Product data
PROTICKS AUS40 is a 40% aqueous urea solution for marine SCR systems, manufactured under ISO 18611 certification and meeting the requirements of IS 17661 (Part 1):2022. The values below are the product specification.
| Parameter | Specification |
|---|---|
| Appearance | Clear, colourless liquid |
| Urea concentration | 40.0 ± 0.5 % by mass |
| Density @ 20 °C | 1.105 - 1.117 g/cm³ |
| Refractive index @ 20 °C | 1.393 - 1.397 |
| pH @ 20 °C | 9.0 - 11.0 |
| Crystallisation onset | Near 0 °C; see batch documentation |
| Biuret content | ≤ 0.3 % |
| Aldehydes | ≤ 5 mg/kg |
| Insoluble matter | ≤ 20 mg/kg |
| Phosphate (as PO₄) | ≤ 0.5 mg/kg |
| Calcium + magnesium | ≤ 0.5 mg/kg |
| Copper + zinc | ≤ 0.2 mg/kg |
| Storage temperature | +5 °C to +30 °C |
| Shelf life | 12 - 18 months sealed, typical |
These are specification values, not a certificate. The Certificate of Analysis issued with your batch reports its measured results and is the document to check before approving supply.
What the impurity limits are for
The impurity parameters matter more than the headline concentration. An SCR catalyst is poisoned by metals and fouled by insolubles, and the damage is cumulative and expensive.
- Biuret forms when urea is overheated and can deposit in the dosing system. PROTICKS AUS40 is specified at ≤ 0.3%, tighter than the 0.8% limit in ISO 18611-1.
- Calcium, magnesium, copper and zinc are catalyst poisons. Limits are in milligrams per kilogram because that is the order at which they cause harm.
- Insoluble matter blocks filters, dosing nozzles and fine strainers.
- Aldehydes and phosphate indicate contamination in the urea feedstock or the water used.
- Refractive index and density give a fast concentration check, but they confirm concentration only; they say nothing about the impurities above.
Storage and crystallisation
AUS40 crystallises at a much higher temperature than AUS32. The urea and water eutectic sits near 32.5% by mass, which is why AUS32 stays liquid down to about −11 °C. AUS40 is above that composition, so urea begins to come out of solution close to 0 °C. Keep it above +5 °C.
The figure for a given batch belongs to that batch, so take crystallisation onset, storage range and shelf life from the current product data sheet and the Certificate of Analysis rather than from a general table. Crystallisation does not spoil the product. Redissolve it uniformly and slowly, because a partial thaw leaves concentration uneven through the tank, and never add water to correct it. Full storage and handling guidance.
AUS40 against AUS32
| AUS32 (AdBlue) | AUS40 (marine) | |
|---|---|---|
| Urea by mass | 32.5% | 40% |
| Standard | ISO 22241 | ISO 18611 · IS 17661 |
| Designed for | Road vehicle SCR | Marine SCR installations |
| In a marine system | Under-doses a system mapped for 40% | Correct dosing for the approved installation |
Use the concentration your engine or SCR manufacturer specifies. Full comparison.
SCR performance is a system property
Reduction efficiency is a property of the complete engine and SCR installation (catalyst condition, exhaust temperature, dosing control and operating profile), not of the reagent. Correct reagent is necessary for the system to perform as approved; it does not by itself determine the result, and we cannot quote a conversion figure for your vessel.
Documents
Request a sample Certificate of Analysis, the current product data sheet and the MSDS with the quotation. The Certificate of Analysis for your batch is issued with the delivery.
Common questions
What is the urea concentration of AUS40?
40.0% by mass, with a specification tolerance of ± 0.5%. That is the concentration marine SCR systems specified for AUS40 are mapped to. AUS32 at 32.5% is a different product.
At what temperature does AUS40 crystallise?
Close to 0 °C, not −11 °C. −11 °C is the AUS32 figure and does not apply to a 40% solution, because 40% urea sits above the urea and water eutectic. Take the figure for your batch from the product data sheet, keep the product above +5 °C, redissolve any crystals uniformly, and never add water to correct crystallisation.
What is the shelf life of AUS40?
Typically 12 to 18 months sealed, when stored between +5 °C and +30 °C and out of direct sunlight. That is a typical range, not a batch guarantee. Confirm the figure for your batch against its documentation. Storage history affects it, so record receipt dates and rotate stock.
Is a density check enough to verify a delivery?
No. Density and refractive index confirm concentration only. They tell you nothing about biuret, insolubles or metal contamination, which is what the Certificate of Analysis reports.
Why is the biuret limit tighter than the ISO limit?
ISO 18611-1 sets the biuret limit at 0.8%. PROTICKS AUS40 is specified at ≤ 0.3% because biuret can deposit in dosing equipment, and a tighter limit reduces that risk over the life of the system.