Large tonnage field erected compressors find many different and unique applications in varying environments. These include air conditioning, food processing, food storage, industrial and chemical processing, marine service and many more. Each application varies as to its duty cycling, load variation, field maintenance and operational environment and is often beyond the control of the compressor design. Control designers must also consider the design limits of the compressor as well as the total system design.

For many years the elements of quality, mechanical design, cost, design life, manufacturing expertise, and merchantability have been prevalent in the market place. The new force today is reliability. The term reliability adds the dimension of "how long and under what conditions the product will perform".