What are the "safe" parameters for shop humidity?

[Farrell]

IMHO, good humidity control is critical. I would say that anything between 40% and 50% would be excellent and constant RH is perhaps more critical than any particular level. At 60,000 sq ft., I'm sure you can run down to Sears and pick up a suitable dehumidifier for about $435,000. OR, you may wish to consider partitioning off a unit in the 1,000 to 2,000 sq ft. range (or whatever size you need) and go for the $150 variety humidity control device! I wouldn't take much to partition off - a bunch of 2x4s (or maybe even smaller?) and plastic or foil-backed foam insulation and you'd be good to go.

I keep my shop right between about 45% and 48% RH (little Sears basement-type dehumidifier in 950 sq. ft. shop) and keep at least a six-month to year supply of wood (maple, spruce, etc. - actually I likely have several years worth of most wood). It is a very comfortable feeling to know that all the wood that I put into pianos is going to be very stable and I don't have to worry about dimensional changes, warping, etc.

Terry Farrell
  
----- Original Message ----- 
From: "gordon stelter" <lclgcnp@yahoo.com>
To: "Pianotech" <pianotech@ptg.org>
Sent: Wednesday, August 20, 2003 10:32 PM
Subject: What are the "safe" parameters for shop humidity?
> 
> Dear List,
>      I seem to be building a new shop in this old
> textile mill ( where those pneumatic-cloth making
> machines are still in my way, by the way !!! ).
>     It is a tiny ( 60,000 sq ft. ) brick structure
> with a concrete floor and 15' ceilings, and I am
> concerned about humidity.
>     I do have a HUGE quantity of 1/4 inch thick, 4
> foot wide rubber conveyor-belting to lay down on the
> floor, but I am still concerned with transpiration
> through the walls. I know that 42% RH is considered
> ideal, but what are the parameters of what could be
> considered "safe".
>     ( i.e., what I shouldn't "sweat" over. )
>      Opinions???
>      Requestfully,
>      Gordon