Number of Pumps ( duty + standby) 2

[mirza057]

Guys,

What is the basic criteria to decide the number of pumps.

I mean, 1 duty + 1 Standby or 2 duty + 1 standby.

How to be decided?

 

[hydrae]

use single fault criteria

largest pump out of service and still operate as designed

so 1 duty + 1 standby is 2 larger pumps
or 2 duty + 1 standby is 3 pumps, each half the size of the situation above

the second setup is
total installed hp is 1/3 less, smaller motors, smaller wires, smaller controls
easier to get replacement parts, easier to replace components ect,
but uses more controls, more valves, more piping connections, and takes more space

see which has less lifetime cost

Hydrae

 

[PEDARRIN2]

That is a very open ended question which you should elaborate so you can receive better responses.

Are you talking about domestic booster pumps, hot water recirculating pumps, or something else?

Mainly, it depends on the building usage characteristics (flow rate, peak load, intermittent requirements), ability to withstand down time, etc.

There is a lot of difference between an office building and a hospital when plumbing pumps are required.

 

[LittleInch]

The basic criteria is how important is continuity of service and how long does it take to swap outa pump.

A fairly common principal assuming you need total full capacity available at any one time is N+1. What N is is up to you and could be 1 to 10+. You might determein that three pumps are needed for full capacity, but often only two so go for 3 x 1/3 and then swap one out if required and survive on two.

Lots of options available to you - decide what is important to you first - guaranteed maximum capacity or dollars spent.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1gibson]

2 x 100% (one running, one installed spare) or 3 x 50% (two running, one installed spare.)

The 2 x 100% gives you more flexibility to run at higher flows, the 3 x 50% gives you more flexibility to run at lower flows.

Economics is the obvious answer, but system flexibility should be considered as first, and may or may not override the economics.

 

[dbill74]

The fewest number of pumps to do the job +1.

And client requirements.

 

[mirza057]

Thank you guys