Flash Point:

At which temperature an organic compound grow out of its maximum vapor to ignite in the air is called flash point.

What is Flash Point of transformer oil?

At which minimum temperature the transformer oil gives of vapor to ignite in the air is called the flash point of transformer oil. Commonly the flash point of transformer oil/ insulating oil is 140 degree Celsius. Flashpoint is the physical parameter of transformer oil. Flashpoint test of transformer oil indicates the flammability of the substance or the organic compound.

Flashpoint test of transformer oil is a low-cost test and popular test of insulating oil. The oil sparkles after the mixing of vapor with oxygen in the air. The vapor pressure of oil normally in flash point is 3-5 mm Hg. When a small amount of flame is applied to the oil the mixture of vapor will burn for temporary and then it will get rid of automatically when the point temperature has been reached. If we continue the heating process for a long time or more than the flash point (50-70 degree Celsius) then the oil will be reached at the fire point.

Use of Flash Point to Detect Fuel Dilution:

The use of flash point is detected to determine the fire hazard of fuels and oil or transported. It can identify the volatility, narrowness and wideness of oil. Some mineral oils evaporate for a long time before the flash point of mineral oils reached and some synthetics do not evaporate until they started to decompose. Hence the range of synthetic is more than the mineral oils of refined viscosities. Flashpoint test of transformer oil can identify the abnormal level of fuel and the ability of an oil analysis programme. It can identify the fake conclusion on dilution of fuel from an original low viscosity.

Base oil cracking:

Sometimes, a high temperature can lead to split the gas evolution in the air for lowering the flash point. The miss-application of high watt-density can the main cause of thermal cracking. The process by which the air circulated through to dissolved with liquid or substance is called aeration. And hydraulic systems of aeration is subject to the high adiabatic temperatures when air bubbles are pressurized.

Standardized Flash Point Tests for Lubricants and oil:

Standardized flash point procedure is to sure the accuracy and quality of the flash point test instrument. There are different types of tests available for standardized flash point like: ISO, ASTM and IP. These three are commonly used for hydraulic fluids.

Cleveland Open Clove:

In this test, we need a metal container with full of transformer oil. Then heat the transformer oil at a prescribed rate. The oil will heat until a flash appears. Record the temperature of the oil as its flash point.

Pensky- Marten Closed Cap:

In this test, the transformer oil is closed in a container and heat in the pilot flame. The lubricant will distress during the heated period. After appearing of flash in the lowest temperature record the temperature.

Small Scale Closed Tester:

When Cleveland open clove and Pensky-Marten closed cap give the wrong result then the Small Scale Closed tester can give the right result to us by applying of the screening test with only 2 ml of fluid in just 1-2 minutes.


Flash Point is more important for the analysis of oil. Flash Point can give you the perfect record of the oil. And you can easily analysis the used oil in Flashpoint.