The production, handling and transportation of Diesel Exhaust Fluid (DEF) are governed by the ISO 22241 standard. The standard covers five main points:
1 Urea concentration: DEF must have a urea concentration of 32.5% by weight. This concentration was selected because it is has the lowest freezing temperature, 12°F (-11°C).
2 Contamination: Contaminated fluid can damage SCR injectors and catalysts, resulting in system malfunction or failure. Therefore, the maximum level of impurities permitted in DEF, such as calcium and various metals such as iron, copper, zinc and aluminum, are clearly specified. There limits are set very low. For example, a spoon of table salt in a DEF tote would push the sodium content far above the ISO 22241 limit of 0.5 ppm.
3 Quality: ISO 22241 excludes the use of urea granules used as fertilizer in agriculture, and requires water purified by distillation or de-ionization.
4 Materials: Only certain materials are permitted for the storage and handling of DEF. DEF is corrosive to many materials, including carbon steel, copper and aluminum, which cannot be used. The main risk of using incorrect materials with DEF is that the DEF will be contaminated by the material, resulting in damage or failure of the SCR system on your truck.
5 Handling guidelines: Guidelines require manufacturers to follow clear procedures for the manufacture and distribution of DEF, ensuring that the product you use meets the the requirements of vehicle manufacturers.
The ISO standards are available for purchase for a small fee from the ISO website.
• What is DEF?
• How SCR works
• Emissions Regulations
• Frequently Asked Questions
• Glossary
• Links
The American Petroleum Institute (API) runs a voluntary program for certifying DEF producers and distributors through its Diesel Exhaust Fluid Certification Program. Suppliers who have been approved by the API display its logo on their DEF products, guaranteeing the quality of your purchase and its suitability for proper SCR operation. API takes random samples in the market to ensure DEF quality. All DEF marketers listed on www.discoverDEF.com are API certified.
