D56_9 (16a) (1)
0 (0 Likes / 0 Dislikes)
Using a graduated cylinder and
taking care to avoid wetting
the cup above the
final liquid level,
measure 50 plus or minus 0.5
milliliters of the sample
into the cup, both the sample
and graduated cylinder being
pre-cooled when necessary so
that the specimen temperature
at the time of measurement will
be 27 plus or minus 5 degrees
Celsius, 80 plus or minus
10 degrees Fahrenheit,
or at least 10 degrees
Celsius, 18 degrees Fahrenheit,
below the expected flash point--
whichever is lower.
It is essential that
the sample temperature
be maintained at least 10
degrees Celsius, 18 degrees
Fahrenheit, below the
expected flash point
during the transfer from
the sample container
to the cylinder and from the
cylinder to the test cup.
Destroy air bubbles on the
surface of the specimens
by use of knifepoint or
other suitable device.
Wipe the inside of the
cover with a clean cloth
or absorbent tissue paper.
Then attach the cover with a
temperature measuring device
in place to the bath collar.
Light the test flame.
When used, adjusting
it to the size
of a small bead on the
cover, operate the mechanism
on the cover in such a manner
as to introduce the ignition
source into the vapor
space of the cup.
And immediately
bring it up again.
The time consumed for
the full operation
should be 1 second,
allowing equal time periods
for the introduction and return.
Avoid any hesitation
in the operation
of depressing and raising
the ignition source.
When a flash is observed
on the initial operation
of the mechanism,
discontinue the test
and discard the
result. In this case,
a fresh sample shall be
cooled an additional 10
degrees Celsius, 18
degrees Fahrenheit,
below the original specimen
installation temperature.
Exercise care when
using a test flame.
If the flame is extinguished,
it cannot ignite the specimen,
and the gas entering the vapor
space can influence the result.
When the flame is
prematurely extinguished,
the test shall be discontinued
and any result discarded.
When the flash
point of the sample
is known to be below
60 degrees Celsius,
140 degrees Fahrenheit,
apply and adjust the heat so
that the temperature
of the portion
will rise at a rate
of 1 degrees Celsius,
2 degrees Fahrenheit,
per minute, plus or minus
6 seconds.
When the temperature of the
specimen in the test cup
is 5 degrees Celsius, 10 degrees
Fahrenheit, below its expected
flash point, apply
the ignition source
in the manner just described
in 9.2 of the written standard.
And repeat the application
of the ignition source
after each 0.5 degrees
Celsius, 1 degrees Fahrenheit,
rise in temperature
of the specimen.
If the flash point
of the sample is
known to be 60 degrees Celsius,
140 degrees Fahrenheit,
or higher, apply and
adjust the heat so
that the temperature
of the specimen
will rise at a rate
of 3 degrees Celsius,
5 degrees Fahrenheit per
minute, plus or minus 6 seconds.
When the temperature of the
specimen in the test cup
is 5 degrees Celsius, 10 degrees
Fahrenheit, below its expected
flash point, apply
the ignition source
in the manner just described
in 9.2 of the written standard.
And repeat the application
of the ignition source
each 1 degrees Celsius,
2 degrees Fahrenheit,
rise in temperature
of the specimen.
When the application
of the ignition source
causes a distinct flash in
the interior of the cup,
as defined in 3.1.1 of
the written standard,
observe and record the
temperature of the specimen
as the flash point.
Do not confuse the true flash
with the bluish halo that
sometimes surrounds the ignition
source during applications
immediately preceding
the actual flash.
Warning, for certain
mixtures containing
halogenated hydrocarbons,
such as methylene chloride
or trichloroethylene, no
distinct flash as defined
is observed.
Instead, a significant
enlargement
of the test flame,
not halo effect,
and change in color of the test
flame from blue to yellowish
orange occurs.
Continued heating and
testing of these samples
above ambient temperature can
result in significant burning
of vapors outside
the test cup and can
be potential fire hazards.
See Appendix X1 and appendix
X2 of the written standard
for more information.
Discontinue the test and
remove the source of heat.
Lift the lid and
wipe the temperature
measuring device bulb.
Remove the test cup,
empty, and wipe dry.
If at any time between the first
introduction of the ignition
source and the observation
of the flash point
the rise in temperature
of the specimen
is not within the specified
rate, discontinue the test,
discard the result,
and repeat the test,
adjusting the source
of the heat to secure
the proper rate of
temperature rise,
or using a modified
expected flash
point, or both, as required.
Never make a repeat test on
the same specimen of sample.
Always take fresh specimen
of sample for each test.