Fuel Pump Sizing Calculator

Calculator Inputs

Sizing Method

Connected Equipment Power kW

Average Load %

Specific Fuel Use kg/kWh

Number Of Units

Diversity Factor

Known Flow

Known Flow Unit

Fuel Type

Fuel Density kg/m³

Kinematic Viscosity cSt

Vapor Pressure kPa

Discharge Pipe Length m

Fitting Equivalent Length m

Suction Line Length m

Pipe Inside Diameter mm

Static Lift m

Suction Lift m

Equipment Loss bar

Required Outlet Pressure bar

Site Atmospheric Pressure bar

Safety Factor %

Pump Efficiency %

Motor Service Factor %

Reserve Runtime Hours

Operating Hours Per Day

Allowed Pipe Velocity m/s

Pump NPSH Required m

Example Data Table

Use Case	Power Or Flow	Pipe ID	Lift	Safety Factor
Small generator day tank	120 kW at 70%	25 mm	4 m	20%
Temporary heater farm	650 L/h known flow	32 mm	5 m	25%
Generator cluster transfer	500 kW at 80%	50 mm	8 m	30%
Remote storage refilling	18 US gpm known flow	40 mm	10 m	20%

Formula Used

Power based fuel demand: Fuel kg/h = connected kW × load factor × specific fuel use × units × diversity factor.

Volume flow: Normal L/h = fuel kg/h ÷ density kg/m³ × 1000.

Design flow: Design L/h = normal L/h × (1 + safety factor ÷ 100).

Velocity: Velocity = flow m³/s ÷ pipe area.

Friction head: Head = friction factor × equivalent length ÷ pipe diameter × velocity head.

Pressure head: Head = pressure Pa ÷ fuel density ÷ gravity.

Total dynamic head: TDH = static lift + friction head + pressure head.

Motor power: Motor kW = hydraulic kW ÷ pump efficiency × service factor.

NPSH available: NPSHa = atmospheric head − vapor head − suction lift − suction friction.

How To Use This Calculator

Select power based demand or known flow demand.
Enter connected power, fuel rate, or direct flow.
Select the fuel type and confirm density and viscosity.
Enter pipe length, fittings, suction length, and pipe diameter.
Add lift, outlet pressure, equipment losses, and safety factor.
Review design flow, total dynamic head, motor size, and NPSH margin.
Compare the calculated duty point with actual pump curves.
Download the result as CSV or PDF for project records.

Construction Fuel Pump Planning

A fuel pump on a construction site must move fuel safely and steadily. It may feed generators, temporary heaters, compressors, asphalt equipment, or storage day tanks. Good sizing starts with demand. The demand may come from engine power and specific fuel use. It may also come from a known transfer rate. Both methods need a margin because site loads change often.

Flow Demand

The calculator converts fuel mass demand into volume flow. Density matters because diesel, gasoline, and kerosene do not weigh the same. Connected power, load percentage, number of units, and diversity factor set the normal hourly demand. The safety factor then raises that value to a design flow. This prevents a pump from running at its limit during cold starts, peak loading, or unexpected refilling.

Head And Piping

Pumps must also overcome head. Static lift is the height between the source and delivery point. Pressure head represents filters, meters, valves, nozzles, or required outlet pressure. Friction head comes from pipe length, fittings, pipe diameter, velocity, viscosity, and flow pattern. A small pipe can create high velocity and large losses. A larger pipe often reduces heat, noise, and pump wear.

Power And Reliability

The tool estimates hydraulic power, shaft power, and motor size. Pump efficiency is important. A low efficiency pump needs a larger motor for the same duty point. The service factor adds another margin for demanding field use. The NPSH check warns when suction conditions may cause cavitation. Cavitation can reduce flow, damage impellers, and make the system unreliable.

Storage And Site Use

Fuel storage planning is linked to pump sizing. Daily use helps estimate refilling needs. Reserve hours show how long the system can run at the design rate. Site teams can compare several scenarios before ordering equipment. They can test longer hoses, extra fittings, higher elevations, and different fuels. Final selections should still be checked against pump curves, local codes, spill controls, grounding needs, and supplier data.

Field Checks

Before installation, confirm hose ratings, pump seal compatibility, strainer size, and access for maintenance. Keep suction runs short. Label valves clearly. Record every assumption. A clear record helps estimators, supervisors, and mechanics review the duty point safely during inspections and future changes.

FAQs

What is fuel pump sizing?

Fuel pump sizing estimates the flow, head, and motor power needed to move fuel from storage to equipment. It helps match a pump to site demand, piping losses, lift, pressure needs, and reserve requirements.

Which flow value should I use?

Use the design flow for pump selection. It includes the normal demand plus the safety factor. Normal flow is useful for fuel use, daily consumption, and storage planning.

Why does density matter?

Density converts fuel mass use into volume flow. Different fuels have different densities. Using the wrong density can understate or overstate the required pump capacity.

What is total dynamic head?

Total dynamic head is the total resistance the pump must overcome. It includes static lift, pipe friction, fittings, equipment pressure loss, and required outlet pressure.

Why is pipe velocity important?

High pipe velocity can increase friction loss, noise, heat, and wear. If the calculator warns about velocity, consider a larger pipe or lower transfer rate.

What is NPSH margin?

NPSH margin compares suction pressure available with pump suction pressure required. A low margin may cause cavitation, unstable flow, noise, and pump damage.

Can this replace a pump curve?

No. This calculator gives a planning duty point. Always compare the design flow and head with the manufacturer pump curve before buying or installing equipment.

Should I add a safety factor?

Yes. Construction sites often have changing loads, hose changes, cold starts, added fittings, and uncertain fuel demand. A safety factor improves practical reliability.