[CAUT] Humidity Question

[Michael Magness]

On Feb 8, 2008 4:29 PM, Jeff Tanner <jtanner at mozart.sc.edu> wrote:

> Hi all, We've had a humidity "spike" in our recital hall the last week or
> 10 days.  Every one is screaming that the keys are clammy, fiddle
> fingerboards are clammy and bowhair "skids rather than grabbing the
> strings".  Yeah, yeah, yeah, the pitch of the piano jumped a few cents over
> last weekend, but nothing is screaming high humidity to me.
>
> The "spike"?  We were up to a whopping 55% at one point, which by August
> standards would be a kiln.  But we'd been running in the upper 30% to low
> 40% range fairly consistently until this "spike".
>
> Question is, why is it faculty and students seem to notice condensation on
> the keys if it gets over 48% in February, but if it's 75% in a studio in
> July, nobody mentions it?
>
> I understand walking out of a much cooler, drier hallway into the recital
> hall, which has humidification/dehumidification that is actually working,
> there is a noticeable difference in the feel of the air.  But why is there a
> difference in condensation, or why is there a perception of clamminess now
> and not in August?
>
> Thanks,
> Jeff
>
>
>  Jeff Tanner, RPT
> University of South Carolina
>
>
>
>
Hi Jeff,

Leave it to us northern boys to explain. It's the combination of the
humidity and the cool winter air that causes the condensation, the heat
isn't running enough to dry it out so as the room cools with a higher
humidity content the RH condenses on the non-porous surfaces making them
feel clammy. If it sustains for a long enough period you will begin to
notice a fresh coat of rust on tuning pins and strings from same.
In this area we have two types of AC in summer, the standard type that
de-humidifies as it cools and the large commercial types in big buildings
called chilled water type that (simplified) uses a  fan blowing across pipes
that have cool ground water pumped through them. It cools the air
but doesn't dehumidify and it feels "colder" when you walk in because it is
cold "wet" air. The hard surfaces feel clammy in those buildings too. Same
principle different time of year.
<g>
Mike
-- 
We have enough youth, how about a fountain of SMART?
Michael Magness
Magness Piano Service
608-786-4404
www.IFixPianos.com
email mike at ifixpianos.com
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