DEF for Industrial Applications

What is Diesel Exhaust Fluid (DEF)?

DEF is the main reactant and a critical element of Cummins Tier 4 Final Selective Catalytic Reduction (SCR) aftertreatment system.  DEF decomposes into ammonia and water within the SCR system where it reacts with and simplifies oxides of nitrogen (NOx) into nitrogen, carbon dioxide and water vapor.

DEF has a uniform composition of 32.5% urea and 67.5% pure water. This composition makes DEF:

  • Non-toxic
  • Non-flammable
  • Non-polluting
  • Consistent in low temperatures

DEF’s urea to water ratio is preferred for use with most SCR systems worldwide due to its optimum cold weather performance.  The 32.5% DEF concentration has the lowest freezing point of all possible concentrations (down to 12° F or -11° C) and enables the urea and water to freeze and thaw with a consistent concentration.

DEF consumption will vary depending on the environment, operation and duty cycle of equipment. On average, DEF consumption is 3% to 5% of fuel consumption. As fuel consumption increases, DEF consumption also increases, so it is important to consider the highest fuel consumption rates of the equipment when planning DEF delivery and storage.

Due to its wide availability throughout both North America and Europe, DEF is subject to multiple international quality standards.

Quality DEF should meet and display certification from the American Petroleum Institute (API), German Institute of Standardization DIN70700 or the International Organization of Standardization (ISO) 22241.

View the DEF Flyer for more information [PDF, opens in new window].