ESD Technical eNewsletter
ESD Corner Mar/Apr 2001
Issue 3, Volume 4
   Dr. ZAP
Controlling Static Generation In Carpets


Static charges that generate from floors and carpets are not only an annoying occurrence for office and factory employees but can be quite costly as well. Static generation from existing carpets and floors can be easily controlled.

What is static electricity?

Static electricity is an electrical charge that is at rest, as opposed to electricity in motion or current electricity. Static charges can be generated by either contact and separation or induction. Typical examples are the Wimshurst machine that uses friction and the Van de Graaff generator using electrostatic induction.

How is it generated?

The most common generation of static charge is the triboelectric charge or the friction electricity developed when rubbing together and then separating two masses. For example, when two blocks are rubbed together and then separated, one block losing electrons and one block gaining electrons, a triboelectric charge is developed on each block. The two blocks will have opposite polarities; one will be negatively charged and the other will be positively charged.

Static Generation from carpet:

When a person walks across a carpeted or tiled floor, a triboelectric charge builds up in the body due to the contact and separation between the shoes and floor material. The greater the friction and contact area, the greater the voltage potential develops on the body which acts as a capacitor, similar to a “component” holding a charge.

Everyone's capacitance to hold charges is different. However, a sure sign of electrostatic presence is hair standing on end or static discharge sparks. Static discharges can be noticed when you touch an object of lower electrical potential such as a metal door knob, and a small bolt of electricity flows from your charged body to the door knob. This flow of electricity is actually a result of the stored static charge that is being rapidly discharged to the lower potential object.

This discharge that can be felt as well as seen, is commonly referred to as an electrostatic discharge, or an "ESD Event". An ESD event can be as low as a few volts or as high as several thousand volts. You can feel an ESD Event at a few thousand volts, but ESD Events as low as 10 volts can still cause damage to sensitive electronic components.

Tribocharging foot to carpet
discharging hand to metal object

It is not the static charge generated on the body that does the damage rather it is the difference in the two potentials seeking balance that creates an electrostatic discharge. If large enough, the ESD can be felt as well as seen. The ESD event can be felt at the human sensation threshold of 3000 volts. If one feels or sees the static shock, it is a minimum of 3000 volts. The potential static charge that can develop from walking on tile floors is greater than 15,000 volts, while carpeted floors can generate in excess of 30,000 volts.


This can pose quite a problem for environments that contain sensitive equipment or electronic components that are vulnerable to static damage, such as electronic manufacturing, repair facilities or medical facilities including computer rooms and clean rooms. For many companies, it is a major factor adversely effecting productivity, quality, and customer satisfaction.

Controlling the damage and costs caused by ESD is usually the main concern that drives a company to implement an ESD control program. The costs involved with static damage not only include the immediate cost of the damaged component, but the contributing cost of diagnostic and repair labor that is needed to replace or fix the component. In most cases the labor involved will far exceed the component cost. If the damaged component performs enough to pass QC it is called a soft failure as opposed to a hard failure when it does not pass the QC. It is far more expensive for a soft failure occurring at the manufacturer which then leads to a hard failure in the field which escalates product returns and field service cost.


As with any type of controls, there are several levels of protection. The method for choosing the necessary degree of ESD protection starts with defining the withstand voltage or ESD sensitivity for electronic components. There are three classes of sensitivity defined by the Department of Defense standard DOD-STD-1686. Class 1 components are defined as having a voltage sensitivity range from 0 to 1999 volts. Class 2, is defined as a sensitivity range from 2000 to 3999 volts and Class 3, is from 4000 to 15,999 volts.

How can you determine the class of sensitivity of your facility? Look at your product flow through your facility; start at receiving and walk the components or products through until they are at shipping ready to ship. Chances are you have several different product flows through your facility. Each flow or loop will have specific components that enter or travel the loop. Make a list of all the sensitive components in each loop and determine the static voltage sensitivity or rating from each of the manufacturers. The lowest voltage sensitivity will dictate the sensitivity class of each loop ensuring the loop will have adequate ESD protection for the most sensitive components that will travel this loop. This will define what class of protection is needed for each loop. You can have different class loops as long as the loops are closed, not allowing other components in. The objective here is to define an ESD control program to safeguard your most sensitive component.


ESD control carpet and conventional carpet with antistatic treatments can still generate up to 1500 volts, far exceeding the class 1 limits. These carpets, however, when properly maintained, can provide safe grounding and electrostatic propensity below the class 2 and 3 sensitivity range.

Proper maintenance for ESD control carpets is rather simple, but very important. For conventional carpets that are treated with a topical antistat or other treatment (Statproof® Carpet Protector), it is required that the treatment be replenished on the carpet as the treatment wears away due to foot traffic. The amount of treatment on the carpet can be determined by testing with a surface resistance meter. The higher the resistance readings of the floor, the lower the amount of static control treatment that is present on the carpet. The level of treatment should be monitored by resistance readings and kept between 1 x 106 and 1 x 1010 ohms. Some ESD floor finishes can be used as a carpet treatment. This requires a simple spray bottle filled with 50/50 mix of ESD control floor finishes and water. Always check with the floor finish manufacturer before use. Application of diluted floor finish usually requires 1 to 2 spray coats on the carpet depending on the level of resistance required.

ESD control carpets are made with static dissipative yarn and only require that the yarn be kept clean and free of insulative dirt, dust, and spray cleaners.

ESD control floor tiles can also generate triboelectric charges depending on the construction of the tile. The tile, dissipative or conductive, may have voids between the impregnated conductive sections which allows triboelectric charges to be generated and then drained. This cyclic voltage can be very harmful for sensitive components.

ESD control floor finishes alone can provide both non triboelectric charging as well as a path to ground. Such floor finishes can be applied on many surfaces including sealed concrete, vinyl tile, and especially ESD control tiles. If the ESD control tile is generating triboelectric charges, ESD control floor finish will complement these tiles with its non- triboelectric properties, as well as enhancing the surface's electrical properties. The ease of maintenance for an ESD control floor finish is another benefit when used on top of any tile floor, especially carbon impregnated conductive tile that may form streaks of black carbon on the surface.

Ideally, the ESD protected flooring will meet all ANSI/ESD S20.20 Table 1 Flooring Technical Requirements:
  • Dissipative or conductive surface <1 x 10E9 ohms tested per ESD S7.1
  • Provide path-to-ground <3.5 10E7 ohms tested with Footwear per ESD STM97.1
  • Low charging <100 volts tested per ESD STM97.2


The best ESD controls are not only the ones that protect sensitive components and equipment but are: A) at hand and readily available, B) easily maintained. For these reasons carpets and tile floors should not be overlooked as sources for electrostatic control. Existing carpet or tile floors can be easily included into an ESD control program. For more details on testing ESD flooring materials contact ESD Association, 7900 Turin Road, Building 3, Suite 2, Rome, NY 13440-2069 USA. This standard ESD-DS7.1 for "floor materials- resistive characterization of materials" is a straight forward and comprehensive approach for testing ESD control carpets, tile, floor finishes and mat materials.

Referring White Paper:


Try this on your car seats!
Statproof® Carpet Protector
Statproof(r) Carpet and Fabric Protector

  • Reduces the generation and build-up of static charges on carpeting and fabric chairs
  • Provides excellent dry soil and stain resistance
  • Can be applied to fabric chairs, carpet and other fiber materials
  • Water based, easy to apply
  • Trigger spray quart makes product easy to apply to small carpet areas and fabric chairs
  • Coverage: 1,200 sq ft per gallon of concentrate, 25 sq ft per ready-to-use quart

Buy Now    Tech Info 



Our products come with full technical support

Product document support includes a technical brief, drawing or bulletin. These are referenced within our on-line catalog as well as listed in our web site.


Technical Brief



Certification Information



Extra Protection

For added protection, ESD branded personal grounding products are packaged in antistatic low charging bags which are indentified as ESD protecting by the inclusion of the ESD Protective Symbol as Per S8.1 paragraph 4.1.

ESD Protective Symbol

When stocked in the “Kitting” rooms, we supply a complete package that is ESD protective. Remember that the ESD protective symbol should also be used on items designed to replace static generative materials. This provides added peace of mind when bringing in an ESD Wrist Strap/Foot Strap/Ground Cord into an ESD Protected Area as packaged vs products that are packaged in regular high charging plastic bags.

Antistatic and Dissipative Brushes

34100use-180.gif - 4365 Bytes

Our antistatic brushes are made from low charging materials and natural materials that are near neutral on the triboelectric chart. Their propensity is to neither give nor take electrons and, therefore, remain essentially electrically neutral. However, there can be a slight charge created. In extreme voltage sensitive applications, these brushes should be used only in a liquid environment.

Item # 34118 & 34120 dissipative brushes have a surface resistivity of 105 - 1011 ohms, a higher resistivity than the conductive brushes, but sufficiently conductive to preclude any electrostatic build up in the brush. These are excellent tools to use in removing any static charge that will result in the adhesion of particles, such as dust, to an object. Frequent use of these brushes will keep electrostatic charges from building up on your products. Please use these brushes with a wrist strap or other mechanism to provide a path to ground for safety.

Buy Now    Tech Info 


 RED PROGRAM  Click here for more information
When: June 11 - Jun 13, 2001
Where: Boston University Conference Center, Tyngsboro, MA
What: RED Program (NARTE Certification), Co-Sponsered by the ESD Association and the Northeast Chapter of the ESD Association.
Why:Become NARTE Certified with either NARTE ESD Technician or ESD Engineer certificates. For more information, visit us at our web sites:
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Q43: I have some benches on carpet, can I get away with ESD mats and ground straps? - Anonymous, Campbell, CA see ANSWER 43

Q68: Much of our manufacturing floor is covered with dissipative tiles, but a small area is not covered. The floor of the plant is concrete and I was wondering if this is sufficiently dissipative? Would it help to have a conductive coating such as a conductive wax applied to it? - Anonymous, Scientific Atlanta Canada, Burnaby, Canada  see ANSWER 68

Q136: Is it possible to reduce ESD in carpeted floors? We had a "non-ESD producing" carpet installed that does produce ESD. Are there sprays or other treatments available? - Vytas Pazemenas, Aubrey Group, Inc., Irvine, CA   see ANSWER 136

Q199: A few minutes ago I attended an ESD training session given by Mr. Jim Mckeon from DESCO INDUSTRIES, and I asked him about a question that I had on my Physics Ph.D. qualifying exam 23 years ago. He said he did not know the answer and that I should ask you about it. The question was this: "On a cold winter day how many electrons do you collect on your body when you walk across a carpeted room?". My solution to the problem was to estimate a voltage based on the length of the spark discharge from your finger to a metal door knob (taking into account the breakdown voltage of dry air), assume that the average human body can be approximated by a sphere (in which case the formula for the capacitance is simple), calculate the charge from the equation Q = CV, and then divide Q by 1.610e-19 coulombs. But I have always wondered if my answer was correct. Basically, all I want is an estimate of the capacitance of the average human body. Hope you can answer my question! - Anonymous, Oceanport, NJ see ANSWER 199

Q262: I am moving to a leased office, and the landlord doesn't want to remove the carpet in the area designated as the electronics lab. Can you recommend any of your ESD flooring products for use over carpet? Overlaying the carpet with plywood to provide a more solid base would be possible. - Anonymous, St. Louis, MO    see ANSWER 262

Q306: I have a few questions about grounding ESD carpet. 1. What is the best way to connect ESD carpet tiles to earth ground? 2. What is the acceptable surface-surface resistance range for ESD carpet tiles? 3. What is the acceptable surface-ground resistance range for ESD carpet tiles to earth ground and where should the measurement be taken (at which points)? - Anonymous, Milwaukee, WI   see ANSWER 306

Q419: I have a PC user that has used four PCs in the last three months. He has had numerous Microsoft and other mysterious problems; from locking up to Illegal Errors to the appearence of a DOS “Blue screen of Death” explaining that it is OK to shutdown his PC (while the PC was idle). I and other MIS techs have rebuilt two of the PCs, changed memory, motherboards, NICs and other components all to have the problem again occur on the fourth PC this morning. It’s a longshot, but some techs think that we may have a highly charged user that needs grounding. Don’t laugh - it fixed a problem with another user a year ago. What do you recommend to safely ground this individual? He works in a Herman Miller cubicle on carpet. All PC equipment is connected to a surge protector. –Robert Greene, Sacramento County Waste Mgmt, Sacramento, CA   see ANSWER 419

Find more ESD Q&As here


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ANSI/ESD-S20.20 - Floors Personnel Grounding Guidance
The personnel grounding system in all cases includes the person, the control item(s) and connection to ground. A log should be maintained which verifies that personnel have tested their personal grounding devices. Personnel should check constant monitoring devices (when used) to ensure that they are functional and operating before ESDS products are handled. In addition, constant monitoring devices should be functionally checked periodically to ensure that they are operating as designed. ESD protective flooring, used with approved footwear, may be used as an alternative to the wrist strap system for standing operations. Footwear includes foot grounders, shoes or booties. When equipment ground or auxiliary ground systems are not available, bonding or electrical connections (contrived ground) may be used. Refer to ANSI/ESD S 7.1 ESD Association Standard Test Method for the Protection of Electrostatic Discharge Susceptible Items - Resistive Characterization of Materials - Floor Materials.

Flooring/Footwear Systems Standards           Range
ESD STM 97.1: < 35x106 ohm
ESD STM 97.2: < 100 Volts

Flooring Systems
ANSI/ESD S 7.1: < 1x109 ohm

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