ASTM D4378 Standard Practice for In-Service Monitoring of Mineral Turbine Oils
ASTM D4378 Standard Practice for In-Service Monitoring of Mineral Turbine Oils for Steam and Gas Turbines
11. Test Schedules
11.1 Steam and Gas Turbines - Mineral Oils:
11.1.1 The following test schedules are based mainly on tests that can be run by most power station laboratories. An important exception is probably the RPVOT to determine remaining service life where the assistance of an outside laboratory or the oil supplier may be necessary.
11.1.2 New oil should be sampled and tested for agreement with quality requirements as it is received. Upon the installation of a new oil charge, either as an initial fill or as replacement charge, an approximately 4-L (1-gal) sample should be taken after 24-h circulation. This is a most important sample since it is used as the baseline for comparison with later test data. The sample should be retained for at least 12 months. Significant differences in quality between the new oil (as received) and the 24-h sample should be investigated. A check sample is sometimes necessary. Contaminants in the system and residues from degraded oil can adversely affect the potential service life of the new oil charge. The purpose of the initial schedules, 12 months for steam turbines and 4 - 6 months for gas turbines, is to determine the severity of service. For this, fairly frequent sampling and testing is required. The amount of degradation occurring during this initial period serves as a guide to establish future sampling frequency.
11.1.3 The normal test schedules are for systems which normally expect a long service life. The history of the present charge or the results of the first 6 to 12 months testing of a replacement charge is usually sufficient to determine if the normal schedule will apply. Eventually, as test results indicate that the oil is becoming degraded and may be approaching the end of its service life, the sampling frequency should be increased.
12. Keywords
12.1 gas turbines; in-service monitoring; mineral; mineral turbine oil; monitoring program; steam turbines; turbine oil
