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Abraded yarn: A filament yarn in which filaments have been cut or broken to create hairiness (fibrillation) to simulate the surface character of spun yarns. Abraded yarns are usually plied or twisted with other yarns before use.
Abrasion Mark: An area where a fabric has been damaged by friction.
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.
Acidic: A term describing a material having a pH of less than 7.0 in water.
Acid resistance: The property of withstanding contact or treatment with any acids normally encountered in use. The type of acid should be stated (i.e., organic or inorganic).
Adhesion: The force that holds different materials together at their interface and resists separation into two layers.
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: 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 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. Du Pont manufactures fibres from two types of aramid: NOMEX® meta-aramid and KEVLAR® high strength para -aramid. Du Pont operates aramid. Du Pont operates aramid plants in the United States, Japan, Great Britain and Spain.
Arc test: see Electric arc.
Balloon: The curved paths of running yarns about the take-up package during spinning, downtwisting, plying, or winding, or while they are being withdrawn over-end from packages under appropriate yarnwinding conditions.
Basic dye: coloration medium recommended for the dyeing of uncrystallised fibres. See Cationic dyes.
Beam: A cylinder of wood or metal, usually with a circular flange on each end, on which warp yarns are wound for slashing, weaving, and warp knitting.
Benzyl alcohol: chemical used to dye and crystallise uncrystallised fibres. See Carrier.
Blends: refers to the combination of different fibres in a spun yarn.
Braiding: The intertwining of three or more strands to make a cord. The strand form a regular diagonal pattern down the length of the cord.
Break-open resistance: see Non-break-open protection.
Break factor: A measure of yarn strength calculated as: (1) the product of breaking strength times indirect yarn number, or (2) the product of breaking strength times the reciprocal of the direct yarn number.
Break spinning: A direct spinning process for converting manufactured fiber tows to spun yarn that incorporates prestretching and tow breaking with subsequent drafting and spinning in one operation.
Breaking length: A measure of the breaking strength of a yarn; the calculated length of a specimen whose weight is equal to its breaking load. The breaking length expressed in kilometers is numerically equal to the breaking tenacity expressed in grams-force per tex.
Breaking load: The maximum load (or force) applied to a specimen in a tensile test carried to rupture. It is commonly expressed in grams-force (kilograms-force), pounds, or newton’s. (Also see Breaking strength: The maximum resultant internal force that resists rupture in a tension test. The expression “breaking strength” is not used for compression tests, bursting tests, or tear resistance tests in textiles. 2. The load (or force) required to break or rupture a specimen in a tensile test made according to a specified standard procedure.
Breaking tenacity: The tensile stress at rupture of a specimen (fiber, filament, yarn, cord, or similar structure) expressed as newtons per tex, grams-force per tex, or gram-force per denier. The breaking tenacity is calculated from the breaking load and linear density of the unstrained specimen, or obtained directly from tensile testing machines which can be suitably adjusted to indicate tenacity instead of breaking load for specimens of known linear density. Breaking tenacity expressed in grams-force per tex is numerically equal to breaking length expressed in kilometers.
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 THERMO-MAN® mannequin is used to predict the level and location of burns following exposure of the mannequin to a simulated flash fire.
Cabled yarn: A yarn formed by twisting together two or more plied yarns.
Carbon fiber: a high modulus synthetic fiber made from an acrylic containing carbon, hydrogen and nitrogen atoms that is heated in three successive stages to eliminate all but the carbon atoms. It is naturally black in color and is essentially unaffected by UV exposure. First used successfully in the America’s Cup, carbon fiber laminates provide exceptionally low stretch for their weight. Recent manufacturing advances have led to improved fiber flexibility, which translates to longer sail life in exchange for lower modulus numbers.
Carbonisation: a stage of decomposition as the result of exposure to heat.
Card: A machine used in the manufacture of staple yards. Its functions are to separate, align, and deliver the fibers in a sliver form and to remove impurities. The machine consists of a series of rolls, the surfaces of which are covered with many projecting wired or metal teeth. Short staple systems employ flat strips covered with card clothing rather that small rolls
Carrier: chemical which aids the dye to penetrate the dye sites during the coloration of NOMEX® fibres. Is also the agent responsible for the crystallysation of NOMEX® III fibres. See Benzyl Alcohol.
Cationic dyes: class of coloration medium recommended for the dyeing of uncrystallised 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: Degree of resistance of a material to chemicals, such as acids, bases, solvents, oils, and oxidizing agents, and to chemical reactions, including those catalyzed by light.
Coating: The application of a semi-liquid material such as rubber, polyvinyl chloride, or polyurethane to one or both sides of a textile material. Once the coating has been dried (and cured, if necessary), it forms a bond with the fabric.
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 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.
Colour fastness: Resistance to fading; i.e., the property of a dye to retain its color when the dyed (or printed) textile material is exposed to conditions or agents such as light, perspiration, atmospheric gases, or washing that can remove or destroy the color. A dye may be reasonably fast to one agent and only moderately fast to another. Degree of fastness of color is tested by standard procedures. Textile materials often must meet certain fastness specifications for a particular use.
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 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)
Composite: 1. An article or substance of two or more constituents, generally, with reinforcing elements dispersed in a matrix or continuous phase. 2. Hard or soft constructions in which the fibers themselves are consolidated to form structures rather than being formed into yarns. Rigidity of these constructions is controlled by the density, the modulus of the load-bearing fibers, and the fraction of fusible fibers. Strength is controlled by adhesion and shear-yield strength of the matrix unless fibers are bonded in a load-transferring matrix. 3. A structure made by laminating a nonwoven fabric with another nonwoven, with other materials, or by impregnating a nonwoven fabric with resins.
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 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.
Core spinning: The process of making a corespun yarn. It consists of feeding the core yarn (an elastomeric filament yarn, a regular filament yarn, a textured yarn, or a previously spun yarn) into the front delivery roll of the spinning frame and of covering the core yarn with a sheath of fibers during the spinning operation.
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.
Creel: 1. A framework arranged to hold slivers, rovings, or yarns so that many ends can be withdrawn smoothly and evenly without tangling. 2. A similar device used to aggregate sub-tows to tows in manufactured staple processing, especially polyester.
Creep: a stress-strain relation with memory and irreversibility
Crimp: 1. The waviness of a fiber expressed as crimps per unit length. 2. The difference in distance between two points on an unstretched fiber and the same two points when the fiber is straightened under specified tension. Crimp is expressed as a percentage of the unstretched length. 3. The difference in distance between two points on a yarn as it lies in a fabric and the same two points when the yarn has been removed from the fabric and straightened under specified tension, expressed as a percentage of the distance between the two points as the yarn lies in the fabric.
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.
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.
Denim: A firm 2 x 1 or 3 x 1 twill-weave fabric, often having a whitish tinge, obtained by using white filling yarns with colored warp yarns. Heavier weight denims, usually blue or brown, are used for dungarees, work clothes, and men’s and women’s sportswear. Lighter weight denims with softer finish are made in a variety of colors and patterns and are used for sportswear and draperies.
Dip coating: The process of passing a fabric through a solution of resin or elastomer, then through squeeze rolls to remove excess and leave a thin surface layer on the base fabric. In this process, both sides can be coated in one pass.
Dry cleaning: is any cleaning process for clothing and textiles using a chemical solvent other than water. The solvent used is typically tetrachloroethylene (perchloroethylene), abbreviated “perc” in the industry and “dry-cleaning fluid” by the public. It is often used instead of hand washing delicate fabrics, which can be excessively laborious..
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 fibres.
Dyneema®: an UHMwPE (Ultra High Molecular weight Polyethylene) fibre developed by DSM in the Netherlands. An ingredient material in many of our ropes, Dyneema® is light weight and renowned as “The World’s Strongest FibreTM”
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.
Ecru: textile terms meaning undyed or natural in colour
Elasticity: The ability of a strained material to recover its original size and shape immediately after removal of the stress that causes deformation.
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.
Elongation at break: The increase in length when the last component of the specimen breaks.
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
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: A fiber of an indefinite or extreme length such as found naturally in silk. Manufactured fibers are extruded into filaments that are converted into filament yarn, staple, or tow. FILAMENT COUNT: The number of individual filaments that make up a thread or yarn.
Filament number: The linear density of a filament expressed in units such as denier or tex.
Filament winding: In the fabrication of composites, the process of placing reinforcing fibers over a rotating form, (mandrel) to make the product shape. Prepreg fibers or dry fibers that are treated in a resin bath immediately prior to winding may be used. The wound form can be cured or consolidated after the fiber winding is complete to product specifications.
Filament yarn: A yarn composed of continuous filaments assembled with or without twist.
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. 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.
Gell Spinning: also known as dry-wet spinning, is used to obtain high strength or other special properties in the fibers. The polymer is in a “gel” state, only partially liquid, which keeps the polymer chains somewhat bound together. These bonds produce strong inter-chain forces in the fiber, which increase its tensile strength. The polymer chains within the fibers also have a large degree of orientation, which increases strength. The fibers are first air dried, then cooled further in a liquid bath. Dyneema® is produced via this process.
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.
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.
IFR: abbreviation for “inherently flame resistant fibres”, a term most commonly used in the USA. IFR fibres such as NOMEX® and KEVLAR® are able to resist combustion without the aid of chemical additives or treatments, i.e. they have permanent flame resistant properties.
KEVLAR®: Du Pont’s registered trademark for its high-strength para-aramid fibre. One of the most important manmade organic materials ever developed, 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 KEVLAR® fibres is its strength – more than five that of steel at equal weights. 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. KEVLAR® is also heat and flame resistant and enables fabrics made from NOMEX® fibres to resist shrinkage and stay during high temperature exposures. Du Pont recommends the inclusion of KEVLAR® fibres in all 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. NOMEX® brand fibre ´knits´ are available for polo-shirts, jogging suits, hoods, knitted liners and underwear.
Laundering: To wash (clothes, for example).
LCP: See Vectran®
Lightfastness: measure of the extent to which the colour of any material changes after exposure to ultra violet light. In Europe, lightfastness 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.
Limited Flame Spread: CEN test method for evaluating the flammability of the vertical flame test procedure.
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 measure. 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.
Moisture regain: water suspended in the atmosphere which may be absorbed by textile materials.
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®.
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. 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.
NOMEX® III: NOMEX® III is Du Pont´s registered trademark for its patented blend of 95% NOMEX® and 5% KEVLAR® fibres. KEVLAR® from the ´steel-like grid´which helps to keep fabrics intact during exposure to intense heat and flame. The NOMEX® III fibre blend can be dyed by specialists commercial dye houses, weavers and spinners. After more than 25 years, NOMEX® III is still the only fibre blend of its type commercially available on the marked. Due to its all round strengths, the NOMEX® III fibre blend is used for a wide range of garments where thermal protection is required.
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 NOMEX® / FR-Viscose blends. For coveralls and trousers, Du Pont recommends a 50/50 blend, a fabric weight of 250g/m² and a 2×1 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, NOMEX® consolidates and thickens when exposed to a high temperature heat source. The presence of KEVLAR® in the fibre blend then prevents this swollen fabric from breaking open. Well engineered fabrics made from one of the NOMEX® family of fibres which also contain KEVLAR® maintain the all important protective barrier even during exposure to extremely high temperatures.
Oleophobol: registered trademark for water and oil repellent treatments manufactured by Ciba-Geigy. Being based on the PTFE formulation of Du Pont´s TEFLON® water and oil repellent treatment.
P 140: Du Pont fibre composed of a carbon core and polyamide sheath. P140 is used as the antistatic agent in a number of 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 AramidsPBO: See Zylon®
PEN Fiber: See Pentex®
Pentex®: A modified polyester (polyethylene naphtha late) fiber, Pentex has 2.5 times less stretch than standard polyester fibers (between polyester and Kevlar 29). It does not shrink as much as a good Dacron fiber (5% vs. 15%).
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 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: A manufactured fiber introduced in the early 1950s, polyester is the most common fiber used in sailcloth. It is most commonly referred to by its DuPont trade name Dacron®, the name given to the Type 52 high modulus fiber made specifically for sailcloth. Recent advancements by Allied Signal have produced a fiber called 1W70 polyester that has a 27% higher tenacity than Type 52. Other polyester trade names include Terylene®, Tetoron®, Trevira® and Diolen®. Polyester’s desirable properties include relatively high resiliency, high abrasion resistance, high UV resistance, high flex strength and low cost. Low absorbency allows the fiber to dry quickly.
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 fire 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 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 470/1Protective clothing for use in welding and allied processes
- EN 531Protective clothing for workers exposed to heat
- EN 533Protective clothing – Protection against heat and flame – Limited flame spread materials and material assemblies
- EN 1149/3Protective clothing – Electrostatic properties – Part 3: Test method for measurement of charge decay.
Quality: the extent to which products, services, processes, and relationships are free from defects, constraints, and items which do not add value for customers
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 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. NOMEX® OUTERSHELL TOUGH Rip-Stop is the name given to a fabric in which reinforcing coloured aramid threads are introduced at regular intervals in a 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 NOMEX® OUTERSHELL TOUGH fibre blend. See Pyjama check.
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 NOMEX® and 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 NOMEX® family of fibres can be purchased. Regularly updated by Du Pont as a service to end users as well as to industry.
Spectra®: Ultra-high-molecular-weight polyethylene (UHMWPE or sometimes shortened to UHMW) fiber, also known as high-modulus polyethylene (HMPE) or high-performance polyethylene (HPPE) produced by Honeywell and competing with Dyneema®
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.
Tear strength: the ability of a cut fabric to resist tearing or ripping.
Tenacity: refers to the strength of a fibre, yarn or fabric.
Technora®: is an Aramid that is useful for a variety of applications that require high strength or chemical resistance. It is a brandname of the company Teijin.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 NOMEX® fibre blends containing 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.
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, 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 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.
UHMWPE:Ultra-high-molecular-weight polyethylene is a subset of the thermoplastic polyethylene. It has extremely long chains, with molecular weight numbering in the millions, usually between 2 and 6 million. It is used to make very strong fiber like Dyneema® and Spectra®.
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 NOMEX®.
Underwear: of primary importance is that the materials used have a high melt point. 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 NOMEX® range of fibre products remain unchanged after periods of extensive exposure. As with all coloured products the one area of exception is lightfastness
Vectran®: is a manufactured fibre, spun from a liquid crystal polymer created by Celanese Acetate LLC and now manufactured by Kuraray Co., Ltd. Chemically it is an aromatic polyester produced by the polycondensation of 4-hydroxybenzoic acid and 6-hydroxynaphthalene-2-carboxylic acidVelcro: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 NOMEX® fibres, the hooks and loops from a heavy duty nylon. Garments made from one of the 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.
Warp: the vertical yarns in a fabric, running parallel to the selvage edge.
Washfastness: the stability of a fabric after washing under recommended conditions, KEVLAR® including dimensional and colour stability. The washfastness of NOMEX® or NOMEX® based fabrics is excellent, contributing to the exceptional wear life of garments made from one of the 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.
Yarn dyed: refers to the trade dying process of introducing the colour into a spun yarn.
Zipper: to help reduce potential burn injuries to the minimum it is important that all accessories of a FR garment be non-flammable. Zippers backed with fabrics made from NOMEX® fibres are available.
Zylon®: Zylon (poly(p-phenylene-2,6-benzobisoxazole/ PBO) is a trademarked name for a range of thermoset liquid crystalline polyoxazole. This synthetic polymer material was invented and developed by SRI International in the 1980s, and is currently manufactured by the Toyobo Corporation.