[GSBN] Clay plaster language for IBC (GSBN Digest, Vol 10, Issue 20)

[RT]

On Wed, 18 Jan 2012 12:24:12 -0500, <GSBN-request at sustainablesources.com>
wrote:

> From: martin hammer <mfhammer at pacbell.net>

> The notion that all code language should be performance-based is frankly
> nonsense.

No more nonsensical than trying to incorporate prescriptive standards for  
a material, into a Code which aspires to be used internationally, without  
first having an evaluation protocol in place which can be used to provide  
competent performance data from which a reasonable level of expected  
performance can then be selected for the purposes of prescriptive  
specification ... I would argue.

As support for that argument, I would simply point to the mess that  
surrounds the R-value of straw in American codes. Exporting that mess to  
other jurisdictions is not only undesirable, it is I hope, unlikely.

If we're talking about desired performance from a material for the  
purposes of Code specification (which it appears we are), then we're  
talking about material properties data obtained from testing (ie anecdotal  
evidence is not data). (ie Clay plaster specifications is a "clock"  
problem, not a "cloud" problem).

For the testing to be recognised as being valid internationally, a  
competent evaluation protocol needs to be utilised.

The example of specifying "20% moisture content" as proof of the utility  
of a prescriptive standard is I think, a poor one. It provides no  
assurance to a homeowner that the straw will provide a reasonable length  
of service life ... whereas requiring a certain level of performance of  
the assembly in which it is used, does.


-- 
=== * ===
Rob Tom
Kanata, Ontario, Canada

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