Compressed Air Best Practices, July 2014, by Jan Hoetzel.
http://www.airbestpractices.com/system-assessments/compressor-controls/compressed-air-system-simulation-software

"Over the years and many compressed air audits later, one thing has become clear: continuous monitoring is a key factor for efficient compressed air systems. Similarly, the only constant in a compressed air system is change. When new air applications are added, a line is down, air leaks grow or if maintenance is done to repair leaks in the system, the whole system is affected and responds accordingly. Due to the nature of compressed air systems, improvements may be quickly lost shortly after implementation and go unnoticed. System monitoring allows operators and facilities maintenance to see real time effects of changes to the system and respond with appropriate adjustments when necessary."