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Particulate Contamination - IBM System X High Voltage DC PDU Installation And Maintenance Manual

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Particulate contamination

Attention: Airborne particulates (including metal flakes or particles) and reactive
gases acting alone or in combination with other environmental factors such as
humidity or temperature might pose a risk to the device that is described in this
Risks that are posed by the presence of excessive particulate levels or
concentrations of harmful gases include damage that might cause the device to
malfunction or cease functioning altogether. This specification sets forth limits for
particulates and gases that are intended to avoid such damage. The limits must not
be viewed or used as definitive limits, because numerous other factors, such as
temperature or moisture content of the air, can influence the impact of particulates
or environmental corrosives and gaseous contaminant transfer. In the absence of
specific limits that are set forth in this document, you must implement practices
that maintain particulate and gas levels that are consistent with the protection of
human health and safety. If IBM determines that the levels of particulates or gases
in your environment have caused damage to the device, IBM may condition
provision of repair or replacement of devices or parts on implementation of
appropriate remedial measures to mitigate such environmental contamination.
Implementation of such remedial measures is a customer responsibility.
Table 3. Limits for particulates and gases
v The room air must be continuously filtered with 40% atmospheric dust
spot efficiency (MERV 9) according to ASHRAE Standard 52.2
v Air that enters a data center must be filtered to 99.97% efficiency or
greater, using high-efficiency particulate air (HEPA) filters that meet
v The deliquescent relative humidity of the particulate contamination
must be more than 60%
v The room must be free of conductive contamination such as zinc
v Copper: Class G1 as per ANSI/ISA 71.04-1985
v Silver: Corrosion rate of less than 300 Å in 30 days
ASHRAE 52.2-2008 - Method of Testing General Ventilation Air-Cleaning Devices for
Removal Efficiency by Particle Size. Atlanta: American Society of Heating, Refrigerating
and Air-Conditioning Engineers, Inc.
The deliquescent relative humidity of particulate contamination is the relative
humidity at which the dust absorbs enough water to become wet and promote ionic
ANSI/ISA-71.04-1985. Environmental conditions for process measurement and control
systems: Airborne contaminants. Instrument Society of America, Research Triangle Park,
North Carolina, U.S.A.