Reference Guide

percent of the load, whereas the dry heat of electronic equipment produces a sensible heat ratio
of over 95 percent.
Prior to installation, verify that the operating site is equipped with a cooling system that can support
all thermal emissions. Use the average and maximum thermal emissions of storage system
components listed in Table 14 (page 26) to estimate the cooling requirements for an HP 3PAR
Storage system based on a specific system configuration.
Proper site layout is critical to ensure the ambient temperature near the intake of the system does
not rise beyond the system specifications. Exceeding the maximum ambient temperature for any
period negatively affects the system’s reliability and performance, and continued operation for
extended periods under such conditions might actually cause the system to shut down.
CAUTION: Heated air from nearby equipment should not exhaust into the front of the HP 3PAR
Storage system.
Table 14 Thermal Emissions of Storage System Components
Maximum Thermal EmissionsAverage Thermal EmissionsComponent (Fully Populated)
3,004 BTU/hr
(757 Kcal/hr)
2,164 BTU/hr
(545.3 Kcal/hr)
Controller node (pair)
1
4,973 BTU/hr
(1,253.2 Kcal/hr)
3,657 BTU/hr
(921.6 Kcal/hr)
Drive chassis (single)
9,946 BTU/hr
(2,506.4 Kcal/hr)
7,314 BTU/hr
(1,843.2 Kcal/hr)
Drive chassis (pair)
2
1
Controller nodes can only be installed in pairs.
2
HP 3PAR Storage systems require a minimum of two drive chassis; however, additional drive chassis can be installed
individually.
HP 3PAR Storage systems can tolerate temperature and humidity fluctuations if the specified
guidelines are understood and followed. Exposure to conditions outside the specified ranges may
damage the system or its components.
Before a system is powered on, the air entering the subsystem must be clean and within the ranges
specified for temperatures and humidity. The room humidity must be kept sufficiently low to prevent
condensation on or within the subsystem, and must never exceed the limit specified in the subsystem
environmental requirements tables, including transients. The server 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 HP 3PAR 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 (composition) 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
26 Structural/Environmental Considerations