PowerEdge Servers Ambient Temperature Operating Range

We're currently in discussion at work as to the ambient room tempertaure peak in which servers should start getting powered off.  We've been having some A/C problems.

 

I spoke to a Dell server rep who stated the PowerEdge ambient temperature operating range is 50 degrees F to 95 degree F.

 

Here are my additional questions from a computer room with 5 full racks of servers.

 

1.  The computer room can stay at 80 degrees F indefinately, the servers are fine?  (If so, why keep computer rooms at 70 F?)

 

2.  The computer room can stay at 90 degrees F indefinately, the servers are fine?  (If so, why keep computer rooms at 70 F?)

 

3.  If any answer to #1 or #2 is no then at what ambient temperature should servers be powered off?

 

If A/C is degraded or fails:

 

4.  At what ambient temperature should laptops be powered off?

 

5.  At what ambient temperature should workstations be powered off?

 

Thanks