ESD Tile : ESD Flooring Terms and Definitions

Mission Critical: Literally, any operation that cannot tolerate intervention, compromise or shutdown during the performance of its critical function. Mission critical environments usually support health, safety, security and human welfare. These environments also monitor, store, support and communicate data that cannot be lost or corrupted without compromising their core function. Since all computer and communications systems are highly sensitive to static electricity, static events pose an internal threat to mission-critical operations, such as flight control towers, energy management operations, 911 centers, command centers, dispatch, control rooms, data storage centers, hospitals, stock exchanges, laboratories, university research facilities, computer rooms—any space where the loss or corruption of data cannot be tolerated. Conductive flooring is a mandatory element in mission critical environments, because it prevents and discharges static electricity before it becomes a problem.

NFPA 99: (National Fire Prevention Agency section 99), the NFPA-99 provides a test methodology for measuring the conductivity of flooring and other surfaces. This test was originally designed in the 1960's for use in hospital operating rooms that used explosive gases for anesthesia. Operating room surfaces were required to be conductive so that static fields would be safely discharged to ground instead of dangerously discharged as a spark that could ignite an explosion

One Hundred Megohms: "One Hundred Meg" equals one hundred million ohms or 1.0 x 10⁸. The exponent, 8, refers to eight zeros after the 1. StaticWorx recommends this electrical resistance measurement as the maximum acceptable level for an ESD carpet specification.

(Note: Many ESD flooring manufacturers will recommend electrical resistance measurements as high as 1.0 x 10⁹, (1 Billion ohms or "One Thousand Meg"). However, StaticWorx feels that the gap between 100 million ohms to a 1 billion ohms is too large, (900 million ohms), of a jump in electrical resistance. If the material's electrical resistance happens to deteriorate over time, beginning at 1.0 x 10⁹, it may not provide adequate ESD protection over a long period of time.)

One Megohm: "One Meg" equals 1 million ohms or 1.0 x 10⁶. The exponent, 6, refers to the number of zeros after the 1. This measure is generally considered the maximum electrical resistance level for a conductive flooring specification.

25,00 Ohms: This is represented by the scientific notation 2.5 x 10⁴, or 2.5 x 10,000 ohms. This is the lowest end of the conductivity range. Anything lower than this range is considered an electrical shock hazard.

Path to Ground: The electrical link between a conductive material and the earth. Electrical conduit is an example of path to ground; the neutral or “green wire” is attached to the conduit and discharges electricity safely to the earth through the metal housing and the pipes, encapsulating the “hot wires.” A carpet must contain conductive fibers with external conductivity in order to be attached to a path to ground. Conductive carpet finds a path to ground from the combination of 1) conductive fibers; 2) conductive backing; 3) conductive adhesive; 4) copper grounding strip attached to conduit or building steel. A breach or omission in any of these four mechanisms will result in an open circuit and no path to ground.

Personnel Grounding Device: An electrostatic discharge protective device designed to ground any electrostatic charge accumulated on a person.

Point-To-Point Resistance: The resistance in ohms measured between two electrodes placed on any surface.

Resistance Range: User-specified upper and lower resistance values which define the user-acceptable resistance values of a wrist strap or wrist strap system.

Resistance To Ground: The resistance in ohms measured between a single electrode placed on a surface and ground.

Resistance To Groundable Point: The resistance in ohms measured between a single electrode placed on a surface and a groundable point.

Rtg: This is the abbreviation of resistance to ground.

Rtt: This is the abbreviation of resistance across the surface at two points.