Definition of Conductive Flooring
For the full guide to ANSI/ESD S20.20 flooring specifications, see here.
Moving feet and contact with objects generate triboelectric charges. Static sensitive areas require a grounded flooring surface which is slightly conductive but not overtly. ANSI Defines conductive flooring resistance as LESS THAN 1 Million (106) Ohms. Conductive flooring systems provide the lowest charge generation and quickest charge dissipation for an ESD production environment. The flooring is grounded through a copper strip which connects to the flooring to a grounded connection such as a wall outlet.
What Is ESD Flooring, and Is It the Same Thing As Anti-Static Flooring?
In any environment, the movement of people and objects create constant risks of electrostatic discharge from a host of sources.
ESD flooring, also referred to as static control flooring, is an encompassing term for flooring materials and systems designed for use within ESD sensitive environments.
Requirements of An ESD Flooring System
- A) That the flooring system does not generate triboelectric charges
- B) The ESD flooring system has a direct path to ground as a pathway for dissipation of statically generated charges.
- C) Technical Specification of ESD Flooring for product qualification and verification compliance
Definition of ESD flooring: “An ESD Flooring system serves as a conduit for an electrical static charge (known as BVG or Body Voltage Generation accumulation on a person from movement across a surface) to discharge to a desired controlled ground point.” – PI Industrial
Surfaces With Anti-Static Characteristics
Some surfaces like concrete or vinyl floors may provide anti-static properties under the right conditions, and thus potentially considered anti-static flooring. Yet, non-treated floors or even static coated floors (see below) do not provide controlled dissipation or grounding of triboelectric charges. Therefore, the difference between anti-static flooring and ESD flooring is significant. Insulative materials are not considered anti-static.
What is Antistatic Flooring?
Anti-static flooring reduces, removes, or prevents the buildup of static electricity. Therefore, ESD flooring systems fit into this definition, but the terms are not interchangeable. While some materials can provide less charge buildup when used for flooring, dedicated static control flooring systems require a connected ground so that charges can dissipate safely.
The Differences Between Static Dissipative, Conductive, and Insulative Flooring
Static Dissipative Flooring
ANSI defines “Static Dissipative” as anything with a resistance between 1 Million (106) Ohm’s and 1 Billion (109) Ohms. Tile-to-tile systems of rubber sheeted variations to ensure a continuous static dissipative service throughout the space.
- Electronics, plat panel, and medical device manufacturing
- Cleanroom manufacturing
- Computer and electronics handling, assembly or repair
- PCB soldering or rework
- Telecommunication installation areas
ANSI Defines conductive flooring resistance as LESS THAN 1 Million (106) Ohms. Conductive flooring systems provide the lowest charge generation and quickest charge dissipation for an ESD production environment. The flooring is grounded through a copper strip which connects to the flooring to a grounded connection such as a wall outlet. One copper grounding strip is required for every 1000 sq. ft. of ESD flooring.
- Hospital OR’s still using flammable anesthetics
- Extremely sensitive electronic and computer equipment in manufacturing assembly and test areas.
- Some clean rooms with extremely sensitive equipment
- Extremely sensitive telecommunication installation areas
- Medical diagnostic instrument areas with extremely sensitive instruments
Electrically conductive flooring is sometimes referred to as anti-static conductive flooring, defined by an electric resistance of between 10^4 and 10^15 ohms.
Types of ESD Flooring and Prices
ESD flooring has multiple construction and configuration options, each of which varies in price, anti-static properties, and conductivity including:
- Conductive and non-conductive vinyl sheet flooring / Seamless ESD tiles
- Interlocking ESD tiles
- Dissipative carpet tiles
- ESD flooring rolls
- ESD mats
- ESD floor finish
Dangers of ESD Discharge and Voltage of Discharge For Static Shock
The shock generated by touching a doorknob after walking across a carpeted floor in socks is about 25X as strong as the shock needed to spark most vapor or gas clouds. For humans to feel the effect of static electricity, the discharge must reach at least 3500 volts, while as little as 20V could damage sensitive electronics and charges beyond 1400V could set off an explosion. Therefore, any charges generated by walking through ESD hazard areas must be neutralized as quickly as possible. Superconductive flooring would be found in places like munitions plants and warehouse, chemical processing, and fireworks production. Importantly, highly conductive mats increase the risk of electrical shock for the operator when used in conjunction with high voltage equipment.
Non-Conductive Rubber Flooring / Insulative Switchboard Mats
Non-conductive or insulative mats and floor runners, also known as switchboard mats, use insulative materials that prohibit the flow of electricity and prevent deadly shocks. They are often used as localized workstation mats. The dialectic strength provides an insulative foundation for workers exposed to high voltage equipment of up to 50,000V.
Industrial ESD Epoxy Flooring
For more information about ESD epoxy and other static-free floor coatings, read here.
ESD Safe Flooring Requirements
ANSI/ESD S20.20 is a process based document which provides parameters for a standard set of test methods for evaluation of ESD safety. These three segments define the conductive flooring specification
“ANSI 20.20 ESD calls for a combined resistance of the floor AND the person (cumulative) to have a resistance LESS THAN 35 Million Ohms. This is somewhere between 10,000,000 (107) Ohms and 100,000,000 (108) Ohms. Electrical Safety Standards call for the floor to have a resistance of NO LESS than 25,000 (between 104 and 105) Ohms. So now we have narrowed our range down to 104 to 108 Ohms. Throw in some safety margins and we can narrow it down to 105 and 107 Ohms. Now we have a tight specification we can test for and clearly establish as PASS/FAIL for our flooring.” – Safteng.net
For the full guide to ANSI/ESD S20.20 flooring specifications, see here.
How To Install ESD Flooring
You can learn more about the process of installing conductive sheet flooring in the video below.
Choosing Proper ESD Flooring and Where To Buy Static Control Products On The Internet
ESD flooring and static control sometimes often requires a specialized professional for critical environments. Some flammable liquids and industry-specific standards for vapors or gases may require higher or lower resistances. This article provides a framework for understanding ESD flooring guidelines but is in no way a replacement for an accredited safety and materials professional. Context is an important part of making any decision about an ESD control system.
How to Get An ESD Flooring Quote
You should never have to pay for a quote on ESD flooring in your facility, nor leave exact specifications to guesswork. The purpose of the information provided here is to help you make an educated purchase and explore your options when determining what type of ESD flooring is ideal for your application, ESD/ANSI requirements or ISO class specification. Production Automation (that’s us) enables the design and supply of critical-class static control products for hundreds of manufacturers, government organizations, universities, and fortune 50 companies.