Fourcault process the pit must be "heated back" and then the process can continue anew. Glass chemistry has a huge impact on the process since it controls the melting, forming and annealing temperatures, liquidus temperature (point where various chemicals that make up the glass start to crystallize out of the glass) and rates of change of characteristics of the glass itself. Occasionally the ribbon will break or crack, leading to failure of the drawing process. Such breaks, known as "checks" can be alleviated by using proper operating parameters. Sometimes an expedient measure, using a portable source of heat, can be used to
Heated glass system because even high e-value windows are poor insulators compared to insulated walls, and they believe heating window ejects much of the radiant heat outside. Another criticism is that this type of heating may encourage the use of larger windows in a house, making them less energy efficient. This technology has evolved since the late 1950s where it firstly evolved to be used for melting snow on glass roofs and was then effectively inverted and used as the heat source inside the building. A common commercial use of heated glass is to prevent frost from forming on the glass doors