NFPA 850 and 20 numbers of jockey pump ? 5

[FLUD]

As I understand demand from NFPA is :

1 main electrical pump (primary)
1 main diesel driven pump (secondary/standby)
1 small jockey pump (only 1 pump is enough ?)

 

[TravisMack]

I a setup as you have described, one jockey pump is enough. Remember, this is only a maintenace pump. It will be connected to the common discharge piping of the fire pumps.

 

[trashcanman1]

As previously stated, the jockey pump is just for small leaks. It should be sized for less than the discharge of a head. A flow equal to a head discharge means a SERIOUS leak or, a head is actually open.

 

[DavidCR]

I´ve seen that is a general practice to use a electrical main pump and a diesel as a secondary but I´m not sure where it is required, or if this is required by some standard for power plants, so I´ll appreciate if somebody can clarify on this. Of course, if possible I would recommend both pumps, but as I see, just one diesel (with the jockey) would be enough if you are thinking of a minimun requirement with a limited budget.

About the jockey, I´ve seen that in general for power plants a 3hp electrical listed pump is commomnly used, but I don´t know how it is sized from the possible leaks spected as the NFPA 20 recomends.

 

[MJDLP]

According to NFPA code 24, chapter 5.6: "A single automatically controlled fire pump installed in accordance with NFPA 20 shall be an acceptable water supply source.", The NFPA code requires just one pump. Maintenance "without delay" is required of course when necessary. More generally speaking, the design of your fire water system should be based on a fire and explosion protection philosophy describing other facilities and operation philosophy as well. (fire brigades, manning etc.) However my experience is that on chemical installations and refineries there are the pumps that you describe. Most clients want to have two fire water pumps with independant power supply and a jockey pump. Check chapter 5 of NFPA 20 and the Appendix A that gives comments on chapter 5 for more information.

Regards,

 

[HFP13]

I think and as NFPA says, one 1 jockey pump will be enough. Remember that this is for pressure maintainance service only and will run for a few minutes only. If your concern is back-up, you still don't need an extara jockey pump because once it fails your fire pump will run.

rgds

 

[LCREP]

Many times Insurance Companies require a secondary water supply when values are above say $150-200 million in certain types of occupancies i.e. warehouses, manufacturing, etc. Often you will see an electric pump with a diesel back up. Sometimes on the same water main, sometimes on a different main. Common is to have the electric pump off the city water main with a suction tank and diesel pump as back up. Is it required by code NO, but as an insurance carrier I can ask for more then the code if our underwriters deem it necessary. If the client does not want to do it then they may pay more for insurance premium, find another carrier, or split the overall coverage with several carriers, each taking a piece of the risk.

The concern is if the primary water supply is lost, i.e. water main break, power failure the facility will have fire protection.

 

[pierrepaul]

The pumps questions shows an interesting difference between the US rules and the rules applicable to some European countries such as France, where the standard states that in most cases two pumps (plus the jockey) are necessary. In the US, the insurer is more deeply involved in the definition of the requirements and will ask for two sources for significant risks.

Brice FRANC
SPK Engineering

http://www.spk.fr/Protection incend...e incendie/sprinkleur/systemes sprinkleur.htm

 

[HFP13]

I think some of us are not satisfying the question of the originator. What he is asking is if only one jockey pump is enough fo an installation. Electrically driven primary fire pump and Diesel-driven secondary fire pump set-up for large facilities is a usual practice for system reliability. Optimum level of protection for life and properties is needed for such a huge facility. However, to have a redundancy for a jockey pump will only complicate control schemes and is to no avail anyway.