Flame retardant fabric
A sailor wearing a fire-retardant suit checks for hot spots during a crash and smash drill
Fire-retardant fabrics are textiles that are more resistant to fire than others through chemical treatment of flame-retardant or manufactured fireproof fibers.
Properties
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The term fire-retardant as applied to organic (i.e., containing carbon) materials, is intended to refer to reduced fire hazard, as all will burn under certain circumstances. The tests used specified in building codes, such as NFPA 701, are more correctly flame resistance tests, which test a fabric's ability to resist ignition with the flame size and duration in the test conditions.[1] The result is a comparative test, which provides a measure of the material's resistance to propagating combustion caused by small scale ignition sources. These tests do not predict the burning characteristics of full scale hazards. In many cases, if exposed to a sufficiently large and sustained exposure fire, the fire-retardant fabrics will burn vigorously. Polyester is inherently flame retardant, and therefore doesn't flare up when applied to various tests. Any amount of heat delivered within a long enough time interval will have no impact on the fabrics' integrity while a limited amount of heat delivered within short enough time interval may ignite or melt the fabric.
Curtains
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Inherently flame-retardant fabrics are certified in the United Kingdom by various British Standards. Fire-retardant fabrics sold in the UK for use as curtains must abide by BS 5867 Part 2 B & C, a British Standard. Other relevant UK standards include BS 5815-1 2005, BS 7175, Crib 5, IMO A563 and NFPA 701.
Stage drapery
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Fabric flammability is an important textile issue, especially for stage drapery that will be used in a public space such as a school, theatre or special event venue. In the United States, Federal regulations require that drapery fabrics used in such spaces be certified as flame or fire-retardant. For draperies and other fabrics used in public places, this is known as the NFPA 701 Test, which follows standards developed by the National Fire Protection Association (NFPA). Although all fabrics will burn, some are naturally more resistant to fire than others. Those that are more flammable can have their fire resistance drastically improved by treatment with fire-retardant chemicals.
Inherently flame-retardant fabrics such as certain brand polyesters are commonly used for flame retardant curtain fabrics.
Fire-retardancy fabric treatment
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Fire-retardant fabrics are normally treated to different British Standards; normally this depends on the end usage of the fabrics. BS 476 is a fire treatment for fabrics that are normally for wall hanging, and must only be used as for that purpose, where as CRIB 5 is a fabric fire treatment for upholstery and must only be used for furnishing and upholstery purposes, even if both fabrics have been treated for fire-retardancy.
The relevant standards for fire-retardant fabrics include:
- BS 5852:2006 describes the best practice methods to assess the ignitability of single material combinations, such as covers and fillings used in upholstered seating, or complete items of seating. These tests determine the effects of a smouldering cigarette, or other flaming ignition sources such as burning matches or a four-sheet full-size newspaper. This standard can be used to establish the potential ignitability of components in conjunction with other specified materials.[2] BS 5852:2006 first looks at the criteria of ignition, and the health and safety of operators. It then explains the various apparatus, before focussing on smouldering ignition sources – such as a cigarette, butane gas flames and flaming wooden cribs. It also looks at ways to test for the ignitability of upholstery composites and complete items of furniture. The standard concludes with a final examination and test report. BS 5852:2006 replaces the older certification standard, BS 5852 - 1990.[3]
- BS 5867 is for flame retardant fabrics. It relates to curtains, blinds and drapes for windows when tested by the methods specified in BS 5438:1976. Where appropriate, a cleansing or wetting procedure specified in BS 5651 may also be required.[4]
- Source 5 (Crib 5) is related to upholstery and furniture coverings, and is related to BS 5852.[5] The "crib 5 test" uses a small structure (or "crib") made from wooden sticks that are glued together. A lint pad is attached at the bottom and propane-diol is added when it is to be used in to test upholstery. In a test, the "crib" is ignited with a match. To decide whether the test has been passed or not the fabric cover/filling upholstery arrangement is assessed to see whether there is flaming or smoldering on both the outer cover and the interior filling material. Assuming it does not ignite or smolder, the upholstery arrangement will pass the test as "non-ignition". Similar tests include "Source 0" (smouldering cigarette) and "Source 1" (simulated match)tests.
- Class 0
- Class 1
- BS 476
The M1 standard is a European standard that is widely used in Europe only. Most UK fire officers are reluctant to accept MI certification, they prefer BS certificates.
Durability and cleaning of fabric and drapes
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Flame retardant curtains
When a fabric is designated as inherently fire-retardant, permanently fire-retardant, or durably fire-retardant, the flame retardancy will last for the life of the fabric as it has been woven into the fabric fiber itself. The drapery can be laundered or dry-cleaned as recommended by the drapery manufacturer. In the case of fabrics that are designated as fire-retardant, that have been topically treated with chemicals, the flame retardancy of the fabric will dissipate over time, particularly with repeated cleaning. As these chemicals are soluble in liquids-either water or dry cleaning fluid, these fabrics must be dry-cleaned with a non-liquid cleaning agent.[citation needed] The flame retardants work by coating the flammable fabrics with a mineral based barrier, preventing fire from reaching the fibres.
Typically, the flame retardancy of topically treated fabric is certified for one year,[citation needed] though the actual length of time in which the treatment remains effective will vary based on the number of times the drapery is dry-cleaned and the environmental conditions in the location in which the drapery is used. It is recommended that topically treated drapery be re-tested for fire-retardancy on an annual basis and re-treated by a qualified professional as needed.[citation needed]
See also
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References
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If you’re familiar with flame resistant clothing (FR), you’ve probably heard of terms such as treated fabrics and fibers or inherent fabrics and fibers. However, there are some key differences when talking about flame resistant fibers and fabrics. Failure to understand those differences could result in lapses in safety. It’s important to know how these fit in particular environments.
In this post, we’ll touch on the history of flame resistant fibers and fabrics. We'll define the terms mentioned above. We'll talk about some of the applications that they’re found in, and address how to clean and care for each type.
Some of this article might get a little technical...even a bit boring. But we want to break down some of the basics, no matter how dull they may seem. It's important to understand the various parts that make up flame resistant clothing.
It's also important to remember that garment care is critical with FR garments. Proper care guarantees that FR properties aren’t compromised. The goal will be to give you more information on the above so you can be safer in the workplace.
The history of flame resistant fibers and fabrics
It's widely agreed upon that flame resistant textiles were discovered in 1821. French chemist Joseph Louis Gay-Lussac first discovered that ammonium phosphates and borax were responsible for making textiles resistant to open flames. This discovery launched the flame resistant clothing industry we appreciate today.
Even as early as the mid 1600s, people in Paris were considering ways to reduce fire in theaters. At the time, they developed fireproof plaster and clay for buildings. This work encouraged others in the scientific community to work toward applying the same technology to clothing.
People viewed the development of flame resistant materials like we do today. They're used to prevent potential harm.
Fast forward to the 20th century, when scientists discovered that incorporating stannic oxide into fabrics made them resistant to flames. Stannic oxide is a powdery, off-white, product that's produced from high-grade tin metal. In time, these techniques added flame resistance to natural fibers.
This is just a brief overview of the origins of flame resistant fibers and fabrics. For more in-depth coverage, check out this article. The author does a great job walking through the history of flame resistant clothing.
Flame Resistant Fabric: What is Treated Fabric?
Fabric is a combination of fibers that, when put with other pieces of fabric, make a garment. We think of fabric as the manufacturing stage between fiber and garment. Treated fabrics are those that have a flame retardant chemical applied to make them flame resistant. The fibers used in these fabrics aren’t usually thought of as protective. They become flame resistant because of the chemical treatment.
The fibers used in these fabrics are usually 100% cotton fibers or are some combination of cotton and nylon. Regarding durability, the fabric made up of cotton fibers provides little resistance to abrasion. The fabrics with the nylon fiber added to them perform much better with resistance to abrasion. Treated fabrics work well in utility, oil and gas, chemical, and petrochemical applications.
Care for treated fabrics should take place in water with a hardness of 1.5 grains (25ppm) or less. Less hardness is ideal as hard water contains mineral salts that can leave deposits on the fabric. These deposits could negate the flame resistant properties of the garment. Deposits could even serve as fuel if the garment comes in contact with an ignition source.
Flame Resistant Fibers: What are Treated Fibers?
Treated fibers are those that have a flame retardant chemical that’s applied during the fiber forming process. As a result, it makes the fibers, flame resistant fibers. Fabrics made from treated fibers are flame resistant for the life of the garment. The flame retardant chemical can’t be removed by normal wear or laundering. The garment would no longer be flame resistant only if it becomes torn or soiled to the degree that the soil won’t wash out.
One fiber type is a treated 100% rayon. Lenzing FR® is a synthetic cellulosic fiber made by Lenzing AG. These fibers get treated in the fiber forming process and are flame resistant forever.
Another fiber type would be a blend of cotton and Modacrylic fibers. Fabrics made of these fiber blends are characterized to have a soft and comfortable cotton-like hand. The Modacrylic fiber that gets added has soft and strong components. It’s also resistant to chemicals and solvents. This resistance makes these fiber types ideal in flame resistant environments.
Applications for these fiber types are a bit more general. Industrial protective clothing, utilities and fire fighter work uniforms are good matches. Like treated fabrics, it’s recommended that treated fibers get washed the same way. Water that is too hard could leave deposits that could ignite if exposed to an ignition source.
The only significant difference between caring for the two types is that the Modacrylic /cotton blends should be treated in soft water. Use a non-chlorine bleach as well so you don't weaken the fabric.
What are Inherent Fabrics and Fibers?
You don't need to treat inherent fabrics and fibers with chemicals. The FR properties are an essential characteristic of the fiber chemistry. Once again these fibers are FR fibers, but from the point of manufacturing of the fibers. Both inherent fabrics and fibers cannot lose their flame resistant properties from normal wear or laundering. The garment will keep its flame resistant characteristics throughout its life.
Modacrylic fibers are the most popular inherent fibers. They are most often found in blends with other inherent flame resistant fibers. The modacrylic fibers are often combined with various percentages of lyocell, para-aramid or polyamide imide fibers. These combinations make a durable fabric that meets NFPA 70E CAT2 and NFPA 2112 standards. Another popular inherent fiber is NOMEX. In clothing applications, NOMEX comes as a stand alone fiber or often in a blend with KEVLAR.
Inherent fabrics and fibers are found in petrochemical, electrical and utility industries. Another popular application is firefighter station wear and turn out gear. Most inherent fabrics and fibers are not recommended for use in welding operations or around molten substances. Caring for inherent fabrics and fibers is the same as the treated types. Soft water is recommended as hard water contains mineral salts that can leave insoluble deposits on the fabric. These deposits could negate the flame resistant properties of the garment. Chlorine bleach is also not recommended as it will weaken the fabric.
Bulwark provides much of this information as a leader in the flame resistant garment industry. This is also not necessarily an endorsement of Bulwark. There are other brands that manufacture high-quality flame resistant garments as well. The most important thing to understand is what fabrics and fibers build the garments that keep you safe while on the job. If you would like to schedule a demo of our private uniform store software, click the link below. We can make it easier for you to put your team in the proper safety apparel.
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