Author(s): H. Tributsch & S. Fiechter
The fire protection of organic building and thermal insulation materials is a
technical challenge, for which new approaches are desirable.
resistant tree barks from trees such as Sequoiadendron giganteum, Pinus
canariensis and from Eucalyptus species, which evolved in fire adapted
eco-systems, were studied by thermo-gravimetric techniques in combination with
mass spectroscopy and complementary analysis in a temperature range up to
It turned out that while a technical reference poymer (ABS = acrylnitrilebutadien-
styrole) burned by leaving only 2.6% solid, the most fire resistant tree
barks only carbonized leaving up to 60% solid.
It is mostly graphite and carbon,
which are highly heat insulating and fire protecting as is also known from
technical “foaming” graphite layers.
A key chemical component that has evolved
in tree barks to support fire resistance, besides other properties, is tannin, a
polyphenol, which complexes macromolecules and efficiently reduces oxidants
The oxidation, in a fire, of these large planar molecules is thus
suppressed to be transformed into a similarly structured graphitic component
with fire retarding properties.
Additional adaptations of fire resistant tree barks
appear to be a fibrous micro- and nano-structure and optimised infrared optical
They may retard heat transfer within the bark via suppression of
microscopic conduction and radiation processes.
fire retardation, tree barks, tannins, sequoia, eucalyptus.
Significant scientific and technological effort is presently ongoing with the aim
of meeting the more and more demanding standards of fire protection when
organic and plastic materials are used in our technical environments.
Size: 892 kb
Paper DOI: 10.2495/HPSM080051
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