How to select an ESD control Floor suitable for your manufacturing facility
There are a few major points to consider when selecting an ESD control floor. The first and foremost is whether you want a conductive or static dissipative floor. Many manufacturers offer both options, with the dissipative floor being the lowest-cost option.
If you plan to use the floor as a primary ground for people and carts, a conductive floor would be the choice. ANSI/ESD S20.20 (S20.20) requires a system resistance of a person through the floor and to ground of less than 3.5 x 107 ohms (35 megohms) when you use the floor as the primary ground. Many dissipative floors have resistance ranges above 35 megohms before considering operator resistance. Static dissipative floors are usually effective for reducing the amount of charge generated on people and equipment, but may not efficiently drain the accumulated charge. S20.20 allows static dissipative floors as long as the resistance to ground from anywhere on the floor is less than 1 x 109 ohms and personnel do not generate greater than 100 volts using the ANSI/ESD S97.2 test method (Floor Materials and Footwear – Voltage Measurement in Combination with a Person).
Another factor to consider is the installation of the floor. Most ESD control manufacturers have a list of certified installers for their floors. The installers need to consider several factors that a general floor installer may not consider. For all new base floors and in particular, those at grade level, the installer needs to run a moisture content test. Excess moisture will cause considerable problems, such as bubbling of epoxy or poured floors, or loose tiles in the future if it is undetected before installation. Installing the conductive layer, or conductive adhesive in the case of tiles, is critical to ensure correct adhesion and electrical properties. When selecting a poured ESD control floor, the application of the top coat is extremely critical. The procedure for finishing the top coat ensures that the conductive elements make contact with the conductive layer to provide a path to the ground.
Do not try to reduce the cost of the flooring project by hiring a general floor installer not approved by the vendor. Another factor to consider is the floor performance when combined with the selected footwear. Some floors perform differently with different foot grounding products. ESD control shoes and foot grounders should be tested with the floor to ensure acceptable resistance readings. ANSI/ESD STM97.1 is a standard test method that describes how to verify the electrical resistance of personnel while using the footwear and flooring system.
Charge generation may be evaluated using ANSI/ESD STM 97.2. The latter method is needed, as mentioned above, to help qualify a floor system for use in an S20.20 program if the resistance to ground from a person is over 35 megohms.