Diesel Exhaust Fluid (DEF), also called Arla in Brazil, AdBlue in the non-North American region and AUS (Aqueous Urea Solution) 32 globally, is a colorless, non-hazardous, and non-flammable chemical. The fluid consists of 67.5% de-ionized water and 32.5% high purity automotive grade urea and when it comes into contact with skin can easily be washed off with water. DEF is a high quality liquid and as such sensitive to chemical impurities, it is essential that it is handled carefully to prevent contamination. DEF is much more likely to be damaged by the materials it touches than to cause damage to equipment, an ISO list regarding material to be used is available.
If DEF is contaminated it may cause the SCR system to malfunction. This means pumps and containers used for DEF must not be used for any other fluids. It is important that tanks, pumps, hoses and nozzles previously used for other products like diesel or lube oil are not used for DEF. The requirements for handling DEF are unique.
The DEF production process uses high quality grade urea (not to be confused with fertilizer-grade urea) and de-ionized water. When fertilizer grade urea and/or tap water is used the resulting fluid cannot be called DEF and will cause irreparable SCR damage and eventual catalyst failure.
The shelf life of DEF is usually two years if the fluid temperature remains between 12°F (-10°C) and 86°F (30°C). Where DEF is stored outside in bulk tanks or totes then heating and cooling solutions are available to ensure it is kept within the correct temperature range. Cooling is usually achieved by insulation and ventilation. Air conditioning is not required.
Certain stainless steels and various plastic materials are suitable for storing DEF. Carbon steels, copper, copper-containing alloys and zinc-coated steels should not be used. Contact your DEF supplier for a more comprehensive list of equipment and materials that are /are not recommended