Table 28. Limits for particulates and gases
Contaminant Limits
Particulate
• The room air must be continuously ltered with 40% atmospheric dust spot efciency
(MERV 9) according to ASHRAE Standard 52.2
1
.
• Air that enters a data center must be ltered to 99.97% efciency or greater, using
high-efciency particulate air (HEPA) lters 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 Efciency 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.
Restriction of Hazardous Substances Directive (RoHS)
This topic provides statements about the Restriction of Hazardous Substances Directive (RoHS).
90 ThinkServer User Guide
