What's the ideal humidity level for a room full of servers?

Question

What is the ideal humidity level (or range) for a room dedicated to servers?

Answer 1

They say relative humidity should be maintained at a level between 30%-50%

Answer 2

The key here is not to find the ideal humidity and set it at a specific level, but to prevent humidity fluctuations. Most equipment is fine with 5-95% non condensing humidity*.

The key to prevent it from fluctuating, however, is to control it.

When you control it, youhave to define the level.

This brings us full circle, and the correct answer is:

Set the humidity control to consume the least amount of power.

This is done by determining the natural humidity of the room when it's not under control, and averaging it out so the humidity control system doesn't have to exert so much energy maintaining a consistent humidity.

This will also depend on the control system - some systems only humidify, others only de-humidify, and some do both. You may also want to account for human comfort if the server room is also a frequent workspace (hopefully it isn't).

*There have been studies on tin whisker growth in many environments, and so far humidity hasn't been definitively linked, but this is one issue that bears some additional consideration when deciding humidity control level.

Answer 3

From experience in a previous life as a datacentre supervisor, very low humidity levels can increase the risk of static discharge. Somewhere around 40% is considered optimal.

Answer 4

Actually Intel has been doing some research around datacenter environmental control requirements which has produced some very surprising results - i.e. that maybe datacenters in some locales don't need any environmental controls at all...

Answer 5

Less than 30% typically is too dry and creates greater chance for static buildup and static discharge by personnel which could be very bad.