What is Diesel Exhaust Fluid. In order for something to be called a Diesel Exhaust Fluid (DEF) the product must meet the following criteria:
Must meet ISO 22241—Which is an international standard that defines the quality requirements for DEF including production, storage and distribution. The production, handling and transportation of DEF is governed by the ISO 22241 standards. The key points are:
Diesel Exhaust Fluid (DEF) must have a urea concentration of 32.5% by weight. This concentration was chosen because it is has the lowest freezing temperature, 12°F.
The maximum level of impurities such as calcium and various metals such as iron, copper, zinc and aluminum are clearly specified. These limits are extremely low, to ensure reliable operation of the SCR system.
This definition excludes the use of urea grades used in agriculture, and requires water purified by distillation or deionization or similar.
IF a product does not adhere to the ISO 22241 standards, then that fluid cannot by definition be called a Diesel Exhaust Fluid (DEF). With a growing market there will be more and more unlicensed products to hit the streets calling their product DEF but it will simply be a urea solution. The only reason why a product would be unlicensed would likely be that it wouldn’t meet the ISO and API standard for DEF.

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