{"id":9286,"date":"2020-12-21T20:24:32","date_gmt":"2020-12-21T20:24:32","guid":{"rendered":"https:\/\/insulation.org\/?page_id=9286"},"modified":"2023-08-21T16:36:36","modified_gmt":"2023-08-21T16:36:36","slug":"materials-and-systems","status":"publish","type":"page","link":"https:\/\/insulation.org\/training-tools\/designguide\/materials-and-systems\/","title":{"rendered":"Materials And Systems"},"content":{"rendered":"
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Materials and Systems<\/strong><\/h2>\n

There are a wide variety of insulation materials, facings, and accessory products available for use on mechanical systems. The list changes continuously as existing products are modified, new products are developed, and some products are phased out. The task for the insulation system designer is to select the products or combination of products that will satisfy the design requirements at the lowest total cost over the life of the project. Cost is not always the deciding factor, however, as insulation systems provide needed personnel protection, save energy, mitigate environmental impacts and development of corrosion under insulation (CUI), enhance the longevity of energy equipment, and help meet return on investment goals. The design task is not easy. In most cases, the designer will find that a number of products or systems will work, and the final choice will depend on cost, availability, compatibility, ambient environmental conditions within operating areas, or other considerations.<\/p>\n

This section reviews commonly used materials and describes important performance properties. Links to data sheets for commercially available products also are provided. It is important to continually check for changes to existing products, as well as the availability of new products, that may enhance successful use and efficiency of a well-designed insulation envelope. Within the\u00a0Resource Section<\/a>\u00a0you can find listings of mechanical insulation standards and guidelines, along with Manufacturers\u2014Associate Members of the\u00a0National Insulation Association<\/a>\u00a0(NIA), categorized in the same format as materials contained in this section.<\/p>\n

Categories of Insulation Materials<\/h3>\n

Insulation materials may be categorized (Turner and Malloy, 1981) into one of five major types: 1) cellular, 2) fibrous, 3) flake, 4) granular, and 5) reflective.<\/p>\n

Cellular insulations<\/strong>\u00a0are composed of small individual cells either interconnected with or sealed from each other to form a cellular structure. The base material may be composed of glass, plastics, and rubber, and a variety of foaming agents are used.<\/p>\n

Cellular insulations are often further classified as either open cell (i.e., the cells are interconnecting) or closed cell (the cells sealed are from each other). Generally, materials that have greater than 90% closed-cell content are considered to be closed-cell materials.<\/p>\n

Fibrous insulations<\/strong>\u00a0are composed of small-diameter fibers that finely divide the air space. The fibers may be organic or inorganic, and they are normally (but not always) held together by a binder. Typical inorganic fibers include glass, rock wool, slag wool, and alumina silica.<\/p>\n

Fibrous insulations are further classified as either wool or fiber insulations. Textile-fiber insulations are composed of woven and non-woven fibers and yarns. The fibers and yarns may be organic or inorganic. These materials are sometimes supplied with coatings or as composites for specific properties\u2014e.g., weather and chemical resistance, reflectivity, etc.<\/p>\n

Flake insulations<\/strong>\u00a0are composed of small particles or flakes that finely divide the air space. These flakes may or may not be bonded together. Vermiculite, or expanded mica, is flake insulation.<\/p>\n

Granular insulations<\/strong> are composed of small nodules that contain voids or hollow spaces. These materials are sometimes considered open-cell materials because gases can be transferred between the individual spaces. Aerogel, calcium silicate, microporous, and expanded perlite insulations are considered granular insulation. It has two subcategories: Flexible and Rigid, defined below.<\/p>\n

Granular, Flexible <\/strong>insulation can be bent (flexed) without loss of strength or integrity.\u00a0 It can be supplied flat or in rolls, with or without facings. Aerogel and microporous are produced in flexible types. Flexible granular usually includes a carrier or a facing to contain or support the granular material during use.<\/p>\n

Granular, Rigid <\/strong>insulation opposes any tendency to bend (flex) under load and may lose strength or integrity when bent.\u00a0 It can be supplied as blocks or in a preformed pipe configuration.\u00a0 Calcium silicate, microporous, and expanded perlite are produced in rigid types.<\/p>\n

Reflective Insulations<\/strong>\u00a0and treatments are added to surfaces to lower the long-wave emittance, thereby reducing the radiant heat transfer to or from the surface. Some reflective insulation systems consist of multiple parallel thin sheets or foil spaced to minimize convective heat transfer. Low-emittance jackets and facings are often used in combination with other insulation materials.<\/p>\n

Another material, sometimes referred to as thermal insulating coatings or paints, is available for use on pipes, ducts, and tanks. These paints have not been extensively tested, and additional research is needed to verify their performance. While these materials are in some cases marketed as \u201cthermal insulation,\u201d it is important to remember that they are a liquid coating or paint. They are normally applied by spraying, which dries or cures, depending on the formulation, to create a protective finish of a specified mil thickness. From NIA\u2019s perspective, it is a coating or paint, and its role as such will be left to the coating or paint experts. Thus, it is not included in the scope of this guide.<\/p>\n

From an insulation perspective, thermal insulation coatings are primary used for personnel protection purposes. According to ASTM C1055, the maximum allowable surface temperature for metallic objects is 140\u00b0F.<\/p>\n

\u201cThe possibility of burn occurring depends on three primary factors: surface temperature, thermal properties of the hot surface, and contact time of the skin to the surface\u2026 Depending on the type of material of the hot object, the skin temperature can be close to or significantly cooler, after the 5-second contact time, than the temperature of the hot surface. For metal objects (which typically have high thermal conductivities), the heat transfer is rapid and will the heat the skin to within a few degrees of the temperature of the metal surface within the 5-second rule.\u201d<\/em><\/p>\n

\u2013 <\/em>From \u201cDetermination of Skin Burn Temperature Limits for Insulative Coatings Used for Personnel Protection,\u201d NACE Accepted Paper by Howard Mitschke, Mitschke Coating Consulting, LLC and George More, Mascoat.<\/em><\/p>\n

Both thermal insulation coatings and traditional insulation systems are used for personnel protection, based on many considerations and environmental conditions.<\/p>\n

Temperature Range<\/strong><\/p>\n

Insulation materials or systems also may be categorized by service temperature range.<\/p>\n

Opinions vary over the classification of mechanical insulation by the service temperature range for which the insulation is used. As an example, the word \u201ccryogenics\u201d means \"the production of freezing cold.\" However, the term is used widely as a synonym for many low-temperature applications. At what point on the temperature scale refrigeration ends and cryogenics begins is not well defined. The National Institute of Standards and Technology (NIST) in Boulder, Colorado considers the field of cryogenics to involve temperatures below -180\u00b0C. NIST based its determination on the understanding that the normal boiling points of \u201cpermanent\u201d gases such as helium, hydrogen, nitrogen, oxygen, and normal air are below -180\u00b0C, while the Freon refrigerants, hydrogen sulfide, and other common refrigerants have boiling points above -180\u00b0C.<\/p>\n

Understanding that there is variance in the accepted ranges of service temperature by which to classify mechanical insulation, the mechanical insulation industry has generally adopted the following category definitions:<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

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Category<\/th>\nDefinition<\/th>\n<\/tr>\n
Cryogenic applications<\/td>\n-50\u00b0F and below<\/td>\n<\/tr>\n
Thermal applications:
\nRefrigeration, chilled water, and below-ambient applications
\nLow to high-temperature applications<\/td>\n		-49\u00b0F to +1,200\u00b0F<\/td>\n<\/tr>\n
Refractory Applications<\/td>\n+1,200\u00b0F and above<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Insulation Forms<\/h3>\n

Several terms are used to define the shape, consistency, or flexibility of insulation products. Often, these product definitions are not mentioned in project specifications, but they are commonly used in the industry.<\/p>\n