HP Integrity rx4640 Site Preparation Guide, Second Edition - HP Integrity rx46 - Page 16

System Specifications Environmental Specifications Environmental Specifications This section provides the temperature/humidity requirements, noise emission, and air flow specifications for the HP Server. Temperature and Humidity Ambient intake air temperature is often different from ambient room temperature; you should measure the operating temperature and humidity directly in front of the cabinet cooling air intakes rather than just checking ambient room conditions. Operating Environment The system is designed to run continuously and meet reliability goals in an ambient temperature of 5° C-35° C at sea level. The maximum allowable temperature is derated 1° C per 1,000 feet of elevation above 5,000 feet above sea level up to 30° C at 10,000 feet. For optimum reliability and performance, the recommended operating range is 20° C to 25° C and 40%-50% relative humidity. Environmental Temperature Sensor To ensure that the system is operating within the published limits, the ambient operation temperature is measured using a sensor placed on the system I/O board. Data from the sensor is used to control the fan speed and also to initiate system overtemp shutdown. Nonoperating Environment The system is designed to withstand ambient temperatures between -40° C to 70° C under nonoperating conditions. Cooling CPU/Memory Cooling The cabinet incorporates front to back airflow across the CPU/memory boards and through the HDD backplane. Four 127 mm fans, mounted vertically in the center of the chassis, pull air through the CPU and memory section, and push air through the PCI section. Each CPU/memory dedicated fan is controlled by smart fan control circuitry embedded in the system I/O board. The smart fan control circuitry receives fan control input from the system fan controller in the I/O board, and returns fan status information to the system fan controller. The smart fan circuitry controls the power and the pulse-width-modulated control signal to the fan and monitors the speed indicator back from each of the fans. The fan status LED is driven by the smart fan circuitry. The location of the fan status LED is on the diagnostic board inside the system. Bulk Power Supply Cooling Cooling for the bulk power supplies is provided by the two 120 mm system fans and one externally mounted 60 mm power supply fan. Air is pushed through the power supply by the 120 mm fans and exhausted out the rear by the 60 mm fan (one fan per PSU). Air is ducted out of the rear of the chassis with minimal leakage into the cell airflow plenum. 16 Chapter 1