Re: Humidity ranges?

[Richard Parker <richard () electrophobia com>]

For a datacenter with a single controlled area the ideal range for relative
humidity (RH) is in the neighborhood of 35% to 50%.

Here are some data points:

  1)  Static electricity is minimized when RH is at or above 35%.

  2)  RH below 25% can cause embrittlement of hygroscopic materials
      such as paper.

  3)  RH above 65% can cause mold growth and metal corrosion.

  4)  Humans are most comfortable when the RH is between 20% and 60%.

  5)  RH above 50% in cold weather can cause condensation inside of
      outer walls (or on equipment itself if the facility has an
      external door or window that opens directly into the controlled
      area).  

Sean Donelan wrote an informative post on a related subject a few year back:

  <http://www.cctec.com/maillists/nanog/historical/9810/msg00276.html>

-Richard