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
Limits for particulates and gases
Contaminant Limits
Particulate
• The room air must be continuously filtered with 40% atmospheric dust spot efficiency (MERV
9) according to ASHRAE Standard 52.2
1
.
• Air that enters a data center must be filtered to 99.97% efficiency or greater, using high-
efficiency particulate air (HEPA) filters that meet MIL-STD-282.
• The deliquescent relative humidity of the particulate contamination must be more than 60%
2
.
• The room must be free of conductive contamination such as zinc whiskers.
Gaseous
• Copper: Class G1 as per ANSI/ISA 71.04-1985
3
• Silver: Corrosion rate of less than 300 Å in 30 days
1
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.
2
The deliquescent relative humidity of particulate contamination is the relative humidity at which the dust absorbs
enough water to become wet and promote ionic conduction.
3
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.
Appendix C. Notices 107
To Next Page