Cob Re: fibrous cement - K-VALUE?!

[Patmon, Steve]

Hi Epko,

A k-value or factor is relative to the thermal conductivity of a material
from one side to the other.  A long definition follows;

Thermal conductivity:
The rate of tranfer of heat by conduction; the amount of heat per unit of
time per unit area that is conducted through a slab of unit thickness of a
material if the difference in temperature between opposite faces is one
degree of temperature; a property of the material itself, usually
represented by the letter k and called a k factor.

Therefore in cob application it is the amount of heat transferred from the
outside to the inside in a matter of time.  But it is relative to the
thickness of material.  How long does it take the temperature to be
transferred through a material thickness with only a loss of one degree of
temperature.  Please note that in my field it is rare that we refer to the
k-value.  Mostly because insulations relate their qualities based upon
resistance rather than conductance.  In this case the manufacturer is giving
you this value relative to the r and u values.  They are relative to each
other.  You should normally be able to find a k-value with most construction
materials which have some type of mass ie., CMU block, Concrete, Cement, Cob
(if it ever becomes massed produced). 

Hope it helped

Steve
> -----Original Message-----
> From:	M J Epko [SMTP:duckchow at mail2.greenbuilder.com]
> Sent:	Friday, July 24, 1998 1:18 AM
> To:	coblist at deatech.com; strawbale at crest.org
> Cc:	earth at zianet.com
> Subject:	Cob Re: fibrous cement - K-VALUE?!
> 
> *laughing* ... ya got yer R-Value, ya got yer U-Value... what the hell's a
> K-Value?! It's those metric-speakers - from the UK, y'know...
> 
> Blue light special on left-field slips, aisle 14.
> 
> 
> 
> 
> Happy Birthday to SB Listmonkey Matt Kitterman.
> 
> 
> 
>    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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>     M J Epko - duckchow at mail2.greenbuilder.com
>                Kingston, New Mexico
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