Airflow - HP 9000 rp3410 Manual

HP equipment will operate in a broad environment within a Controlled Computer room.
Temperature can range from 18–27 °C (64.40–80.60 °F) and humidity can range between 20%–80%
relative humidity (rh).
Use a Best Practice to gain the highest reliability by ensuring the temperature is 20–25 °C (68–77
°F) and humidity range of 40%–50% rh.
IMPORTANT:
for best results. Ensure there are no more than 5 °C (41 °F) change in temperature per hour.
HP temperature and humidity recommendations follow ISA G1
industry standards in the following operating ranges:
• Temperature of 20–25 °C (68–77 °F)
• Humidity of 40%–55% relative humidity
• Filtration at 35%–55% spot efficiency per American Society of Heating, Refrigerating, and
Air-Conditioning Engineers (ASHRAE)
• Air-conditioning heat load limits at 80% of total heating, ventilation, and air-conditioning
(HVAC) capacity

Airflow

A public misperception exists that cool, ambient air is consistent throughout a datacenter. That
is, if the temperature of the room is measured at 20 °C (68 °F), then the equipment should be
stable. In reality, microclimates can exist in various parts of the room such that generated heat
in the equipment might not efficiently make its way out. Microclimates are difficult to detect
and prove; therefore, prevent microclimates by encouraging a high rate of airflow from source
to intake of HVAC and uniform distribution of the heated air. Underflow blockages, such as
cabling and piping, can disrupt the airflow predictability. Improperly positioned floor vent tiles
or equipment can create air dams and decrease airflow.
HP recommends the addition of an Automatic Overtemperature Warning and Shutdown
mechanism to protect all products located in a controlled computer room. At the product level,
there are no industry-wide mechanisms currently available to consistently protect systems such
as mass storage in the event of overtemperature and shutdown. Servers have had this feature.
The same protection is needed to all peripherals located in the controlled computer room to
ensure a more efficient recovery.
Follow these precautions to ensure proper airflow:
• Use a heat load to 80% of total HVAC capacity to maintain a thermal safety margin.
• Place vented floor tiles only in heat load areas.
• Do not place vented floor tiles within two floor tiles of HVAC (thermal short circuit).
• Do not place heat loads closer than two floor tiles of HVAC.
• Be sure the maximum distance from the HVAC to the heat load is less than 75 feet (23 m).
• Seal all cable openings as unsealed openings create a loss of static air pressure.
• Lay out equipment aisles parallel to airflow; not perpendicular to it.
• Concentrate high-density heat loads in a tightly controlled area. High-density loads are
equivalent to one cabinet of 3 kilowatts or more.
• Maintain airspeed through vent tiles between 300 to 600 feet per minute (91.44 to 182.88
meters per minute) for high-density cooling. Air moving too slowly will not supply products
placed higher, while air moving too quickly will bypass products placed lower.
2. HP Controlled Computer Room is equal to the Instrumentation, Systems, and Automation Society (ISA) Class G1,
which states: Mild– Corrosion is NOT a factor in determining equipment reliability.
It is very important to ensure consistency in temperature and humidity variables
2
and ASHRAE established
Environmental Elements 17