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The barrier properties and heat reflectivity of aluminium foil are widely used in building panels adding to the insulation performance of modern building systems. Aluminium foil is also used as a skin for heat-insulating and incombustible materials to provide high performance insulation for pipework and ducting. The adhesive tape used to secure the laminated material is also based on aluminium foil for its reflective surface, corrosion-resistance and long life.
In electrical cables, aluminium foil helps to give long-term insulation against moisture and attack from naturally occurring corrosive elements found above and below the ground.
Aluminium foil also acts as an insulator against the magnetic and radio frequency emissions associated with electrical cables. As a sheath for fibre-optic cables, aluminium foil uses its electrical conductivity to act as a ‘tracer’ to enable testing of the integrity of cable links - as well as helping to provide the long term protection every cable needs.
In ‘fire walls’ for vehicles and fire-proof doors and building panels, aluminium foil stops access to the oxygen required to support flames.
Heat Exchangers
Aluminium has, over the past few years, virtually replaced copper as the preferred metal for use in heat exchangers. Aluminium alloys offer excellent heat conductivity combined with much less weight, which is very important in every automotive situation. Considerable development work on alloys, brazing and other joining methods as well as the introduction of ‘clad’ materials combining strength with ease of joining have brought success for aluminium.
The special alloys used are supplied to manufacturers of heat-exchange units in a wide variety of thicknesses and widths. Starting at 50µm the foil material goes up to a thickness of 250µm (a little over the strict ‘foil’ thickness designation). Brazing strip used in heat exchangers is a similar, but thicker material with thicknesses rising to 2mm.
Aluminium foil has enabled car manufacturers to save considerably on the weight of a car's radiator. This, in turn, saves on the fuel demands of the vehicle, so reducing emissions. The air conditioning now standard equipment in most passenger cars also uses aluminium foil for the heat exchanger finning.
It is not just in cars that aluminium heat exchangers are to be found - everywhere that heating or cooling is necessary. In the air conditioning of shops and offices, theatres, ships, refrigerated trucks, trains and so on, there is a place for the economy and efficiency the aluminium foil-finned heat exchange unit.
Automotive Applications
Aluminium foil is also increasingly important in automotive components such as impact energy absorption structures and in catalytic converters. Favoured over steel because of better corrosion resistance and weight economy, special aluminium alloys provide the physical properties required in these aluminium foil applications.
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