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Commercial Carpet Specification

By Michael Hilton

Start with good performance. Carpet performance can be the result of:

  1. Specifications... was the correct carpet specified in relation to intended use of the carpet at its location?
  2. Color Selection... Was the proper carpet color selected to meet local soiling conditions, traffic conditions, intensity of sunlight?
  3. Installation... Was the quality of the carpet installation satisfactory?
  4. Maintenance... Was a regular carpet maintenance plan designed to serve the needs of the location?

Good performance begins with clear specifications which meet the needs of the functions to be performed and is completed with a maintenance plan to be put into effect immediately upon installation. The omission of any of these four items can seriously affect the perceived or actual performance of the carpet. Satisfactory performance of any carpet selected depends on the specification of proper construction, color and carpet fiber content. Maintenance will have a greater effect on the appearance of the carpet than any other single factor.

Carpet Specifications

Making an informed floor covering choice for commercial facilities, schools, and offices can be a difficult task. Budget concerns such as maintenance costs must be considered in addition to facility needs and the needs of the occupants.

One of the first decisions which should be made is the type of carpet fiber system preferred. All fiber systems have specific advantages. The two primary fiber systems used in commercial applications are olefin (polypropylene) and nylon.

Olefin has become one of the fastest growing fiber systems used in the manufacture of carpet. Olefin is one of the most inexpensive fiber systems available because of the capability that carpet producers have in extruding their own yarn. One of the limitations of olefin is the restrictive number of color choices. Limitations in color are a result of the dye method that must be used.

Most yarn systems such as nylon, polyester, wool, or cotton are dyed using a topical treatment of liquid dyes. These yarn systems contain tiny holes (dye sites) which allow the dyes to penetrate the yarn. Dye can be applied in a dye bath (beck) or sprayed-on topically. Olefin does not contain dye sites which allow dye to penetrate the fiber. Olefin is dyed using a solution-dye method. Solution dyeing occurs when the yarn is transformed from polymer chips to fiber. Polymer chips are added to a chamber and heated. Color chips are added during the heating process.

At the bottom of the chamber is a device called a spinneret which contains hundreds of tiny holes. As the solution melts and pours through these holes filaments of fiber are formed. It may take 1500 or more of these filaments to make up one-plyed yarn. As the color chips and polymer chips melt, the yarn is dyed through and through with color. Olefin's limitations in dyeing capabilities also can be considered an advantage.

Most carpet stains occur due to penetration of the dye sites. Olefin does not contain dye sites, making it almost impossible to stain. Another advantage of solution dyeing is the ability to withstand bleaches and oxidizing agents. Since the color is throughout the yarn, fading and bleaching cannot occur. Nylon can also be dyed using the solution-dye method but most nylon is dyed using the less expensive topical or beck dyeing method.

Nylon has been the fiber of choice for many years. Approximately 80% of the carpet manufactured in the United States is produced using nylon. It has very good resiliency, offers excellent color choices, and recent innovations in stain technology have improved nylons' ability to withstand stains. Solution-dyed nylon is even more stain resistant due to the dye method.

Carpet Construction

The construction of a prospective style of carpet has a major impact on the life expectancy and performance a carpet will provide. Carpet density is the major factor of construction that should be considered. Density is a combination of several factors. Gauge rate is the distance between tufts (loops) or needles in the widthwise direction.

# of needles per:

Gauge per Inch # across 12 ft width
5/32 6.4 922
1/8 8 1152
1/10 10 1440
5/64 12.8 1843

Stitch rate is the distance between tufts (loops) or the number of times the needle bar strikes in the lengthwise direction. Various styles may be measured differently. Stitches per inch is the most common unit of measurement but stitches per 6 inches may be found frequently.

Pile height is the length of the tuft (loop) from the base of the tuft (primary backing) to the tip of the tuft. Pile height is normally measured as a fraction of an inch or as a decimal equivalent.

3/16" = .188
1/4" = .250
5/16" = .313
3/8" = .375

Twist level has recently been identified as a major performance factor in many commercial cut-pile and residential cut-pile constructions. Twist level is measured in twists per inch. A close look at the tufts on a cut-pile product will reveal two bundles of yarn that have been plyed (twisted) together and heatset to "lock-in" the twist. Generally speaking, the more twists per inch, the better the performance.

Density can be defined as the amount of face yarn per unit area. There are several methods used for determining density. The primary method uses a simple empirical formula to quantify density.

Average Pile Density = 36 X Pile Yarn Weight / Pile Height (or pile thickness) in inches

Variations may occur due to differing methods of quantifying pile height. There are essentially 3 methods for determining pile height. Each method will deliver differing results.

In the first instance (pile height), a small ruler is inserted down to the backing to read the overall height of the tuft. This is not a precise method due to variations in results by various technicians. There may also be variations due to measurement timing (preshearing or post shearing).

The second method for determining pile height (pile thickness) is a much more precise method due to consistency of results. This is a much more complex method but it is the preferred method for determining pile height. This method involves the use of a compressometer, which measures thickness of materials under a slight load, between a platen and a circular foot. In using this method, the total thickness of the pile and backing material are quantified. The pile is then sheared and the backing thickness is calculated. These values are deducted and pile thickness is determined.

The third method, (tuft height) is also a laboratory technique which is reproducible. Ten tufts are sliced from the primary backing and inserted into a metal block. These "V" shaped tufts are then covered with a clear plate and measured using a precision scale. Problems can develop when product specifications are written using varying methods. A 30%-40% variance is possible on similarly manufactured goods when less precise methods are used.

Problems can develop when product specifications are written using varying methods. A 30%-40% variance is possible on similarly manufactured goods when less precise methods are used.

Carpet Color Selection

Few people realize the importance that carpet color selection has on carpet performance. Most people believe color should be selected based on aesthetic needs rather performance requirements. Carpet color can significantly reduce the cost of maintenance by reducing the appearance of soiling. Very light tones and very dark tones tend to reveal more soiling while middle-tones, multi-tones, patterned, tweed, and heathered tones can hide the effects of soiling. The geographic soil conditions should also be considered when carpet color is selected.

Traffic conditions may play a very large role in color selection. Carpet has the ability to trap tracked-in soils and restrict them to entryways. This can enable a specifier to alter carpet color with soil type and traffic load at each entryway.

Carpet Installation

Proper installation can directly affect carpet performance and increase the life expectancy of carpet. A large number of carpet installations are replaced due to installation failure rather than carpet failure. In many of these instances carpet replacement could have been prevented if proper installation guidelines had been followed. These guidelines are listed in Publication CRI-104 for commercial installations and CRI 105 for residential applications. A copy of these guidelines should be obtained and reviewed prior to carpet installation. They can be obtained through The Carpet and Rug Institute (706)-278-0232.

Prior to installation several points should be reviewed with the flooring contractor or architect/specifier.

  1. A rough sketch or diagram should be provided, detailing room measurements, openings, and unusual angles. Windows and doors should be noted along with direction of natural lighting sources.
  2. Be sure there is an understanding between the contractor and the building owner as to the location of all carpet seams that may be required prior to the beginning of the installation. If possible seams should be run perpendicular to the primary light source. In some installations the seams will peak when the carpet is stretched. This peaking may cast a shadow on the opposite side of the light source if the seams are run parallel to the light source. Keep in mind that no seam is completely invisible. Visibility will vary with type of carpet purchased. A bead of seam adhesive must be applied to all seam edges as well as all exposed edges. This will help in reducing seam separation and unraveling of the yarn.
    • If possible, seams should be kept to a minimum.
    • Seams should run the length of the area.
    • Main traffic should run along the seam rather than across the seam.
    • Seams should be away from areas subject to pivoting traffic.
    • Seams should not be perpendicular to doorway openings.
  3. The amount of carpet purchased should be reviewed prior to carpet purchase. Be aware that the amount of carpet purchased will likely be greater than the actual room dimensions due to standardized carpet widths. More seams may be added to reduce the amount of yardage but carpet must be run in the same direction throughout the installation due to color changes caused by reversing the pile direction. Less seams can be used in some installations by increasing the yardage which will increase waste. Seams must be used in rooms that are wider than standard carpet width. Most carpet styles are produced in either 12 ft, 13'6", or 15 ft widths.
  4. Carpet is usually glued directly to the floor in commercial applications and stretched over carpet padding in residential applications. Appropriate cushion should be used for the carpet specified. Should you have any questions concerning the type of cushion required contact the carpet manufacturer for their recommendation. Any carpet installed over pad must be stretched using a power stretcher. A knee kicker will not provide the necessary stretch needed for a good quality installation. The type of adhesive used to attach the carpet to the floor should be carefully considered. It is recommended that a low emitting adhesive be specified.
  5. Prior to removal of old carpet vacuum thoroughly to remove as much soil as possible. During removal this soil can become airborne which may temporarily cause a reduction in air quality. The subfloor should be vacuumed or cleaned thoroughly prior to installation of the new carpet. It should be understood, prior to removal of the old carpet, who is to be responsible for removal and disposal of the old carpet. There may be an additional charge for this service. In many areas of the country it is more cost effective to pay the installer to remove and discard the old carpet since landfill fees may equal or exceed the cost of the labor alone.
  6. When using any renovation materials it is recommended that the area should be ventilated for the first 48-72 hours. Certain renovation materials may require additional time for ventilation. If you or anyone in the area to be recarpeted is considered overly sensitive to chemicals, it is advisable that they leave the area during this initial 48-72 hour period. New carpet smell may be offensive to hypersensitive individuals. These odors should decay within the first 48-72 hours. The area to be carpeted should be free of obstructions. There may be an additional charge to move furniture or items considered fragile. Advance preparations should be made should any utilities need to be connected/ disconnected to insure a proper installation
  7. An installation date should be set and agreed upon. It is recommended that someone from the facility inspect the carpet prior to installation to insure proper style and color have been received.
  8. There may be leftovers or scrap materials left over from the installation. Notify the installers of your policy regarding these scraps. It is an excellent idea to save all the scraps from the installation. These scraps can be used as door mats to help reduce the amount of tracked in soil or they can be held in reserve should any area become stained or damaged. Sections of the carpet can be removed and portions of these scraps can be reinserted and seamed into these areas.
  9. Preparations should be made to insure that site environmental conditions should be between 65 degrees and 95 degrees and the relative humidity should be between 10% and 65%.
  10. All installation guidelines contained in CRI 104-CRI 105 should be followed for each installation.

About the Author
Michael Hilton was the original creator of Carpet Buyers Handbook. Having owned and operated a carpet wholesale company, Hilton has a vast knowledge about all-things carpet related as well as other types of flooring.

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THIS ARTICLE IS PROVIDED 'AS IS' WITH NO WARRANTY OF ANY KIND. THE AUTHOR, THE SITE OWNER AND ITS AFFILIATES ASSUME NO LIABILITY FOR ERRORS OR OMISSIONS CONTAINED THEREIN OR FOR ANY USE OF THE INFORMATION CONTAINED IN THIS DOCUMENT. The article is for informational purposes only and is not a substitute for professional advice.