HP P10000, Руководство пользователя

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environmental requirements tables, including transients. The system must never be exposed to
conditions that could cause internal condensation to occur within the subsystem.
The air-conditioning units should have controls monitoring under the floor output that respond to
1° C (2° F) and 5 percent relative humidity. Humidification is normally required to replace moisture
removed during the cooling process. The relative humidity for a subsystem equipment room should
be set at 40 percent. This level is sufficient to suppress electromagnetic charge buildup, and low
enough to avoid the risk of corrosion and condensation. To avoid air contamination from the
humidifier, water treatment may be necessary in areas with high mineral content.
Air Supply and Flow
The air flow capacity of the facility where the storage systems are installed needs to be sufficient
to remove the heat generated by the equipment. In addition, the air handlers must provide the
airflow volume required by the units being cooled. To ensure this airflow, the facility must have a
positive under the floor air pressure (if the facility has raised floors). When conditions within the
computer room are changed (new units are added, the computer system is moved) airflow checks
should be made.
The amount of outside (make-up) air should be kept to the minimum needed to create a slight
positive pressure within the room, and should not exceed industry recommendations of 0.3 cubic
meter/minute (10 cubic feet/minute) per person stationed in the equipment room. While
recommendations for outside air in comfort air-conditioning are 10 to 15 percent of the airflow,
the computer room environment is cleaner and operates more efficiently if outside air is kept below
1 percent of the airflow. Cooling/heating and humidification needs are reduced, and a minimum
of contaminated building air is introduced into the installation area.
Air Cleanliness
Air contaminants can cause equipment malfunction and can damage storage systems. It is essential
that steps be taken to prevent air contaminants, such as metal particles, solvent vapors, corrosive
gases, soot, airborne fibers, or salt, from entering or being generated within the server room
environment.
A high-efficiency air filter should be employed on each air inlet for outside air to stop dust at the
point of entry to the installation site. Special additional filtering is necessary where the environment
is exposed to salt air, corrosive gases, or unusual dust/dirt conditions. Electronic equipment is
sensitive to air contaminants such as:
•
Excessive amounts of soot particles
•
Condensate particulates such as carbonates
•
Concrete particulates from unsealed concrete
•
Metal flakes or filings, such as those produced by sawing, filing, or drilling
•
Floor-cleaning solutions with high ammonia content.
•
Deteriorating/decomposing building materials, including floor tiles, fabrics, sheetrock,
insulation, and acoustical tiles
•
Pollutants generated by any servicing performed in and around the computer room
•
Paper chaff, dust, and toners from printers within the computer room
•
Processing chemicals from reproduction equipment such as microfiche processors.
In electronic equipment, contaminants cause connector contact and motor-bearing degradation.
They also cause electrical leakage, shorting paths between integrated circuit leads and between
printed wiring traces on printed circuit boards.
Air supplied to and circulated within the server room and under the floor plenums should ideally
pass through mechanical or electrostatic filters. HVAC ducts and plenums and subfloor areas,
including cable raceway openings where used, should be kept clean. All unused cables, hardware,
Meeting Environmental Conditions 27