Analytical Instrumentation

  • What is the Difference between Flash Point and Ignition Temperature?

What is the Difference between Flash Point and Ignition Temperature?

Jun 27 2014 Read 67424 Times

There are various methods and terms used for measuring the flammability and combustibility of a substance. Two of these terms are flash point and ignition temperature. Although they share similarities, they are very different terms.

Flash Point

The flash point is the lowest temperature at which a substance vaporises into a gas, which can be ignited with the introduction of an external source of fire. There are two main methods of measuring a flash point – namely, open cup and closed up.

Open cup flash point testing occurs when the substance is placed into a vessel which is open to the outside atmosphere. Its temperature is then gradually raised, and an ignition source is passed over the top of it at intervals. Once the substance “flashes” or becomes ignited, it has reached its flash point.

Closed cup flash point testing is conducted inside a sealed vessel and the ignition source is introduced into the vessel. As a result, the substance is not exposed to the elements outside of the vessel, which can have an interfering effect on the results of the test. This, in turn, also leads to lower flash points, because the heat is trapped inside. Because it is lower, the flash point is also safer for widespread use, and as such is more generally accepted.

To learn more about recent developments and advances in closed cup testing and their standards, read ASTM D7094 - Modified Continuously Closed Cup Flash Point Standard Accepted as a Safe Alternative Method in Various Fuel Specs.

Ignition Temperature

Unlike with flash points, the ignition temperature does not need an ignition source. In other words, the ignition temperature is the lowest temperature at which a volatile material will be vaporised into a gas which ignites without the help of any external flame or ignition source. As a result, the ignition temperature is of course higher than the flash point.

Typically, ignition temperatures are measured by placing the substance in a half-litre vessel and inside a temperature-controlled oven. The current standard procedures for such tests are outlined in ASTM E659.

It should be stressed, however, that both of these terms are not fundamental, unvarying properties belonging to the substances. Rather they are empirical results, gleaned through laboratory testing, which can vary according to the equipment used, the method chosen and the environment in which it is conducted.

Read comments1

Wasanta

Mar 16 2016

I read the article that '' Difference between Flash Point and Ignition Temperature". You have explained it clearly and in simple language. Thank you very much. Wasanta Abeyasekera.


Digital Edition

Petro Industry News September 2018

September 2018

In This Edition Fuel for Thought - New Partnership for the US Distributio - Element opens new oil and gas laboratory in Singapore - Metrohm Acquires B&W Tek Analytical Instrumentation...

View all digital editions

Events

NSC Conress & Expo

Oct 20 2018 Houston, USA

Offshore Energy 18

Oct 22 2018 Amsterdam, Netherlands

Oil & Gas

Oct 23 2018 Kiev, Ukraine

Waste and Recycling Expo

Oct 24 2018 Toronto, Canada

View all events