Read the ISO 22241 Specifications for AdBlue®
Aqueous Urea Solution 32 Diesel Engine Fluid, more simply AUS 32 DEF, or better yet AdBlue® is manufactured to meet ISO 22241 standards in order to be compliant to be used in modern diesel engines.
AdBlue® is a registered trademark of the German Association of the Automobile Industry (VDA), our guide explains more about the emissions-reducing fluid.
ISO 22241 Specifications: Physical and chemical properties of AdBlue®
In order to be used in Euro 6 diesel engines, AdBlue® needs to meet the BS ISO 22241 specifications, which it does by having the required physical properties and chemical properties. The table below illustrates the properties AdBlue® needs to have.
| Parameter | Minimum | Maximum | Unit |
| Appearance | Colourless Liquid with slight ammonia odour | ||
| Freezing point | -11°C | -11°C | °C |
| Boiling point | 100°C | 100°C | °C |
| Basicity | 9 | 10 | pH |
| Flash point | not applicable (non-flammable) | ||
| Water solubility | 100 | g/l | |
| Viscosity at 20°C | 1.4 | 1.4 | mPa.s |
| Urea Content | 31.8 | 33.2 | % |
| Density at 20°C | 1.087 | 1.093 | g/cm3 |
| Refracting index at 20°C | 1.3814 | 1.3843 | |
| Alkalinity as NH3 | 0.2 | % | |
| Biuret | 0.3 | % | |
| Insolubles 20 mg/kg | 20 | mg/kg | |
| Aldehyde 5 mg/kg | 5 | mg/kg | |
| Phosphate (PO4) | 0.5 | mg/kg | |
| Calcium | 0.5 | mg/kg | |
| Iron | 0.5 | mg/kg | |
| Aluminium | 0.5 | mg/kg | |
| Magnesium | 0.5 | mg/kg | |
| Sodium | 0.5 | mg/kg | |
| Potassium | 0.5 | mg/kg | |
| Copper | 0.2 | mg/kg | |
| Zinc | 0.2 | mg/kg | |
| Chromium | 0.2 | mg/kg | |
| Nickel | 0.2 | mg/kg |
Download the AdBlue® Spec PDF here. All DEF supplied by Crown Oil meets the required standards.
If you have any other questions about AdBlue® or are looking for a supply from a trusted distributor, contact our Adblue® experts today on 0330 123 1444.
