[Strawbale] SB R-values

[Peter van Balen]

Hi André,

At FASBA's site, I found (http://www.downloads.fasba.de/oeffentlich/pruefzeugnisse/z-23.11-1595(2009).pdf 
) the values 0,052 resp 0,080 for straw bales 'on edge' resp 'laying  
flat' (scroll down to page 5) that I mentioned before, and this  
document is dated (and stamped!) Feb 13th, 2009.
Could anyone confirm the right figures, please??

Regards and good luck with your numbers!
Peter

>
>
> 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 at baubiologie...
> http://www.baubiologie.at
>
>> Hi 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
>> ====================================
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>

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