Flammability testing covers several different testing protocols and methods intended to measure a material’s vulnerability, including its susceptibility to an ignition source, its propensity to combust, and the rate at which it will burn when ignited.
Under fault or overload conditions, component systems or individual plastic parts may reach temperatures which causes them to deform, melt, or possibly ignite. Consideration must also be given to whether adjoining materials could aggravate these conditions or be ignited by a failing plastic material.
To limit failure consequences, compliance agencies have established performance criteria that can be used during material selection and part design.
The burning behavior of plastics is not just a material characteristic. Part design and nominal wall thickness are key factors in flammability certification.
Cotton is a cellulose fiber. It burns and may flare up when lit. No melted bead is left by it. After burning, it continues to glow. It gives out a smell like that of a burning paper. The smoke is gray or white. The ash is fine and soft and can be easily crumbled.
Hemp：A cellulose fiber, burns quickly with bright flame. It leaves no melted bead and after burning no sign of flame is seen. It smells like burning leaves or wood. The ash is gray and smoke has no fume hazard.
Jute：Also a cellulose fiber, doesn’t shrink from flame. Other characteristics are similar to those of hemp fabric.
Linen (Flax)：A cellulose fiber, it takes longer to ignite. It is easily extinguished by blowing on it. Other properties are similar to hemp and jute.
Rayon：Is a manufactured cellulose fiber. It burns without flame or melting and may flare up.
Unless there is a fabric finish, it doesn't leave any bead. After the flame is removed, it may glow a bit longer than cotton. It smells like burning paper and leaves soft, gray ash. It's smoke is a little hazardous.
Silk：Is a protein fiber which burns slowly and curls away from the flame. It leaves a dark bead which can be easily crushed. It is self-extinguishing and leaves ash that is a dark, gritty, fine powder. It smells like burned hair or charred meat. It gives out little or no smoke and the fume has no hazard.
Wool：Is a protein fiber which burns slowly. It sizzles and curls away from flame and may curl back onto fingernail. It leaves beads that are brittle, dark, and easily crushed. It is self-extinguishing and leaves harsh ash from crushed bead. It gives out a strong odor of burning hair or feathers. It gives out dark smoke and moderate fume.
Acetate, Triacetate：Is a protein fiber which burns quickly and can flare even after flame is removed. The bead is hard, brittle, and can't be crushed. It melts into a very hot bead and drips very dangerously. No ash is left by it and the smell is like hot vinegar or burning pepper. It gives out black smoke and the fume is hazardous.
Nylon, Polymide：Are made from petroleum. Due to their fabric finish, they quickly burn and shrink to flame. The beads are hard, grayish and uncrushable. After flame, they burn slowly and melt. They are self-extinguishing but drip dangerously. Their odor is like celery and they leave no ash but the fume is very hazardous.
Polyester：Is a polymer produced from coal, air, water, and petroleum products. It burns quickly and shrinks away from flame, may also flare up. It leaves hard, dark, and round beads. After the flame, it burns slowly and is not always self-extinguishing. It has a slightly sweet chemical odor. It leaves no ash but its black smoke and fume are hazardous.