The human body is the number one source of data center contamination. Dandruff, dead skin flakes, hair, body oils, makeup residue, bacteria and germs are just some of the many forms of contaminations humans introduce to data centers each time they enter.
Also from humans – sodium, potassium, chloride, and magnesium contamination can be introduced. An example would be the fact that a cigarette smoker releases airborne particles up to one half hour after smoking a single cigarette.
Soil transferred from outside environments: carpet fibers, dirt, bacteria and chemical residues from hallway and bathroom floors, food particles, and cleaning chemicals and finishes brought in on the soles of shoes and the wheels of carts, are also common sources of contamination.
Metallic particles: Worn air conditioning parts, metal shavings, electrical rewiring debris, raised floor tiles, heating ducts, vibrations from HVAC and computer units, printers, zinc whiskers, and friction from moving parts on equipment are all causes for metal particles to be released into the ambient air and subfloor plenum. If you picture the structure of your access floor system, it’s generally a metal-bottomed pan (or at least metal tile edge) sitting on a metal grid and pedestal system. The floor is under constant vibration caused by the computer cabinets and CRAC units. That vibration causes an eventual breakdown of the metal and releases tiny metal fragments into the subfloor plenum (often referred to as ferrous metals).
Biological: Water often accumulates in ductwork, CRAC unit drain pans, humidifiers, ceiling panels, insulation, and carpeting. The danger to this is that stagnant water leads to bacteria, viruses and mold. Another common contamination problem is the mixture of moisture in the CRAC units with metals and other contaminants in the air produce an alkaline build-up in the CRAC unit drain pans. These contaminants then become airborne through the normal operation of the CRAC unit itself. The result, if left untreated, is accelerated corrosion of pedestals, floor panel bottoms, grid pieces and metal cable trays.
Organic: Cardboard boxes, wood (pallets) items made of rubber, paper, elastomers and plastics are all sources of contamination. Products made from these materials have the natural property of “breaking down” and releasing themselves back into the air as tiny particles.
Raw Concrete Sub-floor Deck: This is a major source of contamination, and yet often the most overlooked. Raw concrete, like the other organic contaminants listed above, also has the property of “breaking down.” To illustrate this, if you have a raw concrete garage floor or patio at home and you can rub your hand across the raw concrete a fine white or grey powder will be on your hand. If you jump on the concrete you will see dust come up off of the surface. The same thing happens to the raw concrete sub-floor deck.