At 12:07 PM -0400 7/25/07, Leo Bicknell wrote:
The more "urban" an area the more likely it is to have strict fire codes. Typically these codes require a single EPO for the entire structure, there's no way to compartmentalize to rooms or subsystems.
For high-availability sites (Tier III, Tier IV per UpTime Institute), EPO's are one of the most common reasons for outage. I'd highly recommend APC's paper <http://www.apcmedia.com/salestools/ASTE-5T3TTT_R2_EN.pdf> on the topic. Short-version is that its a safety issue for room occupants and responders. More mature codes tend to require such, particularly in the presence of UPS gear which can be energized unbeknownst to fire fighting personnel. If you don't have water-based fire suppression, have normally unoccupied spaces, and are continuously manned, it's sometimes possible to pass on having an EPO. YMMV by inspector. /John