Fire retardant textiles

Fire retardant textiles

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  Fire Retardant Textiles Submittedto:- Dr. Apurba Das Submitted by:- Subham -2017TTE2058 Gaurav Nagar -2017TTE2044 Himanshu Singh - 2017TTE2049 Shashi Sony - 2017TTE2052
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  Fire Retardant Textiles Althoughall Textiles 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 called flame Retardant Textiles. Introduction
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  History Asbestos was oncea miracle substance. An abundant rock, it breaks into fibers that mix easily with plaster, fabrics, tiles, and construction materials, making them all extraordinarily fire resistant. But those fibers don't stop there. When tiles break or insulation crumbles, boilers shatter or dust accumulates, those asbestos fibers crawl their way into people's lungs, where they cause cancer and other diseases.
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  Importance of FireRetardant Textiles • Recent studies have revealed that in 24% of fire accidents, the first item to catch fire is textiles • 28% casualties were due to burns • 48% due to smoke/gas • 13% due to combined effects of burns, gas and smoke • 11% due to other causes • These emphasize the role of textiles in limiting the spread of fire and casualties due to it.
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  Fabric flammability isan important issue, especially for stage drapery that will be used in a public space such as a school, theatre or special event venue. Use of reduced flammability materials, testing of both materials and complete products, regulations and legislation have been applied to the problem. Contd..
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  Factors Influencing TheFlame Retardancy • The thermal or burning behavior of textile fibers • The influence of fabric structure and garment shape on the burning behavior • Selection of non-toxic, smoke-free flame-retardant additives or finishes • Design of the protective garment, depending on its usage, with comfort properties • The intensity of the ignition source • The oxygen supply.
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  Flame retardancy is commonlymeasured by the LOI the amount of oxygen needed in the atmosphere to support combustion. Fibers / fabrics with a LOI >25 are said to be flame retardant, meaning there must be at least 25% oxygen present for the fabric to burn. The higher the LOI the more fire retardant the fabric is.
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  Functions of fireretardant textiles •Maintain a barrier to isolate the wearer from the thermal exposure •Traps air between the wearer and the barrier to provide insulation from the exposure •Reduce burn injury •Provide escape time •Does not burn, melt or drip
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  Requirements in FRProduct: • Fire and heat protection. (Also, if necessary, other Protection properties: High visibility, antacids, antistatic...) • Comfort, aesthetics, durability. (Breathability, strength, abrasion, stable colour fastness, easy care, weather resistance.) • Price. (The cost must be reasonable and according to the different risk situations. The best solutions at the best price)
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  Flame retardant fabriccan be achieved by some methods • FR by chemical treatment • FR by heat resistant fibers • FR by suitable Structural Engineering
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  FR by chemicaltreatment What is FR chemical treatment ? Flame retardant is define as a compound used in cloth and plastic material to raise the ignition point of the material, thus making it resistant to fire. So for improving the FR properties of clothes with help of chemical is chemically treated FR fabric.
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  Classification of FRchemical treatment On the basis of durability of the flame retardant finish- • Non-durable treatment • Semi-durable treatment • Durable treatment On the basis of functional group- • Nitrogen containing flame retardants • Halogen containing flame retardants • Phosphorous-based flame retardants • Inorganic compounds based flame retardants
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  Nitrogen Containing FRMechanism • Nitrogen gas is released into the atmosphere • Inert gas lowers the concentration of flammable vapors • Melamine transforms into cross-linked structures which promotes char formation uses: Foams, Nylons and Polymers.
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  Halogenated FRs • theyAct in the Vapor phase • Reduce the heat generated by flames, thereby inhibiting the formation of flammable gases • Behave according to a “Free Radical Trap” theory which is depicted as follows:
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  Phosphorus Containing FRs •Acts in solid phase • Additive to material it’s protecting • Reacts to form phosphoric acid • Acid coats to form “char” • Char slows down pyrolysis step of combustion cycle. triaryl phosphate Ammonium polyphosphate phosphate
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  Inorganic FRs • Undergodecomposition reactions • Release of water or non-flammable gases which dilute the gases feeding flames • Adsorption of heat energy cools the fire • Promote production of non-flammable, resistant layer on the material’s surface • Uses: PVC, Wires and Propylene
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  FR by flameresistant fibres • Textile products can be made FR by using fibers that are inherently Fire resistant (e.g, polyoxazole, polymides, carbon, asbestos, glass, kyrol, sulfur and aramides) • Or by using manufactured fibers that have FR chemicals included in the solution or melt before they are spun through spinneret rendering a Fire retardant chemical structure. Examples : FR polyester, FR polyamide, FR wool.
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  FR by SuitableStructural Engineering • A Twill/satin woven fabric tends to reflect light if used in outer surface. • A flat yarn/fibre will reflect more heat due to more surface area. • A suitably treated porous fabric [eg. non-woven] will tend to resist propagation of heat from outer atmosphere to the wearers body. • A hollow fibre and hollow yarn with low packing fraction will insulate the body from influence of outer heat .
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  Fire protective clothing:3 layer arrangement (from bottom to top: outer shell, moisture barrier, and thermal liner)
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  LAYERED STRUCTURE For thepurpose of protection and comfort Flame resistant outer shell and Thermal liner composed of a moisture barrier Thermal barrier and a lining material
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  Outer Shell Purpose:- • Toresist direct flame without burning or degradation • To reflect radiant heat • To resist cut, tears and abrasion • Flame-retardant fibres, such as aromatic polyamides (aramids) and polybenzimidazole (PBI) are used • The outer shell utilizes aluminized surface to reflect radiant heat
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  Moisture Barrier Purpose:- • Toprovide protection against water as well as against many common liquids such as chemicals and blood-borne pathogens. • The moisture barrier can be a micro porous or hydrophilic membrane or coated textiles • Micro porous poly tetra fluoro ethylene, hydrophilic polyurethane laminates or coated fabrics or hydrophilic polyester laminates used.
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  Thermal liner Purpose:- • Toprevent the transfer of heat from the environment to the body. • It can consists of a spun laced, nonwoven felt or laminated to a woven lining fabric • At the same time it should allow the escape of moisture due to perspiration.
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  Air Gap • Theair gap between the skin and the garment is an important parameter to estimate the amount of heat that would be transferred to the skin and hence cause burns • It has been found that convection and radiation heat transfer modes occur within the air gaps for gap widths that are bigger than 6.4mm • While energy transfers by conduction and radiation modes for smaller gaps
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  Ultralight, highly thermallyinsulating and fire resistant aerogel by encapsulating fibers Aerogel is a synthetic porous ultralight material derived from a gel, in which the liquid component of the gel has been replaced with a gas.The result is a solid with extremely low density and low thermal conductivity.
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  Aerogels are goodthermal insulators because they almost nullify two of the three methods of heat transfer – conduction (they are mostly composed of insulating gas) and convection (the microstructure prevents net gas movement). They are good conductive insulators because they are composed almost entirely of gases, which are very poor heat conductors. (Silica aerogel is an especially good insulator because silica is also a poor conductor of heat; a metallic or carbon aerogel
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  Evaluation Parameters forFR Textiles •Ease of Ignition •After Glow Time •Extent of After Glow •Char Length •Flame Spread Time, Debris or Drips •Smoldering Time •Limiting Oxygen Index •Heat Transmission Factor •Heat Transfer Index •Molten Metal Splash Index •Smoke Opacity •Toxicity
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  Performance Testing • Thermalprotective performance (TPP) rating • TPP rating - a reliable method to predict protective performance of clothing. • Thermal protective performance (TPP) rating - the time required for total heat energy to cause a second-degree burn on the reverse side of the fabric multiplied by the intensity level of the heat exposure gives the TTP rating of the fabric.
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  Convective Heat TestMethod • Standard - ASTM D4108-82 • Gas flame - Methane gas • Heat flux - 84 ± 2 kW/m2 (2.00 ± 0.05 cal/ cm2/second) • Distance between fabric sample and the burner top – 50 mm • Air gap between fabric and copper sensor – 3.2 mm
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  Performance Testing • Convectiveheat test method • According to ISO 9151, incident heat flux can be calculated based on the temperature rise data of the sensor as follows where m = mass of the copper disk (0.018 kg) Cp = specific heat of the copper (385.0 J/Kg K) R = the rate of temperature rise of the copper disk in the linear region (oC/s) T = temperature (oC) t = time (s) A = the area of the circular copper disc (m2)
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  Convective Heat TestMethod • The tolerance time can be calculated from the temperature rise and the stoll’s criteria • TPP rating (cal/cm2) = Tolerance time (s) x Incident heat flux (cal/cm2.s) • Higher TPP rating of a fabric sample represents its better protective performance against flame exposures.
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  Radiative Heat TestMethod • Heat source - bank of nine electrically heated quartz tubes controlled by power stats • Exposure time – 0.2 s • Exposed area – 100 cm2 • Air gap between fabric and copper sensor – 6.3 mm
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  Factors Affecting TPPRating of Fabric • Effect of exposure conditions – Convective or Radiative Heat transfer through fabrics is generally higher when the incident heat flux is radiative only, rather than a mixture of radiative heat flux and convective heat flux • Effect of Fabric properties • Effect of fabric thickness • Effect of bulk density • Effect of weight • Moisture effects • Effect of air permeability • Effect of fabric construction
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  Advantages • Safe humanBody from fire. • Ensure safety in fire friendly working area. • Reduce the amount of losses.
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  Disadvantages • Less Comfortthan other cotton made fabrics. • More cost than cotton made fabrics • Need extra care to maintain for long term use • Not as much fashionable as other fabrics have. • Very high add on (6-10%) (makes fabric heavy) • Stiffening of material • Brittleness and hand loss
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  • Back coatingsfor institutional Drapery, Upholstery, Carpets • Aircraft /Automotive textiles • Mattresses and bedding • Racing suits • Fire Fighters suits • Children’s nightwear • The military Application field
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  Some Market Statistics Worldannual Protective textile consumption
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  What Lies Ahead?? •Comfort & aesthetics Breathability, strength, abrasion, stable colour fastness, easy care, weather resistance. • Smart clothing Response to various physical, chemical environmental stimulii • Environment friendly Use of Natural and biodegradable fibres with an energy efficient and less water requiring manufacturing process.
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  New Reasearches Researchers atthe Polytechnic University in Turin, Italy, have discovered a safer fireproofing method. Whey, a byproduct of cheese production, contains casein, which in turn contains a lot of phosphate groups. Phosphate groups are important because when they catch fire, they quickly turn to char and so give only a dead end for a flame to follow.
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  FABRIC FLAME TESTS Flame-resistancefabrics. From left to right: casein- treated cotton, casein- treated polyester, casein- treated cotton-polyester blend.
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  Inferences  Flames onthe casein-coated cotton self-extinguished after only consuming 14 percent of the fabric.  Only 23 percent of the polyester sample coated in casein burnt before the fire ran out of fuel.  The casein was unable to stop the fire burning up a cotton-polyester blend, but it did slow it down, with the fire taking 60 percent more time to consume the treated blend then it did an untreated blend.
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  Marlan  Marlan® isa permanent flame resistant fabric, designed to protect from molten metal splashesin foundries sector. Marlan® meets with the highest values of European and American Standards norms, related with molten metal hazards.  According to the European Standard EN ISO 9185, this fabric has the maximum value D3 for protection against molten aluminum splashes and E3 for molten steel/iron splashes  Marlan's protective properties are inherent, what means that the protection level doesn't decrease with the fabric use, or after washing.
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  CONCLUSION  Fire prooffabrics are arranged in the form of several layers, where each plays its own function of thermal insulation, thermal barrier and moisture barriers.  Weight, thickness and structure of the fabric play an important role in influencing the Moisture Vapor resistance Value and Radiant Protection.  The air gap between the skin and fabric play a very important role in determining the amount of energy transferred to the skin, which is described using various quantitative models built on different parameters. The heat transfer takes place through conduction, convection and radiation (greatest) depending on the air gap distance.
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  Thank You