Since the beginning of civilization, humans have recognized the need for insulation. Man clothed himself with wool and skins from animals. He built homes of wood, stone, earth, and other materials for protection from the cold winter and the heat of summer.
Ancient Greeks and Romans discovered asbestos and found many uses because of its resistance to heat and fire. The Romans used cork for insulation. One use was in shoes, to keep their feet warm. As industrialization expanded, cork was used as an insulation for ice houses. Blocks of ice were cut from frozen lakes in winter and stored in cork-lined ice houses for use in summer. When mechanical refrigeration came into use, cork was used to insulate pipes and equipment.
Mineral fiber - another important insulating material - was first used by the natives of the Hawaiian Islands to blanket their huts. The fibers came from volcanic deposits where escaping steam had broken the molten lava into fluffy fibers.
Man-Made mineral fibers were developed in the early industrialization period. Steam was injected into molten slag, a waste product from iron furnaces. It has been widely used for both building and industrial insulation. As more and more uses were found for it, mineral fibers were modified and molded into different shapes such as pipe covering.
A pipe covering made from corrugated layers of asbestos paper was developed for hot applications. This type of insulation obtained its efficiency from air pockets in the corrugation. The development of the more efficient fiberglass made this material obsolete.
Another obsolete material widely used for many years was 85 percent magnesia. This material was similar to the calcium silicate used today but it contained asbestos fibers as a binder. This material was used extensively until the mid-fifties when calcium silicate made it obsolete.
Materials made from layers of high-fiber-content felt or paper, with layers of asphalt saturated felt formerly were used on moderate-to-cold temperature applications.
Today materials manufactured from fiberglass, ceramic, mineral wool, calcium silicate, foamed plastic, glass, and other substances are used in many shapes and forms. The most widely used material is fiberglass which is available in loose fill, blanket, board, and molded pipe shapes.
Insulation uses range from conventional building and pipe insulation to insulation for equipment and systems operating at extremely low or high temperatures. Insulation is a vital part of industry. It is used in many ways and forms to improve our environment. Its importance will continue to increase as technology advances and energy resources and conservation are high priority.