In addition to the financial costs associated with ESD events mentioned
earlier, safety is another big concern. As noted, most electrostatic charges
are harmless, naturally dissipating into the atmosphere or through contact
with a grounded object. In fact, ESD events happen all the time but mostly go
unnoticed because human beings are unable to feel charges at a threshold of
3,000 volts or lower9.
However, when charges accumulate and rise above 3,000 volts, they can
become dangerous. A significant ESD event may cause a worker to recoil from the
shock, creating a potentially dangerous situation for workers in confined spaces
or near moving machinery. In fact, any ESD event greater than 80,000 volts can
generate sparks that can knock a person to the floor and cause injuries, and many
workplace fires, explosions, and injuries have been linked to a static spark ignition
of vapors, gases, and dust10. The National Safety Council notes that such high ESD
It is clear that ESD is a very real concern with potentially serious and costly
implications if left unchecked. Fortunately, there are a number of products available
on the market that can help ground electrostatic charges and create safer
working environments. These products range from antistatic wearables such as
wrist and heel straps, smocks and footwear, to ionizers, antistatic floor mats,
as well as specially-designed ESD flooring products, which we will explore in
greater detail next.
Disclaimer: It should be noted here that static electricity is a highly variable
phenomenon, and while a review of various ESD flooring solutions will be
Terms You Should Know
There is a virtual dictionary of terms related to electrostatic
charges and ESD. Here are a few you should be familiar with:
Antistatic agent—A substance that is part of or topically applied to
a material to render the material surface static dissipative or
less susceptible to triboelectric charging.
Antistatic—Usually refers to the property of a material that inhibits
triboelectric charging. Note: A material’s antistatic characteristic
is not necessarily co-relatable with its resistively or resistance.
Bipolar ionizer—A device that generates both positively and negatively
Conductive materials—A material that has a surface resistance
of less than 1 x 104 ohms or a volume resistance of less than
1 x 104 ohms.
Conductivity—(1) The ratio of the current per unit area (current
density) to the electric field in a material. Conductivity is
expressed in units of siemens/meter. (2) In non-technical usage,
the ability to conduct current.
Dissipative materials—A material that has a surface resistance
greater than or equal to 1 x 104 ohms but less than 1 x 1011
ohms or a volume resistance greater than or equal to 1 x 104
ohms but less than 1 x1011 ohms.
Discharge time—The time necessary for a voltage (due to an
electrostatic charge) to decay from an initial value to some
arbitrarily chosen final value.
Electrostatic charge—Electric charge at rest.
Electrostatic damage—Change to an item caused by an
electrostatic discharge that makes it fail to meet one or
more specified parameters.
Electrostatic discharge (ESD)—The rapid, spontaneous transfer
of electrostatic charge induced by a high electrostatic field.
ESD ground—The point, electrodes, bus bar, metal strips, or other
system of conductors that form a path from a statically charged
person or object to ground.
Insulative materials—A material that has a surface resistance or a
volume resistance equal to or greater than 1 x 1011 ohms.
Neutralize—To eliminate an electrostatic field by recombining
positive and negative charges, either by conducting the charge
to ground or by introducing an equal opposite charge.
Static control (or, electrostatic discharge control)—
1.adj. - Electrostatic discharge protective; 2.n. - Generic term
for measures taken to diminish the effects of electrostatic
Static control floor—A permanently installed floor material such
as tile, carpet, polymer, epoxy, or sheet flooring that dissipates
static charges by grounding personnel, equipment, or other
objects contacting the floor material or that controls the
generation and accumulation of static charges associated with
Static control floor finish—A non-permanent coating periodically
applied to existing floor surfaces that dissipates static charges by
grounding personnel, equipment, or other objects contacting the
floor finish or that controls the generation and accumulation of
static charges associated with floor materials.
Static control floor mat—A movable island of material placed over
existing flooring that dissipates static charges by grounding
personnel, equipment, or other objects contacting the floor
material or that controls the generation and accumulation of
static charges associated with the material.
Static control footwear—Coverings for the human foot that have
properties to dissipate static charge when used in conjunction
with a static control floor or floor surface as defined in a standard.
Static dissipative—A property of a material having a surface
resistivity of at least 1 x 105 ohms/square or 1 x 104 ohm-cm
volume resistivity but less than 1 x 1012 ohms/square surface
resistivity or 1 x 1011 ohm-cm volume resistivity.
Triboelectric charging—The generation of electrostatic charges
when two materials make contact or are rubbed together, then
separated. (See also Triboelectric series.
Wrist strap system—A wrist strap when properly worn by a person,
where the electrical path includes the person, the cuff, and the
SOURCE: REPRINTED WITH PERMISSION FROM THE ELEC TROS TATIC DISCHARGE ASSOCIATION.
FOR A COMPLE TE GLOSSARY OF TERMS, VISI T HT TP:// ESDSYSTEMS.DESCOINDUSTRIES.COM/
ESD has the potential to disrupt the normal operation of an
electronic system and cause equipment malfunction or failure, or
degrading or even destroying it in some cases.