We at Green Oil aim to inform you of any information that will be helpful in your business and our service to you. Below is a Q & A to hopefully answer some or all questions you may have about Diesel Exhaust Fluid.
SCR: The Leading Technology to Meet 2010 Emission Regulations
Q. What is Selective Catalytic Reduction (SCR)?
A. SCR is a technology that uses a urea based diesel exhaust fluid (DEF) and a catalytic
converter to significantly reduce oxides of nitrogen (NOx) emissions. SCR is the leading
technology being used to meet 2010 emission regulations.
Q. How does an SCR system work?
A. The purpose of the SCR system is to reduce levels of NOx (oxides of nitrogen emitted
from engines) that are harmful to our health and the environment. SCR is the
after treatment technology that treats exhaust gas downstream of the engine. Small
quantities of diesel exhaust fluid (DEF) are injected into the exhaust upstream of a
catalyst, where it vaporizes and decomposes to form ammonia and carbon dioxide. The
ammonia (NH3) is the desired product which in conjunction to the SCR catalyst, converts
the NOx to harmless nitrogen (N2) and water (H2O).
Q. What are the advantages for the fleet in using SCR technology?
A. Cummins 2010 engines will deliver what customers need in these challenging economic times.
Cummins 2010 heavy duty engines utilizing SCR will provide substantial fuel economy improvement, up
to 5%. SCR catalyst technology allows much greater NOx conversion efficiency, thereby allowing the
engine to be fully optimized, which contributes to this fuel economy improvement. Another benefit to the
improved fuel consumption is less frequent Diesel Particulate Filter (DPF) cleanout, thereby further
DEF: Properties & Handling Guidelines
Q. What is Diesel Exhaust Fluid (DEF)?
A. DEF is the reactant necessary for the functionality of the SCR system. It is a carefully blended
aqueous urea solution of 32.5% high purity urea and 67.5% deionized water.
Q. What is urea?
A. Urea is a compound of nitrogen that turns to ammonia when heated. It is used in a variety of
industries, including as a fertilizer in agriculture.
Q. How will I know that the DEF product I purchase will work?
A. The DEF you purchase should state and display the certification of the American Petroleum Institute
(API), German Institute of Standardization DIN70700, the International Organization for Standardization
ISO 22241-1, and meet AUS – 32 specifications. This will ensure the proper purity and concentration
(32.5%) of urea. For more information on these specifications, visit www.iso.org.
Q. Can I make DEF myself?
A. It is not recommend for customers make DEF themselves. DEF has strict
requirements for maintaining concentration and purity of ingredients that is critical to the proper
functioning and longevity of the SCR system. Cummins and other OEMs require that DEF used with their
SCR systems meet all ISO22241 specifications as well as API certification requirements. It is
recommended that end users purchase certified DEF and avoid blending it themselves. For more
information about the quality standards, refer to ISO22241 which details specifications for DEF quality,
handling, testing, transportation storage, and refilling.
Q. What is API Certification?
A. 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.
Q. Is the 32.5% urea solution critical?
A. Yes, The 32.5% urea concentration is the ideal solution as it provides the lowest freeze point. Also,
SCR systems will be calibrated to the 32.5%, so that optimum NOx will be reduced during operation.
Q. What is the freeze point of DEF?
A. A 32.5% solution of DEF will begin to crystallize and freeze at 12 deg F (-11 deg C). At 32.5%, 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
Q. Does DEF expand when frozen?
A. Yes, DEF expands by approximately 7% when frozen. DEF packaging and tanks are designed to allow
Q. How much does DEF weigh?
A. DEF weighs approximately 9 pounds per gallon.
Q. How do I keep the DEF from freezing? What happens if the DEF freezes in the tank on the vehicle?
A. 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 unthawing of DEF will not cause
degradation of the product.
Q. Can an anti-gelling or freeze point improver be added to the DEF to prevent it from freezing?
A. No. While an additive could improve freeze point of the mixture, the 32.5% 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. If the ISO standards should change to allow antifreeze additives,
Cummins Filtration will ensure our product continues to meet ISO requirements.
Q. Are there special storage requirements for DEF?
A. DEF should be stored in a cool, dry, well-ventilated area, out of direct sunlight. While the optimum
storage temperature is up to 77 deg F (25 deg C), temporary exposure to higher temperatures has little to
no impact on the quality of DEF.
Q. What is the shelf life of DEF?
A. 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 deg F, shelf life will easily be one year. If the maximum temperature does not exceed
approximately 75 deg F for an extended period of time, the shelf life will be two years.
Q. How can I determine when the DEF I have purchased was manufactured?
A. All DEF packages will have a date code located somewhere on the product. The date code will allow
you determine the date the DEF was made. 1 gallon containers will have a laser code imprinted on the
bottle. 2.5 and 5 gallon containers have a small date code label applied to the bottle. Drum and totes will
have a label applied to either the top or side of the product.
The first digit of the date code represents the DEF batch number and the next 6 digits reflect the date that
the batch was filled.
Q. What impact will exposure to high temperatures for an extended period of time have on DEF?
A. 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 deg F had a shelf life of over 6 months.
Q. Should I be concerned about handling DEF?
A. 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.
MSDS sheets are currently available on cumminsfiltration.com.
Q. What should I do if I spill DEF?
A. 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 avoided. If spilled into a drain, flush thoroughly with water. For significant quantities, contact local
authorities for proper disposal procedures. If DEF is spilled on your vehicle, rinse with water.
Q. What happens if I ingest DEF?
A. DEF should never be ingested. If it is ingested, do not induce vomiting. A physician should be
consulted if you begin experience any symptoms.
Q. What happens if I inhale DEF?
A. While pumping DEF will not cause significant exposure, inhalation may occur if exposed to DEF in a
closed area and/ of if DEF is misted into the air. Under normal conditions of use, harmful effects are not
expected. If you inhale DEF, you should move to an area with fresh air and obtain medical attention if symptoms, such as irritation to nose and throat, develop or persist.
Q. Does DEF smell?
A. DEF may have a slightly pungent odor similar to that of ammonia, however it is completely harmless.
Q. Is DEF corrosive?
A. DEF is corrosive to copper and brass as well as other materials. Only approved materials, such as
high density polyethylene (HDPE), will be used in the DEF tank, packaging and dispensing equipment.
Q. What measures have been put in place to prevent diesel from being pumped into the DEF tank?
A. The standard nozzle diameter for dispensing DEF has been designed at 19mm versus the standard
diesel fuel nozzle diameter which is 22mm. In addition, the tank cap for the DEF tank will be blue to
further differentiation from the diesel tank.
Q. What happens if a non-DEF substance is accidentally entered into the DEF tank?
A. The SCR system will recognize solutions other than DEF, and the DEF indicator light will appear
notifying the driver. Depending on the level of contamination in the tank, the vehicle may require
Q. How much DEF will a truck consume?
A. DEF consumption is expected to be approximately 2% of fuel consumption, depending on vehicle
operation, duty cycle, geography, load ratings, etc.
Q. What is the number of miles a truck can expect to travel on one gallon of DEF?
A. DEF consumption is directly related to fuel consumption. A truck averaging 6 MPG can expect to go
approximately 300 miles on one gallon of DEF.
Q. How can an operator determine how much DEF they will need/use?
A. DEF consumption will be approximately 2% of the diesel fuel consumed. Another way to consider it is
that DEF will be consumed on a 50 to 1 ratio with diesel. (For every 50 gallons of diesel fuel burned, you
will use 1 gallon of DEF). If you know the average fuel consumption of a vehicle, you can easily calculate
the amount of DEF that will be used.
Q. Is the DEF dose rate the same for all engine manufacturers?
A. The DEF dose rate will vary slightly amongst engine manufacturers. While most engines will have a
dose rate of 2% of diesel fuel consumed, the dose rate will range from 1% to 3%.
Q. What happens if the vehicle runs out of DEF?
A. Vehicles that use DEF will have indicators on the dash that will alert the driver of the quantity of DEF
on board. A gauge similar to a fuel gauge will indicate the level of DEF. There will be a DEF low level
warning lamp that will illuminate when DEF is low. If the vehicle is operated such that one would run
completely out of DEF, vehicle power will be reduced enough to encourage the operator to refill the DEF
tank. Once the tank has been refilled the engine will resume normal power levels.
Q. On SCR equipped vehicles, what changes will be expected for lube filter service intervals?
A. There will be no changes to the lube filter service intervals on SCR equipped vehicles. The SCR
process impacts the exhaust emissions after they are produced by the engine.
DEF Product Options & Availability
Q. What package sizes will be available? When?
A. 4 sizes: 55 gal drum, 275 gal disposable tote, 330
gal tote, and bulk. include 1, 2.5, and 5 gallon containers.
Q. Can I fill my own bottles of DEF?
A. It is not recommend that customers fill bottles of DEF for use in SCR systems due
to the strict ISO requirements for maintaining DEF purity (free of contamination). For customers that do
require filling, the ISO 22241 specifications provide detailed information regarding DEF quality, handling,
testing, transportation storage, and refilling.
Q. What does IBC stand for?
A. Intermediate Bulk Containers (IBC) are all containers larger than a 55 gallon (207L) drums, and
smaller than a tanker.
Q. Where will DEF be available?
A. In North America, all major truck stops have committed to carrying and selling DEF. The initial supply
of DEF will most likely be in packaged containers while bulk dispensing options are being installed.