[CAUT] RH? Please enlighten me.

[Alan McCoy]

Here are an EMC table and excel EMC calculator attached. Maybe they'll get
through the filters.

Alan


-- Alan McCoy, RPT
Eastern Washington University
amccoy at mail.ewu.edu
509-359-4627
509-999-9512


> From: Jim Busby <jim_busby at byu.edu>
> Reply-To: "College and University Technicians <caut at ptg.org>" <caut at ptg.org>
> Date: Tue, 09 Dec 2008 17:14:32 -0700
> To: "College and University Technicians <caut at ptg.org>" <caut at ptg.org>
> Subject: Re: [CAUT] RH? Please enlighten me.
> 
> Thanks Don, all. Very enlightening.
> 
> Don, this paragraph from you helps me better understand the "why" of cracked
> soundboards. We really have been lucky here at BYU to not have more problems.
> 
> Jim
> 
> From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of Don
> Mannino
> Sent: Tuesday, December 09, 2008 12:41 PM
> To: caut at ptg.org
> Subject: Re: [CAUT] RH? Please enlighten me.
> 
> <<<My little quick rough guideline I try to give piano dealers and schools for
> soundboard health is the following: if you hold a room at 22ºc and 25%, the
> Spruce in the soundboard will be dried to about 5% EMC (very roughly - it does
> vary by species and density).  So when the humidity goes below 20% at
> comfortable room temperatures, then the soundboard is being dried down farther
> than the factory did originally, and the chance of cracks opening up is very
> high.  Some soundboards can handle this better than others, but eventually
> they will seek relief from the shrinkage and will need to crack.>>>
> 
> Don
> 

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