Engineering Datacenter environmental requirements?

[Dave]

Greetings,

I'm interested to know what kinds of environmental standards people try 
to maintain for "engineering lab"-type machine rooms, compared with on- and 
off-site 24/7 production datacenters.  

We have a couple of megawatts worth of equipment running in various
labs of various ages and designs, on which software development and QA
is performed.  Their rank in the scheme of things is low enough that they're 
not on UPS, redundant power or networks, etc.  However, we're still negotiating 
with the facilities people on whether the HVAC and environmental monitoring they 
gave us (long story) is adequate.  I don't have much experience in "real" datacenters, 
so I'm looking for advice.

TIA-942 calls for 20-25 degs. C (68-77 F) at the intake of the gear,
with a maximum rate of change of 5 C (9 F) per hour, and with 40% - 55% RH.  

How hard do y'all work to provide that in your engineering labs?  Especially 
those of you who are here in California or other areas where Electricity is 
more expensive.

Thanks.