Advanced Carpet Backing Technology Receives High Marks at UC Merced

Sept. 1, 2007

By Kenn Busch

In a multiple-choice market, only the right answer counts.

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Sidebar: A Primer: Making Your Carpet Specs Count

If you've ever designed spaces or specified materials for a university, you know that few clients are more demanding. Durability, longevity, environmental responsibility and above all, value, are thoroughly scrutinized before any building or build-out can begin. And if that project happens to be in California, you also know that no state has higher standards for sustainable materials in building design.

 As the latest addition to the University of California system, UC Merced is at the forefront of responsible design and environmental sustainability, from the floor up-literally. This is why the carpet and high-performance polyurethane backing system were carefully selected by the university for their high-performance and environmental advantages.

While standard backings are economical and perform adequately in low-traffic areas, they can compromise intricate patterns, won't stand up to high traffic, and can break down during the cleaning process.

Specifying high-performance backings helps the carpet endure higher traffic. They have different characteristics that are specified based on end-use requirements, such as performance, high comfort, noise reduction, rolling traffic, moisture barrier properties and possibly recycled content. Polyurethane technology for commercial carpeting creates a distinct molecular structure-forming a polymeric bond between the primary and secondary backing. The result is a unified composite material that helps improve the performance of carpet.

The success of the flooring at UC Merced starts with the carpet backing, which was made with an advanced polyurethane technology available by request from all major carpet manufacturers.

In September 2005, UC Merced opened as the 10th campus of the renowned University of California system and the first American research university to be built in the 21st century. The school, which offers a range of undergraduate and graduate programs, is projected to grow to a 25,000-student enrollment at full build-out by the year 2030.

Library spaces require flooring that offers sound absorption, comfort and durability-but still with a sophisticated style.

One of the first buildings to be completed in the extensive design and construction process was the Kolligian Library. This building not only houses traditional library services, but also includes administrative offices, conference rooms, student government, student services, a book store and even a coffee shop. All of these spaces require flooring that offers sound absorption, comfort and durability-without sacrificing sophistication and style.

"To meet our specific needs, the carpet backing system was very important," says Min Jiang, UC Merced project director. "We explored several options, but in the end went with polyurethane backing primarily for its environmental, sound absorption and cushioning qualities. Above all, the university is proud to announce that we are PVC-free in carpet."

The UC Merced campus utilizes principles of sustainability in building design, construction and operation, and serves as a model for development in the San Joaquin Valley. They have even formed an Environmental Stewardship Program that is responsible for the development of specific goals and policies to set the standards for sustainable use of energy and other scarce resources.

The type of flooring used throughout the campus is contributing to the university's environmental goals. All carpet is required to be PVC-free and made of recycled content. In the Kolligian Library, both the broadloom and cut-pile carpet meet these environmental requirements.

Because the Kolligian Library is a busy campus hub, the flooring and finish choices had to help balance the noise of student activity with the need for quiet study and reflection. The specification of a high-performance, cushioned polyurethane carpet backing plays a key role in keeping the space's acoustics under control.

An effective noise reducer, cushioned carpet backing made with polyurethane technology minimizes the sound of foot traffic, absorbs airborne sound and reduces sound transmission to nearby rooms. Made of high-density polyurethane, the cushioned backing is also designed to increase comfort underfoot. It helps reduce heel-strike force and leg muscle response-two prime causes of standing and walking fatigue. (This is a key concern for facilities like the Kolligian Library, where staff members are on their feet for long periods of time).

In addition to offering comfort underfoot, the library's carpet needed to retain its appearance and performance for years to come-a key issue in assessing the environmental impact of building materials on UC campuses, as well as in justifying the expenditure. University Librarian Bruce Miller was so adamant about these requirements that he put the carpet through some of his own rigorous testing during the specification process. He purposefully spilled coffee on a carpet sample and found that even after a quick cleanup with paper towels, there was no permanent staining. 

"We do not have the funds with which to replace carpet on a regular basis," says Miller. "That's why carpet in the library must function well and look good for a very long time. And so far, normal cleaning has kept the place looking good."

And it will stay looking good for longer, according to a study conducted by Brigham Young University. The normal life expectancy for carpet at BYU is five to 10 years. The proposed life expectancy with a properly specified backing system using polyurethane technology is now eight to 15 years-an increase of 64 percent, with a yearly savings estimated to be over $250,000.

Resistance to stains and odors from spills is also critical to the longevity and newness retention of commercial carpet. With conventional backing, removing the spill on the surface is frequently ineffective because residual liquid can continue to wick back up from below and reappear on the carpet pile over and over again. This can cause serious appearance problems, sometimes more pronounced than the initial stain. By design, the polyurethane backing at the Kolligian Library forms a functional barrier that stops liquid and dirt from penetrating to the subfloor, thereby reducing the occurrence of wick-back staining and odors due to spills. Plus, it allows for aggressive cleaning programs, including hot-water extraction.

"The primary problem I have encountered with carpet at other campuses is that it snags, runs and frays at room entrances, on stairs and at seams," adds Miller. "Time will tell about the performance here at room boundaries and seams."

Fortunately, the carpet backing system at the Kolligian Library is designed to handle such punishing conditions over the long term.

Polyurethane's strong adhesion properties allow the carpet yarn to maximize the tuft bind for the life of the carpet. This helps minimize edge ravel, disfiguring snags and pulls, and pilling and fuzzing. It also reduces the likelihood of delamination-a common problem in settings with rolling traffic. To further protect the appearance of the carpet, polyurethane allows the carpet and cushioned backing to absorb the pounding wear of foot traffic and support the heavy weight of furniture without bottoming out. The library's backing system is designed to reduce pile crushing and matting over time, which is especially effective in high-traffic areas like entryways and hallways. Ultimately, improved durability and performance provided by the backing extend the carpet's life and the library's budget. .

Ultimately, improved durability and performance provided by the backing extend the carpet's life and the library's budget.

By carefully specifying the right carpet and backing system for their needs, UC Merced now has flooring that can withstand the intense traffic and abuse of a university, and still offer sophisticated style and sustainability. Polyurethane backing helps maintain the appearance of the carpet for years to come.

In the end, students who come to the Kolligian Library may not even take notice of the carpet. But that's the beauty of a high-performance carpet and backing system-carpet usually only gets noticed when it fails to do its job.

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A Primer: Making Your Carpet Specs Count

Backing is the foundation of carpet, just as steel girders are the foundation of a building. It supports the carpet and can protect its beauty and overall functionality for years after the installation. That's why specifying backing is as important as selecting the color, fiber and pattern of your carpet: It's an essential part of the commercial carpet selection process. The backings you select can significantly boost the carpet's physical properties, ergonomics, acoustics, moisture resistance, breathability, appearance retention and sustainability.

Building a Backing System
The carpet's stability starts with the primary backing, which is the woven or non-woven foundation into which the face yarn is inserted by the tufting needles. During the final "finishing" stage of the carpet's production, a secondary backing is attached to the primary backing with a heat-cured adhesive. The primary backing provides additional stability and locks the carpet's face fibers in place.

Depending on the intended application for the finished carpet, you can choose from several types of backing systems. Today's backings have been designed to meet virtually every need:

  • Bow and skew reduction;
  • Prevention of liquid penetrating the subfloor;
  • Softness that allows for easy installation and minimal damage from scratching; and,
  • Recycled content.

When working with a carpet manufacturing representative, always ask what backing options are available. Many manufacturers offer a variety of backings, other than just the ones shown in the architect folder. They often showcase these in a separate folder to aid in the selection process.

Primary Backing Options
Primary backings of the past were mostly made from jute, which was prone to separating at the seams, rotting, mildewing and shrinking. Today, most primary backings are made from woven polypropylene. There are also a number of specialty primary backings such as those used for beck-dyed loop-pile carpet; composite backings suitable for high-end, patterned commercial carpet; and spunbonded polyester non-woven backings.

Benefits of High-Performance Secondary Backing
When compared to other carpet backing systems, polyurethane is the high-performance backing of choice for commercial settings, due to a wide range of benefits. Polyurethane backings offer superior tuft bind, moisture resistance, and reduced likelihood of delamination and edge raveling. The polymeric bond between the primary and secondary backings creates a unified composite material that provides consistent performance over the life of the carpet, even under intensive use situations. The polyurethane backing's unique molecular structure supports the heavy weight of furniture and absorbs the pounding motion of foot traffic, thus reducing crushing and matting over time. Plus, it adheres naturally to nylon fibers, which minimizes edge ravel and disfiguring snags or pulls.

Benefits of Polyurethane Backings
Polyurethane backings with an attached cushion not only extend the beauty of the carpet, but also offer improved ergonomics, energy savings, roller mobility and acoustics. Polyurethane backing made with a high-density cushion reduces standing and walking fatigue, as well as excessive noise, which directly impacts worker and occupancy comfort levels.

Non-cushioned polyurethane backings are ideal for many broadloom carpet applications. These backings enhance durability, ease of maintenance and longevity in schools, hospitals, banks, casinos-anywhere you find extreme wear and tear.

Functional Liquid Barrier
No matter what the application, always consider the long-term performance of the floor. That's why it's important to understand the value of selecting the right backing to help boost the performance and life of the carpet. To further improve the carpet's appearance and to resist wear and tear, select a polyurethane backing with a functional liquid barrier. The polymer within these carpet backings contains hydrophobic segments that impede liquid and dirt penetration to the subfloor. This minimizes the risk of odors due to liquid spills penetrating beneath the carpet and reduces wick-back staining. Plus it allows for aggressive maintenance like hot-water extraction. The result is carpet that looks better and lasts longer.

Polyurethane carpet backings also meet demands that go beyond aesthetics and performance. The unique chemistry of polyurethane carpet backings offers excellent indoor air quality with respect to detectable volatile organic compounds. Plus, it's designed to comply with CRI Green Label standards and can often be reclaimed and recycled when used with recyclable carpet. Installation of carpet with polyurethane backing may also qualify for credit under the LEED (Leadership in Energy and Environmental Design) Green Building Rating SystemTM.

Installation and Maintenance
A final consideration in your carpet and backing selection is installation. Carpet with polyurethane backing provides an efficient, one-step installation alternative, requiring up to 40 percent less labor than the double stick method. Polyurethane is both soft and tough and is able to maintain flexibility over a wide range of temperature and site conditions. It is also more easily repaired and is breathable, which aids in drying and curing of adhesives. In addition, it facilitates seaming and pattern match in the installation process. Always refer to the CRI 104 Installation Guidelines provided by the Carpet and Rug Institute for proper installation. And choose trained installers who will follow these guidelines as well as those of the manufacturer. To maintain the carpet once it's installed, consider walk-off mats, chair pads and routine cleaning programs.

Ultimately, the performance of your carpet is determined by the materials used and the method of assembly utilized. All the materials and details in the construction of the carpet, including color, pattern, yarn type, dying method, style, topical treatment and backing work together to create a quality product. Each variable must be considered since it will impact the overall performance and aesthetics of your carpet. Selecting a high quality carpet backing system means you can expect more from your carpet-from great design and performance to long-lasting wear and comfort.

End-Uses for Polyurethane Backings
All these attributes make polyurethane backings the ideal solution for a variety of applications. For example, its superior ergonomics and sound absorption work well in corporate settings, especially in noisy open office plans. Polyurethane also addresses the unique issues concerning healthcare facilities such as mobility, noise and spills. In educational environments, polyurethane improves acoustics and stands up to aggressive wear and tear, which can extend tight budgets. Polyurethane is also a popular choice in retail and hospitality settings, where heavy traffic and appearance retention are key factors.

The Universal Advantages of Polyurethane Carpet Backing 

  • Appearance retention
    Carpet with a polyurethane cushion looks better as it lasts longer, absorbing the pounding motion of foot traffic and the heavy weight of furniture without bottoming out. 
  • Functional liquid barrier
    Polyurethane backing resists stains and odors from liquid spills. With conventional backing, removing the spill on the surface is frequently ineffective because residual liquid can continue to wick back and reappear on the carpet pile over and over again, sometimes more pronounced than the initial stain.
  • Durability and budget
    Polyurethane's adhesion to carpet yarn maximizes the bundle wrap around individual tufts for the life of the carpet, minimizing edge ravel and disfiguring snags and pulls.
  • Sound absorption
    Excessive noise is a common complaint from hotel guests. Cushioned polyurethane carpet backing serves as an effective noise reducer by minimizing the sound of foot traffic, absorbing airborne noise and reducing sound transmission to floors below.



Learning Objectives:

Interiors & Sources' Continuing Education Series articles allow design practitioners to earn continuing education unit credits through the pages of the magazine. Use the following learning objectives to focus your study while reading this issue's article.

After reading this article, you should be able to:

  • Explain the difference between high-performance and standard carpet backing
  • Identify three performance and maintenance benefits of polyurethane technology for carpet backing
  • Determine how long carpet with polyurethane backings last

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