Open the first page—if the copyright date is older than 2018 and there’s no “Reaffirmed 2022” stamp, you need an upgrade.
While 1979 is a commonly cited version, it is important to check for any official errata or revisions as noted by the ASME Performance Test Codes Committee.
This measures the actual volume of gas compressed and delivered by the machine, expressed at specific inlet conditions. PTC 9 outlines the exact types of flow nozzles and orifice plates required to get an accurate reading. Shaft Power