CR4® - The Engineer's Place for News and Discussion®


Previous in Forum: Instrumentation Cable   Next in Forum: CNC Press Break
Close
Close
Close
6 comments
Active Contributor

Join Date: Dec 2016
Posts: 11

Fire Pumps in Load List

12/28/2017 8:05 AM

I have 2 No's of Fire pumps. One is duty pump and the other is standby pump. Do I have to consider both as standby pumps, as both pumps under normal conditions would not run. Could those be included under "Continuous load" or "Intermittent load".

Register to Reply
Pathfinder Tags: fire pump Load List
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain, and now disconnecting ["brexit" - ugh] as Little England and Wales (not too sure about Wales bit, either). Kettle's on.
Posts: 26914
Good Answers: 707
#1

Re: Fire Pumps in Load List

12/28/2017 10:52 AM

The Control Philosophy document for the installation will say. That document cannot be seen from here.

  • It is the practice to have these on their own fuel supply such as diesel/gas-oil in many cases, so that the thing will continue running after the fire has burnt out the power supply cables and the mains has failed, thereby maintaining a fire suppression system in the absence of electricity.
__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Guru

Join Date: Oct 2008
Posts: 40289
Good Answers: 1596
#2

Re: Fire Pumps in Load List

12/28/2017 10:56 AM
Register to Reply
Guru
Engineering Fields - Electrical Engineering - Been there, done that, still doing it. Engineering Fields - Control Engineering - New Member

Join Date: Dec 2008
Location: Long Island NY
Posts: 12353
Good Answers: 778
#3

Re: Fire Pumps in Load List

12/28/2017 12:01 PM

In most regions, fire pumps are a special class of electric loads that have their own set of safety regulations. Often any type of circuit protection between mains power and fire suppression and detection systems are forbidden by the regional code. You've not identified your region. Nor have you identified why you are tasked with identifying the type of load this safety system should be considered. Lives are at stake with any safety system. Only qualified individuals should touch, let alone design a safety system.

__________________
"Don't disturb my circles." translation of Archimedes last words
Register to Reply
Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 19778
Good Answers: 1155
#4

Re: Fire Pumps in Load List

12/28/2017 2:50 PM

IMO the load should be sized for worst case scenario....

__________________
Life is like riding a bicycle. To keep your balance you must keep moving. A.E.
Register to Reply
Active Contributor

Join Date: Jun 2014
Location: South Korea
Posts: 18
#5

Re: Fire Pumps in Load List

12/28/2017 8:15 PM

In practical, Fire pump is considered as 'Emergency Loads' powered by EDG (or UPS). When u make calculation of Emergency Loads, Fire pump capacity (kW) shall be included. And no need to see the standby pump because the both pumps do not operate at the same time.

Thanks,

Register to Reply Score 1 for Good Answer
Guru

Join Date: Jul 2006
Location: Eastern Kansas USA
Posts: 1125
Good Answers: 99
#6

Re: Fire Pumps in Load List

12/28/2017 11:36 PM

Selk,

Others have already asked for your location, because you have to comply with the rules for your location and we come from all over the world.

Question 1: Do the controls permit both pumps to run at the same time? If so, then you must include both in your load calculations.

Question 2: What is the source of power for the pumps? Generally in the USA this source has to be independent of the main building's electrical service.

Question 3: What is the overcurrent protection in the circuit feeding each of the fire pumps? The general view is that you want the pump and motor to keep trying to start even if it cannot, because it may successfully run and get water to the fire. So the overcurrent protection is usually set high enough to carry the locked-rotor current of the motor indefinitely--this appears wrong to the uninitiated but is correct.

All in all, I would include the fire pump motors as continuous load and put this in at a value much higher than the motor's full load amps. BUT check with your local fire inspector--they greatly prefer questions to things that burn.

--JMM

Register to Reply
Register to Reply 6 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

jmueller (1); lyn (1); moons (1); PWSlack (1); redfred (1); SolarEagle (1)

Previous in Forum: Instrumentation Cable   Next in Forum: CNC Press Break

Advertisement