Three panel image with various photos of a completed GroundLock Extreme interlocking ESD flooring installations
GroundLock Extreme Interlocking tile installed at a major cable communications/internet provider

What is the Best Antistatic Flooring Option for IDF Rooms, Data Centers and Server Rooms?

Multiple factors are at play

When choosing static-control flooring for an IDF room, data center or server room, multiple factors influence success and failure. Asking key questions – such as, what type of footwear will be worn in the space? Will people access open circuitry? Will you use static-free seating – help to determine the optimal floor, so you make the most of your investment.

In typical data centers, footwear is not – or usually not – controlled. The most common types of footwear used in workplaces that do not require static-control footwear are athletic shoes and casual footwear, such as boat shoes and loafers. Some ESD flooring materials, particularly those made with resinous polymers or plasticizers – ESD epoxy and vinyl, for instance – provide maximum benefit when used in conjunction with controlled ESD-protective footwear. When people wear regular street shoes, these floors can generate charges as people walk on the floor.

For optimal performance in spaces where people will not wear special ESD-protective footwear, it is crucial to select a floor, such as conductive rubber or static-dissipative carpet, for example, that inhibits static generation regardless of the type of footwear people wear in the space.

Another example: energy costs are notoriously high in data centers. According to a landmark ASHRAE-funded study*, the right ESD floor can help lower energy costs. This is because, selected properly, ESD flooring reduces reliance on humidification, sometimes used for static protection.

  • Link to ASHRAE study below

When selecting an ESD floor, always consider the circumstances you anticipate as standard operating procedure in your data center. Approaching the selection process this way enables you to inhibit static generation on anyone, anytime, regardless of humidity, the sensitivity of your systems or the application and critical nature of the equipment to your mission or operation.

Generally speaking, the effectiveness of static-control flooring is based on:

  1. A floor’s ability to inhibit static regardless of traffic, maintenance, humidity or footwear worn by people occupying the space. This is called preventing body voltage generation and is measured by The Walking Test. Body voltage generation is measured using test methods ANSI/ESD S97.2 or AATCC 134. The test results appear in volts generated when a person walks on the floor. Measurements should be taken with and without static-control footwear to account for real-world situations.
  1. The intrinsic ability of the flooring system to be grounded. This is also called finding a traceable “ground path.”

    This property is measured using test method ASTM F150. Test results should be obtained on material samples that have been preconditioned at humidity levels below 20%. According to IBM, a data center floor should measure above 150,000 ohms and always below 1.0 x 10E9 ohms using this test.

How ESD Flooring Works

Illustration demonstrating how charges are grounded with ESD carpet. A person (cropped to show legs/feet) stands on a carpet tile. A zoomed-in close up shows the carpet tile and backing. Underneath the tile is a layer of conductive adhesive and then the floor. The diagram shows the path to ground for the charge from the person. The illustration shows how conductive carpet fibers sweep static from shoe soles and transport charges to the underlying ground plane (conductive adhesive or underlayment).

An ESD floor draws static charges away from the body and pulls charges through the thickness of the floor. Charges then move across a conductive underlayment (often conductive adhesive) to a copper grounding strip to earth ground.

Recommended

Recommended floors are not listed in any hierarchical order. The best floor for the space depends upon the specific environmental and physical concerns along with architectural and/or owner objectives.

ESD Coating

Groundworx Ultra generation 3 ESD urethane installed over concrete

Installed cost: $$

  • High PSI rating enables easy rolling of large systems, pallet jacks and fork lifts.
  • Non-porous surface is easily cleaned.
  • Topcoat serves, all in one, as a decorative layer and ground plane
  • Urethane is scratch resistant.
  • Available in multiple colors. May come in custom colors as well.

Disadvantages: Not feasible on raised panels, Does not attenuate sound.

Due to cure time, best to install during initial construction vs in operational space.

ESD Carpet Tile

ShadowFX static-dissipative carpet tile

Installed cost: $$.

  • Easily installed over raised access panels or concrete.
  • Will not generate more than ASHRAE body voltage limit of 500 volts with ordinary footwear.
  • Significantly attenuates sound from cooling fans.
  • Can be installed as a floating floor without adhesive.

Disadvantage: Soft surface, difficult to roll heavy equipment

Completed ShadowFX static-dissipative (ESD) carpet tile installation in a data center.
Installation of ShadowFX static-dissipative carpet tile in a server room

Interlocking Conductive Tile With High Density Conductive Particle Distribution

StaticWorx GroundLock Extreme Interlocking (or Lay-flat) tile

Installed cost: $$$

  • Hard 2500 PSI surface enables easy rolling of heavy loads.
  • Available in attractive colors and patterns.
  • No ESD wax ever needed.
  • Can be installed over raised panels or bare concrete.
  • No adhesive needed.
  • Can be installed in fully operation spaces with zero shutdown.

Disadvantage: Expensive; best when used in conjunction with static-protective footwear

Conductive Solid Vinyl Tile With Vein Matrix

AmeriWorx ESD vinyl tile

Installed cost: $$$

  • Hard 2500 PSI surface enables easy rolling of heavy loads.
  • Available in attractive colors and patterns.
  • No ESD wax ever needed.
  • Can be installed over raised panels or bare concrete
  • Can be installed in operational spaces

Disadvantage: Best when used in conjunction with static-protective footwear

Image is split into three photos of completed AmeriWorx conductive vinyl tile installation in a manufacturing hub
Completed AmeriWorx ESD vinyl tile installation

Conductive Rubber

2-layer Eclipse (EC or GF) Rubber tile and sheet flooring.

Installed cost: $$$$

  • Best performing static mitigation surface in ASHRAE ESD flooring study.
  • Studies confirm EC rubber mitigates static on regular shoes as well as ESD footwear
  • Will not generate above ASHRAE body voltage limit of 500 volts with ordinary footwear.
  • Can be installed over raised access panel or bare concrete.
  • Can be installed in operational spaces
  • No ESD wax needed

Disadvantage: Initial cost

For optimal performance, static-control vinyl should be used in conjunction with ESD-protective footwear

Although static-control vinyl is a significant upgrade over traditional flooring, studies have shown that vinyl is less effective than rubber for static mitigation in environments where street shoes are typically worn.

Chart labelled “Comparison of Peak Walking Voltage”. Volts are shown for three different types of flooring - HPL, Conductive Vinyl and Conductive Rubber measured at 18 gr, 42 gr and 73 gr. Volts ranged from less than 10 to over 5,000.
Chart 1. Comparison of three (3) types of footwear on three (3) types of floor at three (3) environmental moisture levels – Peak walking voltage.

Above from: Footwear and flooring: charge generation in combination with a person as influenced by environmental moisture by D.E. Swenson : Affinity Static Control Consulting, LLC

Floors Not Recommended

Important Note: The objective of an ESD floor* in a data center is to mitigate static generation on personnel – regardless of humidity.  

* Also known as an antistatic floor or static-control floor

To varying degrees, all the following floors provide less effective ESD mitigation than the floors mentioned above:

  • Standard HPL
  • Static-dissipative vinyl
  • ESD polish
  • SDT vinyl floors that rely on waxes and polish
  • Low kV (also called computer grade) carpet
  • Conductive generation 2 epoxy

HPL

High pressure laminates are available in standard, static-dissipative and conductive grades. None of these 3 grades of HPL mitigates static on ordinary footwear. The ASHRAE flooring study results show that the conductive version allows charge generation above 1000 volts on personnel wearing ordinary footwear.

SDT Type Vinyl Tile (VCT)

SDT vinyl tile is a VCT product that requires polish or wax to maintain its dissipative properties. ESD floor finishes wear off and deteriorate significantly from ambient low humidity and traffic. To confirm that the wax continues to provide a dissipative surface, these polishes must be monitored, using measurement instruments, and wax/finish must be reapplied regularly when degradation is detected. SDT vinyl costs the same or more than floors with permanent static-control properties.

Static-dissipative vinyl tile and sheet floors

The ASHRAE study shows that some dissipative vinyl options are too resistant, and therefore provide inferior static protection on people wearing ordinary footwear. Floors measuring at the upper end of the static-dissipative range should be avoided. Even if they initially measure in the acceptable range, dirt or slight variations in the environment can render these floors ineffective or insulative.

The chart below shows the ideal range for flooring resistance when creating specifications.

A diagram showing a range in Ohms from 25,000 (2.5 x 10E4) (marked “absolute limit”) to 1,000,000,000 (1.0 x 10E9) (also marked “absolute limit”). A blue shaded area runs from 25,000 to 1,000,000 (1.0 x 10E7) and is labelled “Conductive range”. A gray shaded area runs from 1,000,000 to 1,000,000,000 and is labelled “Dissipative range”. On orange shaded area in the middle runs from 100,000 (1.0 x 10E5) to 100,000,000 (1.0 x 10E8) and is labeled “Ideal zone”. A red arrow extends out to the left of it with the text “Approaching too conductive 25,000 to 100,000) and another red arrow extends to out to the right with the text “Approaching too insulate 100,000,000 to 1,000,000,000).

Low kV Carpet Tile

Low kV carpet tile* is standard carpet. The term “low kV” is a misnomer often mistaken for the term static dissipative. Low kV carpet has high electrical resistance and cannot be grounded. Carpet designated as low kV prevents static shocks above 3500 volts. To put this in perspective, electronics used in data centers can be damaged by as little as 500 volts of static electricity.

Conductive Generation 2 Epoxy

Generation 2 epoxy floors rely on a buried ground plane for their conductivity. The top layer is actually a static generator with limited electrical conductivity. Although generation 2 epoxies often pass resistance testing, they generally fail walking body voltage tests. When a person walks on the floor, the static-generating top layer charges the person’s shoe soles . This technology is often marketed as multi-layer and usually includes a component called a “conductive primer.”

Image - labeled "Generation 2” with “Available in many colors” underneath - is a cross-section illustration showing how generation 2 ESD epoxy flooring works. The illustration shows feet on a flooring surface, labeled “topcoat”. The layer underneath is labeled “buried conductive ground plane”. The next layer is labeled “insulative primer/base coat” and a copper strip runs from the primer to ground (labeled “connect to AC or building ground”). The next layer is labeled “concrete subfloor”. The illustration shows the charge running from the person, across the surface of the floor, along the copper strip to ground. A zoomed in cross section shows the ground plane in detail and is labeled “Ground plane cross section: carbon fibers”. Text above the illustration reads “Electrically conductive fibers distributed throughout the topcoat allow charges to bleed from the surface to the buried conductive ground plane”

Checklist: Choosing the Right Static-control Flooring

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Background graphic is a still from the StaticWorx GroundSafe ESD Flooring – Your Trusted Partner explainer animation. In the foreground at the bottom are two boxes. The top is a bright blue with the StaticWorx logo and "GroundSafe ESD Flooring" underneath in white. The second is a dark blue-gray and includes the text in white: “GroundWorx ESD Flooring – Your Trusted Partner”

StaticWorx high-performance static-control floors protect electronic components, explosives, and high-speed computers from damage caused by static electricity. ESD flooring is part of a system. Choices should always be based on objective, researched evidence. When you partner with us, we look at all possible items that may need to integrate with the floor, and, focusing on your goals and objectives, help you find the right floor for your application.