Manufacturers say that an average furnace averages 12 to 15 years between rebuilds, with seven years as a worst-case situation. Walker explains that at up to $150 million for directory signs production of a brand new manufacturing site and $10 million to $15 million for a new furnace or rebuild, extending furnace life translates without delay into greenbacks.

The industry takes 3 most important techniques to glass melting: (1) oblique soften (also known as marble remelt); (2) direct soften the usage of larger-scale furnaces (8,000 to a hundred,000 metric tonnes consistent with year); and (three) direct soften the use of smaller-scale furnaces (150 to 200 metric tonnes according to 12 months), which are additionally known as paramelters. For oblique marble remelt, molten glass is sheared and rolled into marbles roughly zero.62 inch (15 to 16 millimeters) in diameter, which are cooled, packaged after which transported to a fiber manufacturing facility in which they are remelted for fiberization (see “Step 3”). The marbles facilitate visible inspection of the glass for impurities, ensuing in a more constant product. The direct soften method transfers molten glass within the furnace directly to fiber-forming device. Because direct melting removes the intermediate steps and the cost of forming marbles, it has come to be the most widely used approach.