minimum continuous stable flow for fire water pump 1

[hemvig]

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.

 

[Artisi]

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.)

 

[cvg]

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

 

[JJPellin]

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

 

[chicopee]

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

 

[pumpman50]

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.

 

[Artisi]

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.)

 

[pumpman50]

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!

 

[chief]

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

 

[chief]

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