Portable Compressors Pressure and Capacity
The standard supply pressure of portable compressors is 7 bar, because practically all construction and hand-held tools are designed to operate at this pressure as a maximum. Most tools will work adequately (but with a reduced performance) at a pressure varying between 4 bar and 7 bar. This flexibility makes compressed air a very versatile medium for use by contractors.
Higher pressures, up to about 20 bar, are also available, intended for such specialist purposes as the supply of air for high performance quarrying drills.
The capacity of portable compressors varies from 1.5 m 3/min up to about 40 m3/min. Note that the traditional designation for the capacity of portable compressors is ft 3/min, and even the products of European suppliers frequently have a reference designation which can be traced to the capacity in these units. (Note that 1 m 3/min = 16.7 l/s = 35.3 ft 3/min).
One frequently comes across the expression one-tool, two-tool up to five-tool compressor. The tool referred to is a concrete breaker or paving breaker with an air requirement of 1.5 m 3/min (25 l/s). Such compressors are capable of running that number of tools simultaneously.