Floor Covering Archives | Carpets Wall to Wall

Carpet Cushion Tests Methods for Evaluating Carpet Pad

Carpet cushion tests methods are used for the evaluation of carpet pad (cushion). The industry has developed a number of carpet cushion tests methods for evaluating carpet cushion. These evaluations have resulted in a better carpet pad being offered to the consumer.

Many wall to wall carpets will experience premature failure as a result of cushion (pad) failure. Unfortunately a large percent of those in the carpet industry that call themselves “professional” do not recognize when it is the cushion that has failed and not the carpet. When it is believed that a pad has failed there are carpet cushion tests methods for on-site evaluation. Expert-professional inspectors such as the Oregon based Weinheimer Group will be able to determine if it is the carpet or the pad that has failed.

Manufacturing Carpet Cushion Tests Methods

Evaluation of Cushion Density of Foam Style Cushion

To determine density, a one cubic foot (12″ x 12″ x 12″) of foam is weighed. The weight of this cubic foot is reported as (x) pounds per cubic foot. This is a reasonably accurate test that is reporting the material’s actual substance, in this case the substance being the density. The higher the density the better the support characteristics of the product.

Cushion Thickness

With cushion, thickness does not mean density. Thickness is the measurement of the product from one side to the other as the product has been manufactured for use. Thickness is shown as a fraction of an inch or in its decimal equivalent, i.e., 5/32″, 3/8″, 7/16″, 1/2″, 9/16″.

CFD (Compression Force Deflection)

A measure of the load bearing ability of a foam. It is the force exerted against a flat compression foot larger than the specimen to be tested. The value can be expressed at 25%, 40%, 50% and/or 65% compression (ASTM D3574). Note: Previously called “CLD” (Compression Load Deflection)

IFD (Indentation Force Deflection)

A measure of the load bearing capacity of flexible polyurethane foam. IFD is generally measured as the force (in pounds) required to compress a 50 square inch circular indentor foot into a four inch thick sample, typically 15 inches square or larger, to a stated percentage of the sample’s initial height. Common IFD values are generated at 25 and 65 percent of initial height. (ASTM D3574.) Note: Previously called “ILD” (Indentation Load Deflection).

Walk-on Testing

This is a standardized testing procedure that can be used by any segment of the industry from carpet manufacturers and cushion producers to distributors and retailers. This test is used to evaluate installed residential carpet system performance. While this test can be used to evaluate different styles of carpet over a particular control system it can also be used to compare the effects of different types of carpet cushion on the composite floorcovering system. The complete protocol for this test is available through the Polyurethane Foam Association.

Onsite Carpet Cushion Tests Methods (Field Evaluation)

Discoloration

The gradual yellowing of foam due to a photochemical reaction. It is faster in sunlight than in artificial light, although it occurs in both. Fresh foam may discolor in the center of the block as a result of thermal or chemical events. Discoloration does not affect the physical properties of the foam.

Hard Spots – Resin

Spots that are hard like a marble are generally from the resin used in the bonding process. A spot that is hard enough to be felt is generally considered a defect. The proper correction is to remove the spot. A pad should not require replacement unless the spots are excessive.

Hard Spots – Skin

These are shiny, narrow, hard pieces that come from the outside of some foam buns. An inexpensive pad will likely contain more skin than a better variety. Skin spots are a characteristic of many bonded urethane cushions and it is common for manufacturers not to consider them a defect unless they are large enough and hard enough to cause discomfort when walking in bare foot.

Mildew Problems

Slow seepage or flood that goes undetected or uncured for several days may result in mildew. Fiber pads suffer this problem. Rubber & foam are impervious, but they must still be removed because they retain water and the carpet backings are also liable to suffer from mildew.

Oxidation Problems

Rubber & foam pads depend on the sealing off of floor & carpet surfaces to prevent undue oxidation. Areas with bad air pollution (NO2, O3) intensify problems. Fiber pads are impervious to this problem.

Thickness

A cushion that is too thick will protrude above the tack strip and will not allow for a good grip of the carpet against the pins, and may also cause a valley to appear along the edges which can lead to excessive restretch problems.

CRI 104 states that cushion thickness should not exceed 3/8 inch (9.5 mm) for commercial installations, and CRI 105 states that cushion thickness should not exceed 7/16 inch (11 mm) for residential installations. Whenever performing a claim where cushion failure or specification is in question, a sample of the cushion needs to be selected.

CRI Carpet Installations Standards 2011 states, Separate Cushion Selection: It is required that the cushion conform to carpet manufacturer recommendations for the specific product being installed. Failure to follow these recommendations for cushion may void manufacturer warranties. These recommendations may differ, depending on the style and construction of specific carpet. Cushion thickness for commercial carpet installations should not exceed ⅜ inch (10 mm.)

Weight or Density Problems

Rubber pads over 75 oz., or bonded urethane and foam pads of greater than 7/16″, especially less than 5.5 lb. density, while adding comfort to some customers, also lessen the life of the carpet by intensifying problems of delamination.

CRI Green Label Cushion Testing Program uses a variety of carpet cushion tests methods to evaluate carpet pad.
Carpet Cushion Consumer Guidelines, Carpet Cushion Council

Carpet Pad Manufacturing and Cushion Styles

By Terry Weinheimer 1 Comment

Carpet Pad Manufacturing

The carpet pad manufacturing industry produces a broad variety of carpet cushion styles. Carpet pad is produced of both synthetic and man-made fibers.

Carpet Cushion is Environmentally Friendly.

Today, much of this cushion is produced from recycled materials. The carpet cushion industry has become green for they continue to become more-and-more environmentally friendly with their carpet pad manufacturing methods.

Bonded cushion from trim generated by polyurethane fabrication facilities that serve industries such as furniture and bedding.
Natural felt cushion is routinely manufactured from recycled burlap bags.
Synthetic felt cushion is manufactured with recycled carpet waste as its major component.
Textile fiber cushion is made from recycled clothing and other post-consumer textile fibers.

Urethane is not Urethane

Urethane or polyurethane carpet cushions represent the greatest number of cushion products used for carpet pad manufacturing. Most of us would believe that urethane or polyurethane cushion contains a blend of the chemical urethane. The fact is, there is no urethane chemical in urethane cushion. This is not a conspiracy of the carpet pad manufacturing business,. The carpet pad manufacturing industry uses the name urethane as used in the plastics industry. Urethane has been designated due to the repeating units of its structure which resembles the chemical urethane.

Urethane in the plastics industry gets its name because it is generally a polymer connected by urethane groups. Urethane linkage and its supplements are a result of the reaction of polyol and isocyanate, whereas the chemical urethane is a colorless, crystalline substance used primarily in medicines, pesticides, and fungicides. While this is one of those pieces of information that you will not use everyday and may be of little interest to the end-user, a professional should be aware of it should the situation arise.

Defining Prime

While the word prime indicates that it is the “best,” the word prime as used by the carpet pad manufacturing industry denotes a group of cushion products that all share particular characteristics. These products include:

conventional prime
grafted prime
densified prime

Producing Prime Urethane Cushion

Carpet pad manufacturing of prime cushion products uses flexible polyurethane foam slabstock chemistry. Support, durability, and firmness characteristics are routinely enhanced by chemical additives. Color is routinely added to the chemical mixture to provide identity to products.

Prime cushion is produced by mixing water, conventional polyols and isocyanates to begin a rapid chemical reaction. This results in carbon dioxide gas, which forms tiny bubbles throughout the liquid mixture. As the gas expands, the polymeric mixture rises like a loaf of bread. The bubbles that form by this reaction will quickly burst allowing the carbon dioxide to escape from the foam leaving behind a uniform cellular structure. The chemical’s mixture is then developed into slabstock or logs.

The slabstock production process is a continuous process where the reacting foam chemical mix is dispensed on to a moving conveyor belt. The expanded foam develops in long flat loafs or buns (normally six feet wide). The buns are slit to the desired size, much like you would slice a loaf of bread.

The log production process involves developing the urethane in a cylinder shape referred to as a log. These polyurethane logs are peeled into the desired thickness, much like you peel plywood veneer from a log.

With both the slit (slab stock) and peeled (logs) varieties, a facing material referred to as scrim is laminated on one side to provide stability and a surface for the carpet to be stretched across. The lamination process bonds the foam and scrim together into a single composite.

Bonding is accomplished through adhesives or through heat processes like flame lamination (also known as flame bonding), which bonds the foam to a fabric or other material (film, etc.). This process melts one surface of the foam with a flame source and quickly presses it to the other substrate before the melted material resolidifies.

Conventional Prime

This is the basic prime cushion and represents the basic industry technology. It is much softer, with many air-filled compartments with multiple open windows which are formed by the surrounding network of elastic struts. This product will not perform as well as the better prime products.

Densified Prime

This cushion provides a unique under foot feel. With densified prime the vertical compression is limited by the oriented cell thickness. The basic concept in densified prime is that vertical struts are stunted and the cell shape is flattened in directional orientation. The vertical compression is limited by the oriented cell thickness at a specified firmness. This is accomplished through controlling the foam rising action through mechanical or chemical technologies.

Grafted Prime

In this cushion, part or all of the conventional polyol is substituted with a special polyol. This special polyol, referred to as a polymer polyol, graft polyol or copolymer, contains minute polymer particulate of styrene and other monomers which extends the harness range beyond that of conventional prime. With the exchange or addition of these reinforced polyols the hardness range of a grafted prime is extended far beyond that of the conventional prime products.

Selecting Prime Urethane Cushion

Prime urethane carpet cushions are manufactured in a variety of products of varied density and firmness. They are normally produced in 6 foot widths in thicknesses of 1/4″ to 9/16″. Of these products the Cushion Council which sits industry standards for carpet pad manufacturing, states: “The best products are those which combine the right balance of properties for comfort and durability.” For a stretched in carpet, this would be a quality cushion that is firm and not thicker than 7/16 inch.

Mechanically Frothed Urethane Foam

Frothed urethane foam cushions are made from a process originally developed to apply cushioned backings to carpet. Air bubbles are introduced by mechanically beating the chemical solution. The solution is solidified by heat and then fabricated into sheets of a predetermined thickness. A facing material is laminated on one side to provide stability and a surface for the carpet to be stretched across. Urethane foam cushioning is applied to a sheet of non-woven material, forming a carpet cushion product with a typically higher density and firmer feel.

What is High Resilience (HR) Foam?

This is a variety of polyurethane foam produced using a blend of polymer or graft polyols. High resilience foam has a less uniform (more random) cell structure different from conventional products. The different cell structure helps add support, comfort, and resilience or bounce. High resilience foams have a high support factor and greater surface resilience than conventional foams and are defined in D3770.

Bonded Urethane Foam (Rebond)

Bonded foam cushions, which are referred to as rebond, are made by combining shredded or chopped pieces of scrap through a fusion process into a single sheet of material. Many grades of bonded cushion are considered to be among the best performing and highest quality carpet cushion products.

Bonded cushion production starts with scrap that is a by-product of foam manufactured for furniture, mattress, auto and other uses. The scrap is sorted by quality and mixed with resins. The mixture is pressurized and injected with steam to form a large block or foam cylinder. The block or cylinder is slit or peeled to its desired thickness. It is at the point of sorting and steaming that much of the differences in bonded polyurethane cushion quality will take place. A cushion that steams longer will generally be a better cushion than one that has moved through this process at a quick pace. Soft scrap without hard pieces and lumps will generally compact better and produce a better cushion.

Selecting Bonded Urethane Cushion

The CRI (Carpet and Rug Institute) recommends for residential installation a minimum density and thickness for bonded urethane of 5#, 3/8″ and a maximum thickness of 7/16″ for light traffic and 6.5# for heavier residential traffic. As these are minimum guidelines, one would be wise to consider upping that to a minimum of 7#. For a commercial installation the density should be at least 12# for optimal performance.

A bonded urethane foam pad has a lesser wear value with the increase of thickness above about 3/8″ and as the firmness decreases. Therefore when you compare the density of the cushion, also compare the composition and firmness to make sure that you are selecting a densely compacted product and not one that is full of heavy scrap and voids or very soft with little resilience.

Fiber Cushions (Felted)

Varieties of this type of cushion are produced from both natural and synthetic fibers. Natural fibers include animal hair, jute, hair & jute blends and rubberized hair and/or jute. Many of the cushions contain recycled material such as jute reclaimed from various forms of burlap.
Synthetic fibers include nylon, polypropylene and polyester. These cushions are most commonly used under commercial carpet and some berber carpet. They are made in widths up to 12′ and in weights from 32 to 85 ounces per square yard.

Both natural and man-made fiber cushions are produced in a couple of different ways. Some are manufactured by a process that basically steams and presses the materials until they become matted into a flat, uniform, felted like surface. Other cushions of this variety are produced by intermingling through a needle bond process, much like that of felt-like outdoor carpets. The needle-bonded products are smoother and easier for the installer to cut.

Natural and man-made fiber cushion grades are measured by weight in ounces per square yard. When using a fiber or felted style cushion you should not exceed a thickness of 7/16″.

A fiber pad should never be too thick or too low in density; in fact, a thick felted pad while more expensive than a thin felted pad has a decreasing value to wear ratio as it exceeds about 7/16″ in thickness. It also has a decreasing value to wear ratio as the density decreases below about 48 ounces per square yard.

Sponge Rubber

Flat Sponge (Slab Rubber) has a flat surface without the ripples.
Rippled Sponge (Waffle Rubber) has a rippled or waffled surface.
Sponge cushion is manufactured with both synthetic and natural rubber along with other chemicals that include both oils and fillers. The mix expands when air is mixed into the batch by chemical means and is formed into either a flat or rippled slab. A material is bonded to the surface and this adds stability and provides a surface that the carpet can be stretched over. These cushions are made in widths up to 12′ and in weights between 41 and 120 ounces per square yard.

Double Stick Cushions

A variety of cushions from sponge to needle-bond synthetics have been produced for these installations. On double stick installations it is important that the carpet manufacturer’s specification for carpet cushion has been adhered to.
The Carpet Cushion Council is an industry leader when it comes to carpet pad manufacturing, and they make the following selection recommendations.

1. The heavier the traffic, the thinner the cushion. In heavy traffic areas like hallways, stairs, rooms with lots of activity and rooms with heavy furniture, such as dining rooms, choose thinner (3/8 inch and less) and heavier cushion to better protect the carpet.

2. For bedrooms, dens, and areas where a more luxurious feel is desired, thicker and more resilient cushion can be used. But again, it’s best to go with higher ounce weight or higher density products to help make the carpet last longer.

3. Visual appearances of cushion are nice, but remember, once it’s installed, you’ll never see the cushion again. Pay more attention to ounce weights, densities, and thickness when buying.

4. Don’t scrimp. Remember, your new floor covering is a system of both carpet and cushion. If you cut corners on cushion, you could be cutting the usable life of your carpet.

For more information of carpet cushion Carpet Cushion Council

Carpet Choices for Wall to Wall Carpet

By Terry Weinheimer 2 Comments

Carpet Choice is almost Limitless

Carpet choices are almost limitless for wall to wall carpet. There are carpet choices in color, carpet choices in style, carpet choices in texture and carpet choices in fiber. Carpet is also manufactured in many different qualities from those designed for no more than a quick cover up, to qualities designed for excellent performance and those where a particular appearance is the most important feature. As you can see, there are many carpet choices and these are all considerations that you will want to make when considering the carpet options available to you.

Two popular carpet choices are tufted loop pile and tufted cut pile. With a loop pile the yarn is tufted or pulled through the backing of the carpet creating a loop. With cut pile carpet the loop is tufted or pulled through the back and the loop is cut which leaves the cut ends standing erect.

Many people consider cut pile to be the best carpet choice as they find it to be more stylish and a looped carpet to be more casual. Cut piles come in many styles, such as shag, textured, saxony, and velvet. Loop pile choices include Berber, cable, or sisal. For high traffic areas, loop pile is an excellent choice.

One of the factors with choosing your carpet is the cost. For years wool carpet has been considered the hallmark for style. Unfortunately a good quality wool carpet is more expensive than most of us can afford. And the cleaning takes time too. Manufactures have made it a practice to emulate wool in many of their synthetic products creating a good-looking and good performing product and affordable costs.

Carpet choices for synthetic carpet yarns are available in continuous filament and spun yarns. While a spun yarn will look more like wool it will also shed more. Many people find their vacuum bags and canisters filling up with carpet fuzz. This is normally because the carpet is manufactured from a spun yarn and is a normal characteristic and not a defect.

If you are able to afford good quality wool carpeting,this can be an excellent carpet choice. You’ll find that even though it costs of wool carpet is more to purchase and install, it will prove to be far more superior to any other type of carpeting. While there is some wonderful man-made carpet fibers that come close to the durability, rich look, or even the feel of wool they still have a ways to go before they are perfected to the quality of a wool carpet which can both last and look good for 30 years or more.

Nylon carpeting is also a popular carpet choices, recommended for high traffic areas. Nylon is an easy to work with fiber enabling manufacturers to created unlimited styles, patterns and colors. Nylon is one of the most expensive types of synthetic fibers, although it is still cheaper than wool.

Olefin is a low-cost carpet material, often used for indoor or outdoor carpeting. Olefin is colorfast and strong, very easy to clean. One of the draw backs to olefin is that it can easily be crushed.

Another consideration you’ll have is the color and patterns of the carpet. Light carpeting colors help to create a spacious effect, making the room appear to be larger. Since light color carpet reflects light it will show soil and foot prints easier than your darker colors.

When looking for soil hiding qualities for homes with pets and children your darker colors are usually a better choice. Fortunately there are many carpet choices in dark colors, which is great for those interested in style. Dark colors are ideal for stains or pets, as they don’t show soiled areas near as much as light-colored carpets.

Don’t let the fact that a carpet has been treated for stain resistance make you comfortable in selecting a light-colored carpet. If you have children and pets and must have a lighter colored carpet be prepared for the extra care when it comes to stains and spots.