HP 9000 rp8420 Server - User Service Guide, Fifth Edition

cables. The Federal Communications Commission (FCC) regulates a portion of this problem
through Part 15 of their rules and regulations. Even more stringent than the FCC Part 15
requirements, Network Equipment Building Standards (NEBS) covers a large range of
requirements including criteria for personnel safety, protection of property, and operational
continuity. The documents cover both physical requirements including: space planning,
temperature, humidity, fire, earthquake, vibration, transportation, acoustical, air quality and
illumination; and electrical criteria including: electrostatic discharge (ESD), electromagnetic
interference (EMI), lightning and AC power fault, steady state power induction, corrosion, DC
potential difference, electrical safety and bonding and grounding.
O-R
PCA Printed Circuit Assembly; also referred to as a printed circuit board (PCB).
PCI Currently, the most popular local I/O bus, the Peripheral Component Interconnect (PCI) bus
was developed by Intel and introduced in 1993.
PICMG A consortium of companies involved in utilizing PCI for embedded applications. The PCI
Industrial Computer Manufacturers Group (PICMG) controls the PICMG specification.
Power factor The ratio of true power to apparent power in an AC circuit. In power conversion technology,
power factor is used in conjunction with describing the AC input current to the power supply.
RMS Root-mean-square. Term that refers to the most common mathematical method of defining the
effective voltage or current of an AC wave. To determine RMS value, three mathematical
operations are carried out on the function representing the AC waveform: (1) The square of the
waveform function (usually a sine wave) is determined. (2) The function resulting from step 1
is averaged over time. (3) The square root of the function resulting from step 2 is found.
S-T
Theoretical
maximum power
consumption
Maximum wattage of a given configuration, assuming worst-case conditions (thermal tolerances,
workloads, and so forth) on all system components. It is extremely unlikely that any customer
will experience this level of power consumption.
Tonnage The unit of measure used in air-conditioning to describe the heating or cooling capacity of a
system. One ton of heat represents the amount of heat needed to melt one ton (2000 lb) of ice
in one hour and 12,000 Btu/h equals one ton of heat.
True power In an AC circuit, true power is the actual power consumed. It is distinguished from apparent
power by eliminating the reactive power component that may be present.
Typical input
current
The operating current of the product measured using a typical load and target voltage.
Typical power
consumption
Represents the expected power consumption of a given configuration. The typical value is the
approximate power consumption that a customer will most likely experience and can use for
power budgeting purposes.
U-Z
Vapor seal A vapor seal is an essential part of preventing moisture infiltration into or migration out of a
critical space, such as a data processing center or other room that contains sensitive electronic
instrumentation. Essentially, a vapor seal is a barrier that prevents air, moisture, and
contaminants from migrating through tiny cracks or pores in the walls, floor, and ceiling into
the critical space. Vapor barriers can be created using plastic film, vapor-retardant paint, vinyl
wall coverings, and vinyl floor systems, in combination with careful sealing of all openings
(doors and windows) into the room.
Watt A unit of electricity consumption representing the product of amperage and voltage. When the
power requirement of a product is listed in watts, you can convert to amps by dividing the
wattage by the voltage. (for example, 1200 W divided by 120 V equals 10 amps).
212 Site Preparation Glossary