Effect on Flammability, Ignition, Flame Spread

Clearly, porous WPC boards, having low density and having their pores filled with air oxygen, would maintain flame spread much more easily than the higher density boards. 

The literature has apparently no data on the effect of density of WPC on flammability, but the issue is quite obvious. Table 6.7, showing ignition data with respect to several wood species, illustrates the concept. 

One can see how much density of the materials effects ignition time. The lower the density of materials, the lower the ignition surface temperature. 

TABLE 6.7 Flammability data for selected wood species [2]. Data are determined using ASTM E 906 

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