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minimum continuous stable flow for fire water pump

minimum continuous stable flow for fire water pump

minimum continuous stable flow for fire water pump

(OP)

What is the minimum continuous stable flow for fire water pump? Is there any requirement if so howmuch in terms of percentage of rated flow?

The firewater pump is on an offshore platform.

Thanks in advance for you replies.

RE: minimum continuous stable flow for fire water pump

I would be interested in knowing why you need to know the minumum continuous flow for a fire pump, I would think that a fire pump is either off(hopefully always other than for maintenance) or on when needed in which case who cares what the minimum flow rate is.   

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)  

RE: minimum continuous stable flow for fire water pump

refineries, tank farms etc. may require up to 5,000 gpm and  20 psi or higher

RE: minimum continuous stable flow for fire water pump

Minimum Stable Continuous Flow can only be provided by the pump manufacturer for the specific pump in question.  If this is a jockey pump that needs to keep the system pressurized, it would normally have a flow controlled spill-back to keep it above its required minimum.

Johnny Pellin

RE: minimum continuous stable flow for fire water pump

20 psi is the minimum pressure which the fire departments need for their pumper trucks so as not to collapse the water mains.  

RE: minimum continuous stable flow for fire water pump

In a situation where a fire pump is continuously in operation due to poor system design or being periodically tested against a closed discharge valve, to prevent serious damage,a minimum of 12% of duty flow (at ambient temperature)should be leaked off back to inlet source to prevent serious damage. This situation should not occur as its both expensive on energy and harmful. The pump should be either on in the event of an emergency of off.  A much smaller jockey pump should be in the system to maintain the system pressure in the event of any leakage etc.  

I have know fire pumps in the UK to be tested weekly for 1 hour against shut valve.  One example was an end suction single impeller pump of 25kW that ran so hot due to lack of forward flow that you could not bear your hand on the casing for more than a few seconds.  The pump impeller eventually destroyed itself.    

RE: minimum continuous stable flow for fire water pump

And what useful information could ever be gained from running a pump at CV for 1 hour other than confirming the stupidity of the owner / operator / maintainance staff?

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)  

RE: minimum continuous stable flow for fire water pump

Yes, unbelievable the stupidity of some people.  Typical example of so called 'engineers' not knowing the first thing about the kit they are looking after. Nevertheless they put a lot of business our way!

RE: minimum continuous stable flow for fire water pump

The flow rate is not specified by the Classification societies in the case of Offshore platforms or rigs., But the minimum outlet pressure at the highest point of the fire system installation
(usually the helideck monitors) should be 7bar.

Offshore Engineering&Design

RE: minimum continuous stable flow for fire water pump

it should be noted that in a fire main closed ring circuit, the highest point should be served first. This prevents an outlet at a lower elevation short circuiting the fire water supply and preventing pressure attainment at the highest point.

Offshore Engineering&Design

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