Agriculture Reference
In-Depth Information
polypropylene has been obtained from the
Ecoinvent
© database.
resistance of 2.36 m
2
K/W for 1 year. The life
expectancy used for this product is 1 year.
The system studied included the produc-
tion of the raw materials, the creation of the
its life. In the absence of a known, well-identi-
fied outcome, it has been assumed that the
construction waste will be stored at a landfill
site (Class II (CET II)), with the transportation
fragmented over the entire life cycle.
We have not included inputs whose mass
is inferior to 2% of the total mass of the inputs
(NF P01-010) and, in the absence of data on
the breakdown of cement and wood in CET II,
the end of life is restricted to the demolition
waste and the emissions arising from transpor-
tation of that waste to the nearest CET II. The
reuse or recycling of the hemp cement has not
been factored in.
IMPACT EVALUATION AND INTERPRETATION OF THE LIFE
CYCLE
.
The results demonstrate that hemp
fibre reduces the potential negative impact
associated with polypropylene. Thus, the pro-
duction of 1 kg of polypropylene containing
30% hemp consumes 67 MJ of non-renewable
energy and contributes between 0.7 and
1 kg CO
2
eq to the greenhouse effect,
depending on whether an economic alloca-
tion or allocation by mass is used. The energy
consumption and the impact on the green-
house effect are 20-40% lower than that
which would result from the production of
pure polypropylene.
Furthermore, the production of polypro-
pylene calls on large quantities of fossil
resources, including natural gas (0.73 m
3
/kg),
coal (63 g/kg) and uranium (5 mg/kg). In terms
of eco-planning and -design, the use of materi-
als containing renewable carbon and with the
same technical properties as polypropylene
has the potential to improve further the envi-
ronmental credentials of compounds contain-
ing hemp fibres. The results of this comparison
are presented in Table 21.6.
INVENTORY ANALYSIS
.
The organization of the
production line, the distances over which the
raw materials are transported and the quanti-
ties of the inputs (energy, materials) used in the
reference scenario described above are sup-
plied by BCB-Lhoist and
Construire en
chanvre
.
The analysis of the inventory of hemp
straw was provided in the previous section.
That of Tradical 70© (lime, hydraulic binder)
and the wood used for the frames are provided
by the
Ecoinvent
© database.
Construction using hemp
LIMITS OF THE SYSTEM STUDIED
.
The study was
undertaken for a wall of hemp cement on a
wooden frame, used as a weight-bearing wall.
It has a surface area of 1 m
2
, a thermal
IMPACT
EVALUATION
AND
INTERPRETATION
OF
THE
CYCLE
.
The results demonstrate a
LIFE
Table 21.6.
Potential environmental impacts of 1 m
3
of a thermoplastic compound containing hemp
fibres compared with a thermoplastic compound containing polypropylene only and a thermoplastic com-
pound containing glass fibre.
Thermoplastic compound
Environmental impact
Containing hemp fibre
Polypropylene
Containing glass fibre
Exhaustion of resources (Sb eq)
23.1
32.2
35.5
Atmospheric acidification (kg SO
2
eq)
14.6
19.7
23.8
Greenhouse effect (kg CO
2
eq)
950
1970
2680
Of which carbon storage (in kg CO
2
eq)
−543
0
0
Ozone layer (kg CFC-11 eq)
0.000227
0.000194
0.000308
Photochemical ozone (kg C
2
H
4
eq)
0.483
0.662
0.813
Non-renewable energy (MJ)
63,100
82,400
93,700
Air pollution (m
3
)
34,600
34,900
105,000
Water pollution (m
3
)
166
151
482
