Pump Head Calculation

Add vertical height + frictional losses for total head.

The engineer who is selecting the pump is responsible unless somebody else takes responsibility.

Do not forget suction lift or suction head in your calculations.

Pump head some times refers to the dead head pressure. That is the pressure the pump will do with no flow. Close the discharge valve and read the pressure between the discharge valve and pump.

Then how to convert pressure in to head.

10.2m = 1bar = 100 kPa

1 psi = 68.95 mb

Now you can do the math from there....

also the residual pressure (if any) at the remotest outlet should also be considered in the head calcs.

27" water column = 1 psi. or 2'-3" = 1 psi. Divide Total Head by 2.3 = psi.

say 120 ft total head/2.3 = 52.2 psi/14.5 = 3.6 Bar.

sandeep how come you asking this? You must be jokeing.

Sorry, Sorry Sundeep. i made a mistake and thought M. Parthiban's next question.No wonder, that is why asked how come sundeep asking this. Sorry.

Hello M.Parthiban:

Welcome to you, this is a great place!

It is a 'Mechanical', psig pressure which can be converted to cfs/gpm. It works out at .433 psi per ft head.......

Ft head|psig at base of column. PSIG (Pound Per Square Inch).

Assuming Sea level Gravity at 14.7 psig. 1 psi = Pascal (6.894757 (kPa)SI Units.

1 ft .433--psig

2 ft .866--psig

3 ft 1.299-psig

4 ft 1.732-psig

5 ft 2.165-psig

6 ft 2.598-psig

7 ft 3.031-psig

8 ft 3.464-psig

9 ft 3.897-psig

10 ft 4.33--psig

Do you know how much head you have? In a small house with low ceiling the head is usually around 3/5 ft. In a place with say 12 ft high ceilings the head could be 6/8 ft.

You generally want to get as much head as possible, especially if it is not a pumped system. Gravity, plus low ceilings and raised shower/bath floor will lessen the potential 'head'. So you may need to raise the tank or water feed in the loft space (if you have one).

Can you tell me what size or schedule/type of pipe you refer to please?

Id's differ between Type K Copper and Type L Copper.

And Schedule 40 Pipe/Schedule 80 Pipe.

The Flow Rate differs accordingly.

Hello Ducon,

When guest mentioned the practical way to measure the head, then discussion take different mode. Which is also interesting but not for selection but for testing.

Anyway after asking that question I got a lot of information. Thank you.

Actually I was searching this site for him - www.pump-flo.com

In which you will get pump selection software even with variety of pumping material.

Because vapour pressure of material is very important aspect while selecting the pump.

Pump selection is a mechanical engineers specialty. depending on the application he should select the type of pump applicable and head calculations thereof. usually it is simply the total level deference between the intake and the delivery point (geographic head they some times call it) + Plus head loss in the line pipe. the time sunction lift becomes important is when the pump is installed at some level higher than the liquid surface - NPSH (Net Positive Sunction Head as they call it in pump terminology) then beomes important. So, whereas a surface horizontal centrifugal pump installed at ground level lifting water or liquid from a tank below will have NPSH considerations to finction well, a submersible pump in same application will ofcourse be submerged and so sunction here is regarded as flooded and will not then have any NPSH or sunction lift problems. so depending on the application, please always consult your mechanical engineer to choose the appropriate pump type and do head calculations.

i have one pumping system, let say if the water level at the suction tank is RL=0m and i need to pump to the storage tank where the top water level is RL=30m through a pipe. However,the highest point of the pipe system is RL=40m. How to calculate the pump static head? is 30m-0=30m or consider the highest point of the piping system 40m-0=40m?

Hello jackng,

'Sandeep Lokhande' lists a site which may be of use. I have not checked this site out but it does sound as if it may be useful to you. And it is just a couple of posts before yours, OK?

www.pump-flo.com