Technical Terminology

These descriptions are general in nature and may not be absolutely technically correct.

A

Acid Number or Total Acid Number
– is a measurement of the acidic properties of an oil. The acid number of an oil increases during the service life of the oil due to acid build-up in the oil.

AGMA
– American Gear Manufacturers Association

Anti-wear Additive
– is an additive used to reduce the amount of wear between two sliding surfaces by reacting with the metal surface to form a film. Zinc (dialkyl dithiophosphate) is the most common type
used.

API
– American Petroleum Institute

Ash or Sulphated Ash
– is an measurement of the residue left behind after the combustion of an oil. Metallic (calcium and magnesium) detergents and (zinc) antiwear additives contribute to the ash content of an oil.

ASTM
– American Society for Testing and Materials. This group establishes many of the test methods used by laboratories to evaluate oils and greases.

Autoignition Temperature (AIT)

– is the temperature to which an oil can be heated before it will spontaneously ignite, even without a source of ignition. The AIT will occur at a higher temperature than the flash point or fire point of an oil.

B

Base Number or Total Base Number
– is a measure of the basic or alkaline properties of an oil. The base number of an oil decreases during the service life of an oil due to the consumption of some of the additives in the oil.

Base Oil or Base Stock
– is the lubricating oil portion of a lubricating oil or grease. It may be mineral (refined from crude oil) or synthetic (manufactured, chemically altered).

Brookfield Viscosity
– a low temperature viscosity used to evaluate hydraulic oils and gear oils.

C

CCS
– Cold Cranking Simulator, is a low temperature viscosity used to evaluate the start-up performance of motor oils.

Centistoke
– (cSt) A common unit of kinematic viscosity. Equal in value to a mm2/s.

Centipoise
– (cP) A common unit of absolute or dynamic viscosity. Results from Brookfield, Cold Cranking Simulator and Mini Rotary viscometers provide results in centipoise. Equal in value to a milli Pascal second (mPa.s).

CGSB
– Canadian General Standards Board, establish standard laboratory test methods for Canada.

Channel Point
– is the lowest temperature at which an oil will slump back into a channel cut through the oil. It is used to simulate gear teeth moving through cold oil.

COC
– Cleveland Open Cup Method, used for lubricating oils.

Compounded Oil
– is a lubricating oil containing fatty (natural or synthetic) additives.

D

Demulsibility
– is the ability of an oil to allow water to separate (drop-out).

Dropping Point
– is the highest temperature to which a grease can be heat before a drop of oil separates (and drops) from the grease (under prescribed conditions).

E

EP –Extreme Pressure
– is a term used to describe an oil or grease which contains an additive used to protect metal surfaces from heavy loading and shock loading by reacting with the metal surface to reduce the potential damage. Common in gear oils and multipurpose greases.

F

Four (4) Ball Test
– 4 Ball Wear test measures the wear protection provided by a lubricant by measuring a scar diameter on four steel balls. A smaller scar diameter indicates better wear protection.

4 Ball EP

- test measures the extreme pressure load carrying capacity of a lubricant. A higher load causing the welding of the balls (Weld Load) and a higher calculated Load Wear Index (LWI), determined prior to welding, indicate better EP protection.

Flash Point
– is the lowest temperature at which an oil creates enough flammable vapour to ignite in the presence of a spark, but not sustain a flame.

I

ISO
– International Standards Organization

L

Lubricant
– an oil or grease or solid used to reduce friction between two moving surfaces in contact.

M

Mineral Oil
– is base oil (or base stock) derived directly from crude oil at a refinery. The crude oil is cleaned-up by various solvent extraction, hydrofinishing, hydrotreating and dewaxing processes and separated into different viscosity grades.

MRV
– Mini Rotary Viscometer, is a low temperature viscosity used to measure the ability of an oil to be pumped within an automotive engine. It is used to prevent oil starvation during engine start-up.

N

Neutralization Number
– is another term used to refer to either the acid number or base number of an oil.

NLGI
– National Lubricating Grease Institute.

P

PMCC
– Pensky-Martens Closed Cup Method, used for fuel oils and lubricants containing lighter solvents.

Penetration
– is used to determine the NLGI grade number (the hardness or stiffness) of a grease e.g. a #2 grade grease.

R

R&O
– is an oil containing primarily just a rust and oxidation inhibiting additive package. It may contain an antifoam additive but will not contain an antiwear or EP additive.

S

SAE
– Society of Automotive Engineers.

Solvent Extraction
– a refining process for mineral base oils that is used to remove undesirable chemical components.

STLE
– Society of Tribologists and Lubrication Engineers.

Sulphated Ash
– See Ash.

Synthetic
– man-made, structurally altered (not naturally occurring) base oil. Various chemical types exist with different properties.

Synthetic Blend
– is a formulated lubricating oil containing both mineral oil base stock and synthetic oil base stock. The proportion of mineral oil to synthetic oil can vary widely.

T

TAGCC
– Tag Closed Cup Method, used for solvents

Timken OK Load
– is a measure of the extreme pressure (EP) properties of an oil or grease. The “OK Load” is the heaviest load that a film of lubricant can support without scoring under the test conditions. Test results can vary significantly.

Total Acid Number (TAN)
– See Acid Number determines how sour an engine oil gets during use towards the end of its lifespan. Determined in a laboratory environment often compared with TBN

Total Base Number (TBN)
– See Base Number is the number that shows how much lubricity still is in the used engine oil. Determined in a laboratory environment often compared with TAN