HP rp8400 Series Manual page 38

Electrical and Environmental Guidelines
Environmental Elements
• Humidification
• Reheating
• Air distribution
• System controls adequate to maintain the computer room within the operating ranges listed in Table 1-7
on page 9.
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 may need to be
modified. For each 1000 feet (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 listed in Table 1-7 on page 9.
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 unit(s) with remote condenser(s). 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 computer system 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)
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Chapter 2