
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:
- 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.
- 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
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
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
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.
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
SDT Type Vinyl Tile (VCT)
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.
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.
- Historically, low kV carpet materials were created to prevent painful shocks when people walked on carpet. Today we call this standard carpet, but the KV rating is often misinterpreted as a metric signifying the carpet as static free. This carpet is shock free.
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.”
Checklist: Choosing the Right Static-control Flooring
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Only static-dissipative and conductive floors can be grounded.
- Standard (non-ESD) flooring installed with ground strips or conductive adhesive will not offer any static protection.
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Industry standards, such as IBM’s recommendations for data centers and server rooms, recommend that floors measure above 150,000 ohms (1.5 x 10E5) and less than 1,000,000,000 ohms (1.0 x 10E9).
- Most StaticWorx flooring options (See Recommended) meet this guideline.
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Any effective static-control floor can be verified with an ohm meter to determine the electrical resistance of the material.
- If the material does not pass the ohm meter test, it cannot be grounded. Not sure how to do this? Ask us about our StaticWorx GroundSafe® program.
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Static-dissipative and conductive floors should be inherently conductive.
- In most cases, an ESD floor should not require antistatic sprays or waxes to enhance or maintain electrical performance. Topical finishes wear off and degrade. The floor must be monitored closely to be sure it stays in compliance. Dissipative properties are more reliably achieved by the physical composition of the material - not by a maintenance additive or ongoing dependent process.
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The floor should reduce static electricity regardless of relative humidity.
- Ask the supplier specifically about performance in very dry conditions (See ASHRAE study).
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The floor must inhibit static buildup in real world conditions without special static-free shoes or shoe straps and eliminate static with special footwear.
- When in doubt, ask for independent test data verifying this property. It should be available.
- The data should be derived from installed floors and from low humidity lab tests of new flooring.
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Never assume that a shock-free environment means a static-free environment.
- A shock-free environment only means that static charges are below 3500 volts. ASHRAE has set 500 volts or .5kV as a limit for static buildup when accessing sensitive equipment.
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Do the homework up front.
- It is much more costly to remove an ineffective floor and replace it than to select and install the right floor the first time.
- Any mission-critical space is only as secure as its Achilles' heel.
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Prepare for tomorrow. Have a plan.
- Smaller means more sensitive! Transistors in the microelectronic devices inside data storage equipment are becoming more dense, smaller, faster and more sensitive. In the past 10 years, the industry has evolved from 14nm nodes to 10nm to 7nm to 5nm. Anticipation studies suggest the potential exists for 3nm and below.
As with any potential security breach, it is always best to plan ahead.
Resources
- The effect of humidity on static electricity induced reliability issues of ICT equipment in data centers - Motivation and setup of the study
- In Compliance Magazine: ESD Compliance in a Server Room
- Data Center Flooring: ESD Floors Save Money & Reduce Energy Consumption
- New Research on Humidity and its Impact on Electrostatic Discharge: Are Data Centers Drying Up?
- Dependence of ESD Charge Voltage on Humidity in Data Centers (Part 1 - Test Methods)
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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.