Sometimes there is confusion between what is an anti static mat used for tables, and conductive mats that are used on floors. They are both ESD Mats, meaning that they prevent electrostatic discharge when grounded.
What is the main purpose of the anti static mat?
Static electrons can sit on the surface of insulating materials found in tables and floors, so we use ESD mats to cover these surfaces.
When we go to handle electronics we want to make sure tables and floors are not electrically isolated, but instead electrically bonded.
Bonding allows those static electrons to discharge from tables and floors into the ground beneath the building they are in. The most common way to “ground” tables and floors is to connect them to an electrical outlet.
These mats are normally used for covering tables, tray liner, or as “runner” for the length of the floor for an assembly line.
The borderline between conductive and static dissipative is 1 million ohms per square. This is also referred to as 1 meg ohm. It is 1 x 106 ohms / square.
The active ingredient used in mats to make them conductive is carbon. Since carbon is black you can easily distinguish its presence from static dissipative material in the mat.
The ANSI / ESD standard for measurement of table worksurfaces is ANSI / ESD S4.1 Worksurfaces- Resistance Measurements. It recommends that the static dissipative sides of anti static mats should measure no more than 1 x 109 ohms / square.
How Do I Set Up an ESD Mat?
ESD Mats used on top of tables or workstations are typically two-ply (meaning two-layer) rubber mats. (This is sometimes also called a “static dissipative mat”). It is comprised of two layers: a top static dissipative rubber layer and a bottom black carbon-loaded conductive scrim layer.
The top static dissipative layer captures static off tools and electronics laid on top of the mat, while a snap is attached through the top layer of the mat to make contact with the bottom conductive layer of the mat so that the mat can be connected to an electrical outlet by using grounding.
We recommend you have mats attached to the ground for every 5 feet of matting on either side of the ground point. They should not be grounded in series, i.e., “daisy-chained” together. Instead, directly connect the wires to a ground line in the electrical outlet.
How Do ESD Floor Mats work?
Conductive mats are black because they are infused with carbon. Carbon is conductive, and it is the active material in these mats that conducts static electricity to the ground.
They are typically used on floors as anti-fatigue or chair mats. They can also be used as a shelf liner for extremely sensitive electronics.
If your floor is not grounded you should consider using these types of mats in static prone areas. When used you should be wearing foot grounders. These electrically bond your lower body to the mat.