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General comment Allocation is required if some material, energy, and waste data
cannot be measured separately for the product under investigation.
In this study, as per EN 15804, allocation is conducted in the
following order;
1. Allocation should be avoided.
2. Allocation should be based on physical properties (e.g. mass,
volume) when the difference in revenue is small.
3. Allocation should be based on economic values.
Module A1 includes allocation for co-products. Allocation has been
done based on economic values as the Products and co-products
share of revenue differs greatly.
Allocation used in Ecoinvent 3.6 environmental data sources
follows the methodology ‘allocation, cut-off by classification’. This
methodology is in line with the requirements of the EN 15804 -
standard.
This LCA study is conducted in accordance with all methodological
considerations, such as performance, system boundaries, data
quality, allocation procedures, and decision rules to evaluate inputs
and outputs. All estimations and assumptions are given below:
• Module A2, A4 & C2
Vehicle capacity utilization volume factor is assumed to be 1 which
means full load. In reality, it may vary but as role of transportation
emission in total results is small and so the variety in load is
assumed to be negligible. Empty returns are not taken into account
as it is assumed that return trip is used by transportation company
to serve the needs of other clients.
• Module A3
Waste wood used for drying kilns was allocated based on share of
wet wood used for each Product. All other energy use and waste
was allocated based on production volume.
• Module A4
The transportation distance is defined according to RTS PCR. The
typical installation place was assumed as an average option.
According to the manufacturer, transportation doesn’t cause losses
as products are packaged properly. Also, volume capacity utilisation
factor is assumed to be 1 for the nested packaged products.
• Module A5
Consumption of energy in installation process are assumed to be
38 MJ of diesel per m3 of CLT and glulam. Metal fasteners are
assumed to be used in the amount of 4.5 kg (CLT), 16.5 kg (glulam)
and 4 kg (finger-jointed structural timber) per 1 m3.
• Module C1
Consumption of energy in demolition process is assumed to be 38
MJ of diesel per m3 of product. It is assumed that 100% of the
waste is collected. Fasteners are excluded.
• Module C2
It is estimated that there is no mass loss during the use of the
product, therefore the end-of-life product is assumed to have the
same weight with the declared product. All of the end-of-life
product is assumed to be collected as sorted wood waste or mixed
construction waste and sent to the closest facilities such as
recycling and landfill. Transportation distance to the closest disposal
area is estimated as 250 km and the transportation method is
assumed as lorry, which is the most common option.
• Module C3
97% of the sorted wood waste is recycled. Losses in the sorting
process are assumed to be very small and not considered in the
assessment.
• Module C4
The remaining 3% of the sorted wood and 100% of the mixed
construction waste are assumed to be sent to landfill.
• Module D
Benefits of recyclable waste generated in the Module C3 are
considered. It was assumed that 47.49% of the sorted wood waste
is incinerated and 49.47% is recycled to be used again (for example,
to produce fibreboard).
The study does not exclude any modules or processes which are
stated mandatory in the EN 15804:2012+A2:2019 and the applied
PCR. The study does not exclude any hazardous materials or
substances.
The study includes all major raw material and energy consumption.
All inputs and outputs of the unit processes, for which data is
available for, are included in the calculation. There is no neglected
unit process more than 1% of total mass or energy flows. The
module specific total neglected input and output flows also do not
exceed 5% of energy usage or mass.
Cut off has been applied only in C1 to exclude fasteners.
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