Diesel Exhaust Fluid (DEF) is a non-hazardous solution, which is 32.5% urea and 67.5% de-ionized water. DEF is sprayed into the exhaust stream of diesel vehicles to break down dangerous NOx emissions into harmless nitrogen and water. This system is called Selective Catalytic Reduction (SCR) and can be found on 2010 and later model year trucks and many diesel pickups and SUVs. DEF is not a fuel additive and never comes into contact with diesel. It is stored in a separate tank with a BLUE filler cap.

SCR technology uses a catalyst system to break down dangerous NOx emissions produced by diesel engines into nitrogen and water. The chemical reactions used in SCR systems require a constant feed of ammonia gas. In automotive applications SCR delivers ammonia using a urea solution called Diesel Exhaust Fluid (DEF). DEF is sprayed into the exhaust stream by an advanced injection system and then converted into ammonia through a special catalyst. The ammonia breaks down dangerous NOx emissions produced by diesel engines into nitrogen and water.

Diesel Exhaust Fluid (DEF) consumption is measured as a ratio of diesel fuel use, normally termed the “dosing rate”. Light, medium and heavy-duty vehicles have a dosing rate of approximately 3-3.5% depending on the engines work load. This means that if your truck has a hundred-gallon tank of fuel you will consume approximately 3 percent of the tank capacity.

The price of Diesel Exhaust Fluid (DEF) varies and will depend on the UREA market, blending, transportation and the volume of fluid and service that you require.

Packaging is supplied, in quantities of 2.5 gallon jugs, 55 gallon drums, 330 gallon totes or Florida’s DEF’s specialized Truck 2 Truck™, fluid replenishment service on your site.

The U.S. Environmental Protection Agency requires vehicle manufacturers to put measures in place to ensure that vehicles cannot run without Diesel Exhaust Fluid (DEF). Before a truck’s DEF tank runs empty the driver is given a series of alerts on their dashboard displays (much the same way as if they were running low on diesel). When the DEF tank level drops below 10%, a gauge and/or warning light will be displayed.

There is a small margin of error and the truck can be driven a few miles, but if allowed to run out of DEF, the engine’s power will be reduced. A solid red warning will be displayed and the vehicle speed will be limited to 5 mph until the DEF tank is refilled.

The filling cap for the DEF tank is blue and will be clearly marked ‘Diesel Exhaust Fluid’ with the accompanying ISO standard number.

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 and Florida DEF recommends that you do not attempt to empty or drain the DEF out of the tank. You should contact your dealer or service provider immediately and do not drive the vehicle. If you have in-house technicians, and try to clean the DEF tank yourself, remember that diesel will float, and should be vacuumed out from the top and not the bottom of the tank. If the sensors get coated with diesel fuel and are not properly cleaned, continuous expensive issues will result.

DEF is denser than diesel and will sink to the bottom of the tank and be drawn into the fuel system. Even small amounts of DEF can damage your fuel system and Florida DEF recommends that you do not attempt to drive, empty, drain or run the engine. Tow the vehicle to the dealer or service provider immediately and fully explain the situation.

If you have in-house technicians, and try to clean the fuel tank yourself, remember that DEF will sink to the bottom and should be drained or vacuumed out from the bottom and not the top of the tank. Florida DEF does not recommend inexperienced people attempting to correct this situation.

If DEF is dispensed into the diesel tank, the engine will stop running almost immediately, and the repairs could be in excess of $10,000 if the engine is operated.

Selective Catalytic Reduction (SCR) is the technology of choice for all truck and engine manufacturers to meet the U.S. Environmental Protection Agency’s 2010 emissions standards for medium and heavy-duty vehicles. The truck manufacturers concluded that the only way to meet these rules without compromising engine performance and fuel efficiency was to use SCR as Europe has done for many years.

Selective Catalytic Reduction (SCR) technology was first patented in 1957 and has been used for many years to reduce NOx emissions from coal-fired power plants and other stationary sources. The technology was first used in series production in diesel 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 implemented worldwide on diesel vehicles and by the end of 2019 millions of commercial vehicles as well as locomotives and boats will be equipped with SCR emissions control technology.

Diesel Exhaust Fluid (DEF) is not toxic, harmful or dangerous. In fact, of all the fluids used in a truck, such as diesel, engine oil, brake fluid, antifreeze and windshield wash, it is the least hazardous. DEF is corrosive however for some metals such as carbon steel, aluminum, copper and zinc, and should not be stored in containers made of these materials. As your supplier, Florida DEF can advise you further. ISO22241

Wearing protective clothing is not necessary when handling DEF, however, Diesel Exhaust Fluid is slimy and (DEF) can stain clothes or shoes. If you do spill any DEF on your clothing, rinse it off with water. Florida DEF does advise the use of gloves and safety goggles for additional protection.

OSHA requirements do apply to any person dispensing DEF. Florida DEF suggests becoming familiar with the OSHA rules and how they may affect your company.

If you spill a small amount of Diesel Exhaust Fluid (DEF), it can be washed away with plain water. If you leave it to dry it will turn into white crystals. These can be washed away with plain water.

Diesel Exhaust Fluid (DEF) has a shelf life of two years. However, this can be reduced if the fluid is exposed to direct sunlight or if the temperature of the DEF remains above 86°F (30°C) for sustained periods. All DEF packaging should be labeled with an expiration date. If you have DEF that is beyond its expiration date dispose of it, or it can be diluted with water at a ratio of 1:10 and used on your lawn as fertilizer.

Diesel Exhaust Fluid (DEF) freezes into a crystalline slush at 12°F (-11°C). If DEF freezes in your vehicle, overnight or over a weekend, you do not need to take any action. Use the vehicle as you normally would. Truck manufacturers use a variety of heating methods to thaw frozen DEF tanks, including in-tank heating elements. While the thawing process is taking place the vehicle’s performance will not be affected (the amount of DEF used will be reduced because a cold engine produces a low level of NOx emissions). In some cases, the DEF supply tubes are also heated to prevent freezing or the tubes are emptied once the engine is turned off. In short, there is no reason to be concerned about using your SCR truck in cold weather.

Diesel Exhaust Fluid (DEF) uses automotive-grade urea, which has a much higher purity than fertilizer urea. Using a lower-quality fertilizer urea will cause degradation of the Selective Catalytic Reduction (SCR) system, eventually causing the truck to break down. In the short-term it may also cause the sensors to believe the truck’s DEF tank is empty and prompt a de-rating event, which reduces engine power and eventually prevents the engine from restarting.

Diesel Exhaust Fluid (DEF) should not be swallowed. If ingested, a physician should be consulted immediately. Follow all company procedures in place and when in doubt go to the hospital emergency room.

Under normal conditions of use, inhalation is not expected. However, when pumping large amounts Diesel Exhaust Fluid (DEF) in a closed area it is possible that inhalation of a small quantity of ammonia fumes from DEF might occur.

If you do inhale these fumes from DEF, move to an area of fresh air. A physician should be consulted if you experience any continued symptoms, such as irritation to nose or throat. DEF does sometimes have a slight ammonia smell (similar to home cleaning agents), but these are not harmful.