Here comes the cold!

Posted by: RonTuner

Here comes the cold! - 01/22/13 09:01 AM

And with it, the indoor humidity is dropping!



This is the lowest I've seen this year - how about you?
Posted by: Jerry Groot RPT

Re: Here comes the cold! - 01/22/13 09:11 AM

I've seen the RH as low as 8 % here last month already. It's BUTT COLD here in Michigan, around 1 degree and lower with the wind chill.
Posted by: RonTuner

Re: Here comes the cold! - 01/22/13 09:26 AM

Around 14% here at school this morning. The weather in Chicago has been so mild the last few years that everyone seems to be treating the cold as something unusual - it IS January after all! Dipped just a bit below zero this morning... Time to pull out the bigger coat and the flannel-lined jeans! Just last week, most indoor humidity was still in the mid to upper 30% range...
Posted by: woodog

Re: Here comes the cold! - 01/22/13 09:45 AM

14°F makes for a brisk bicycle ride into work. (wool, baby!)

It also makes for frozen brake cables... much fun to find that out as you are headed down a hill!

My piano doesn't like the low humidity, that's for sure!

Forrest
Posted by: Emmery

Re: Here comes the cold! - 01/22/13 09:53 AM

5 deg F here in Fort Erie this morning. Outside RH is 56%, inside it is about 27%. Have to feed my DC unit water every week and half now. At this point I convert from both celciaus and fahrenheit to the more appropriate and universally understood $%&@# its cold scale.
Posted by: Eric Gloo

Re: Here comes the cold! - 01/22/13 10:19 AM

Does that thermometer read 79.4 degrees??? If so, that's one of the main reasons the humidity is at 18%.
Posted by: RonTuner

Re: Here comes the cold! - 01/22/13 11:10 AM

Yup, the heat in that room was crazy! It was still 20% downstairs in another studio where the temp was 61 degrees...
Posted by: Mark Cerisano, RPT

Re: Here comes the cold! - 01/22/13 11:46 AM

RH is an interesting thing that not everyone understands. I, myself, only really understood it about ten years ago, after being a tuner for three years and having a degree in engineering. Another tuner explained to me.

It is a percentage that describes the Actual Water Content in the air (call it AWC), relative to the Total amount of Water that the air is Capable of holding (call it TWC). RH = AWC/TWC

Higher temperature and lower atmospheric pressure increases the total amount of water that the air is capable of holding. (Higher temperature increases TWC, which reduces the fraction AWC/TWC, and therefore reduces RH.)

That is why Eric says the high temperaure reading is contributing to a lower RH reading on the hygrometer.

Cold temperature actually produces high RH (outside that is). As the temperature drops, the total amount of water that the air is capable of holding (if there was excessive water around to be held) decreases. (TWC decreases) And AWC/TWC (RH) actually increases. When the temperature gets really low, the air cannot hold very much moisture at all, we see it all around us as snow; the water has been "squeezed" out of the air. But then we bring the air into our homes and heat it up. So AWC has decreased (condensation) and TWC increases due to higher temperatures, and AWC/TWC (or RH) decreases.

So, for example, keeping a piano in a cold garage (not below 32 deg F, 0 deg C, that can cause swollen wood when the water freezes in the wood fibres) can actually put it in a decent RH environment.

I once left a hygrometer in my car in the summer time. When I came back, it read 44 deg C. (111 deg F) and 42% RH! (TWC was very high due to high temperature, and therefore AWC/TWC was lower than outside.)

There are many more implications to this when considering air conditioning which strips AWC and humidifiers and drafts and cold basements and hot upper floors, etc.

E.g. Air from an air conditioner, immediately leaving the unit, has a very high RH (the air has just been cooled down to 100% RH and lower. That's why there's condensation out the back). Yet, we generally assume an air conditioned home has a lower RH, which in most cases is has, but not right next to the A/C.

100 year old pianos with no soundboard cracks, may have spent many years in poorly heated and drafty homes, which kept the RH from going too low. Today, the efficient homes' insulation allows us to keep the heat up but results in lower RH than an older inefficient home would produce.
Posted by: Emmery

Re: Here comes the cold! - 01/22/13 12:10 PM

Originally Posted By: Mark Cerisano, RPT
RH is an interesting thing that not everyone understands. I, myself, only really understood it about ten years ago, after being a tuner for three years and having a degree in engineering. Another tuner explained to me.

It is a percentage that describes the Actual Water Content in the air (call it AWC), relative to the Total amount of Water that the air is Capable of holding (call it TWC). RH = AWC/TWC

Higher temperature and lower atmospheric pressure increases the total amount of water that the air is capable of holding. (Higher temperature increases TWC, which reduces the fraction AWC/TWC, and therefore reduces RH.)

That is why Eric says the high temperaure reading is contributing to a lower RH reading on the hygrometer.

Cold temperature actually produces high RH (outside that is). As the temperature drops, the total amount of water that the air is capable of holding (if there was excessive water around to be held) decreases. (TWC decreases) And AWC/TWC (RH) actually increases. When the temperature gets really low, the air cannot hold very much moisture at all, we see it all around us as snow; the water has been "squeezed" out of the air. But then we bring the air into our homes and heat it up. So AWC has decreased (condensation) and TWC increases due to higher temperatures, and AWC/TWC (or RH) decreases.

So, for example, keeping a piano in a cold garage (not below 32 deg F, 0 deg C, that can cause swollen wood when the water freezes in the wood fibres) can actually put it in a decent RH environment.

I once left a hygrometer in my car in the summer time. When I came back, it read 44 deg C. (111 deg F) and 42% RH! (TWC was very high due to high temperature, and therefore AWC/TWC was lower than outside.)

There are many more implications to this when considering air conditioning which strips AWC and humidifiers and drafts and cold basements and hot upper floors, etc.

E.g. Air from an air conditioner, immediately leaving the unit, has a very high RH (the air has just been cooled down to 100% RH and lower. That's why there's condensation out the back). Yet, we generally assume an air conditioned home has a lower RH, which in most cases is has, but not right next to the A/C.

100 year old pianos with no soundboard cracks, may have spent many years in poorly heated and drafty homes, which kept the RH from going too low. Today, the efficient homes' insulation allows us to keep the heat up but results in lower RH than an older inefficient home would produce.


You will find that your understanding of what RH is in the above falls far short of reality. Air is not even required for an RH reading , nor does air "hold" water vapour. John Dalton (scientist) concluded that the vapor pressure of water in air is independent of the existence of the air back in 1803. There are numerous conditions that blow simplified, dummied down explanations of RH clear out of the water. Eg. RH can be determined in a non air environment because air is not a requirement for water vapour to be present. Secondly, the common accepted number of 100% RH is mistakenly associated with the transition point/saturation point for water vapour. Again this is not correct wince it applies to the waters' molecule structure over a flat surface. A non flat surface such as a cloud formation will reach saturation at higher levels...typically 101-103%. The reality is that a perfectly smooth container with no abberations and a completely dust/molecule free environment in it can hold water vapour up to even 200-300% concentration before saturation occurs.

Best read this to fully understand what RH truly is, since numerous textbooks and other information sources dummy down the explanation to simple laymens terms which can be torn apart under close scientific scrutiny...

http://www.atmos.umd.edu/~stevenb/vapor/


Posted by: Mark Cerisano, RPT

Re: Here comes the cold! - 01/22/13 12:26 PM

Thanks for that Emmery. I will certainly read it. But my interest is in practical applications of RH, in which my reasoning still applies. I'm not writing a thesis here, just providing practical advice that works in the real world that I live in, not space.
Posted by: Emmery

Re: Here comes the cold! - 01/22/13 02:34 PM

I'm sorry Mark, but a definition of an extremely precise scientific measurement is exactly that, not a simplified explanation related to your own inferance of its specific use.

To put it in a nutshell, you state "RH is an interesting thing that not everyone understands. I, myself, only really understood it about ten years ago...It is a percentage that describes the Actual Water Content in the air (call it AWC), relative to the Total amount of Water that the air is Capable of holding (call it TWC)."

If your were talking about the "relative humidity of an air-water mixture" you are reasonably correct in your understanding. I simply pointed out that it is neither correct, nor a full understanding of it, if you are talking about "Relative Humidity". As for your explanation of its practicality, perhaps you meant "widespread common layman usage". RH measurements have been done practically on all gaseous containments of water vapour, including a vacume.

Would somebody have a reasonably good understanding of what "speed" is if I told them that its the velocity of an object measured by a speedometer? They could immediatly conclude that sound and light have no speed by that definition.
Posted by: Ralph

Re: Here comes the cold! - 01/22/13 03:02 PM

Well I don't know about this RH business too well, but I know it's freaking cold. I was in Chicago on Sunday on a lay over coming home to Delaware from vacationing in Hawaii for 2 weeks. What a shock coming off the plane at 5AM on Sunday in Chicago. 10 degrees and I hear Monday was colder. Ron I feel your pain.
Posted by: pianolive

Re: Here comes the cold! - 01/22/13 03:07 PM

http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/relhum.html
Posted by: Mark Cerisano, RPT

Re: Here comes the cold! - 01/22/13 03:44 PM

Emmery, your understanding of RH obviously is more in depth than mine. But I am working in an air water mixture and my limited knowledge has served me well. My perspective is as a teacher; one whose mandate it is to help other people who want to learn piano tuning, be able to learn it as quickly as possible (quicker than I did, aanyway) and with a reasonable level of proficiency.

This explanation of RH has helped many of my students grasp the concept better and also helped me to make decisions regarding actual real-world piano experience, with expected outcomes.

Is it perfect? Is it an absolute definition of the entire elemental relationship of the individual parts? Of course not. No scientific explanation of anything is, or else science is dead.

What I deal with as a teacher and technician is cold, hard, factual reality; the reality that helps me service pianos and students. As for the advanced knowledge you refer to, I wasn't blessed with the requisite mental capacity that you obviously have, nor the time. As for being cold, I figure this RH scientific discussion has gotten cold enough. I say let's bury it and get back to the weather.

-10 deg C. (14 deg. F) in PEI. No wind, thank God. We had our deep freeze last week. Working at the university where temperature changes as I walk from one room to the next, yikes!
Posted by: accordeur

Re: Here comes the cold! - 01/22/13 04:36 PM

In the minus 20's celcius here and for the next dew days. Down to the minus 30s with the windchill. Brrrrr.
Posted by: Ralph

Re: Here comes the cold! - 01/22/13 05:09 PM

If dew point is when the air temp drops to a point where it exceeds 100% RH, what is supersaturated air?
Posted by: rysowers

Re: Here comes the cold! - 01/22/13 05:38 PM

Quote:
What I deal with as a teacher and technician is cold, hard, factual reality; the reality that helps me service pianos and students. As for the advanced knowledge you refer to, I wasn't blessed with the requisite mental capacity that you obviously have, nor the time. As for being cold, I figure this RH scientific discussion has gotten cold enough. I say let's bury it and get back to the weather.


Another cold, hard, factual aspect of reality, is that people often get annoyed when others try to give them a lesson when they haven't asked for it. smile

Your tone on the forum comes across (to me, at least) as a little condescending and opportunistic. I'm glad you enjoy teaching, but its good to know when to turn it off, or tone it down. That being said, you have a lot of good things to say and contribute.
Posted by: Mark Cerisano, RPT

Re: Here comes the cold! - 01/22/13 08:52 PM

Originally Posted By: rysowers
Quote:
What I deal with as a teacher and technician is cold, hard, factual reality; the reality that helps me service pianos and students. As for the advanced knowledge you refer to, I wasn't blessed with the requisite mental capacity that you obviously have, nor the time. As for being cold, I figure this RH scientific discussion has gotten cold enough. I say let's bury it and get back to the weather.


Another cold, hard, factual aspect of reality, is that people often get annoyed when others try to give them a lesson when they haven't asked for it. smile

Your tone on the forum comes across (to me, at least) as a little condescending and opportunistic. I'm glad you enjoy teaching, but its good to know when to turn it off, or tone it down. That being said, you have a lot of good things to say and contribute.


Another cold hard fact is that people don't like being told what to do. I'm here to educate. If you like my posts great. If not, stop reading them.
Posted by: Mark Cerisano, RPT

Re: Here comes the cold! - 01/22/13 09:09 PM

After rereading my last post, I reaize it sounds obnoxious. But maybe if you understand that my posts are written with the beginning technician or student in mind, maybe you won't be so offended.
Posted by: Emmery

Re: Here comes the cold! - 01/22/13 09:38 PM

"Another cold, hard, factual aspect of reality, is that people often get annoyed when others try to give them a lesson when they haven't asked for it."

...Especially if the lesson is incomplete, factually wrong, or coming from a tutor that knows less on the subject than they believe they do, and then dismisses the "extra" correct knowledge as inpractical or not of interest. Yeah, type A personalities will cringe from that.
Posted by: RestorerPhil

Re: Here comes the cold! - 01/22/13 10:15 PM

Every time I tell someone who talks about wanting to "keep the heat on for the piano," that it is relative humidity which matters most, I get a blank look. Got that same look from a guy with a doctorate in music just last week.

You would think there would'a been a course!?
frown wow
Posted by: accordeur

Re: Here comes the cold! - 01/22/13 11:01 PM

Mr. Cerisano,

I have to agree with Ryan. Even though you seem to have knowledge to share, your pompous teacher attitude tends to get ...

I don't know, and I am certainly not here to prove you wrong.

I am here, as a piano technician to share some of my experience, be able to ask questions, and hopefully have answers. It has been a success in my book.

Over the years on this forum, I have learnt a bunch of techniques and procedures. Some quite innovative, CA glue, teflon powder, protek, spurlock's jigs and procedures to name but a few. Del's posts are priceless. Just recently acrylic repair of ivory. A great resource.

And just good common sense.

We get to know the members and respect them for their contributions.

Having said that, I owe this forum, I have not contributed as much as I have received.

This forum is called the piano technician's forum.

I don't mind newbies or even DIYers, as long as they are earnest and inquisitive.

All the best.
Posted by: Mark Cerisano, RPT

Re: Here comes the cold! - 01/22/13 11:06 PM

Originally Posted By: Emmery
"Another cold, hard, factual aspect of reality, is that people often get annoyed when others try to give them a lesson when they haven't asked for it."

...Especially if the lesson is incomplete, factually wrong, or coming from a tutor that knows less on the subject than they believe they do, and then dismisses the "extra" correct knowledge as inpractical or not of interest. Yeah, type A personalities will cringe from that.


Practical performance is full of examples of approximations of complete scientific fact because the accurate prediction is impractical, too complicated and not useful. As well, the situation has its share of brilliant minds who continue to feel unrecognized and not respected because it appears no one is listening to them. They continue to exist in their own world where they are right and everybody else is wrong.

Perhaps the tech who couldn't explain to the doctor of music about RH would appreciate the more complete explanation of RH. Maybe he could explain the molecular situation with dust and smooth surfaces and super saturated 200 % RH. That should get him to realize the error of his ways.
Posted by: Olek

Re: Here comes the cold! - 01/22/13 11:23 PM

What I understand is that RH percent number says how much moisture is in the air (or any gas if you want) before saturation.

So temperature and (athmospheric) pressure level influence the result.

I dont se why it may exprim the amount of water, only when making the reverse computation you obtain the weight of water in the gaz.

The "on a flat surface" aspect can probably be left aside for common understanding, but I dont get the explanations from Mark probably for the way they are presented.

The digital hr use the surface tension of the water in air to determine tge HR ? Is temperature tested by the Hygrostat ? I guess no it may only use conductivity to check a certain amount of water.

Then I question the error margin , unless the data are obtained with the help of thermometer often inclueded in the best hygrometers.
Posted by: Mark Cerisano, RPT

Re: Here comes the cold! - 01/22/13 11:25 PM

Originally Posted By: accordeur
Mr. Cerisano,

I have to agree with Ryan. Even though you seem to have knowledge to share, your pompous teacher attitude tends to get ...

I don't know, and I am certainly not here to prove you wrong.

I am here, as a piano technician to share some of my experience, be able to ask questions, and hopefully have answers. It has been a success in my book.

Over the years on this forum, I have learnt a bunch of techniques and procedures. Some quite innovative, CA glue, teflon powder, protek, spurlock's jigs and procedures to name but a few. Del's posts are priceless. Just recently acrylic repair of ivory. A great resource.

And just good common sense.

We get to know the members and respect them for their contributions.

Having said that, I owe this forum, I have not contributed as much as I have received.

This forum is called the piano technician's forum.

I don't mind newbies or even DIYers, as long as they are earnest and inquisitive.

All the best.


That is so generous of you not to mind the DIYers. I can see I am going to have to stay in this forum and continue to be a voice for those. Of course, I would be more than happy to spend my time on the "Learn to Tune Pianos" forum, but there isn't one. So I guess we are all going to have to learn to get along. I think that's how Frank put it, wasn't it? Getting along would be so nice, not at all like name calling or put downs, would it? And yet, I don't seem to remember ever throwing the first stone in these forums. How strange. Why is that? People, please, remember why I am posting. I have already mentioned it. If you find my tone offensive, stop reading. The posts are not for you. You are like an experienced battle soldier who goes into an army cadet meeting and cringes at the toy rifles. I'll say it again, my posts are not for experienced techs who are offended by approach. My perspective is and always has been that piano tuning is a craft that any musical person can learn to do, with the right teacher. If I'm obnoxious and arrogant, my students made me that way. Strangely enough, my temper in front of a class is much more patient than you may gather from some of my defensive posts. You guys just bring out the best in me I guess. But, that's the beauty of social media, as I am starting to see. I know there are hundreds of techs etc just watching these proceedings saying "there but for the grace of God, go I"

So, post away. I may take my own advice and just stop reading them.
Posted by: rysowers

Re: Here comes the cold! - 01/23/13 12:06 AM

Originally Posted By: Mark Cerisano, RPT
After rereading my last post, I reaize it sounds obnoxious. But maybe if you understand that my posts are written with the beginning technician or student in mind, maybe you won't be so offended.


Mark - I'm sorry if you think I was offended - mildly annoyed? Perhaps. Offended - no. I also went out of my way to compliment you. I was (perhaps ineffectively) suggesting that taking a less professorial role here may make your ideas better received.

Posted by: RestorerPhil

Re: Here comes the cold! - 01/23/13 12:21 AM



I am one who has realized that most doctors in music are doctors of music, and are not scientists. Most seem to think that, "In the winter, a warm room is good, and a cold room is bad, and it is that simple." Any explanation of why that is not necessarily the case often generated a blank look which revealed incredulity on their part. That is why I joked that one would think that doctors of music should have to take a course which at least explains the issues of RH for the sake of pianos, woodwinds, and other instruments which can suffer if the moisture content of the wood in them is altered too much or is altered too quickly.

There was a time when I would get into an explanation. The "blank look" has become so ubiquitous that I suppose I now anticipate it, choosing now to save my breath and foregoing the explanation to them, and get back to paying work. I can always give them a Dampp Chaser brochure later, and maybe get into a discussion with pictures to help get the point across.

It was a JOKE:
"You would think there would'a been a course!?"
frown wow
Posted by: Olek

Re: Here comes the cold! - 01/23/13 01:06 AM

Give them a price for soundboard repair and a moisture table.

Because, no matter the conditions, if the piano is in trouble they wil think for a time there is some obscure relation with the tuner .

Before Dampp Chaser, ask where is the hygrometer and how is the moisture there. Then it is THEIR responsability to get interest in the matter.

Hygrometers where in all places with pianos yet in 1930. An Iphone is something else (explain them)

In the end we have to be offensive if we want to keep tge customer...as a technician or rebuilder.

If not uou could only sell them pianos, the adequate moisture conditions are part of he customer dues so it is not your trouble in that case.

Posted by: RestorerPhil

Re: Here comes the cold! - 01/23/13 06:40 AM

How cold is it?

Pert' near cold!

How dry is it?

Bone dry!

What's in your piano?

grin
Posted by: Olek

Re: Here comes the cold! - 01/23/13 07:36 AM

Piano is too dry

Must be cracking the soundboard

Moisture desire


St Isaac "Kamin" the young - first age of dry MMXIII
Posted by: woodfab

Re: Here comes the cold! - 01/23/13 08:51 AM

Over the last couple of weeks sitting in my van is a 5' grand with a mint soundboard.
The temperature has gone from 60F down to 7F I haven't measured the RH but we've had rain and snow.
I haven't had time to move the piano onto my shop.
I'm hope that crossing my fingers will help.
Posted by: Silverwood Pianos

Re: Here comes the cold! - 01/23/13 11:34 AM


Yesterday in Winnipeg, Canada the daily high was -21 Celsius (-6 F). The day previous was -40 and postal workers were ordered not to deliver.
Posted by: woodfab

Re: Here comes the cold! - 01/23/13 04:44 PM

That's pretty cold.
I work for a small company in their wood shop. They don't like paying for heat so I'm not allowed to turn it on.
The shop gets quite cold sometimes around 40F.
Don't tell my boss but if I know he won't be around I turn it on.
Posted by: Emmery

Re: Here comes the cold! - 01/23/13 07:06 PM

Posted by: Mark R.

Re: Here comes the cold! - 01/24/13 05:17 AM

Just for harmony and counterpoint:

Here in the southern subtropics (two hours' drive south of the Tropic of Crappycorn), the mercury topped out at 32°C (90 F) yesterday, and we're expecting 35°C (95 F) today.

Can one of you send me some snow, please?