Dear list, I placed a humidity gauge under a piano for 7 days last week. RH on Sunday was 49%, outside temp mid 60's. By Wed and Thurs the outside temp dropped to 30 F and the RH inside the building dropped to 16%. By the following Sunday, the outside temp was 70 F and the RH was 60%. This type of swing in RH within a week has occured 4 times this winter. I contacted ASHRAE RE: HVAC codes lacking minimum RH levels and humidifier requirements. Here is my email (bottom) and the ASHRAE response (top). Mr. Maret, As you note, the building code determines the regulations required for your building. These will be established and enforced by the local authority having jurisdiction (AHJ). It sounds as if your code requires a maximum but no minimum. That being the case the 40-50% RH level desired by piano makers, does not exceed the maximum, does not cross any minimum, and would comply with the requirement. Some applications may require different operating conditions to assist in the function of that space. ASHRAE design guidance recognizes this and recommendations will vary the temperature and humidity optimal for the space. I don’t believe we publish recommendation for your application. The procedures for changing a code requirement (if necessary) will be stipulated by the local AHJ, not ASHRAE. If you deem necessary I might contact them directly on how to proceed. Regards, Steve Hammerling Technical Services Engineer From: itunepiano at aol.com [mailto:itunepiano at aol.com] Sent: Tuesday, January 11, 2011 8:11 PM To: ASHRAE (Internet Email) Subject: Dry air and codes Hello, I'm responsible for tuning pianos in a brand new music building in Orlando Florida. The new HVAC codes require positive air pressure (injection of mass amounts of outside air) and codes set max RH levels between 50% and 60%. The problem is there is no provision for minimum RH levels, nor a provision for installation of humidification equipment. Piano makers require an RH level from 40% to 50%. The summer A/C level per code of 50% -60% is too high (and uncomfortable for humans as well) Due to the infusion of dry outside air and lack of humidifier in the HVAC, I've measured RH below 15% three times this winter. The normal RH is about 50%. The swing in humidity is damaging to the pianos and takes them wildly out of tune. I would be looking for a minimum humidity level imposed by code, and requirement of HVAC humidifiers in school/university/concert halls/ and churches. What would be the procedure to set this in motion, and what road blocks would we need to overcome? Bob Maret -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/caut.php/attachments/20110119/75536951/attachment-0001.htm>
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