What are ESD Tile, Conductive Tile and Static Dissipative Tile ?

ESD Tile is ESD-safe floor tile for ESD Protected Area (EPA) per ESD S20.20 standard. There are two types of ESD Tiles, namely Conductive Tile and Static Dissipative Tile.

Maintenance Procedure For Conductive / Static Dissipative Tiles

Maintaining Conductive / Static Dissipative tiles is easy. Daily sweeping and damp moping with clean water is sufficient for most applications. Weekly wet mop with neutral detergent is good cleaning practice for Conductive / Static Dissipative Tiles. You might want to buff the Conductive / Dissipative tiles monthly or bi-monthly to remove stubborn dirt.

What is the difference between Conductive and Static Dissipative Tile ?

Both Conductive and Static Dissipative tiles are ESD Control floor tiles that meet ESDA S20.20 standard for ESD Protected Area to have floor resistance of less than 1.0 x 109 ohms. The difference between conductive and static dissipative tile lies in their respective electrical resistance. Conductive tile resistance range is from 2.5 x 104 to 1.0 x 106 ohms. Whereas most static dissipative tile has resistance ranging from 1.0 x 106 to 1.0 x 109 ohms although some static dissipative tile stays between 1.0 x 106 to 1.0 x 108. Compared to static dissipative tile, conductive tile has relatively lower resistance and more direct path to ground ; a fact that makes conductive tile of better ESD control performance than Static Dissipative tile.

Where Should Conductive Tile Be Used And Where Should Dissipative Tile Be Used ?

You can never go wrong by using conductive floor tile for ESD Control purpose although there is a perceived understanding that dissipative tile has its own advantageous value (see more explanation in next section of this technical notes). Because conductive tile has the least electrical resistance and best path to ground, it will also have the best decay time eliminating unwanted static charges. Conductive floor tile is recommended for IC chip manufacturing plant, semiconductors assembly and test facility, PCB / SMT processes, and other production areas where semi finished electronic products are exposed to risk of ESD damage. Conductive tile should also be used in any explosive arenas to prevent sparking due to ESD event. Dissipative floor tile on the other hand can be used in computer rooms, training areas, switching stations, finished electronic product packing area, pharmaceuticals and other areas where no semi finished electronic parts are exposed to ESD risk. Just remember, if conductive tile is specified by design team for a particular electronic device manufacturing process, do not try to break the rule.

Perceived Understanding About Static Dissipative Tile

Generally we tends to perceive static dissipative floor tile is safer to human than conductive tile when it comes to electrical shock hazard. In other words we tends to think that human exposed to electrical leakage has better chance of surviving on static dissipative tile which has higher electrical resistance than conductive tiles. However conductive tile has electrical resistance range that starts from 2.5 x 104 Ohm (not zero ohm) and according to NFPA 99 and UL779, this is good to be used as electrically-safe flooring for human.

In the past, the majority of companies selected their particular ESD control floors based on the misconception that static dissipative materials were safer than, while still equal in effectiveness to, conductive materials. This widespread fallacy led to the installation of millions of square feet of static dissipative flooring that may or may not meet the latest recommended range of less than 35 megohms for system resistance, as documented in ANSI/ESD-20.20-2007.

Is There Any Maintenance Procedure Difference For Conductive / Static Dissipative Floor Tiles ?

There is no difference in terms maintenance between conductive / dissipative tiles. Both need the same maintenance procedure.

Is There Any Cost Difference Between Conductive / Static Dissipative Tiles ?

With the latest tiles manufacturing technology, there is no cost difference between conductive tiles and static dissipative tiles. This means price for conductive and dissipative tiles are same.

How Do I Ground My Conductive / Static Dissipative Floor ?

Whether it is conductive or static dissipative floor, both should be grounded to a known earth ground. A known earth ground can either be earth of the electrical main service equipment or a dedicated ESD ground that is proven to be well grounded. Key consideration here should be to ensure all grounding systems (ESD ground, electrical ground, building earth ground) are of equal potential to prevent leakage current resulting from different potential at different grounding points.

Can conductive floor be used as means of ESD Control in working environment where technician without ESD Footwear were to handle PCB with ESD sensitive components?

All Conductive floor need to work together with ESD Footwear (eg. heel strap, ESD Shoes) for personnel grounding as means of ESD Control. However technicians without ESD footwear could still safely handle ESD sensitive components if they were wearing wrist strap. If you could ensure technicians were to wear wrist strap every time they handle ESD sensitive devices, you actually do not need to install conductive floor for cost saving purposes. However if you do decide to install conductive floor and at the same time have your technician wearing ESD footwear then you have the advantage of allowing technician to freely move around the conductive floor while he/she handles ESD sensitive devices without wearing wrist strap (remember wrist strap restrict technician's movement as he/she is "tied-up" by the wrist strap cord).