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:
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.
Groundworx Ultra generation 3 ESD urethane
Installed cost: $
Disadvantages: does not attenuate sound, Due to cure time best to install during initial construction vs in operational space.
ShadowFX static-dissipative carpet tile
Installed cost: $$.
Disadvantage: Soft surface, difficult to roll heavy equipment
2-layer Eclipse (EC or GF) Rubber tile and sheet flooring.
Installed cost: $$$$
Disadvantage: Initial cost
Ameriworx ESD vinyl tile
Installed cost: $$$
Disadvantage: best when used in conjunction with static-protective footwear.
StaticWorx GroundLock Extreme Interlocking (or Lay-flat) tile
Installed cost: $$$$
Disadvantage: expensive, best when used in conjunction with static-protective footwea
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.
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.
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 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 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* 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.
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.