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This page illustrates and describes perlite insulation materials. We've added these examples because of frequent questions about the visual identification of various insulating materials, about the properties of various insulating substances, and because of the need to recognize asbestos and non-asbestos-containing materials. This website assists building buyers, owners or inspectors who need to identify non-asbestos-containing insulation materials as well as asbestos-containing materials (or probable-asbestos) in buildings by simple visual inspection. Perlite photographs in this article are courtesy of Redco and their website about perlite insulation.

See INSULATION INSPECTION & IMPROVEMENT and IDENTIFICATION of ASBESTOS in BUILDINGS for details about foam and other building insulation types; see FIBERGLASS HAZARDS for a discussion of mold problems in fiberglass insulation. © Copyright 2010 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

Perlite Building Insulation

Perlite building Insulation is a non-asbestos-containing material which has an R-value of about 2.7 per inch and would not be expected to contain asbestos.

Perlite is a type of rock (a form of volcanic glass) which is mined, crushed, heated and thus expanded (4 to 20 x original volume) to form an inorganic insulating material. (Also see Vermiculite Insulation.)

Water trapped in the rock causes it to expand. Perlite insulating material is produced in granular forms from coarse to a fine powder which weighs about two pounds per cubic foot. Photo courtesy of Redco .

Perlite is used for the insulation of low-temperature application equipment such as cryogenic (-100 degC or -150 degF) and super-cold storage tanks and test chambers. Perlite insulation is also used in food processing applications (up to 4 degC or 40 degF - about the minimum food refrigeration temperature).

Perlite building insulation is produced in a granular or even a powder form, but by some manufacturers it is formed into an insulating board (by combining perlite with gypsum, for example for use under building roofs).

Perlite insulation materials are resistant to mold, rot, and rodents. Perlite also resists moisture uptake, making it useful for use in areas exposed to water or dampness such as in floor leveling compounds and under-floor insulation where it may also be used for noise control (as a sound-deadening material, possibly between building floors). Perlite as an under-floor insulation and as an acoustical insulator is described by the Schundler Company.

Perlite insulation density and weight

Perlite insulating products are produced in a range of densities (weight per cubic foot) from two pounds per cubic foot to fifteen pounds per foot.

Perlite has a typical density of 3-4 pounds per cubic foot in building insulation products, and is described by various industry sources as inexpensive and dimensionally stable (doesn't shrink) and non-combustible.

Perlite as a green building material

Some writers name perlite insulation products as a "green building material", probably because it is a natural, mined resource (not considering the energy costs of mining and production), and more, because perlite is used as a concrete additive to make insulating and light-weight concrete, or as an insulating material to fill the cores of masonry block constructed walls. Perlite insulation may also be used to insulate masonry wall cavities (between brick courses in a structural brick wall) or in a building interior to fill the cavity between a masonry exterior wall and the interior finish-wall furring strips and drywall.

More information about perlite insulation is available from Redco II, a perlite insulation manufacturer in North Hollywood, an industry source for this insulating material. Redco II sells perlite for horticultural purposes (those white particles you see in some brands of potting soil), for industrial and construction applications such as an additive in the formation of concrete, and for general industrial uses including as a filtering medium.

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Technical Reviewers & References

• InspectAPedia.com^® - Daniel Friedman
• Critique, contributions wanted: Contact Us to suggest corrections or additions to articles at this website, and if you wish, to receive online listing and credit as a contributor. Particular thanks are due to the many experts and also consumers who read and critique technical articles at InspectAPedia.com.
• Additional technical contributors & reference sources for this article are listed below.

Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.
 
How to Identify Building Insulation Materials
  Asbestos Pipe Insulation
Mold Growth Resistance of Foam Insulation
Asbestos-Free Insulation Materials
  Cotton Insulating Batts
  Cellulose loose fill insulation
  Concrete insulation, light-weight
  Fiberglass Insulation
  Foam Board Insulation
  Foam Insulation Types - Visual Id
  Homasote & Other Insulating Board
  Icynene Foam Spray Insulation
  Insects & Foam Insulation
  Mineral Wool - Rock Wool Insulation
  Mold in Fiberglass Insulation
  Mold in Foam Insulation
  Paper Duct Insulation
  Perlite Insulation
  Perlite Insulation
  POLYISOCYANURATE FOAM INSULATION
  POLYSTYRENE FOAM INSULATION
  SUPER HI-R INSULATION
  RADIANT BARRIERS
  RIGID FOAM USE INDOORS
  Urea Formaldehyde Foam Insulation UFFI
  Vermiculite Insulation (from some mines vermiculite may contain asbestos)

• Perlite Institute is an industry association formed in 1949 to promote the use of perlite insulation materials and to conduct research about perlite. The Perlite institute offers a 2002 article confirming that Perlite does not contain asbestos. A separate study supported by the Perlite institute (also published in 2002) concludes that perlite is a safe product, citing studies establishing that it is not a significant respiratory hazard to workers (Cooper 1975-76, Weill, Tulane Univ., 1994, and other studies). The institute also cites that for some workers exposure to perlite (presumably perlite dust) can result in temporary physical irritation, discomfort, impaired visibility, and enhancement of accident potential.
• Redco II, North Hollywood CA 818-759-2255 maintains Perlite.Net an information website about perlite insulation.
• Schundler Company, Edison, NJ 732-287-2244 provides information about the application-use of both perlite and vermiculite insulation products.
• Asbestos: How to find and recognize asbestos in Buildings - visual inspection methods, list of common asbestos-containing materials
• Asbestos HVAC Ducts and Flues field identification photos and guide
• Fiberglass: Indoor Air Quality Investigations: Health Concerns About Airborne Fiberglass: Fiberglass in Indoor Air from HVAC ducts, and Building Insulation
• Enviro-Scare: Electric Power Lines, Electromagnetic Fields, Cancer Risk, & "Enviro-Scare" - The Normal Curve Cycle of Public Fear of Environmental Issues
• Dust from the World Trade Center collapse following the 9/11/01 attack: the lower floors of this building contained spray-on fire-proofing asbestos materials.
• Asbestos Information Links: Asbestos Detection, Testing, Recognition, Hazards, Field Photos, and Information Sources, including health-related links such as legal services and information about mesothelioma and other cancers.
• Asbestos Identification and Testing References
• Asbestos Identification, Walter C.McCrone, McCrone Research Institute, Chicago, IL.1987 ISBN 0-904962-11-3. Dr. McCrone literally "wrote the book" on asbestos identification procedures which formed the basis for current work by asbestos identification laboratories.
• Stanton, .F., et al., National Bureau of Standards Special Publication 506: 143-151
• Pott, F., Staub-Reinhalf Luft 38, 486-490 (1978) cited by McCrone

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