PRACTICAL - 5, Fiber Identification Burning Test

 

BANARSIDAS CHANDIWALA INSTITUTE OF HOTEL MANAGEMENT & CATERING TECHNOLOGY

Course Name:  BHMCT                            Semester: 3^rd                 Paper Code: BHCT- 257

Practical: Fiber Identification Test-Burn Test                                     

 

Objective: Students will be able to identify fibre quality with burning test.

Burning Test of Textile Fiber | Flammability Test of Textile Fiber | Fiber Identification Through Burning Test

Fabric Identification is done with a simple fabric burn test or fiber burn test. A flammability test is best to know the identification of fabric. To recognize the composition of fabrics by the burning test, the sample of fiber, yarn of the fabric should be moved slowly towards a small flame and the reaction to heat carefully observed. One end of the sample should be put directly into flame to determine its burning rate and characteristics. The burning odour should be noted and the characteristics of the ash such as amount, form, hardness and colour should be examined.

                                                           To identify fabric that is unknown, a simple burn test can be done to determine if the fabric is a natural fiber, manmade fiber, or a blend of natural and manmade fibers. The burn test is used by many fabric stores and designers and takes practice to determine the exact fiber content. However, an inexperienced person can still determine the difference between many fibers to "narrow" the choices down to natural or manmade fibers. This elimination process will give information necessary to decide the care of the fabric.

PRECAUTIONS

All fibers will burn! The burning test should be done with caution. Use a small piece of fabric only. Hold the fabric with tweezers, not your fingers. Burn over a metal dish with soda in the bottom or even water in the bottom of the dish. Do not use plastic containers. Always have water nearby or have some in the bottom of your burn dish. Some fabrics will ignite and melt. The result is burning drips which can adhere to fabric or skin and cause a serious burn. Use caution during burn test.

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. Fibers can also be identified through the smell of the smoke it gives off in burning, and the ash or melted bead that remains after it has burned. Some of the fabrics are blends, and the blend of fibers may make the burn test a rather unreliable test for fiber content. Moreover, some fabrics have chemical finishes and sizings applied to them that will change the way they burn, making the burn test further unreliable.

IDENTIFICATION OF FIBRES THROUGH BURNING TEST

Cotton

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/leaves. 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. It smells like burning leaves or wood. The ash is gray and smoke has no fume hazard. 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

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

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

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

It 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

They are made from petroleum. Due to their fabric finish, they quickly burn and shrink to flame. The beads are hard, grayish and un-crushable. 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

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

These are 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.

LIMITATION OF BURNING TEST

It is apparent that many fibers have similar burning reactions that might cause doubt and occasional confusion.

BURNING CHARACTERISTICS

Burn Test Chart. Fabric Identification - The Burn Test

The reaction of fibers to heat from an open flame is a useful guide in identification of fibers.

Types of fabric	Reaction to flame	Burning behaviour	Odour of flame	After the flame is over	Type of Ash
Cotton, Hemp, Ramie	Doesnot shrink away from flame; Ignites easily on contact with flame	Burns rapidly with a yellow flame and light grey smoke.	Burning paper.	Continues to burn, there is an after glow.	Soft Grey powdery smooth ash
Linen	Doesnot shrink away from flame; Ignites easily on contact with flame	Burns rapidly with a bright yellow flame and light grey smoke.	Burning paper.	Continues to burn, there is an after glow.	Soft Grey powdery smooth ash
Rayon, Tencel	Doesnot shrink away from flame; Ignites easily on contact with flame	Burns rapidly with a yellow flame and light grey smoke.	Burning wood or paper.	Burns slowly without flame with slight melting	No ash
Wool	Shrinks away from flame.	Burns slowly with an orange colour but doesnot melt; small flickering flame	Strong odour of Burning hair or feather	May self extinguish ie it burns itself out	Crushable black bead that turns to ash.
Silk	Shrinks away from flame.	Burns slowly sizzles but doesnot melt	Burning hair.	May self extinguish	Crushable black bead that turns to ash.
Acrylic, Olefin	Melts and pulls away from the flame.	Melts and burn rapidly with hot sputtering black flame	Acrid Chemical odour (Fishy odour)	Continues to burn and melt.	Forms irregular small beads in black /tan
Modacrylic	Melts and pulls away from the flame.	Difficult to ignite; Melts and burn	Chemical odour	Self extinguishes with white smoke.	Forms small hard beads in black
Spandex	Melts but doesnot pull away from the flame.	Melts and burn	Musty Chemical odour	Continues to burn and melt.	Soft sticky black ash.
Polyester	Melts and pulls away from the flame.	Melts and burn with black smoke	Sweet chemical odour	Continues to burn and melt.	Forms small hard beads in cream and later tan colour
Acetate	Melts and pulls away from the flame.	Melts and burn with yellow flame	Acrid, harsh, sharp odor.	Continues to burn and melt.	Forms small beads
Nylon	Melts and pulls away from the flame.	Melts ; bubbles as it burns	Acrid, harsh, sharp odor.	Continues to burn and melt.	Forms small beads

VIDEO LINKS

1. https://youtu.be/xmKKvepQujo
2. https://youtu.be/kb4tCcnA6jo
3. https://youtu.be/-SriB05FLU4
4. https://youtu.be/oDXOl4UbSqU
5. https://youtu.be/IYPemQ5ybVU

PPT

Practical 5 Fiber Identific... by Deepak Chhikara