Furnaces range from appliances in individual households to large industrial machines used for heat production and metallurgy. It is these larger industrial furnaces that require the greatest amount of care and maintenance — the walls and floors of the furnace must be clean and intact. In the case of smelting furnaces, workers must often scrape excess metal oxides off the interior surface. These furnaces may use gas, oil, coal, oxygen, or electric induction to provide the heat required to mix and refine metals.
Furnace operators, smelters, and pourers all deal with metals and other substances at extremely high temperatures. The furnaces themselves must be made out of or insulated with fireproof materials. All joints, valves, and other weak points of the furnace must similarly be insulated to prevent heat from escaping. In addition to protecting the equipment, the workers themselves must protect themselves by wearing flame-retardant clothing, gloves, and masks.
Asbestos and Furnace Operation
Asbestos has been employed as a fire retardant and insulator for centuries. It is completely resistant to flames and chemically inert. Asbestos also works as an excellent insulator for both electrical wiring and pipes. It can be weaved into fabric and used in textiles. Asbestos has an almost innumerable amount of applications, and is an excellent insulator for furnaces. By spraying asbestos on the surface, or enclosing the furnace in slabs of asbestos sheeting, the mineral can prevent excessive loss of heat. In addition, because weaving asbestos into cloth can be done with such ease, many societies used the mineral to insulate themselves in extreme environments.
Similar clothing was worn as protective gear, particularly by those working in extreme heat. Furnace workers, smelters, and pourers all engaged in work that demanded the use of such clothing and other protective gear. Scientific research show the amount of asbestos fibers released by asbestos clothing into the air is quite significant. Moreover, when asbestos fibers are broken off, currents of warm air tend to keep the fibers airborne for longer periods. For those in the furnace, smelting, and pouring business, this was especially pernicious given that many of these buildings were not well ventilated. In other cases, binding agents were used to prevent the fibers from becoming airborne, but these agents were often rendered inert by the high temperatures associated with the job. Whatever sloughed off asbestos fibers were not inhaled could easily cling to skin and hair and transported to the worker’s home.