HP BL260c HP BladeSystem c-Class Site Planning Guide - Page 16

Smaller particles can pass through some filters, and over time, cause problems in mechanical parts. Selection of the appropriate filter media and maintaining the air conditioning system at a high static air pressure level can prevent small dust particles from entering the computer room. Other dust, metallic, conductive, abrasive, or microscopic particles can result from the following sources: • Subfloor shedding • Raised floor shedding • Ceiling tile shedding These particulates are not always visible to the naked eye. A good method to determine their possible presence is to check the underside of the tiles. The tile should be shiny, galvanized, and free from rust. To minimize dust and pollution in the computer room, observe the following guidelines: • Smoking-Establish a no-smoking policy. Cigarette smoke particles are eight times larger than the clearance between disk drive read/write heads and the disk surface. • Printer location-Locate printers and paper products in a separate room to eliminate paper particulate problems. • Eating or drinking-Establish a no-eating or drinking policy. Spilled liquids can cause short circuits in equipment such as keyboards. • Floor cleaning-Use a dust-absorbent cloth mop rather than a dry mop to clean tile floors. Special precautions are necessary if the computer room is near a source of air pollution. Some air pollutants, especially hydrogen sulfide (H2S), are not only highly toxic and unpleasant but corrosive as well. Hydrogen sulfide damages wiring and electronic equipment. The use of activated charcoal filters reduces this form of air pollution. Metallic particulate contamination Metallic particulates can be especially harmful around electronic equipment. This type of contamination can enter the data center environment from a variety of sources, including but not limited to raised floor tiles, worn air conditioning parts, heating ducts, rotor brushes in vacuum cleaners, or printer component wear. Because metallic particulates conduct electricity, they have an increased potential for creating short circuits in electronic equipment. This problem is exaggerated by the increasingly dense circuitry of electronic equipment. Over time, very fine whiskers of pure metal can form on electroplated zinc, cadmium, or tin surfaces. If these whiskers are disturbed, they may break off and become airborne, possibly causing failures or operational interruptions. For more than 50 years, the electronics industry has been aware of the relatively rare but possible threat posed by metallic particulate contamination. During recent years, a growing concern has developed in computer rooms where these conductive contaminants are formed on the bottom of some raised floor tiles. Although this problem is relatively rare, it may be an issue within your computer room. Because metallic contamination can cause permanent or intermittent failures on your electronic equipment, HP strongly recommends that your site be evaluated for metallic particulate contamination before installation of electronic equipment. Environmental requirements 16