Calorimeter testing

Figure 12-19. The PHI-TEC II adiabatic calorimeter Test cell and calorimeter in main pressure vessel rated for use to 138 bara. (Source Hazard Evaluation Laboratory Ltd.)...

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. 

Once ignited they produced considerable amounts of heat and smoke. Flame retarded flexible PU foams became available in 1954-55, i.e. within a few years of flexible PU foams becoming available in commercial quantities(22). These FR PU foams contained trichloroethyl phosphate or brominated phosphate esters and resisted ignition from small flame sources. Unfortunately they may burn when subjected to a larger ignition source or when covered by a flammable fabric and may then produce as much heat and more smoke than the standard grade of PU foam(3). This was identified by UK room tests in the early 1970 s and has been confirmed more recently by furniture calorimeter tests at the NBS(21). 

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. 

A laboratory test has shown that the reaction will not result in a two-phase relief. Thus a vapor relief system must be designed. Furthermore, calorimeter tests indicate that the maximum self-heat rate is 40°C/min. The physical properties of the material are also reported ... 

Although the tunnel test is widely accepted, conditions and orientations involved are not those normally found in installed insulations. New laige-scale tests have been developed the results can be taken to represent actual performance more closely. Such tests include the International Conference of Building Officials (ICBO) and ASTM E603 full-scale room tests, ASTM E108 roofing test, the UL roof deck construction test, the Factory Mutual Calorimeter Test, and both alaige- and small-scale comer test. 

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. 

Furniture calorimeters were developed in the 1980s in several laboratories to obtain this kind of data.70 71 The first furniture calorimeter test standard was published in 1987 in the Nordic countries as NT Fire 032. Furniture calorimeter test standards have been developed by ASTM for chairs, mattresses, and stacked chairs. The corresponding designations are ASTM E 1537, ASTM E 1590, and ASTM E 1822, respectively. The California Bureau of Home Furnishings and Thermal Insulation (CBHFTI) developed California Technical Bulletins (CAL TB) 133 and 603. These documents describe fire test procedures to qualify seating furniture and mattresses, respectively, for use in public occupancies in California. CAL TB 603 has been superseded by the Federal CPSC standard 16 CFR 1633. The primary difference between the various chair and mattress tests is the ignition source. 

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... 

A number of modern full-scale fire test methods have been developed for products, relying on heat release rate measurements, such as those involving testing of upholstered furniture (ASTM E 153792 and CA TB 13391), mattresses (ASTM E 1590,85 CA TB 129,82 CA TB 603,88 16 CFR 1633,19 and ASTM F 1085 [Annexes A1 and A3]171), stacking chairs (ASTM E 1822172), electrical cables (ASTM D 5424,173 ASTM D 5537,174 and UL 1685123), plastic display stands (UL 1975),175 other decorative items (NFPA 289,176 a generic furniture calorimeter test), electrical equipment (UL 2043),120 or wall-lining products (NFPA 265,116 NFPA 286,115 ASTM E 2257,177 and ISO 9705178). In fact, room-corner tests are now being used in the codes, as alternatives to replace the... 

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... 

Janssens, M.L., Database on full-scale calorimeter tests on motor vehicles, HAR-AAA TC Meeting, Detroit, MI, October 23-24, 2006. 

Material Styrofoam cup (calorimeter), test tubes, balloons, measuring cylinder, balances, thermometer white copper sulfate. 

Figure 25 Schematic diagram of room calorimeter test (ISO 7905). 1. Room. 2. Gas burner ignition source. 3. Room exit door. 4. Hood. 5. Fire gas mixing baffles. 6. Gas sampling, temperatures, and velocity probes, smoke measuring sensors. 7. Exhaust fan. Note Furniture calorimeter is similar but without room. Test. specimen is burned directly under hood (NT Fire 032).

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