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15 Jun

Conductive, Dissipative, or Anti-Static Flooring?

Conductive, Dissipative, or Anti-Static Flooring

You’re hard at work at your latest assignment. Your boss wants you to put together a complete plan for creating a large-scale electrostatic protection area (EPA) for a client who will be assembling various sensitive electronics and they want to avoid any risk of losing their investment due to electrostatic discharge (ESD).

You’ve selected the grounding cables, the workstations, the custom cut matting, containers and furniture, all designed to minimize or eliminate the slightest chance of ESD damage. But a curious thing happens when you research the proper flooring.

A simple Internet search for ESD flooring yields numerous options, more than you expect and you start to notice they all fall under 3 categories.  In an instant, you’re faced with a decision, just like the game show, “Let’s Make a Deal.”

Suddenly, Monty Hall (or Wayne Brady, the current host!) is staring at you, asking do you want to choose door number one, number two, or number three: conductive, dissipative, or anti-static? The clock is ticking… How do you decide?

Door #1

For starters, let’s eliminate one of your options. Much like the ‘ZONKS’ of the game show, ‘anti-static’ is a worthless term in your ESD vocabulary.  By strict definition, anti-static refers to a material that resists generating a charge.  At one time it did designate a level of resistance, but was so overused and misunderstood, the term was removed from the ANSI/ESD standards.

So likewise, eliminate the term ‘anti-static’ from your discussion.

Deciding between the other two doors requires a closer look at the specific needs of the area for which the flooring is intended.

We’ve talked in another article about Ohms (Ω) and how they are the unit of measurement for resistance to electrical current.

Door #2

Because of the size and scope of most areas where it is necessary, the most common form of ESD flooring is referred to as ‘Static Conductive.’ Conductive flooring is at the low end of the electrical resistance scale.

Conductive carpeting may even be laced with carbon lines or metallic yarn fibers to encourage the flow of electricity. Because of the low electrical resistance, electrons flow easily across and through the surface, and can be grounded safely and quickly. This carpeting or vinyl tile is laid down with a conductive adhesive and grounded through the use of conductive tape or copper strips that run to a common ground.

This type of flooring is also generally a little more cost-effective than a dissipative solution.

Door #3

On the higher end of the resistance scale falls ‘Static Dissipative’ flooring. The higher resistance of these materials keeps the electrical charge more under control as it slowly flows over the surface and into a ground. Dissipative flooring is much more common in shared office environments where everyday shoes are more common, as opposed to a location where every element, from furniture to footwear, is controlled.

In our example above, the client will be assembling sensitive electronics like circuit boards and such in a large-scale environment. In this instance, a vinyl tile, or a poured epoxy flooring with conductive properties would most likely be the best option.

In an office setting where a company has their own IT department that fixes and assembles computers within the same facility, a dissipative, static resilient tiled floor would be a better fit.

But the fact is, these are very simplified examples of the myriad of variables that you can encounter when selecting the proper ESD controlled flooring. Your best option is to talk to an expert.

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 flooring needs – or any other ESD questions, contact us today.

11 May

10 Common Terms in ESD & What They Mean

10 Common ESD Terms

In 1865, Lewis Carrol published Alice’s Adventures in Wonderland, at the time, a thinly veiled political commentary wrapped in a fictional form.

Who knew that 150 years later, the book would have spawned several movies, pop cultural references, and a Grace Slick song.

But the most enduring artifact of the novel in today’s world – possibly reinforced by its own self-reference in the Matrix films, is the term “Rabbit hole.” In Alice’s universe, it meant falling into a world of confusion. Today it means losing track of time as you plumb the depths of a topic.

In our effort to be a provider of full service ESD solutions, we give you… The ESD rabbit hole – 10 Common Terms in ESD and What They Mean…

10 Common ESD Terms

The obvious place to start is with the term itself: ESD

ESD stands for ElectroStatic Discharge, a specific type of Electrical Overstress (EOS), defined as the sudden flow of electricity between two electrically charged objects caused by an electrical short, insulation failure, or simple contact. This is most often observed as static electric shock.

Electrical Overstress (EOS) is the exposure of an item to a current or voltage beyond what it can handle. When we’re talking ESD, it’s not just a static shock – because of the nature of sensitive electronics, even just a tiny bit of energy generated by lifting your hand or sliding across a desk can be dangerous enough to damage a component while you’re working, which is shy we recommend common grounding.

Common Grounding is a grounded device where two or more conductors are bonded, or a system for connecting two or more grounding conductors to the same electrical potential. Think of it as a lightning rod for your workstation.

Triboelectric Charging is the generation of electrostatic charges when two materials make contact, or often are rubbed together, then separated. This is what most people call static cling. The polarity and strength of the charges produced differ according to the properties of the materials.

Surface Resistance is measured in Ohms, and tells you how easily an electrical charge can travel across a type of surface. It might be helpful to think in terms of a water pipe analogy. The higher the resistance, the narrower the pipe. In the ESD world, a surface is either conductive or dissipative.

Conductive – A surface is conductive when it has a low resistance, anywhere from no resistance at all, such as water or copper, to mid-level resistance. This would be the wider of the two water pipes.

Static Dissipative – A surface is dissipative when it has a higher resistance, anywhere from the top end of the conductive to so much resistance that only a tiny trickle of “water” comes through the pipe.

Degradation is static electricity damage that weakens an electronic device, while giving the appearance of operating within normal parameters. However, once degraded, a device may fail catastrophically at a later point or just not last as long as it should.

Catastrophic failure is static electricity damage to a device that causes it to cease to function. The device must be replaced.

Ionization is the process by which a neutral atom or molecule acquires either a positive or a negative charge.

To Neutralize is 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. The charges cancel each other out, leaving a zero charge on the item.

We would love to be your full service, seamless ESD solution provider. For a deeper explanation of any of these terms and how they affect your workplace,  contact us today for more information.

05 May

Why 3.5E7 Ohms limit for flooring/footwear?

Q: Does anybody know the reason behind the upper limit resistance (3,5×10E7Ohms)of a grounding system (personnel+conductive shoes+conductive flooring)? Why not 1×10E8Ohms?
We have tried many waxes and all of them either give an overall reading for the system that is barely, when it is, within the limits above (IEC 61340-5-1 Table 1 – Note 2.

A: That reading is for ANSI/ESD STM97.1-2006 Floor Materials and Footwear- Resistance Measurement in Combination with a person.

So make sure you’re measuring a clean spot on the floor, someone wearing good clean heel grounders, sole grounders, or static dissipative shoes with one probe from a megger in the palm of their hand to earth or machine ground and the voltage on the meter set for 100 volts, as the resistance is greater than 1.0E6 ohms. Now if they fail this test and are less than 1.0E9 ohms, then they pass if they generate less than 100 volts as per ANSI/ESD STM97.2-2006 Floor Materials and Footwear- Voltage Measurement in Combination with a person.

Sorry so long for the response time.

Q2: Many thanks for you help.
What you are actually saying, if I understand it correctly, is that “if the combined resistance of an operator wearing whatever shoes over a a conductive flooring is greater than 1 x 3,5E7Ohms he will generate more than 100 Volts” and
currently in many electronic plants static generation above 100 Volts is not tolerated.

A2: No, that’s not what I’m saying.  I’m saying, as per ANSI/ESD S20.20-2007, that if you fail the < 3.5E7 ohms test, you may pass the less than 100 volts test and still be compliant to 20.20
 
Look on table 2 of page 4 of 20.20 and you’ll see what I mean.
 
Let me know if that helps.

 

ADD: I guess what needs to be understood with 20.20-2007 is that the < 100 volts and the < 1.0E9 Ohms still stands as well.  But if you’re testing per 97.1 and you get >3.5E7 ohms, then you can still pass 20.20-2007 if you have < 1.0E9 ohms per 97.1 AND < 100 volts per 97.2.

If you go to the table 2 chart on page 4 of 20.20-2007, it makes more sense.