HP rp7405 User Guide, Third Edition - hp rp7405/rp7410 Servers - Page 134

Site Preparation Environmental Elements • Underfloor air distribution system-Downflow air conditioning equipment located on the raised floor of the computer room uses the cavity beneath the raised floor as plenum for the supply air. Perforated floor panels (available from the raised floor manufacturer) should be located around the perimeter of the system cabinets. Supply air emitted though the perforated floor panels is then available near the cooling air intake vents of the computer system cabinets. • Ceiling plenum air distribution system-Supply air is ducted into the ceiling plenum from upflow air conditioning equipment located in the computer room or from an air handling unit (remote). The ceiling construction should resist air leakage. Place perforated ceiling panels (with down discharge air flow characteristics) around the perimeter of the system cabinets. The supply air emitted downward from the perforated ceiling panels is then available near the cooling air intake vents of the computer system cabinets. Return air should be ducted back to the air conditioning equipment though the return air duct above the ceiling. • Above ceiling ducted air distribution system-Supply air is ducted into a ceiling diffuser system from upflow air conditioning equipment located in the computer room or from an air handling unit (remote). Adjust the supply air diffuser system grilles to direct the cooling air downward around the perimeter of the computer system cabinets. The supply air is then available near the cooling air intake vents of the computer system cabinets. Table C-1 Computer Room Environment Parameter Operating Limits Recommended Operating Range Maximum Rate of Change (per hour) Non-Operating Ranges Temperaturea 41° - 95° F (5° - 35° C) 68° - 77° F (20° - 25° C) 20° C/hour -40° C - +70° C Humidity 15% - 80% 40% - 55% RH with no condensation non-condensing (40% - 55% recommended) 30% RH/hour non-condensing 90% RH non-condensing @ 65° C (149° F) a. The temperature ranges stated are at 0 to 5,000 feet. The maximum operating temperature must be de-rated by 1° C/1,000 feet from 5,000 to 10,000 feet. Air Conditioning System Installation All air conditioning equipment, materials, and installation must comply with any applicable construction codes. Installation of the various components of the air conditioning system must also conform to the air conditioning equipment manufacturer's recommendations. Humidity Level Maintain proper humidity levels. High humidity causes galvanic actions to occur between some dissimilar metals. This eventually causes a high resistance between connections, leading to equipment failures. High humidity can also have an adverse affect on some magnetic tapes and paper media. 112 Appendix C