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Electrical feed to life and safety 1

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Rehacayli

Mechanical
Aug 1, 2013
14
Hello,
I've got a specific question and looking for a possible confirmation from NFPA. I have a design concept in hand;

- we have a lot of generators in the project. to reduce them we have come up with an idea to use the generators for business continuity and in case of fire these generators would switch to be used in life safety in need. It means if I have 3 generators for business continuity and 2 generators for life safety need, instead of having 5 generators, I'd like to use 3 generators and if a fire signal or a evacuation scenario is activated those three would serve life and safety instead of business continuity as all the building would be evacuated anyways. Is this permitted according to NFPA or do I require a separate generator set for the life and safety?

- another question is, I have a disagreement with our designer. he claims that we need to have a pump set feeded from mains and a pump set feeded from generator back-up. I claim that if we have a electrical pump feeded from mains and a diesel engine pump, it is enough. in case of electrical cut, the diesel engine pump will be online. He says that this is not permitted in NFPA as there can be a time that diesel engine is under maintenance and generator can't back up the fire system. I think that this is over safety and I don't think NFPA says something like that.

Can I have some ideas or confirmation for these? thanks in advance.
 
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"He says that this is not permitted in NFPA as there can be a time that diesel engine is under maintenance and generator can't back up the fire system" wrong. One diesel pump and one mains-fed pump is a standard set-up in USA. You only maintain one pump at a time, and notify the protected area(s) that they are on one pump, renotify when both are back online.
 
Could there a reason for redunancy? There may be situations where a designer requires more than the minimum set forth in NFPA depending on the hazard,business type,etc.
 
You can always make a case for redundancy. Just ask "When have both the diesel and the electric pumps failed simultaneously? At anybody's location?". Unless sabotage/artillery/air strikes were a credible scenario, I am comfortable with 2 pumps to do one job.
 
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