Thermal insulation materials are specifically designed to reduce the heat flow by limiting heat conduction, convection, radiation or all three while performing one or more of the following functions.
Conserving energy by reducing heat loss or gain
Controlling surface temperatures for personnel protection and comfort
Facilitating vapor flow and water condensation of a process
Increasing operating efficiency of heating/ventilating/cooling, plumbing, steam, process and power systems found in commercial and industrial installations
Assisting mechanical systems in meeting standard criteria in food and cosmetic plants
There are three general material types into which thermal insulation materials can be categorized.
Fibrous insulations are composed of small diameter fibers which finely divide the air space. The fibers may be perpendicular or parallel to the surface being insulated, and they may or may not be bonded together. Silica, glass, rock wool, slag wool and alumina silica fibers are used. The most widely used insulations of this type are
glass fiber and mineral wool.
Cellular insulations contain small individual cells separated from each other. The cellular material may be glass or foamed plastic such as polystyrene (closed cell), polyurethane, polyisocyanurate, polyolefin, or elastomer.
Granular insulations have small nodules which contain voids or hollows. These are not considered true cellular materials since gas can be transferred between the individual spaces. This type may be produced as a loose or pourable material, or combined with a binder and fibers to make a rigid insulation. Examples of these insulations are calcium silicate, expanded vermiculite, perlite, cellulose, diatomaceous earth and expanded polystyrene.
Our previous article OVERVIEW OF INSULATION SYSTEMS in our article titled insulation system, South Africa ve temperature band information about the