I believe some kinds of engineers (ASHRAE? America Society of Heating, Refrigeration, and Airconditioning Engineers?) and some HVAC system people can calculate this for room size spaces/whole buildings. They calculate heating and cooling loads, and figure in local climate conditions, and maybe building structure, insulation, etc. Do you need to humidify and dehumidify? I have seen figures for amounts of silica gel needed to stabilize a storage case (probably in the catalogs selling selica gel, as well as other references). Portable humidifier and dehumidifier sales literature includes output information in various forms. Good luck! Randi Sue Smith Curator D.C. Booth Historic National Fish Hatchery 423 Hatchery Circle Spearfish, SD 57783 605-642-7730 605-642-2336 fax [log in to unmask] Oliver Hirsch <archivalframing@JUN To: [log in to unmask] O.COM> cc: Sent by: Museum Subject: Relative Humidity Question discussion list <[log in to unmask] LSOFT.COM> 11/06/2001 03:51 PM Please respond to Museum discussion list We are involved in an art storage project for a client, and have a question regarding stabilizing the relative humidity of our space. We aim to maintain a RH of 40%, and are writing the List to ask if anyone might be familiar with a formula or a rule-of-thumb that allows one to calculate the size of humidification unit required to stabilize RHat 40-50% in relation to a specified cubic footage? Thank you in advance for any help. Best, Noelle Roberts Hirsch and Associates Fine Arts Services New York ========================================================= Important Subscriber Information: The Museum-L FAQ file is located at http://www.finalchapter.com/museum-l-faq/ . You may obtain detailed information about the listserv commands by sending a one line e-mail message to [log in to unmask] . The body of the message should read "help" (without the quotes). If you decide to leave Museum-L, please send a one line e-mail message to [log in to unmask] . The body of the message should read "Signoff Museum-L" (without the quotes). ========================================================= Important Subscriber Information: The Museum-L FAQ file is located at http://www.finalchapter.com/museum-l-faq/ . You may obtain detailed information about the listserv commands by sending a one line e-mail message to [log in to unmask] . The body of the message should read "help" (without the quotes). If you decide to leave Museum-L, please send a one line e-mail message to [log in to unmask] . The body of the message should read "Signoff Museum-L" (without the quotes).