Diesel Exhaust Fluid (DEF)

Helping make a better world

Sapp Bros. Offers Complete DEF Solutions

Diesel Exhaust Fluid (DEF) is a product that’s helping to change the world we live and work in … for the better! DEF helps remove impurities from all diesel exhaust systems.

Sapp Bros. has been a distributor for several years and we have a good understanding of the changing rules and regulations surrounding this product. We provide several purchasing options for DEF including 2.5-gallon individual containers, drums and 275-gallon and 330-gallon totes.

Additionally, we can schedule delivery for any quantity of bulk DEF to be transported directly to your on-site storage.

All the DEF Equipment You Need

Sapp Bros. can also provide all the parts and dispensing equipment you may need for DEF delivery systems and maintenance. These include pumps, hoses, nozzles and tanks.

Frequently Asked Questions

If you don’t find the answer you’re looking for in the FAQs below, please call us at 855-DEF-TANK (855-333-8265).

General FAQs

Diesel Exhaust Fluid (DEF) in one of the key elements involved in the reduction of diesel engine emissions for engines equipped with Selective Catalytic Reduction (SCR) systems. It is a nontoxic solution of 67.5% De-inonized (de-mineralized) water and 32.5% automotive grade urea. DEF exhibits the following properties:

  • Non-toxic and non-polluting
  • Non-flammable
  • Stable and colorless
  • Non-hazardous
  • Does not require special handling

Exhaust Gas Recirculation (EGR) is a technique to reduce NOx emissions by recirculating a portion of an engine’s exhaust gas back to the engine cylinders. This technology has been adopted by both gasoline and diesel powered vehicles to meet increasingly stringent emission standards. The Diesel Particulate Filter (DPF) is a device which physically captures diesel particulates, preventing their discharge from the tailpipe. Collected particulates need to be removed from the filter, usually by continuous or periodic oxidation in a process called “regeneration.”

NOx is made of reactive gases, Nitrogen Oxide and Nitrogen Dioxide, created by burning fossil fuels such as coal, gas, and diesel. NOx contributes to acid rain and creates ground-level ozone (Smog). NOx can lead to nitric acid in the atmosphere, which can damage lung tissue and worsen diseases like asthma, emphysema, and bronchitis.

Urea is a compound of nitrogen that turns to ammonia when heated. It is used in a variety of industries, including agriculture as a fertilizer. DEF uses automotive grade urea which has a much higher purity than its agricultural counterpart. Using a lower-quality urea will cause degradation of the SCR system, eventually causing the engine to break down. In the short-term it may cause the sensors to believe the DEF tank is empty and prompt a deteriorating event, which reduces engine power and eventually prevents the engine from restarting.

Intermediate Bulk Containers (IBC) includes all containers larger than the pre-packaged 1, 2.5, and 5 gallon disposable plastic jugs and less than a tanker. In the early stages of distribution, 55 gallon drums and 275 or 330 gallon totes were the norm. More recently, convenient and durable self-contained IBC units of various sizes (55gal, 75 gal., and 100 gal.) are finding favor with DEF users. These smaller tanks contain the filling valve, pump, dispenser nozzle, hose, and power cord all in one ready-made unit, suitable for either primary storage or transport.

DEF Usage

No. Additives of any type are not approved for use in DEF today.

Indicators on the dash will alert the operator of the level of DEF in the tank. There will be a DEF low level warning lamp that will illuminate when DEF is low. If operation continues such that one would run out of DEF, the power will be dramatically reduced. Normal power levels will return once the tank has been refilled. The engine will shut-down if the DEF tank runs empty. Shut-down may require a service call from the dealer to restart the engine.

DEF should not react with windshield wiper fluids which are typically mixtures of ammonia and solvents (methanol), or anti-freeze fluids (ethylene glycol). There should not be any chemical reactions expected from interactions with automotive oils.

Engines utilizing a combination of technologies may use 2-4% of diesel consumption. Engines using SCR only may use up to 8-9% of diesel consumption. The engine usage of DEF varies greatly by how heavy the load or use; the heavier the load, the more demand for DEF.

DEF prices cover a wide range, depending upon availability, container quantity, and close proximity of bulk supplier. As the demand for DEF increases, competition will squeeze the margins. Savings of $1 to $1.50 can be achieved by moving from jug to IBC, providing a quick return on investment by purchasing a tank or tote. Additional savings may be attained by dealing in quantity with a reputable bulk supplier.

DEF is defined by AUS-32 specifications (aqueous urea solution), which meet or exceed the German Institute of Standardization DIN 70070, and the International Organization for Standardization ISO 22141-1. The American Petroleum Institute has developed a quality certification program that ensures North American supplies of DEF will meet these standards at the pump and across the nationwide supply chain, including standards of product manufacturing, handling, quality assurance, safety and environmental protection.

The catalysts used in the SCR after-treatment system consist of catalytically active transition metal compounds, which are fixed onto ceramic carriers. The width of the pores in the ceramic carrier influences the diffusion rate of the exhaust gases into the catalyst. To ensure a high activity of the SCR after-treatment system over a long period of time, the quality of AUS 32 has to be controlled very strictly, as many of the components with limit values, or contaminants, in ISO 22241-1 irreversibly harm the catalyst system by physical blocking of the pores, or deactivation of the reactive centers. Poor activity of the SCR system due to inactive catalysts may: 1. result in an increase in NOx emissions, and 2. cause secondary damage in the engine itself due to an exhaust gas pressure increase.

DEF mistakenly dispensed into the diesel fuel tank may be very harmful to the catalytic converter.

Only IBC’s with a functional RSV buttress valve can be refilled in a sealed system. IBC’s that have been openfilled may have a buttress valve inserted and be refilled, but they must first be cleaned with de-ionized water through an approved recycle facility. Open containers with a screw-off lid cannot be refilled from a bulk supplier such as Definite Advantage, Inc. Jugs of 1, 2.5 and 5 gallons are pre-packaged units and should not be reused. The use of tap water for cleaning purposes should be avoided due to the high concentrations of alkali and alkali earth metal ions present in the water.

It is not recommended that customers fill their own bottles of DEF for use in SCR systems due to the strict ISO requirements for maintaining DEF purity (free of contamination). The ISO 22241 specifications provide detailed information regarding DEF quality, handling, testing, transportation, storage, and refilling.

During 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 will not be inhibited. The SCR heating system is designed to quickly return the DEF to liquid form. DEF can be expected to increase 7% in volume when it freezes. DEF packaging and tanks are designed to allow for expansion.

DEF will begin to crystallize and become slush at 12 degrees F. 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.

DEF Storage

Not required. Vehicle on-board controls are designed to store and handle DEF.

DEF is not a fuel additive and never comes into contact with diesel. It is stored in a separate tank, typically with a blue filler cap. The filler necks of DEF tanks are smaller (19MM) than the nozzle used to dispense diesel (22MM), making it difficult to fill the DEF tank with diesel. The DEF tank cap is blue and clearly marked “Diesel Exhaust Fluid”. If diesel is dispensed into the DEF tank, shut-off the engine and contact your dealer immediately. Diesel is less dense than DEF and will float on top of the DEF in the tank, but even small amounts of diesel can damage your SCR system.

Contamination can cause clogged filters in the DEF tank, clogged nozzles in the SCR system, and possible damage to the catalytic converter. The greatest potential for contamination occurs when DEF is dispensed from a nozzle, either into an open-fill container or from a sealed container into the DEF tank on the vehicle or machine. Utmost care should be used in keeping filling ports and filler caps clear of contaminants. Urea is sticky and will attract airborne particles if exposed to the atmosphere. DEF will crystalize when exposed to air.

An open-fill system is one in which a lid is unscrewed from a container, a nozzle is inserted, and DEF is pumped into the container; the lid is screwed back on. A sealed system is one in which a 2” RSV buttress valve occupies the “opening” on the container, a filling hose with a male coupler is locked into place, forming a “seal” and DEF is pumped into the container; the DEF is never exposed to the air and the dispensing hose in uncoupled and removed. In a sealed system of dispensing, the product continues to be guaranteed for purity; in the open-fill system, warranty is lost, since it has been exposed to potential contamination.

The shelf life of DEF is a function of ambient storage temperature. Optimum storage temperature should not exceed 77 degrees F. DEF will degrade over time depending on temperature and exposure to sun light. DEF should be stored in a cool, dry, well-ventilated area, out of direct sunlight. If stored between 12 and 85 degrees F, shelf life can easily be one year. Under ideal conditions, shelf life may be expected to exceed one and one-half years.

If the temperature exceeds 95 degrees F for an extended period of time, hydrolysis will occur, forming ammonia and increasing pressure; shelf life may be reduced to six months. In cold temperatures, it is recommended to store DEF-IBC’s in a storage unit; in warm temperatures it is recommended to store DEF-IBC’s in a shaded area.

Urea is an excellent nutrient and will support organism growth. Prolonged direct exposure to sunlight should be avoided.

DEF Safety

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. For significant quantities, contact local authorities for proper disposal procedures. If DEF is spilled on your vehicle, rinse with water.

According to OSHA, DEF is mildly irritating to the eyes and skin. If the liquid should contact either, the DEF should be flushed out/washed off with plenty of clean water.

DEF should never be ingested. If it is ingested, do not induce vomiting. A physician should be consulted if you begin to experience any symptoms.

While pumping DEF will not cause significant exposure, inhalation may occur if exposed to DEF in a closed area and/or if DEF is misted into the air. 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.

No. By comparison, other automotive fluids such as diesel fuel, brake fluid, anti-freeze, transmission and engine oils are more toxic. The EPA classifies DEF as “non-hazardous”. Urea is naturally occurring and biodegradable.

DEF is corrosive to carbon steel, aluminum, copper, brass, and other alloys. Only approved materials, such as high density polyethylene (HDPE) or stainless steel will be used in the DEF tank, packaging and dispensing equipment.

No, aqueous urea is neither petroleum nor a hazardous substance. Although DEF may contain a small amount of ammonia, which is a regulated substance, it meets the designed minimum exclusion in the view of EPA.

Selective Catalytic Reduction (SCR)

There will be no changes to the lube filter service intervals on SCR equipped power units. The SCR process impacts the exhaust emissions after they are produced by the engine.

Even at market maturity in more than a decade, consumption of urea in DEF for all diesel vehicles (on-road cars and trucks, off-road vehicles) in developed countries will account for no more than 5% of world urea production. The use of SCR and DEF in developing countries such as China and India has substantial but uncertain potential.

Selective Catalytic Reduction (SCR) is an after-treatment technology that treats exhaust gas downstream of the engine and the Diesel Particulate Filter (DPF), should the engine be so equipped. A small quantity of DEF is injected into the exhaust upstream of the SCR catalyst, where it vaporizes and decomposes to form ammonia and carbon dioxide. When passed over the catalyst, the ammonia (NH3) converts the NOx components of the exhaust into harmless nitrogen (N2) and water vapor (H2O). This reaction does not result in any unusual or strange smells (rotten egg or chemical smell).

SCR technology was first patented in 1957 and has been used for many years to reduce NOx emissions from coalfired power plants. The technology was first used in vehicles by Nissan Diesel in Japan in 2004 to meet emissions standards that were the strictest in the world at that time. Since then SCR has been widely implemented in diesel vehicles. By the end of 2010, more than 1 million commercial vehicles were equipped with SCR emissions control technology in Europe alone.

Heavy duty engines utilizing SCR will provide substantial fuel economy improvement, up to 3-5% for highway vehicles and some reports of 5% and higher for off-road machines. SCR catalyst technology allows much greater NOx conversion efficiency, thereby allowing the engine to be fully optimized. Increasing the cylinder oxygen content can increase torque and lower engine particulate matter output. Less fuel is needed for Diesel Particulate Filter (DPF) cleanout, further reducing costs.

DEF is used in Selective Catalytic Reduction (SCR) systems to change the oxides of nitrogen (NOx) emissions in diesel exhaust to nitrogen and water. Nitrogen makes up about 78% of the air we breathe every day.

Miscellaneous FAQs

Yes. High quality DEF will be produced and distributed by companies that have demonstrated their domestic expertise in production and distribution and will bear the API Certified symbol. TerraCair is an ultra-pure, aldehyde-free DEF. With seven production facilities throughout North America, TerraCair carries the API certification of quality.

No, simply run the tank as empty as possible before refilling. DEF is a pure chemical, so your bulk storage tank never needs to be cleaned out unless it is contaminated by another substance.

Stainless steel and high density polyethylene (HDPE) are recommended materials for handling and storage. Most plastics are acceptable although Teflon tape should not be used for metal fittings. Sale of DEF through bulk dispensing is subject to weights and measures. DEF falls into the “Clear Liquid Fertilizers” product family of fluids for certification. When motor fuel is sampled, it is returned to storage. When DEF is sampled, it cannot be returned to storage; the risk of contamination is too great. Polyethylene or polypropylene tanks must be free of additives (white).

DEF weighs approximately 9 pounds per gallon.

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