Specifying the Right Carpet

Specifying the Right Carpet

Matching the Carpet to Your Needs

To choose the best carpet for your needs, first arm yourself with the right information.

Facility profile: The first step is to clearly define the specific requirements of the facility. Some things to consider include:

  • Type of facility and specific area receiving new carpet
  • How long the carpet will be used (life cycle)
  • Types of dirt that may be tracked into the facility
  • Whether the area is a remodeled or a new installation
  • Whether access to the subfloor is required
  • Whether there is modular furniture in the space

Location profile: To maximize performance, you first must also determine where the carpet is going to go in the facility.

Below are some location-specific questions to ask:

  • On a typical day, will there be spills and stains or dirt tracked into the building? If so, what type of spills? Food stains? Coffee or chemical spills?
  • What will the frequency of spills be? Excessive? Occasional?
  • What about moisture? Do you need a moisture permeable or impermeable backing?
  • Is there exposure to harsh chemicals, intense sunlight, or atmospheric contaminants (such as nitrous oxides or ozone)?
  • Will there be lots of foot traffic? Wheelchairs? Supply carts?

The Right Carpet for Any Environment

Today’s carpet offers you a wide variety of choices in style, fiber composition, and color, whether you are specifying broadloom or tile for a corporate office, school, and public space or purchasing an area rug for a boutique hotel. New technology can produce multilevel loop and cut-loop patterns with diamond, bow, pin dot, fleur-de-lis, or other designs.

Carpet can give personality to a workplace, ranging from formal to bold. In hospitality settings, it can provide directional clues to move people to the registration areas or elevators. In healthcare settings, carpet can be soothing and emotionally healing. It can quiet a computer lab in schools. In retail, carpet can compliment merchandise displays.

For more information, download the CRI Model Specification for Commercial Carpet (1 MB).

To match the best carpet to the proper end-use, you should consider:

  • Carpet Construction
  • Dyeing and Color Selection
  • Size Options
  • Quality and Performance Requirements
  • Insulation
  • Sound Absorption
  • Cushion

ANCHOR – Carpet and Rug Construction

Understanding Carpet Construction

The look and performance of a particular carpet are determined by its construction, which may be loop, cut, or combinations of the two. In corridors, lobbies, offices, classrooms, hotel rooms, patient care facilities, and other public areas, loop styles with low dense construction tend to retain their appearance and resiliency and generally provide a better surface for the rolling traffic of wheelchairs or food carts. Cut pile or cut and loop pile carpets are optimal for administration areas, libraries, individual offices, and boardrooms.

Various types of high-performance backing systems have additional advantages, including higher tuft binds, added stability, imperviousness to moisture, and resistance to edge raveling. Consideration should be given to the functional needs of a particular area.

Understanding carpet construction assists in specifying elements that will provide the best performance in a particular location. Commercial carpet is primarily manufactured by tufting or weaving. Each process will produce quality floor coverings, but tufted carpet accounts for 95 percent of all carpet construction. Both tufting and woven manufacturing are efficient and employ advanced technology to provide capabilities for a myriad of patterns and styles.

Tufted

Tufted: Tufting is the process of creating textiles, especially carpet, on specialized multi-needle sewing machines. Several hundred needles stitch hundreds of rows of pile yarn tufts through a backing fabric called the primary backing. The needles push yarn through a primary backing fabric, where a loop holds the yarn in place to form a tuft as the needle is removed. The yarn is caught by loopers and held in place for loop-pile carpet or cut by blades for cut-pile carpet. Next, secondary backings of various types are applied to render a variety of performance properties.

Here are some key steps in the tufting process:

  • Yarn comes from cones on creel racks (or from big spools called beams) into the machine.
  • The primary backing feeds into the machine.
  • Yarn and primary backing come together in the machine.
  • Yarn is fed through needles on a needlebar of a tufting machine. Needles repeatedly penetrate or tuft into the primary backing.
  • The tufted carpet is mended and inspected.
  • Carpet is rolled onto large rolls for the next step (dyeing or backing).
Woven

Woven: Woven carpet is created on looms by simultaneously interlacing face yarns and backing yarns into a complete product, thereby eliminating the need for a secondary backing. A small amount of latex-back coating is usually applied for bulk. Principal variations of woven carpet include velvet, Wilton, and Axminster.

Understanding Carpet Fibers

To get the best performance and most enjoyment out of your carpet it’s essential to select a carpet fiber that fits your needs. The majority of the carpet produced in the United States contains one of five primary pile fibers: nylon, polyester, polypropylene (olefin), triexta, and wool. Synthetic fibers represent the vast majority of the fiber used to manufacture carpet in the U.S. Each fiber type offers somewhat different attributes of durability, abrasion resistance, texture retention, stain and soil resistance, colorfastness, ease of cleaning, and color clarity. Manufacturers, retailers, specifiers, and designers are valuable resources in helping you determine the most appropriate fiber and carpet construction for your needs.

Facts on Backings

All carpet has some type of backing system or chemistry that helps keep the tufts in place. Backing systems are made from a variety of materials and may also come with various kinds of protective treatments (such as anti-microbial or anti-stain) or beneficial properties (such as anti-static).

The methods and chemicals used depend upon the performance requirements of the backing and the carpet. These decisions will be based upon the specifier’s performance considerations and the manufacturer’s recommendations. Performance considerations are especially important for demanding environments. It’s important that the specifier identify the highest priority needs for how the carpet will perform, whether that is wear and tear, moisture-resistance, or heavy foot traffic. The manufacturers’ end use recommendations help determine which product will meet the established performance expectations.

Carpet backing systems generally comprise a primary backing and a chemical adhesive. Frequently, a secondary backing is included. In the most common system, the yarn is secured into the primary backing by synthetic latex, and a secondary backing (or cushion) is attached with a bonding agent or adhesive to provide further pile-yarn stability and to add dimensional stability to the carpet structure.

Understanding Dyeing

Dyeing is the process of coloring fiber, yarn or carpet with dyestuff. Coloration in carpet can be achieved at three possible times in the manufacturing process: during fiber development, before the carpet is tufted or before the secondary backing is applied.

The end use of the product will determine the type of dye method. Manufacturers can determine the most appropriate construction, dye method, and backing to meet the performance requirements. For example, a specifier may be concerned about fading in a setting with large windows, so the manufacturer would recommend a solution-dyed product with superior colorfastness. If the specifier wants a wide variety of bright colors, the manufacturer might recommend yarn dyeing or space dyeing.

Different Dyeing Methods

Pre-dyeing of yarn includes both solution dyeing and yarn dyeing.

  • Solution dyed: Synthetic yarn that is extruded and the filaments are impregnated with pigment. Known for outstanding colorfastness.
  • Yarn dyed: Yarn is dyed before carpet is manufactured. Yarn dyeing includes multicolor space dyeing and solid color yarn or skein dyeing.

Post-dyeing of carpet methods include: beck dyeing, printing and continuous dyeing.

  • Beck dyeing or piece dyeing: With these methods, carpet is dyed “in a piece” using a large beck, or vat, of dyestuffs and water. This takes place after tufting but before other finishing processes.
  • Printing: Printing involves the application of colored dyestuffs using screens, rollers or inkjets onto the face of the carpet.
  • Continuous dyeing: Continuous dyeing involves the application of dyestuffs as the carpet moves in open width under the dye applicator. The process is called “continuous” because it can be used to dye an unlimited quantity of 12-foot wide carpets, sewn end to end. (This is most often used in residential carpet.)

Using Color and Pattern

Floor coverings are one of the dominant fashion statements for an indoor setting. Colors and patterns in a carpet can create a distinctive atmosphere, serve a practical purpose, or send a message.

Within a facility, bright colors with contrasting highlights can differentiate department or team areas. An accent color on the floor can establish a break between the floor and the wall or stairway, and a printed or tufted pattern carpet can reinforce a corporate identity.

Color selection of carpet is as diverse as the imagination can provide. Quiet colors such as neutral earth colors or the blues of sky and water are chosen for a soothing effect or a corporate look. Warmer colors, reds, maize, and shades of orange are used for creating a mood of energy and vitality. Mid-range colors and multicolor blends are best for hiding soil near entrances. Many carpet manufacturers will also produce custom colors and constructions to meet individual specifications for design coordination.

So you decide what you want your carpet to do and how you want it to fit in with the overall look and feel of your environment. There will surely be many good options from which to choose.

A Size to Suit Every Purpose

Building owners and facility managers can select between tufted or woven products in various widths and sizes based on styling preference, budget considerations, backing performance needs (e.g. moisture impermeability) and facility requirements (e.g. installation and floor access). In the commercial market, the size options include broadloom, modular carpet tile, and 6-foot carpet.

Broadloom Carpet

For the majority of commercial installations, broadloom carpet is specified to produce fewer seams, ease installation, and obtain certain moisture benefits. Broadloom carpet can be 12 foot, 13’6 feet, or 15 feet in width. Broadloom carpet can offer large pattern repeats and the ability to pattern match. For many years, commercial installations used broadloom carpet almost exclusively.

Six-Foot Carpet

Six-foot-wide carpet has a continuing history of popularity and is available in many designs with a variety of backing systems. This narrow carpet roll is often a benefit in high-rise buildings, where transporting a 12-foot roll is difficult or expensive. The narrow width may also provide cost savings where corridors or other narrow spaces exist. However, careful planning is needed to avoid additional seams.

Carpet Tile Construction and Installation

The frequently changing configurations of open plan systems in offices and institutional settings have spurred advanced technologies in carpet tile. When a facility demands the accommodation of flat electronic wiring, ease of removal, and installation and/or flexibility in design, modular tile may be the best choice. Where traffic paths or soiling occur, rotating tiles is sometimes a better alternative than a complete replacement.

There are also advances in installation techniques. Modular tiles are being installed with standard adhesives, releasable adhesives, mill-applied peel-and-stick adhesives, and innovative after-market adhesive strips. In many facilities, modular tile installation is easier and faster than traditional carpet installation. A facility’s divider panels and office furniture do not have to be removed from the area, but simply lifted with a “jack” system and the tiles are installed underneath. An entire office area can often be re-carpeted in one overnight shift, rather than disrupting an office for days. The reduced disruption of business may make up the difference in the extra cost of the product and installation.

Modular tile backings include those made with polyvinyl chloride (PVC), polyethylene, polyester, non-wovens, and polyurethane cushion. The “hard backs” (i.e. PVC, polyester. and polyethylene) offer dimensional stability, seam and edge integrity for easy pattern matching.

Tile backing systems can also offer moisture barriers from the base of the pile yarn to the floor, preventing spills from penetrating and seeping down to the subfloor. In modular tiles, as well as with broadloom, a moisture barrier may be valuable in humid areas or healthcare environments where spills are inevitable and cleaning is frequent. The moisture barrier of the carpet itself and of the sealing technique for the seams may lessen the potential for bacterial growth and provide lower long-term maintenance costs.

Accommodating Electronic Cables

Manufacturers offer low-profile systems which use as little as 2 ½  inches of the vertical space – a value when the ceiling height is only eight feet. Modular carpet with a cushion backing is often chosen for noise reduction and increased underfoot comfort. Companies offer differing size configurations of raised flooring and depths to accommodate extensive wiring, and even duct work for heat and air systems.

Determining Durability

Carpet performance is associated with many things, and it’s important for a specifier to understand how all the individual elements work. For example, the construction method should be appropriate for the end use and the traffic requirements; the yarn size needs to correlate with the gauge; the backing systems should be appropriate with the desired performance; and the dye technique has to be consistent with the end use.

The most common trap is relying on only one single construction factor to determine if a product will meet specifications. Therefore, while pile yarn density is important, so is the gauge, the yarn size and many other construction parameters that can be determined by individual manufacturers. That’s why it’s so important for specifiers and end users to explain how they want the product to perform and allow the manufacturers to make the construction decisions to meet the identified needs.

Carpet performance is associated, in part, with pile yarn density – the amount of pile yarn in a given volume of carpet face. For a given carpet weight, lower pile height and higher pile yarn density will yield the most performance for the money.

Density is also influenced by the number of tufts per inch when counting across a width of carpet. For example, a 1/8 gauge carpet has eight tuft rows per inch of width and a 1/10 gauge carpet has 10 rows per inch of width. Extra heavy traffic conditions require a density of 5,000 or more.

Appearance is an aesthetic choice, while texture retention is a performance issue. However, the two areas are closely related. Heavy foot traffic and soil can discolor carpet and should influence design decisions. Mid-tone colors and colors that blend with the general shade of local soil are the best to use in high traffic areas, especially near entrances. Manufacturers often recommend “walk-off” carpet systems for entryways. Walk-off carpet is designed to clean shoes of dirt and moisture and protect entrances from excess soiling. In addition, walk-off carpet systems increase foot safety and reduce slip and fall accidents. Eight feet of walk-off carpet is frequently considered to be optimal to protect interior carpet installations as well as enhance user safety and comfort.

Understanding Thermal Values (R-Values) of Carpet and Cushion

An industry-sponsored study of the thermal characteristics of carpet – with and without cushion – conducted by the Georgia Institute of Technology School of Textile Engineering, concluded that the total R-value (thermal value) is more dependent on the total thickness of the carpet than on the type fiber content.

When the carpet R-value is not available, the study suggested multiplying the total carpet thickness measured in inches by a factor of 2.6 to approximate the carpet’s R-value. The study also found that R-values are additive for any combination of materials. For example, a combination of carpet with an R-value of 1.3 and a prime polyurethane cushion with an R-value of 1.6 will yield an overall R-value of 2.9.

Download Understanding Thermal Values (R-Values) of Carpet and Cushion (47 KB), with more detailed R-value information that was taken from the study conducted by the Georgia Institute of Technology School of Textile Engineering.

Specifying for Acoustics

Carpet is an outstanding sound absorptive material. No other acoustical material performs the dual role of a floor covering and a versatile acoustical aid. When properly selected, carpet absorbs airborne noise as efficiently as many specialized acoustical materials. However, it is important to understand the acoustical values of particular carpet constructions and the combinations of specific carpet cushions. This information will assist you in selecting the appropriate combination for a specific purpose.

Sound Absorption

Sound absorption coefficients, the fraction of incident sound energy that is absorbed by a material, usually vary strongly with frequency. A noise reduction coefficient (NRC) is used to grade the effectiveness of a material employed for sound control.

Small samples can be measured by the impedance tube method, while larger specimens can be measured by the reverberation room method. Reverberation room coefficients are usually provided as a single number, NRC. This number is the average of the coefficients at 250, 500, 1000, and 2000 Hz (from low- to high-pitched sounds).

Sound Transmission

Transmission through walls, floors and other barriers is much greater for low-frequency sounds than for high-frequency sounds. Sound transmission is measured between two reverberation rooms for at least 16 standard frequency bands.

For convenience in comparison of different constructions, the sound transmission class (STC) rating condenses sound transmission information into a single number according to ASTM E-413. STC is fairly accurate for human speech; however, for low-frequency sound, such as a motor, fan, or even music with strong bass, the perceived sound may be greater than that indicated by STC.

Match Cushion to Carpet for Best Results

Selecting the right backing system – including whether some type of cushion is attached – is critical. While cushion can provide resilience, acoustical/thermal insulation properties, and comfort underfoot, the majority of commercial broadloom carpet today is direct-glued to the floor without a cushion. The carpet product and backing should be selected according to the traffic patterns of the area and the manufacturer’s requirements for thickness and density. Carpet tile is generally designed to function without the need of additional cushion.

There are three main types of carpet cushion in commercial broadloom applications: Fiber, Rubber, and Polyurethane foam.

  • Fiber cushion is made of rubberized hair, rubberized jute, synthetic fibers, or recycled textile fiber.
  • Rubber cushion consists of flat rubber, textured flat rubber, rippled waffle (Class I only), or reinforced rubber.
  • Polyurethane foam cushion is made of grafted prime polyurethane, densified polyurethane, bonded polyurethane, or mechanically-frothed polyurethane.

The three classes of commercial carpet cushion applications are Class I, Class II, and Class III.

  • Class I (moderate traffic) — Typically, this class includes executive, administrative or private offices in office buildings, banks, schools, and healthcare facilities.
  • Class II (heavy traffic) — Generally, this class includes clerical areas, corridors, patient’s rooms, lounges, classrooms, and public areas in healthcare facilities, libraries, museums, hotels, motels, and schools.
  • Class III (extra heavy traffic) — This class includes cafeterias, nurses’ stations, public and ticketing areas, and lobbies in office buildings, airports, and healthcare facilities.