Fire propagation apparatus

Table 8 Average heat of combustion and yields of products for polymers from the data measured in the ASTM E 2058 fire propagation apparatus...

The time to ignition as a function of incident radiant heat flux can also be measured in the ISO ignit-ability test apparatus. This apparatus and its use are described in ISO 5657. Bench-scale heat release calorimeters such as the Cone Calorimeter (Section 14.3.3.2.1) and the Fire Propagation Apparatus (Section 14.3.3.2.3) can also be used to obtain this kind of data. 

ASTM E 2058 Standard Test Methods for Measurement of Synthetic Polymer Material Flammability Using a Fire Propagation Apparatus. Annual Book of Standards, Vol. 04.07, ASTM International, West Conshohocken, PA. 

The range of toxicity test methods is bound to produce different fire conditions, and hence different toxic product yields. Four test methods (NBS Smoke Chamber, NF X 70-100, Fire Propagation Apparatus [FPA], and SSTF) have been compared, primarily from published data64 66 using the carbon monoxide yields and hydrocarbon yields (not recorded in the NFX tests), which are both fairly good indicators of fire condition, for four materials (LDPE, PS, PVC, and Nylon 6.6), at two fire conditions, well-ventilated and under-ventilated. The CO and hydrocarbon yields are shown in Figures 17.9 and 17.10. 

FIGURE 17.8 Fire propagation apparatus. (From Hull, T.R. and Paul, K.T., Fire Saf. 42, 357, 2007. With permission.)... 

This would not be problematic if standardized, reliable, reproducible, and inexpensive laboratory tests were available to estimate each of the required properties. Although several specialized laboratory tests are available to measure some properties (e.g., specific heat capacity can be determined by differential scanning calorimetry [DSC]), many of these tests are still research tools and standard procedures to develop material properties for fire modeling have not yet been developed. Even if standard procedures were available, it would likely be so expensive to conduct 5+ different specialized laboratory tests for each material so that practicing engineers would be unable to apply this approach to real-world projects in an economically viable way. Furthermore, there is no guarantee that properties measured independently from multiple laboratory tests will provide accurate predictions of pyrolysis behavior in a slab pyrolysis/combustion experiment such as the Cone Calorimeter or Fire Propagation Apparatus. 

These data were measured in the ASTM E2058 Fire Propagation Apparatus under quiescent airflow conditions for about 100 mm and 25-mm thick slab of polymethylmethacrylate (PMMA), with surface coated black [39], The experimental TRP value, TRPexp, is taken as the inverse of the slope of the linear relationship between (1/hg) / and g", for black coated surface (a = 1.0). 

Examples of the release rates of heat and products measured in the ASTM E2058 Fire Propagation Apparatus and the ASTM E1354 Cone Calorimeter, taken from Refs. [19, 41-44] are listed in Tables 11.9 and 11.10. Table 11.9 lists release rates of products and heat for polymers from parts of a minivan measured in ASTM E2058 Apparatus in normal air and 50 kW/m of external heat flux, where data are taken from Ref. [41], Table 11.10 lists heat release rates measured in ASTM E1354 Cone Calorimeter for various polymers at three external heat flux values, where data are taken from Refs. [42-44]. The HRP (A//ch/A//g) values are also listed in Table 11.10, which are obtained from the slopes of the lines representing the relationship between gch [EQ- (H-8)]-... 

Table 11.9 Peak Release Rates of Heat and Products from the Combustion of Polymers from Parts of a Minivan Measured in the ASTM E2058 Fire Propagation Apparatus"...

Data in Table 11.10 from the Cone Calorimeter indicate that the burning behaviors of polymers are similar to those indicated by the data in Table 11.9 from the Fire Propagation Apparatus. Ordinary polymers (which are thermoplastics and melt easily) have very high heat release rates in the range predicted for the liquid pool fires. For example, for the boiling liquid pool fires of PE, PP, nylon 6, and ABS, 2di values at 50 kW/m are in the range of 1133-1304 kW/m from the Cone Calorimeter (Table 11.10) and 1004-1341 kW/m from the Fire Propagation Apparatus (Table 11.9). 

The heat release rates for thermoplastics with glass fibers and charring-type thermoplastics, high-temperature polymers, and halogenated polymers from the Cone Calorimeter (Table 11.10) are in the range predicted for the burning of solid polymers and similar to those from the Fire Propagation Apparatus (Table 11.9). 

The NFPA 318 deals with the protection of clean rooms whereas the FMR 4910 and UL 2360 deal with the flammability of polymers for the clean rooms. In the FMR 4910 test standard, ASTM E2058 Fire Propagation Apparatus (FPA) [31] is used, whereas ASTM El354 Cone Calorimeter [36] is used in the UL 2360 test standard. Both test standards evaluate the fire propagation and smoke release behaviors of the polymers. Eor polymers for which fire propagation behavior cannot be defined clearly, both test standards use a large-scale parallel panel test [40, 63, 78]. Figures 11.12 and 11.13, discussed in an earlier section, illustrate the parallel panel test. 

Figure 11.15. Relationship between the generation rate of polymer vapors in combustion in normal air at 50 kW/m and FPl determined for fire propagation in 40% oxygen concentration. Data were measured in our laboratory in the ASTM E2058 Fire Propagation Apparatus [21, 22, 40, 80-86].

Tests performed in the apparatuses specified in the three standards listed above, i.e., ASTM E 1321/ISO 5658 (LIFT apparatus), ASTM E 1354/ISO 5660 (cone calorimeter), and ASTM E 2058 (fire propagation apparatus) provide complete set of fire properties for the assessment of ignition behavior of polymer products. These apparatuses also provide data in a format that is useful for the engineering methods in the performance-based lire codes. 

The heat of complete combustion is measured according to ASTM D 5865/ISO 1716 test methods [45,46]. The release rates of material vapors, heat, and various chemical compounds (including smoke) are measured according to ASTM E 906 (the Ohio State University Heat Release Rate, OSU-HRR, Apparatus), ASTM E 2058 (fire propagation apparatus) and ASTM E 1354/ISO 5660 (cone calorimeter) [45,46]. Smoke released in flaming and nonflaming fires of materials is also characterized... 

Fig. 29. Commercial version of the fire propagation apparatus. Photo Courtesy of Fire Testing Technology 2004.

The fire propagation apparatus is similar to the cone calorimeter and can be used to obtain the same types of measurements. However, there are some significant differences that are briefly summarized below ... 

FPA). A photograph of a commercial version of the fire propagation apparatus is shown in Figure 29. 

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