Contaminants that conduct electricity need to be reduced in data center environments.
Semiconductors and sensitive electronics used in current information technology equipment have allowed for the manufacture of very high density electronic circuitry. Although new technology allows for significant increases or capacity in a smaller physical space, it is susceptible to contamination, especially contamination particles that will conduct electricity. Since the early 1990s, it has been determined that data center environments may contain sources of conductive contamination. Contaminants include: carbon fibers, metallic debris such as aluminum, copper and steel filings from construction, and zinc whiskers from zinc-electroplated materials used in raised floor structures.
Although very small, and at times not easily seen without the visual aid of magnifying lenses, this type of contamination can have disastrous impact on equipment availability and reliability. Errors, component damage and equipment outages caused by conductive contamination can be difficult to diagnose. Failures may be at first attributed to other more common factors such as lightning events or electrical power quality or even just presumed to be defective parts.
The most common conductive contamination in raised-floor data centers is what is known as zinc whiskers. It is the most common because it is frequently found on the underside of certain types of access floor tiles. Typically, the wood core style floor tile has a flat steel bottom. The steel may be coated with zinc either by a hot-dip-galvanize process or by zinc electroplate. The zinc electroplate steel exhibits a phenomena that appears as whisker-like growths on the surface. These small particles of approximately 1-2 mm (.04-.08 in.) in length can break away from the surface and get pulled into the cooling air stream. Eventually they might be ingested by the equipment air, settle on a circuit board and create a problem. If you suspect that you may have this type of problem, contact your IBM® Service representative.
The following figure shows light reflection from zinc whiskers.
Subscribe to this information
