Borates are an important ingredient in insulation fiberglass, which represents the largest single use of borates worldwide. Insulation fiberglass is also known as glass wool or mineral wool, although the latter term also covers stone and slag wool which does not contain borates.

Insulation fiberglass is used for thermal and acoustic insulation, with the largest use by far the thermal insulation of residential and commercial buildings. Here it plays an important role in reducing energy use and carbon dioxide emissions from the built environment. In buildings, insulation fiberglass may be used in the form of blankets (rolls) batts (pre-cut slabs) or loose fill (blowing wool). More minor uses of insulation fiberglass include duct and pipe wrap for refrigeration, heating, ventilation and air conditioning systems.

Insulation fiberglass works by trapping air within its mesh of fibers to reduce the rate of heat transfer. The most important role of borates in the glass fibers is to increase absorbance of infrared radiation, which significantly increases the insulation performance of the roll, batt or wool. In insulation fiberglass manufacturing, borates act as a powerful flux and lower glass batch melting temperatures. They also control the relationship between temperature, melt viscosity and surface tension to create optimal glass fiberization. The end result is short, strong fibers that are biosoluble (dissolve in the lung if inhaled during installation), and resistant to water and chemical attack.


Glass and Ceramics Development Specialist

Andrew Zamurs

Andrew has worked at Rio Tinto Borates for 5 years, focusing on development of glass and ceramics. He attended Clarkson University.