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Hitachi Lightning 9900™ User and Reference Guide 113
5.7.3 Loudness
The acoustic emission values [loudness in dB(A)] for a maximum 9960 subsystem
configuration (one DKC, six DKUs) are:
Front/rear = 64 dB(A)
Both sides = 57 dB(A)
Note: These values were extrapolated from the values for one DKC and one DKU.
5.7.4 Air Flow Requirements
The 9900 subsystem is air cooled. Air must enter the subsystem through the air flow intakes
at the sides and bottoms of the frames and must be exhausted out of the tops and sides, so
it is very important that the air intakes and outlets remain clear. Hitachi Data Systems
recommends that under-floor air cooling has a positive pressure and meets the specifications
listed in Table 5.20. For subsystems located at elevations from 3,000 to 7,000 feet (900 to
2,100 meters) above sea level, decrease the maximum air temperature by two degrees for
each 1,000 feet (300 meters) above 3,000 feet (900 meters).
Table 5.20 Internal Air Flow
Subsystem Type Subsystem Configuration Air Flow (ft
3
/min) Air Flow (m
3
/min)
Control Frame with 8 GB Cache Memory, two
8-port Fibre Adapter and additional Disk Adapter
636 18
Control Frame with all options 636 18
9960
Array Frame, fully configured 424 12
9910 Subsystem fully configured 530 15