Zero percent humidity

[Isaac sur Noos]

Chris, that's fun,
 I have a model "pro" with an external sensor from the same brand
(HANNA), and a little one like the one you picture (but with a memory
and thermometer function) . The "pro" model is more precise, but
nowadays, the accuracy is said to be kept for one year, then the
instrument may be regulated again ( BTW these 2 seem to be are made in
China  :<(.)

I don't know where is the problem, but the cheap hygrometer all seem
to be accurate in the "medium" range, when it comes to extremes, they
give really less precise information (may be depending of the state of
the batteries) Some also are faster than others, to have a very low
reading can take as long as 5-10 minutes.

Nowadays the information on your hygrometer allow a range of measure
from 10 to 90% only, does not mean it can't display 0%, it is easy to
get near 0% H.R in fact with a very cold air, as this is the point
where water turns to ice (there is a certain difference between the 2
but I can't explain it).

Here in Paris a lot of modern buildings have their humidification
systems that have been turned off because the system employed ("air
washing")was distributing illness and bacteria in the buildings (10-15
years ago we experienced a heavy "Legionellose" episode). Now more
clean humidification systems are available, but in most cases no one
cared to ask for the systems to be installed, I even wonder if in the
air quality norms there is a point about H.R.

I was suspecting that lack of humidification for sometime, so every
time I can talk with the people that repair HVAC in institutional
buildings I ask them about, and apparently I was right.

Nowadays we are in a moderate climate, and even during winter some
humidity remains in the walls and the ground the low cases are around
20 % HR I never have measured a lower state in rooms and buildings.

Not to say pianos don't appreciate Damp Chasers !

Best Regards.

Isaac OLEG


> -----Message d'origine-----
> De : pianotech-bounces@ptg.org
> [mailto:pianotech-bounces@ptg.org]De la
> part de Chris Gregg
> Envoye : mercredi 7 janvier 2004 06:20
> A : Pianotech
> Objet : Zero percent humidity
>
>
>
>
> I have a fairly accurate hygrometer.  I bought it from a scientific
> instrument supply company.  I have been using it for the
> past year and have
> been delighted with the performance. A description of it
> can be seen at
> http://www.hannacan.com/fiches_techniques/HI98601.pdf
> Up here in the far North we have just been going through a
> cold spell  with
> an mass of Arctic air over us.  I knew it was dry in some
> homes, have had
> the humidity down to 5 to 8% at times, however this is
> nothing compared to
> some public buildings that have music schools in them.  I
> was in one
> yesterday that recorded 2.7 percent in one room and this
> evening I was in a
> building that actually took the gauge down to 0% for a few
> moments.  I did
> not know this was possible, however I guess it is.  It must
> be like sitting
> right inside the furnace.  Some of the local piano salesmen
> tell me they
> sometimes hear things go crack on the showroom floor.  I
> wonder why?  We
> even have laminated boards that crack in this part of the
> world.  Keeps us
> busy though.  Install lots of Dampp Chasers around this
> time of year.
>
> Chris
>
>
> _______________________________________________
> pianotech list info: https://www.moypiano.com/resources/#archives
>