| Aluminium
alloy, used in the production of profiled roof
and wall cladding panels, is AA 3105, which
conforms to BS 4300/6 Alloy NS31, and DIN 1725
Alloy AL Mn 0.50 mg 0.50. Material
Properties Ultimate Strength: Min 200 N/mm2 yield
strength: Min 180 N/mm2 Modules of elasticity :
70000 N/mm2 Coef. of thermal expansion : 24 x
10-6
Durability
When exposed to the atmosphere natural aluminium
forms a thin layer of protective oxide coating on
tis surface. Thanks to this composition, the
roofing element is adequately protected against
corrosion undeer normal conditions of exposure to
atmospheric conditions, especially in coastal and
industrial area.
Fire:
Aluminium is classified as a non-combustible
material, as defined by BS 476:part 4:1970. Roof
coverings of aluminium alloy are rated EXT AA
when tested in accordance with BS 476: part
3:1958.
Combining
with other material, these roof coverings can
come into direct contact with plastics,
galvanized steel, high-grade and pre-painted
steel and zinc sheets.
Direct
contact with ordinary steel, copper, brass and
lead should be avoided by introducing a
continuous seperating element such as PVC tape,
or bitumen felt strips, or, alternatively,
painting with zinc chromate or aluminium paint.
This also applies to direct contact with mortar
and concrete.
Timber
parts which come into contact with aluminium
should be treated with impregnating agents which
do not contain copper salts, mercury salts,
phenol compounds or fluorine compounds.
Finishes
Mill Finish:This is the natural untreated surface
of the metal as it leaves the rolling mill.
Stucco-embossed
aluminium is mill-finished aluminium. This is
roller-embossed to produce an irregular raised
pattern finish. The advantage of embossing is
that direct reflections and sun glaze are
diffused, without reduction in the total
reflectivity.
Polyester
colour-coated an economical, long-life coating,
factory applied polyester on the exposed side,
and a lacquer coating on the reverse side. This
is available in RAL as well as BS colour shades.
PVF2
colour-coated excellent U.V.resistance, long-life
coating of 2 coats of factory applied PVF2 on the
exposed side and a lacquer coating on the reverse
side. Available in RAL as well as BS colour
shades.
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