"emergency" generator vs. battery E-lighting 5

[Senselessticker]

Anyone have any long term cost comparisons on emergency generator vs. battery powered emergency lighting and exit signage? This is about a 100K sq. ft. commercial office building (in conceptual design phase). Some folks here are getting concerned over the maintainance/testing cost requirements to keep the generator designated as "emergency" as opposed to "stand by" only.

I'm "guessing" that its cheaper in the long run to just keep the generator up to emergency status and not use battery powered E-lights/signage. Anyone know of literature / study / report that supports such an idea for a similar sized building?

Thanks for any help!

 

[itsmoked]

Neat item Ron!

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[EEJaime]

davidbeach,

The reason I said a generator system could be cost prohibitive is that he has a 100ksf comercial office building. At 1.2 w/sf,(per California T-24). That's a maximum lighting load of 120 kVa. Most offices will not have emergency lighting, usually only exit corridors, lobbies, critical spaces etc.... will require egress lighting. So even if the total egress lighting load was 5% of the total, that's only 6 kVa, even at 10 kVa we find inverters to be the most economical solution. And we don't have to worry about HID sources.

EEJaime

 

[davidbeach]

If all there was were 10kVA of lighting, nothing else, a central battery system would probably be the most economical. But there could be a computer room that wants standby power; elevators, stair pressurization and elevator pressurization fans, other things; none of which work well from a central battery system.

 

[EEJaime]

That is all very true, but the original question was specifically about exit pathway lighting and signage. There is no doubt that batteries cannot power all emergency loads in a building. When we do data centers we usually have dedicated UPS units, either single or redundant depending how critical the facility is. Most IT managers hate sharing their systems and generators don't work for them either as the transfer-time dropout will lose critical data.