Contamination information that pertains to the system is included in this
topic.
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 system hardware. Risks that are posed by the presence of excessive particulate levels or
concentrations of harmful gases include damage that might cause the
system
hardware to malfunction or cease functioning altogether. This specification specifies 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 specified in this document, you must implement
practices that maintain particulate or 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
caused damage to the system hardware, IBM might require remedial measures to mitigate such environmental
contamination. Implementation of appropriate remedial measures might be necessary before IBM
provides repair or replacement of the
system
hardware. Implementation of such remedial measures is a customer responsibility.
The following criteria must be met:
- Gaseous contamination
- Severity level G1 as per ANSI/ISA 71.04-19851, which states that the reactivity rate
of copper coupons shall be less than 300 Angstroms per month (Å/month, ≈ 0.0039
μg/cm2-hour weight gain)2. In addition, the reactivity rate of silver coupons shall be
less than 300Å/month (≈ 0.0035 μg/cm2-hour weight gain)3. The reactive
monitoring of gaseous corrosivity should be conducted approximately 2 inches (5 cm) in front of the
rack on the air inlet side at one-quarter and three-quarter frame height off the floor, or where the
air velocity is much higher.
- Particulate contamination
- Data centers must meet the cleanliness level of ISO 14644-1 class 8. For data centers without
airside economizers, the ISO 14644-1 class 8 cleanliness can be met by choosing one of the following
filtration methods:
- The room air can be continuously filtered with MERV 8 filters.
- Air entering a data center can be filtered with MERV 11, or preferably MERV 13 filters.
For data centers with airside economizers, the choice of filters to achieve ISO class 8
cleanliness depends on the specific conditions present at that data center. The deliquescent
relative humidity of the particulate contamination should be more than 60% RH4. Data
centers must be free of zinc whiskers5.
- ANSI/ISA-71.04.1985. Environmental conditions for process measurement and control systems:
Airborne contaminants. Instrument Society of America, Research Triangle Park, NC, 1985.
- The derivation of the equivalence between the rate of copper corrosion product thickness growth
in Å/month and the rate of weight gain assumes that Cu2S and Cu2O grow
in equal proportions.
- The derivation of the equivalence between the rate of silver corrosion product thickness growth
in Å/month and the rate of weight gain assumes that Ag2S is the only corrosion
product.
- The deliquescent relative humidity of particulate contamination is the relative humidity at
which the dust absorbs enough water to become wet and promote corrosion, ion migration, or
both.
- Surface debris is randomly collected from 10 areas of the data center on a 1.5 cm diameter disk
of sticky, electrically conductive tape on a metal stub. If examination of the sticky tape in a
scanning electron microscope reveals no zinc whiskers, the data center is considered free of zinc
whiskers.