ESD Protection – Page 3 – Ground Zero Electrostatics Blog

12 Feb

ESD: Grounding, Isolation & Prevention

The Pilllars of ESD Protection

We’ve all had it happen. We’re opening our car door on a cold day, or we’ve just shuffled in our socks to the door and the moment we reach out, pop! A small snap of static electricity reminds us that we’re alive.

Think back to when you were a kid – your dad or uncle perhaps, showed you the power of static electricity by rubbing a balloon on your head and sticking it to the wall or causing your hair to rise up of its own accord. These tricks with static electricity are great for a chuckle or two. When you’re rubbing the balloon or your socks on the floor, it creates an imbalance of electrons, and that potential energy rests on your body or the surface of the balloon, waiting to discharge. Eventually it does and this sudden restoring of the electrons to their neutral state is called an electrostatic discharge or ESD.

That little tiny jolt of static electricity seems small but is really 3,000 volts – for humans, it’s the amperage that gets you. Unfortunately, for small electronics: circuit boards, semiconductors or even simple devices around the home, much smaller static discharges – ones too light to ever be sensed by our skin – can cause minor errors, or even completely destroy a device’s usefulness. In this situation, ESD is no laughing matter.

In a business—especially one that manufactures or handles a lot of electronics, but even in a typical office environment—this kind of damage can get expensive quickly.

So today, we’re going to talk about the three pillars of controlling ESD: Grounding, Isolation and Prevention.

Grounding

If you’ve worked with small electronics much at all, you’re probably aware that there are certain things you should do to prevent damage to that circuitry. You’re probably familiar with the third prong on many electrical cords. Just like the grounding plug diminishes the risk of you being electrocuted, grounding yourself and your work area keeps your circuit boards and electrical components safe by discharging any built up static electricity.

At a bare minimum, utilizing a grounding wrist band is extremely helpful. Many sellers include disposable bands when they ship electronic components, but we highly recommend owning and utilizing your own personal metal ground wrist strap that connects directly to your work surface with a personal ground cord. Always make sure the wrist strap is snug and is touching the skin to allow the charge to dissipate.

Isolation

Static charges cannot penetrate containers that are made of conductive materials or have a conductive layer. That’s why electronic components usually arrive in metallized shielding bags or a conductive tote box. Don’t forget you must ground them before opening. And don’t set these components just anywhere. What many people fail to realize is that simple items that can be found on any normal work surface – even an ESD mat – can also cause unnecessary static buildup that could lead to a fatal discharge.

Transparent tape, plastic sandwich bags, water bottles, Styrofoam coffee cups, even paperwork or blueprints can hold a static charge just waiting to wreak havoc on unsuspecting components. And even if you are properly grounded, holding the components too close to your clothing can also result in an ESD.

Prevention

Always take proper precautions when working on electronic components. Follow all of the tips above, and if you’re going to be working on several components or multiple projects, we recommend investing in some ESD bench and table matting for your work surface. It integrates well with a personal ground cord and wrist band and is the best solution for ESD prevention. A few dollars spent here as well as on ESD protective containers can mean plenty of money saved on ruined components as well as lost time while waiting for replacements.

Following these simple suggestions can mean a much safer environment for both you and your electronic components – and you can leave the static charge at home for parlor tricks.

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

07 Jan

Why Do You Need ESD Shoes?

You’ve heard teachers say, “Any question is a good question, so ask away!”

So, here’s a question…“Why Do I Need ESD Shoes?” Before we answer that, let’s briefly review electrostatic discharge first.

Electrostatic Discharge or ESD: A Quick Review

Simply defined, static electricity is an electrical charge caused by an imbalance of electrons on the surface of a material. This imbalance produces an electrical field that can be measured and that can influence other objects at a distance. Electrostatic Discharge (ESD) is the transfer of charges between bodies at different electrical potentials.

You are most likely aware of ESD at two extremes: the annoyance of that shock from striding across a carpet or witnessing the destructive nature of a lightning strike.

However, between these two extremes are electrostatic discharges found in workplace environments that can actually be costly or dangerous. Personnel shock injuries can range from a mild annoyance to a temporary loss of sight or hearing.

This same static discharge can ignite flammable mixtures and damage electronic components. Static electricity can also attract contaminants in clean environments or cause products to stick together. Sometimes called the “invisible enemy”, static electricity or ESD can wreak havoc in many work environments if not properly managed.

Why You Need ESD Shoes…

While there are physical and mechanical causes for ESD in manufacturing, technological or office environments, personnel are considered a primary cause of electrostatic discharge. In other words, personnel themselves charge up their own bodies! The clothing and shoes they wear generate electrostatic charges when they scoot in and out of their chairs, or as they shuffle across the floors. It can even be generated in unintentional movement as shirt fabric rubs up against the skin. (Talk about being charged up and ready to go!)

Combined with ESD flooring, you can prevent damaging buildup of static discharge with ESD shoes. Static dissipative footwear is designed to reduce the accumulation of excess static electricity by conducting the body charge to the ground, while maintaining a high enough level of electrical resistance.

Suggested industries that would benefit from ESD flooring and footwear include laboratories, clean rooms, hospitals, utility plants, high-tech manufacturing, car manufacturing and plastics, just to name a few.

What We Offer…

To offset potential damages from ESD, Ground Zero offers a variety of protective footwear:

Sporty: We offer a variety of high-quality conductive, static dissipative & regular athletic oxfords and sneakers. Models include steel toe and comfortable padding.
Casual: These casual shoes include conductive or static dissipative models for business casual or dressy environments. They feature steel toe design as well as comfortable padding.
Unisex: We also have formal or sporty styles for both men & women in slip-ons, clean room shoes or boat shoes.
Boots & Hikers: If you’re looking for work boots with weatherproof qualities, we have those, too!

Bottom Line: ESD Shoes will help the flow of electrons built up on the body choose a path to the ground rather than a destructive and potentially costly path toward your electronics or work environment!

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

17 Dec

Do You Need Static Control Flooring?

Does your business have a substantial investment in electronics or computers?

Have you ever experienced an unexplained failure? Perhaps one of your critical systems went down with no warning at a critical time (there’s never really a convenient time for that, is there?), or perhaps a component was working beautifully one minute and performing erratically the next.

One of the most nefarious—and hardest to detect— culprits behind failures of this kind is electrostatic discharge. By some estimates, it could be responsible for more than fifty percent of hardware failures, costing upwards of $5 billion each year.

So, if you have devices, people, and floors, then you face risks from the devastating effects of static electricity—specifically electrostatic discharge (ESD).

How Can Floors Protect Equipment from ESD Damage?

Since static control flooring provides an attractive “escape route” for static electricity that builds up in the most common of circumstances, it can be a relatively simple and inexpensive way to protect your valuable data & devices from getting zapped.

Aren’t specialized static control floors ugly?

If the thought of specialized protective flooring conjures up images of server rooms, data centers, or ugly hospital wards, then we’ve got good news!

Today, ESD floors come in an amazing array of materials, styles, and colors. Sure… we install rubber floors. We epoxy concrete.

But we also have attractive broadloom carpet that provides decent ESD protection for your sensitive electronics in beautiful designs—so beautiful, in fact, that no one would ever suspect that the carpet is actually serving a valuable purpose beyond that of ordinary carpet!

In addition to broadloom carpet, we also carry carpet tiles and vinyl tiles and sheet flooring. Each is suitable for different situations, and they are available in configurations that provide varying degrees of protection depending upon your specific situation.

Which Static Control Floor is Right for You?

Whether you run a manufacturing facility or a cubicle farm, a call center or a clean room, the fantastic assortment of options available today means that you can find a flooring solution that meets your needs. Obviously, there are a number of factors involved in making the right decision.

Some of the considerations you’ll need to include in your decision-making process include:

Durability: Will the floor be in a high-traffic area? The volume of foot traffic will certainly affect how long your floor will last, and therefore should be considered as part of the overall cost of ownership.
Maintenance: Since your floor contains components—from conductive carpet fibers to embedded veins of specialized materials—to give static electricity a place to go, you’ll want to weigh out the maintenance needs of the flooring.
Static Control Performance: ESD flooring comes in various levels of effectiveness (measured by its “conductivity”). How conductive or dissipative your floor needs to be depends upon the nature of your equipment, the installation environment, and the nature of the usage.
Other Factors: Does the floor need to help absorb sound to help control the noise in the environment? Do you need slip protection? What chemicals might be spilled on your floor?

As you can see, the flooring choices available to you can be a bit of a dizzying maze. But there’s good news: we’re here to help you navigate! Reach out today, and let our team of experts help you find the most effective solution at the right budget to match your situation perfectly!

31 Aug

Common Sources of ESD Damage You May Have Overlooked

As we’ve talked about previously, often the sources of static electricity go completely unnoticed. This is because we humans can’t even detect a static charge until it gets up to about 3,000 volts. The problem is that sensitive electronics can be damaged by a charge down in the 100-volt range.

If you’re in the business of manufacturing printed circuit boards or other electronics, you already know how serious a problem electrostatic discharge in the work environment can be. But for the rest of us, we may not recognize just how big of a problem ESD can be, and how much it is affecting our critical devices.

Once you become aware, then you’ll want to start addressing the problem by setting up a static-free zone, or an ESD protected area (EPA).

One of the first and biggest areas that you’ll probably begin to address in more critical environments is the flooring itself. Putting in one of the many types of ESD floors will help carry static charges away to ground right through the floor, rather than allowing it to end up damaging your sensitive equipment.

Another method of controlling ESD involves using specially designed ESD shoes that will allow static charges to dissipate.

Using ESD flooring and ESD shoes addresses a major source of static discharge buildup.

But where else do static charges come from?

Believe it or not, the typical work environment is loaded with sources of static electricity. Here are some examples you may not have thought about:

a typical “scotch tape” dispenser: the tape itself builds up a static charge coming off the roll (which can be up to a few thousand volts!)and the dispenser is usually made up of insulating materials that can build up a charge
plastic baggies (for components) can have a few hundred to over 1,000 volts of static charge built up on them with simple handling.
plastic water bottles (or any plastic bottle containing liquid) can build up thousands of static volts of electricity
any other products made out of insulating, rather than conductive materials (plastic cups, bins, organizers, etc.)

As you can see, often the sources of static electricity are so close at hand, and so seemingly benign, that they’re very easy to miss.

What Can You Do About It?

Bringing static electricity under control at a given workstation can be accomplished using a few simple tools:

ESD work mats will carry the charge away from any conductive materials you set on them
ESD grounding straps or wrist straps allow the wearer to stay grounded at all times, preventing the buildup of a static charge on the human body
The use of monitors and meters will allow for quick and easy measurement of static buildup, which will help identify and eliminate sources of ESD before they become a problem

Need help setting up your ESD protected areas? Give us a call today, and one of our ESD control experts will be happy to provide all the help you may need!

07 Jul

Can we make our own ESD tools?

Q: Can we make our own ESD Tools?

A: Perhaps. Since common hand tools can be at risk of creating an ESD event via CDM, what do we do about it? I was able to treat the screw driver in my last installation with our ESD anti-stat chemical Shock Stop. We also have Ultra Spray which lasts for a good deal longer than gimmicky products on the market, which are probably based on a fabric softener.

Our industrial products mentioned above will last longer, but need to be re-applied depending on usage.

I was brainstorming and came up with a more permanent solution to the ESD Screw Driver. Pretty effective, huh?

1-measuring-resistance-of-non-esd-screw-driver3

2-esd-chemical-shock-stop

3-treating-non-esd-screw-driver-with-anti-stat-shock-stop

4-remeasuring-screw-driver-resistance

5-looking-for-a-more-permanent-esd-screw-driver

6-ground-zero-esd-modified-screw-driver

6.5 esd-modified

7-measuring-resistance-of-gz-esd-modified-sd

Until I can work out a deal with Western Forge in Colorado Springs (dreaming a bit here), ESD Finger Cots! Ground Zero ElectroStatics, Inc. has got them. We’ve also got GZ-Shock Stop and GZ Ultra Spray for industrial uses in the EPA.

www.gndzero.com

1-719-676-2548

Order a sample today.

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

18 Jun

We don't need no stinking wrist straps, do we?

Q: I have read the White Paper 1: A Case for Lowering Component Level HBM/MM ESD Specifications and Requirements and found the ESD Control Programs and Resulting Data (Chapter 1, Page 20-23) particularly interesting.

Assuming a production environment with ESD flooring, footwear (and clothing), by the time a person walks to a workstation and sits down, the voltage of this persons should not exceed 500V (or even 100V as seen in Figure 3). That would mean even a seated operator in this case would not need to wear wrist strap, that theory would be correct right? After sitting down and this person sits on a stool (feet off the floor) with resistance to floor < 1.0x10exp9ohms, any HBM risk would be further reduced wouldn’t it?

A: Hello ****. Nice try. Even if you have an ESD flooring system and even if you have ESD footwear and even if you have an ESD task chair with ESD casters or an ordinary task chair with an ESD chair cover (very effective as well), ESD smock on… you STILL have to wear the wrist strap when seated at an ESD workstation.

The only time, per ANSI/ESD S20.20-2007 page 4, 8.2 Personnel Grounding, that personnel in the EPA (ESD Protected Area) should be without a wrist strap is when doing standing or walking about operations, and then two conditions must be met;
· “When the total resistance of the system (from the person, through the footwear and flooring to the grounding / Equipotential bonding system) is less than 3.5E7 Ω…”
· “When the total resistance of the system (from the person, through the footwear and flooring to the grounding / Equipotential bonding system) is greater than 3.5E7 Ω and less than 1.0E9 Ω and the BVG is less than 100 v per 97.2…”

This is what is said about seated personnel:

“When personnel are seated at ESD protective workstations, they shall be connected to the grounding / Equipotential bonding system via a wrist strap system.”

Hope this helps. I guess you could say redundancy is good in the realm of ESD. It’s the weak link in the chain that will cause an ESD event. If someone lifts their ESD footwear from the ESD flooring system while seated, they can tribocharge to above 100 volts. It takes only 0.3 seconds of charge time to exceed 20.20 requirements. If personnel is seated and getting up to go to break, it seems best to stand up, remove the wrist strap from the wrist, carefully set it down and walk away from the ESD workstation. Worst case is to take the wrist strap off while still seated, set it down, put your hand on the ESD workstation and near ESDS devices, then stand up out of the task chair before leaving the work station. Under proper conditions and with good bench mats, clean ESD floors, ESD task chairs, etc. in place, no ESD event. The problem with ESD events is that we cannot see, hear, feel them.

The only alternative to not wearing a wrist strap while seated may be the used of a smock with a grounding coil cord attached to it. You can see the footnotes on the 20.20 document at the bottom of page 4 for further details.

We adhere to and meet or exceed requirements put forth in ANSI/ESD S20.20-2007 or IEC 61340-5-1, which assumes a target HBM of 100 volts and less.

16 Jun

How do we test ESD conductive or dissipative gloves?

Q: How do we test ESD conductive or dissipative gloves?

A: The glove industry offers gloves for the protection of ESD sensitive items by using materials that will provide specific measurable “intrinsic electrical resistance of gloves and finger cots” as per ANSI/ESD SP15.1-2005.

Some materials are being used which reduce the amount of charge generation “and/or have static dissipative properties to reduce charge accumulation”, such as Nitrile or vinyl. I would image cotton could be effective based on the layer of sweat on our skin. But if you require ESD gloves in the Static Conductive range, those would need to be specifically made for that purpose. I’m currently working on nailing down an exact value of what these gloves should read and how that affects the ESD testing of it and the closest I could find comes from a test fixture from Prostat called the CAFÉ, or Constant Area & Force Electrode. They recommend using 1.5 to 10 volts when the measurement of glove in combination with personnel through a wrist strap assembly without the 1 meg Ω resistor is less than 1 meg ohm. They use 10 volts between 1.0E6 Ω and 1.0E7 Ω. Then they use 100 volts for above that. This is fairly easy to do using a sophisticated megger like the 801 in manual mode, otherwise the mere testing of the glove per 15.1 could be a challenge.

Here’s what confuses about ANSI/ESD S20.20-2007 and -1999 …

What’s the range of the glove and finger cots? Only in 20.20-2007 Tables 1, 2, and 3 final column does it give us “Required Limits” to measure up against. So then what? Go to manufacturing specs. Some list a value, some don’t. Be careful how they’re categorized; anti-static (describes that it’s low charging but doesn’t really quantify a resistance range unless you’re talking about packaging), static dissipative (1.0E6 Ω to 1.0E9 Ω ??), and static conductive (less than 1.0E6 Ω but greater than what?? 1.0E4 Ω rings a bell, but I’d hope it’s not less than that.).

Ok, so for our Static Conductive or black finger cots, they measure between 1.0E6 Ω and 1.0E8 Ω per ASTM D257 and meet the static decay specs per MIL-STD-81705B from 5000 to less than 100 volts in less than 0.01 seconds.

So here’s the upshot; My improvisation in measuring ESD gloves and finger cots involves using the PFA-861-H Handle (see attached), a DUT (esd glove), and a wrist strap without the 1 meg ohm resistor for measurements known to be below about 1.0E7 Ω , I hook that up to my meg ohmmeter and see what I get (see attached photos).

wand wand-and-sd-glove wand-and-sc-glove

This ESD TR20.20-Handbook has a wealth, a plethora of information about ESD gloves and finger cots, such as referring to yet other standards such as ANSI/ESD STM11.11 Surface Resistance Measurement of Static Dissipative Planar Material , and let’s not forget ANSI/ESD STM11.12 Volume Resistance Measurement of Static Dissipative Planar Materials, oh, and of course ANSI/ESD STM11.13 Two-Point Resistance Measurement of Static Dissipative and Insulative (what the??) Material, then it goes on to tell us to use the CAFÉ method, which is specifically designed for resistance measurements at the thumb and fingertips, which can yield much lower results than those obtained by the above test BECAUSE THEY INVOLVE A REAL LIVE PERSON, THE WAY THEY ARE ACTUALLY USED IN PRACTICE! Oh, and they say you can only measure once due to a “person’s skin emissions”. Fair enough. Time to reorder?

So… If this info helps anybody, let me know and send over a comment.

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.

09 Apr

Where to place the strap on a heel or sole grounder

Q: Do the heel strap cords need to be placed inside the sock i.e. between skin and sock or can the cord be outside the sock i.e. between sock and shoe? Is this specified in any ESD documentation? If so, which standard?

A: I like this question because I used to always put the strap between my foot (skin) and the sock, aka stuff it into my sock and under my heel. I later came to find that this wasn’t necessary.

I don’t believe it’s mentioned in any ESDA standards, perhaps in ESD SP9.2-2003 Footwear-Foot Grounders Resistive. But Foot Grounders are checked on a combo tester hopefully before you enter the EPA and if you pass and get a green light, you’re good to go. I’m seeing instructions to say the strap is to go “inside the shoe or sock”, so…

MIL-HDBK-263B Section 40.1.1 Personnel ground strap on page 100 says, “Personnel handling ESDS items should wear a skin-contact wrist, leg or ankle ground strap.” So this would imply skin contact, but I found it’s not necessary. If personnel wears cotton socks, the sweat and salt in our body make ESD shoes work, so thusly, the strap can go outside the sock and on the shoe’s conductive insole. Be sure to lay the strap across the heel and not just across the arch if you do it this way.

So just put the strap between your sock and shoe insole and use your combo tester or test yourself from palm to earth ground and see that you’re reading less than 3.5E7 Ω per ANSI/ESD STM97.1-2006 Floor Materials and Footwear. If you feel more comfortable putting it between the sock and skin, that’s fine too.

I find it to be more comfortable, convenient, and hygenetically sound to place it between the sock and insole as well. If there’s any mention of this to this detail elsewhere, it’s unbeknownst to me.