From our friends at Fabric Mart we have a good list of how fibers react to burning. These differences help us identify fiber content. VERY useful when you pull out a long held fabric from your stash and there's no label! Be sure to visit Fabric Mart and refer a friend for free shipping!
First, Precautions: Use caution during burn test. Use a metal bucket, an old tuna tin or a glass ashtray. Do not use plastic containers. Always have water nearby or have some in the bottom of your burn dish.
The Method: Cut a 1” long triangular shaped snippet off from your fabric. Hold snippet in a pair of tweezers over the dish. With either a match or cigarette lighter, the snippet should be put directly into the flame long enough for it to catch on fire.
Reaction of Fibers to the Burn Test
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.
Acrylic, Modacrylic, Polyacrylic
Made from natural gas and petroleum, they flare up at match-touch, shrink from flame, burn rapidly with hot sputtering flame and drip dangerously. Beads are hard, dark, and with irregular shapes. They continue melting after flame is removed and are self-extinguishing. When burning, they give out a strong acrid, fishy odor. Although no ash is left, their black smoke and fume are hazardous.
Threads Magazine (Taunton publishing) offers the information in a chart format that you can download here. Adapted from Threads no. 81, "Fabric Lovers Always Carry a Flame," by Mary Elliott and Elaine Zarse.
