We have a centrifugal compressor driven by a motor. It has lube oil system consisting of pumps, coolers, filters, overhead tank, rundown tank etc. During the last Shutdown we analyzed the oil in the oil reservoir for moisture content and found to be 0.4 % w/w.
Our concern is...
1. How much moisture, in percentage or ppm, is acceptable in lube oil?
2. Is there any standard/code or reference available in this regard?