COTTON  410

Grown and produced at varying quality levels cotton can either be grown with pesticides and harmful chemicals in the clothing production process or directly introduced at the crop level. There is also organic cotton production and clean clothing manufacturing processes that do not utilize as many harmful substances in or around the cotton fibers. These influences may affect the temperature at which the fabric ignites and starts to burn.
Burning Point: 410 degrees Fahrenheit (210 C)
Autoignition Temperature: 764 degrees Fahrenheit (407 C)
Variables: These numbers are significantly lower if the cotton is oily or is soaked in or contains a more flammable substance in the material. Cotton blends or waxed cotton will also change the burning point and safety measures one must take with the material. Along with available air flow, fire requires oxygen and lowering or increasing the surrounding oxygen levels will change the temperature at which the material will catch flame. Less oxygen means the temperature must go higher to compensation, and vice versa - with open air flow the numbers above are more accurate.

SILK 298

A natural protein fiber from animals and genuine natural silk will burn at much lower temperatures than other fabrics. Silk is slow to ignite and scorches rather than burns at its ignition temperature.
Burning Point: 298 degrees Fahrenheit (148 C)
Variables: Silk blends introduce other ingredients that can change the way the material burns and at what temperature the material burns. Pure silk that generally scorches rather than burns with a sustained flame may ignite and burn with a flame if mixed with other types of fabric that exhibit different properties.

WOOL 1058

A natural fiber largely composed of keratin protein. Wool can absorb 33% of its weight in water and maintains a high level of nitrogen, around 17% nitrogen to be specific. Nitrogen is naturally flame resistant and water further elevates the temperature required to burn wool. Wool does not sustain an open flame for long, wool especially as thread will shrink from the heat source and smolder while curling into charred ends.
Burning Point: 1058 degrees Fahrenheit (570 C)
Variables: Available airflow and whether the fabric is damp or dry in storage. Wet wool stored in bales causes metabolic bacterial reactions which subsequently increases the heat inside of the bales, a bale of wet wool can reach 158 degrees Fahrenheit (70 C). This temperature is not hot enough to spark spontaneous combustion that is claimed by some transporters and wool producers, however it is enough to rot and wear away at the fabric during storage.

LINEN 460

A natural fiber textile made from the flax plant, linen fabric is also generally composed in a plain weave, i.e., the linen weave. Linen is a bast fiber from the flax plant, a plant-based cellulose fiber. Linen burns quickly and maintains an afterglow once the open flame has dissipated. The flame will burn the entire piece of fabric.
Burning Point: 460 degrees Fahrenheit (237 C)
Variables: The size of the linen piece and the weave and thickness of the linen textile will influence the burn time and open flame size.

LEATHER 1000

Real animal leather chars rather than burns and is naturally flame resistant up to a high temperature. Leather will curl and eventually char but it hardly burns and does not sustain open flame well.
Burning Point: 1000 degrees Fahrenheit (537 C)
Variables: Oily leather will burn more easily and quickly than properly dried or aged leather. The source of heat, direct flame rather than elevated temperature environments such as an oven. Leather is difficult to burn.

SEMI-SYNTHETIC FABRIC

RAYON  788

Is a semi-synthetic fiber made from regenerated cellulose fibers. Made from natural sources the materials are chemically processed into rayon which makes it a semi-synthetic semi-natural fabric. Rayon burns without a visible flame but does not melt.
Burning Point: 788 degrees Fahrenheit (420 C)
Variables: Rayon is a class of textiles, most commonly made with wood pulp as the base natural ingredient, this is subject to change and also the type of wood can change - which may or may not alter the melting points observed.

SYNTHETIC FABRICS

Synthetic fabric generally melts rather than burns.

POLYESTER 482

Synthetic polymers with ester groups, polyester melts rather than burns. Polyester is a kind of plastic (polyethylene terephthalate). Polyester melts but does not sustain an open flame.
Melting Point: 482 degrees Fahrenheit (250 C)
Autoignition Temperature: 842 degrees Fahrenheit (450 C)
Variables: Duration of exposure to high heat sources will influence the melting of the textile. Also, the thickness of the textile and if it is blended or arranged with other materials will ultimately affect the melting rate and melting temperature.

NYLON 428

Is a class of thermoplastic polymers used to make artificial fabric. There is a grade numbering system in relation to the chemical structure of nylon (the most common being 6, 66, 11 and 12). Nylon melts rather than burns.
Melting Point: 428-554 degrees Fahrenheit (220 C to 290 C)
Variables: The temperature ranges based on the chemical structure of the nylon, i.e., the nylon number grade. For example, nylon 6 melts at the low end of the spectrum, 220 C or 428 Fahrenheit.

Various fabrics burn or melt at different temperature levels and the accuracy of these numbers is in some part dependent on the manufacturer, the manufacturing processes and materials/ingredients used to make the final product and any blending of fabrics or fabric treatment the manufacturer utilizes.