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The Do's and Don'ts of DEF

For 2014, diesel exhaust fluid (DEF) is going to be the norm for high-horsepower diesel engines,” says Luke Van Wyk, of Thunder Creek Equipment. “That means the pickups you drive, the semis you drive, the school buses your kids ride on, your tractors, your construction equipment – it’s all going to use DEF now. We need to learn what it is and how we are going to handle it efficiently, safely, and contaminant-free.”

Why DEF?
Equipment manufacturers are using selective catalytic reduction (SCR) to meet Tier 4 final emission standards. This technology injects DEF into the diesel engine exhaust system to achieve the necessary emission reduction by breaking down particulate matter and nitrogen oxide. 

DEF is 32.5% synthetic urea and 67.5% de-ionized water. The good news is that DEF is:

  • Nontoxic
  • Nonpolluting
  • Nonflammable
  • Nonhazardous
  • Stable
  • Colorless

The downside is that because DEF is nitrogen-based, it’s corrosive to most metals and coatings. DEF is more susceptible to contamination than other fluids. 

“As little as one tenth of a teaspoon of some common elements can contaminate a 5,000-gallon tanker of DEF,” explains Van Wyk. 

When DEF is contaminated it:

  • Increases DEF consumption.
  • Is less effective at removing emissions.
  • Can cause the SCR system to malfunction.
  • Can cause the engine to shut down.
  • Can damage the equipment.
  • Can void a manufacturer’s warranty.

Careful handling is key
To ensure that DEF works properly, you want a closed, sealed system so you aren’t introducing contaminants into the fluid. 

With Thunder Creek Equipment’s fuel trailers, you use a closed-loop coupler (which is the industry standard), hook this up to the source of DEF, and pull DEF from the source into the tank. Then you reverse the flow, put the nozzle on the end of the hose, and push the fluid into the end-use equipment. 

“This helps you to stay compliant and to reduce downtime and the negative effects, including shutdowns and increased consumption,” says Van Wyk. “It also eliminates the need to purchase a separate DEF-approved transfer pump.”

ISO developed a standard (22241) that outlines the procedures and quality standards for the systems handling and dispensing DEF. Make sure that the tank or trailer you use follows these standards.

How much?
Your DEF use can be from 2% to 12% of your fuel consumption, depending on the application and the environment. 

If you are using a tractor or combine, you could use 200 to 400 gallons of fuel a day. Your DEF consumption could be anywhere from about 5 to 50 gallons. “The consumption is enough that you will have to think about how to effectively and safely handle DEF,” says Van Wyk.

3 final facts
Here are three facts about DEF you should know.

  • DEF is good for two years, unless it’s exposed to direct sunlight or to prolonged temps above 86°F.
  • DEF is capable of freezing. Freezing doesn’t hurt DEF, but frozen DEF can burst a closed container. A heater option is available  for prolonged exposure to temperatures below 12°F.
  • DEF is capable of evaporating. That’s another reason why containers should always be closed securely.

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