Civil Engineering Reference
In-Depth Information
Fig. 13 Illustrative production line for short fibre bale. P1 opening and pretreatment, P2
decorticating, P3 shaking sieve
4 Vegetable Fibrous Materials Characteristics
and Properties
''Characteristics and properties'', here, refer to the insulation performances of the
vegetable fibres. The characteristics and properties of vegetable fibres are strongly
influenced by many factors, e.g., chemical composition, internal fibre structure, such
as microfibril angle and cell dimensions, which differ from different parts of a
vegetable as well as from different species of vegetables (Dufresne
2008
). We
should always bear in mind that the manufacturing process also affects the properties
of the raw materials. As a result, the overall insulation performances of vegetable
fibres are determined by the combined effects of these properties and many other
unknown and uncontrollable factors. The resulting insulator can display a wide
range of properties; however, some common features are highly conserved. The
following subsection describes these common properties together with key criteria
for assessing building insulation sustainability associated with vegetable fibres.
4.1 Requirements of Insulations
The sustainability criteria by which the insulations are measured cover two main
criteria: reducing both energy demand and environmental impacts. Both elements
are essential to achieve the overall sustainability performances of the products.
The primary energy requirements of the commonly used insulation materials are
the measures of materials' technical performances based on the physical proper-
ties. Many standards are available today, such as EN and ASTM, for general
guidance. Some of the key properties are presented in (ISO 6946:2007,
1996
).
The primary environmental requirements of the commonly used insulation
materials are the measures of materials ''ecological performances'' based on the
properties which can in principle be assessed in a wide variety of ways, and hence
are not clearly stated and even less commonly accepted (Papadopoulos 2005).
Some of the key properties include the primary embodied energy, the gas emis-
sions, the waste treatment, the re-usability or the recyclability, which are associ-
ated with a range of health effect assessment including dust and fibres emissions,
biopersistence and toxicity. A number of standards have been adopted. However,
there has not been any consensus about the criteria. Nevertheless, these criteria
