Fabric Flammability

Fabric Flammability stands for how easily a fabric can ignite, tends to burn and propagates to flame. This parameter depends upon yarn type, fabric weight and structure, and finishes applied to the textile. It is evaluated by vertical, horizontal, and 45-degree angle tests of flammability, also called textile burn test.

It is estimated by the U.S. Consumer Product Safety Commission (CPSC) that more than 4,000 people suffer injuries, and an average of 150 people are fatalities per year due to clothing flammability.

In May 2019, a famous textile brand, American Apparel, recalled 10,000 articles about children’s sleep sacks due to the risk of flammability. This lot failed to meet the criteria of the US Standard for the safety of children’s sleepwear and night dresses.

“Allianz,” a well-known insurance company, states that this recall cost more than $12 Million. Fabric tests of flammability help researchers and manufacturers develop better flame-retardant products and ensure the quality of textiles before shipment.

Why Flammability Test is Important to Conduct?   

The flammability test in the cloth testing laboratory describes the behaviour of burning textile products, giving a clear idea of whether they meet customer standards.

It describes how easily a fabric can catch fire, sustain combustion, or propagate to flame. The self-extinguishing behaviour of flame retardant fabrics gives researchers a better idea of further developments.

By performing this test on a fabric lab test machine, manufacturers can take necessary action to ensure the quality of clothing before shipment.

Which Factors Influence Fabric Flammability?  

Natural fabrics are mostly inherently flammable. These are treated with different flame retardant finishes to make natural fibres less flammable.

Experiments have shown that fabrics with more weight are less flammable, even made of natural fibers, than thin and sheer fabrics.

Sheer fabrics have more space in threads, which contain more oxygen and support ignition and combustion. Let’s see the factors that have a direct impact on fabric burning.

1. Fabric Type 

Fabric type is a major parameter in the burning of clothing. For example, a fabric made of cellulosic fibres like cotton or viscose burns rapidly as compared to wool.

A survey by Gandhi and Spivak (1994) shows that excessive use of cotton in upholstery furniture causes easy ignition. That’s why researchers develop special finishes for fibres to make them fire retardant.

Wool has a high weight and more moisture content, which gives self-extinguishing characteristics. Its ignition temperature is very high, around (570ºC~600ºC).

A blend of wool and flame-retardant fibres like Kevlar designs flame-retardant fabrics for firefighters and isolation purposes.

Thermoplastic fibres are less flammable than cotton. Like polyester and nylon, they shrink before ignition. However, a blend of cotton and polyester is more explosive than a single cotton yarn, which burns rapidly and emits more heat than all other cellulosic fibres.

2. Fabric Density & Structure

Dense and heavy textiles do not burn quickly in the textile lab. Its ignition is quite difficult. Similarly, tightly woven and more packed knitted fabrics do not ignite easily.

Koresh (1996) performed an experiment by taking 25 fabrics with different weights and weave structures. He projected these fabrics onto a flame and noticed the burning behaviour.

Physical testing of fabric showed that lighter fabrics burn faster than dense and heavy-weight clothes. This is due to the presence of more oxygen in thin and sheer fabrics than in dense fabrics. However, high-weight textiles with raised surfaces can easily withstand fire.

3. Flame Retardant Finishes

Collier & Epps developed fire retardant finishes in 1998. These finishes reduce the emission of gases that support the burning of fibre. Kadolph & Langford, in 1998, made finishes for synthetic textiles as well as cellulosic fabrics.

Chemically treated fabrics are less likely to ignite, but they have some drawbacks. FR-finished clothes tend to pale yellow with time. FR finishes make the fabric stiff and hard and reduce the tear strength.

The application of FR finishes also increases the cost of production. Some FR finishes lose their characteristics after washing, which becomes more risky because the customer will not be aware of this issue.

Fabric Flammability Testing Methods 

There are three methods to measure the flammability of fabric.

1. Vertical Flammability Test
2. Horizontal Flammability Test
3. 45 Degree Angle Flammability Test (16 CFR part 1610)

Normally, vertical testing and 16 CFR part 1610 are used, so let’s examine both testing methods.

Vertical Flammability Test  

Vertical flammability is a strict test used to evaluate children’s night dresses and sleepwear. It is performed to meet the requirements of 16 CFR 1615 and 16 CFR 1616.

There are 10 specimens cut from the testing fabric of size 10” × 3.5 “inches. These specimens are put in a desiccator to remove moisture from the samples because moist or wet samples will not give us accurate results.

After drying the specimen completely, it is mounted in the holder vertically and subjected to a flame from the lower edge of the specimen for 03 seconds. After that, we will see the length of fabric that has been burned or damaged. It is called the char length.

The average char length of 10 specimens should be less than 07 inches. The char length should not be 10 inches, even for a single specimen from all 10 samples.

45 Degree Angle Flammability Test (16 CFR part 1610) 

This test evaluates the flammability of all textile clothing and apparel, except children’s sleepwear, hats, gloves, shoes, and interlinings. To perform this test, 10 specimens of 6” × 2” inches are cut.

Similarly to vertical flammability testing, all specimens are dried by placing them in a desiccator. Once the specimens are dried, we will start the testing. Firstly, the specimen is mounted in the holder at a 45-degree angle.

After that, it is contacted with a flame for 1 second. When ignition starts, the flame is removed, and we will monitor the time to burn the entire length of 6 inches.

The standard period for the flame to spread is less than 3.5 seconds for clothes with smooth surfaces and less than 4 seconds for napped fabrics.

Flammability Testing Parameters   

These are the flammability parameters that should be considered during testing.

1. Fire Resistance 

It is the ability of a material to resist fire, heat, flame, ignition and burning.

2. Flame Spread 

Flame spread, also known as a rating of surface burning, defines how rapidly a flame can spread on tested cloth.

3. Reaction to Fire

It is characteristic of any material that how it reacts to fire. How does material ignite, burn, propagate to flame, and sustain combustion? It is also observed which types of smoke and gases are produced.

4. Flashpoint Testing 

Flashpoint testing is the method for determining the lowest temperature at which a material’s vapour ignites.

Worldwide Fabric Flammability Standards

Here is the list of flammability standards for textiles country-wise.

United States of America 

Europe                                                                    

China                                  

Japan   

Australia, Canada, and International           

Which Type of Textile Products Require Flammability Testing? 

Textile products need flammability testing for user safety. We can categorize two sectors where cloth resistance to fire is mostly monitored.

1. Apparel
2. Home textile

Apparel                               

This category involves all wearing garments. There is a special focus on children’s sleepwear and baby dresses, which must be flame retardant. The testing criteria for children’s clothing is very strict among all flammability testing.

Home Textiles       

Many products in this sector require flame resistance testing. This category includes upholstery, curtains, carpets, textiles used for tents, and transportation like buses, aeroplanes, and trains.

What are the Potential Benefits of Fabric Flammability Testing?  

Textile flammability testing helps in getting the following benefits.

• Consumer safety
• Product Development
• Meet the requirements of International Standards
• Following Regulatory compliance
• Reduces the Risk of Investment Losses

Conclusion  

Fabric Flammability testing is performed to determine the fabric’s burning behaviour under controlled and defined flame. It is done to ensure consumer safety against fire-related injuries. Three main methods, Vertical, Horizontal, and 45–degree flame tests, are used to perform testing. 

FAQs

What is meant by Fabric Flammability?

It means how easily a fabric can burn. This term is used to measure the fabric resistance to ignite, burn or propagate to flame.

Which standard for fabric flammability is widely used?

ASTM D1230 standard for fabric flammability is widely used. It is performed for all apparel items except children’s sleepwear and protective clothing

What are Textile Flammability Testing Methods?

These are the methods most commonly used for fabric flammability.

• Vertical flame test
• Horizontal flame test
• 45-degree angle flame test

What is the Federal Flammable Fabric ACT?

Federal law of Flammable Fabric ACT (FFA) ensures the safety of end users by implementing the regulations on flammable clothing.

How flammable is fabric?

The flammability of a fabric depends on the fabric type, weight, structure, and chemical finishes applied to it.

Which are the most flammable fabrics?

Cellulose fibres, raised surface fabrics, silk, nylon, Acrylic, and polyester are the most flammable fabrics.

Related Resources

Experience and Insights on 16 CFR 1610 Flammability Test in Textile

Flammability Tester