What is fiberglass insulation? Fiberglass is made from molten sand or recycled glass and other inorganic materials under highly controlled conditions.

Fiberglass is made from molten sand or recycled glass and other inorganic materials under highly controlled conditions. It is categorized within a group of man-made materials referred to as man-made mineral fibers, man-made vitreous fibers, or more recently, as synthetic vitreous fibers. Vitreous refers to the glassy, non-crystalline nature of the material. Fiberglass is non-combustible and will not support the growth of mildew, mold or bacteria when tested in accordance with the specifications of the American Society for Testing and Materials (ASTM C665). Fiberglass is generally produced in two basic forms: wool-type fibers, referred to most commonly as glass wool or fiber glass insulation; and textile fibers, produced in long, continuous strands and filaments. Glass wool fibers are those used for insulation products. Fiberglass wool insulation is produced primarily through a rotary process, similar to that used for making cotton candy. First, sand and recycled glass are melted. Then molten glass is poured onto a rapidly spinning disc that has thousands of fine holes in its rim. Centrifugal force slings the molten glass throughthese holes, creating glass fibers. Also, some specialty glass wools are produced by pouring molten glass through a stranary die into fibers. The fibers are elongated by jets of air, steam or flame. Typically, but not always, the fibers are then coated immediately with a chemical binder, which holds the fibers together. The product is then cured in ovens and formed into the familiar insulation batts and blankets or chopped into loose-fill insulation used in homes and commercial buildings.