I am looking for a means to provide backup power for egress lighting for a warehouse/dispensing pharmacy project I am working on. I had planned to use an inverter. I currently have two UPS units in this same building for security data rack backup power and was asking myself why I couldn't use a UPS unit for the egress lighting as well. Can anyone think of some disadvantages of using a UPS for egress lighting? The UPS unit would provide power to a lighting panel and would provide 90mins of backup power as required by Code. Any comments would be appreciated.
UPS vs. Inverter
- Thread starter bfletcher
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Buck Parrish
Senior Member
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- NC & IN
You would want to use a seperate UPS for your lights.
Depending on how many amps your lighting panel is you would have a large UPS.
Depending on how many amps your lighting panel is you would have a large UPS.
gar
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Whether you use an inverter or UPS, the UPS is probably an inverter. UPS is a rather broad term and could include an engine-generator combination.
First, consider using LED lights to greatly reduce your energy requirements.
Whether you use an inverter with external battery or a UPS with internal battery there has to be enough energy storage to meet your time requirements. Suppose you had 500 W load and need 1.5 hours of run time, then the energy required is 750 W-hr. A large car battery might provide 12 * 80 = 960 W-hr. Long term reliability of low cost computer UPSs is not very good.
Advantages of an inverter. Probably can get one with a continuous rating that may mean something, easy to add or enlarge battery if necessary.
Why not use low voltage lamps or LEDs, eliminate inverter, thus eliminate the inverter losses, and also improve reliability.
.
Whether you use an inverter or UPS, the UPS is probably an inverter. UPS is a rather broad term and could include an engine-generator combination.
First, consider using LED lights to greatly reduce your energy requirements.
Whether you use an inverter with external battery or a UPS with internal battery there has to be enough energy storage to meet your time requirements. Suppose you had 500 W load and need 1.5 hours of run time, then the energy required is 750 W-hr. A large car battery might provide 12 * 80 = 960 W-hr. Long term reliability of low cost computer UPSs is not very good.
Advantages of an inverter. Probably can get one with a continuous rating that may mean something, easy to add or enlarge battery if necessary.
Why not use low voltage lamps or LEDs, eliminate inverter, thus eliminate the inverter losses, and also improve reliability.
.
brian john
Senior Member
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- Kilmarnock, Va
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- Retired after 52 years in the trade.
I would think the inverters are actually listed for emergency lighting use and they are cheaper than a UPS an lighting inverter is an interruptible lighting system IPS.
This sounds like its time for a sales pitch...
This sounds like its time for a sales pitch...
I might work up the cost of a generator install compared to a inverter/battery bank/charging system. I might be willing to bet the install and lifetime maintenance cost of a generator would be less. As far as EM egress lights put up whatever is the best cost.
This sounds like its time for a sales pitch...
I might work up the cost of a generator install compared to a inverter/battery bank/charging system. I might be willing to bet the install and lifetime maintenance cost of a generator would be less. As far as EM egress lights put up whatever is the best cost.
Buck Parrish
Senior Member
- Location
- NC & IN
VinceS said:
Me too, But the OP is an engineer. They think different then us EC's.:smile:
weressl
Esteemed Member
The UPS is normally used for critical service equipment. The more complex the wiring system, the more potential there is for failure. Why would you want to jeopardize the service to your critical equipment by lowering the reliability of the UPS service with extensive lighting wiring run all over the facility? Any shorts on that system could suck the voltage down and interrupt your critical power. If your lighting is the type that uses ballast, then the additional harmonics could also deteriorate the quality of your critical power.bfletcher said:
Cost per kW is much higher for an UPS grade inverter than one used for lighting.
That being said, if after careful evaluation you still choose to go ahead with the UPS service and your system is a large three phase one, I would install a transformer with a static switch to power the lighting service.
One consideration: some legally required emergency lighting system may require the components to be listed for emergency service, so make sure that all components of that system are in compliance.
DanZ
Senior Member
Silly question, but is there a reason you can't use an emergency light fixture, or a fluorescent light fixture with a built in battery back up? I know Lithonia has that option on a few fixtures.
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