Fabric and Fiber Insulation Information

Selecting fabric and fiber insulationFabric and fiber insulations are textile materials which reduce the rate of thermal transfer between two temperatures, typically to moderate temperature fluctuations of a structure's interior.




To maintain the comfort of building occupants, it is necessary to isolate the structure's interior from ambient outdoor temperatures, which vary greatly depending upon season and local climate. Completing a building envelope to prevent the free exchange of air and the entry of precipitation, while still permitting interior ventilation, is the first step in regulating interior temperatures.


The variety of materials used in structure construction means that thermal conduction and convection is inevitable for every building; radiance is another common cause of heat transfer. Insulation is rarely enough on its own to keep indoor temperatures comfortable, and considerable energy is expended to warm or cool building interiors. To limit conduction, convection, and radiance, contractors frequently utilize fiber and fabric insulations to help retain temperature-conditioned air. Insulation is often viewed as a sustainable initiative, as preventing heat loss or gain can often pay for the insulation many times over due to energy savings.


Fabric and fiber insulations are a popular means of limiting conduction and convection, and if the insulation is exposed to sunlight, a metalized film or other reflective surface can reduce radiance. Fabrics and fibers trap air within the insulation, which is the primary mechanism of preventing the conductive and convective transfer of heat.


Fabric and fibers are favorable since they are readily available; often made from sustainable resources; are relatively inexpensive; can be shaped or formed into virtually any dimension or pattern; are easily installed; and can be treated or modified to enhance other desirable characteristics, such as fire resistance and noise dampening.


Visit the industrial fabrics and fibers selection guide for more general information about fabrics and fibers.




Fiber insulation materials selection 




Insulative materials are produced in a wide variety of form factors to increase versatility between applications. Fibers can be woven into structures to produce a cohesive article, or can be left unwoven to permit random fiber distribution and orientation.


  • Blanket/batting: sheets of woven material which can be used to contain unwoven and loose-fill insulating materials between layers. This is the most common form for fabric insulators.
  • Cordage/rope: fibers are twisted or braided to create a thin but long material, which can seal around doors or other openings. 
  • Fiber/monofilament: a single fiber of insulative material, which is often the medium of loose-fill, blown-in, and sprayable insulation processes.
  • Roving/yarn: roving constitutes bundles of slightly twisted, drawn out fibers. Yarn is a continuous length of plied fibers.   
  • Sleeve/wrapping: these are can insulate pipes, tubes, ducts, hoses, or other similar building infrastructures.
  • Strand/multi-filament: multiple fibers are effective for composite reinforcement applications.

  • Webbing/stripping: insulation available as ribbon, webbing, or tape.



Insulation value formula equationThermal Conductivity (K-value)


The measurement of energy, in BTU's per hour, that will be transmitted through a piece of material measuring 1' x 1' x 1", which will raise the temperature on the other side of the material by one degree Fahrenheit.


Thermal Conductance (C-value)


A similar definition to K-value, except this value takes into account the material thickness as well


Thermal Resistance (R-value)


The ratio of the temperature difference across the insulator and the heat transfer per unit area per unit time.


Thermal Transmittance (U-value)


The value applied to the thermal transmittance of an entire system, including drywall, framing, fabric insulation, siding, and any other structure components.


Thermal Characteristics


Measured and non-measured responses of insulation in the presence of heat, such as dimensional changes, temperature ratings, thermosetting qualities, decaying and degrading, and others.




The length, width, and thickness of an insulative fabric. Some insulations can be cut by hand tools on-site, but others may require specialized instruments.




  • Acoustically insulative: fabric reduces the transmittance of sound waves between walls.
  • Chemically resistant/inert: materials resist damage from acids, bases, oils, or other common chemicals, or are chemically inert to most contaminants.
  • Electrically conductive: fabrics have a low resistivity, which aids in electronic, anti-static, or electrostatic discharge applications.
  • Electrically insulative: fabrics have a high resistivity, which isolates electrical components.
  • Flame resistant/retardant: fabrics resist ignition or delay combustion. These products may be rated by a standards body.
  • Hydrophillic: the fabric absorbs water without compromising thermal integrity.
  • Hydrophobic: the fabric is waterproof or has a waterproof membrane.
  • UL approved: the insulation has met recommended insulative conditions, specifications, or features.

  • Weather resistant: the material does not degrade when exposed to fluctuating temperatures, wind, snow, humidity, or other mild-to-moderate weather conditions.



Many industrial standards outline best practices to maximize fiber insulation efficiency. Amongst them include:


- ASTM C1014 Spray-applied mineral fiber insulation specifications

- ASTM C1015 Installing cellulose and mineral fiber loose fill

- ASTM C1086 Glass fiber insulation specifications

- ASTM C1320 Installing mineral fiber insulation

- ASTM C545 Mineral fiber pipe insulation

- SAE AMS 3679 Ceramic fiber insulation




National Insulation Association—Techs & Specs: K-Value, U-Value, R-Value, C-Value 


U.S. Department of Energy—Insulation 


Thermaxx Jackets—The R-Value, K-Value, and C-Value of Insulation 


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