Hi Elwood, Steinway recommends a variation not outside 45% (low) and 50% (high). They also publish a number for temperature--but I do not remember what the (narrow) range is. Hvac can achieve this, at a price. Where I live the air changes per hour is specified at 7, for public buildings. Find out what the number is where you live. Not only will the building be expensive to build--it will also be not cheap to keep such a system running, from a utilities cost point of view (lots of electricity, lots of water). Living with 45% to 50% may require a building design that has a layered approach. Three shells. The outer shell--no attempt is made to control humidity (temperature is controlled), the next shell is controlled some what, and inner shell is museum standard, no holds barred. Whether the school has pockets deep enough to achieve a 5% window in the inner shell is the question. If a concert hall is part of the area to be controlled be aware that often outside air is brought in for cooling, often just before the audience is allowed into the hall. I've personally measured with a psychodyne a difference of 30% over a 15 minute time frame. You can imagine how much the pianos react to that sort of instability. A rule of thumb for 45" uprights (such as the Yamaha P2) is that A4 may vary 4 cents for every 5% change in humidity. I have also measured a Steinway "A" where the humidity control system had been left unplugged for 3 days (this was before bottom covers). When it was plugged in for 12 hours in mid winter the pitch at A4 rose 14 cents. Humidity in the room was a scant 7%. For the difference in the costs of creating a perfect environment for the pianos in the building--and going with what Don Mannino suggested as a "middle range" (45% to 55%)--it would be many thousands of dollars cheaper to control the pianos individually. At 11:29 AM 5/13/2009 -0500, you wrote: > My Interim Chair shared that information with the architects and >they said, “Wow, those are some tight parameters.” >I’ve measured the humidity level in the present Fine Arts Building as >low as 25% in winter and 80% in the summer with the air conditioning on. >Joy! Elwood Rev. Elwood Doss, Jr., M. M. E., RPT Piano >Technician/Technical Director Department of Music 145 Fine Arts Building >University of Tennessee at Martin Martin, TN 38237 Office: 731/881-1852 >Fax: 731/881-7415 Cell: 731/479-4043 No virus found in this >incoming message. Checked by AVG - www.avg.com Version: 8.5.329 / Virus >Database: 270.12.27/2112 - Release Date: 05/13/09 07:04:00 Regards, Don Rose, B.Mus., A.M.U.S., A.MUS., R.P.T. Non calor sed umor est qui nobis incommodat mailto:pianotuna at yahoo.com http://us.geocities.com/drpt1948/ 3004 Grant Rd. REGINA, SK, S4S 5G7 306-539-0716
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