The Finnish Defence Forces along with VTT Technical Research Centre of Finland conducted a series of experiments in 1983 to find out the maximum amount of heat radiation that some textiles and clothing items can be subjected to without completely destroying them. I find the information they gathered rather interesting to our purposes as often one has to spend considerable amount of time near a fire during winter time.
I'm not going to reproduce the original 52 page research paper here but I'll try to find the most interesting textiles and items and reproduce the findings. If you thing I'm missing something, please post your question here on this thread. The materials were tested under 5, 10, 20 and some also under 40 and 60 kW/m² of heat radiation. The first rating corresponds roughly to 100 - 200°C depending the distance from the source, the second one to 200 - 300°C and the last ones from 300 to 1200°C. The average solar radiation to the surface of Earth is around 1 kW/m² and 4 kW/m² is enough to cause second-degree burns to the skin within 30 seconds of exposure.
Some of the tested fabrics were:
1) 370 g/m² 100 % CO sateen with camouflage pattern. Obtains a brown tint at 20 kW/m².
2) 370 g/m² 70 % CO/30 % PE with camouflage pattern. A brown tint at 10 kW/m².
3) 550 g/m² 85 % WO/15 % PA brushed twill. A brown tint at 10 kW/m². Charring and shrinking at 20 and 40 kW/m².
4) 100 % WO sweater. A brown tint at 10 kW/m². Charring at 20 and 40 kW/m².
5) 100 % PE pile lining. Shrinked at 10 kW/m². Burnt through at 20 kW/m².
6) 100 % PE wadding. Shrinked at 10 kW/m². Melted at 20 kW/m².
7) Tanned leather boot. Shrinking at 5 and 10 kW/m². Shrinking and tearing at 20 kW/m². Broke down at 40 kW/m².
8) Vulcanized natural rubber boot. Some surface damage at 10 kW/m². Charring at 20 kW/m².
9) 330 g/m² 100 % AR. Hardens at 20 kW/m². Shrinking, charring and tears at 60 kW/m². The only one capable of withstanding 60 kW/² for some time.
When comparing fabrics of same thickness, wool ranks the best after aramid and polyester is the worst. However a thick and dense cotton fabric can be better than a thin wool one as we can see in the case of the wool sweater. Rubber is considered better than leather. In previous Finnish tests a 100 % wool fabric of similar weight than the blend fabric in this test was found to withstand the effects of napalm for some time.
I'm not going to reproduce the original 52 page research paper here but I'll try to find the most interesting textiles and items and reproduce the findings. If you thing I'm missing something, please post your question here on this thread. The materials were tested under 5, 10, 20 and some also under 40 and 60 kW/m² of heat radiation. The first rating corresponds roughly to 100 - 200°C depending the distance from the source, the second one to 200 - 300°C and the last ones from 300 to 1200°C. The average solar radiation to the surface of Earth is around 1 kW/m² and 4 kW/m² is enough to cause second-degree burns to the skin within 30 seconds of exposure.
Some of the tested fabrics were:
1) 370 g/m² 100 % CO sateen with camouflage pattern. Obtains a brown tint at 20 kW/m².
2) 370 g/m² 70 % CO/30 % PE with camouflage pattern. A brown tint at 10 kW/m².
3) 550 g/m² 85 % WO/15 % PA brushed twill. A brown tint at 10 kW/m². Charring and shrinking at 20 and 40 kW/m².
4) 100 % WO sweater. A brown tint at 10 kW/m². Charring at 20 and 40 kW/m².
5) 100 % PE pile lining. Shrinked at 10 kW/m². Burnt through at 20 kW/m².
6) 100 % PE wadding. Shrinked at 10 kW/m². Melted at 20 kW/m².
7) Tanned leather boot. Shrinking at 5 and 10 kW/m². Shrinking and tearing at 20 kW/m². Broke down at 40 kW/m².
8) Vulcanized natural rubber boot. Some surface damage at 10 kW/m². Charring at 20 kW/m².
9) 330 g/m² 100 % AR. Hardens at 20 kW/m². Shrinking, charring and tears at 60 kW/m². The only one capable of withstanding 60 kW/² for some time.
When comparing fabrics of same thickness, wool ranks the best after aramid and polyester is the worst. However a thick and dense cotton fabric can be better than a thin wool one as we can see in the case of the wool sweater. Rubber is considered better than leather. In previous Finnish tests a 100 % wool fabric of similar weight than the blend fabric in this test was found to withstand the effects of napalm for some time.