Flash
and Fire point test is a safety test conducted on a bituminous material so that
it gives an indication of the critical temperature at and above where
precautions should be taken to eliminate fire hazards during its applications.
Bituminous materials leave out volatiles at high temperature depending upon
their grade. These volatile vapors catch fire causing a flash. This condition
is very hazardous and it is therefore essential to qualify this temperature for
each bitumen grade, so that the paving engineers may restrict the mixing or
application temperature well within the limits. Flash and Fire point test is conducted
as per IS: 1209.
As per IS: 1209 the definitions of flash and fire point
are:
Flash Point: "The flash point of a material is the
lowest temperature at which the vapour of substance momentarily takes fire in
the form of a flash under specified conditions of test".
Fire Point: "The fire point is the lowest
temperature at which the material gets ignited and burns under specified
condition of test".
Aim: To determine
the flash and fire point of a given bituminous material.
Apparatus: Pensky-Martens
closed cup tester, thermometer, heating source, flame exposure.
Procedure:
1.
All parts of the
cup are cleaned and dried thoroughly before the test is started.
2. The material is
filled in the cup upto a mark. The lid is placed to close the cup in a closed
system. All accessories including thermometer of the specified range are
suitably fixed.
3.
The bitumen sample
is then heated. The test flame is lit and adjusted in such a way that the size
of a bed is of 4mm diameter. The heating of sample is done at a rate of 5° to
6°C per minute. During heating the sample the stirring is done at a rate of
approximately 60 revolutions per minute.
4. The test flame is
applied at intervals depending upon the expected flash and fire points and
corresponding temperatures at which the material shows the sign of flash and
fire are noted.
Observations: -
TABLE 4.4: - Observations of Flash Point of
bitumen sample taken
|
Test
|
Trial 1
|
Trial 2
|
Trial 3
|
Mean value
|
|
Flash Point ( 0C )
|
253
|
251
|
250
|
251.33
|
Result: The
temperature at which the flame application that causes a bright flash 251.330C.
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