Commercial buildings may use diesel or natural gas generators to support emergency and life-safety power, however can they use a battery based energy source that can support the same loads, runtime, etc.?
I believe they can as long as that battery based power system is a level 1 system per NFPA 111
Thanks Andrea, what inspector typically has jurisdiction over this matter to make the call - electrical, fire?
Arrow is correct you may have to deal with both the electrical Inspector to assure that the USP or genorator is installed pet code and the fire inspector who makes sure that they are maintained properly and tested as per code
As a fire inspector I would always check the backup genorator and UPS to make sure there were no problems because they powered the smoke detection systems, fire alarm systems, exit signs, and emergency lighting.
Also make sure you have the appropriate maintenance and test records on hand.
Off Post Fire Prevention Inspector
Department of Defense ( RET. )
Yes, battery can absolutely be used instead of a generator. They call that a UPS system. I have delete with this issue many times and what you will find is that the design really depends on what you are putting on it. The generator many times will be cheaper depending on the load. But let me give you an example of where I use UPS as standard building design. I put all my emergency lighting on UPS, why it cut down on the maintenance cost on the battery pack lights on the wall ceiling mounted. I have done this all over the world, many times....
If i do have a generator and UPS, i run the gene power through the UPS also, so when or if the gene gives up that is when I carry load on the UPS. Also, as a FYI, if you need uniteruptable power UPS is the way to go because it is instantanous. Generators can be up to 10 secs for life safety ramp up time, that can be a long time and some of your processes like maybe computers or in my case chemical reactions you can not have a blip
Thank you Aaron. Are there any minimum standards that need to be followed – N+1, double conversion, etc. NFPA 111 doesn’t provide much in the way of those criteria. Is it the electrical inspector of fire department that has final say, or who is AHJ?
Good question I am assuuming this is a USA installation question. In which the answer is both, the Electrical inspector is required to ensure the system is installed to the NEC requirements in some place it maybe the same AHJ for fire. Fier code guy confirms life safety is addressed. Best recommendation would be to ask your construction inspectors because every town and city can be a little different. The only way for the UPS system to be acceptable is it has to meet the life safety requirements if that is what you are using it for ....so emergency lighting needs to stay on for 90 minutes, have the correct coverage, etc..Typically who ever the engineer is who is stamping your drawing will confirm it meets all the requirements. There is no N+1 requirements, but UPS will need to cover dedicated circuits and you should have change control over your panel, people will always ask to get more stuff on the UPS as they deem stuff critical, but you have to maintain the power suppy requirements for lifesafety, which is also why you are required to test and inspect the system.
Hope this helps, I would get an electrical engineer to design and confirm compliance.
Thanks Aaron, much appreciated. Primarily a US question, though has implications beyond also. The life safety systems would be designed by the appropriate licensed party, I’m just focusing on the opportunity of using a stored energy solution as the power source. Glad to hear a UPS type system is acceptable. Does it have to be dedicated to the life-safety, or can it also support other loads or applications, say small data centers for tenants within a building?
Usually not a problem to combine. AHJ could could request separation but I have doen it both ways. I prefer to combine
There are two sources of alternative power as defined under the NFPA: Back up power and emergency power. The former supports non-essential services but required by the authority while the latter supports fire safety systems.
All of the following are acceptable emergency power under the NFPA:
Where we have put more load on UPS or generators used for emergency power (primarily to ensure a good load on the generator), we have had to put load shedding devices in line to drop non-life safety loads if the generator becomes to loaded. This use was in distribution centers where we needed to move between loads (small but important data closets, charging equipment, baling cardboard, running conveyor systems, lighting, etc....) depending upon time of day and need.
The AHJ just wanted us to prove if we started to exceed the generators load (we set this to start around 90% of rated load), that non-essential loads would drop off and life safety would be covered. We could then manually come in and load up the generator as needed to ensure we kept greater than 30% load as much as possible.
Kind of neat to as you can add and take off load as required. It also keeps you engaged in the operation of the generator in critical environments so you are more aware of your burn of fuel. Worked great during Hurricane Sandy up the East coast.
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