AdBlue Storage Requirements: Temperature, Materials and Shelf Life

AdBlue is simple stuff, but it is fussy about how it is kept. Store it badly and it degrades or becomes contaminated, and contaminated AdBlue can damage the SCR system it is meant to protect. This guide covers what AdBlue needs from a storage tank, whether you buy it in drums, IBCs or by the bulk load.

What AdBlue is

AdBlue is a 32.5% solution of high-purity urea in deionised water, made to the ISO 22241 standard. Diesel engines with selective catalytic reduction (SCR) inject it into the exhaust, where it breaks down harmful nitrogen oxides. Because the SCR system is sensitive, the fluid has to stay within spec all the way from the delivery to the vehicle.

Temperature

Temperature is the biggest factor in how long AdBlue lasts.

• Heat: AdBlue slowly breaks down over time, and heat speeds that up. Shelf life is commonly quoted at around 12 months when it is kept below about 25°C, and it falls noticeably in sustained heat above 30°C. In much of Australia that makes shade and insulation more important than frost protection.
• Sunlight: Keep tanks and containers out of direct sun. UV and solar heat both shorten its life.
• Cold: AdBlue freezes at about -11°C and expands as it does. Freezing does not ruin it, and it can be used once thawed, but the tank and lines need to cope with the expansion. Sites in alpine areas or inland winters should allow for this.

For larger installations, temperature control and insulated tanks keep AdBlue in its comfortable range year round.

Contamination

ISO 22241 sets tight limits on impurities, and it does not take much to exceed them. Common causes are:

• dust and dirt getting into open containers or vents
• tap water used for rinsing or topping up
• residue from diesel, oil or coolant in shared equipment
• the wrong tank or hose materials leaching metals into the fluid

The fixes are straightforward: keep it in a closed system, use filtered vents, and keep all AdBlue equipment dedicated to AdBlue. Never reuse fuel drums, jerry cans or funnels.

Materials that are compatible, and ones that are not

AdBlue is corrosive to some common metals, so tank and fitting materials matter.

• Suitable: stainless steel (316 is the usual choice for bulk tanks), and approved plastics such as HDPE and polypropylene.
• Avoid: copper, brass, zinc and galvanised steel, aluminium, and plain carbon steel. These corrode and contaminate the fluid.

This catches people out when they adapt a spare fuel tank or use brass fittings from the parts bin. It is cheaper to buy the right equipment than to replace an SCR system.

Ventilation and safety

AdBlue is generally not classed as a dangerous good, and it is not flammable. When it gets warm in an enclosed space, though, it can give off ammonia vapour, so store it somewhere with reasonable ventilation. Spills dry to white urea crystals, which should be cleaned up with water rather than left to spread. Check the supplier's safety data sheet for handling details.

Drums, IBCs or a bulk tank?

• Drums and IBCs suit low usage, but every changeover is a chance for contamination, and partly used containers sit around for a long time.
• A bulk AdBlue tank suits fleets, depots and mine sites using AdBlue every day. Deliveries go straight into a sealed system, dispensing is metered, and stock turns over faster, so the fluid is fresher when it reaches the vehicle.

Our AdBlue storage tanks run from 1,000L to 50,000L+, in 316 stainless and approved polymers, with temperature control and purity monitoring available. If you also store diesel, our diesel and AdBlue dual solutions keep both on one pad with separate dispensing.

Need a hand with AdBlue storage?

Tell us how much AdBlue you use and where the tank will sit, and we will recommend a setup. Contact us or call 1300 210 480.