Total Base Number

Total Base Number

Total Base Number (TBN) is a measure of a lubricant's reserve alkalinity. It is measured in milligrams of potassium hydroxide per gram (mg KOH/g).

TBN determines how effective the control of acids formed will be during the combustion process. The higher the TBN, the more effective it is in suspending wear-causing contaminants and reducing the corrosive effects of acids over an extended period of time.

The associated measurement ASTM D2896 and ASTM D4739-06 generally range from 6-80mg KOH/g in modern lubricants, 7-10mg for general automotive use and 10-15 for Diesel operations.

Marine grade lubricants generally will run from 15-50mgKOH/g, but can be as high as 70 or 80mg KOH/g as is the case of Exxon’s MobileGuard 570 or respectively Castrol’s Cyltech 80AW this high level is designed to allow a longer operating period between changes, under harsh operating conditions. When the TBN is measured at 2mg KOH/g or less the lubricant is considered inadequate for engine protection, and is at risk for allowing corrosion to take place. Higher sulfur fuel will decrease the TBN faster due to the increased formation of sulfuric acid.

Additional information

TAN (Total Acid number) is the inverse measurement of TBN. It is covered under ASTM D 664 and refers to the level of acid contamination caused by combustion.


* [ ASTM International]
* [ Noria Learning Centre article on TBN & TAN]
* [ Amsoil Comparative data]
* [ Mobileguard 550 Product Description]
* [ Castrol Cyltech 80AW data]

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Base Runs — (BsR) is a baseball statistic invented by sabermetrician David Smyth to estimate the number of runs a team should have scored given their component offensive statistics, as well as the number of runs a hitter/pitcher creates/allows. It measures… …   Wikipedia

  • Base pair — In molecular biology and genetics, the linking between two nitrogenous bases on opposite complementary DNA or certain types of RNA strands that are connected via hydrogen bonds is called a base pair (often abbreviated bp). In the canonical Watson …   Wikipedia

  • Total average — is a baseball statistic devised by sportswriter Thomas Boswell in the 1970s. The statistic is designed to measure a hitter s overall offensive contributions. The definition of the statistic is simple. A player gets a credit for every base he… …   Wikipedia

  • total — [tōt′ l] adj. [ME < MFr < ML totalis < L totus, all, whole < IE base * tēu , to swell > THUMB] 1. constituting the (or a) whole; entire; whole 2. complete; utter [a total loss] n. the whole amount or number; sum; aggregate vt.… …   English World dictionary

  • number symbolism — Introduction       cultural associations, including religious, philosophic, and aesthetic, with various numbers.       Humanity has had a love hate relationship with numbers from the earliest times. Bones dating from perhaps 30,000 years ago show …   Universalium

  • number — numberable, adj. numberer, n. /num beuhr/, n. 1. a numeral or group of numerals. 2. the sum, total, count, or aggregate of a collection of units, or the like: A number of people were hurt in the accident. The number of homeless children in the… …   Universalium

  • Base (mathematics) — In arithmetic, the base refers to the number b in an expression of the form b n . The number n is called the exponent and the expression is known formally as exponentiation of b by n or the exponential of n with base b . It is more commonly… …   Wikipedia

  • number — ▪ I. number num‧ber 1 [ˈnʌmbə ǁ bər] noun 1. [countable] a series of numbers used to identify someone or something: • He checked the number on the file. • Your account number is the last set of numbers on the bottom of your cheque. • Please quote …   Financial and business terms

  • Total bases — In baseball statistics, total bases refers to the number of bases a player has gained with hits, i.e. the sum of his/her hits weighted by 1 for a single, 2 for a double, 3 for a triple and 4 for a home run.Only bases attained from hits count… …   Wikipedia

  • Base rate fallacy — The base rate fallacy, also called base rate neglect or base rate bias, is an error that occurs when the conditional probability of some hypothesis H given some evidence E is assessed without taking into account the base rate or prior probability …   Wikipedia