Static Control Products
Options in ESD Flooring Conductivity
What's Best for COMPLIANCE in Electronic Manufacturing?
Antistatic, Static Dissipative, Conductive. And the Winner is . . .
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 2 electrodes is referred to as testing the floors 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 floors 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.
DISSIPATIVE: This is an ESD floor with a PTP and RTG of
greater than 1.0E06 and less than 1.0E09. Static dissipative vinyl flooring is manufactured
via 2 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 environments thus rendering the material slightly
conductive. Static Dissipative
flooring that contains conductive fibers (or powders) 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
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 that is required for
compliance in electronic manufacturing.
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.
CONDUCTIVITY: This is a flooring material with a
resistance below 1.0E04. It does not meet the industry accepted safety
standards with a minimum electrical resistance of greater than 1.0E04.
These flooring materials will eliminate the static charge too quickly for
electronic manufacturing. This material is recommended for use by trained
personnel ONLY and it is typically only used in specialty Military and
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