Handling Diesel Exhaust Fluid
January 2016
Now that the EPA’s final tier of emissions standards for diesel engines has come into effect, handling diesel exhaust fluid (DEF) is a reality in the daily maintenance of off-road machinery.
The Basics of DEF
It seems there is quite a bit of misinformation out there about DEF. Let's start with same basic facts.
DEF Contamination
Manufacturers of high horsepower diesel engines, specifically those in the 174-750hp range, are using Selective Catalytic Reduction (SCR) systems to meet the regulations.
SCR technology involves a process where DEF is injected into the engine exhaust. This produces a chemical reaction with nitrogen oxides, converting them to water and nitrogen.
In order for the SCR system to function effectively, it’s imperative that the quality of the fluid is maintained. DEF is sensitive to chemical impurities. Trace amounts of common elements can contaminate an entire tank of DEF.
Contaminated DEF poses some risk to your operation, as shown in the image above.
Maintaining Purity
The International Standards Organization has developed the ISO 22241 standard for how DEF is manufactured and how it should be handled. Preventing contamination in off-road environments takes a four-step approach:
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