Monday, September 21

While fiberglass insulation is not traditionally thought of as a non-woven product, it most certainly fits into that category. This presentation will be a broad overview of the products, product design, and markets for light density fiberglass batts and rolls produced for residential construction in the US market. It will include a discussion of customers, their expectations, and their applications. It will go over the basics of product design including the effects of fiber characteristics, density, thickness, and temperature. Performance requirements will be discussed along with test methods. Finally, we will cover thermal and acoustical performance, health and safety, and the many _green_ aspects of this product family.

Heat is transferred by conductive, convective and radiative mechanisms. These are often lumped together in a concept called apparent heat conductivity and treated by the methods used in heat conduction. The lower limit of heat conductivity for insulating fabrics in air, is the conductivity of quiescent air (perhaps with an exception where the pore dimensions are less than the mean free path of air molecules). The apparent thermal conductivity of nonwoven mats of a single type of fiber have been found to have a linear relationship with the fabric specific volume (within the range of specific volumes typically used for fibrous insulation). The extrapolated value of thermal conductivity at zero specific volume is the thermal conductivity of quiescent air. The “slope” of the line is a characteristic of the fabric composition and can be used to calculate the cost/area of the insulation. The results suggest that convection is easily interrupted, and heat transfer is not highly affected by the material of construction (at typical densities). The major paths of heat transfer through fibrous insulation is conduction through quiescent air and radiation through the volume of the insulation. The major differences between various fibrous insulation products are their thickness and their ability to interrupt radiative heat transfer.

The use of mineral fiber insulation products (fiberglass and rock wool) is pervasive throughout much of the world. With the exception of a relatively recent episode of Modern Marvels_, the insulation manufacturing process has been relatively unknown to many. This paper will explore the manufacturing process of insulation from soup to nuts. Starting with the melting of glass and rock through the fiberizing processes, the technologies employed are unique in some respects and similar in others to organic fiber technologies in use today. Likewise batt forming and curing are based on traditional methods, but have some unique attributes when compared to current nonwoven manufacturing. In essence the volume of fiberglass and rock wool insulation made in the world today makes up a large percentage of the total nonwovens volume, but the technology surrounding manufacturing processes is relatively unknown.