Compressed Air Quality and Oil Carryover
The compressed air quality that is needed is
a critical element when it comes to compressor rentals.
Different machines vary widely in terms of the purity of the
Most rental equipment falls into one of three
"air quality" categories:
1. Inherently oil-free compressors,
which do not add ANY oil to the air being compressed;
2, Lubricated compressors with filtration,
most of the oil added to the air during the compression
process is removed via filtration.
3. Standard electric oil-flooded rotary screw
compressors (which usually include aftercoolers) and
Standard Construction grade portable compressors (which
usually do not include aftercooling)..
The benefit of renting inherently oil-free
compressors is obvious – no oil in the air. But because they
are truly oil-free, they rent for higher rates than
For applications that require oil-free
compressed air, it is important to rent only inherently
oil-free compressors, just as it is required to
purchase them for your permanent installations.
The Instrument Society of America definition
of "Instrument Quality" Air is:
A maximum oil content of less than one part
per million (by weight)
The particle size in the air stream must be
less than 40 microns; and
The dew point must be 18ºF below the
minimum temperature to which the air is exposed