Page 49 - Kutnar, Andreja, et al., eds., 2015. Proceedings of the 1st COST Action FP1307 International Conference - Life Cycle Assessment, EPDs, and modified wood. University of Primorska Press, Koper.

use
of
modified
wood
in
Slovenia

Manja
Kitek
Kuzman1,
Mirko
Kariz2

1
Department
of
Wood
Science
and
Technology,
Biotechnical
Faculty,
University
of

Ljubljana,
C.
VIII/34,
1001
Ljubljana,
Slovenia;
manja.kuzman@bf.uni-­‐lj.si

2
Department
of
Wood
Science
and
Technology,
Biotechnical
Faculty,
University
of

Ljubljana,
C.
VIII/34,
1001
Ljubljana,
Slovenia;
mirko.kariz@bf.uni-­‐lj.si

Keywords:
heat
treated
wood,
timber
housing,
claddings

The
use
of
wood
as
a
building
material
is
increasing
due
to
increasing
awareness
of
its

mechanical
and
ecological
properties.
New
processes
were
developed
to
improve
some

properties
of
wood
and
wood
composites
without
diminishing
its
environmental
impact.

Heat
treatment
is
a
process
used
to
modify
the
properties
of
wood.
It
improves
its

dimensional
stability,
resistance
to
biological
attack,
and
thermal
performance
by

exposing
wood
to
elevated
temperatures
ranging
from
160
°C
to
260
°C
with
different

procedures
(Militz
2002,
Hill
2006).
Thermal
treatment
avoids
the
use
of
wood

preservatives
and
represents
an
attractive
“non
biocidal”
alternative
to
classical

preservation
treatments
and
broadens
the
usage
of
non-­‐durable
local
species
in
place
of

more
durable
(imported)
species.
Modified
wood
is
ideal
for
use
as
a
cladding,
terrace

flooring,
railings,
windows,
doors,
and
anywhere
wood
is
exposed
to
the
environment,

but
not
loaded.
In
Slovenia
there
are
two
manufacturers
of
the
thermally
treated
wood:

Silvaprodukt
d.o.o.
Ljubljana,
and
I-­‐les
Iskra
d.o.o.

Silvaprodukt
uses
a
process
they
developed
and
patented
and
trades
its
product
as

Silvapro
wood.
The
process
uses
a
special
modification
chamber,
where
modification

starts
with
an
initial
vacuum
phase.
This
provides
a
low-­‐oxygen
inert
atmosphere
during

modification
and
reduces
wood
degradation
at
elevated
temperatures.
The
chamber

capacity
is
4
m³
and
the
treatment
time
per
cycle
is
from
18
to
36
hours,
depends
on
the

thickness
of
wood
and
desired
treatment
temperature
(170
°C
to
230
°C).
The
annual

output
is
around
1,200
m³.

The
other
manufacturer,
I-­‐Les,
uses
Wood
Treatment
Technology’s
(WTT)
process.
The

chamber
capacity
is
around
4
m³
and
uses
treatment
temperatures
around
160
°C
to

180
°C.
The
processes
differ
in
number
of
steps
of
modification,
temperatures,
duration,

pressures,
and
conditioning
at
the
end
of
the
process.

37