In this installment, we’ll look at streaks and lines in broadloom. These conditions occur at the point of manufacture and would be categorized as visible defects-the things you see when you unroll the product or your customer notices after the carpet has relaxed and been vacuumed several times.

Actually, many of these things should be caught at the point of manufacture. The exceptions would be dark soil lines, which show up after the carpet has been put into use, but we’ll talk about that later.

Most common will be lines, which are high or low in the carpet. For example, one low line running the length of the broadloom is the result of too much tension on the yarn. The tension can come from various devices, depending on the machine and the construction of the carpet. This type of defect cannot be repaired.

Opposite that is a high line, also a yarn tensioning condition, but when too much yarn is being led. High lines can often be repaired by trimming them to the same height as the surrounding yarns using duck billed napping shears.

Lines which alternate (high-low, high-low, etc.) along the length of the product are called gauge lines. These are caused by machine set-up, adjustment and yarn tensioning. Often referred to as “corn rows” because they look like rows of corn in a field, gauge lines usually show up after installation and they cannot be corrected.

Short rows of yarn that may look low, slightly higher and more congested are mends in the carpet. Mending is done when a yarn breaks and leaves a void in the carpet. This occurs at the tufting machine. A good mend will be virtually indistinguishable; a bad mend will show up as a flaw which cannot be corrected.

Zigzag lines running the length of the carpet are low lines, which we described as a tensioning issue. The lines zigzag because the tufting machine is a staggered stitch or step over stitch tufter and, as such, the yarn is not tufted in a straight row; it is intentionally staggered to hide streaks or to make a pattern.

There are also lines or streaks in carpet from an errant yarn, a yarn which has been scuffed or damaged, heat set or processed differently. Streaks from this type of inconsistency are not noticeable until the carpet is dyed.

Another type of low line, which runs in short lengths across the face of the carpet, is a shift mark. The yarn being starved or pulled down as the needle bar doing the tufting is shifting back and forth causes shift marks. Shift marks are indicative of a step over stitch construction and cannot be corrected.

All the conditions we’ve just described are inherent in the carpet and are visible defects. There are other defects which have to do with tensioning and lines in the carpet, but the aforementioned are most common. They can be seen, and should be, at the time of manufacture. However, there are also lines which will manifest themselves after the carpet is installed.

The most common “line” which appears after installation is a crush mark. These are caused by the weight of the carpet upon itself. They are not defects and can almost always be eliminated by steaming the carpet correctly, if it is nylon. If it is polypropylene, crush marks will be permanent. This is not a defect, but a handling, storage, or shipping condition.

Another type of streak or line in the carpet comes from oil or some topically introduced substance. Oil will create a dark line which will start faint and grow increasingly darker with use.

Causes of dark lines

A clogged jet or over-application of a soil retardant can also cause a dark line. Yes, too much soil retardant is a soil attractant. These types of lines can almost always by serviced or removed completely without any detrimental effect to the broadloom, if you know what you are supposed to do and do it properly. Improper servicing for removal of this type of line can permanently damage the broadloom.

This is a brief explanation of the most common lines in carpet. If you have a specific problem or question, give me a call and I’ll help you.