Civil Engineering Reference
In-Depth Information
Aluminium
Aluminium normally has 0.9-1.4 per cent manganese in it. The products are
often covered with a protective coating through anodizing. They can also be
painted with special paint. They should not be used in combination with copper
or concrete.
Copper
Copper is produced in a pure form without any surface treatment or other
alloyed metals.
Zinc
Zinc is usually used in an alloy of zinc, copper and titanium. This should not be
used in combination with copper. Its surface is painted with a special paint.
Lead
Lead is soft and malleable. It should not be used in combination with aluminium.
In terms of raw materials the use of metals should be reduced to a minimum.
These details of the building are very much exposed to the climate and therefore
to deterioration. Zinc corrodes quickly in an atmosphere containing sulphur
dioxide, which is common in towns and industrial areas; the spray of sea salt also
causes corrosion, so it is best used away from the coast. The zinc coating on gal-
vanized steel is exposed to the same problems, but its durability is better in the
long run. In particularly aggressive atmospheres even aluminium, lead and
stainless steel will begin to corrode.
Metals have a high primary energy consumption and a polluting production
process. For the people using a building, metals are neutral, even though a high
percentage of metal is assumed to strengthen the building's internal electromag-
netic fields. Metal ions may also be released into the soil around the building.
This could cause an environmental problem, depending on the amount and type
of metal in question - lead and copper are the most troublesome. Metal can be
recycled when it becomes waste.
The use of metals should be reduced to a minimum and alternatives used
where possible. Guttering, for example, can be made of PVC or wood (see Figure
14.5). The use of metal sheeting can be reduced or avoided in many cases by
choosing other detailing.
Materials based on non-metallic minerals
Many loose mineral materials contain natural pores which make them useful as
thermal insulation. Examples are fossil meal, perlite and vermiculite.
