epa – Ground Zero Electrostatics Blog

28 Jul

5 Reasons Why Static Programs Fail

On May 6, 1937, the German passenger airship LZ 129 Hindenburg caught fire and was destroyed, killing 36 people in front of national news cameras and effectively ending the Zeppelin flying experiment.

The Hindenburg was larger than 4 Goodyear blimps combined, or about as long as 2/3 the height of the Empire State Building.

It was rainy that day, and the mooring ropes dragged along the ground as the airship came down to dock in Manchester Township. The prevailing theory is that the wet dragging ropes generated a static charge that traveled up them onto the ship.

There the charge ignited the Hydrogen fuel and… boom. Once considered the future of air travel, flying airships would not be utilized, either commercially or for military use until the end of World War II.

All caused by a single spark.

Much like the Hindenburg disaster, your company’s program to control electrostatic discharge (ESD) can be toppled with a few small errors that blossom into larger problems if they aren’t properly accounted and planned for.

So today, let’s look at the 5 common reasons why your static control programs could fail.

Sure! We have ESD Protocols, Right?

Most companies that deal with sensitive electronics and circuit boards also require that their vendors, third party suppliers, and subcontractors have an ESD program in place. Often even before signing a contract, an engineer is sent in to audit the ESD practices. And from time to time they will do spot-checks to verify that those practices are still in place.

Some companies, in an effort to hold on to their contract or cut expenses, will simply throw together a minimum program that can be audited. It’s done as inexpensively as possible and often doesn’t have any true protocols – training, preventative maintenance, and enforcement fall by the wayside.

You’d never do that, right? Well, except…

This is Gonna Cost How Much?

Top management are always looking at ways to work more economically. Unfortunately, if they are not properly briefed on the importance of proper ESD protection protocols, they may see many aspects of the ESD program as expensive and possibly unnecessary.

This isn’t their fault, they just need to be better educated. Which may be your job. The fact is, the expense for good, well-developed ESD protection protocols is dwarfed by the cost to replace or repair non-functioning components, not to mention the company’s reputation.

Excellent ESD companies are led from the top down, with company leadership not only showing financial support for ESD preventative programs, but also making time to attend training themselves, praise persons and departments with the best implementation, and allocate time and funds for ongoing training and improvement of existing programs.

Otherwise, you might end up in a pinch…

Here’s a Band-Aid for that Severed Limb!

You might have heard the old saw, ‘if there’s no time to do it right the first time, how are you going to find time to fix it later?’

Unfortunately, many companies appear to follow a different maxim – there’ll always be time to do it over.

Like our last reason, the problem is often financial. Momentary solutions that can be quickly applied to fix individual problems becomes the norm, despite the fact that the long term expense is much higher.

The best, most cost-effective solutions are applied right the first time and “solve” lots of problems by the fact that they prevent so many of them for happening. Then you don’t get into a situation where you’re spending a lot more to fix what could have been an easily avoided minor problem, but is now mission critical.

But that’s not going to help unless…

Training? We Don’t Need no Stinking Training!

Proper ESD prevention is a team effort, but many companies underestimate the size of the team involved. As mentioned before, upper level management should take an interest in training, and in fact, every employee should be given at least a rudimentary class or video in how to follow the company’s practices.

It’s not enough to train the engineers of you haven’t informed the janitorial staff that cleans their sensitive work areas after they leave for the day how to properly do so.

Secretaries, interns, sales people – everyone who has the potential to walk into or affect an Electrostatic Protection Area (EPA) needs to know how to properly behave to minimize risk.

And finally…

We Only Use the Best – the Best We Can Afford, That Is.

Yes, it keeps coming back to price. But price should not be the only factor in deciding who to buy your ESD supplies from. Not all companies are created equally. Not all ESD products are held to the highest standard.

You want to find a vendor that can supply your ESD needs who can guarantee all of their products are properly tested, meet or exceed industry standards, and have the certification to prove it.

Always be sure to properly vet your chosen vendor, making sure they meet these requirements and be willing to ask for clients you can speak to and recommendations you can verify. If they’re reputable, they’ll be more than willing to have you check them out with their existing happy clients.

ESD prevention is no casual task. Your company may not have the risk of ending 36 lives, but putting best practices into place can certainly save jobs, computers and your clients.

We’d love to be the experts you can count on for your full service, seamless ESD solutions. For more information or advice on your specific ESD prevention needs – or any other ESD questions, please contact us today.

07 Jul

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

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?

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.

07 Jul

Are ESD shoes and Conductive shoes the same thing?

Q:

Are ESD shoes and Conductive shoes the same thing?

A: There are two types of ESD shoes, Static Dissipative and Static Conductive.

The Static Conductive shoe will guarantee a combined resistance of personnel and footwear of less than 1.0E6 Ohms. I have a pair of Static Conductive shoes that when I’m standing on a static conductive flooring system (2.5E4 Ω to 1.0E6 Ω), my combined resistance from my body through the ESD footwear and through the ESD conductive flooring system to electrical ground or earth is less than 1.0E6 ohms per DoD 4145.26-M, C6.4.7.5.1: “The maximum resistance of a body, plus the resistance of conductive shoes, plus the resistance of the floor to the ground system shall not exceed 1,000,000 ohms total”… “The contractor can set the maximum resistance limits for the floor to the ground system and for the combined resistance of a person’s body plus the shoes, as long as the total resistance does not exceed 1,000,000 ohms.”

This Static Conductive shoe is typically used for electrical safety requirements for facilities that deal with explosive environments such as ordinance, munitions, explosive powders, flammable liquids, etc. This is outside of the realm of ANSI/ESD S20.20-2007 and MIL-HDBK-263B.

If you’re goal is the protection of static sensitive devices, then Static dissipative shoes on a static conductive flooring system or a static dissipative flooring system will suffice so long as the combined resistance of personnel, footwear, and flooring to electrical or earth ground is less than 3.5E7 Ω as per ANSI/ESD STM97.1-2006. In that case, a good static dissipative shoe will be more than 1.0E6 or a meg ohm, but the resistance will probably be less than 35 Meg ohms. The best way to measure the footwear is to have personnel wear them for at least 10 minutes prior to going to the tester and checking for pass/fail low/fail high, as that’s the most practical way to test them. You can measure the resistance of the shoe from insole to outsole, but they aren’t used that way on the ESD flooring system. The ESD shoe relies on sweat from the personnel that wears them.

My combined resistance from my body, through my Static Conductive C4327 (men’s) or C437 (woman’s) shoes and through a static conductive floor to electrical/earth ground is about 7.0E5 Ω. My combined resistance from my body through my Static Dissipative C4341 shoes and through a static conductive floor to electrical/earth ground is about 1.6E6 Ω.

I hope this answers your questions. Please comment.

…

Thank you very much, Pat

Static Conductive shoe C4327 Resistance per ANSI/ESD STM97.1-2006

0708090842

0708090845

Static Dissipative shoe C4341

03 Mar

Paperwork in the Electrostatic Discharge Protected Area (EPA)

Q: In our organization, there is a lot of paperwork that accompanies the product. Is this harmful to the product due to static generation? I have measured all the documents surface resistivity and find it to be dissipative in nature. Our production environment humidity is controlled from 40%-60%. I also tried to tribocharge the paper but there is no static voltage generated. The funny thing is when I rub my plastic comb and put it near bits of small paper, the bits get attracted to the comb. So is paper really harmful to the semiconductor products that we manufacture for our customer?

ESD Dissipative / Cleanroom Paper

A: Hello. It’s good for you to observe the possible generators of static in an EPA (Electrostatic Discharge Protected Area) and to remove all non-essential insulators and to ground conductors or soft ground them, as the case may be, and to use neutralization on isolated conductors and essential insulators (ionization). You may notice low static charge potential or voltage on that paper, but what happens when it tribocharges with other materials in the EPA? Read More →

19 Dec

Frequency of testing ESD Technical Elements in an EPA

Q: We have a number of carts, racks, and chairs in the clean room. When we do our weekly, monthly and semi-annual checks for ESD and grounding, do we do a statistical sample or do we check all of each item. Is there a standard that explains this?

A: You ask a very valid question and it just so happens that I received a similar question on this not long ago.

I wish there was one and only one ESD Bible that’s all inclusive and complete; from design to audit. The ESD Association has the ANSI/ESD S20.20-2007 document which gives us guidelines in establishing an ESD control program. But as far as a standard explaining when to audit each and every ESD technical element, I have yet to find a good source. The tables contained within 20.20 will give you “required limits” for various technical elements, but not a frequency of when to audit or test these systems. Between JEDEC Standard 625-A Table 2 of page 9 and other sources, I’ve put together these recommendations, but it’s up to you to implement them and tailor them to your unique processes; Read More →

05 Dec

Using an ESD Chair when already protected

Q: Is it necessary to use an ESD Chair when the humany body is already grounded through a Wrist Strap, Footwear or Heel Strap when working in an EPA?

A: I think it’s a great idea. I can be sitting at a workstation with an ESD flooring system, have a wrist strap on and when I get out of my chair, not generate more than 50 volts. I may not generate more than 5 volts. But what if I take my wrist strap off and jump out of my chair? I can easily generate 100’s of volts. Oh, by the way, jumping should not be allowed in an EPA. If you have great ESD shoes or sole grounders and you keep at least one foot firmly planted on the ground at all times, then maybe your ESD chair is redundant, but still an added piece to the chain in your EPA system.