Many industries require "engineered" air, air with the right temperature, pressure, and cleanliness including automakers and food and beverage processors. Engineered air is also used for API 672 applications in refining, petrochemical, and oil and gas production." The PAP Plus compressor from FS-Elliot, Jeannette, Pa. (www.fs-elliot.com), is said to be easy to install, operate smoothly, and increase operating efficiencies. It uses backward leaning, stainless-steel impellers to create a steeper pressure rise to surge and give the unit a larger throttle range. The impellers are also less susceptible to surges caused by changing operating conditions, such as air or water temperature, and fouled intercoolers. Redundant pumps provide continuous, reliable oil pressure. And the lube system includes two full-capacity, full-pressure pumps: the shaft-driven main unit and a motor-driven auxiliary. The auxiliary system is used for start-ups, shutdowns, and as an emergency back up. The intercoolers feature a straight-through, water-in-tube design for easy cleaning, inspection, and maintenance. Horizontally split compressors (gear case, bearings, and seals) are also easy to inspect and maintain. The compressor delivers out oil-free, particulate-filtered air at a specified pressure and flow rate.