Peter, this is wrong...
These are not the official R-values for Germany. The official R-Value for
usual strawbales in Germany and Austria is 0,045 W/mK.
These are the R-Values for "Baustrohballen", special bales tested under
special circumstances.
And it is an old but wrong conclusion, that the worse R-values are more
realistic.
We developed and tested those special strawbales for the building-industry
(for prefabricated walls and roofs) in 2008/2009 again in Austria and had
much better results in 2 different official testing-institutions: 0,047 W/mK
(inluding the 20% addition) ? although there is no test-paper available yet
(we are still optimizing...).
The difference between "normal" strawbales and "Baustrohballen" is the
testing-procedure according to EU-building-codes, but it is possible to
press those building-bales for prefabrication in a whole different way, than
Dirk did. It's all about pressing the bales in the best way.
So we will have CE-certified "Baustrohballen" with nearly the same good
R-values as the R-values for normal strawbales in Austria and Germany this
summer.
Best wishes, Herbert
--
asbn - austrian strawbale network
?sterreichisches Netzwerk f?r Strohballenbau
3720 Ravelsbach, Baierdorf 6
Email:
asbn@baubiologie...http://www.baubiologie.atHi Andr?,
Below the response from Dirk Scharmer of the German Straw Bale
Building association FASBA, when I asked him to comment on the 0,045
figure I had found on their site (http://www.downloads.fasba.de/Pb-lambda1.pdf
). Dirk's basically saying that in Germany the official values to
calculate with are 0,08 (for bales flat) and 0,052 (for bales on edge)
and that these figures are 20% higher than the measured ones because
in Germany there's an obligation (for all natural fibre-based
insulation) to add 20% to compensate for the fact that the lambda test
are done on dry material whereas in the real world relative humidity
of 75-95% in the walls do mean that insulation values decrease. He
finishes with saying that these official 'calculation' values are not
as good as the Austrian ones, but more realistic (according to him).
Hope this helps.
Regards, Peter
PS: their values are valid for densities 90-110kg/m3
======================================
Laut der in Deutschland nun geltenden allgemeinen bauaufsichtlichen
Zulassung Z-23.11-1595
http://www.downloads.fasba.de/AbZ-Nr.-Z-23.11-1595.pdf gilt ein
Lambda-Rechenwert Halmrichtung von 0,08 W/mK und quer zur Halmrichtung
von
0,052 W/mK. Die jeweils tats?chlich gemessenen Werte liegen 20%
niedriger,
weil es in Deutschland einen Sicherheitsaufschlag f?r pflanzliche
D?mmstoffe
gibt (es wird im trockenen Zustand gemessen, in der Wand herrschen
aber ja
auch mal feuchtere Bedingungen von z.b. 75-95% relative Luftfeuchte, die
eine tats?chliche Verschlechterung der D?mmwirkung zur Folge haben
k?nnten).
Unsere Untersuchungen zeigen ziemlich deutlich, dass die
W?rmeleitf?higkeit
in Halmrichtung wirklich h?her ist (also die Ballen liegend schlechter
d?mmen)
Die obigen Rechenwerte von 0,052 und 0,08 sind zwar nicht so g?nstig f?r
uns, wie die ?sterreichischen sind aber meines Erachtens realistischer.
Soweit erstmal?
Gruss
Dirk Scharmer
Fachverband Strohballenbau Deutschland e.V.
Auf der Ruebekuhle 10
D- 21335 Lueneburg
Tel. 00 49 4131- 2278649
Fax. 00 49 4131- 2278648
Internet: www.fasba.de
====================================
____________________________________________________
European strawbale building discussion list
Send all messages to:
Strawbale@amper....muni.cz
Archives, subscription options, etc:
http://amper.ped.muni.cz/mailman/listinfo/strawbale
____________________________________________________