Arla 32: what it is, what it is for and how to use it

Arla 32 is a solution used in diesel-engine vehicles that have a Selective Catalytic Reduction (SCR) system.

Since 2012, due to the emission limits set by Conama Resolution No. 403/2008 (Conama is Brazil's National Environment Council), heavy vehicles produced in Brazil have been equipped with SCR, and the use of the liquid nitrogen oxide (NOx) reducing agent is mandatory.

To learn more about the product, see:

• What it is;
• What it is for and why it matters;
• Where to buy it;
• How to use it;
• Frequently asked questions.

What is Arla 32?

“Arla” is the Brazilian acronym for Agente Redutor Líquido Automotivo (automotive liquid reducing agent). The number 32 refers to the required urea concentration, which is 32.5%.

What does all this mean?

First, that the product is a solution of urea in demineralized water. Urea makes up 32.5% of the compound, while the other 67.5% is the water used in the formulation.

It is important to stress that it is not a fuel type or a lubricant, but a pollutant-reducing solution. That is why it does not replace diesel, oil, engine additives or any other truck fluid.

What is Arla 32 for and why does it matter?

It is responsible for controlling the emission of nitrogen oxides (NOx) in the exhaust gas of diesel vehicles with an SCR system, turning these compounds, which are harmful to the atmosphere, into nitrogen and water — harmless substances.

This reduction in the emission of pollutants from fuel combustion is up to 98%. In other words, it is an important measure to reduce the environmental impact of operating trucks and buses equipped with the system.

In addition to contributing to sustainability, the correct use of Arla 32 helps keep the SCR system working as intended: controlling NOx in the exhaust. For this, the product must be original, used in the correct reservoir and kept free of any mixture with diesel, water or other components.

But is it actually mandatory?

Yes. Since 2012, due to the stricter emission limits set by Conama Resolution No. 403/2008, heavy vehicles produced in Brazil have been equipped with SCR, and the use of the liquid NOx reducing agent is mandatory.

Installing any device intended to bypass the control system in order to do without the product is classified as an environmental offense by IBAMA, Brazil's federal environmental agency.

In fact, the fines range from R$ 500.00 to R$ 10,000.00, depending on the severity of the situation.

Where to buy Arla 32?

The compound can be purchased at fuel stations, from distributors or online.

You should pay attention to the label and buy a product that has the INMETRO seal (INMETRO is Brazil's National Institute of Metrology) and complies with ISO 22241-1.

After all, an incorrect composition, the presence of impurities or incorrect dosing of its components can form deposits in the vehicle's injectors and catalytic converters, preventing the SCR system from working and causing serious, irreversible problems to the vehicle.

It is also worth checking the product's manufacturing date, because its shelf life depends on storage conditions. This check keeps the label guidance together with the care already needed to buy Arla 32 that meets the indicated standard.

How to use Arla 32?

The product has a specific container, usually a tank with a blue cap, near the fuel tank.

Care is needed, because the liquid must not be mixed with other components, such as diesel oil, water, additives or loose urea. Only original products, within the correct specification, should be used.

It should be included in the trucks' checklist so that the need for replacement or change is observed during preventive maintenance.

To avoid any doubts when adding Arla 32 to the truck or bus, it is fundamental that the people responsible are qualified and trained. The routine should reinforce which reservoir is correct, that the tank is exclusive to the product and that no mixing should be done while refilling it.

Frequently asked questions

How should Arla 32 be stored?

Before use, the liquid should be stored in a dry place, free of humidity and protected from rain and sunlight. Ideally, it should be kept at room temperature.

What is the shelf life of Arla 32?

It has a shelf life of one year when stored at temperatures of up to 30 ºC and six months when kept at temperatures between 30 ºC and 35 ºC. It is always important to check the product's manufacturing date.

Can I add water to the same reservoir as Arla 32?

Never. Do not add absolutely anything to the reservoir exclusive to Arla 32.

As we have already mentioned, any alteration leads to fines and can cause damage to the vehicle.

Can I buy urea, mix it with water and put it in the Arla 32 tank?

No. The urea added to the original composition has a unique purity. That is why the product is manufactured only in a specialized laboratory.

Does Arla 32 pose risks to human health?

No. Arla 32 is not toxic, explosive or flammable. The solution of urea in demineralized water is used to control nitrogen oxides in the exhaust of diesel vehicles with an SCR system.

In addition to these questions, IBAMA provides a guidance page about Arla 32 (in Portuguese) that you can check.

And remember:

Servicing the vehicle and refilling it with Arla 32 should be part of your maintenance management.

Want to know what else to include in your fleet's preventive maintenance routine? See our complete post on the subject.