Site Preparation Guide, Eighth Edition - Superdome HP 9000 Systems

Chapter 2
Electrical and Environmental Guidelines
Environmental Elements
45
• System controls adequate to maintain the computer room within the operating ranges listed in Table 2-1.
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 1-14 on page 31.
Air Conditioning System Guidelines
The following guidelines are recommended when designing an air conditioning system and selecting the
necessary equipment:
• The air conditioning system serveing 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 “AShRA 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 u, 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.
Table 2-1 Computer Room Environment
Parameter Operating Range
Recommended
Range
Maximum Rate of Change (per
hour)
Temperature
a
,
b
a. At altitudes up to 3,000 (9,842) meters.
b. System also requires 2400 CFM airflow.
68° to 86° F
(20° to 30° C)
68 to 72 °F
(20° to 23° C)
9° F repetitive,
36° F nonrepetitive
(5° C repetitive,
20° C nonrepetitive)
Humidity 15% - 80%
with no condensation
(40% - 55% recommended)
6%