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Carpeting Terminology & Definitions

Use the tabs to locate definitions for common terms and words related to carpets.

Abrasion Resistance
A measure of the pile fiber's ability to withstand wear.

Acid Dyeable Nylon
A modified nylon polymer able to receive acid dyes. Acid dyeable yarns are available in light, medium and deep dye levels.

Any of several chemical compounds used to bond the secondary backing to the carpet. These substances also bond the tufted yarn into the carpet.

Adipic Acid
A base ingredient in the production of Type 6,6 nylon. Adipic acid has a chain of six carbon atoms. It is reacted with hexamethylene diamine (also having six carbon atoms) to polymerize Type 6,6 nylon.

Properties perceived by touch and sight, such as the hand, color, luster and texture of carpet.

A chemical attraction between components that causes them to combine. An example is the affinity of acid dyes for nylon fiber.

(also known as intermingling, commingling or heathered): A method of producing yarn by combining two or more BCF fibers together. Fibers are "locked" together via air jets at regular or irregular intervals. Various air-entangling processes exist making it possible to produce a wide range or aesthetics in finished yarns, from highly blended, near solid looks to yarns where individual colors are accented and color separation mimics that of plied yarns.

Amine End Groups
The terminating (-NH2) group of a nylon polymer chain. Amine end groups provide dye sites for nylon (polyamide) fibers.

A microbe killing agent applied to carpet.

Antistatic Properties
Resisting the tendency to produce annoying static electric shocks in situations where friction of the foot tread builds up static in low-humidity conditions. Some nylon fibers introduce a conductive filament in the yarn bundle to conduct or dissipate static charges from the human body. Olefin fiber is inherently static-resistant, as it is similar to the surface of most shoe soles (only dissimilar surfaces rub to create a static charge).
There are two basic methods for controlling the buildup of static in nylon carpets:

  1. Treating the carpet with a topical spray. This is not permanent and creates a tendency for the carpet surface to soil.
  2. Adding a carbon composite nylon filament into the bundle of yarn to act as a dissipating rod carrying the static charge away from the person generating it.

Atmospheric fading test
A test that indicates a change of shade or hue of dyed fabric caused by a chemical reaction between certain dyes and acid gases. Recommended test methods for carpets (AATCC 129 - Ozone and AATCC 164 - Oxides of Nitrogen) would specify a minimum rating, after two cycles, of no less than International Gray Scale for Color Change rating of 3.


  1. An oven-like apparatus for use in yarn heatsetting operations. Under pressure in a superheated steam atmosphere, yarn is given a "memory" of its twist. Autoclave heatsetting is a batch, not a continuous, method.
  2. An pressurized, heated apparatus used for making polymer.

Average Pile Density
See "Density."

A weaving method originating in the eighteenth century in Axminster, England. In this method, individual pile tufts are inserted from spools of colored yarns, making possible an almost endless variety of colors and geometric or floral patterns.

Back Coating
An adhesive applied to the back of a carpet to lock pile yarn tufts into a carpet backing, bonding a secondary backing to a primary backing. This increases the fabric body or stiffness, and increases the carpets dimensional stability.

Materials comprising the back of the carpet, as opposed to the carpet pile or face.

— For Fusion Bonded Carpets: Backing material for fusion-bonded carpet is a system of layered vinyl or plastic compound and fiberglass scrim for dimensional stability.

— For Tufted Carpets: Two backings, a Primary back consisting of a woven or nonwoven fabric in which the pile yarn is inserted by the tufting needles. Also a Secondary back, which is fabric laminated to the back of carpet to reinforce and increase dimensional stability.

— For Woven Carpets: Backings of woven carpets are the "construction yarns" comprising chain warp, stuffer warp, and shot or fill, which are interwoven with the face yarn during carpet fabric formation.

Backing fabric
A fabric into which a pile yarn is inserted or a reinforcing layer which is adhered to the reverse side of a fabric.

Backing systems
— Attached cushion: Padding, such as foam rubber or polyurethane, that is made as an integral part of the backing.

— Conventional backing: Carpet with a primary and secondary latex-laminated woven or nonwoven fabric.

— PVC hard-backed or closed-cell PVC (polyvinyl chloride): Used mostly in carpet tile or 6' wide goods due to its weight and stiffness. PVC gives a stiff, stable backing with little cushioning but excellent tuft bind and stability.

— Thermoplastic: A molten resin process that permanently adheres the primary and secondary backing.

— Unitary: A single lamination of fabric backing with high rubber content latex or hot-melt resin compound for increased tuft bind. Used primarily with loop pile carpet.

— Urethane (Polyurethane): A polymeric resin applied by the carpet mill in the finishing process. In the heat and curing chamber it reacts and creates a foam-like texture. This backing encapsulates the yarn for extra tuft bind with a cushion attached.

A container (bag, sack, square, box, package) of anywhere from 650-850 lbs. of staple fibers, wrapped and ready to be shipped to the yarn spinner or carpet mill with yarn-spinning capacity.

BCF yarn
An abbreviation for Bulked Continuous Filament yarn referring to synthetic fibers in a continuous form. BCF yarn can be used in cut or loop pile construction.

A large cylinder or spool on which carpet yarns, usually pre-dyed, are wound prior to feeding onto tufting, weaving or fusion bonding equipment.

Beam dyeing machine
A machine for dyeing yarns that have been wound onto a special beam that has evenly perforated holes along its barrel. The dye is forced through the barrel into the yarn from inside to outside and vice versa.

Beck dye
Dyeing of tufted greige carpet in a large vat of dye liquor. In this process, the carpet roll is sewn into a loop and then is continuously rotated and immersed in the heated vat for several hours. Most commonly used for cut pile carpet, it offers good custom color flexibility. (See "Dye methods.")

A loop pile design originally comprised of natural colored, bulky wool yarns in a woven construction. Contempory berber is constructed primarily of bulky, loop pile, nylon, or polypropylene yarns in a tufted construction. This style originates from a nomadic North African tribe called the Berbers.

Loss of color by a fabric or yarn when immersed in water or a solvent, as a result of improper dyeing or the use of dyes of poor quality. Fabrics that bleed will stain white or lightly shaded fabrics that come in contact with them when wet.

A mixture of two or more fibers or yarns.

The mixing of staple fibers before they are carded, drafted and spun into yarn. Blending is done for consistency in the final yarn and is a critical step to avoid "streaks" in a carpet.

The opposite of dull or matte when describing luster.

Denotes carpet tufted or woven in widths six feet or greater.

A carpet or rug in which a raised pattern or engraved effect is formed using heavy twisted yarn tufts on a ground of straight fibers.

Bulk Development
The process of a textured or latent crimp yarn to achieve maximum bulk. Carpet fibers develop maximum bulk during wet processing such as dyeing.

Also known as crimping, texturizing or lofting. Bulking imparts texture/fullness to the fiber or yarn during production. Bulking is done to increase the coverage the yarn will have in the carpet face. Bulking also adds to fiber resiliency. See "Texturizing."

Cabled Yarn
A yarn formed by twisting together two or more plied yarns.

The single basic ingredient in the production of Type 6 nylon. Caprolactam has a chain of six carbon atoms. It is a petrochemical.

The step after blending in the staple spinning process which combs out the loose fibers and arranges them in orderly strands called sliver. Sliver is drawn and blended, then twisted and further drawn into yarns.

Dr. Wallace Carothers
The inventor of nylon. Dr. Carothers invented nylon in 1938. He first developed and refined Type 6,6 nylon.

Carpet Tile
(See "Modular carpet or tile.")

Cationic Dyeable Nylon
Nylon polymer that has been modified chemically to make the fiber receptive to cationic (basic) dyes. Cationic dyeable yarns are used in conjunction with acid dyeable yarns to produce multicolors in piece dye methods.

The ability or degree that a stain is removed from a carpet.

Color Matching
The process of comparing colors, either by eye or by instrument, and making adjustments if necessary, with the intent of reducing differences between the item being colored and the standard. Critical to color matching are:

  1. The light under which the colors are compared. (The light source being used in the real conditions of the commercial environment should be used to match colors).
  2. The surface texture of the object being matched (cut pile carpet can appear darker than loop made of the same yarn).
  3. The surface luster of the object being matched (higher luster yarn can look darker than lower luster fibers).

The ability of a carpet or fiber to retain color when exposed to (1) ultraviolet light, (2) crocking (wet or dry), or (3) atmospheric conditions (according to manufacturers' and government test standards).

Commercial Matching
Matching of colors within acceptable tolerances or with a color variation that is barely detectable to the naked eye.

Commingled Yarn
see "Air Entangling"

Computer Grade Carpet
This term generally refers to carpet products that are said to be "safe" for use around computers of all types, due to low static generation. In some cases, this term may be used in connection with a true ESD carpet product whereas in other cases the carpet product may not meet those requirements. The development of permanent static control in commercial carpet products and static-damage-resistant electronics for computers and other electronic devices (phones, faxes, PDAs, CD and MP3 players, etc.) has eliminated the need for "computer grade carpet" in any application that does not fit the requirements for a true ESD carpet product (see "ESD (Electrostatic Discharge carpet").

The carpet manufacturing method, usually tufted, woven or bonded. The term also can refer to the specific details of a particular carpet's specification, including fiber type, yarn twist level, density, method of dyeing, etc.

Continuous Dyeing
Dyeing of carpet (greige) while it travels continuously through a dye range. The process is frequently referred to by the name of one of the prime machinery manufacturers, Eduard Kuster (pronounced "Kooster"). Continuous dyeing can produce multicolored or solid-colored carpet. Multicolored carpet is achieved by using cross-dyeable yarns or with various accessories that can give a pattern or overprint. Advantages include large dye lots, relatively low cost and color flexibility. However, this method is more critical than beck dyeing or yarn dyeing for side-to-side matching consistency (the carpet must be installed in roll sequence). (See "Dye methods.")

Continuous Filament
Unbroken strand of synthetic fiber, such as filament nylon or olefin. Nylon and olefin are made by extruding molten polymer through a spinnerette (similar to a showerhead). The fibers are cooled, then stretched and textured into bundles referred to as yarn. This yarn can be plied or commingled with other yarn and then tufted.

Continuous Heatsetting
The process of applying heat to yarns to "set" or retain bulk, twist and spring introduced by spinning and/or twisting. Continuous heatsetting can be applied to staple or continuous filament yarns. The two primary types of continuous heatsetting equipment are the Superba, which uses steam and pressure, and the Suessen, which uses dry heat. (See "Heatsetting.")

An intermediate that usually buys raw fiber, processes it to a carpet manufacturer's specification, then sells the finished product to the carpet manufacturer.

Cotton Count
The yarn numbering system based on length and weight originally used for cotton yarns and now employed for most staple yarns. It is based on a unit length of 840 yards, and the count of the yarn is equal to the number of 840-yard skeins required to weigh one pound. Under this system, the higher the number, the finer the yarn. A typical carpet yarn might be a three cotton count two plied, written as 3.0/2c.c.

The rack or frame located behind a tufting machine which holds the cones of pile yarn that feed into the needles of a tufting machine.

In fiber, a nonlinear configuration, such as a sawtooth, zigzag or random curl relative to the fiber axis. Most synthetic fibers, both staple and filament, used in carpets are crimped. Fiber crimp increases bulk and cover and facilitates interlocking of staple fibers in spun yarns. (See "Texturizing.")

The resistance of transfer of colorant from the surface of a colored yarn or fabric to another surface, or to an adjacent area of the same fabric, principally by rubbing.

The removal of dye from a fabric by rubbing. Crocking can be caused by insufficient dye penetration or fixation, the use of improper dyes or dyeing methods, or insufficient washing and treatment after the dyeing operation. Crocking can occur under dry or wet conditions.

Cross Section
The shape of a fiber when cut perpendicular to its axis. Man-made fiber cross sections vary to produce a wide variety of physical effects such as soil-hiding characteristics, soil releasing, luster, and fineness or coarseness. The most advanced carpet filament cross section is the four-hole hollow filament. The most advanced carpet staple cross section is the modified delta.

The collapsing of pile yarns, resulting in carpet matting and loss of resilience. This form of carpet failure usually occurs in the areas of heaviest traffic. It is also called "matting" and "walking out." It can be minimized by the use of more resilient fibers, denser construction, somewhat higher weight and (in cut pile) with higher tuft twist and proper heatsetting.

Curvilinear Crimp
The three-dimensional crimp patented by INVISTA for its bcf yarn. This texture is added to the yarn by a series of air jets. Curvilinear crimp gives consistency, bulk and spring-back memory that is needed in the manufacture of cut pile filament carpets and streak-free loop carpets (see "Texturizing").

Cushion-Backed Carpet
Carpet having a cushion, padding or underlay material as an integral part of its backing.

Cut and Loop Pile
Carpet whose face shows a pattern, either geometric or floral, made up of a combination of loop pile tufts and cut pile tufts. Also called cut/uncut. The carpet can be dyed solid or multicolored.

Cut Pile
A pile surface created by cutting the loops of yarn in a tufted, woven or fusion-bonded carpet.

Dead yarn
That portion of a yarn that is submerged in the backing of a textile fabric which does not contribute directly to aesthetics or wearability of the fabric.

Separation of the secondary backing from the primary backing.

The process of reducing the brightness of a synthetic fiber yarn or fabric, such as by adding chemicals or darker pigments to the dyes. This process helps minimize the appearance of soiling in the carpet.

A weight-per-unit-length measure of filament fibers or yarns. Denier is numerically equal to the weight in grams of 9,000 meters of fiber. Denier is a direct numbering system in which the lower numbers represent the finer sizes and the higher numbers the coarser sizes. The term is derived from the French silk industry, a denier was an old French silver coin. In the U.S., the denier system is used for numbering filament yarns and man-made fiber staple (but not spun yarns).

A measure of mass per unit of volume. In the carpet world: the weight of pile yarn in a unit volume of carpet.

Differential Dyeability
Fibers which have different dye affinities combined together to produce multicolor carpet from a single dyeing.

Dimensional Stability
The ability of carpet to retain its size and shape once installed. Dimensional stability is obtained in tufted carpet by the application of a secondary back.

A set of full-size yarn packages produced by one filament extrusion (spinning) machine.


  1. Stretching synthetic fiber after extrusion to align molecules. This process gives fibers greater tensile strength. This is done in synthetic fiber production after the molten fiber strands harden.
  2. Pulling and thinning of sliver (combed staple fiber strands) in the spinning of staple yarn prior to being spun into yarn.

Drop Match
A drop match is a pattern that repeats across the carpet diagonally or at a 45-degree angle to the edge of the seam.

Dye Lot
A quantity of carpet dyed at one time or made from yarn dyed at one time which is consistent in color throughout the fabric. Dye lot size varies with dye method and the capability of dyeing equipment.

Dye Methods

— Beck dyed
A method of batch dyeing carpet. A piece dye method. The carpet is sewn into a loop, then hung on a large reel in the dye beck unit which moves the carpet through the dye liquor. This process is continued for a set time and achieves excellent color uniformity throughout the carpet.

— Continuous or "Kuster" dyed
A method of continuously dyeing carpet. A piece dye method. Kuster manufactures a continuous dye machine that is commonly used. Printing is another continuous dyeing process. Large lots of a single dye series are possible with continuous dyeing, but side- to- side color consistency should be verified.

— Continuous solid color dyed
A process of dyeing singles or plied yarn using dye rolls. The application of dye is similar to continuous space dye process except that a single color is applied to the yarn. These solid color yarns can be tufted into multicolored carpets.

— Package dyed
This is similar to skein dyeing inasmuch as undyed yarn is wound on perforated tubes and the packages are dyed by passing dye liquor through the packages under pressure.

— Pad dyed
A process of dyeing carpet, yarn or fiber stock continuously. The material to be dyed passes through a trough containing the dye liquor and then between heavy rollers which squeeze the dye liquor evenly into the material.

— Skein dyed
A method of dyeing yarn. Undyed spun or filament yarns are plied and heatset, then reeled into skein form and dyed in skein dye kettles.

— Solution dyed
Pigment is added to the molten polymer from which the filaments are made. The fiber is extruded in colored form.

— Space dyed
A method of dyeing yarn. Space dye refers to yarn with multiple colors printed on each strand. There are three basic processes used to create this effect: the warp system, the knit-de-knit process and the continuous dye process.

  1. In the warp system, multiple strands of yarn are continuously printed at spaced intervals with different colors. These yarns usually have "long" spaces of each color. Typical color lengths are 3/4"-7" with longer lengths becoming popular in carpets with strie aesthetics.
  2. In the knit-de-knit process, the yarn is first knitted into a tubular fabric (sock), dyed to a solid color and then overprinted with up to seven different colors. These yarns usually have "short" (1/8"-1/4") spaces of color.
  3. In the continuous dye process, yarn is dyed as singles or plied yarn and color is applied either by air jet or dye troughs. This process allows for yarns to have either long or short spaces of color

Dye Site
Irregular, electrically charged area on a fiber surface that has an affinity for dye.


  1. An individual fiber making up a yarn to be tufted into carpet.
  2. An individual pile yarn in a tufted carpet or a roll.
  3. An end or short length of carpet or remnant.

ESD Carpet
Electrostatic Discharge Carpet is specially constructed to meet the requirements for an ESD-controlled environment, which is generally restricted to applications involving electronic-component assembly or where electronic components and/or circuit boards are routinely handled. In an ESD-controlled environment, the static generated by walking on the floor must typically be less than 0.2 kV (200 volts). An ESD-controlled environment requires the use of special ESD shoes, and generally includes the use of electrically-grounding wrist straps, special grounded work surfaces, ESD smocks over clothing, and control of humidity within the range of 40-60% RH. ESD carpet incorporates electrically-conductive elements which connect to a conductive backing, which is glued to the floor with special conductive adhesive, then carefully connected to the building ground at specified intervals. The use of electronic equipment, computers, digital phones, etc., in a typical commercial space does not require the use of ESD carpet, as long as permanent static control is built into the commercial carpet product.

Extra Heavy Traffic
More than 2,000 traffics per day. Could also include some directional, nondirectional, pivoting and rolling traffic, as well as tracked-in dirt. See "Foot traffic units.(See "Foot traffic units.")

Refers to the second stage of nylon production. The process of forcing molten material through a spinnerette (similar to a showerhead). Once exposed to air cooling, the fiber strands harden. It is at the extrusion stage that many of the fiber engineering improvements take place: cross section design, shape, size and

Face Weight
The total weight of the face (above the backing) yarns in the carpet. Typically, this is expressed in ounces per square yard.

A device used to test fading of yarns, carpets, fibers, and other materials. This device uses gas, light or ozone to conduct the fading tests.

Gradual loss of color caused by sunlight or artificial light, atmospheric gases including ozone, nitrogen dioxide and hydrogen sulphide, cleaning and bleaching chemicals such as sodium hypochlorite, and other household and industrial products. Commercial flooring installations in areas where such exposures occur require proper care in selection of colorfast carpet.

Fading tests
Laboratory tests designed to predict the likelihood of carpet fading under actual use conditions. Fading is usually caused either by ultraviolet light or by exposure to ozone gas. Carpet can be tested in laboratory fadeometers for results against fading agents. Dye stuff, hue or fiber can affect fading. A specific carpet being considered for a critical installation should be tested prior to final selection.

A unit of matter, either natural or manmade, that forms the basic element of carpet. The term refers to units that can be spun, plied or air-tangled into a yarn and can be processed by weaving, tufting, knitting or fusion bonding into a carpet. Important properties include recovery, bulk, cover, uniformity, durability, soil resistance, luster, dyeability and denier.

Fiber Engineering
Refers to improvements to the fiber including: polymer characteristics, polymer additives (delusterant or solution dye pigments), cross section design, and fiber finishes (low surface energy fluorochemical coatings for soil release).

Fiber Shape
Refers to the cross section and size of individual filaments. Fiber shape impacts soil hiding and soil release (cleanability).

Fiber Size
Refers to the denier per filament (dpf) or thickness of a filament.

Fiber which has been extruded and is then converted into yarn fiber, staple, or tow.

Filament Count
The number of individual filaments that make up a thread or yarn.

A general term referring to the processing of carpets after tufting, weaving and dyeing. Processes include application of secondary backing, application of attached foam cushion, application of soil-resistant treatment, shearing, brushing, dying, printing and others.

Flame Resistance Tests
(also known as Flammability tests.) Procedures that have been developed for assessing the flame resistance of carpets. The most commonly accepted are: Methenamine Pill Test - A carpet flammability test described in federal regulations CPSC 1-70 and CPSC 2-70. It measures the size of burn hole produced by an ignited methenamine tablet. Also used on the back of carpet. All carpet sold in the U.S. must pass the CPSC 1-70 flammability test. Radiant Panel Test - A test for the flammability of carpets or rugs in which the specimen is mounted on the floor of the test chamber and exposed to intense radiant heat from above. The rate of flame spread is assessed. (ASTM-E-648 Class I .45 watts/cm; Class II .22 watts/cm.)

A material that burns slowly or is self-extinguishing after removal of an external source of ignition. A fabric or yarn can be flame resistant because of the innate properties of the fiber, the twist level of the yarn, the fabric construction, or the presence of flame retardants, or because of a combination of these factors.

Fluorine Analysis
A measurement of the amount of soil resistance chemical (fluorochemical) applied to the fiber during the carpet manufacturing process. This can be performed for the initial application of the fluorochemical as well as for the durability of the chemical to remain after hot water extraction cleaning.

Fluorochemical soil/stain repellent
Fabric protectors designed to reduce soiling and repell water and oil based stains.

Foot Traffic Units
One foot traffic unit is described as a pedestrian walking across a measured section of carpet, one time. Foot traffic is classified as follows:

  • Light: less than 50/day
  • Moderate: 50-200/day
  • Heavy: 200-2000/day
  • Extra Heavy: more than 2000/day
    See individual traffic rating for details.

A general term used for many yarn manufacturing machines. For example: Racks at back of a Wilton loom that hold spools from which yarns are fed into the loom. Each frame holds separate colors, so a three-frame Wilton would have three colors in the design.


  1. A yarn that has been very tightly twisted to give a rough or nubby appearance to the finished carpet pile.
  2. A cut-pile carpet made of highly twisted yarns normally plied and heatset. A kinked or curly yarn effect is achieved.

Fusion Bonding
Fabrication technique for manufacturing carpet for a 6'-wide or modular tile. It uses a thermoplastic process tuft that implants yarn backing in a liquid vinyl knife compound to two backing materials in a sandwich configuration. A knife splits the sandwich to create two carpets simultaneously. Spun yarn is used in this process, and only cut pile carpets are produced.

A hairy effect on the carpet surface caused by fibers working loose under foot traffic or by slack yarn twist. This can be caused by poor latex penetration, poor yarn spinning, poor twisting and heatsetting, or improper carpet and cleaning. Not to be confused with initial shedding, a normal phenomenon associated with spun cut pile construction.

The number of ends of surface yarn counting across the width of carpet. In tufted carpet, gauge is the number of ends of surface yarn per inch counting across the carpet; e.g., 1/8 gauge = 8 ends per inch. In woven carpet, pitch is the number of ends of yarn in 27 inches of width; e.g., 216 pitch divided by 27 = 8 ends per inch. To convert gauge to pitch, multiply ends per inch by 27; e.g., 1/10 surface yarn gauge is equivalent to width 270 pitch, or 10 gauge ends per inch X 27.

Gel dyeing
Passing a wet-spun fiber that is in the gel state (not yet at full crystallinity or orientation) through a dyebath containing dye with affinity for the fiber. This process provides good accessibility of the dye sites.

Graphics Machine
A form of tufting machine capable of producing patterns, usually by the use of shifting needle bars that may be individually controlled, or by individually controlled needles or a combination of the two. Major refinements using computer technology have been engineered into "graphics machines." Each new machine improvement brings tufting patterns nearer to those of woven capability.

Greige Goods
(Pronounced "gray" goods.) Term designating carpet in an undyed or unfinished state.

A condition that occurs when the carpet backing shows through the carpet pile.

How the carpet feels to the touch. Factors determining how the carpet feels include weight, stiffness, fiber type, denier, density and backing.

Term reffering to a skein of yarn.

A subtle multicolored effect produced by commingling yarns or spinning blended fibers of different colors together.

Process for stabilization and setting a memory of twist in plied yarns. Conventional autoclave treats skeins with pressurized steam, usually at temps ranging 240° - 300°F, in a batch operation. Some machines employ a continuous dry heatsetting method, this is used most commonly for spun yarn heatsetting.

Heavy traffic
Term refers to 200 to 2000 traffics per day. Could also include some directional, nondirectional and rolling traffic, as well as tracked-in dirt.

A frame of vertical cords or wires (like needles) through which warp yarns are threaded. The heddle is raised and lowered to interlace face yarns.

A petrochemical compound with a chain of six carbon atoms which is reacted with adipic acid to make Type 6,6 nylon. It is a petrochemical.

Hexapod drum test
A rotating drum used as an instrument to test pile floor coverings. Carpet samples are placed in this rotating drum with a polyurethane studded metal ball to simulate the physical effects of traffic. This accelerated test provides a specific rating of the ability of the carpet to withstand crushing and matting.

Hollow filament fibers
Refers to filaments with interior voids. Hollow core fibers improve the soil-hiding ability of nylon by diffusing light passing through the fiber. Hollow filament fibers should be at least 89% solid polymer so that the interior voids do not weaken the fiber and cause it to fray under heavy wear.

The measure of moisture in the atmosphere.

Hybrid carpet
A carpet in which two or more different yarn types are combined in the carpet construction.

Indoor air quality (IAQ)
A term used to describe the quality of the air breathed by occupants of an indoor or enclosed environment.

Internal Dye Variability
The change in dye uniformity across diameter and along the length of a yarn's individual filaments. Affects appearance of the dyed product and is a function of fiber, dye, dyeing process, and dye bath characteristics.

International Gray Scale for Color Change
A standard comparison to rate degrees of color change from 5 (no change) to 1 (severe change).

International Gray Scale for Staining
A standard comparison to rate degrees of staining from 5 (no stain) to 1 (severe stain).

ISO (The International Organization for Standardization)
A non-governmental, worldwide organization whose work results in international agreements that are published as International Standards.

Uneven cutting of the loops in cut-pile carpets caused by poor adjustment of the knives and hooks or excessive yarn tension.

A device used to bulk yarns by introducing curls, coils and loops that are formed by action of a high velocity stream usually air or steam.

A natural fiber, native to India, which can be shredded and spun into yarn. Jute yarns are used for backing in woven carpets, or itself woven into sheets and used as secondary backing on tufted carpet. In many applications, jute is being replaced by fiberglass, polypropylene or other synthetic fibers.

A fabrication process comprised of interlacing yarns in a series of connected loops with needles, like weaving. Carpet produced by knitting is generally categorized as woven carpet. In carpet knitting, pile and backing are produced at the same time using multiple sets of needles in one operation.

A tightly twisted yarn made from plant fiber, used as a backing yarn.

A trade name of a manufacturer of continuous dyeing machines which apply dye to tufted carpet. (See "Continuous dyeing.")

A water emulsion of synthetic rubber, natural rubber, or other polymer. In carpet, latex is used for laminating secondary backings to tufted carpet, backcoating carpet and rugs, and for backcoating woven carpets and rugs

Level Loop Pile
A woven or tufted carpet style having all tufts in a loop form and of substantially the same height.

Light Traffic
Less than 100 traffics per day. Could also include some directional traffic, but no tracked-in dirt.

The degree of resistance of dyed textile materials to the color-destroying influence of sunlight. Two methods of testing are exposure to sunlight, either direct or under glass, and accelerated laboratory testing in which several types of artificial light sources are used.

Loop Pile
A tufted or woven carpet pile surface where the face yarns are comprised of uncut loops. Loop pile can be level, textured or patterned.

Brightness or reflectivity of fibers, yarns, carpets or fabrics. Synthetic fibers are produced in various luster classifications including bright, semi-bright, semi-dull and dull. The luster of finished carpet depends on heatsetting methods, dyeing and finishing. In high-traffic commercial areas, duller carpet yarns are often preferred for soil-hiding ability.

Severe pile crush and fiber/tuft entanglement.

Melting Point
The temperature at which a carpet fiber changes from a solid to a liquid.

Moderate Traffic
100 to 1,000 traffics per day. Could also include some directional and nondirectional traffic, some pivoting and little tracked-in dirt.

Modular Carpet or Tile
Also called "carpet tile." Generally 18" x 18" squares cut from 6'-wide or broadloom carpet.

A single filament of a synthetic fiber usually of a denier higher than 14. Monofilaments are usually spun individually instead of through a spinnerette.

Multiple continuous synthetic yarns that are extruded together, usually from multiple holes of a single spinnerette. Multifilament yarns are texturized to increase bulk and cover, and are called "bulked continuous filament" or BCF yarns.

Multilevel Loop Pile
A woven or tufted carpet style having some tufts that are substantially longer than others, resulting in a sculptured appearance or pattern.

Refers to the pile surface of a carpet or rug.

Any carpet manufactured by a method other than weaving, but particularly those composed of fibers held together by chemical, mechanical, adhesive or fusion means. The term can also be applied to primary backings.

A petrochemical-based fiber invented in 1938 by DuPont. There are two basic types of nylon: Type 6,6 nylon and Type 6 nylon. Nylon is produced in bulked continuous filament for use in loop carpets and cut pile carpets; and staple nylon which is spun into yarn for use in cut pile carpets. Nylon is the dominant fiber choice for commercial use due to its wear characteristics.

Nylon flake
Polymer that has been cut into small pieces for storage or for immediate melting in the fiber extrusion process.

Nylon—Type 6
Made from one base ingredient: caprolactam. Compared to Type 6,6 nylon, Type 6 accepts dye at a faster rate. The more open molecular structure of Type 6 nylon allows dye stuffs, and stains, to set in more easily.

Nylon—Type 6,6
Made with two base chemical ingredients: adipic acidand hexamethylenediamine. Type 6,6 nylon has a tighter molecular structure, making it harder, more resilient and more resistant to stains than Type 6. In the U.S., over 60% of all nylon carpets installed are Type 6,6 nylon.

Olefin Fiber
A fiber made from a by-product of gasoline refining, consisting of one ingredient: propylene. Since propylene is widely available at a comparatively lower cost than nylon base ingredients, olefin is less expensive than nylon. Olefin does not accept water-based dyes or stains. Color is added in the manufacturing process in the form of pigment. Olefin is a lightweight fiber and can have good bulk and cover. However, the polymer base creates a soft fiber which has poor resiliency, a lower melting point and poor texture retention as compared to nylon. The carpet fiber is available as bulked continuous filament yarn. Only when budget is the main consideration, lower life expectancy is anticipated, and long-term appearance retention is not a priority, olefin can be considered.

Optimum Twist
The term used to describe the amount of twist that gives the maximum breaking strength or the maximum bulk of a carpet.

Ozone Fading
The fading of color from a dyed or pigmented fiber caused by atmospheric contaminants of ozone.

Package Dyed
Similar to skein dyeing, package dyeing is a yarn coloration process. Yarns are wound onto perforated tubes in package dye machines which are either pressurized or atmospheric. Dye liquor is circulated by reversible pumps which force it through the yarn both from package center outward and inward towards the center in two or more cycles to achieve level dyeing. Although package dyeing is well established in textiles, it is seldom used for carpet yarns. This is due to the fact that tightly wound dye package inhibits yarn bulk development.

Parallel Spinning
Spinning method most commonly used in spinning nylon staple fiber into yarn. Staple fibers measuring 6" to 8" are paralleled by combing and drafting until the fibers are in regular even slivers, or strands of combed yarn. Multiple slivers are combined to make up one finely drafted sliver. This sliver can be further blended for extreme consistency. The final sliver is put on a spinning frame and further drawn (or pulled) as twist is applied, turning the fiber into a cohesive singles yarn ready to be plied and heatset.

Pattern Match
Lining up patterned carpet in such a way that the design element is continued across seams, making the finished installation appear cohesive. Patterns must be matched in the same way as they appear on the carpet itself either in a set match or drop match.

Pattern Streaks
Visually apparent streaking in patterned carpet resulting from linear juxtaposition of pattern elements in one direction. It is usually most visible in the length direction. It is not a carpet defect, but is inherent in certain designs. Contract specifiers should view rolls of carpet laid out on a floor to evaluate geometric or other busy patterns for this characteristic which may be objectionable in long corridors and other large areas, but not visible in small rooms.

Patterned Loop
A woven or tufted carpet style having all tufts in a loop form (either level or textured) in either a defined or random pattern and design.

Picks per inch
In woven carpet and fabric, the number of fill yarns per inch of length.

Piece Dyed
A method in which tufted carpet is dyed, as opposed to yarn dye methods in which color is added to yarn before tufting.

Highly colored, insoluble substance used to impart color to other materials. White pigments, e.g., titanium dioxide, are dispersed in fiber polymers to produce delustered (semi-dull and dull) fibers. Colored pigments are added to polymer to create producer colored or solution dyed yarns.

Pigmented Yarns
Dull or colored yarn spun from a solution to which pigment has been added.

The visible surface of carpet, consisting of yarn tufts in loop and/or cut configuration. Also called the face or nap.

Pile Crush
Loss of pile thickness by compressing and bending of tufts caused by foot traffic and heavy furniture. The tufts collapse into the space between them. It may be irreversible if the yarn has inadequate resilience and/or the pile has insufficient density for the traffic load.

Pile Height
The length of the tufts measured from the primary backing top surface to their tips. Pile tufts should be gently extended but not stretched during accurate measurement. This specification is expressed in fractions of an inch or decimal fractions of an inch in the U.S.

Pile Reversal
A persistent change in the direction of the pile lay in certain areas resulting in an apparent visual difference of shade. Also known as watermarking, pooling or shading.

Pile Thickness
The resulting thickness when the thickness of the backing is subtracted from the total thickness of the finished carpet.

Pile Weight
The weight in ounces of the fiber in a square yard of carpet.

Pile Yarn
The yarn making up the tufts of the carpet.

The tendency of fibers to work loose from a surface and form balled or matted particles that remain attached to the surface of the carpet.

Pin Drafter
A mechanism used in parallel spinning to orient the fibers by using combing pins and rollers.

A smooth, highly finished, level cut pile carpet. A plush is lower and more dense than a saxony. In a plush, each individual yarn end is less distinguishable than in a saxony.

A measure of the number of individual yarns twisted together to produce the finished carpet yarn. For example, a two-ply yarn means that each tuft consists of two yarns twisted together. Plied yarns must be heatset to prevent untwisting under traffic.

Polyester fiber
A synthetic fiber, usually produced with staple fiber and spun yarns, that is used in some carpet fiber.

Polymers are large chemical molecules from which synthetic fibers are made.

The first stage of nylon production:
A chemical reaction where small molecules combine to form much larger molecules.

Carpet that has been dyed in its tufted form. Post-dyed means the carpet rather than the yarn has been dyed.

Carpet that has been constructed with pre-dyed yarns

Printed carpet
Carpet having printed colored patterns. Printing methods include flatbed screen printing, rotary screen printing, and modern computer-programmed jet injection printing.

Producer-colored pigment
Color introduced into nylon fiber at the nylon manufacturing stage.

Random Sheared
A carpet texture created by lightly shearing either level loop or high-low loop so only some of the tufts are sheared. The sheared areas are less reflective than the unsheared loop which appear brighter and lighter in color. This creates a look similar to a cut and loop texture.

Red 40 Stain Scale
A standard comparison to rate degrees of Red Dye 40 staining from 10 (no staining) to 1 (severe staining).

The distance from a point in a design in a patterned carpet to a point where the identical pattern appears again, measured lengthwise and widthwise in the carpet. In matching the pattern, there will inevitably be some waste of carpet in order to obtain the best possible side match—whether it is a drop or set match pattern.

The ability of carpet to spring back to its original texture and thickness after being walked on or compressed by the weight of furniture.

Rows or Wires
Similar to stitches per inch (tufted carpet) in woven carpet, this is the number of pile yarn tufts per running inch lengthwise. Called rows in Axminster and wires in Wilton and Velvet carpet.

Sawtooth crimp
Also called zigzag crimp, this is a two-dimensional crimp that gives yarn cohesion, texture and bulk.

A cut pile carpet texture of plied yarns in dense configuration with surface yarns that are even across the face. The yarns in saxony are thicker and have more tip definition than in a plush.

Secondary Backing
Woven or nonwoven fabric reinforcement laminated to the back of the tufted carpet, usually with latex adhesive, to enhance dimensional stability, strength, stretch resistance, lay-flat, stiffness, and hand.

The edge of the carpet.

Set Match
Refers to a pattern in a carpet which continues straight across the installed carpet at right angles to the seams.

Apparent color shade difference between areas of the same carpet caused by normal wear and/or random difference in pile lay direction. It is a characteristic of cut pile carpet. It is not a defect.

Finishing process in carpet manufacturing to create a smooth carpet face. The shearing process can also be used to create texture as in random shearing.

Singles yarn
One yarn end of either continuous filament yarn or spun yarn. Singles yarn is most often plied (or twisted) with additional singles yarns to create a "two-ply," "three-ply" or "four-ply" yarn bundle.

Skein Dyed Yarn
Singles yarn that has been skein dyed. Yarn is wound in skeins and dyed in dye vats. This method yields small to mid-sized dye lots, but has custom color advantages.

An intermediate stage in the production of spun yarns from staple fiber. It is a large, soft, untwisted strand or rope of fibers produced by carding or pin drafting.

Smoke Chamber Test
Method that assesses smoke generating characteristics of a carpet sample due to pyrolysis and combustion by measuring the attenuation of a light beam by smoke accumulating in a closed chamber under controlled conditions.

Soil Hiding
The ability of a fiber to mask or "hide" the presence of soil.

Soil Resistance
The ability of a carpet fiber to resist dry soil and maintain its original appearance after intermittent or restorative cleanings. The amount of soil resistance can be determined by fluorine analysis.

The device (similar to a showerhead) which forms strands of filament as molten polymer is pumped through. It is at this stage that the fiber cross section, fiber size and the number of filaments in a yarn bundle (for continuous filament) are determined.

The conversion of staple fiber into spun yarn.

Spun Yarn
Yarn that is made up of short lengths of fiber, either synthetic staple or natural fiber.

Stain Resistance
The ability of a carpet fiber to resist the absorption of stain and maintain its original appearance. For carpets to resist stains, some manufacturers use a topical stain resist treatment that may be removed after hot water extraction.

Staple Fiber
Also called staple. Short lengths of fiber which have been chopped from continuous filament in lengths of 4" to 7 1/2". Staple fiber must be further processed (spun) into yarn before it can be tufted/woven into carpet. Nylon and polyester are examples of synthetic fibers available in staple form.

Static Control Test
A measurement of the amount of static discharge that occurs under specified conditions.

Static Shock
Buildup of electrostatic energy on a carpet and the subsequent discharge to a conductive ground such as a file cabinet. Various static control conductive systems are used in commercial carpet to dissipate static charge before it builds to the human sensitivity threshold, which is 3.5kV.

Stitches Per Inch (SPI)
Number of yarn tufts per running inch along the length of the carpet (as opposed to the gauge which is the number of stitches across the width of the carpet).

Stock Dyed
Colored spun yarn produced from fibers dyed in staple form.

Surface Area
The perimeter of an individual fiber filament or multiple filaments.

Surface Energy
Technical measure of the tendency of a surface—in this case, the carpet yarn—to repel molecules of another substance. Low surface energy refers to a repelling action.

Synthetic Fiber
Produced by man-made means, not available in nature in the same form.

Tensile Strength
The strength along the length of a fiber.

Visual and tactile surface characteristics of carpet pile, including such aesthetic and structural elements as high-low and cut and loop patterning, yarn twist, pile erectness or layover, harshness or softness to the touch, luster, and yarn dimensions.

Texture Retention
A carpet's ability to withstand crushing and matting. Although accelerated test methods do not directly compare with actual floor performance, they do give an indication of a carpet's ability to withstand crushing and matting.

Textured Loop
A woven or tufted carpet style having all tufts in a loop form, usually with two or three pile heights.

(See "Bulking.")

Tip Definition
Visible individual twisted cut yarn ends in a carpet surface. If, under heavy wear and pivoting, the tufts have been splayed open, the carpet is said to have lost its tip definition.

Tip Shearing
Shaving off tufted high loops in the finishing process to create a cut and uncut texture or pattern. Generally less definite pattern than random-sheared.

Titanium Dioxide (TiO2)
A compound that is used as the primary delusterant in fiber.

Total Weight
Weight (ounces) per square yard of the total carpet pile yarn, primary and secondary backings and coatings.

Continuous synthetic fiber filaments (without twist) collected in a loose rope-like form and held together by crimp. Tow is the form before fiber is cut into staple.

A cluster of yarns drawn through a fabric and projecting from the surface in the form of cut yarns or loops. (See also Cut pile, Cut and loop pile, Level loop pile, Loop pile and Multilevel loop pile.)

Tuft Bind
The force (usually measured in pounds) required to pull a tuft from the carpet backing. Also known as tuft lock. For loop pile, ASTM Method D1335 (tuft bind test) should result in a minimum 10-lb. average. For cut pile, ASTM Method D1335 (tuft bind test) should result in a minimum 5-lb. average.

Tufted Carpet
Carpet produced by a tufting machine instead of a loom.

A method of carpet manufacture in which surface yarns are sewn or "punched" through a primary backing material. The needles of the tufting machine form loops which are hooked by loopers on the underside of the backing material and which remain loops in level or textured loop carpet. Alternatively, the loops are tufted and cut with knives to create cut pile carpet. The tufted fabric is then coated with an adhesive to adhere a secondary back to provide durability and stability.

Turns Per Inch (TPI)
The number of times two or more yarns have been plied in an inch length. Also known as input ply twist.

Turns Per Tuft (TPT)
The number of twists in the pile yarn above the primary backing. A more accurate way of measuring relative twist level in cut pile carpets. Generally, the greater the turns per tuft, the better the performance.

A yarn term describing the number of turns per inch and direction of twist of either the singles or plies around their axes. Twist direction is either right or left handed, also called "Z" or "S" twist. Most carpet yarns have 3.5 to 6.0 TPI. The performance of a cut pile carpet is dependent on the twist in the pile yarn. Spun yarns need more twist than filament yarns for good performance. For moderate or heavy commercial use cut pile, it is suggested that continuous filament have a minimum of 4.50 TPI while spun yarns have a minimum ply twist of 4.75 TPI.

Most common yarn ply. Two single yarns are twisted together, then heatset to maintain their twisted configuration. Can be used in either cut or loop pile carpet.

A heavy back-coating of a polymer material, e.g., latex, to impart dimensional stability to a carpet.

A polymeric resin applied by the carpet mill in the finishing process. In the heat and curing chamber it reacts and creates a foam-like texture. This backing encapsulates the yarn for extra tuft bind with a cushion attached.

Velvet Carpet
Woven carpet made on a loom similar to a Wilton loom but lacking the jacquard mechanism. Velvet carpets are generally level loop, level cut/loop or plush, in solid or tweed colors.

Vettermann Drum Test
An instrument to test pile floor coverings to produce changes in appearance and color due to changes in surface structure by mechanical action. This accelerated test, primarily used in the US, provides a specific rating of the ability of the carpet to withstand crushing and matting.

Colloquial term for the synthetic polymer, polyvinyl chloride. Also called PVC. Used as a carpet back-coating for carpet tiles and 6' goods. Many walk-off mats have solid sheet vinyl backing.

A weaving term for yarns in woven fabrics and carpets which run in the machine direction (or lengthwise).

Irregular random shading or pile reversal in cut pile carpet.

The original method for manufacturing carpet. In the weaving process, backing yarns are woven into a durable fabric while simultaneously face yarns are looped over wires and interlocked in the woven back.

Yarns which run widthwise in woven carpet interlacing with various warp yarns.

A type of woven carpet and the loom used to manufacture it.

Parts of carpet weaving looms composed of thin metal rods or blades on which the pile tufts are formed. Round wires and cut wires are identical in shape. The cut wire has a small knife blade at the end and, as it is withdrawn, it cuts the yarn looped over it to form cut pile.

The original carpet fiber. Wool is noted for its versatility, excellent dyeability, luxurious feel and relatively high cost.

Woolen Spinning
Spinning method which produces bulky, hairy yarn, usually used for wool yarns. A series of cards, or large cylinders with comb-like teeth, straighten the fibers into a paralleled fiber webbing. This webbing is blended with other webbing, then spun into yarn.

Worsted Yarn
Made of long staple carpet fiber and combed to parallel the fiber and remove the extremely short fibers.

Woven Backing
A tufted carpet term for primary or secondary backing manufactured by the weaving process. Usually secondary backings are woven jute or woven polypropylene.

Woven Carpet
Carpet produced on a loom. Warp pile yarns intertwine with wires and backing yarns called warp yarns. These yarns are locked in with the weft yarns. Warp stuffer yarns are included to provide extra stability. Weaving is a slower, more expensive, labor-intensive fabrication method than tufting. Woven carpet is distinguished by intricate patterns and tailored, controlled textures.

Xenon Arc Lamp
The bulb used in the lightfastness fadeometer test. It contains a special gas, xenon, which produces an intense light that accelerates the color fading reaction. The fadeometer measures lightfastness in relative test hours.

A continuous strand of fibers used in tufting, weaving and bonding to form carpet and other fabrics. Carpet yarn is often plied and may be either spun staple or continuous filament.

Yarn count
A number used to describe the size of the yarn. Denier is used for BCF yarns, and cotton count for spun yarns.

Yarn Dyeing
Applying color to yarns before tufting or weaving it into carpet.

Yarn Ply
The number of single yarns ply-twisted together in a plied yarn

Yarn Size
The weight measure of the total bundle of filaments making up a yarn which indicate if the yarn is fine or coarse. Continuous filament yarns are sized by the denier or decitex system. Spun yarns are sized by the cotton count system. (See "Denier"or "Cotton count.")

Yarn Weight
Total amount of yarn used in the manufacturing of carpet. It is measured in ounces per square yard.

A loop pile carpet in which tufts are pulled from the backing resulting in long, lengthwise pulls (or run) out of the carpet.