RULER Oil Analysis

Remaining Useful Life Evaluation Routine (RULER®)

Every lubricant application can benefit from RULER testing / RULER Oil Analysis. By proactively measuring the oil’s remaining antioxidants (oxidation fighters) oil degradation can be predicted before risking equipment reliability and increased wear.

RULER determines the remaining useful life of oils and is ASTM listed test method – ASTM D6810 and ASTM D6971.


  • predicts oil oxidation before it occurs
  • customers no longer have to wait for oxidation to measure current levels
  • Customers do not need to risk equipment reliability by running oxidised oils in their system before oxidation is detected

Oxidation of lubricating oil can reduce equipment reliability, equipment protection and can cause

  • Increases in viscosity
  • acid formation (increasing TAN)
  • lubricant degradation
  • formation of varnish
  • waste lubricant that must be replaced

The advantages of RULER over Viscosity,  TAN, FTIR and wear metal analysis

Many conventional testing techniques (kinematic viscosity, total acid number (TAN), infrared (IR) data, and wear metal analysis) are used to measure the extent of oil degradation and only begin to show significant changes in the physical and chemical oil properties when the majority of the antioxidants have been depleted. By this stage the oil has already begun to substantially degrade.

RULER in comparison detects the remaining antioxidants and can be used to predict when oxidation will occur, allowing action to be taken before oil degradation risks equipment reliability and increases wear.

With RULER® test, customers are able to proactively:

  • Monitor the depletion rates of the antioxidant protection package in new and used oils.
  • Quantify antioxidant levels of incoming and stored oil supplies.
  • Identify abnormal operating conditions prior to equipment failure following the detection of abrupt antioxidant depletion rates.
  • Determine proper oil change intervals and extend oil change intervals through timely antioxidant additive replenishment.

Information based oil drains Vs Time based oil drains

To ensure that a lubricant is not used past the end of its useful life, time based oil changes are inherently conservative, which often results in the discarding of lubricants that are still suitable for use. Understanding and forecasting the oxidation process of oils (using RULER) will enable information based oil drains and add value to your Oil Analysis or Condition Monitoring Program.

Contact CTG today to organise RULER® Oil Analysis testing.