>>Doesn't ASTm 
>> bitch about non-reproducible  results? 

I am relatively new to the ASTM process, but it is my understanding that a 
number of standard test methods have been dropped over the years due to poor 
reproducibility. Still, there are others, like the Tape Adhesion Test, which 
although highly variable, imprecise and subjective, are still considered so 
much more useful than the alternative of nothing at all that they remain on 
the books with long rationale statements discussing their limitations.

A popular silicate coating also 
>> tested by DL outide of the  SWR program came in at 18 perms, and that 
>> manufacturer claims something like  98 or 99% breathability. 

So 18 
>> perms is like an open window?  
Nope. Next big issue is that different methods of testing vapor permeability 
may yield results that have no way of being correlated. I think the % 
breathability numbers are extremely misleading, though easier to conceptualize 
than the perm values.

Mike E.

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