 |
 |
 |
 |
 |
 |
Zinc Whiskers: Could They Happen to You?
by J. Eric Smith
Zinc whiskers are not a new discovery. In fact, they were originally detected by the telephone industry in the 1940s. However, only recently has their impact on information systems been extensively noted.
Zinc whiskers grow on metal surfaces that have been galvanized, or electroplated with zinc for protection against corrosion. In computer rooms, the most common source of zinc whiskers is the underside of zinc-plated raised floor tiles, common to flooring installed in the 1960s-1980s.(1) Other sources include zinc-plated floor supports and rails, equipment racks and even hardware such as washers, screws and nuts.(2)
As zinc whiskers grow, they eventually break loose merely as a result of basic, daily activity. Once ‘on the loose’, they float freely and have the potential to become lodged in computer systems. Once inside the system, whiskers wreak havoc because zinc is a conductor of electricity.
The chief problem whiskers cause is an electrical short if they come into contact with exposed circuit cards. These shorts can lead to equipment failure with undeterminable system downtime. To complicate the hazard, identifying the whisker hazard can be arduous because the whiskers immediately disintegrate when the circuit is shorted.
UNISYS WORLD magazine reported that zinc whiskers took one of the largest geriatric care facilities in Canada one year and more than $100,000 in unbudgeted expenses and hundreds of hours in overtime to determine that they were the cause of server failure and other issues on their 50-server network. It turned out, that an interior construction project which included tearing up early ‘80’s flooring had released thousands of these zinc whiskers into the air.
According to the NASA Goddard Space Flight Center, zinc whiskers are so miniscule – often no bigger than a few millimeters in length and a few thousandths of a millimeter in diameter – that normal dust filters in computer equipment will not prevent them from breaching the system. Essentially, zinc whiskers are lurking and if the environment exists for them to grow, they will, unaffected by temperature or humidity.
Zinc whiskers not only have the potential to cause equipment failures, they are costly to identify and eliminate. Depending on the severity of the problem, hundreds of thousands of dollars can be spent on clean up alone that often involves complete replacement of floor tiles, equipment racks and other components.
Sources:
(1) “What nasty little things are lurking inside your data center?” (Unisys World Monthly, Nov. 2002)
(2) “Zinc Whiskers: Could Zinc Whiskers Be Impacting Your Electronics?” (NASA Goddard Space Flight Center)
|
|
