type of pump to be use as fire pump

[mechanicaldup]

hi

what is the advantage of using a horizontal split casing pump as a fire pump for sprinklers instead of an end-suction centrifugal?

 

[Artisi]

The simple answer is NONE, unless it's a sprinkler system that has to meet a specific standard - ie, NFPA or similar and then you are dictated to be the standard..

Naresuan University
Phitsanulok
Thailand

 

[stewbaby]

I'm not a pump or firewater expert, but from my experience, my two cents are:

I'm thinking it is driven by flow and pressure demand only...in that end suctions efficiencies and therefore availability top out at flows below what split case allow. Lower flow (less than 2500 GPM) end suction might be better choice. Higher flow (more than 2000 GPM and upwards of 10,000) split case is the best option (and typically the only option).

I highly recommend going to a web sight such as the goulds site below, registering with their pump selection system (PSS), and trying some pump styles...model 3196 versus say model 3410.

http://www.gouldspumps.com/pss.html

If flow is where the two styles overlap in performance, it will just be a maintenance preference decision.

Stew

 

[Artisi]

Correction ..... dictated to be..., should read ..... dictated to by

Naresuan University
Phitsanulok
Thailand

 

[Harold53]

mechanicaldup
H Split pumps normally have a "flat curve" aroud its BEP, so its easy to comply the Fire Pump Code requirement to give 150% of its nominal Flow with a lowering of 35% of its nominal Head. However, some End suction Pumps may comply this spec. You just need to check if the pump is actually rated as a Fire Pump and so recognized for UL or similar.

 

[mk3223]

The type of pump is selected by the requirements of the pumping flow and discharge head. For the "fire pump", you may choose the NFPA code (UL) pump which has additional requirement for the pumping flow as mentioned Harold53, as well as the NFPA pump control system.
However, if agreed with the Fire Dept Authority, you could select suitable pump of any type for the system.

 

[hbw]

A fire pump must be FM /UL listed for firepump service per NFPA Standard 20. Likewise for the check valve, relief valve and controllers

 

[Artisi]

To get back to the original question - From a hydraulic consideration there is no advantage of using a HSC pump over and end suction pump.
Hovever, if the insurance underwriter stipulates a specific standard for the pump to meet - then maybe you are dictated to a particular pump style, but this is a complete new story.

Naresuan University
Phitsanulok
Thailand

 

[firepumprep]

End suction design has whats known as a overhung impeller with the bearing only on one side of the rotating element. As the load on this type of pump increases so does the deflection of the rotating element. They are primarly used where space is limited.

Split case pumps are better performing, longer lasting and easier to service. They unlike end suction have bearings on both sides of the rotating element and dont have the problem of deflection. Their downside is that they are big and need more room.

 

[Artisi]

and the major disadvantage of split case pumps is that they tend to be more expensive.


Naresuan University
Phitsanulok
Thailand

 

[stanier]

Ypu will find that the split case pump will have a higher moment of inertia and will thus cause fewer waterhammer events.

Geoffrey D Stone FIMechE C.Eng;FIEust CP Eng

http://www.waterhammer.bigblog.com.au

 

[BigInch]

Have a look at Goulds fire pumps,

http://www.gouldspumps.com/download_files/Industry_brochures/ACPfire.pdf

Going the Big Inch!

http://virtualpipeline.spaces.msn.com