HP Cluster Platform Site Preparation Guide

D Calculating Noise Levels
Use the following formulas to calculate noise levels:
• Formula 1: The declared A-weighted sound power level according to ISO 9296 and ISO 7779
L
WAd
:
L
WAdT
= log[N
1
*10^(L
WAd1
) + N
2
*10^(L
WAd2
) + …..] in bels.
Where:
— L
WAdT
is the declared A-weighted sound power level for entire rack.
— L
WAd1
is the declared A-weighted sound power level for the first type of server or switch.
— N
1
is the number of the first type of server or switch.
— L
WAd2
is the declared A-weighted sound power level for the second type server or
switch.
— N
2
is the number of the second type of server or switch.
• Formula 2: The declared A-weighted sound power level according to ISO 9296 and ISO 7779
L
pAm
:
L
pAmT
10*log[N
1
*10^(L
pAm1
/10) + N
2
*10^(L
pAm2
) + …..] in decibels.
Where:
— L
pAmT
is the declared A-weighted sound power level for the entire rack.
— L
pAm1
is the declared A-weighted sound power level for the first type of server or switch.
— N
1
is the number of the first type of server or switch.
— L
pAm2
is the declared A-weighted sound power level for the second type of server or
switch.
— N
2
is the number of the second type of server or switch.
For example, a 17-node CBB (with 17 HP Integrity rx2600 servers and one HP ProCurve
model 2650 network switch) has the following noise values according to ISO 9296:
L
pAm
L
WAdT
Mode
59 dBA7.5 BIdle
60 dBA7.6 BOperating
See the specifications documentation for an individual component (such as a server) to obtain
declared noise levels of individual components.
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