Lab Planning 101: The Complete Guide to Electrostatic Dissipative Flooring
For spaces with custom and/or intricate designs, keep in mind that copper grounding strips need to connect all ESD flooring pieces. An ESD flooring is only as effective as its installation. All images: Courtesy of Tarkett
We’ve likely all experienced it: after walking across a carpeted room, you touch someone and—zap! A small electrostatic charge shocks you. The human body can feel an electrical charge at 3.5kV, meaning that little zap had at least 3,500 volts of energy behind it.
While those 3,500 volts may not have felt like much to you, it can take just five to 10 volts to damage electronic equipment. It’s easy to see, then, just how important it is to consider electrostatic dissipation when designing spaces that will contain sensitive equipment. As a surface that essentially connects everything within a room, flooring is an especially critical component to electrostatic-sensitive designs.
All floors will generate electrostatic energy with foot traffic. Labs with electrostatic-sensitive devices will likely require what’s often called electrostatic dissipative (ESD) flooring. We’ll dive deeper into this in a bit—but first, let’s take a step back to fully understand static electricity.
How does static electricity form?
Static electricity starts at the subatomic level. All matter in this world is made of atoms, which contain protons, neutrons, and electrons. Atoms normally have an equal number of protons (positively charged ions) and electrons (negatively charged ions), but when two materials rub together—like feet walking across a floor—electrons jump from one atom to another, causing an imbalance of the positive and negative charges. This imbalance is ultimately what causes static electricity. Those surplus electrons will naturally release themselves in the form of current when coming into contact with something that is more positively charged—like when you touch someone after walking across the floor.
How does ESD flooring work?
ESD flooring is more than just a floor—it’s a complete system that works to direct electrostatic energy to a ground source. ESD floor systems comprise of a tile or sheet flooring product that contains a conductive material such as carbon, installed with a conductive adhesive and applied over copper ground strips that are connected directly to the ground source. Electrons flow through the flooring to the conductive adhesive and copper grounding strips, which neutralize the possibility of static build-up and safely dispel electrostatic charges to ground.
The ideal electrical resistance range for most ESD flooring requirements falls between 10^5 and 10^8 ohms. In general, ESD floors within this range are sufficient for electronics labs, server rooms, and MRI rooms.
Keep in mind that the copper grounding strips need to connect all flooring pieces. This is especially important if you’re considering designing a space with custom and/or intricate designs. An ESD flooring system is only as effective as its installation.
It’s worth noting, too, that footwear can affect the performance of the floor. Depending on how sensitive the room’s devices are, occupants may need to wear ESD footwear or ground straps.
What kind of ESD flooring do I need?
Not all ESD floors are created the same. Different floors and designs have different levels of electrical resistance, measured in ohms. Ohms essentially measure how quickly the floor will dissipate electrons to ground.
There are two categories of ESD flooring, static dissipative and static conductive. Static dissipative flooring requires a resistance range between 10^6 to 10^9 ohms. Spaces that are hyper-sensitive to electric charges may require electrostatic conductive flooring, which ranges from 25,000 to 10^6 ohms. Electrostatic conductive flooring functions much in the same way as static dissipative flooring, but it has a lower resistance, meaning any charges can flow (and dispel) faster. The ideal range for most ESD flooring requirements fall between 10^5 and 10^8 ohms. In general, ESD floors within this range are sufficient for electronics labs, server rooms, and MRI rooms.
Exact specifications range across industries. A brief overview of industry standards is included below, but keep in mind that these tend to be broad requirements; the exact needs of your space may be more demanding than what is specified here:
ANSI/ESD S20.20 for electronics manufacturing and handling addresses only the upper limits of resistance, requiring a floor’s resistance to be less than 10^9 ohms.
FAA 019f from the Federal Aviation Administration requires a resistance range of 10^6 to 10^9.
Motorola R56 for communications sites requires a resistance range of 10^6 to 10^9.
ATIS-0600321, which was developed for electrical protection of network operator equipment, requires a resistance range of 10^6 to 10^10.
DOD 4145.26-M from the Department of Defense specifies that “conductive tabletops, floors, and shoes for grounding personnel at operations involving exposed explosives with electrostatic sensitivity of 0.1 J or less.”
UFGS–09 62 38—which is shared by the US Army Corps of Engineers, the Naval Facilities Engineering Command, the Air Force Civil Engineer Support Agency, the Air Force Center for Engineering and the Environment, and NASA—details the specifications for a variety of flooring materials.
It can take just five to 10 volts to damage electronic equipment. Flooring, as a surface that essentially connects everything within a room, is an especially critical component to electrostatic-sensitive designs.
Knowing which flooring is best for your space ultimately comes down to how much voltage the equipment in the room can handle. To be certain an ESD flooring will perform adequately for your space, consult equipment manufacturer guides and the floor’s electrostatic testing specifications.
How do I maintain an ESD floor?
For the most part, maintaining an ESD floor follows the same process and guidelines as regular floors. It’s important to keep the floors clean to ensure optimal performance. When installed and maintained properly, an ESD flooring should last for twenty or more years. Regular testing with an ohmmeter will tell you how well the floors are performing. (Again, refer to equipment manufacturer guides to ensure the floors are within the recommended electrical resistance range.)
If you intend to put a finish over the floor, make sure it’s an ESD finish. However, there are some ESD floors that require no finish at all. These no-finish floors can be continually restored with simple dry-buffing, requiring less maintenance and saving on labor costs over the long-run. Plus, eliminating the need for harsh chemicals ensures better indoor air quality within the lab.
The final checklist
When installed and maintained properly, an ESD flooring should last for 20 years or more. And maintenance doesn’t have to be difficult—there are some no-finish ESD floors that can be continually restored with simple dry-buffing, requiring less maintenance and saving on labor costs over the long-run.
Now that you have a better understanding of how static electricity forms, how it can affect your equipment, and how the right flooring can help prevent those issues, you have a strong foundation for planning your lab. If you’ve determined that your lab requires ESD flooring, keep the following checklist handy for quick reference throughout your design and planning stages:
Consult any relevant industry specifications for ESD flooring.
Check your equipment manufacturer guides for voltage limits.
Confirm the electrical resistance levels of the floors you’re considering and speak with one of the flooring manufacturer’s technical support experts to be sure the floor will protect your equipment.
If applying a finish over the floor, make sure it is an ESD finish.
As needed, enforce a footwear/ground strap policy for anyone who will be occupying the lab.
Keep the floors clean for optimal performance.
Test the floor’s performance regularly with an ohmmeter.
*Author’s note: While ESD is being used to mean “electrostatic dissipative” throughout this article, it is also often used to mean “electrostatic discharge.”
