Questions And Answers

Each company’s ESD control program should meet ANSI/ESD S20.20 which allows significant flexibility. For example, it is not required for personnel to wear ESD smocks when handling ESD sensitive items

“The selection of specific ESD control procedures or materials is at the option of the ESD Control Program Plan preparer and should be based on risk assessment and the established electrostatic discharge sensitivities of parts, assemblies, and equipment.” [ANSI/ESD S20.20-2007 Annex B]

“An EPA [ESD protected area] shall be established wherever ESDS [ESD Sensitive] products are handled. However, there are many different ways to establish ESD controls within an EPA. Table 3 lists some optional ESD control items which can be used to control static electricity. For those ESD control items that are selected for use in the ESD Control Program, the required limits and test methods for that item becomes mandatory.” [ANSI/ESD S20.20-2007 section 8.3 ESD Protected Areas (EPAs)]

However, using ESD smocks should be considered as “[ESD] Garments are intended to attenuate electrostatic fields that may be present on personnel clothing. … While a person may be grounded using a wrist strap or other grounding methods, that does not mean that insulative clothing fabrics can dissipate a charge to that person's skin and then to ground. Personnel clothing usually is electrically separate or isolated from the body.” [ESD TR20.20-2008 section 5.3.13.1]

An ESD control program having “ESD shoes, floors are grounded and carts have chains, tables have ESD mats” may well be sufficient. But do note that personnel grounding must be via a wrist strap when the worker is seated. “When personnel are seated at ESD protective workstations, they shall be connected to the grounding / equipotential bonding system via a wrist strap system.” [ANSI/ESD S20.20-2007 section 8.2]