A 40% high-purity urea solution for marine SCR engines, manufactured to the same certified quality standards as our AdBlue®.
AUS 40 is a 40% aqueous urea solution used in marine Selective Catalytic Reduction (SCR) systems to reduce NOx emissions from marine diesel engines. It works on the same principle as AdBlue® (AUS 32) but at a higher concentration suited to marine applications.
The higher 40% urea concentration is specified by many marine engine builders because it delivers more reactant per litre — reducing on-board storage volume and refill frequency on long voyages — while helping vessels meet IMO Tier III NOx limits in designated Emission Control Areas. It is dosed into the exhaust stream ahead of the SCR catalyst, where it converts harmful nitrogen oxides into harmless nitrogen and water.
Because SCR systems are sensitive to contamination, purity and concentration matter. We manufacture AUS 40 in our own Australian facility using the same high-purity feedstock and quality controls as our certified AdBlue®, and lab-test every batch for concentration and purity with full traceability — so what reaches your tank is consistent, batch after batch.
Manufactured in our own Australian facility, blended and lab-tested for purity and concentration, with full batch traceability — supplied in bulk tanker deliveries.
| Format | Best for |
|---|---|
| AUS 40 — 1,000 L IBC | Smaller vessels & top-ups |
| AUS 40 — Bulk (tanker delivery) | On-site & dockside storage, typically 20,000–32,000 L |
We deliver bulk AUS 40 in tanker loads, direct to your storage tank or dockside facility — most orders fall between 20,000 and 32,000 litres. Tell us your volumes and location and we'll organise supply and scheduled delivery to suit your operation.
Full manufacturing specification for our 40% marine-grade urea solution — urea content, density, refractive index and trace-metal limits, made and lab-tested to these values in Australia.
Download PDFBoth are urea in demineralised water, and both feed an SCR system, but they are made to different concentrations and different standards. Always use the solution your engine or SCR maker specifies.
| AdBlue® (AUS 32) | AUS 40 | |
|---|---|---|
| Urea content | 32.5% | 40% |
| Standard | ISO 22241 | ISO 18611 |
| Used in | Road vehicles, off-road plant and machinery | Marine SCR systems that specify it |
| Crystallises at about | −11 °C | 0 °C |
AUS 40 needs the same care as AdBlue®, with one extra point: it crystallises at a much higher temperature.
AUS 40 starts to crystallise at about 0 °C. In most Australian ports that is rarely an issue, but storage tanks and lines in exposed or southern locations can get close in winter. Crystals can block lines and filters. Keep tanks and lines above that temperature where needed, and let any crystals fully redissolve before use.
Like all urea solutions, AUS 40 breaks down faster when stored hot, releasing ammonia and losing concentration. Shade dockside tanks where you can and use stock in rotation rather than holding it for long periods.
Store and transfer it in polyethylene, polypropylene or stainless steel. Urea solutions attack copper, brass, zinc, aluminium and mild steel, which also contaminates the fluid. See our guide to compatible materials.
Use dedicated transfer hoses and fittings, keep fill points capped, and never let seawater, diesel or oil into the tank. Label AUS 40 tanks and fill points clearly so they cannot be confused with AdBlue® or fresh water.
Dockside and port deliveries take more planning than a depot drop. Having these details ready lets us quote accurately and schedule the tanker.
A Certificate of Analysis is available on request for each batch, and the full specification is on the spec sheet above.
Only if the engine or SCR maker specifies AUS 32. In a system set up for AUS 40, AdBlue carries less urea per litre, so NOx reduction may fall short and consumption rises. Check the maker's documentation.
No. Road and off-road SCR systems are designed for AdBlue at 32.5 percent urea. AUS 40 can trigger quality-sensor faults, derate mode and exhaust deposits.
AUS 40 starts to crystallise at about 0 degrees, much higher than AdBlue at about minus 11 degrees. Keep tanks and lines above that temperature in cold locations.
AUS 40 is covered by ISO 18611. AdBlue, or AUS 32, is covered by ISO 22241. Ask us for the spec sheet and a batch Certificate of Analysis.
Polyethylene, polypropylene and stainless steel. Avoid copper, brass, zinc, aluminium and mild steel, which urea solutions attack.
Tell us your volumes and we'll sort supply and delivery.