Humidity Question/Answer

[DAMPPCHASR]

This answer was posted about the time posts began to disappear from the
list so I'm posting it again for the benefit of those interested.

Happy Holidays
from everyone at
Dampp-Chaser!

Karen Rives


> Jonathan,

Dampp-Chaser Electronics Corp. has a rather significant research facility
with state of the art instrumentation.  We are constantly running tests on
one or more of the pianos in this facility.  We do this in an effort to
upgrade our product;  to make it more effective and to make it easier for
technicians to work with,  We are constantly comparing current trial trial
results obtained ober the past 8 years with out base line product,  the
5PS and the G5PS systems.  We have run trials with the 5PS and the G5PS so
often with essentially the same results,  there is absolutely no question
that what we are obtaining is accurate.

What we are trying to produce is a consistent moisture content.  In our
trials, we measure this at 6 locations on the front (or top) and back (or
bottom) of the soundboard.  We measure this at other points as well but
for this discussion,  what we do with the soundboard will suffice.  I
should add that we always measure the moisture content in a control
section of soundboard located outside of the piano as well.  This control
was cut from the same piece of relatively new soundboard material that we
use inside the piano.

In brief explanation, the results we have obtained many times over run as
follows after establishing equillibrium:

Ambient Conditions	24%RH 75 degrees F

			CONTROL BLOCK		AVERAGE 6 POINTS IN
							SOUNDBOARD

MOISTURE CONTENT   	less than 5%			    6.8%


Ambient Conditions	72%RH 75 degrees F


			CONTROL BLOCK		AVERAGE 6 POINTS IN
							SOUNDBOARD

MOISTURE CONTENT 	10.8%				8.6%


You can see from this ther is a 1.8% moisture content swing in the piano
with a standard humidity control system while the swing in the control
block is very close to 6%.

While the 1.8% is a significant improvement over the almost 6%, it is our
quest to reduce this even further and it is in this light you now have the
higher powered dehumidifiers and the cover for the backside vertical.
The Ultra vertical system combines these two features with the standard
humidifier.  It might be of interest to you to learn that recent results
(obtained with a now concept that we haven't talked about yet because
additional testing is required) indicates we can push the 6.8
% up to 7.8% during humidification.  This would then have a swing of only
..8%

Since you have asked for feedback let me make a couple of specific
comments.

The small tub in the piano can hold 1 1/2 gallons of water.  When called
for by the humidistat, it constantly gives off moisture, each day.  It is
doing this on a continuous basis. It doesn't give off a spurt that moves
away from the piano and doesn't do any good.  It gives off continuously.
It is warm so it rises  and is absorbed by the wood in the piano.  True if
there is a lot of air movement under a grand piano as is likely if hte
piano is located over a hot air duct, the amount of benefit willbe
lessened and perhaps, depinding on hte air flow, negated.

If you could supply the results that you and others obtained in your
research, we could talk about these and I could get a better idea how to
further help you understand humidity control as provided by the
Dampp-Chaser System.

If you will give me your name and address, I'd be happy to send you
graphical presentations of our work.

Bob Mair
Dampp-Chaser Electronics Corp.
Hendersonville, NC