Overall Lubricant Criticality (OLC)

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Overall Lubricant Criticality, or OLC, is one of the essential foundations of lubrication analysis and inspection. OLC defines the health and longevity of a lubricant based on the probability and consequences of failure. Understanding and establishing OLC helps you develop efficient lubrication and maintenance programs. 

What is Overall Lubricant Criticality?

Overall Lubricant Criticality (OLC) is the total criticality or risk that a lubricant will fail based on the criticality of machine failure, the economic costs of lubricant failure, and the probability of lubricant failure.  

The OLC is calculated using the following equation:


You may be wondering, what are these terms? OMC is Overall Machine Criticality, LCF is Lubricant Criticality Factor, and DOF is Degradation Occurrence Factor.

To learn more about OMC, LCF, and DOF, you can check our in-depth definition of these terms in our Glossary. The following sections will briefly explain each term.

What is Overall Machine Criticality (OMC)?

The Overall Machine Criticality or OMC is the product of machine criticality and probability of failure. Machine criticality, expressed as Machine Criticality Factor (MCF), is a number ranging from 1 to 10 assigned based on the extent of downtime and repair costs. A high MCF means a high risk of prolonged downtime and expensive repairs.

The probability of failure, expressed as Failure Occurrence Factor (FOF), is also assigned values from 1 to 10 based on the recent history of failure and repairs. A high FOF means a high risk of failure due to frequent failures and repairs in the past.

What is Lubricant Criticality Factor (LCF)?

The Lubricant Criticality Factor (LCF) is rated from 1 to 10 based on the costs of lubrication failure. The LCF considers the costs associated with lubrication, which include:

  • Lubricant
  • Loss in profit due to the downtime needed to change the lubricant
  • Expense for the flushing out of the lubricant
  • Materials and personnel used
  • Other costs from system disturbances

The higher the cost of lubrication failure, the higher the LCF rating.

What is Degradation Occurrence Factor (DOF)?

The Degradation Occurrence Factor, or DOF, defines the probability of lubricant failure. The DOF rating of 1 to 10 is based on the identification and evaluation of all possible sources of lubricant degradation.

The factors that affect the degradation of lubricants include: 

  • Lubricant quality and suitability
  • Temperature and pressure conditions
  • Exposure or presence of contamination
  • Lubricant volume
  • Lubricant replenishment

The higher the risk of lubricant degradation, the higher the DOF rating.

Overall Lubricant Criticality and Maintenance Programs

What is the role of Overall Lubricant Criticality in maintenance programs? Below are the benefits of computing OLC:

Priority Identification

By ranking the lubricant criticality, you’ll know which assets to prioritize. This way, you don’t waste time and valuable resources on low-priority assets. Instead, you can focus on assets that need your attention the most. 

Resources Allocation

By knowing which assets to prioritize, you have a needs-based way of allocating materials and resources. You can also plan your budget better and purchase essential inventories based on critical maintenance or lubrication needs.

Cost-Effective Lubrication

By knowing which lubrication needs are the most critical, you can save up on non-essential lubrication costs. For example, you can limit your purchase of lubricants for a low-OLC machine. You can also adjust the frequency of performing oil analysis and focus only on high OLC machines, saving on testing costs.

Streamlined Inspection Routes

By knowing which lubrication and inspection areas to prioritize, you can set streamlined and efficient inspection routes. You can lessen the inspection frequency for low-OLC assets and devote more time and care for high-OLC ones. Streamlining inspection routes increases the technician’s focus and facilitates more accurate and timely detection of issues and failures.

OLC Support in Redlist Lubrication Management Software

A Lubrication Management Software like Redlist can help you determine the OLC of your assets. With Redlist’s digitized lube and inspection charting and real-time data, you will have accurate and relevant OLC ratings in no time.

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