How do calculate the fire pump capacity?

Answer 1

The input power, that is, the power required to operate the pump should be stated in Hp (horsepower) on the pump's nameplate. It can also be calculated by the 3-phase power equation:

P(in Hp) = VI(1.73) = Rated Voltage x Rated Current x 1.73/ %Efficiency

If this is a consumer grade pump that operates on 120Vac, then the equation becomes P = VI, simply multiply the operating voltage, 120 x current (which is the number followed by the letter "A".

The nameplate might look something like this:

___________________

| |

| Make: xxxxxx |

| Model: xxxxxx |

| Volt: xxx |

| Amp: xxx |

| %Eff: xx |

| |

|__________________|

The output power, which really isn't technically power, but rated in Gpm (gallons per minute), or capacity should also be on the nameplate. If you have the make, model, and (not necessarily needed) the serial number (also on the nameplate) you could call the manufacturer's customer service dept. As an application engineer, I have contacted countless manufacturer's service dept's for assistance. It is now big deal to them, they will be happy to answer your questions.

If it is the absorbed power of the pump to allow you to select a suitable motor then this is a function of the generated head, flowrate, specific gravity of the fluid and the pump efficency from the OEM / pump performance curve.

For those of us not in the US or using English units then the power can also be specified in kW.

In simple terms Power (kW) = Flow x Head x SG / (367 x Effy)

Where Flow is in cubic metres / hour, head is in metre, Specific Gravity (SG) being a dimensionless unit - cold clean water SG = 1 and efficency as a % from the curve or other means.

If you are trying to evalaute wire to water efficency then you can set efficency in the equation above to 1 and then ratio the input (measured power) to output power (calculated water horse power) to obtain the overall efficency.

Answer 2

Calculate or calibrate? Calculate - apart from reference to tables for the pump, impossible. Calibrate - get a stop-watch and a very big bucket, switch on and stand back. There should be a capacity on the plate on the pump, or a design or model number that you can use to get a capacity figure, either from a catalogue or the manufacturer.

Answer 3

When calculating the discharge of a centrifugal pump, the pressure at any point in a liquid can be thought of as being caused by a vertical column of the liquid which, due to its weight, exerts a pressure equal to the pressure at the point in question. The formula for calculation is: multiply the pressure in psi times 2.31. Divide this total by the specific gravity.

Answer 4

Conduct a test as follows:

1. Place the suction side or suction hose of the pump into a fluid.

2. Allow the pump to pump the fluid into a the first container until the pump is pumping a steady fluid flow.

3. Switch the output hose of the pump to an adjacent empty (second) container whiile simultaneously starting a counter (i.e. count up timer). You may need a friend to operate the timer if you aren't sufficiently coordinated to manage both actions.

4. Allow the pump to pump the fluid for whatever amount of time you desire (e.g. 40 seconds).

5. Measure the fluid volume in the second container.

If the volume of fluid from the second container is 3 gallons and it took 40 seconds to pump the 3 gallons, then do the following calculations:

3 gallons / 40 seconds = .075 gallons/second

Since most pumps are rated by the gallons per hour that they pump, do the following calculation:

.075 gallons/sec * 3600 sec/hr = 270 gallons/hr

Note: There are 3600 seconds in 1 hour (60 sec/min * 60 min/hr = 3600 sec/hr

Answer 5

I want the formula related to centrifugal pumps power,capacity and voltage.

Answer 6

2999sq/ft