Overview
ISO 18611-3:2014 - Ships and marine technology - Marine NOx reduction agent AUS 40 - Part 3: Handling, transportation and storage - provides best-practice recommendations and requirements for preserving the quality of AUS 40 (aqueous urea solution) throughout the distribution chain. The standard ensures AUS 40 remains compliant with the quality requirements in ISO 18611‑1, so selective catalytic reduction (SCR) systems on ships and marine engines function reliably.
Key topics and technical requirements
- Scope and purpose: Guidance for handling, transportation, storage, sampling and quality assurance of AUS 40 for marine applications, irrespective of manufacturing method.
- Materials compatibility: All materials in direct contact with AUS 40 must be compatible. Examples of recommended materials include:
- Highly alloyed austenitic Cr‑Ni and Cr‑Ni‑Mo stainless steels (e.g., 304/316 grades)
- Titanium and nickel‑based alloys (e.g., Hastelloy)
- Polymers free of additives: polyethylene, polypropylene, PTFE, PFA, PVDF copolymers
- Fibreglass with appropriate resin
Not recommended: carbon steels (and zinc‑coated steels), copper and copper alloys, aluminium, magnesium, nickel‑coated coatings, and certain solders - materials that react with ammonia or leach contaminants.
- Temperature and storage: Recommendations to avoid prolonged storage above 25 °C (to prevent urea decomposition and water evaporation) and avoid storage below 1 °C (to prevent solidification). Protect from sunlight and consider insulation/heating where necessary.
- Shelf life (guidance):
- 0–25 °C: minimum 18 months
- <30 °C: 12 months
- <35 °C: 6 months
-
35 °C: possible significant loss - check every batch
- Exposure above 40 °C greatly accelerates degradation.
- Cleanliness and contamination control: Surfaces must be free of fuel, oil, detergents, dust. Final cleaning ideally with distilled/de‑ionized water and an AUS 40 rinse; avoid tap water as final rinse unless followed by AUS 40.
- Quality assurance: Sampling, verification, release procedures, and handling of non‑conforming product are covered. Dedicated and non‑dedicated bulk operations have separate recommendations.
Applications and users
Who uses ISO 18611‑3:2014:
- Ship owners, fleet operators and ship managers ensuring on‑board AUS 40 quality
- OEMs and engine manufacturers specifying SCR system requirements
- AUS 40 producers, distributors, and logistics providers (tankers, IBCs, drums)
- Tank and container manufacturers, tank cleaning and sampling services
- Catalyst suppliers and converter system integrators
Practical benefits: reduces SCR system failure risk, preserves catalyst life, simplifies procurement and logistics by defining handling and storage best practices.
Related standards
Keywords: ISO 18611-3:2014, AUS 40, marine NOx reduction agent, handling transportation storage, SCR, urea solution, shelf life, materials compatibility, ships, marine technology.