Oil analysis frequency

There is no easy answer, oil sampling frequency is determined onsite by considering what resources you have to do the sampling and equipment criticality. You have to take a practical approach and not dive in and sample everything without a plan on how you are going to deal with the results. I would evaluate the criticality of each piece of equipment and start with the most critical items. On my site we have some items that are sampled monthly (large circulating systems, plant air compressors, etc) a few 60 day items. Most equipment is sampled quarterly and our outdoor conveying equipment is sampled every 4 months so we dont have to pull samples when it is -30 degrees outside.

I WAS EMPLOYED WITH SCHEMATIC APPROACH AND HAD TOOK CONTROL AND RAN THE OIL ANALYSIS GROUP.
I SET PARAMETERS FOR THE OIL ANALYSIS GROUP AND MADE RECOMMENDATIONS FOR OUR OIL ANALYSIS PROGRAMS WE HAD SETUP AT VARIOUS PLANTS, ALL TYPES OF EQUIPMENT, ETC...
I FOUND THE FOLLOWING TO BE VERY EFFECTIVE IN ESTABLISHING STRONG TRENDS TO TRACK EQUIPMENT HEALTH USING OIL ANAYSIS AS A PROACTIVE TOOL.
OIL ANALYSIS IN MY OPINION SHOULD BE PERFORMED ONCE A MONTH.
EVERY MONTH AN ISO PARTCICLE COUNT TEST, IF ISO COUNT EXCEEDS THE TARGET LEVEL SET A FERROUS PERCENTAGE COUNT SHOULD BE PERFORMED, OIL VISCOSITY TEST AND LASTLY A MOISTURE CONTENT TEST OR CRACKLE TEST (CHEAPER) IF CRACKLES THEN DO A MOISTURE CONTENT TEST.
JUST REMEMBER A VISUAL OF THE SAMPLE IS THE SIMPLEST. IF YOU CAN SEE THE WEAR PARTICLES WITH YOUR NAKED EYE THEN PARTICLES ARE AT LEAST 40ums IN SIZE OR BIGGER - WHY WASTE TESTS
YOU HAVE PROBLEMS.
EVERY 3 MONTHS A SPECTROGRAPH, TAN / TBN.
ADDITIONAL TESTS SUCH AS FERROGRAPHY ANALYSIS (DMSI IN BC, CANADA) OR DEBRIS ANALYSIS, PATCH TEST, FTIR, ETC... CAN BE DONE DEPENDING ON FINDINGS MADE WITH YOUR MONTHLY BASE TESTS TO AID IN ISOLATING ROOT CAUSES FOR A PROBLEM.
I FOLLOWED ABOVE RELIGIOUSLY AND DID WELL AT MY TRADE.
YOU MUST ALWAYS DO AN EQUIPMENT AUDIT.
THE 1ST MOST IMPORTANT ITEM IN ANY OIL ANALYSIS PROGRAM IS DETERMINING WHETHER OR NOT THE PROPER OIL IS BEING USED, AND OIL VISCOSITY.
YOU CAN DO ALL THE TESTS YOU WANT BUT IF YOU HAVE THE WRONG OIL THEN WHAT'S THE POINT.
PROACTIVE MAINTENANCE SHOULD BE ABLE TO OPTIMIZE UPTIME AND MINIMIZE MACHINE DOWNTIME.
IF YOU PICKUP RESULTS IN THE OIL SHOWING A PROBLEM BUT CANNOT SEE THE PARTICLES BY EYE THEN YOUR EARLY, START PLANNING A STRATEGY OR A METHOD OF ELIMINATING THE ROOT CAUSE BEHIND THE PROBLEM.
I CAN GO ON AND ON ABOUT THIS...
I FOUND HAVING STRATEGICALLY PICKED OIL SAMPLING PORTS TO TAKE LIVE ZONE OIL SAMPLES THROUGHOUT A PIECE OF EQUIPMENT BENEFICIAL IN ISOLATING COMPONENTS ETC...OR EVEN IF A FILTER WAS LOSING ITS' DIRT RETENTION CAPABLITIES.
ONE PICKED SAMPLE PORT WOULD BE THE PRIMARY PORT FOR WHERE SPECTROGRAPH AND TAN TESTS WOULD BE PERFORMED EVERY 3 MONTHS. ALL THE OTHER PORTS WOULD BE SECONDARY SAMPLE PORTS OF WHICH ONLY A PARTICLE COUNT WOULD BE DONE.
USING A BASIC HYDRAULIC SCHEMATIC OR MACHINE LAYOUT AND KNOWING WHERE YOUR SAMPLE PORTS ARE LOCATED AND BASED ON RESULTS OBTAINED YOU CAN EASILY READ INTO THE TOTAL HEALTH OF YOUR SYSTEM. ISOLATE A FAILING COMPONENT AND SO FORTH.
IF YOU LIKE I CAN BE CONTACTED AND I CAN ELABORATE FURTHER.

Monthly samples on all equipment if a fine recomendation from the lab or consultants. However, We who actually work in the plants know that a thousand samples per month or more either aren't going to get done or the follow-up maintenance requests are going to overwhelm the craftsmen. For multimillion dollar machines like turbines or complex hydraulic systems fine, I have no problem with weekly (even daily) visual samples; monthly viscosity, particle count, and ferrous wear; and quarterly spectrographic samples. For the bulk of our conveying equipment and pumps quarterly viscosity, particle counts and ferrous wear analysis has shown to be highly satisfactory.