The traditional method to determine the compressed air requirements for a new plant is to add up the air consumption (m3/min) of all pneumatic equipment and then consider adding a safety, leakage, and development factor.
In an existing plant, you can simply perform some basic tests to find out if the compressed air supply is sufficient. If not, you can estimate how much more is needed.
Generally, in industry, the output pressure of an air compressor is 0.69 MPa (G), and the pressure delivered to the equipment usage point should be at least 0.62 MPa. This indicates that the typical air compressors we use have an unloading pressure of 0.69 MPa (G) and a cylinder loading pressure or system pressure of 0.62 MPa (G). With these figures (or the unloading and loading values of a particular system), we can determine accordingly.