Types of Thermal Insulation Used in Tanks (FP, for UAN, for Water)

Choosing the right storage tank is a key decision. While the construction material (such as steel tanks or acid-resistant tanks) and capacity are obvious parameters, the temperature of the stored medium is equally important. This is why insulated tanks constitute a separate, crucial product category, and the type of insulator used directly affects safety, operational costs, and process stability. Investing in used tanks with factory, refurbished insulation is often the most economical solution. In this article, we will look at the most popular types of thermal insulation, indicating which one is best suited for specific applications, such as fire suppression tanks, water tanks, or fertilizer storage.

We invite you to contact us. Our specialists will help you select the right used tank – steel, acid-resistant, or insulated – perfectly matched to your technological and budgetary needs.

Why is Insulation Crucial?

The application of an insulation layer has three main purposes:

1. Protection against freezing: A critical function for FP tanks (fire suppression tanks) and tanks for technological water or rainwater, located outdoors in our climate zone.
2. Protection against crystallization: Essential, for example, for UAN tanks (Urea Ammonium Nitrate solution), which loses its properties at low temperatures.
3. Maintaining heat (or cold): In many industrial processes, steel tanks or acid-resistant tanks serve as buffers for hot water, glycol, oils, or media that must maintain a constant temperature so as not to lose their parameters.

Overview of Insulation Materials in Tanks

Several main insulation technologies dominate the market. Each has different properties and performs best under different conditions.

1. Mineral Wool (Rock or Glass Wool)

This is one of the most proven and frequently used materials in the industry, especially where safety is a priority. Wool insulation comes in the form of mats or rigid boards, which are wrapped around the steel tank, and then the whole assembly is protected by an external metal jacket (e.g., aluminum or galvanized steel).

Advantages:

• Non-flammability: Mineral wool is classified as non-combustible material (Class A1). This makes it the absolute best choice for fire suppression tanks and installations with an increased fire risk.
• High thermal resistance: It perfectly withstands very high temperatures, making it ideal for insulating buffer tanks with hot water, glycol, steam, or oils.
• Durability: It is resistant to aging processes, rodents, and chemicals.

Disadvantages:

• Water absorption: Requires an absolutely tight external jacket. Wet wool loses its insulating properties and can accelerate corrosion under insulation (CUI).
• Greater thickness: To achieve the same insulation coefficient as foam, the layer of wool usually needs to be thicker.

2. Polyurethane (PUR) or Polyisocyanurate (PIR) Foam

Rigid PUR/PIR foams are a modern solution with excellent thermal insulation properties. They can be applied by spraying directly onto the tank or in the form of ready-made panels (so-called 'sandwich' panels).

Advantages:

• Best insulation (low lambda): PUR foam offers the best insulation with the smallest layer thickness. This is crucial when every centimeter counts.
• Low water absorption: The closed-cell structure makes the foam almost completely resistant to water and moisture.
• Tightness: In the case of spray application, it creates a uniform, bridge-free layer that adheres perfectly to the tank.

Disadvantages:

• Fire resistance: Although PIR foams have increased resistance (they are self-extinguishing), they are not a non-combustible material to the same extent as mineral wool.
• Lower resistance to high temperatures: They are usually not used for media with temperatures exceeding 80-100°C.

Main application: Ideal for UAN tanks (where cold protection efficiency is important) and tanks for water and rainwater.

3. Synthetic Rubber (e.g., Armaflex)

This is a flexible insulation primarily used in refrigeration and air conditioning, but also for smaller process tanks (e.g., in acid-resistant steel tanks in the food industry).

Advantages:

• Condensation protection: It has a very high diffusion resistance factor, which prevents water vapor from condensing on cold surfaces (e.g., tanks with chilled water or glycol).
• Flexibility: Easily adapts to complex shapes, valves, and fittings.

Disadvantages:

• Price: This is usually the most expensive solution listed.
• Limited mechanical resistance: Requires protection against damage.

Summary

The choice of insulation depends on priorities:

• If you store hot media or non-flammability is a priority (e.g., FP tanks) – choose mineral wool.
• If you store media sensitive to frost (e.g., UAN, water) and insulation efficiency is important – choose PUR/PIR foam.
• If you are battling condensation on a cold tank – consider synthetic rubber.