Carpet wear testing in the lab is primarily used to evaluate new carpet prior to placing it on the market. Carpet wear testing in the lab can also be performed on unused remnants of carpet from an installation. There are also carpet wear testing or evaluation methods that can be performed onsite by trained carpet experts.
Carpet Wear Testing and Evaluation
The certified carpet inspector, experts from the Weinheimer Group are often called upon for carpet wear testing and to evaluate wear on installed carpet installations. When arriving at a site we often hear the statement, “My carpet is wearing out.” It is possible that it is wearing out though more than likely the carpet is experiencing “Ugly Out.” With ugly out the carpet is worn out as far as appearance but not as far as actual wear the way it is interpreted by the carpet industry.
Today most carpets are manufactured with synthetic yarns. Synthetic yarns are nearly impossible to “wear out” when wear is based on the standards set forth in the warranties of most every carpet and yarn manufacturer. Manufacturers wear warranties for the most part protect the manufacturer and not the consumer. These warranties will usually only cover abrasive wear with most of them calling for a number such as a 10% loss of fiber as a result of “abrasive wear.” Abrasive wear caused by foot traffic. The warranty will probably say something like this, “This carpet will not experience fiber Loss from Abrasive Wear Caused by Foot Traffic (as hereinafter defined) by more than 10% in any area except stairs. “Fiber Loss from Abrasive Wear” is defined as actual loss of fiber, due to abrasion, from the surface pile of the carpet and does not include damages caused by or resulting in matting, crushing or “watermarking.”
In this article we are limiting carpet wear testing to that performed in the laboratory by companies such as Independent Textile Testing and Professional Testing Labs. In other articles we will discuss onsite testing.
Carpet Wear Testing in the Laboratory
Surface Appearance Changes in Pile Yarn Floor Covering
ASTM D5252 Hexapod Drum Tester is a 12″ diameter-rotating drum that new carpet specimens are placed in for carpet wear testing. The samples are subjected to a metal ball with six attached polyurethane cleats or studs to simulate traffic.
ASTM D 5417 Vetterman Drum Tester is a 28.75″ diameter-rotating drum that carpet samples of similar pile height are placed into. A 16-pound ball with polyurethane studs tumbles inside the drum to simulate traffic and wear.
ASTM D 6119 Foot Traffic is a method of testing that creates surface appearance changes in carpet from foot traffic. Using a normal walking pace without scuffing, individuals walk across the specimens, which have been arranged in a particular walking path. Foot traffic units are calculated either by photoelectric or hand held manual counting devices.
Carpet wear testing in the laboratory for surface appearance change, 20,000 foot traffic units is the recommended standard for household applications. ASTM D 6119 – 97 section 10.1
Section 1.2 states, “This practice is applicable to most changes in surface appearance observed in all types of carpet that are intended for residential or commercial use. It eliminates change in appearance associated with soiling by focusing on appearance change due to matting, flattening, or change in pile fiber configuration. Although “pile reversal” or “watermarking” is occasionally visible, this practice is not a reliable method for producing this phenomenon.”
During controlled carpet wear testing the carpet is vacuumed every 1000 foot traffic units using a dual motor, top-loading, upright vacuum cleaner with a rotating brush.
When evaluating an actual installation onsite we are not dealing with controlled laboratory conditions. Therefore it is important for us to obtain information that will help us to evaluate the conditions.
- Description of the area
- Number of individuals that reside in the residence or in a commercial situation the number of individuals that are normally in the area on a given day.
- Frequency of vacuuming
- Type and condition of vacuum
- Maintenance other than vacuuming
How rapidly will 20,000 units develop in a residence?
Now you can develop thousands of scenarios for an installation. For this discussion I have developed two scenarios, a family of 4 and a retired couple (2). These scenarios are examples and not what would actually be used for carpet wear testing.
Scenario One – A Family of Four
For this scenario, let us use a single-family residence and a family of 4. Both parents work outside the home and the children are in school. In the typical household there are days where the family or part of the family is away from the house for the entire day. There are also days when the children or adults have company which increases the amount of traffic for that period of time. Taking this information into consideration, for the sake of this discussion, 4 people are at this house 300 of the 365 days.
In the typical small house you will have cross traffic from the living room or a family room to the kitchen, service porch, bathrooms and bedrooms. Keeping foot traffic units to the very minimum for the sake of this discussion we come up with the following calculation for each family member.
Foot Traffic Units Family of 4
- 3 trips to the kitchen from the living room
- 3 trips back to the living room.
- 3 trips to the bathroom from the living room
- 3 trips back to the living room
- 2 trips to the bedroom from the living room
- 2 trips back to the living room
- 1 trip when leaving the house in the morning.
- 1 trip when returning to the house in the evening.
- 18 trip total per day per family member. For the sake of this discussion we are not including trips to the laundry room, garage, or extra trips to any area.
Now to calculate the foot traffic units for this scenario. 18 trips x 4 family members x 300 days = 21,600 traffic units. ASTM states 20,000-foot traffic units will produce a noticeable change.
Scenario Two – A Retired Couple
This retired couple is at the residence most of the day, so the foot traffic units will naturally be different than for the family of 4. For this discussion, lets say the retired couple is also there only 300 days per year.
Foot Traffic Units Retired Couple
- 6 trips to the kitchen from the living room to get a drink of water of something to eat
- 6 trips back to the living room.
- 7 trips to the bathroom from the living room (no explanation needed)
- 7 trips back to the living room
- 3 trips to the bedroom from the living room
- 3 trips back to the living room
- 2 trips to go outside during the day.
- 2 trips to back into the house during the day.
- 32 trip total per day per family member. For the sake of this discussion we are not including trips to the laundry room, garage, or extra trips to any area.
Now to calculate the foot traffic units for this scenario. 36 trips x 2 family members x 300 days = 21,600 traffic units. ASTM states 20,000-foot traffic units will produce a noticeable change.
While this is no way scientific as you would get with actual carpet wear testing in the lab, it is a reasonable consideration of use that points out how rapidly traffic change develops in an area.
- carpet, n-all textile floor coverings not designated as rugs.
- change in surface appearance, n-for pile yarn floor coverings, the cumulative change in surface appearance between unexposed and exposed specimens due to crushing, loss of tuft definition, and matting.
- crush, n-in pile yarn floor coverings, loss of tuft definition due to entanglement and compression of pile fibers.
- floor covering, n-an essentially planar material, having a relatively small thickness in comparison to its lengths of yarn to the face of a primary backing.
- foot traffic units, n-for pile floor coverings, the number of passes by human walkers over a specific group of carpet samples.”
- Discussion-Foot traffic units should not be taken as the actual number of times each specimen is stepped on, but rather as the number of times that persons pass a designated spot on the walking course.
- loss of tuft definition, n-for pile yarn floor coverings, the bursting, opening, and untwisting of pile yarn, decrimping of the fibers in the surface pile, or any combination of these.