Sea Technology

AUG 2017

The industry's recognized authority for design, engineering and application of equipment and services in the global ocean community

Issue link:

Contents of this Issue


Page 42 of 76

42 st / August 2017 ing and Materials (ASTM), British Standards Institute (BSI), Deutsches Institut für Normung (DIN) and the Society of Tribologists and Lubrica- tion Engineers (STLE), has upheld the ISO Viscosity Grade (ISO VG) as the definitive measurement stan- dard for both lubricant suppliers and OEMs. A standard test used to measure viscosity is ASTM D445, which measures kinematic viscos- ity at 40° and/or 100° C. Total Acid Number. Hydrolytic stability is the ability of a lubricant to resist chemical decomposition in the presence of water and is quan- tified by measuring acidity levels within the fluid. ASTM D664 is the standard test method to determine the Total Acid Number (TAN) value in a given sample of hydraulic fluid. This metric is used as a guide to de- termine the extent to which lubri- cation degrades over time, and it indicates the development of acidic elements in fluid as a result of oxi- dation under stress. Acid development in fluid sam- ples, trended over time, provides information regarding the pro- jected longevity of hydraulic fluid. Over time and under stress, the TAN value of fluid rises, indicating a product at the end of its lifespan and in need of replacement, re- quiring premature oil change outs and equipment downtime. Addi- tionally, acidic elements can lead to accelerated rust, corrosion, wear and seal degradation, further damaging the equipment itself. Damage incurred to the hydrau- lic system will lead to equipment failure at best, and could result in severe safety incidents for operat- ing personnel. The current industry standard for condemning oil limit is a TAN measurement of 2.0 units for petroleum products (ASTM D664). RSC Bio Solutions indicated in a 2014 report that environmentally acceptable lubricants (EALs) can oper- ate at above an absolute TAN measurement of 2.0 with no negative impact on the performance of the fluids. There- fore, with EALs, the condemning limit is a TAN greater than 4.0, and when the oil exceeds 2.0 TAN a cautionary note is documented. Let's look at the results from a sample industry in-ser- vice oil analysis. These results indicate that HEES (hydrau- lic environmental synthetic esters) exceeds the established cautionary limit of 2.0 at approximately 26,000 hours of service, while RSC EnviroLogic HF 46 HP maintains a fairly consistent level well below the standard TAN limits. to ensure lubricant and machinery optimization. Oil Viscosity. To measure fluid's resistance to flow, or shear stress, the International Organization for Standardiza- tion (ISO), in agreement with the American Society for Test- (Top) Plot of the results from a sample industry in-service oil analysis, showing condition monitoring according to ASTM D664. In comparison are the performance of HEES and RSC EnviroLogic HF 46 HP (formerly EnviroLogic 3046). (Bottom) Sample data from an offshore drilling platform showing wear metal concentration. The level of iron and copper never ap- proached the caution threshold during all measured hours of operation using RSC EnviroLogic HF 46 HP (formerly Envi- roLogic 3046).

Articles in this issue

Links on this page

Archives of this issue

view archives of Sea Technology - AUG 2017