Fire Pump

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mshields

mshields

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Boston, MA
My understanding about Fire pumps and backup power for them.

To my knowledge they are only required to be on a generator if serving a high rise. True?

Also, can one in lieu of a generator, connect the fire pump ahead of the MCB?


Thanks,

Mike
 
OK did some homework but also a follow up questions

OK did some homework but also a follow up questions

Per NEC Article 695.3,A, 1 you either need, and this is regardless of type of building:
(1) A dedicated service
(2) On site Power Production Facility (not an on site standby generator in that it is the Normal source for something. So this is a generator dedicated to the fire pump
(3) Dedicated feeder off of a service other than the buildings service.


BUT a fire pump is not, I believe, an "Emergency" load unless it's a high rise OR a Hospital correct. And only once it's identified as being an "emergency load" must it be backed up on a "standby" generator. True?
 
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mshields said:
Per NEC Article 695.3,A, 1 you either need, and this is regardless of type of building:
(1) A dedicated service
(2) On site Power Production Facility (not an on site standby generator in that it is the Normal source for something. So this is a generator dedicated to the fire pump
(3) Dedicated feeder off of a service other than the buildings service.


BUT a fire pump is not, I believe, an "Emergency" load unless it's a high rise OR a Hospital correct. And only once it's identified as being an "emergency load" must it be backed up on a "standby" generator. True?
Click to expand...

False. The requirement for having an alternate power supply to a fire pump is found in NFPA 20. The height of the building or weather it has an "emergency" system requirement is not relevent. I recall that NFPA 20 says something along the line of if there is more than 4 hours per year of POCO outage (must be documented) you must have an alternate source of power. It has been my experience that this is very dependent on the AHJ view of the reliability at the location. Keep in mind that adding an alternate source of power for a fire pump comes with a lot of very specific design and installation requirements in addition the already complex requirements for the wiring of fire pumps.
 
texie said:
False. The requirement for having an alternate power supply to a fire pump is found in NFPA 20. The height of the building or weather it has an "emergency" system requirement is not relevent. I recall that NFPA 20 says something along the line of if there is more than 4 hours per year of POCO outage (must be documented) you must have an alternate source of power. It has been my experience that this is very dependent on the AHJ view of the reliability at the location. Keep in mind that adding an alternate source of power for a fire pump comes with a lot of very specific design and installation requirements in addition the already complex requirements for the wiring of fire pumps.[/QU

Oops, I wrote weather-should have been whether.
Click to expand...
 
hmm

hmm

I'll have to take a look at NFPA 20 and if it is referenced in it's entirety for the state of, in this case, Rhode Island. However what you say is in direct conflict with the NEC. 695.3 allows for 3 categories of power supply to a Fire Pump.

A) A separate service or connection ahead of the service you already have to the building. On-site power production (i.e. a dedicated genset) and then one I'm not sure when it would apply but it is a dedicated feeder from a separate service.

B) Multiple Source which includes an Individual source plus On-Site standby generator. So this would be the option that you are suggesting always has to be taken; if I understood you correctly.

C) Is a special case for Multibuilding Campus-Style Complexes.


But "A" is a perfectly viable choice and it's certainly true, and you see it all the time.

From this, I conclude that a Fire Pump is not, by any means, always regarded as an "Emergency" load insofar as that word triggers the application of NEC Article 700. It is rather a special case.


By the way, what is POCO?
 
mshields said:
My understanding about Fire pumps and backup power for them.

To my knowledge they are only required to be on a generator if serving a high rise. True?

Also, can one in lieu of a generator, connect the fire pump ahead of the MCB?


Thanks,

Mike
Click to expand...

texie said:
False. The requirement for having an alternate power supply to a fire pump is found in NFPA 20. The height of the building or weather it has an "emergency" system requirement is not relevent. I recall that NFPA 20 says something along the line of if there is more than 4 hours per year of POCO outage (must be documented) you must have an alternate source of power. It has been my experience that this is very dependent on the AHJ view of the reliability at the location. Keep in mind that adding an alternate source of power for a fire pump comes with a lot of very specific design and installation requirements in addition the already complex requirements for the wiring of fire pumps.
Click to expand...

Texie is right. If the utility company is not considered a "reliable source of power," then an alternate power source is required. Normally, this alternate source of power is a genset. If under the IBC and the building is a high-rise, you are required to connect the fire pump to a standby source. When I design fire pump connections:

If the utility is considered a reliable source of power, I bring service conductors directly to the fire pump controller.

If the utility is not considered a reliable source of power, I bring service conductors directly to the normal side of the ATS for the fire pump controller, have a set of lugs installed at the genset, and bring conductors from the genset to the emergency side of the ATS for the fire pump controller.

Connecting the fire pump ahead of the main is permitted by the NEC, but is not a substitute for a genset. Only whether or not the utility company is considered reliable or the IBC/high rise requirements will dictate when a genset is required.
 
Diesel?

Diesel?

If this is a design question and a choice has not been made, you might consider a diesel powered fire pump. Even if the jockey pump is electric, choosing a diesel fire pump may reduce many of your headaches.
 
Generator requirement

Generator requirement

Jason - regarding your comment:
"Connecting the fire pump ahead of the main is permitted by the NEC, but is not a substitute for a genset. Only whether or not the utility company is considered reliable or the IBC/high rise requirements will dictate when a genset is required. "

"Reliable source" is subjective and therefore left to the whim of first the engineer but ultimately the AHJ (which means the engineer should coordinate with the AHJ during design). That said, I find it hard to believe that most utility systems in the United States would not be considered "a reliable source" unless it is your contention that there be a written guarantee that there will never be an outage. If the intent of the code was for the latter, it's my contention that they'd simply not allow a sole source.

But clearly per 695.3(A) they do allow a single source of power. I have seen many such applications. No way, is a generator always required when you have a fire pump.


Mike
 
gadfly56 said:
If this is a design question and a choice has not been made, you might consider a diesel powered fire pump. Even if the jockey pump is electric, choosing a diesel fire pump may reduce many of your headaches.
Click to expand...

Now, that's a one-shot that will solve your fire protection worries! You beat me in posting that! TY.
 
mshields said:
Jason - regarding your comment:
"Connecting the fire pump ahead of the main is permitted by the NEC, but is not a substitute for a genset. Only whether or not the utility company is considered reliable or the IBC/high rise requirements will dictate when a genset is required. "

"Reliable source" is subjective and therefore left to the whim of first the engineer but ultimately the AHJ (which means the engineer should coordinate with the AHJ during design). That said, I find it hard to believe that most utility systems in the United States would not be considered "a reliable source" unless it is your contention that there be a written guarantee that there will never be an outage. If the intent of the code was for the latter, it's my contention that they'd simply not allow a sole source.

But clearly per 695.3(A) they do allow a single source of power. I have seen many such applications. No way, is a generator always required when you have a fire pump.


Mike
Click to expand...
Yes, "reliable source" in the context of a fire pump power supply can be somewhat subjective and that's why I indicated in my previous post that the AHJ usually has a lot of say on this, in addition to NFPA 20.
No, an alternate source is not always required. And it does not always have to be a generator.
Yes, the normal supply to a fire pump always has to be ahead of the service disconnecting means.
Yes many an address in the US can't meet the NFPA 20 requirement without an alternate supply.
 
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gadfly56 said:
If this is a design question and a choice has not been made, you might consider a diesel powered fire pump. Even if the jockey pump is electric, choosing a diesel fire pump may reduce many of your headaches.
Click to expand...
True, diesel fire pumps can be a good choice in some applications. This has to be weighed against the higher (usually) capital cost and the higher maintenence cost. I've bee involved with some projects where this is the only viable option due to site conditions.
 
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