Site Preparation Guide, Second Edition - HP Integrity cx2620 Server

Table 2-1 Effect of Humidity on ESD Charge Levels
Humidity
2
and Charge Levels (voltages)
3
Personnel Activity
1
50%40%32%26%
3,700 V4,625 V5,750 V6,150 VPerson walking across a linoleum floor
11,100 V13,875 V17,250 V18,450 VPerson walking across a carpeted floor
14,800 V18,500 V23,000 V24,600 VPerson getting up from a plastic chair
1 Source: B.A. Unger, Electrostatic Discharge Failures of Semiconductor Devices (Bell Laboratories, 1981)
2 For the same relative humidity level, a high rate of airflow produces higher static charges than a low airflow rate.
3 Some data in this table has been extrapolated.
For more information regarding ESD, refer to the HP ESD Standard HP-00005-04 at:
http://standards.inet.cpqcorp.net/smc/hpstd/AHP0000504.htm
Relative Humidity
Where possible, maintain a humidity range of 40 percent to 55 percent.
Static Protection Measures
Follow these precautions to minimize possible ESD-induced failures in the computer room:
• Maintain recommended humidity level and airflow rates in the computer room.
• Install conductive flooring (conductive adhesive must be used when laying tiles).
• Use conductive wax if waxed floors are necessary.
• Ensure that all equipment and flooring are properly grounded and are at the same ground
potential.
• Use conductive tables and chairs.
• Use a grounded wrist strap (or other grounding method) when handling circuit boards.
• Store spare electronic modules in antistatic containers.
Acoustics
Computer equipment and air conditioning blowers cause computer rooms to be noisy. Ambient
noise level in a computer room can be reduced as follows:
Dropped ceiling Cover with a commercial grade of fire-resistant, acoustic rated,
fiberglass ceiling tile.
Sound deadening Cover the walls with curtains or other sound deadening material.
Removable partitions Use foam rubber models for most effectiveness.
Facility Characteristics
This section contains information about facility characteristics that must be considered for the
installation or operation of the server. Facility characteristics are:
• Floor loading
• Windows
Floor Loading
The computer room floor must be able to support the total weight of the installed server plus
the weight of the individual cabinets, cabling and peripheral devices.
Floor Loading Terms
Table 2-2 provides floor loading terms and definitions.
36 General Site Preparation Guidelines