One of the most frequently asked questions Armacell receives is, “How many kinds of insulating material types are out there?” In this blog, we will explore the three most common materials used to make insulation and their structures. Our latest Armacell Answers video also provides an excellent overview of this topic for additional learning. 

It is known commonly that all insulation materials and structures are composed of small gas pockets that slow the movement of heat through the material. The slower the heat moves through one gas pocket to the next, the better the insulative property of the material. The three most used and common insulation materials available today are Cellular, Granular and Fibrous.

Cellular insulations, as the name suggests, are made up of cells of gas within a material that are either completely sealed off from each other or are open to gas exchange. A material is considered open cell if less than 90% of the cells are sealed off from each other. With gas free to be exchanged between cells and the surrounding air, these materials tend to have high water absorption and permeability. One example of this part of the family is flexible urethane foam. Now, if 90% of the cells or more are completely sealed off from each other, with no gas exchange between them, the material is considered closed cell. This lack of gas exchange leads to a low water absorption and low water vapor permeability. Flexible elastomeric foam or FEF falls into this family while rigid versions include cellular glass, phenolic foam, poly-iso, and polyethylene. 

Granular insulations are composed of small nodules that contain voids or hollow spaces. Gases can be transferred between the spaces, meaning granular materials generally have high water absorption and permeability. Granular materials can be further broken down into flexible types, such as aerogels and certain microporous, that can be bent without a loss in strength or integrity. The second granular material type are rigid materials, such as calcium silicate, perlite, and other types of microporous, which oppose any tendency to bend.

Fibrous insulations are composed of small-diameter fibers that finely divide the air space and include varying levels of binders, depending on the application. Fibrous insulations tend to have high water absorption and high-water vapor permeability; therefore, a vapor retarder jacket or coating is needed to avoid moisture ingress. Examples of fibrous insulations include fiberglass and stone wool. 

Armacell’s Portfolio Offerings 

Armacell is the pioneer in flexible elastomeric foam technology with our ArmaFlex® insulation solution celebrating its 70 year anniversary in 2024! With its closed cell structure, our elastomeric foam solutions have low water vapor absorption and permeability, superior corrosion under insulation mitigation properties, and high thermal resistance values.  Armacell also offers a family of polyethylene products, another closed cell material, used to prevent condensation and heat loss, and protect pipes from freezing

Lastly, the ArmaGel® family of next generation aerogel products are extremely flexible and bendable, offering fantastic thermal performance and mitigation of corrosion under insulation.