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Second Edition


A field reference Guide for Carpet & Textile Inspectors

The Author:

James (Jim) B. Smith has been involved in the carpet-cleaning/carpet-inspection business since 1975. He is a native Texan although much of his work has been in California. At the time of this publishing, he lives just outside of Dallas and owns JBS Consultants Inc. In addition, he is affiliated with the Academy of Textile and Flooring of Whittier California and does volunteer work with the INSTITUTE of INSPECTIONS, CLEANING, and RESTORATION or IICRC. His studies include engineering and chemistry at Texas A&M University and the University of Houston. He is an IICRC Senior Practicing Inspector, Master Cleaner, and an IICRC instructor. He owns the domain, http://www.carpetinspector.com which is a rich resource of information.


The chemicals that damage carpet are well established. Sodium hypochlorite causes color loss and dissolves wool, hydrochloric acid also causes color loss and destroys cellulosic and synthetics. Urine damages fibers and causes color loss, formaldehyde destroys red dye, and hydrofluoric acid destroys yellow dye. However, knowing what chemical is the culprit is the problem. The advancement in chemical and electronic technologies has allowed the carpet inspector to identify those chemicals.

The first edition of this manual was written when all this stuff was new and/or had dramatically dropped in price. A new flat surface pH probe allowed direct contact with flat surfaces like level loop-carpet; pocket size pH meters were fairly new. For roughly $50, a package of strips could identify chloride from bleach or hydrochloric acid, or ammoniated salts from urine, and formaldehyde or for a few hundred dollars could buy electronic probes to do the same thing.

However, the longevity of some of these tools was not very good. Ammoniated salt strips for urine had to be refrigerated. The flat surface pH probe dried out if it was not properly cared for and it need constant replacement. We have seen what can go wrong in court when too much information is introduced as evidence; urine evaluation can rest upon a black-light, moisture meter and pH pen. Finally, formaldehyde and hydrofluoric acid were seldom found making an investment in tools to discover it not practical for most inspectors.

A lot of new stuff this in the market place and the inspector is having a chance to look at those tools too. For example, ultra violet LED lights are coming into the market place. Much is changing with moisture meter that was not available in the 1990s. The ASTM standards for moisture in concrete are continuing to evolve that involve these new meters.

Revisions for this second edition are based upon observations of how these tools are and/or have not been used and the introduction of new stuff. Considerations are based upon the affordability of these tools, how they are used, how rugged they are, and how portable they are. For example, the flat surface pH probe may not be practical for every inspector.



This field reference guide is designed for making first assessments of the identification of chemical substances that adversely affect the performance and aesthetics of textiles. The results derived are suitable for forming an opinion on small claims. A more definitive determination can be by sending samples off for laboratory testing.

The recommended supplies are based upon experience and not commissioned from their source. The topics covered are:

  1. pH
  2. Urine
  3. Sodium Hypochlorite, Bleach like Clorox and Perex.
  4. Hydrochloric Acid


Inspector’s specializing in ‘Appearance retention’ may want to purchase all of the items mention is this manual; the other should look at the essentials needed on most inspections. The common conditions that cause color loss are bleach, urine, and high pH detergents. The tools necessary to detect these include:

  1. Ultraviolet Light
  2. Moisture Sensor
  3. pH Meter
  4. Chloride Titration Strips

In addition, there are various oxidizing or reducing agents in consumer and professional products that include, but are not limited to, benzol peroxide common to acme medications, foot-powders, anti-graying hair products, bug sprays, plants foods, furniture polishes and pesticides. The tools mentioned above will not always be helpful on determining these items.

Finally, there are the less common elements that can cause color loss of which there are testers for. They include

  1. Hydrofluoric acid, which can destroy yellow dye and
  2. Formaldehyde which can destroy red dye.

Order in which to use the equipment

A proper inspection begins with ultraviolet light. If reflections are found, check for moisture reading. if moisture is found, then it likely has a pH reading different from the rest of the carpet. A test strip or probe could be appropriate at this point.

The ultraviolet light

The ‘UV’ light may be mercury, fluorescent, or LED. Prices vary from $20 for battery powered, six inch, fluorescent to $350 to $400 for 150 watt mercury types. However, wattage alone will not describe how much ultraviolet light is emitted since efficiency may be as low as one percent. LED types come close to 100 percent efficiency.

Ultraviolet rays will emit reflections from most seam sealers. A blue white reflection comes from most laundry detergents, a yellow reflection from most urine spots, and a blue reflection from inappropriate detergents. The manufacturers of stain resist carpet prefer they not be used on their product. In addition, when they are used, their ‘blue’ reflections can degrade into red, orange, or yellow reflections. If their source is from laundry detergents, they can be stable in sodium hypochloride; if they are from other types of cleaners, they may become invisible in 3% hydrogen peroxide.

Ultraviolet lights can also be used in spotting. Using UV alone for mustard is far superior to using cycles of acids and enzymes. When used with oxidizing agents in removing dye stains, it can be more effective than using it three times the amount of chemical and with less chance of removing the color of the carpet. Finally, research is currently being done on removing the toughest of all stains, the furniture stain with ultraviolet light.

Your choices are given below:

  1. The battery powered, six inch fluorescent is not worthwhile. Their quality has not been reliable and the rays have been poor to worthless in detection.
  2. The 18 inch, 15 watt fluorescent dominates the market place for both carpet inspectors and carpet cleaners. Price varies from $40 to $80. It is reliable for detection; however, there may be quality issues with plastic bodies breaking, blasting, and/or burning out. In addition, they often require a ground plug outlet.
  3. The mercury type gives the best performance, but not without a step in price of $350 to $400. The price difference will likely not justify their performance differences. In addition, they are large and heavy. Their bulbs can get hot enough to damage olefin if laid down on carpet before they cool.
  4. LED stands for light emitting diode and is similar to the light emitted in clock radios or some calculators. They come close to 100 percent efficiency making them good candidates for battery power. In addition, the bulbs last almost indefinitely and their size is small enough to fit in a shirt pocket. Finally and depending upon how many bulbs are involved, their performance is often greater than 18 inch, 15 watt fluorescents and only somewhat less than the 150 watt mercury type. Currently Cobb Carpet Supply makes a six bulb light that runs off of rechargeable lithium batteries that sells for $79.95. Cobb Carpet Supply is located in Dallas Texas and their number is (214) 634-2622/ (800) 634-2622.


Moisture Sensors

Moisture testing is essential part of many inspections and is a precursor of problems of mold & mildew, color loss, stains, delamination, and a variety of other problems. Products vary greatly from $20 for small noise makers to units over one thousand dollars. They may be intrusive or non-intrusive. Intrusive moisture meters are preferred for carpet. Results are given in percentages either on analog needles or digital numerically. Intrusive moisture meters take accurate readings deep within the carpet. In addition, insulated pins penetrate alone for separate evaluations for cushions and subfloors.

Two major manufacturers dominate the market.

1.     Tramex from Shankill Co. of Dublin, Ireland do business in the United States care of
Black Hawk Sales Inc.,
28 Pin Oak Drive,

Littleton, CO 80127

Tel: 303 972 7926
Fax: 303 972 7106
Dennis Wieszcholek: dennisw@tramexltd.com
Their products cover a wide range of testers for wood and concrete including
intrusive or non-intrusive meters. A kit for Moisture Testing of Concrete and Wood costs $1098.00.

2.     Delmorst Moisture Meters are designed primarily for wood.
51 Indian Lane East
PO Box 68
Towaco, NJ 07082
Sales & Customer Service
Vince Baldassari EXT 227
Alan Dlugasch EXT 247
Fax 973-334-2657

Intrusive moisture meters will yield a 20% reading on dry skin. Spots that have no reading and no difference in pH with the surrounding carpet are likely due to oil base substances. An eight to ten percent reading may be found on slab foundations. High readings in carpet will be associated with a pH indicating whether the staining substance is acid or alkaline. In addition, high readings will likely indicate a spot that will wick back upon drying.

Recommendations are as follows:

  1. Small hand-held models for $20 are not recommended due to reliability issues.
  2. Noise making/water sensor reveal the presence of water over 17%. A DRI-EAZ HydroSensor either an ‘I’ or ‘II’ for either $125 or $149 is recommended.
  3. The DRI-EAZ Moisture Pro Penetrating Meter, $515 Suggested retail, is the preferred choice for data common to most carpet inspections. It has digital readout, contact readings in wood range from 7-39%. The price includes meter, pins, battery and carrying case.
  4. For non-intrusive select a Tramex MOISTURE encounter non-destructive moisture detector for wood, felt-roofing, dry wall plaster and brick for $338.00
  5. For a kit containing three meters for concrete and wood try Tramex Flooring Inspection Kit / Spring Surface Thermometer: Foam lined carrying case contains Concrete Encounter, Professional Meter, Hammer Electrode with 1.5 inch (40mm) insulated pins, Electronic Digital Hygrometer with Spring Surface Thermometer priced at $1398.00.


pH Meters

What are Acids & Alkalines

Acids and alkalines should be part of the common knowledge of ordinary folks. A reminder of how that is so, is that vinegar is acetic acid and sour tastes come from acids. Examples of alkali include oven cleaner and most detergents. Acids and alkalines are chemical opposites of one another. If mixed together, they will create heat and salty water. There are three aspects of acids and alkalines:

  1. pH
  2. Total alkalinity or acidity
  3. Reactivity

What is pH?

A pH is what one measures when acids or alkaline is mixed with water. There must be water present to have a pH. Water molecules are formed with two hydrogen atoms combining with one oxygen atom to form H2O. When acids or alkalines are mixed with H2O, ions of ‘H+’ and/or ‘OH-“ are formed. The concentration of H+ or OH- is what pH is all about. Thus, it is a scale that goes from 0 to 14, where pure water is ‘7’. The acids are from ‘0 to 7’; ‘7’ is neutral; and alkalis are from ‘7’ to ’14.’ Each whole number change in pH represents a ten fold change in the concentration of either H+ and/or OH-.

Rules are based upon pH and that is why pH meters are essential i.e. the makers of stain resist nylon say that the fiber should be cleaned at a pH of ‘10’ or below. Wools of New Zealand recommend cleaning woolen fiber between the pH of 4.5 to 8.5.

What is total acidity or alkalinity?

Acids and alkalines are the ions that make water change into H+ or OH- ions. Thus, acids and alkalines can exist without water and if they do, there is no pH to measure. Examples of acids without water are fluorine or chlorine gases; examples of alkalies without water would include sodium, (Na+) or potassium, (K+). In addition, nylon and concrete are alkalines that at some phase do not mix with water. However, nylon and concrete will react with acids.

Whereas the concentration of H+ or OH- determines the pH, the concentration of acid or alkaline may not determine the pH. When acids or alkalines in water do not regulate the pH, the acid or alkaline is said to be a ‘buffered’ solution. Thus, many acids and alkalines have unique pH i.e. sodium tripolyphosphate has a pH of 9.4 at most reasonable concentrations.

Therefore, the differences between acidity and alkalinity begin to take on meaning when an acid with a pH of ‘6’ mixed with an alkaline of ‘8’ and the result is not a pH of ‘7’. The reason this could occur is because the acid and/or alkaline could be buffered. With an understanding of acids and alkalinizes the reason why WoolSafe approves of a cleaner with a pH of 9.5 that does not damage wool. In addition, it explains why some cleaning products with a pH of 8.5 will damage wool, because they are well buffered.


Finally, there is the issue of reactivity. A well buffered solution of Sulfamic Acid has a pH less than ‘1’; however, it does not react or damage fibers or tools. In addition, the United States Department of Transportation does not consider it hazardous, because it is not a reactive acid. Thus, an inspector should not be alarmed or puzzled when a pH reading of ‘1’ is found, yet there is no damage. In addition, an explanation may be needed to explain why weaker acid or alkaline could create damage.

History of field measuring

It has only been since the mid 1990s that it has been practical to take a pH meter into the field for testing. In the 1970s, litmus paper was the product of choice. Often litmus paper would give a limited range of pH and the dye would sometimes drip onto the fiber. In the mid 1980s, color fast strips made their way into the industry and the range and dripping problems were fixed. However, the strips were accurate to one whole number and at an approximate cost of 15 cents, each, numerous tests could add up to several dollars. Thus, when electronic meters became small enough to fit in a shirt pocket and their price became affordable, they became the preferred choice of measuring pH.


Whereas pH meters are more accurate than colorfast strips, accuracy should go over ‘0.1’. Only differences of ‘0.3’ are meaningful and will show whether an acid or alkaline caused the problem. Meters accurate to ‘0.01’ constantly change in the one tenth and one hundredth ranges and offer no meaningful information.

Meters need to be calibrated to be accurate. Therefore, buffering solutions should be acquired at the time of purchase of the meter and calibrating procedures should be done periodically to assure accuracy. However, accuracy is not as important was one might think; after all it is carpet not laboratory samples that are being tested. Relative differences as low as ‘0.3’ between spotted and unaffected areas determine if acids are alkalines are the problem.

Temperature can affect pH and meter costing around $60 will automatically adjust for temperature. This is not a critical item to be recon with, but it is a consideration when the price is not prohibited. Given that some meters offer ‘0.01 accuracy and automatic temperature control, pick a less expensive one that offers neither of these features.

Most pocket sized pH meters combined the meter and probe into single unit. Prices vary from less than $40 to around $80. A problem with these meters is that the probe is recessed in a protective chamber that limits contact on flat surfaces such as level loop carpet. However, the probes on these meters are durable giving years of service and aside from changing the batteries every year or so, they require very little care. This editor’s choice is the pH Pen, P307 - $38.50 from Tri-Ess Sciences, 1020 W Chestnut, Burbank, CA 91506-1623, phone (818) 848-7838, web page http://www.tri-esssciences.com

For those who need a flat surface, the meter and probe will come separate and a cable will join the two. For the meter, the editor’s choice is the pocket pH Testr from Markson Labsales, P.O. Box 3616, Honolulu, HI 96811-3616, phone (800) 528-5114, web site http://www.markson.com  Priced at $59.00 its catalog number is 6613-1629 and the probe Flat Surface Catalog number M1208B $75.00. Whereas the probe will make direct contact on flat surfaces, they are not durable. In addition, the probe comes with and must remain in a soaker bottle. If the probe dries out, it will need replacement.

How to Measure

Water must be applied to the affect area and to non-affected spot. The non-affected spots can be very close in proximity to the affected spot. The best applicator is trigger sprayer applying a mist. The more water that is added, the more the pH will shift towards ‘7’. The flat surface probes have an advantage here on requiring the least amount of water. Next, agitate the areas for testing with a clean bone scraper. Agitating with a towel or a hand can help corrupt the readings by introducing other substances to the spots. If the probe has been sitting in another solution such as a soaker bottle for the flat surface probe, then rinse it off with tap water. Apply the probe to the area to be tested and ignore the first two or three readings. Agitating the faceyarn with the probe will give better results and dragging it from the problem area to an adjacent area can reveal a wealth of information. However, using the probe in this manner with short its life, especially on the flat surface probe.

Interpreting the Readings.

The chart below is a guide for interpreting the readings on digital pH pens.




Additional Action


Less than 3

Strong Acid, toilet bowl cleaner, tile cleaner

Test for Chlorides to determine Hydrochloric Acid


3 to 6

On new carpet, Acid dye lock

Check Colorfastness at higher pH


From 3 to 6.0

Food Related

Try spotting with enzymes


4.0 to 5.5

Acid Rinse



6.0 to 6.7

Typical pH for Soil

Typical pH for Soil indicating no recent cleaning.


0.3 to 1.0 less than surrounding carpet

Likely Urine

Run one to three other tests to confirm urine.


Less than 4 or 2 points lower than surrounding carpet

If the spot is a color loss and there is a sulfur smell, then a reducing agent like sodium hydrosulfite is responsible.

Rinse and then neutralize the spot with hydrogen peroxide. Then repair the color.



Neutral Rinse



7.3 to 8.0

HWE with Stain Resist Detergent



8.1 to 8.7

HWE with pH 10.0 Detergent

Recommend acid rinse in cleaning


8.8 to 9.2

HWE with High pH Detergent

Recommend acid rinse in cleaning. Look for bleeding.


9.5 & higher

Oven Cleaner or bleach

Test for Chlorides to determine Sodium Hypochlorite

Numbers are bases upon five years of collecting field data.



There are six indicators for urine.

1.     Yellow stain either darker or lighter than the surrounding carpet. If the yellow stain is darker, then color has been added to the carpet. If it is lighter, then blue and/or red have been destroyed. A yellow stain by itself is not enough to say that urine is present. If it is combined with odor, then chances of it being urine are excellent; if it shines yellow under ultraviolet light, then it is likely urine. But there again, it could be a yellow high-lighter. If it has a moisture reading, then change.

2.     Urine smell that can degenerate into a rotten egg odor. If there is a urine smell coming from yellow stain, then the evidence is likely good enough for small claims. Even though a urine smell is strong evidence, the lack of an odor is common, especially where some deodorants have been used.

3.     Yellow reflection under ultraviolet light. For some carpet mills, that is all they want. However, urine is not the only thing that shines yellow under ultraviolet light and sometimes old urine does not shine at all.

4.     Moisture reading that will occasionally go off the scale.

5.     Acidic pH reading. Since relative readings are what is important, a reading that is 0.3 less than the surround carpet can be an indicator of urine.

6.     Ammoniated Salts which can be measured with an Ammoniated Strips, Markson catalog MXR246529 for $49.00 The ammonium strips requires refrigeration. Ammonium salts, (NH4+), are not found in cleaning compounds and it is not to be confused with quaternary ammonium chloride which can also turn stain resist nylon yellow. If ammoniated salts are not found, then it is very likely that the spot was not created by urine. The urine odor is an amine compound which is closely related to ammoniated salts.

If either a reflection or a smell is inconclusive, then check for moisture and/or pH. Moisture readings in excess of 17 percent are good enough to support micro- organisms. A pH reading lower than the surrounding area (generally in the low 6s) is also indicative of urine. Having both moisture and lower pH is strong evidence.

The chart below is a guideline on how to evaluate combinations of results. The ‘+’ indicates that that line item combined with that number plus any other item, i.e. any combination of three.


Do more testing

Fair Chance

Good Chance

Excellent Chance

1.   Yellow stain

By itself

2 or 3 or 4

3+ or 4+ or 5+

Plus 3, 4, & 5

2.   Urine Odor



By itself

Plus any

3.   UV Reflection

By itself

1 or 4 or 5

1+ or 4+ or 5+

Plus 1, 4, & 5

4.   Acidic pH

By itself


1 or 3

Plus 1, 3, & 5

5.   Moisture

By itself

1 or 3 or 4

1+ or 3+ or 4+

Plus 1, 3, & 4

6.   NH4 Salts

If none is found


By itself

Plus any



Chlorine bleach is a strong alkaline and hydrochloric acid is a strong acid found in toilet bowl cleaners and tile cleaners. They both create a loss of blue and red dye often leaving a yellow stain. On wool, sodium hypochlorite, CLOROX® type bleach, will dissolve it, but hydrochloric acid will have little effect. On synthetics, hydrochloric acid will go beyond damaging the dye and damage the fiber more often than sodium hypochlorite.

The element Chloride, (Cl), is what both sodium hypochlorite and hydrochloric acid share in common. The QUANTAB® TITRTORS Strip is the tool that determines if it is present. Whether the problem is hypochlorite or hydrochloric depends upon the pH reading. Sodium hypochlorite will have an alkaline pH from eight on up to tens and higher in most cases; hydrochloric acid with have an acidic pH. Most of the time hydrochloric acid’s pH will be in the ones and twos, but can be as high as six.


1.     Upon locating a light colored stain, check for ultraviolet reflections. Chlorine bleach is often mixed with laundry detergent that has a blue/white optical reflection.

2.     Check for moisture. The higher the moisture readings, the greater the concentration.

3.     Determine the pH with a little distill water as possible.

4.     Now soak the areas with more distill water and place a QUANTAB® TITRTORS Strip in affected area and one or more in non-affected adjacent areas. The base of the QUANTAB® TITRTORS Strips should be wedge between the yarns so that its base comes close to touching the primary backing.

5.     Wait! The base of the QUANTAB® TITRTORS Strip will begin to discolor from the base to its tip. When a relative difference is established, then take a reading and/or a picture. The amount of time this takes will vary from a few minutes to 15 minutes.

6.     Conclusion. The relatively higher concentration of chlorine with an alkaline pH will indicate chlorine bleach i.e. sodium hypochloride. An acidic pH reading with relatively higher concentration of chlorine will indicate hydrochloric acid.


This manual represents an accumulation of the work of many inspectors involved in identifying substances that can adversely affect a carpet. As technology changes, this manual will steps forward with updates and will endeavor to advance forensic floorcovering investigations.