Oil Analysis Blog-

Oil Analysis Blog

Know the Proper Base Number of Your Oil


“What base number should oil have?”

The base number (BN) is a property that is more associated with engine oils rather than industrial oils. It can be defined as the oil’s ability to neutralize acids that are produced during use. The higher the base number in the engine oil, the more acid it will be able to neutralize during use.

New engine oils usually have a range of 5 to 15 BN. As oil is used in service, it becomes contaminated with acids, causing the base number to drop over time. By using oil analysis for your engine oil, you will be able to track the BN of your oil and determine how much life is remaining. Once the base number drops below 3, this is considered too low and should trigger an oil change for your engine.

The most common reasons for a drop in the base number are related to low-quality fuel and oil oxidation. During combustion, a low-quality fuel with high sulfur content can produce sulfuric acid, which attacks the oil and causes a drop in the base number. Oil oxidation as a result of the engine overheating or an attempt to extend the oil drain interval is another reason you may see a drop in the BN.

The acid number (AN) is a property that is generally more associated with industrial oils than engine oils. It is the amount of acid and acid-like substances in the oil. As mentioned previously, oil oxidation is one of the main producers of acid.

As oil is used in service, acidic components are generated and build up in the lubricant, with the end result being an increase in the acid number. A high acid number represents the potential for corrosion, rust and oxidation. It can also be a signal to perform an oil change. Again, by using oil analysis, you will be able to track the AN of your oil and schedule oil changes.

You also will need to set a critical limit for when the acid number reaches a certain number in order to schedule an oil change. This critical limit will be dependent on the type of oil being used. Typically, for R&O or light-duty oils, a maximum acid number limit of 2 is appropriate. For anti-wear and extreme pressure (EP) oils, an AN limit of 4 is a good starting point.

This article was taken from Machinery Lubrication.

Oil Analysis and its Role In Equipment Reliability


Selecting the proper lubricant, along with careful maintenance of that lubricant, is essential to ensure adequate protection to any machine. Proper lubrication is defined as a correct amount of the correct lubricant at the correct time.

Maintaining a lubricant means ensuring that it has the correct viscosity and the necessary additives for the application. Steps must be taken to keep the lubricant clean and serviceable. Oil analysis is the most effective way to prolong the useful life of lubricants, while maintaining maximum protection of equipment.

Oil analysis tests reveal information that can be broken down into three categories:

  1. Lubricant condition: the assessment of the lubricant condition reveals whether the system fluid is healthy and fit for further service, or is ready for a change.
  2. Contaminants: increased contaminants from the surrounding environment in the form of dirt, water and process contamination are the leading cause of machine degradation and failure. Increased contamination indicates that it is time to take action in order to save the oil and avoid unnecessary machine wear.
  3. Machine wear: an unhealthy machine generates wear particles at an exponential rate. The detection and analysis of these particles assist in making critical maintenance decisions. Machine failure due to worn out components can be avoided. It is important to remember that healthy and clean oil leads to the minimization of machine wear.

Lubricant condition is monitored with tests that quantify the physical properties of the oil to ensure that it is serviceable. Metals and debris associated with machine wear are measured to monitor equipment health. Some tests target specific contaminants that are commonly found in oils.  It is imperative to select the proper blend of tests to monitor the machine’s lubricant condition, wear debris and contaminants in order to meet the goals of successful oil analysis.

The Basics of Lubrication


Lube oil analysis is used extensively to help companies maintain their equipment. In order to take full advantage of the test data from oil samples, it is important to understand the basic properties of a lubricant.  Equally important is the understanding of how these properties affect the ability of the lubricant to function. Lastly, knowledge of the common test techniques and instrumentation used to analyze oil can aid in data interpretation and lead to more productive corrective action.

To effectively monitor how well a lubricant is working, the functions of the lubricant must be understood. The primary function of a lubricant is quite obviously to lubricate (that is, to reduce friction). By reducing friction, wear is reduced, as is the amount of energy required to perform the work.

When the proper lubricant is used, and the proper load is applied, the asperities are not in contact and in theory no wear will occur. When inadequate lubrication is present, or the load is increased, the oil film will not be thick enough to fully separate the asperities. Mixed lubrication, a cross between boundary and hydrodynamic lubrication, occurs when the oil film thickness is equal to the average asperity height. The largest asperities will come in contact, resulting in increased wear.

Many oils are fortified with anti‐wear additives to combat wear under these circumstances. As load continues to increase, or lubrication degrades, boundary lubrication occurs and the oil film thickness cannot separate the friction surfaces. This can result in metal‐to‐metal contact. At this point, asperities are adhering to one another, causing severe machine wear. This can also manifest itself during periods of shock loading, startup or shutdown. Extreme pressure additives are used in oils that frequently encounter these types of situations.

Lubricants also control the temperature of the equipment. Oil absorbs heat generated at the friction surface and carries it away to be dispersed. Many systems incorporate heat exchangers or radiators to aid in removing heat from the system. Along with heat, lubricants transport dirt and other debris away from the friction surface.

Particulate contamination leads to increased wear through abrasion and reduced oil flow. Some oil additive packages contain agents that break up contaminants and hold them in suspension to be filtered out. This prevents harmful deposits and varnish from forming within the equipment. Alkaline additives also protect the components by neutralizing acid and preventing corrosion.

Hydraulic oils have the added function of transmitting power. To function properly, hydraulic oil must be clean and free of contaminants. Many contaminants will cause oil to foam and entrain air or water. Entrained air causes the oil to compress under pressure, resulting in a loss of power. Particulate contaminants can cause the control valves to malfunction and restrict the oil flow.

To learn more about lubrication, check our TestOil’s webinar calendar for dates offering “The Basics of Lubrication.”

Best Practices For Proper Lubrication Storage and Handling


Having lubrication storage and handling systems in place is extremely important. Lubrication products are expensive, so they need to be handled in a fashion that maximizes your return on investment.

Make sure your storage and handling areas are clean, well organized, and climate controlled. You are responsible for ensuring the new oil and grease placed in your equipment is clean and dry, and has not been exposed to extreme temperature variations.

If you have oil storage racks, consider separate pumps and filters for each different lubricant. Furthermore, make sure your transfer containers are clean and be sure not to expose lubricants to contamination in route to the equipment.

Test all your oil for acceptance before placing it into your system for use. Doing so is especially valuable with bulk shipments, because you never know what was in the tanker before your load of oil.

Reasons for using proper lubrication handling and storage:

  • Protect lube products from environment
  • Protect from plant dirt/moisture/sunlight
  • Filter new lubes or lubes as you use them
  • Keep lubes separate from other plant chemical/products