ESD Storage Containers

25 May

What Are the 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:

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.
Necessary non-conductors – certain circuit board materials, device packaging, etc. – cannot lose their electrostatic charge by being grounded and appropriate precautions must be implemented.
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.

18 May

Conductive vs. Dissipative Materials

In the mid-1820’s, Georg Ohm, a self-taught mathematician and physicist, began doing experiments in the newly discovered field of electromagnetism. Hoping to advance his stalled career, he used the work of Hans Christian Ørsted as a jumping off point, discovering an inverse mathematical relationship between current and resistance.

Georg Simon Ohm

Unfortunately, in an effort to make his theories more understandable to non-mathematicians, he managed to alienate the scientific community and his groundbreaking work went unrecognized for almost 15 years.

Today, he’s remembered by the law that bears his name and its legacy, the standardized unit by which we measure electrical resistance – the Ohm (Ω).

Electrical Resistance: The Water in Pipe Analogy

To put it simply, what Ohm had discovered, but failed to adequately communicate, is that electricity acts like water in a pipe. In this analogy, resistance tells us how wide or narrow the “pipe” transmitting the electricity is.

When two items touch each other, they create an electrostatic charge – one item is positively charged, and one negatively charged. When the items are separated, it creates a triboelectric effect – a buildup of potential energy which can result in an electrostatic discharge (ESD).

In our quest to prevent ESD, which can be damaging and potentially catastrophic to sensitive electronics and circuitry, there are several approaches that vary, depending on the situation.

To illustrate those, we go back to Ohm’s electrical “pipe.”

At the narrowest end of the pipe, we have insulative materials – wood, carpeting, plexiglass. Insulative materials prevent or severely limit the flow of electrons across their surface.

While it may seem that this is the highest and best protection, the opposite is actually true. Because insulative materials are self-contained, they do not ground – meaning the potential energy continues to build up without going anywhere, until it comes into contact with another object, at which point, the new item is bombarded with the electrostatic discharge.

At the widest end of the pipe, we find the conductive materials – copper, steel, water. Conductive materials offer almost no resistance to electrostatic discharge. The electrical charge moves quickly through the materials – too quickly, which can lead to significant problems, as well as safety hazards.

In between these two extremes are the two materials most often used for ESD storage containers, matting and flooring: static conductive and static dissipative.

Towards the wider end of our metaphorical pipe, we find static conductive materials. Because of the low electrical resistance, electrons flow easily across the surface, and can be grounded safely. Typically, static conductive materials are most often used for ESD flooring.

Towards the narrower end of the pipe we find static dissipative materials. The higher resistance of these materials keeps the electrical charge more under control as it slowly flows over the surface and into a ground. Static dissipative materials are much more commonly used for ESD prevention and can be found in table top mats, ESD shoes and some flooring.

For storage containers – boxes, bins & totes – both conductive and dissipative materials can be used, depending on individual needs. Just keep in mind that dissipative materials have a higher resistance than conductive materials.

For more information, or an even more technical discussion of the properties of ESD materials, contact us today. We would love to be your full service, seamless ESD solution provider.

04 May

Finding ESD Storage Solutions

There’s a classic scene that appears, with some variation, in every James Bond film. Bond gets assigned a new mission and he goes to see MI-6’s Quartermaster, or “Q.” Q gives Bond everything he needs to complete the mission, including a few items that seem unusual or out of place.

Of course, as Bond fans know, these elements will at some point be combined to facilitate a distraction so Bond can escape. And usually that distraction is a rather large explosion.

One wonders how he was transporting the items before so that they didn’t explode in his Armani suit.

Of course, in real life, when items combine, the result isn’t usually an explosion. Or is it?

As we’ve mentioned before, the amount of Electrostatic Discharge (ESD) required to cause significant damage to sensitive electronics is far below the threshold where a human being can feel it.

By the time our bodies create a static charge that we can feel, it’s somewhere between 3 & 17 times stronger than what most electronics can handle without suffering damage.

Even just the controlled blowing of air, like the old canned air computer dust removal techniques can cause static ESD build-up that can be transferred to your sensitive electronics. And that tiny electrostatic discharge can cause latent or catastrophic failure, costing you time and money.

We’ve discussed selecting the proper shielding bags in a previous post. Another important weapon in your Electrostatic Discharge defense arsenal is anti-static ESD storage containers.

ESD storage containers are typically made of a conductive material, such as polypropylene or high density polyethylene and provide an added layer of protection, shielding your work areas and personnel from the harmful effects of ESD.

The conductive material provides a barrier which these fields cannot penetrate and prevents the build-up of electrostatic charge. The bins, totes and miscellaneous storage containers come in both static dissipative and conductive. Both control a potential electrostatic discharge, one by resisting it, the other by neutralizing it.

Additionally, be on the lookout for non-ESD protected items that may stray into the Electrostatic Protected Area – transparent tape, plastic sandwich bags, water bottles, Styrofoam coffee cups, even just pieces of paper – can be the source of an uncontrolled electrostatic discharge.

Of course, all of these storage solutions should be used within the minimum guidelines of an Electrostatic Protection Area, that is, wrist straps, ESD mats and a common ground.

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