Types of contamination

Types of contamination

Contamination is airborne, and exists in two forms: particulate matter (PM) and gaseous. Both forms in turn break down into different types, which can cause problems in different ways. Also particulate and gaseous contamination can interact, and particulate contamination effects can be modified by ambient humidity levels.

Particulate matter contamination can be solid or liquid. It can originate either from within the data room, elsewhere within the building housing the data centre, or outside the building in the open air environment. If it is generated outside, it can enter the data centre through open doors, through the air handling system, on people’s clothes, on equipment brought into the room, or on packaging for the equipment.

External sources include agricultural dust, sea salt, industrial processes, plant pollens, traffic or possibly fires. Internal sources include toner dust from copiers and printers, paper, human hair, skin and clothing, dirty shoes and cigarette smoke. Building materials, especially concrete which degenerates also contribute. Raised access floors can be a source of zinc whiskers, which are a particularly hazardous form of PM.

Gaseous contamination can be a threat to electronics equipment, mainly through causing corrosion. Gases can occur naturally or as a by-product of industrial or manufacturing processes. Outside pollution such as smog can contain sulphur, bromine and chlorine compounds. The most common gases affecting data centres are Sulphur Dioxide (SO?) and Hydrogen Sulphide (H?S). Some presence of contaminating gases is inevitable, although it can be controlled.