What is the best antistatic flooring option for data centers and server rooms?

What is the best antistatic flooring option for data centers and server rooms?

Multiple factors are at play

Choosing static-control flooring for a data center involves a number of considerations. Multiple factors influence success and failure. What type of footwear will people wear while working in the space? Will personnel access open circuitry? What chairs will be used – static free or static generation?

Some ESD flooring materials made with resinous polymers or plasticizers – e.g. ESD epoxy and vinyl– provide maximum benefit when used in combination with controlled ESD-protective footwear. With regular street shoes, these floors can generate charges as people walk on the floor.

In typical data centers, footwear is not – or is usually not – controlled. For this reason it is crucial that you select a floor that will prevent static under 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 the equipment represents 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 the type of footwear worn by people occupying the space. This is called preventing body voltage generation aka The Walking Test. Body voltage generation is measured using test method ANSI/ESD S97.2. The test results appear in volts generated and should include measurements 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 ANSI/ESD STM7.1. Test results should be obtained on samples that have been preconditioned at humidity levels below 20%. An ideal data center floor will usually measure above 150,000 ohms and always below 1.0 X 10E9 ohms using this test.

    When testing ESD carpet, the test should be performed on new and used carpet to determine if traffic and abuse will degrade the groundable path.

Recommended

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

ESD COATING

Groundworx Ultra generation 3 ESD urethane

Installed cost: $

  • High PSI rating enables easy rolling of large systems, pallet jacks and fork lifts.
  • Non porous surface is easily cleaned.
  • Top coat provides decorative layer and ground plane all-in-one
  • Urethane is scratch resistant.
  • Available in multiple colors.

Disadvantages: 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: $$.

  • Can be installed with releasable adhesive 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

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.
  • Will not generate above ASHRAE body voltage limit of 500 volts with ordinary footwear.
  • Can be installed over raised access panel or bare concrete.
  • No ESD wax needed

Disadvantage: Initial cost

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

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

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 footwea

Static-control Vinyl performs best 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 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.  

To varying degrees, all of the following floors fail to prevent static generation in all environmental conditions:

HPL, Static dissipative vinyl, ESD polish and 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. Even the conductive version allows charge generation above 1000 volts on personnel wearing ordinary footwear.

SDT vinyl tile

SDT vinyl tile requires polish or wax which must be monitored with measurement instruments and regularly reapplied when degradation has been detected. These floors cost the same or more than floors with permanent static control properties. ESD floor finishes deteriorate significantly from ambient low humidity and traffic.

Static-dissipative vinyl tile and sheet floors

Static-dissipative vinyl tile and sheet floors are significant static generators when walked on with ordinary footwear. When a charged person or object moves across the floor, they fail to provide an acceptable decay time. Conductive casters on ESD chairs make poor electrical contact with these types of floors. Even when used with conductive footwear SD vinyl does not provide optimal static decay properties.

Low kV carpet tile

Low  kV carpet tile* does not mitigate or decay static at an acceptable level for use in equipment environments. Low kV carpet has high electrical resistance and cannot be grounded.

Conductive Generation 2 Epoxy.

These 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 generation tests due to the proclivity of the top layer to tribo-charge a person or mobile cart with casters. This technology is often marketed as multi-layer and usually includes a component called “conductive primer.”

Conductive floors with a low density distribution conductive granules.

Inadequate distribution of conductive contact points on the surface means these floors cannot provide a reliable ground connection for chairs, carts and machines with conductive casters.

Generally, due to the large contact area of the 5-pound NFPA test probes, these floors will pass a standard resistance test. Statistically, the probes are large enough to make some contact with conductive particles, masking their poor reliability with smaller objects such as chair castors.

These floors perform poorly in walking tests unless the test subject is wearing protective footwear with 100% conductive shoe soles.

CHECKLIST: CHOOSING THE RIGHT STATIC-CONTROL FLOORING

Play Video

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.

Play Video

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.