Air Conditioning Ducts; Cabling Requirements - HP BL685c - ProLiant - 4 GB RAM Site Planning Manual

Air conditioning ducts

Use separate computer room air conditioning duct work. If it is not separate from the rest of the building,
it might be difficult to control cooling and air pressure levels. Duct work seals are important for
maintaining a balanced air conditioning system and high static air pressure. Adequate cooling capacity
means little if the direction and rate of air flow cannot be controlled because of poor duct sealing. Also,
the ducts should not be exposed to warm air, otherwise humidity levels can increase.

Cabling requirements

HP recommends using overhead cabling systems in high-density environments. Placing the cables in
overhead raceways maximizes airflow and makes access for servicing and upgrades more efficient.
The cable lengths are determined by the cabling specifications for the type of interconnect to which they
are attached. When planning the cable installation, ensure the following:
•
Cable lengths are less than the maximum allowable cable length for the cable and interconnect type.
•
Cable bend radii are greater than the minimum for the cable type used.
To determine the routing restrictions, do the following:
Determine the cable length limits for a specific model of interconnect.
1.
Estimate the cabling constraints for interrack connections, referring to the example presented in the
2.
following figure where:
A = rack height (such as 2 m for a 42U rack)
o
B = distance from the bottom of the rack to the underfloor trough or raceway
o
C = distance to the overhead cable raceway
o
D = distance between the racks
o
In the following figure, examples of the maximum cable run distances are shown by the dotted lines
labeled Overhead and Underfloor.
General site preparation guidelines 11