Glossary
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Abrasion resistance: mechanical test which together with other physical measurements such as tear strength and tenacity, can be used to give an indication of the estimated wear life of garments. Under normal conditions, the higher the abrasion resistance of the fabric the longer the average wear life of the garment. The most common test procedures are Martindale and disk abrasion where a representative swatch is subject to repeated circular rubbings by a mechanical abrader. The level of abrasion resistance is judged as being the point at which a hole begins to appear in the fabric. Although not part of the EN 531 and EN standards for personal protective equipment, EN 530 has been accepted as a European standard for measuring abrasion resistance.
Afterburn: the period during which a fabric burns after the flame has been removed or extinguished. European test method EN 532 standards for personal protective equipment.
Afterglow: the period during which a fabric glows after the flame has been removed or extinguished. European test method EN 532 is included in the EN 469 and EN 531 standards for personal protective equipment.
Antistatic: Du Pont’s new generation of meta-aramid fibres and fibre blends. The DuPont™ Nomex® Antistatic series were developed to meet the growing need for high performance, specially tailored products. See DuPont™ Nomex®.
Antistatic: the rubbing of a fabric, even in the course of normal everyday wear, can build up static electrical charges of over 5000 volts. Should the wearer then touch a grounded object the discharge promotes a small electric shock, accompanied by an electric spark. In the presence of flammable vapours or dust, the static electrical charge may be great enough to cause an explosion. To limit the build up of static and improve the comfort of garments, Du Pont have introduced a carbon core P140 fibre into a number of the DuPont™ Nomex® brand fibre blends. Unlike surface treatments, the antistatic properties of P 140 are a permanent feature of the garment. Retreatment is therefore unnecessary.
Aramids: family of polymers with certain common properties. The molecules contain aromatic benzene rings and amide groups. DuPont manufactures fibres from two types of aramid: DuPont™ Nomex® meta-aramid and DuPont™ Kevlar® high strength para-aramid. DuPont operates aramid plants in the United States, Japan, Great Britain and Spain.
Arc test: see Electric arc.
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Basic dye: coloration medium recommended for the dyeing of non-crystallised DuPont™ Nomex® brand fibres. See cationic dyes.
Benzyl alcohol: chemical used to dye and crystallise non-crystallised DuPont™ Nomex® brand fibres. See carrier.
Berkel Patent: issued to a Du Pont researcher whose team discovered that the mix of meta- and para -aramid fibres reduces fabric shrinkage enabling fabrics to remain intact when exposed to flame and heat. Often referred to as ’break-open-resistance’. With DuPont™ Nomex® III fibres this discovery was offered for the first time in a commercial product. Today the technology is also used in DuPont™ Nomex® Antistatic, DuPont™ Nomex® Comfort, DuPont™ Nomex® Outershell Tough fibre blends.
Blends: refers to the combination of different fibres in a spun yarn.
Break-open resistance: see non-break-open protection.
Burns: measures the degree of injury to human tissue caused by heat. Second degree burns: irreversible skin injury at depths of between 100 and 2000 microns. Third degree burns: irreversible damage to the skin at depths beyond 2000 microns. Pain is acknowledged as the level immediately preceding a second degree burn injury. Du Pont’s DuPont™ Thermo-Man® mannequin is used to predict the level and location of burns following exposure of the mannequin to a simulated flash fire.
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Carbonisation: a stage of decomposition as the result of exposure to heat. In DuPont™ Nomex® fibres carbonisation starts at around 370°C
Carrier: chemical which aids the dye to penetrate the dye sites during the coloration of DuPont™ Nomex® fibres. Is also the agent responsible for the crystallisation of DuPont™ Nomex® III fibres. See Benzyl Alcohol.
Cationic dyes: class of coloration medium recommended for the dyeing of non-crystallised DuPont™ Nomex® brand fibres. See basic dye.
Cellulosic: generic term referring to fibres composed from the constituents of plant cells. Both cotton and rayon are examples of cellulosic fibres.
CEN: acronym for "Comité Europeén des Normes", the organisation chartered by the European Union to develop European Standards (Euronorms).
Chemical resistance: DuPont™ Nomex® and DuPont™ Kevlar® polymers are highly resistant to acids, alkalis, oil and solvents. However, given the porosity of both woven and knitted textiles, Du Pont recommend that a non-flammable coating or impermeable membrane be incorporated into garments where a higher level of chemical protection is required alongside heat and flame protection.
Colour: several basic methods exist for introducing colour into a textile material, the most common being the injection of either a dye or pigment and printing. Yarns coloured during the fibre extrusion process are generally referred to as `producer coloured`. `Trade dyeing’ is a generic term describing a variety of techniques used by specialised spinners, weavers and dye houses to colour DuPont™ Nomex® brand fibre yarns and fabrics. The most common of these are stock fibre dyeing, yarn dyeing and piece dyeing (see stock dyed, yarn dyed and piece dyed). Such methods usually produce a lower level of lightfastness but facilitate the production of smaller batches of fabric in specialised colours.
Comfort: highly subjective and difficult to measure, comfort is, amongst other things, a function of garment design, fabric weight and handle, moisture absorbency and moisture removal , breathability , softness and texture. Changes to any one of these parameters may influence the perception of comfort. Du Pont have developed a range of fibres (see DuPont™ Nomex® Comfort) which are designed to optimise wearer comfort. Extensive comfort tests have been carried out at North Carolina State University (USA) and the Hohenstein Institute (Germany)
Continuous filament yarn: see filament yarn.
Convective heat: heat which is transmitted by convection from a central source as a flame.
Core spun: a staple spinning technique where two different fibre components are formed into a single yarn by making a core of one material and covering it with the other in one spinning operation.
Cotton: if treated with a flame retardant agent, garments made from 100% cotton may be used for heat and flame protective clothing. However, abrasion resistance is generally poor and total weight may be twice that of a DuPont™ Nomex® III garment with a comparable level of thermal insulation.
Cotton count: unit for measuring yarn. Common in the United States. Is based on a length of 840 yards (one hank), the count being equal to the number of hanks required to make up one pound. The higher the count (or number) the finer the yarn.
Cotton system: generic term for the textile system used to process short (bigger than 38mm) staple fibres into yarns and fabrics. Modified cotton spinning systems process fibres with a length of between 38 and 63mm.
Crystallinity and orientation: describes the alignment of molecules in a fibre. As a general rule, the higher the degree of crystallinity and orientation, the stronger the fibre. In a fully or higher crystallised and oriented fibre the molecules are packed tightly together with a strong degree of vertical alignment.
Crystallisation: the degree to which a polymer exists in a lattice structure.
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Decitex (dtex): unit for measuring yarn most commonly used in Europe. Indicates the weight of yarn in grams per 10,000 m. The lower the decitex, the finer the yarn. See Denier.
Denier: unit for measuring yarn, still used in many areas of the world and particularly in the United States. Indicates the weight of the yarn per 9000 m in grams. The lower the denier the finer the yarn. See Decitex.
Dry cleaning: garments made from DuPont™ Nomex® or DuPont™ Nomex® / DuPont™ Kevlar® fibre blends may be commercially laundered and dry cleaned. For specific information, please refer to the instructions of the garment manufacturer.
Durability: critical to the wearlife of a garment. Abrasion resistance and tear strength testing are methods for assessing durability.
Dye: a material soluble in water or a solvent used to colour textile materials. Du Pont recommend cationic or basic dyes for the coloration of DuPont™ Nomex® fibres.
Dolanit®: is a homopolymer acrylic staple fibre which is manufactured by Kelheim Fibres GmbH and distributed by Inspec Fibres GmbH for high temperature filtration applications.
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E89: Du Pont’s internal reference number for certain types of DuPont™ Nomex® used as heat barrier or backing for waterbarriers.
Ecru: textile terms meaning undyed or natural in colour
Electric arcs: an electric arc is the passage of current through ionised air. The occurrence of electric arcs may cause serious burns, either as a direct result of the blast or as the result of clothing igniting. The radiant energy generated by an electric arc is significantly higher than that generated by a typical flash fire. Electric arcs typical last less than one second and are explosive in nature. Apart from utility workers all electricians involved in the maintenance of industrial electrical equipment are at risk. Du Pont have conducted a significant amount of research into the characteristics of electric arcs and the type of protective clothing needed. Garments made from the DuPont™ Nomex® family of fibres offer a high degree of protection.
Euronorm (EN) or European Standard: A standard which carries with it the obligation to be implemented at national level and having priority over any conflicting national standard. Signatories include Community States and EFTA members. Prior to ratification Euronorms are generally known as PrENs (Preliminary European Norms).
EN 469: European standard for firefighters´personal protective equipment.
EN 659: European standard for firefighters´gloves.
EN ISO 11611 (ISO/DIS 11611: 2010); German version prEN ISO 11611:2011 Protective clothing for use in welding and allied processes
EN ISO 11612 Protective clothing - Clothing to protect against heat and flame (ISO 11612:2008): German version EN ISO 11612:2008
EN 533 Protective clothing - Protection against heat and flame - Limited flame spread materials and material assemblies
EN 1149/3 Protective clothing - Electrostatic properties - Part 3: Test method for measurement of charge decay
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Fabric construction: in a woven material, the type of weave including the number of warp and weft yarns per square centimetre of fabric. Described as ends and picks per 10 cm.
Fibril: the fragment resulting from the breaking of a fibre along its longitudinal axis (may be compared to the ´splintering´ of wood).
Filament yarn: most synthetic or manmade fibres are extruded from a solution or liquid polymer into single filaments, groups of which are then combined into multi-filament yarns. Filament yarns are less bulky and generally have higher physical properties than yarns spun from staple. Filament yarns of DuPont™ Nomex® are available, although their use in protective apparel is generally limited to a narrow range of race suits, flight jackets, clean room garments and liners.
Finish: generic term used to refer to impermanent treatments which aid either fibre processing or improve fabric performance. See Oleophobel.
Flame resistance: the extent to which a given material is able to resist combustion.
Flame Retardant: generic term referring to a chemical treatment designed to help material resist combustion. Flame retardants are applied topically and therefore may deteriorate during normal wash and wear cycles. Sometimes referred to as "FR Treatments".
Flammability: generic term used to refer to a materials ability to resist heat and flame.
Flash fire: refers to a sudden large scale flame or heat blast at extremely high temperatures caused by pressure changes and oxygen stimulation from an existing fire. DuPont™ Thermo-Man®, Du Pont’s instrumented mannequin is used to evaluate the performance of thermo-protective clothing under simulated flash fire conditions.
FR treatment: see Flame retardant.
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Greige: in textile terms meaning unfinished, undyed fabric.
Grin-through: term referring to the ´showing´ of the central fibre in a core spun yarn or the inner fabric though the open structure. May have a negative impact on both abrasion resistance and garment appearance.
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Heat transfer: measure of how quickly heat is transferred from layer to layer in a garment system as well as to the skin. The reduction, or at best, total reduction of heat transfer is critical to minimising burn injuries.
Heat Transfer Index: index used in EN standards to measure the transfer of radiant (EN366) heat through a given material. See also TPP.
Hybrids: generic term referring to fabrics composed of more than one type of yarn or fibre.
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IFR: abbreviation for "inherently flame resistant fibres", a term most commonly used in the USA. IFR fibres such as DuPont™ Nomex® and DuPont™ Kevlar® are able to resist combustion without the aid of chemical additives or treatments, i.e. they have permanent flame resistant properties.
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DuPont™ Kevlar®: Du Pont’s registered trademark for its high-strength para-aramid fibre. One of the most important manmade organic materials ever developed, DuPont™ Kevlar® brand fibre possesses a remarkable combination of properties that has led to its adoption in a variety of end uses since its commercial introduction in the early 1970´s. The overriding feature of DuPont™ Kevlar® fibres is its strength - more than five that of steel at equal weights. DuPont™ Kevlar® fibres also offer excellent thermal and dimensional stability, as well as low elongation to break. It does not corrode and resists attack by most chemicals. DuPont™ Kevlar® is also heat and flame resistant and enables fabrics made from DuPont™ Nomex® fibres to resist shrinkage and stay during high temperature exposures. Du Pont recommends the inclusion of DuPont™ Kevlar® fibres in allDuPont™ Nomex® fibre blends used for ´primary protective barriers´ such as turnout gear, coveralls and gloves.
Knitting: the formation of fabrics through the interlocking of loops of yarn or thread. Knitted fabrics are generally more ´open´ than woven or other non-woven textiles and therefore generally more flexible. DuPont™ Nomex® brand fibre ´knits´ are available for polo-shirts, jogging suits, hoods, knitted liners and underwear.
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Laundering: garments made from DuPont™ Nomex® and DuPont™ Nomex® / DuPont™ Kevlar® fibre blends may be commercially laundered or dry cleaned. For further information, please follow the instructions of the garment manufacturer.
Light fastness: measure of the extent to which the colour of any material changes after exposure to ultra violet light. In Europe, light fastness is generally measured on a 1 (poor) to (good) scale and in the United States on a 1 to 5 scale. ISO 105 B02 is generally used to measure lightfastness.
LOI: acronym for limiting oxygen index a measure of the percentage of oxygen needed in the atmosphere before a material will either ignite or burn. The LOI of DuPont™ Nomex® and DuPont™ Kevlar® fibres is approximately 29.
Limited Flame Spread: CEN test method for evaluating the flammability of the vertical flame test procedure.
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Man-made: fibres based on organic chemicals derived from natural oils. Includes cellulosics and synthetics.
Martindale: test method used to measure abrasion resistance via the circular rubbing of fabric against fabric.
Membrane (breathable): refers to a porous film which, through the careful regulation of the pore dimensions prevents the penetration of water and, at the same time allows perspiration vapour to be transmitted away from the body.
Meta-aramid: see aramid
Metric count: unit of yarn measurement. Indicates the number of kilometres of yarn per kilogram.
Modulus (or Young’s Modulus): the ratio of change in stress to change in strain within the elastic limits of a given material. High specific modulus is a key characteristic of DuPont™ Kevlar® brand fibres.
Moisture regain: water suspended in the atmosphere which may be absorbed by textile materials. At 4, 5 %, DuPont™ Nomex® fibres have a relatively low moisture absorbency rate.
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Natural fibres: such as cotton and wool. These fibre are not man-made.
Non-Woven: technical textile term used to refer to any fabric which is not woven or knitted, such as unidirectional fabrics and felts. See Sontara®.
DuPont™ Nomex®: Du Pont’s registered trademark for its high temperature resistant aramid fibre. Available in a variety of forms including continuous filament yarn, paper, honeycomb and staple. DuPont™ Nomex® fibres are used in a wide of applications such as electrical insulation, aircraft composites, hot gas filtration and protective apparel where high temperature and chemical resistance are critical.
DuPont™ Nomex® III: DuPont™ Nomex® III is Du Pont´s registered trademark for its patented blend of 95% DuPont™ Nomex® and 5% DuPont™ Kevlar® fibres. DuPont™ Kevlar® from the ´steel-like grid´which helps to keep fabrics intact during exposure to intense heat and flame. The DuPont™ Nomex® III fibre blend can be dyed by specialists commercial dye houses, weavers and spinners. After more than 25 years, DuPont™ Nomex® III is still the only fibre blend of its type commercially available on the marked. Due to its all round strengths, the DuPont™ Nomex® III fibre blend is used for a wide range of garments where thermal protection is required.
DuPont™ Nomex® Antistatic: an intimate blend of DuPont™ Nomex® (93%),DuPont™ Kevlar® (5%) fibres and P140 (2%), a carbon core polyamide sheath fibre with antistatic properties. Being engineered to offer a permanent solution to the problems of static build up in garments with no loss in thermo-protective performance or fabric handle. In the American and Asia Pacific regions its marketed as "DuPont™ Nomex®" III A.
DuPont™ Nomex® Comfort: blend of fine-fibre DuPont™ Nomex® (93%), DuPont™ Kevlar® (5%) fibres and P 140 (2%) antistatic component. The DuPont™ Nomex® Comfort fibre blend was developed in response to the need for high comfort garments with the same kind of thermo-protective performance as the DuPont™ Nomex® III fibre blend. The reduced fibre diameter and cross section of the DuPont™ Nomex® brand fibres further reduces fabric and surface roughness. Moisture wicking is also improved and the overall dissipation of metabolic heat generated by human physical activity increased. DuPont™ Nomex® Comfort fibre blend is available in a range of producer and trade dyed colours and is particularly suited to coveralls, underwear, hoods and a range of knitwear fabrics.
Nomex® Partner Program: Program initiated by Du Pont for industrial coveralls and fire-fighters turnout gear manufactured from one of the DuPont™ Nomex® family of fibres. The program sets a series of stringent requirements for heat and flame protection, wear life, aesthetics and design. Many of the requirements exceed those of EN 469 and EN 531. Garments approved under the program carry a distinctive Nomex® Partner Program Label. A comprehensive test report is available from the manufacturer for each approved garment style.
DuPont™ Nomex® Producer Coloured (PC): blends of DuPont™ Nomex® and DuPont™ Kevlar® fibres in which the component fibres are coloured by Du Pont. Yarns and fabrics manufactured from producer coloured fibres generally have a higher level of lightfastness than those which are trade dyed.
DuPont™ Nomex® Outershell Tough: an intimate blend of producer coloured DuPont™ Nomex® (75%) and DuPont™ Kevlar® (23%) fibres and P 140 (2%). The DuPont™ Nomex® Outershell Tough fibre blend was designed specifically in response to the firefighters need for higher performance garments at lower or equal weights, a concept easily translated to other end uses. The DuPont™ Nomex® Outershell Tough fibre blend is also top of the range in terms of lightfastness and abrasion resistance.
DuPont™ Nomex® /FR-Viscose: For applications where fabric softness and non-flammability are important, but garments are not intended to be worn as primary protective barriers, Du Pont have developed DuPont™ Nomex® / FR-Viscose blends. For coveralls and trousers, Du Pont recommends a 50/50 blend, a fabric weight of 250g/m² and a 2x1 twill weve. For shirts, Du Pont recommends a 65/35 blend and a plain weave 150g/m² fabric.
Non-break-open protection: one of the most effective ways to reduce second and third degree skin burns is to make sure that the barrier of protective clothing between the heat source and skin remains intact during exposure. At Du Pont this is called non-break-open protection or break-open resistance. Unlike conventional fibres, DuPont™ Nomex® consolidates and thickens when exposed to a high temperature heat source. The presence of DuPont™ Kevlar® in the fibre blend then prevents this swollen fabric from breaking open. Well engineered fabrics made from one of the DuPont™ Nomex® family of fibres which also contain DuPont™ Kevlar® maintain the all important protective barrier even during exposure to extremely high temperatures.
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Oleophobol: registered trademark for water and oil repellent treatments manufactured by Ciba-Geigy. Being based on the PTFE formulation of DuPont™ Teflon® water and oil repellent treatment.
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P 140: Du Pont fibre composed of a carbon core and polyamide sheath. P140 is used as the antistatic agent in a number of DuPont™ Nomex® fibre blends (generally 2% of the total). The relatively small quantity of polyamide does not affect flammability.
Package Dyeing: dyeing of yarns after the spinning or twisting process.
Pain: see burns
Para-aramid: see aramids
Partner Program: Program initiated by Du Pont for industrial coveralls and fire-fighters turnout gear manufactured from one of the DuPont™ Nomex® family of fibres. The program sets a series of stringent requirements for heat and flame protection, wear life, aesthetics and design. Many of the requirements exceed those of EN 469 and EN 531. Garments approved under the program carry a distinctive Nomex® Partner Program Label. A comprehensive test report is available from the manufacturer for each approved garment style.
Piece Dyeing: technical term used to refer to the trade dyeing of fabrics as opposed to the dyeing of staple or spun yarns. Piece dyeing generally produces the same light and washfastness results as other trade dyed DuPont™ Nomex® routes. A key advantage of the piece dyed route is increased flexibility, since woven fabrics may be prepared and stocked in ecru form.
Pigment: coloration medium. Differs from dye stuffs in that the particles are solid and insoluble. This is a key reason for the high level of lightfastness which pigments generate in man-made fibres.
Pigment injection: method of introducing a coloration medium during polymer preparation. Pigment injection gives the highest values in terms of light and washfastness.
Pilling: is caused by either the wearing or washing of a garment where fibres are broken away from the main body of the fabric (but still remain attached by stronger fibres), forming into a small ball.
Plain weave: one of the three basic types of weave (plain, satin and twill), plain weave is the simplest from of woven fabric the weft yarn passes successively over and under each warp yarn, alternating each row. Plain weavers have no right or wrong side.
Polyester: man-made fibre with a high level of strength, stability and abrasion resistance. FR polyester cotton blends are used for protective apparel although the relative degree of protection from flame and heat is low.
Polyester Cotton: see Polyester
PPE: acronym for Personal Protective Equipment. Often seen in the context of Euronorms.
Procon®: is a Polyphenylen sulfide (PPS) fibre developed by TOYOBO. It has excellent heat resistance, chemical resistance and also excellent resistance to hydrolysis. Procon® is a trademark of TOYOBO in Japan.
Producer coloured: term used to denote that a fibre has been coloured by the original producer. Generally speaking, producer coloured fibres give better wash and lightfastness results than trade dyed materials. Term covers both colour sealed and pigmented products. See also DuPont™ Nomex® producer coloured.
Pyjama check: type of weave whereby a strong reinforcing thread is introduced along the warp and weft at regular intervals. During thermal exposures, fabrics of this type are more stable, given that the check threads are of a higher density (and therefore of a higher strength).
proFlex4®: This is a modern welding protective suit made from patented fabric which has been developed by Aramex, Ibena and Du Pont. The special components guarantee among others that the norms as EN 470/1, EN 531, EN 533, EN 1149/3 are met.
- EN 470/1
Protective clothing for use in welding and allied processes - EN 531
Protective clothing for workers exposed to heat - EN 533
Protective clothing - Protection against heat and flame - Limited flame spread materials and material assemblies - EN 1149/3
Protective clothing - Electrostatic properties - Part 3: Test method for measurement of charge decay.
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Radiant heat: Heat which is transmitted by radiation from a central source such as a flame.
Rayon: flammable cellulose fibre. Not suitable without additional treatment for thermo-protective apparel.
Rental laundry: Generally companies who hire and take on responsibility for the maintenance of garments. An increasing numbers of rental laundries now include garments made from the DuPont™ Nomex® family of fibres in their offering.
Rib-Stop: weaving technique where reinforcing threads of a higher strength than those in those in the base fabric are introduced at regular intervals along the warp and weft. DuPont™ Nomex® Outershell Tough H Rip-Stop is the name given to a fabric in which reinforcing coloured aramid threads are introduced at regular intervals in a DuPont™ Nomex® Outershell Tough fibre blends. The Rip-Stop technique further reduces fabric shrinkage during higher temperature exposures and therefore increases levels of protection. Tear strength is also higher than standard fabrics made from the DuPont™ Nomex® Outershell Tough fibre blend. See Pyjama check.
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Satin weave: one of the 3 basic weaves (plain, satin and twill) in which the weft yarn floats over a number of warp yarns. Satin weaves generally have a smooth and lustrous surface.
Second degree burn: see Burns.
Sewing threads: often neglected but still a critical part of garment manufacture. Sewing threads having a lower decomposition temperature than the fabric may reduce the level of protection offered by the garment. Sewing threads of DuPont™ Nomex® and DuPont™ Kevlar® brand fibres are readily available.
Shrinkage: see Thermal shrinkage and Wash shrinkage.
Singeing: in textile terms the process of burning off surface fibre ends from a yarn or fabric surface, helping to promote a smoother, cleaner finish. Singeing also helps to reduce pilling.
Source lists: available from Du Pont. Indicate where yarns, fabrics, accessories and garments made from the DuPont™ Nomex® family of fibres can be purchased. Regularly updated by Du Pont as a service to end users as well as to industry.
Spun yarns: refers to yarns which have been drawn and twisted from staple into the finished product.
Staple: or staple fibres. Short and with man-made products, generally regular lengths of fibre which are opened, carded, drawn and twisted into a spun yarn for in woven or knitted materials.
Steel fibre: can be included as a component of 1% and more during the manufacturing of the yarns in order to obtain antistatic properties on woven and knitted fabrics.
Stock dyeing: dyeing of fibres by spinner before spinning yarn.
Stretch break: process of stretching a bundle of continuous filament yarns or tow under tension until the point at which they break. Stretch broken fibres are used like staple fibres to spin yarns. The stretch break process is generally able to produce finer and stronger yarns than the conventional staple/ cotton or woollen spun route.
Surface treatment: treatment to the surface of either a fibre or fabric to improve the performance of the material. Treatments may be used amongst other things as a moisture repellent or antistatic agent, to promote flame resistance or simply to improve fabric aesthetics and comfort. Because of their impermanent nature Du Pont does not generally recommend the use of surface treatments. See also Finish.
Synthetic: generic term used to refer to the range of man-made fibres which are produced from polymers.
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Tear strength: the ability of a cut fabric to resist tearing or ripping.
Tenacity: refers to the strength of a fibre, yarn or fabric.
Tex: for measuring yarn. Indicates the weight of yarn in grams per kilometre.
Textile properties: general term used to refer to a wide range of characteristics in a fabric including abrasion resistance and overall handle or feel.
Thermal insulation: the rate at which a given material is able to prevent the transmission of cold or heat penetration. TPP is one way of measuring thermal insulation. EN 366 and EN 367 measure the insulation of protective clothing against heat. Also required for En 469 and EN
Thermal shrinkage: the effect of dimensional change in a fabric after exposure to convective and/or radiant heat. In DuPont™ Nomex® fibre blends containing DuPont™ Kevlar®, the high-strength high temperature resistant fibre forms steel like grid which by helping to reduce the rate of thermal shrinkage, contributes to an increased level of personal protection. See Non-break-open protection.
DuPont™ Thermo-Man®: Du Pont’s burn test mannequin used to evaluate the performance of protective garments under simulated flash- fire conditions. In the tests the mannequin is dressed in the garment under evaluation and exposed to intense radiant and convective heat of approximately 2 cal / cm²/sec. for a period of up to 10 seconds, the 122 sensors systematically recording the rise in temperature of the mannequin’s glass-epoxy skin. A sophisticated computer programme then calculates, predicts and displays graphically the resulting area body, grading them as to their severity in 2nd and3rd degree injury. Developed around 20 years ago in conjunction with the United States Air Force, DuPont™ Thermo-Man® is used extensively to evaluate the thermo-protective performance of garments, often in co-operation with manufactures and end users.
Third degree burns: see burns.
Topical treatments: refers to the treatment of the surface of a fibre or fabric. See also Surface treatments.
TPP: acronym for Thermal Protective Performance - a test method developed by Du Pont to measure the thermal insulation of a fabrics to a 50/50 mixture of convective and radiant heat for varying amounts of time. A calorimeter then records the rate of heat transfer, translating this into an approximate burn rating. The Du Pont developed method is the basis for ISO heat transfer evaluations. A version of the TPP test has also been adopted by CEN for the evaluation of heat and flame resistant clothing (EN 366 and 367).
Toxic fumes: refers to gases emitted from a material after exposure to heat.
Trade dyed: generic term referring to fibres or fabrics which are not producer coloured, I. e. coloured by the original fibre producer. Trade dyed products generally have a lower level of light and washfastness than producer coloured items. Key advantages of the trade dyed route are the range of colours available and flexibility in delivery. The three principal routes for the trade dyeing of DuPont™ Nomex® fibre products are stock dyeing, fibre dyeing and piece dyeing. See Stock dyed, Trade dyed.
Twaron®: "is a lightweight, super strong synthetic fiber made from aramid polymer. Aramid molecules are characterized by relatively rigid polymer chains, linked by strong hydrogen bonds, which transfer mechanical stress back and forth, rather like a zipper. This permits the use of chains of relatively low molecular weight. Twaron’s unique characteristics derive from the ability of the aramid molecules to orient themselves along the line of flow during the spinning process producing the fiber, forming straight strands that resemble uncooked spaghetti. By comparison, the much weaker fibers made from polymers such as nylon and polyester resemble the tangled mass that cooked spaghetti becomes." (source: homepage of Twaron®)
Twill weave: one of the three basic weavers (plain, satin and twill) in which the weft yarn floats across two or more warp yarns. Twill weaves are characterised by diagonal (either right handed or left handed) pattern on the face of the fabric.
Twist: in textile terms the spiral arrangement of fibre around the axis of the yarn. The number of twists is referred to as turns per centimetre.
Type: e.g. Type 450, Type 455 (also referred to as T 450, T 455 etc.) - internal reference numbers for DuPont™ Nomex® family of fibres. Type 450 refers to 100% DuPont™ Nomex® meta-aramid staple, Type 455 to theDuPont™ Nomex® III fibre blend.
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Uncrystallised: see Crystallinity. Secondly that the fibres or fabrics have a high rate of heat absorption, are sweat wicking and quick drying. Du Pont have developed a range of high comfort fine fibre DuPont™ Nomex®.
Underwear: of primary importance is that the materials used have a high melt point. DuPont™ Nomex® Comfort blends for use in underwear.
UV stability: the rate at which a material’s properties remain stable after exposure to ultra-violet (day) light. The protective features of the DuPont™ Nomex® range of fibre products remain unchanged after periods of extensive exposure. As with all coloured products the one area of exception is lightfastness
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Velcro: hook and loop as fastener which may be produced in a way which is suitable for thermo-protective clothing. The tape should be a fabric made DuPont™ Nomex® fibres, the hooks and loops from a heavy duty nylon. Garments made from one of theDuPont™ Nomex® family of fibres which use Velcro tape should be designed to ensure that the tape is adequately covered to prevent the nylon components from igniting.
Vertical flame: test procedure used to evaluate the flammability or non- flammability of a material. In the test a strip of fabric is exposed to a vertical flame for a pre-specified period. After the flame is extinguished the number of seconds of after burn or afterglow is measured and an assessment of flammability made. The test is also used to measure the extent to which a fabric chars (char length) after exposure to the flame. See also limited flame spread.
Viscose: cellulosic fibre which in its untreated state is highly flammable. May however be chemically treated or preferably its structure chemically modified to increase its resistance to flame. A generally fine and porous fibre, viscose produces soft fabrics with a high level of moisture absorption.
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Warp: the vertical yarns in a fabric, running parallel to the selvage edge.
Washfastness: the stability of a fabric after washing under recommended conditions, DuPont™ Kevlar® including dimensional and colour stability. The washfastness of DuPont™ Nomex® or DuPont™ Nomex® based fabrics is excellent, contributing to the exceptional wear life of garments made from one of the DuPont™ Nomex® family of fibres.
Wash shrinkage: the rate of dimensional change in a fabric after washing.
Water repellence: the ability of a material to resist penetration by water. Woven and knitted textile materials are not generally water repellent. Non flammable treatments, coatings and membranes are therefore recommended to help prevent the ingress of water.
Wearlife: the period a garment can be worn before it no longer serves its original purpose. Wearlife is dependent on a number of factors including lightfastness, washfastness, and fabric shrinkage and abrasion resistance. Wearlife is directly related to the average cost of a garment and is therefore a critical part of any purchasing decision. The wearlife of garments made from the Nomex® family of fibres is exceptionally high. Examples of more than 10 years service with garments being washed more than 500 times is not unusual.
Weaving: process of forming thread into fabric by running horizontal weft yarns over and under a series of vertical warp yarns. The style of weaving can effect both fabric performance as well appearance.
Weft: the horizontal threads inserted over and under the vertical warp yarns to form a woven fabric.
Wicking: the ability of a textile material to move or transfer moisture or liquid from one place to another.
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Yarn dyed: refers to the trade dying process of introducing the colour into a spun yarn.
DuPont™, Nomex®, Kevlar®, Tyvek®, Teflon®, Thermo-Man® and Arc-Man® are registered trademarks or trademarks of E. I. du Pont de Nemours and Company or its affiliates.
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