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25 Feb

Building an Electrostatic Protected Area (EPA)

How to Build an Electrostatic Protected Area

Almost everyone’s familiar with the image of a white “cleanroom” or “bunny suit.” They show up in just about every depiction of people working in computer facilities in popular entertainment, and it’s a highly sought after specialty ‘armor’ in the video game Fallout 4.

What most people may not know is that the suits are designed not to protect the person inside, but the delicate circuitry they’re working on.  But not everyone who works with small, sensitive electronics needs to spend money for a full-on, disposable suit.

If you work with a lot of small electronics, a more affordable solution is to put together an electrostatic protected area (or EPA).  This doesn’t have to take up a lot of space and can actually be quite portable.  It just needs to be done properly.

Let’s start with the basics and work our way up to the safest and most expensive options.

Simple EPA

At a bare minimum, all personnel working within an EPA should have a personal grounding wrist strap.  These make sure any excess energy is grounded – forced away – from the electronic devices and circuit boards being handled.

Connected to that grounding strap is a dissipative mat. Dissipative means quite simply to disperse or disappear.  A properly designed and implemented dissipative mat does for the surface what the grounding wrist strap does for the person – protects sensitive electronics from electrical discharges.

Mats can be purchased pre-cut or in rolls, depending on what your needs are.

Attached to both of these is a common point cord, also referred to as a grounding cord.  These cords are fully insulated and take any electrostatic charges away from the person and the ESD mat to be grounded safely.

Often these simple options are packaged together as a field service or workstation kit that can be purchased as one unit to avoid forgetting any key elements.

Now that we’ve established the minimum requirements for an EPA, let’s look at additional options that can be easily implemented within your system to further insure the safety of the components and reduce the risk and excess cost of replacement.

From the Ground Up

For more permanent EPA installations, there are a variety of flooring options that can be integrated.  Everything from conductive and dissipative vinyl tiles to anti-static carpeting that can be utilized in the work area or just in the area surrounding your EPA system.  You can even add flooring with a high-end moisture barrier as well as anti-static protection.

Sole Protection

One of the most obvious ways we build up a potentially dangerous electrostatic discharge is just by walking.  Static charges build up naturally.  While a personal grounding wrist strap will help dissipate the charge, there are additional options for your feet.

Shoe covers with conductive strips are a quick, low cost addition to an existing EPA system and great for alleviating the risk of allowing visitors into the EPA area.

For employees whose duties mean they spend substantial time in the EPA area, you can add foot and heel grounders, toe grounders and sole grounders.

For even more protection, grounders can be upgraded to ESD shoes.  These come in a variety of styles for your business setting – even weatherproof boots and hiking models.

Additional Considerations

Adding isolation protocols and ESD protective containers can also complement your EPA system and reduce the chance of any accidental charges building up or discharging into your electronic components.

Of course grounding should be a consideration with any additions to your EPA system.  Whether it’s flooring or matting, grounding cords with a built in resistor add that much more protection to your area.  And the more working parts you have, the more grounding capability you require.

There are simple options to increase the grounding ability of any size EPA system, as well as monitors that can be added to the system – at the personal or system-wide level.

And if you really feel the need to cover yourself top to bottom, there are more workable clothing options as well.

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?

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.

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

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

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Static Dissipative shoe C4341

Static Dissipative shoe C4341

17 Mar

Should ESD shoes, heel grounders be worn outside?

Q: Is it ok to wear ESD shoes or heel, toe, or sole grounders outside?

A: No.  MIL-HDBK-263B Appendix 1 page 101 40.1.2 states, “Conductive shoes, shoe covers, or heel grounders should be used to discharge personnel on conductive floors. These items should only be worn in the ESD protected areas and should be kept clean so that contaminants do not inhibit their conductive interface with the floor.”

So, to protect your investment, for good house keeping and maintenance, longevity of the ESD personal equipment, just don them before going into the EPA and take them off when you leave.

Do this and keep them clean (vacuum inside of shoes weekly and maybe clean outsoles and grounders with soapy water once a week) and you’ll get more wear out of them and they’ll be more effective.

26 Jan

What is the importance of using ESD Footwear on ESD Floor?

Q. What is the importance of having the personnel within an EPA to wear ESD footwear on an ESD Flooring system?

A. Thanks for the inquiry. It was good speaking with you earlier. You had stated that you had concerns about the grounding of your flooring system and my first question to you was about the use of ESD footwear. I believe that you had stated that not everyone was using esd footwear.

You pose a situation here that needs to be addressed as a top priority at all levels of ESD Awareness for every client that we come into contact with. I don’t mean to over-simplify this but I am seeing a common trend in the ESD industry; your ESD system is only as strong as the weakest link in the chain. Another way to say this is; If you buy a Plasma TV, it needs to come with a power cord and you need to plug that in. Read More

05 Dec

What does ASTM F2413-05 compliant mean?

Q: What does ASTM F2413-05 compliant mean?

A: I’ve got the document from the American Society for Testing and Material Standards (ASTM) in front of me now.

They sent me a copyrighted document on June 2nd of 2005.

It’s significance and use section is pretty encompassing;

  1. This specification contains requirements to evaluate the performance of footwear for the following:
    1. Impact resistance for the toe area of footwear.
    2. Compression resistance for the toe area of footwear.
    3. Metatarsal protection that reduces the chance of injury to the metatarsal bones at the top of the foot.
    4. Conductive properties which reduce hazards that may result from static electricity buildup, and reduce the possibility of ignition of explosives and volatile chemicals.
    5. Electric shock resistance.
    6. Static Dissipative (SD) properties to reduce hazards due to excessively low footwear resistance that may exist where SD footwear is required.
    7. Puncture resistance of footwear bottoms.
    8. Chain saw cut resistance, and
    9. Dielectric insulation.

There’s a section in there that describes Performance Requirements and Workmanship, Hazard Assessment, Labeling and Identification, Marking and Compliance Requirements, and Keywords.