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07 Jul

Is Bare Concrete Really the Best “Anti-Static” Flooring?

Is Concrete Really Anti-Static?

There used to be an old wives’ tale that standing on bare concrete for too long caused varicose and spider veins.  In the 60’s, that idea was largely supplanted by the hippie movement that believed standing shoeless on bare concrete allowed the body to become more grounded.

Unfortunately, it seems that the once-held hippie belief has permeated into the world of electrostatic discharge (ESD) prevention.  But nothing could be further from the truth. Because while bare, unsealed concrete floors that are allowed to ‘breathe’ have anti-static tendencies, they are definitely NOT grounded.

Nothing to Cling To

While the lower expense of a bare concrete floor makes it appear like a desirable remedy, there are several reasons it is not classified as a true ESD flooring solution.

First there’s that word – tendencies. Bare concrete floors tend to be anti-static, but they are not reliably so. That’s because anti-static characteristics are not inherent in concrete like they are in a carbon-filled material or a poured ESD epoxy.

To further complicate the issue, the measure of how anti-static concrete is, is dependent on many variables – the most significant of which is its permeability to moisture. If you’ve explored our website at all, that should immediately raise a red flag.  In an earlier post, we talked about why moisture is the #1 enemy to your ESD flooring.

A Shift in Standards

If that doesn’t scare you away, we discussed in this post about how anti-static is not an adequate measure for ESD flooring. To summarize, the term “anti-static” refers to a material that resists generating a charge. And bare, sealed concrete does do that – most of the time. But over the past 30 years or so, ANSI and the ESD Association made the effort to remove the term from their professional industry standards because it was so overused and misunderstood.

Those standards are discussed in this post.

And for good measure, we discuss in another post the dangers of cutting corners to save money when building your ESD Protection Area (EPA). Some up front expenses are definitely worth the long-term benefits.

Fully Charged

So, let’s assume that the concrete floor you’ve just installed is as anti-static as it can get. You can walk across it to any other part of the room and there will be no static buildup, aka triboelectric effect.

But what happens when the CEO comes down to inspect the area, and as he’s walked from his office to the EPA area, he’s built up a static charge. It’s on his body, on his clothes; we know that even the slightest movement in a conductive area builds a charge that can damage sensitive electronics.

When he hits that concrete floor, the charge doesn’t just disappear. It stays with him. Because while concrete has the tendency to avoid building up a static charge, it does nothing to dissipate an existing charge. And this is the biggest problem with the use of concrete as an ESD floor. It cannot act as a ground.

The CEO touches a circuit board, it gets the electrostatic discharge, ruining it – and he blames you. And then you have to install a true ESD floor anyways. Why not just do it right the first time?

We would love to be your full service, seamless ESD solution provider.  Contact us today for more information.

25 May

What Are the Standards for Electrostatic Protection?

Standards for Electrostatic Protection

So, you’ve just been tasked with building or designing your first Electrostatic Protection Area (EPA). You’ve started doing your research, but there are so many choices, from so many different companies. Suppliers, manufacturers, third party providers… If only there was some established standard for judging the efficacy and reliability of all those pieces and parts.

Well, you’re in luck! In 2007, the American National Standards Institute (ANSI) in cooperation with ElectroStatic Discharge Association (ESDA) released a unified set of standards for the design, implementation and maintenance of ElectroStatic Discharge control programs.

In the midst of World War I, five engineering organizations recognized the need to develop standards that could eliminate confusion and could be adhered to across all disciplines, without regard to politics, profits or personal preferences. These groups reached out to the U.S. Departments of War, Navy, and Commerce to form an impartial third party non-profit organization, then known as the American Engineering Standards Committee.

Following the war, the organization spent the next 20 years establishing several safety protocols still observed today, like eye protection, hard hat standards and in-house electrical safety while at the same time reaching out to other similarly tasked international organizations.

When the United States entered World War II, the organization, which would eventually come to be known as ANSI, helped to accelerate the war effort and productivity, created more effective quality control measures, as well as helping to advance photography, radio, and even the development of Velcro.

In 1970’s, ANSI established a public review process and began the herculean effort of moving the United States to the metric system. While the general public never really connected with the metric system, the effort did bring ANSI to the forefront of private sector companies who discovered standardization was a way to stay more competitive in an increasingly global economy.

With the advancement of personal computers in the late 70’s and early 80’s, engineers at several companies recognized a need for more understanding of electrostatic discharge and its prevention. They formed the ESD Association, a non-profit, voluntary professional organization that for almost 35 years has sponsored educational programs and developed standards to help eliminate losses due to electrostatic discharges.

Together, leaning on the historical experience of both military and several commercial organizations, ANSI and ESDA developed the definitive standard for ESD protection, the very cleverly named ANSI/ESD S20.20-2007.

Covering about every conceivable area of ElectroStatic Discharge, the ANSI/ESD S20.20-2007 utilizes both the human body model and the machine model to provide a broad set of guidelines for ESD protection.

The Human Body Model is the military standard that defines and rates the vulnerability of an electronic device to the ESD generated by a human being touching it. The Machine Model works similarly, except it rates the vulnerability of a device receiving a machine discharge into ground. It was originally developed by car manufacturers as their plants moved to more mechanized production technology.  The Human Body Model is about 10 times more sensitive than the Machine Model.

There is a lot to explore in the ANSI/ESD S20.20-2007 guidelines, but for the purpose of this primer, the document highlights 3 fundamental ESD control principles:

  1. All conductors should be grounded. This includes the personnel and the surfaces they are working on.  We recommend, at a minimum, personal grounding wrist straps, ESD table or bench mats, and a common ground cord.
  2. Necessary non-conductors – certain circuit board materials, device packaging, etc. – cannot lose their electrostatic charge by being grounded and appropriate precautions must be implemented.
  3. Static protective materials, such as ESD shielding bags or ESD totes and boxes must be utilized when transporting sensitive electronics outside a properly prepared EPA.

There are slightly less stringent standards that apply to floors and bench mats, but ANSI/ESD S20.20-2007 is the highest and most comprehensive guideline so far. So when you’re shopping for the parts needed to establish your EPA area, always look for companies that maintain that standard in their products and services.

We would love to be your full service, seamless ESD solution provider; contact us today for more information.

05 Dec

ESDA Specifications

Q: May I know the standard test procedures and parameters (ie: surface resistivity/surface to or person to ground resistance, decay time or any other parameter if applicable) and recommended values for confirming the worthiness of the following ESD items?

  1. ALL ESD PACKAGING ITEM
  2. ESD FLOOR AND WORK SURFACES
  3. ESD CLOTHINGS
  4. ESD FOOT WEARS
  5. ESD HANDLING ITEM viz., BRUSHES / BINS / PCB RACKS

A: Please consult your copy of ANSI/ESD S20.20-1999 from the ESDA at http://www.esda.org/.  It has specific documents for different technical elements.  For example, S1.1 for wrist straps, 2.1 for garments, 3.2 for ionization, 4.1 for worksurfaces-resistive characterization, 4.2 for worksurfaces- charge dissipation, 5.1 for Human Body Model, 5.2 for Machine Model, 5.3 for Charged Device Model, 6.1 for grounding, 7.1 for resistive characterization of materials-flooring materials, 8.1 for symbols-ESD awareness, 9.1 for footwear-resistive characterization, 10.1 automated handling, s11.11 surface resistance of static dissipative planar materials, 11.12 for EDS items-volume resistance of…, 11.2 for Triboelectric charge accumulation testing, 11.31 for bags, 12.1 for seating, 13.1 for electrical potential from soldering/desoldering hand tools, STM 97.1 for floor materials and footwear-resistance measurement in combination with a person, and STM 97.2 for floor materials and footwear-voltage measurement on a person just to name a few.

I could spend a lot of time digging up actual values for these specific items that we provide, but I haven’t put anything like that together all in one place.  I will work on that and perhaps we can post that info all in one place.  But keep in mind.  We do not determine the parameters, we merely work to comply with them.