FlashPoint (Open cup) and Fire point Test – Highway Engineering Lab

• THEORY: Bitumen is a volatile material and when temperature is increased, vapors are formed.

In order to work safely with the bitumen at the site, one must know the temperature at which bitumen may become hazardous to work with.

Flash and Fire points are the lowest temperature at which, sufficient amount of vapors are formed to catch the flash and fire respectively when a flame is brought near to it. At flash point sufficient amount of vapors are formed so as to catch a momentarily flash.

Flash and fire point vary for different variety of Bitumen. 

• PROCEDURE:

1. Heat up the bitumen sample to a pouring temperature and then pour it down into the cup up to the marking. Stir the bitumen properly to remove any foreign gases present.
2. Put the thermometer in place and start raising the temperature and 5 to 6 degrees per minute.
3. When the temperature is about 25 degrees Celsius near to the expected flash point, start the flame and bring it near to the vapors.
4. Note down the temperature at which the vapors catch a momentarily flash.
5. Now keep raising the temperature and note down the temperature at which fire is started.