFR/LDH nanocomposites, which were comprised by a typical intumescent flame retardant (IFR) system and LDHs with different bivalent metal cations. The results of pk-HRR, pk-MLR, pk-EHC, and ignition time (IT) obtained from the cone calorimeter tests of various samples were listed in Table 8.1 [31]. It could been seen from Table 8.1 that the IT values of PP/IFR/LDH samples with different divalent metal cations of Zn, Mg, Cu, and Ca were 55, 55, 54, and 52 s, respectively, which are longer than 48 s of the PP/IFR sample without LDH. These data showed that the PP/IFR samples with LDHs are obviously harder to ignite than the sample only with the IFR. 

Cone calorimetry (CC) is one of the most effective medium-sized polymer fire behavior tests. The principle of cone calorimeter experiments is based on the measurement of the decreasing oxygen concentration in the combustion gases of a sample subjected to a given heat flux, in general from 10 to 100 kW/m [83]. Figure 4 illustrates the experimental set-up of a cone calorimeter. Standardized in the United States (ASTM E 1354), the cone calorimeter test is also the subject of an international standard (ISO 5660). 

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