The specification for AdBlue aqueous urea solution is set to be incorporated into a new ISO standard in 2006, industry sources confirm.

Until now, the properties of AdBlue have been governed under the German DIN standard number 70070, and its specifications were developed and revised over a number of years. The latest configuration for the urea solution was finalised in August 2005 when formaldehyde content was reduced from 10 mg/kg to a total aldehyde content of 5 mg/kg. Also for the first time in August 2005 a limit was placed on aluminium content in AdBlue, the maximum value being 0.5 mg/kg.

"Ultimately, that makes the product more expensive"

European AdBlue producers and suppliers are forced to make certain adjustments when specifications are changed. Sources at SKW Piesteritz said the introduction of an aluminium limit reduces options for tranpsorting the solution. "Although the limit doesn't complicate production for us, it restricts tanking options for AdBlue to plastic or stainless steel. Ultimately that makes the product more expensive."

"Suppliers... may have to be more careful about their sources"

The reduction in aldehyde content is a further restriction to the grades of urea that can be used to produce AdBlue solution and is designed to eliminate the use of fertilizer grades, where aldehydes are present in anti-caking agents. This does not affect manufacturers able to produce special technical grades of urea for AdBlue, however, cautioned SKW, "suppliers who do not have a captive urea supply and are dissolving imported urea prills may find they have to be more careful about their sources."

Prior to DIN 70070 being transcribed into the ISO system, consultation is continuing between European industry experts under the auspices of FAKRA, the automotive standards committee of the DIN, but further changes to specifications are not expected.

"We think this is the final version of the DIN 70070 standard now, after so many years in development. It is very complicated to make changes once the ISO standard is in force," one source said. The ISO standard for AdBlue is expected to be in place by Autumn 2006. It will be identical to the current DIN 70070 and will replace it altogether. At the same time, standard ISO symbols for AdBlue will be formalised.