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12. CALCULATE AN AIR DISTRIBUTION NETWORK
Pressure drop for 100 m (in bars)
e n g l I s h
Pressure (in bars)
Outside diameter of the tube (mm)
Referential axis
NRA flow rate* (in l/min.)
12.1. Flow rates permitted on the pipes
The quality of the interior surfaces of pipes and fittings guarantees higher flow rates in equivalent sections compared with iron pipes. For all calculations relating to the flow rates disposed of at different levels of pressure by the SICOAIR fittings according to the different diameters available, please refer to the following graph and instructions for their use. The graph can be used in different ways, depending on the starting data and magnitudes to be obtained: a. flow calculation starting from the outside diameter of the pipe, the pressure and the allowable pressure drop. We proceed as follows: first of all there should be a straight line that joins the value of load loss (A axis) with the pressure value (C axis). This straight line intersects the R axis at a point x. Then draw a straight line from x, which intersects axis B corresponding to the outer diameter of the tube. The intersection between the extension of this line and the A axis indicates the flow rate value. b. calculation of the outer diameter of the tube starting from the pressure value, flow rate and the permissible load loss. We proceed as follows: first of all there should be a straight line that joins the pressure value (C-axis) and the value of load loss (A axis). This straight line intersects the R axis at a point x. Then draw a straight line that joins x to the flow rate value required (A-axis); the intersection of this line with the B axis denotes the outer diameter of the pipe to be used. c. calculation of the loss of load, starting from the outer diameter of the pipe, the pressure and flow rate. We proceed as follows: from the flow
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