Electrostatic Discharge (Esd): Source Of Greatest Failure Rate Without Detection; Cellular Telephone And Wireless Usage; Comprehensive Discussion; Computer Room Preparation - HP Rp3440-4 - 9000 - 0 MB RAM Manual

Electrostatic Discharge (ESD): Source of Greatest Failure Rate Without Detection

Computer equipment is increasing in processor and memory density even as size continues to
decrease. These smaller, more densely packed pieces of equipment are at greater risk to damage
from electrostatic discharge. ESD created by the human body can be any voltage from zero, some
voltages beginning at twenty five volts (25V). ESD that is felt by the human body can be 3,000
volts.
Contemporary electronic technology can be damaged or upset by voltages far lower than the
human experience would indicate.
HP recommends building this consideration into your designs for floor coverings, humidity
control, airflow, dust control, and personnel traffic. Consider the following precautions to prevent
or minimize ESD:
• Use antistatic flooring.
• Maintain humidity at 40%–55% relative humidity.
• Follow airflow recommendations.
• If raised flooring is present, use a 2-foot by 2-foot (61-cm by 61-cm) grounding grid.
• Always use appropriately sized AC power ground wires.
• Limit personnel traffic to two floor tiles away from equipment.

Cellular Telephone and Wireless Usage

HP recommends not using cell phones within a data center, especially within 9.8 feet (3 m) of
any high-availability equipment.

Comprehensive Discussion

The following environmental elements can affect a server installation:
•

Computer room preparation

• Airflow
• Cooling requirements
• Humidity level
• ESD prevention
• Acoustics
Computer Room Preparation
Consider the following guidelines to prepare a computer room for a server:
• Locate the computer room away from the exterior walls of the building to avoid the heat
gain from windows and exterior wall surfaces.
• When exterior windows are unavoidable, use windows that are double- or triple-glazed
and shaded to prevent direct sunlight from entering the computer room.
• Maintain the computer room at a positive pressure relative to surrounding spaces.
• Use a vapor barrier installed around the entire computer room envelope to restrain moisture
migration.
• Caulk and vapor seal all pipes and cables that penetrate the envelope.
• Use a raised floor system at least 18 inches (45.72 cm) high for the minimum favorable room
air distribution to ensure good static air pressure beneath the flooring (under floor
distribution).
• Ensure a minimum clearance of 12 inches (30.48 cm) between the top of the server cabinet
and the ceiling to allow for return airflow and to ensure that all ceiling tiles are in place,
except where fire sprinkler heads call for greater clearance.
• Allow 18 inches (45.72 cm) (or local code minimum clearance) from the top of the server
cabinet to the fire sprinkler heads.
Environmental Elements 17