You must consider the air quality and contamination levels at your installation site.
Airborne particulates (including metal flakes or particles) and reactive gases that act alone or in combination with other environmental factors, such as humidity or temperature, might pose a risk to the storage 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 to malfunction or cease functioning altogether. This specification presents 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.
- Gaseous contamination
- Severity level G1 according to ANSI/ISA 71.04-19851, which states that the reactivity rate of copper coupons must be fewer than 300 Angstroms per month (Å/month, ≈ 0.0039 μg/cm2-hour weight gain)2. In addition, the reactivity rate of silver coupons must be less than 300Å/month (≈ 0.0035 μg/cm2-hour weight gain)3. The reactive monitoring of gaseous corrosivity is 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 selecting one of the following filtration
- 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.
- 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.