HP Integrity rx8620 Site Preparation Manual page 30

General Site Preparation Guidelines
Environmental Elements
• Air distribution
• System controls adequate to maintain the computer room within specified operating ranges.
Lighting and personnel must also be included. For example, a person dissipates about 450 BTUs per hour
while performing a typical computer room task.
At altitudes above 10,000 feet (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 1,000 foot (305 m) increase in altitude above 10,000 feet (up to a
maximum of 15,000 feet), 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 computer room air-conditioning system 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 server availability, redundant air-conditioning equipment, or capacity.
• The system should be capable of handling any future server 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 condensers. 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.
• Central station air-handling units with remote refrigeration equipment. These systems are usually
located outside the computer room.
Basic Air-Distribution Systems
A basic air-distribution system includes supply air and return air.
An air-distribution system should be zoned to deliver an adequate amount of supply air to the cooling air
intake vents of the server equipment cabinets. Supply air temperature should be maintained within the
following parameters:
• Ceiling supply system—From 55° F (12.8° C) to 60° F (15.6° C)
• Floor supply system—At least 60° F (15.6° C)
If a ceiling plenum return air system or a ducted ceiling return air system is used, the return air grills in the
ceiling should be above the exhaust area or the exhaust row.
The following three types of air distribution systems are listed in order of recommendation:
• Under floor air distribution system—Down flow 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.
24
Chapter 2