Options for installing ESD flooring in an existing operational facility withminimal impact on contamination and production.

MANY FACILITY PLANNERS, concerned about contamination or potential scheduling delays, once dismissed the thought of installing electrostatic discharge (ESD) safe tile in operational clean spaces. Rather than risk tearing their buildings apart and losing valuable production time, many companies chose alternative methods to ESD flooring to be ANSI/ESD S20.20-1999 compliant. ESD industry control practices may include the combination of wrist straps, grounding cords, floor mats and “Faraday Cage” material handling protocols. Until recently, installing a new ESD floor most often included the difficult taskof removing the old floor first.

Ripping up old flooring, grinding concrete, and pouring epoxies and leveling compounds in a functional cleanroom would be a production manager’s worst nightmare. As one defense electronics facility manager put it, “Even though we absolutely need a conductive floor in our cleanroom, we can’t afford contaminating our HVAC system with dust and odors from flooring installation processes like shotblasting, concrete repair and skim coating. We’d have to build a back-up cleanroom before we would even consider installing a newfloor.”

The alternative is a temporary production shutdown during flooring demolition and installation which may pose an even worse proposition. Horror stories abound about companies expecting a one week installation schedule for shutting down manufacturing and moving equipment into rented trailers, only to watch one week become 10, 15, and even 20 days. For these reasons, space planners with an eye on risk management are asking for installation methods that willneither disrupt production nor potentially corrupt their controlled environments.

Reasons for Installing ESD Flooring in Occupied Areas
Let us start with the reasons why a functioning cleanroom facility manager might want or need to replace a floor. Regardless of the issues involved, one does not replace an existing floor unless it is absolutely necessary. Floors are only replaced when the existing flooring, usually a seamless epoxy or tile, becomes incompatible with ongoing needs. In a cleanroom or cleanmanufacturing facility, there are four main reasons why this happens:

1) The existing floor, while conductive, may not meet increasingly stringent cleanroom criteria. Some PVC/vinyl tile is known for out-gassing and plasticizer migration. The material loss from the floor can contaminate electro-optics or giant magnetoresitive (GMR) head manufacturing processes (see Figure 1).

2) The existing flooring material is improperly bonded to the concrete and has become a safety or maintenance problem. This problem could be the result of any number of issues including vapor drive (commonly referred to as moisture problems), alkalinity from the concrete subflooring or poor installation of the original floor.