Video: Qualifying an ESD floor - Resistance and Charge Generation

Hi, I’m Dave Long from StaticWorx. Today we’re going to talk about qualifying ESD flooring.

This past September, In Compliance Magazine published our article on this topic and the reason we wrote the article is most people that we deal with – engineers, facility managers, architects – don’t realize that there’s actually a special process called qualifying an ESD floor. What I’m telling you is qualifying the floor is different than testing the floor. It’s different than verifying the floor.

In our industry we all try to meet a standard called ANSI 20.20 and ANSI 20.20 is a document that clearly states that before you install a static-control floor under laboratory conditions you need to perform certain tests and those tests should be done with environmental controls in place.

So there’s two tests. The first one is what we call the ohm meter test. Everyone’s familiar with this and in fact 10 years ago if you were doing qualification you would very likely get away possibly with only doing this test.

So all I’m gonna do is hit a button and that tells me what the electrical resistance of this conductive tile is. So typically when we go into a facility and we talk to people, they think that’s all they have to do. All that test does is tell you what the electrical resistive properties of the floor are and it doesn’t tell you anywhere near enough. So now with the 2014 version of ANSI 20.20 it’s a requirement in the lab to test the floor for walking body voltage using the specific type of footwear you plan to use in your facility.

So what are the footwear options? Here’s an ESD shoe. These black pads on here are conductive materials that are electrically connected to the inside of the shoe.

Here’s a heel strap. As you can see, the heel strap is on a regular ordinary sneaker and it’s only a small band of conductive material.

We’ve got cleanroom booties. This little tab goes inside your shoe. This allows the electricity – all of these actually do – on your body to be transferred from your skin to these conductive materials to the floor to ground.

The funny thing about it is you would assume that any of these ESD footwear options would work very well. They don’t. Certain floors do not perform very well for certain types of ESD footwear. In our article there’s a chart and one of the things we’ve done is we’ve actually taken third-party lab data, presented it, showing the reader what the charge generation is on the same floor using heel straps and ESD shoes.

Probably the most graphic example of why you need to understand this: one of the floors we tested was a conductive vinyl floor, so with the ohm meter it measured exactly where it was supposed to measure, in the conductive range in that particular case, but when we walked on it with an ESD heel strap, we measured 800 volts. The manufacturer claimed that this floor met ANSI 20.20. In fact, it’s in their warranty. What they left out is when they did the testing, they did it themselves, they did it at the wrong humidity, and they did it with ESD shoes. Well, if you’re going to use ESD shoes that might help a little bit but the problem we have is we want to know whether a floor will work under adverse circumstances. That means we want to know what’s going to happen when the humidity is low. We also want to know whether the floor is going to generate static electricity on the rest of the shoe.

So if I take this sneaker and I rub it on this carpet, I generate a static charge. What you’ll notice with the heel strap is there’s no static but for the rest of the shoe there is. One of the reasons heel straps are an important test, is we know that most of a standard shoe with a heel strap, most of that shoe is going to generate static electricity. The only part that’s going to prevent static electricity is this small band.

So if we can find a floor the works with heel straps and works with ESD shoes, we’ve got a floor that means we don’t have to worry about swapping what type of footwear we use in the future. If a visitor comes into our facility, we can hand them a set of heel straps and know that they can touch their product without damaging it. That’s a big deal.

So now you don’t have to put the floor in, only to find out that you have to spend $100 or more per employee in order to find a footwear option that will work for that floor.