Options in ESD Flooring Conductivity

What's Best for COMPLIANCE in Electronic Manufacturing?

Antistatic, Static Dissipative, Conductive. And the Winner is . . .


Combination Resistance Testing for Compliance to ANSI ESD S20.20 (expand photo with descriptions)

An ESD Floor's electrical conductivity is what takes the static charge to ground (thus eliminating the static voltage). Let's start with the basics of how an ESD floor is tested. Electrodes of a certain size, weight and density are placed on the floor at a certain distance apart. An electrical charge (voltage) is sent through the Electrodes and an instrument measures the resistance between the electrodes in Ohms. Taking readings between two electrodes is referred to as testing the floor's point to point (PTP) resistance. In another test, an electrode is placed on the floor, an electrical charge is sent through the single electrode and the opposite test lead from the resistance test instrument is attached to AC electrical ground. This is referred to as testing the floor's resistance to ground (RTG). Note: On most resistance test instruments the Ohms are expressed as a scientific notation. For example 1.0E06 (6 zeros with a 1 in front=1million ohms). An easy way to keep it all straight is the higher the number after the E the HIGHER the RESISTANCE. By far, the most popular ranges of electrical resistance for ESD Flooring are Static Conductive and Static Dissipative. Let's go over some of the terminology.

STATIC DISSIPATIVE: This is an ESD floor with a PTP and RTG of greater than 1.0E06 and less than 1.0E09 ohms. Static dissipative vinyl flooring is manufactured via two different methods. Either a vinyl material is loaded with conductive fibers OR the material is manufactured without the conductive additives but with "hygroscopic" capabilities. These hygroscopic capabilities allow the flooring to absorb the ambient humidity in the environment thus rendering the material slightly conductive. Static Dissipative flooring that contains conductive fibers typically fall in the range of 1.0E06 to 1.0E07 and are NOT reliant on humidity for their static dissipative properties. Hygroscopic materials typically fall in the range of 5.5E07 to slightly less than 1.0E09 ohms at greater than 50%rH. Some static dissipative floors can make it VERY difficult to achieve the required combination resistance value of carts, chairs and even technicians in heel straps for compliance in electronic manufacturing.

STATIC CONDUCTIVE: These floors have a PTP and RTG of greater than 1.0E04 and less than 1.0E06 (1 Megohm). For electronic manufacturing and other sophisticated static control environments static conductive is the industry preferred choice. Why? Because the combined resistance (see example) of drag chains, chairs, carts and personnel in conjunction with the flooring must be below 1.0E09 (1 Gigaohm) for compliance to the stringent new standards used in electronics. And, it's MUCH easier to achieve this with a floor that starts out in the static conductive range. It's that simple! "But I've read that static conductive flooring is dangerous." Hogwash plain and simple! A static conductive floor has about the same resistance as an ESD wrist strap. Today millions of people worldwide will go to work on an ESD conductive floor and zero will be electrocuted due to working on an ESD (static conductive) floor.

ANTI-STATIC FLOORING: Anti-Static flooring was a phrase coined by the flooring industry (circa 1954) used to describe a flooring material that wouldn't allow a person (when walking on the flooring) to generate enough static to feel the discharge when they touched a grounded object (like a light switch). Keep in mind a person must generate well over 3,000 volts to actually "feel" the discharge! Now-a-days? The level for static generation (when walking on an ESD floor used for electronic manufacturing) is less than 100 Volts! Anti-static is used as a somewhat misleading catch all, generic phrase to describe any flooring material that controls an electrostatic discharge.

HIGH CONDUCTIVITY: This is a flooring material with very low resistance (they may almost be as conductive as standing on a grounded steel plate). These flooring materials will eliminate the static charge too quickly for electronic manufacturing and are typically only used in specialty Military and munitions applications.

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Contact UNITED Static Control Products Inc

11/01/2024

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