HP Integrity rx7620 Server - User Service Guide, Sixth Edition

• Use a vapor barrier installed around the entire computer room envelope to restrain moisture
migration.
• Caulk and vapor seal all pipes and cables that penetrate the envelope.
• Use at least a 12-inch raised floor system for the most favorable room air distribution system
(underfloor distribution).
• Ensure a minimum ceiling height of 12 inches between the top of the server and the ceiling
and that all ceiling clips are in place.
• Allow 18 inches (or local code minimum clearance) from the top of the server cabinet to the
fire sprinkler heads.
Cooling Requirements
Air conditioning equipment requirements and recommendations are described in the following
sections.
Basic Air Conditioning Equipment Requirements
The cooling capacity of the installed air conditioning equipment for the computer room should
be sufficient to offset the computer equipment dissipation loads, as well as any space envelope
heat gain. This equipment should include:
• Air filtration
• Cooling or dehumidification
• Humidification
• Reheating
• Air distribution
• System controls adequate to maintain the computer room within the operating range
Lighting and personnel must also be included. For example, a person dissipates about 450 Btu
per hour while performing a typical computer room task.
At altitudes above 10,000 ft (3048 m), the lower air density reduces the cooling capability of air
conditioning systems. If your facility is located above this altitude, the recommended temperature
ranges might need to be modified. For each 1000 ft (305 m) increase in altitude above 10,000 feet
(up to a maximum of 15,000 ft), subtract 1.5° F (0.83° C) from the upper limit of the temperature
range.
Air Conditioning System Guidelines
The following guidelines are recommended when designing an air conditioning system and
selecting the necessary equipment:
• The air conditioning system that serves the computer room should be capable of operating
24 hours a day, 365 days a year. It should also be independent of other systems in the building.
• Consider the long-term value of computer system availability, redundant air conditioning
equipment, or capacity.
• The system should be capable of handling any future computer system expansion.
• Air conditioning equipment air filters should have a minimum rating of 45% (based on
“ASHRAE Standard 52-76, Dust Spot Efficiency Test”).
• Introduce only enough outside air into the system to meet building code requirements (for
human occupancy) and to maintain a positive air pressure in the computer room.
Air Conditioning System Types
The following three air conditioning system types are listed in order of preference:
• Complete self-contained package units with remote condenser. These systems are available
with up or down discharge and are usually located in the computer room.
• Chilled water package unit with remote chilled water plant. These systems are available
with up or down discharge and are usually located in the computer room.
Environmental Elements 187