HP 9000 Superdome SX2000 Generic Site Preparation Guide - Edition 6 - Page 18

Also be aware that the racking cabinets are integral to the proper environmental support for mounted equipment. See the following additional items: • Cabinet blanking panels must be used in non-populated U-space levels to prevent unpredictable air mixing. This can lead to No Trouble Found (NTF) diagnosis. • Use the highest percentage cabinet perforation possible to allow the proper ventilation in the cabinet. • Cabinet doors must be used in the front and the rear. They must be grounded to the cabinet using existing ground lugs and ground straps or cables. Equipment Orientation Data center equipment orientation, or heat load, must encourage sufficient airflow. If exhausted heat must move over or around a cabinet, air vortexes might be created, resulting in airflow inefficiency throughout the data center and inside the equipment. Equipment might develop internal hot spots, resulting in sluggish performance or even system failure. Rather than designing a layout to maximize a planning grid worksheet whitespace, create "hot" and "cold" aisles. In a hot aisle, equipment is oriented so that exhaust vents face other exhaust vents. In a cold aisle, intake vents face other intake vents. Place vent tiles in the cold aisles, with few to no vent tiles in the hot aisle. Position equipment in parallel to encourage the lowest air resistance and turbulence. Consider the following when determining equipment orientation: • Orient equipment in parallel to airflow. • Place cabling in such a way as to aid airflow rather than impede it. • Arrange equipment to form hot and cold aisles. • Use vent tiles to control airflow in heat load areas. • Place vent tiles in cold aisles. • Place higher heat load devices at floor level. 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 product installation: 18 General Site Preparation Guidelines