Air distribution center speaks to building conditioned air and building air supply provides the means by which conditioned air, either heated or cooled, is transferred from the point where it is conditioned to the space to be conditioned or the occupied spaces of the building.
Dependent on the building mechanical systems design, the air distribution systems may be located in main mechanical systems located in penthouse or basement mechanical rooms dedicate for this purpose.
Air systems may also be located in mechanical rooms which are located on each floor or above the ceiling tile in the more remote areas of the building or facility.
The system is comprised of fans, coils, filters, dampers, ducts and a transfer medium, air. The ducts provide a path in which the air can be delivered to the conditioned space. The air can provide either cooling or heating.
Basically duct systems are either high, medium or low pressure, high or low velocity and either single or dual duct and either constant air volume or variable air volume.
A single or dual duct constant volume air system provides a constant flow of air at varying temperatures.
A single or dual duct variable volume air system provides a varying flow of air at a constant temperature.
High Pressure Ductwork
High pressure means the air in the ducts is exerting a pressure between 6" and 10" water gauge and requires a Class 111 fan. The seams of the duct are usually welded to eliminate leakage normally to less than 1 percent.
Medium Pressure Ductwork
Medium pressure means the air in the ducts is exerting a pressure of between 2" and 6" water gauge and is used with a Class 11 fan.
Low Pressure Ductwork
Low pressure means the air in the duct is exerting a pressure of less than 2" water gauge and is normally used with a Class 1 fan. It is also used on systems where the velocity of the air is 2000 fpm or less.
High Velocity Ductwork.
High velocity means the speed of air moving through the ducts is more than 2000 fpm.
Low Velocity Ductwork.
Low velocity means the speed of the air moving through the ducts is 2000 fpm or less.