Movement of people and materials in the work environment is frequently cited as a major source of static electricity. This routine movement, particularly the contact and separation of shoes with the floor, generates voltages on personnel as high as several thousand volts. Similarly, the movement of carts or other equipment will generate electrostatic charge.
Traditionally, wrist strap systems have been used to control static electricity on personnel. However, various types of floor materials are used as alternatives or supplements to the wrist strap systems. A floor provides a method of connecting a person to ground while they are standing and walking, as well as carts or other mobile equipment. Using a footwear/flooring system is one way to control voltage on people.
Floor coverings, mats, paints, and coatings help control static charge by providing a path of moderate electrical conductivity from the human body (or equipment) to ground. Generally, there is a conductive material—such as carbon, metal, or other additives—that electrically connects the surface of the floor material to an underlying substrate such as conductive adhesive. The floor material and in some cases the underlying conductive substrate is then connected to ground.
Floor materials are used in most functional areas, especially those requiring high employee mobility or in areas where wrist straps cannot be used. Some of these areas include; receiving and inspection, stores and warehouses, assembly, test and inspection, offices and laboratories, and cleanrooms.
Some areas may require special considerations when using floor materials. Warehouses require materials that will not be damaged by heavy traffic such as forklifts. Certain chemicals used in circuit board cleaning could damage some floor materials in areas where they are used.
Insufficient cleaning will reduce the wear life of the flooring and affect the resistance properties. The floor should be properly maintained. The amount of maintenance required is directly related to the amount and type of traffic and type of particulate deposited on the floor. Residue from cleaning products can add resistance to the flooring system. Manufacturer’s recommendations should be followed for proper floor care.