Hi Randye:

Humidity levels are relative to temperature.  You did not indicate the  
temperatures involved.  The thing to do is have good instruments to  
watch and measure both temperature and humidity readings  
periodically.  You will notice major changes with the four seasons of  
the year and also perhaps with the number of people in the room.

The low humidity is good for both media and equipment as it retards  
various negative unwanted chemical reactions and also keeps down the  
risk of the growth of mold and fungus.   Humidity of 20% to 30% is  
excellent for media and is typically recommended in various well  
established long term storage standards for many chemical reasons.

Your note did not mention heating and air conditioning issues.  Air  
Conditioning dehumidifies and removes moisture when it drops the air  
temperature.  Heating is of different kinds.  If the heating is by  
radiators, or electric coil heaters, these tend to dry out the air and  
drop the humidity.   Heating by forced air systems may or may not have  
a humidifier in the furnace room which can be adjusted to add humidity  
moisture as desired and specified to the warm air circulated through  
the system.   As I do not know any of these heating and cooling issues  
in detail, I simply make the above general comments.

Evidently the staff or others are feeling some discomfort at the lower  
humidity levels, with perhaps dry throats, etc.
If the humidity is raised for people, then this is not good for the  
media and equipment, so there is a bit of a conflict on the humidity  
issue.  The best thing is to leave the room humidity as it is, not add  
a humidifier, and for those who feel dried out to drink some water,  
soft drinks, etc. occasionally to re-hydrate themselves.   Most places  
have humidity levels that are way too high and thus have lots of high  
humidity related media and equipment problems. They have to use  
dehumidifiers to get rid of the high moisture.   So consider yourself  
fortunate not to have the high humidity problem.  If people will drink  
more water based liquids, then everyone and everything should be happy.

Also another issue not mentioned that may be a factor in staff  
discomfort is Oxygen levels and Carbon Dioxide levels.  If the
room is tightly sealed and does not get fresh air circulation  
occasionally,  and there are a lot of people in the room, they can  
consume a fair amount of Oxygen, just from ordinary breathing.  The  
Carbon Dioxide levels will also then go up, and this can make people  
feel stuffy, drowsy,  or uncomfortable.  It might be a good thing to  
look into the fresh air and Oxygen level issue just to be sure things  
are OK on this front, especially when a lot of people have been in the  
room for a long time.  Are doors closed or open?

Hope this helps.   Charlie Richardson

On Dec 4, 2008, at 11:39 AM, Jones, Randye wrote:

> Good day, all!
> We are considering installing a humidifier to address the low  
> humidity (21-22% at present) in our library's Listening Room.   
> However, I'm very concerned about whether it would adversely affect  
> the audio and video equipment and/or the video and audio collections  
> housed here.
> One thing we are considering is placing the humidifier in the outer  
> public area so that the steam generated would be less likely to  
> directly contact the equipment or collections.
> What is your experience?  It has been suggested that the higher  
> humidity would not only benefit the staff but the materials in the  
> room.
> Thanks for any input you can provide.
> Regards,
> Randye
> -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
>    |      | Randye Jones
>    | )    | Listening Room Supervisor
>  / |      | Grinnell College Libraries, Grinnell, IA 50112
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>    |      | Phone: 641-269-3365 FAX: 641-269-4283