The Duct System

Air ducts for transmission of air, air heating, ventilation or air conditioning systems should be carefully studied from the point of view of the economy, and for the proper functioning. When designing ducts, the following methods may be used:

Calculate the total amount of air to be handled in a minute, the fan, as well as fractional volumes that make up the total, which will be delivered or withdrawn from different parts of the building.
Locate the power supply in the most convenient place and as close to the center of the distribution.
Dividing the building into zones, and volumes of air per minute, in accordance with the requirements of the various zones.
Locate the air inlets or outlets for the supply and recycling, respectively. The positions located on the building plans, to specify volumes of air to be dealt with. Position inputs and outputs must be such as to produce a thorough air distribution throughout the space provided.
Determine the size of each output or input on passing of necessary quantity of air per minute at the appropriate speed.
To calculate the field, and choose the appropriate size for the whole industry and main ducts. For this based on the creation of equal friction losses on foot in length. This implies a reduction of speed in small ducts.
Determine the resistance of air ducts, which establishes the greatest friction. In most cases, it will be the longest, though not as often. This will be the resistance offered by the overall pipeline system, a tributary of the required air volume.

Revise sizes and areas of shorter works so that the ducts themselves will create coefficient is the longest run. This will reduce the cost of sheet metal, and the result will be exactly the same as if dampers were used. At too high a speed, however, should be avoided.
To compensate for unforeseen circumstances, the amount of absorption should be provided for each branch.