Page 197 - Materials Chemistry, Second Edition

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Sustainable Industrial Design and Waste Management
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that are using up to 98% post-consumer waste glass in their product. The
basic principle of foam glass manufacture is to generate a gas in glass at a
temperature between 700°C and 900°C. The gas expands thus producing
a structure of cells to form a porous body. The foam glass can be either made
from molten glass or sintered glass particles. The latter process requires
ground glass to be mixed with a foaming agent, then on heating the foaming
agent releases a gas and expands the molten glass mass.
The main foam glass producers in Europe, Japan, and North America now
use a high percentage of processed post-consumer glass in their products.
Currently, there are three main product types of foam glass:

• Loose foam glass aggregate: Continuous production of sheets of foam
glass that are then broken into loose foam glass aggregate and sized.
• Blocks and shapes: Generally continuous production of blocks and
shapes in molds that are then cut and shaped. Can also be manufac-
tured by a batch process.
• Pelletization: Continuous production of spherical pellets of foam glass
that are then used in the manufacture of blocks, panels, and slabs.

Foam glass is best suited as a rigid insulation material. Due to its excellent
structural properties, it is suitable for use as insulation in roofs, walls, and traf-
fic areas such as flat roofs or floors, where other insulation products may be
compressed resulting in an uneven surface and the loss of insulating proper-
ties. Foam glass has excellent fire resistant properties and its very low water
absorption and water vapor transmission means that, unlike many other types
of insulation, it tends to retain its insulating properties even when wet. It is
also used as industrial insulation for a number of minor uses such as sand-
wich panels or is used as a product in extreme environmental conditions.
Foam glass has been manufactured for a number of years mainly in the
USA and Europe as a lightweight high strength insulating material. The main
driver for foam glass use has been the requirement of high energy efficiency
standards for building construction which deals with energy conservation.
The basic building block of all these regulations is the value of the overall
heat transfer coefficient. This is the rate of heat loss, expressed in watts per
2
square meter per degree temperature difference (w/m K). The use of foam
glass in the construction of housing and buildings could greatly reduce energy
consumption.
In addition to the potential energy saving from the use of foam glass,
there are other less obvious advantages due to the lightweight nature of the
material. These include design flexibility, construction productivity, reduced
manual handling, lower transport costs, and lower foundation costs. Also it
is rodent resistant, fire resistant, an effective sound absorber, non-toxic, and
non-water absorbent.
Foam glass as a building construction material is in competition
with insulating polymeric and fibre materials as it is a good insulator.