Temperature & Humidity Control

[jbs]

For tuning stability and to prevent physical deterioration of grand pianos Steinways recommend the room where the piano is kept should be kept at 20 degrees centigrade and 45-70% humidity. Bosendorfers advise a temperature of 20 degrees centigrade and humidity range 40-65% , ideally 50-55%. They also say that the whole of the room in which the piano is located should be kept within these parameters not just the local area around the piano. That last sentence would seem to rule out the Damp Chaser system which will control only the air immediately below the sound board.
Positioning the piano out of reach of direct sunlight, away from external walls, drafts and central heating radiators will help but will not alone achieve the recommendations.
Both firms suggest the Venta range of humidifiers which are made in Germany. But these have to be topped up with water every few days so if you go away for a period leaving the piano by itself they will stop working when the water runs out.
An well insulated room offers some protection against extremes of temperature but in most homes UK homes the heating is switched off at night and room temperatures may fall to 10 degrees C. or lower in winter. Rising energy costs and the importance of low CO2 emissions are other factors.

-Can anyone supply me with references to the published scientific studies in to this matter so that I can assess the degree of risk to my piano when its environment is not kept within these parameters ?
-Does anyone know of a company that has developed some modern technology that would allow me to monitor conditions in my piano's room, via the internet, while I am away?
-Does anyone have details of a humidification device that will have a sufficient reservoir of water to function automatically, unattended for periods up to three months, in a room of say 100 cubic metres, (3000 cubic feet) in volume, assuming a temperature range of 17-23 deg. C. ?

[Barrie Heaton]

Don't some of the Venta one have a Reservoir of 3 gallons

Don't some of the Venta one have a Reservoir of 3 gallons

Dampchaser probably has the most info on room humidity

if you are away for 3 months would it not be a good idea to get some to pop in every week to top up if it’s the summer months would it not be too much humidity be the problem


Barrie

[athomik]

The worst problem is sudden swings in temperature/humidity or long term exposure to extremes of temperature/humidity - dryness. As long as you can find a way of keeping the room in reasonably comfortable conditions, the piano should be OK. If there are periods when you can't control conditions or if the room is proving to be a problem, something like a Damp Chaser system can be useful, even if it does involve a bit of regular maintenance.

The worst piano I saw was a Disklavier, which was only a few years old. It was kept in a hall at the University of Surrey, which was airconditioned 24 hours a day. It was completely dried out,they replaced it the next year. - And there was a Steinway concert grand in the corner which must have been in the same condition.

[jbs]

Thank you both for your replies.
I have been in touch with Venta. They have not been specific about the water replenishment interval if I were to buy the model appropriate for the size of my piano room. To be fair to them this will vary according to the room structure, furnishings, heating and prevailing weather conditions outside. However, an approximate range would have been useful.
I have discovered devices that will relay temperature and humidity measurements wirelessly to integrate with home heating systems and relay their measurements over the internet. The Venta systems do not however provide any means of connection with this sort of monitor and remote control.
The major piano manufacturers must surely have dome some modern research on how their pianos are affected by temperature and humidity changes, where do I find their results ? Or are they unavailable because such information is a closely guarded commercially sensitive secret? Surely the profession of piano tuners has access to this?
Athomik - your anecdote surely means that the air conditioning in the University of Surrey was set to provide the wrong conditions in that room, was anything done about it?

This is the 21st century but this isn't rocket science ! Why are manufacturers so quiet about it? Is it because if people looked after their instruments properly they would loose sales on replacements? If I buy a car I get lots of numerical data for comparison purposes between models e.g miles per gallon etc.
I don't think the piano tuners need fear a loss of business due to less frequent need for tuning, surely if they promoted proper care of their customers pianos, those customers would become more discerning about slight departures from being in perfect tune and call them back just as often or may be more frequently.

So may I appeal again to anyone who follows this forum, WHERE CAN I GET MORE SCIENTIFIC FACTS PLEASE?

[Barrie Heaton]

This is the 21st century but this isn't rocket science ! Why are manufacturers so quiet about it? Is it because if people looked after their instruments properly they would loose sales on replacements?

Hardly as pianos tend to last 50 year s +

If I buy a car I get lots of numerical data for comparison purposes between models e.g miles per gallon etc.
I don't think the piano tuners need fear a loss of business due to less frequent need for tuning, surely if they promoted proper care of their customers pianos, those customers would become more discerning about slight departures from being in perfect tune and call them back just as often or may be more frequently.

The manufacturers manly rely on you having your piano tuned twice a year use to be 4 times a year However, because of recent changes in home heating and insulation over the last 30 years manufacturers have to state a recommended temp and humid as a guideline. but it is still your tuner who is the best to advise on the pianos survival on your room

So may I appeal again to anyone who follows this forum, WHERE CAN I GET MORE SCIENTIFIC FACTS PLEASE?

For the last 300 years the manufacturers and tuners have kept the great unwashed in the dark about why we do this and that it been a closed profession for the last 300 years. In the last 25 years we have had the internet so it is coming a little more open, but the info you seek is not in the public domain like most thing to do with pianos




Barrie

[Withindale]

WHERE CAN I GET MORE SCIENTIFIC FACTS PLEASE?

Three suggestions:

1. Contact some larger piano manufacturers but you may find the "company secrets" files contain less than you imagine.
2. Search for the effects of humidity and temperature on the various types of wood and on antique furniture. There are some interesting facts and figures on the internet.
3. Compare temperature and humidity swings in your area with the extremes found in the USA. That may put things in perspective.

All this will give you an idea of the likely stresses and strains in your piano.

[jbs]

Well, if better attention could be paid to piano room climate control then pianos might surely last more than 50 years.
Thank you Whithindale for your three suggestions.
And Barrie, I am pleased that you confirm my impression that the specific information is not in the public domain. How do we get it made available to us? I have toured two piano factories of different manufacturers each with an top international reputation, the guide hinted at ongoing research but no more.
In recent years there have been many examples where people have shared their good ideas online and this has led to a level of international cooperation and pooling of ideas and talent with rapid development of a new product to the benefit of everybody.
I LIVE IN HOPE THAT SOMEBODY CAN POST A REFERENCE (or URL) TO A PUBLISHED SCIENTIFIC PAPER.

On a different tack, yes tuners are an important source of advice but where do they get their knowledge about this from ?
Is it mainly hearsay passed on by their teachers?

AGAIN DOES ANYBODY KNOW OF A COMPANY THAT MAKES EQUIPMENT THAT WILL RAISE OR LOWER THE HUMIDITY THROUGHOUT A SINGLE ROOM IN A HOME AUTOMATICALLY WITHIN PRESET LIMITS?

[Barrie Heaton]

On a different tack, yes tuners are an important source of advice but where do they get their knowledge about this from ?
Is it mainly hearsay passed on by their teachers?

Most of the info manufactures get is from tuners, we are the ones who service the pianos, we are the ones who feed back to the shops, who feed to the rep, who in turn feed back to the factory. Some info may get lost translation. Then some information is pasted back to the tuners but that can be conflicting as different manufactures can’t agree on max and min temp never mind humidity, Some endorse life savers some tell us not to use them. Manufactures don’t publish info like that because they don’t want give their competitors that info, but more important not to degrade their products that may suffer worse than the other makes in the same environment. As tuners we know which make and models swings the most in a changing environment and we do disuse it in private news groups and would not normally put that info in the public domain.

Yamaha did a big thing in the mid 00 in the USA “seasoned for destination” this was to say they made pianos for certain climates which is nothing new. However, this was more of an attempt to stop the import of Grey Market pianos into the USA which was harming sales of new pianos. which may have backfired on them as I was told by one US shop it had made sales of new pianos harder as folk was asking was this seasoned for Chicago as the shop down the road are saying that your pianos are cheap because they are seasoned for Europe.

Will you see a scientific paper on the effects of Humidity and heat on wood yes by the timber industry, but not by the piano industry?

Barrie

[chrisw]

I was under the impression that modern pianos are designed to resist the effects of central heating although excess changes of temperature and humidity still need to be avoided. For example is not the wrest plank laminated so that it is less likely to be affected ?

Timber never stops moving across the grain as it either takes up or looses water to the atmosphere. Ambient temperature will affect the take up or loss rate. It will move relative to the conditions the timber was seasoned. Thus if it is seasoned in the traditional way, in other words outside with just a canopy over, I imagine its datum temperature could be slightly less than room temperature. I would imagine most timbers are kiln dried but do not know at what temperature. I guess it doesn't matter if kiln dried timber is used to form a laminate since the grains alternate and are perpendicular.

With respect to change in temperature affecting tuning, at least in the short term, I presume this depends on the relative thermal expansion of the frame and strings. Again I would imagine that part of the decision in the choice of materials is to match the coefficients of linear thermal expansion.

As you can tell I am not a piano tuner or restorer, but love playing the piano and am very interested in how it works as both a physicist and amateur cabinet maker. I would welcome any comment which corrects my current understanding.

[Barrie Heaton]

I was under the impression that modern pianos are designed to resist the effects of central heating although excess changes of temperature and humidity still need to be avoided. For example is not the wrest plank laminated so that it is less likely to be affected ?

While laminated wrest planks are less likely to split, they still can be prone to change in humidity, If you put a modem piano in a humid environment, the plank will swell it has nowhere to go, so the fibres around the tuning pin expand then get crushed. If the piano is moved into a normal environment when the piano dries out to where it was the holes for the pins are bigger so tuning pins are not as good this happens with the best of makes

Timber never stops moving across the grain as it either takes up or looses water to the atmosphere. Ambient temperature will affect the take up or loss rate. It will move relative to the conditions the timber was seasoned. Thus if it is seasoned in the traditional way, in other words outside with just a canopy over, I imagine its datum temperature could be slightly less than room temperature. I would imagine most timbers are kiln dried but do not know at what temperature. I guess it doesn't matter if kiln dried timber is used to form a laminate since the grains alternate and are perpendicular.

Soundboards are very prone to small changes in humidity even laminated boards will move as timber is timer a lot depends on how well they are sealed However, modem coatings are too rigid and tend to crack over time letting in humidity some soundboard were coated with polyester back in the 70s and the soundboards turned into crazy paving due to movement so you can't win you just need to control the environment if you don’t want your piano tuned 4 times a year

Barrie

[vernon]

An interesting point is that all piano bellys are varnished overall to xcluse moisture.
String instruments are only varnished on the exterior. The inside is raw

[jbs]

Hello chrisw
Good to have a scientist join this discussion!
It really is about time the controversy about the DampChaser system is resolved.We will always need the services of tuners and technicians not just for tuning but voicing and regulation. I am aware that some manufacturers have adopted other materials (I think carbon fibre) in to their actions and even the sound boards .e.g Steingraeber-Phoenix & Kawai, I wonder if this will be the future?
Meanwhile Steinway, Fazioli, Bosendorfer etc continue to use traditional materials.

WE NEED SOMEONE WITH ONLINE ACCESS TO A UNIVERSITY LIBRARY, IS ANYONE OUT THERE WHO HAS THIS?

Alas since retirement I no longer have such access myself but I too have a hobby of amateur cabinet making and am a keen pianist.

[chrisw]

Since posting my reply I had a look at an interesting web site called "The piano deconstructed" (http://www.christophersmit.com). Also found an article on seasoning of violin wood (http://www.rocheviloins.com/html/season ... _wood.html) and on piano soundboards (http://www.pianobuilders.com/soundboards.html). Must be hundreds more articles on the web.

If I was constructing a table with a solid wooden top anything more than 12inches wide I would secure it in a way that allows it to expand and contract across the grain and if not I would expect it to crack. Therefore if sound boards are secured all the way around their outer edges it seems to me that you are asking for trouble.

I am sure that manufacturers wish their pianos to give good service over many years and as I said earlier would design them accordingly, appropriate to norms of temperature and humidity inside most peoples sitting or dining rooms. I keep mine in a dining room which is thermostatically controlled to 19/20 degC when the central heating is on. During winter nights the temp falls to 12/13 and in summer it can go up above 25 degC if we are lucky! I don't measure humidity but do keep quite a few plants in the room. My piano tuner visited last week and remarked how well it had kept in tune despite being a year since her last visit. I tend to think my piano has an easy life.

[vernon]

Speaking as an old technician I would say that a few pot plants round your joanna will keep it perfectly healthy. You've got to keep them watered else they will die.
Jam jars in the piano are soon forgotten but not your priceless alopesia plants.

[Barrie Heaton]

If I was constructing a table with a solid wooden top anything more than 12inches wide I would secure it in a way that allows it to expand and contract across the grain and if not I would expect it to crack. Therefore if sound boards are secured all the way around their outer edges it seems to me that you are asking for trouble..

Well that is how it has been done for 300 years. it’s not rigid like a table it has to flex like a drum yet; withstand 1 to 2 tons of downward pressure. If the soundboard shrinks it splits if it expands then you get compression ridges. Both splits and compression ridges are not a problem unless the split starts to vibrate or compressions ridges start to force the belly bars from the soundboard then you have a big problem. In most cases splits tend to forum after you have had compression ridge that have contracted too much

Barrie

[prussell]

I just bought a humidifier on ebay for $40. I have to fill it daily, and it keeps the room between 45-50%. I've noticed the instrument sounds better with higher humidity. It spent the first 6 months in around 35%, which is what the room is normally at without the machine. It started to sound, a certain way (sound always hard to describe). but humidifier keeps it fine.

My teacher has a grand p. and lives by the coast, I notice the natural humidity there is 55%.

[jbs]

More anecdotal evidence, which is fine, thanks, but lets have some science please somebody !

[chrisw]

Jbs,

Table of wood properties attached but not sure if it is easy to read.

Have you seen the Wikipedia article "Wood Drying"

[Withindale]

Also see:

http://www.fpl.fs.fed.us/documnts/fplgt ... ter_04.pdf (and chap 13)

and check Yamaha's website for notes on looking after pianos.

Google lists several humdifiers which can be plumbed into the mains and several smart home systems that will monitor conditions while you are away.

In general you do not have to be a scientist to know that swings in humidity and temperature adversely affect the tuning and performance of pianos and can cause catastrophic damage.

Constant humidity and temperature is the solution.

[jbs]

I have been in touch with the Dampp Chaser company and with their permission post below a reply to 20 questions which I asked. I think the replies, which I have tried to put in bold are very informative.
-----------------------
Your questions are excellent. My answers will go beyond generalities that are listed on our website. Most piano owners are not able to digest and understand the nuances of our system.
That said, I feel our product may not be right for you. Your line of questioning seems to imply an expectation that our product controls relative humidity (RH) with the precision that may not be possible with the variations in piano design and climatic extremes seen in some regions of the world.
RH is much more difficult to control than say temperature, for example. At our factory we calibrate our sensors in an entirely enclosed and isolated chamber that provides only 1 %RH accuracy. The chamber is calibrated to an intermediate standard calibrated to a primary US national standard by Parameter Generation and Control in Black Mountain, NC. In today’s dollars this equipment would likely cost over $100,000 US.
So my suggestion is that you investigate a humidity control system that is retrofitted to your central heating and cooling system. These provide full room humidity control for your piano. I think a good unit can be purchased and installed for under $5,000 US here.
1. " What do you mean by "a cycling action" ? The humidistat activates the dehumidifier then the humidifier in a repeatable cycle usually in a period of 45-90 minutes. However, dramatic changes in room humidity and variations in piano design can affect this cycling.
2. "producing a narrow range of average humidity" - what is the range of humidity produced?
Generally the range is 6 %RH centered somewhere between 43% and 50 %RH.
3."the Humidistat, located less than an inch". Soundboards are up to 6ft long and the humidistat is only on one side of the soundboard. Does the humidistat measure the water content of the air near to it, or directly in the wood of the sound board nearest to it? Air near to it
4. Can you give me references to scientific studies that have measured how the water content in different parts of the wooden soundboard varies in comparison to that in the air near the humidistat? What happens is zones of controlled soundboard equilibrium moisture content are established across the soundboard. Drier zones are near the dehumidifiers, and wetter zones are near the humidifiers. These zones are stable and relatively consistent during system operation, thus providing pitch stability to the piano. We do not have a study that will meet the rigors of your inquiry. You would need, in my estimate, ten identical pianos with systems installed in identical ambient environments to begin to get any statistically reliable data that could be qualified as a scientific study. We are a small business with 20 employees and do not have the resources to conduct such a study at a research university in the United States. We rely on the experience of the world’s premier piano technicians in
order to validate that our systems work. We have been in business for over 65 years and have been producing complete systems for pianos since the 1970s.
5. Where does the water go that is removed by the dehumidifier? No water is removed. RH is lowered by increasing the temperature by 2-3 degrees C.
6. "The piano dehumidifier carries away moisture from the soundboard on air currents". Does the dehumidifier have a fan to blow the moisture away? No. The warm air rises and spreads out across the soundboard. The physical relationship between RH and temperature causes the RH to fall. The absolute amount of moisture in the air is constant, but the capacity of the air to hold water increases. This concept is extremely difficult to explain to most piano owners.
7. What noise level (in dBA) is generated by the fan? Not applicable
8. If the room where the piano is located is unventilated then surely the air surrounding the soundboard will be in equilibrium with that in the rest of the room. If the unventilated room air is too humid how can the moisture content of the air in contact with the soundboard be changed ? My music room volume is 58.4 cu m. (2040.5 cu ft). The system creates a microenvironment within the piano cavity. This can be further isolated by adding an undercover for a grand piano and a backside cover for a vertical piano. Since the controlled environment is warmer than the room environment the controlled air moves through the soundboard to create conditions that stabilize pitch. (See my answer to your question 4.)
9. You say that warm air currents are needed for the dehumidifier to work. What range of temperature does the equipment generate a. in itself? b. in the nearby air? Dehumidifiers have a surface temperature between roughly 52 and 62 degrees C based on model. The humidifier heater bar has a surface temperature of approximately 40 degrees C. The air in the vicinity of a dehumidifier is warmed 2-3 degrees C. For the humidifier this is 1 degree C or less.
10. Doesn't this mean that there will be stress on the soundboard as the underside will be at a different temperature to the upper side ? Soundboards are made from vary porous spruce. Any stress would be minimal due to this pourosity.
11. "the Piano Life Saver's small humidifier requires only one can of water twice a month in most environments." What volume of water in the 'can' are you talking about here? Approximately 2.5 liters
12. Does the device require any other maintenance, e.g. cleaning, de-scaling ? Humidifier pads should be changed annually. A plastic sleeve that reduces scaling on the humidifier heater bar should also be replaced at least annually. We recommend addition of our additive Pad Treatment with each filling of the humidifier. Pad Treatment contains benzalkonium chloride, a mild biocide, which minimizes the formation of mold or mildew on the humidifier pads.
13. What is the acceptable range of 'hardness' of tap water that is suitable to use, e.g in French or American degrees ? I do not know. We recommend that distilled water be used in areas with hard tap water.
14. What would be a typical electricity consumption in kilowatt hours please for a grand piano system in a room of 58.4 cu. m. ? Approximately 0.035 kilowatt hours - This varies somewhat with the model.
15. Bosendorfer's recommend a humidity range of 50-55%, will your system maintain the humidity within this range? No - Different piano manufactures have different recommendations. Our product falls within the general extremes found by combining all reputable manufacturers recommendations.
16. If the room temperature varies between 8 deg. C. and 25 deg. C. depending on the season, weather outside and the time of day, will the device maintain the humidity of the piano within the specified range independent of ambient room temperature? Our system loses its effectiveness below 15 degrees C. Effectiveness is restored when the ambient temperature rises
17. Does it have a control which enables the user to adjust the range of humidity it will generate?
No – We feel the average piano owner could make an adjustment that might result in damage to the piano.
18. Is there a way of connecting the sensors which indicate the water tank level and functioning of the pads to the internet? So that for instance when I am away from home for some weeks I can get a message that a water top up is needed and ask someone to attend to it. We are currently developing a prototype for such an add-on to our product line. We are also surveying piano owners to see what they might be willing to pay for such a device.
19. At today's UK prices what is a typical total annual cost of : PAD water needed, humidifier pads, liner replacement & new plastic clean sleeves ? We cannot fix prices for either piano technicians (installers) or distributors. H.J. Fletcher and Newman is our distributor in the UK. Please see http://www.fletcher-newman.co.uk/.
20. If a grand piano is left unattended for a period of weeks with a DamppChaser attached and in operation, is it best to have the lid fully closed, partly or fully open ? Please give the reasons behind your answer. Lid fully closed – With a grand piano, the more confined the piano cavity is, the better the system functions regardless of whether it is unattended or not.

[Barrie Heaton]

To fill in on the UK bits priced on line are
Piano Life Saver Humidifier Water Treatment £12.80 will last about 18 months
Pads £12.00 will do 4 changes if you cut in half include 2 set of sleeves and bin liner

As to when to change depends where you live and if you use tap water in Lancashire
Southport area 6 months if you leave the for 12 you need the change the plastic sleeve as well
Liverpool area 6 months if you leave the for 12 you need the change the plastic sleeve as well
St Helens Distilled water (do not use tap water )
Wigan area Distilled water (do not use tap water )
Chorley area 6 months if you leave the for 12 you need the change the plastic sleeve as well
Preston area 12 months
Blackburn area 12 months
Burnley and Pendle area 12 months
North Manchester area 6 months if you leave the for 12 you need the change the plastic sleeve as well

The above is what I have found over the years servicing and fitting them

Barrie

[chrisw]

If I was constructing a table with a solid wooden top anything more than 12inches wide I would secure it in a way that allows it to expand and contract across the grain and if not I would expect it to crack. Therefore if sound boards are secured all the way around their outer edges it seems to me that you are asking for trouble..

Well that is how it has been done for 300 years. it’s not rigid like a table it has to flex like a drum yet; withstand 1 to 2 tons of downward pressure. If the soundboard shrinks it splits if it expands then you get compression ridges. Both splits and compression ridges are not a problem unless the split starts to vibrate or compressions ridges start to force the belly bars from the soundboard then you have a big problem. In most cases splits tend to forum after you have had compression ridge that have contracted too much

Barrie

Hello Barrie,
Its good to see the forum back in business. I don't know when it first became available again because the desktop icon on my computer continued to say "shutdown for maintenance" until I clicked on it a few days ago.

Going back to this old thread it occurred to me some while ago that if sound boards are created from timber which is radial cut they would be much less prone to cracking if and when they shrink. Do you know if the piano industry insisted on radial cutting of sound board material or is this something only done for top notch pianos ?

[Barrie Heaton]

if ou men quarter sawn, Then yes they are but all timber moves and with soundboards ou need them to move. The problem is when a soundboard is in a very damp place you then get compression ridges then when it dries out it split but cracks are normally not the problem unless they buzz.


The forum has only been back up for few days we are using new software to run it nd Https still updating the rest of the site and some work is needed on the form

Barrie