D7501_11
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Place 300 milliliters of sample
in a 500-milliliter glass
bottle, and set it
in a liquid or air
chamber at 4.5 plus or minus
0.5 degrees Celsius or 40
plus or minus 1 degree
Fahrenheit for 16
plus or minus 0.25 hours.
A refrigerator is not
suitable for this procedure.
After the 16-hour cold soak at
4.5 plus or minus 0.5 degrees
Celsius or 40 plus or minus 1
degree Fahrenheit is completed,
remove the sample from bath, and
place it in a circulating water
bath with the temperature
set to 25 plus or minus 0.5
degrees Celsius or 77 plus
or minus 1 degree Fahrenheit,
according to section 11.2.1 or
11.2.2 of the written standard.
The sample shall be completely
liquid before filtration.
If the sample is completely
liquid after the 16-hour cold
soak, heat the sample
at 25 plus or minus
0.5 degrees Celsius or 77 plus
or minus 1 degree Fahrenheit
for 2 plus or minus 0.25 hours.
Otherwise, follow section
11.2.2 of the written standard.
If the sample is solid or
contains any solids or haze
after the 16-hour cold
soak, heat the sample at 25
plus or minus 0.5 degrees
Celsius or 77 plus or minus
1 degree Fahrenheit for 4
plus or minus 0.25 hours.
Verify that the sample
is at 25 plus or minus
0.5 degrees Celsius or 77 plus
or minus 1 degree Fahrenheit
by dipping without
stirring or agitating
the sample with an RTD
sensor or thermometer.
Filter these samples as quickly
as possible upon removal
from the warming bath
once the desired warming
time has elapsed according
to section 11.2.1 or 11.2.2
of the written standard,
whichever applies.
Complete assembly
of the receiving
flask, 0.7 micrometer
glass fiber
filter, and funnel as a unit--
see figure 1 of the
written standard--
before swirling the sample.
To minimize operator
exposure to fumes,
the filtering procedure may
be performed in a fume hood.
Start the vacuum system.
The vacuum controls
have to be preset to run
the test correctly.
Since vacuum cannot be
achieved with an open filter,
a dry run with biodiesel may be
used to set the controls when
manual needle valves and
analog gauges are used.
Automatic digital
vacuum controllers
can be used to preset the
final vacuum pressure.
Thoroughly clean the outside
of the sample container
in the region of
the cap by wiping it
with a damp, lint-free cloth.
Swirl the container for
about 2 to 3 seconds
to dislodge any particles
that might have adhered
to the walls of the container.
Take care not to shake
the sample vigorously
after the cold soak, as this
could cause some of the solids
to go back into solution.
Immediately after
swirling, remove cap
and pour the entire contents
of the sample container
into the filtration funnel and
simultaneously start the timer.
The entire contents of
the sample container
shall be filtered through
the glass fiber filter
to ensure a correct measure
of the contamination
in the sample.
The entire contents of
the sample container
is defined as everything that
will flow out of the sample
container when it is poured
into the filtration funnel
and held for 10 seconds
after the bulk of the sample
has been poured out.
Record the vacuum in the
system within 1 minute
of starting the filtration.
The vacuum shall be between
70 to 85 kilopascals
or 21 to 25 inches of mercury.
If the vacuum is not
within the specified range,
make adjustments to
the vacuum system.
When filtration is
complete, as evidenced
by no sample remaining
on the filter,
immediately turn off
the vacuum system
and record the duration
of the filtration,
rounding to the nearest second.
If the filtration
is not complete
when 720 seconds or 12
minutes has elapsed,
turn off the vacuum
system, and record
the duration of the filtration
to the nearest second.
Record the pressure in the
system and the volume filtered
just before the termination
of the filtration.