Required Air Quality Levels; Contaminant Properties And Sources - Oracle StorageTek SL3000 System Assurance Manual

Required Air Quality Levels

Required Air Quality Levels
Particles, gasses and other contaminants may impact the sustained operations of
computer hardware. Effects can range from intermittent interference to actual
component failures. The computer room must be designed to achieve a high level of
cleanliness. Airborne dusts, gasses and vapors must be maintained within defined
limits to help minimize their potential impact on the hardware.
Airborne particulate levels must be maintained within the limits of ISO 14644-1 Class 8
Environment. This standard defines air quality classes for clean zones based on
airborne particulate concentrations. This standard has an order of magnitude less
particles than standard air in an office environment. Particles ten microns or smaller
are harmful to most data processing hardware because they tend to exist in large
numbers, and can easily circumvent many sensitive components' internal air filtration
systems. When computer hardware is exposed to these submicron particles in great
numbers they endanger system reliability by posing a threat to moving parts, sensitive
contacts and component corrosion.
Excessive concentrations of certain gasses can also accelerate corrosion and cause
failure in electronic components. Gaseous contaminants are a particular concern in a
computer room both because of the sensitivity of the hardware, and because a proper
computer room environment is almost entirely recirculating. Any contaminant threat
in the room is compounded by the cyclical nature of the airflow patterns. Levels of
exposure that might not be concerning in a well ventilated site repeatedly attack the
hardware in a room with recirculating air. The isolation that prevents exposure of the
computer room environment to outside influences can also multiply any detrimental
influences left unaddressed in the room.
Gasses that are particularly dangerous to electronic components include chlorine
compounds, ammonia and its derivatives, oxides of sulfur and petrol hydrocarbons. In
the absence of appropriate hardware exposure limits, health exposure limits must be
used.
While the following sections will describe some best practices for maintaining an ISO
14644-1 Class 8 Environment in detail, there are some basic precautions that must be
adhered to:
Do not allow food or drink into the area.
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Cardboard, wood, or packing materials must not be stored in the data center clean
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area.
Identify a separate area for unpacking new equipment from crates and boxes.
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Do not allow construction or drilling in the data center without first isolating
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sensitive equipment and any air targeted specifically for the equipment.
Construction generates a high level of particulates that exceed ISO 14644-1 Class 8
criteria in a localized area. Dry wall and gypsum are especially damaging to
storage equipment.

Contaminant Properties and Sources

Contaminants in the room can take many forms, and can come from numerous
sources. Any mechanical process in the room can produce dangerous contaminants or
agitate settled contaminants. A particle must meet two basic criteria to be considered a
contaminant:
It must have the physical properties that could potentially cause damage to the
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hardware.
B-2 StorageTek SL3000 Systems Assurance Guide