Quite often we are confronted with a customer who wants antistatic flooring from us. However, we often find that almost no one knows exactly what to make of the term. On talking with the customer, we discover that what they actually need is something completely different. In most cases, customers need an ESD conductive floor to protect delicate electronic components. But let us explain in more detail.

Differences in standards

To get a better understanding of the issue, it is a good idea to start with the standards. These specify the requirements for each type of product placed on the market, or even for the area in question. It is not easy to find your way around them. There are many national and international standards, each requiring something different.

The basic standard defining product entry requirements for resilient floor coverings such as PVC flooring is International Standard EN 14041 – Resilient, textile and laminate floor coverings. This defines, among other things, two essential qualities a manufacturer must fulfil to define a floor in terms of ESD properties:

1. Antistatic properties
2. Electrical resistance

Antistatic properties

Antistatic properties are what ensure that the electrical charge on the human body generated when walking on such a floor will not exceed 2.0 kV. In practice, this means that a person walking on a PVC floor or carpet will not generate an electrical charge of more than 2,000 V. As you can imagine, there are two basic problems here in terms of protecting electrical components.

The first problem is that electrostatic charge is also generated during other human activities, such as walking on the floor. Just by getting up from an office chair, a worker can generate a charge of up to 18,000 volts. Handling a plastic bag can generate a charge of up to 17,000 volts. If a worker takes off a wool sweater in the winter, it can generate a charge of up to 25,000 volts. So it is by no means enough that the floor does not generate a charge. This may not be enough to protect your electrical components.

The second issue is that floors with electrostatic properties as defined by EN 14041 will prevent the human body from being charged to a charge higher than 2.0 kV. However, as we have written in previous articles, a 20 V charge can damage delicate electronics. Thus, when it comes to protecting delicate electrical components, it is not enough to consider a floor that meets the antistatic properties of this standard.

Electrical resistance

As you can see, the most important requirement for the flooring will be its electrical resistance, specifically that it be the lowest possible. This guarantees that the resulting charge is safely grounded. EN 14041 divides floors in terms of resistance into:

1. Floor coverings that dissipate electrical charge – those with a vertical resistance Rv < 1 × 109 Ω.
2. Conductive floor coverings – with vertical resistance Rv < 1 × 106 Ω.

Conductive floors, Dissipative floors, Floor types per EN 14041

Conductive floors, Dissipative floors, Floor types per EN 14041

Conductive or dissipative flooring?

As we have seen, dissipative floors can have resistances up to nearly 1 × 109 Ω. However, if you consider that the operator must wear ESD shoes (which also have some resistance), while the human body itself has its own electrical resistance, the total resistance of the “system” can be even higher. If you are working with delicate electronics, this resistance may be too high for safe discharge of the electrical charge.

What can we do?

So far we have only dealt with the properties defined by EN 14041, which sets out requirements for the floor as such. However, with regard to the protection of electrical components, it is equally important to consider EN 61340 – Protection of electronic devices from electrostatic phenomena. As we have written in previous articles, this standard defines requirements for the protection of delicate electrical components.

It requires a resistance to the grounding point of Rgp < 1 × 109 Ω. This is essentially the same requirement imposed by EN 14041. How to resolve this?

For protection of electrical components, what is more important is the system resistance, i.e., between person-shoe-floor. The standard specifies that system resistance measured per EN 61340-4-5 is Rg < 1 × 109 Ω while the voltage generated on the human body must be < 100 V.

It follows that if you have to achieve a system resistance lower than 1 ×109 Ω, the floor must have a resistance an order of magnitude lower. As indicated above, additional resistance created by footwear and the human body must also be taken into account. For safety reasons, it is therefore advisable that the flooring supplied to the systems be electrically conductive itself. This means that the vertical resistance of the floor Rv < 1 × 106 Ω.

System resistance (person–shoe–floor) measured per EN 61340-4-5.

Conductive flooring can effectively discharge the charge conducted through the human body and footwear to the grounding point of the system. This protects delicate electrical components and at the same time prevents the generation of electrical charge on the human body.

Summary – Antistatic or conductive flooring? 

We assume that the difference between antistatic flooring, dissipative flooring and conductive flooring is obvious to you by now. The antistatic floor only prevents the generation of a charge greater than 2 kV. However, this is entirely inadequate to protect the latest electrical components. A dissipative floor dissipates the electrical charge, but only a conductive floor ensures that it is effectively dissipated into the ground. So if you are thinking about minimizing the risk of electrostatic discharge, we recommend a conductive floor. It can most effectively eliminate the generation of electrical charge. And if you want to go even further, choose one that also guarantees a system resistance (person–footwear–floor) measured according to EN 61340-4-5 of less than 1 × 109 Ω. That way, you can be sure you’ve done your best when choosing a floor to protect your valuable equipment. 

Tip: Ask the manufacturer for a certificate from an independent testing organisation verifying that the floor meets specified parameters.

Contact our experts for more information, technical specifications or an individual offer. We are ready to help you find the best floor solution to meet the specific requirements of your industrial space.