Thermal insulation plays an important role in ensuring that mechanical systems operate efficiently and effectively. A wide range of commercial and industrial industries use insulation to reduce energy usage, control process temperatures, and more. 

However, not all insulation materials are created equal. Some materials are better suited for high or low-temperature applications, while others have properties that allow them to withstand high compressive forces or resist vapor drive. Before choosing insulation products for your next project, be sure to explore which materials are right for your specific application needs.  

Goals of Thermal Insulations

Some common goals of thermal insulation include:

• Minimizing energy consumption and costs: Thermal insulation reduces energy loss by limiting heat transfer between hot and cold materials.
• Maintaining desired temperatures: Thermal insulation reduces unnecessary fluctuations in temperature, boosting energy efficiency and helping you maintain desired ambient and touch temperatures. This could be in the form of a process pipe or a conditioned space. 
• Personnel protection: Thermal insulation helps improve worker safety by protecting them from extremely hot or cold equipment by bringing surface temperatures closer to ambient conditions.
   

Properties of Insulation

Learn more about the properties of insulating materials below:

Thermal Conductivity

Thermal conductivity, commonly referred to in the insulation industry as K-value, is characterized as the rate at which heat can flow through a material and is measured in Btu-inch/hour per square foot per degree F. A material with a lower K-value will better resist the flow of heat through it, making it an effective insulator. A thermal insulation material typically has a K-value of less than 0.5 Btu-in./(hr-ft²-°F). K-value is independent of a material's thickness. By considering the amount of insulation being used with a given thermal conductivity, one can determine the overall effectiveness of a given insulation system.

Thermal Resistance

Thermal resistance, also known as R-value, is one of the common labels one may find on an insulation’s packaging. It is a numerical indicator of the effectiveness of the total amount (or thickness) of a given insulation used. R-value is measured in (hr-ft²-°F)/Btu. It can easily be calculated by dividing an insulation material's thickness by its K-value. 

Thermal Conductance

Thermal conductance is typically referred to as a C-value and is the reciprocal of thermal resistance.  It represents the time rate of heat flow through a unit area of a material's thickness. A lower C-value means an insulation system will be more effective in inhibiting heat transfer. The C-value can be calculated by dividing the K-value by the material thickness. 

Emissivity

Emissivity refers to a material’s ability to absorb and emit heat to its surroundings in the form of radiation. It is expressed as a unitless ratio between 0 and 1 using the symbol ε. A material with ε=0.9 will exchange a large amount of heat with its surroundings via radiation, while a material with ε=0.1 will reflect most of this radiation and exchange less heat in this manner.

Emissivity is most important to consider on the outermost surface of an insulation system, which is why it is commonly referenced when discussing jacketings for insulation systems. A high emissivity material, such as ASJ or PVC, can help bring an insulation’s surface temperature closer to its surroundings. This can help reduce the surface temperatures of hot systems for personnel protection purposes or raise the surface temperature of cold systems to help mitigate the risk of surface condensation.

Types of Thermal Insulation

Thermal insulation exists in various forms, each with unique properties and strengths. Common categories of insulations commercially available include:

• Fibrous: An insulation material that relies on inorganic fibers to trap pockets of air within the thickness of the material.
• Cellular: An insulation material that utilizes a solid medium to form a structure of cell walls that creates sealed cells of gas throughout the thickness of the material.
• Granular: An insulation material that consists of small nodules containing voids or hollow spaces within the solid structure of the insulation.

Considerations for Choosing Thermal Insulation

When choosing thermal insulation for a project, consider the following elements. This information is typically found on a material’s technical data sheet.

• Operating temperature: What temperature is the application to be insulated? Thermal insulation's temperature range can span from cryogenic to extremely hot. An insulation material should be rated to function within the desired process range.
• Vapor drive: Will the insulation be subject to a high vapor drive, such as in below-ambient processes? If so, ensure the insulation material (or jacketing) has a low permeability to resist moisture ingress.
• Exposure to flame: Will this insulation be used in a location where exposure to fire is a potential concern? If so, a noncombustible insulation material should be considered.
• Compressive forces: Will this insulation need to withstand significant compressive loads while in service? If so, select an insulation with a suitably high compressive strength.

Understanding the specific requirements and conditions you are working with is essential for maintaining performance and safety.

Cellular Glass

Cellular glass insulation is one example of an insulation material capable of spanning both hot and cold applications. It’s a rigid material, consisting of millions of completely sealed glass cells. Its service temperature range of -450 °F to 900 °F makes it well-suited for a wide variety of applications.

Cellular glass boasts a water vapor permeability rating of zero, meaning it will not allow moisture to pass through it and condense onto cold surfaces. When paired with a compatible joint sealant, it is possible to achieve a completely sealed insulation system in order to defend against moisture intrusion in critical low-temperature processes.

Cellular glass is also capable of performing at hot temperatures. It is versatile for projects with both cold and hot requirements or requiring wide temperature cycling processes.

Being inorganic, cellular glass is also noncombustible, and will not give off dangerous gases in the event of a fire. It is suitable for processes that carry flammable fluids, as it will not pose a risk of absorbing hazardous materials to potentially act as a fuel source down the road.

Cellular glass is manufactured in block form and can be easily cut to various shapes and sizes that may be needed for a particular job.

Find FOAMGLAS^® for Hot and Cold Applications From Specialty Products and Insulation

When you need insulation products for hot and cold applications, turn to the wide selection from Specialty Products and Insulation.

At SPI, we have over forty years of experience and offer a wide range of durable, high-quality products designed to help you boost energy savings and your return on investment. We also offer custom fabrication services, and our team will assist you with finding the right materials for your unique applications. 

Are you ready to get started? Browse FOAMGLAS^® products available from Specialty Products and Insulation, or contact us to learn more today.