standards, refer to ISO22241, which
details specifications for DEF quality,
handling, testing, transportation
storage, and refilling.
What is API Certification?
API Certification is a voluntary
program established by the
American Petroleum Institute
(API) which certifies and monitors
that diesel exhaust fluid meets ISO
specifications. The program was
launched in March 2009. Cummins
Filtration DEF currently meets ISO
specification and is also API certified.
Is the 32. 5 percent urea
Yes, The 32. 5 percent urea
concentration is the ideal solution as
it provides the lowest freeze point.
Also, SCR systems will be calibrated
to the 32. 5 percent, so that optimum
NOx (nitrogen oxide) will be reduced
What is the freeze point of DEF?
A 32. 5 percent solution of DEF
will begin to crystallize and freeze at
12 degrees F). At 32. 5 percent, both
the urea and water will freeze at the
same rate, ensuring that as it thaws,
the fluid does not become diluted,
or over concentrated. The freezing
and unthawing of DEF will not cause
degradation of the product.
Does DEF expand when frozen?
Yes, DEF expands by about 7
percent when frozen. DEF packaging
and tanks are designed to allow
How much does DEF weigh?
DEF weighs about nine pounds
How do I keep the DEF from
freezing? What happens if the
DEF freezes in the tank on
During vehicle operation, SCR
systems are designed to provide
heating for the DEF tank and supply
lines. If DEF freezes when the
vehicle is shut down, start-up and
normal operation of the vehicle will
not be inhibited. The SCR heating
system is designed to quickly return
the DEF to liquid form and the
operation of the vehicle will not be
impacted. The freezing and thawing
of DEF will not cause degradation
of the product.
Can an anti-gelling or freeze-point
product be added to the DEF to
prevent it from freezing?
No. While an additive could
improve freeze point of the mixture,
the 32. 5 percent solution is very
specific to providing Nox-reducing
properties. Any further blending
or adjusting of the DEF mixture
will impede its ability to perform
correctly and may cause damage to
the SCR components. Additives of
any type are not approved for use
in DEF today.
Are there special storage
requirements for DEF?
DEF should be stored in a cool,
dry, well-ventilated area, out of direct
sunlight. While the optimum storage
temperature is up to 77 degrees,
temporary exposure to higher
temperatures has little to no impact
on the quality of DEF.
What is the shelf life of DEF?
The shelf life of DEF is a function
of ambient storage temperature.
DEF will degrade over time
depending on temperature and
exposure to sun light. Expectations
for shelf life as defined by ISO
Spec 22241-3 are the minimum
expectations for shelf life when
stored at constant temperatures.
If stored between 10 and 90 degrees,
shelf life will easily be one year.
If the maximum temperature does
not exceed about 75 degrees for an
extended period of time, the shelf
life will be two years.
What impact will exposure to high
temperatures for an extended
period of time have on DEF?
While DEF exposure to constant,
high storage temperature may have
some impact on shelf life, this should
not concern operators. Extensive
testing in very hot climates has been
conducted confirming that DEF
stored at a constant temperature of
95 degrees had a shelf life of more
than six months.
Should I be concerned about
No. DEF is a nontoxic,
nonpolluting, non-hazardous and
nonflammable solution. It is stable,
colorless, and meets accepted
international standards for purity
and composition. DEF is safe to
handle and store and poses no
serious risk to humans, animals,
equipment or the environment
when handled properly.
What should I do if I spill DEF?
If DEF is spilled, contain the
spilled liquid and absorb it with an
inert, non-combustible absorbent
material, such as sand. Shovel the
material into a suitable container for
disposal. Spills into a drain should be
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