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References:
AASHTO T 48-96
ASTM D 92-90
Flash and Fire test Method depends on definite rates of temperature increases to control the precision of the method. It is a non equilibrium method. Its primary use is for viscous materials giving a flash point of 79 and above. It is also used to determine fire point which is a temperature above the flash point temperature.
This test cover determination of the flash and fire points of all petroleum products except fuel oils and those having an open cup flash below 79 C.
Flash Point: Is a point which in a certain temperature surface of the test sample in the cup will flames suddenly due to heating and increasing the temperature. Duration of flashing of the test sample surface is very short ,it will happens suddenly.
Fire Point: Is a 5 seconds duration of burning and firing the sample due to increasing the heat temperature .it will happens after flashing time .
1. Flash and Fire Apparatus 2. Testing Cup, Heating Plate & Flame source
3.simple free air Heater 4.Termometer
Be sure to wear the protecting glass ,resisted cover and safety Gloves during the test, In order to avoid any injuries during the flashing and firing the bitumen.
For taking sample for this test it is normal to follow the instruction described in Bitumen Sampling Page, But it is important to insure that :
1. Don't put the sample in a plastic container 2.The sample does not contain any air bubles during
3.don't use the samples from a leaky container
4. Avoid to pouring the solid sample into cup, the sample must be completely fluidly before pouring to the cup
Be sure to put the instrument and the sample in a draft less room ,Also be sure to wash the instrument in order to remove any possible oil or dust inside the cup and firing device .
1. Fill up the cup from the heated sample and be sure to get the surface of the cup filled with bitumen be level and discard the extra amount of the sample which collected from cup edges.
2.Light (turn on) the flammable light and be sure that the diameter of the fire be 3.2-4.8 mm. turn on the heating device .put the cup on the top of the heating device . apply initially heating to the sample with 14-17 C /minute ,until it reaches to 56 C, Then decrease the heating ratio down to 5-6 C/minute.
3. apply the flame movement on the cup just 28 C before first assumed Flash point. the duration and the speed of the movement must be approximately each 2C increasing the temperature or passing a circle with 150mm radios ,continue this process until viewing the plash point.
4.record the Flashing Point and be sure to do not mix and confuse the true flash with bluish fire which some times occurs in upper face of the cup.
5.For Firing Point just continue the heating until seeing Fire on surface of the cup which is stable for 5 seconds. then Record this value as Fire point of the sample.
It is important to say that this test must be conducted in a normal air presure(101.3 Kpa) ,so if the barometer did not show this value use following formula for adjusting the values
Corrected value of flash or fire point= C + 0.033*(760-P)
Where C= observed temperature P= Barometer Pressure (mm Hg)
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