Diesel Fuel Calculator for Diesel Fire Pump Engine Applications
You need to plan every aspect of your pump room down to a tee. We’ve provided this helpful calculator so you can determine the correct diesel fire tank size, feed lines, and return pipe dimensions for your pump room — giving you the confidence that your fire protection system is properly configured.
Below you’ll be able to utilize a number of valuable resources, including:
- The Diesel Fuel Tank Sizing calculator, used to confirm the NFPA tank sizes recommended for each Clarke engine based on fuel consumption and run times.
- The Fuel Line Pipe Length and Diameter calculator, used to confirm the fuel supply and fuel return sizes based on the Clarke engine selection and customer provided schedule 40 pipe lengths and the number of elbows used.
- An NFPA-Compliant Fuel System Layout of our fire pump fuel system and requirement
Make data-driven decisions that will ensure your fuel pump’s success!


FUEL TANK - RESULTS
Customer:
Job Name:
Job Number:
TANK INFORMATION
ENGINE DATA
Engine Model:
Engine Speed:
Rated Power:
NFPA SIZES prior to 2022
Fuel Consumption:
NFPA Min. Tank Size:
NFPA Min. Run Time:
NFPA SIZES per 2022
Fuel Consumption:
NFPA Min. Tank Size:
NFPA Min. Run Time:
12 Hours
REFERENCES
Size for 8 Hour Run Time:
ACTUAL SIZE
Actual Tank Size:
Actual Run Time:
FUEL TANK LAYOUT

NOTES:
- Per NFPA20 2022 11.4.1.3.1 Fuel supply tank(s) shall be sized for a minimum of 12 hours of engine run time based on the fuel supply rate requirements of the engine, plus 5% volume for expansion and 5% volume for sump.
- Per NFPA20 2022 11.4.1.3.1.1 When the fuel supply rate requirements of the engine are not known, fuel supply tank(s) shall have a capacity at least equal to 1 Gal/HP (5.07L/kW), plus 5% volume for expansion and 5% volume for sump.
- NFPA Tank Run Time = Listed Power ÷ Fuel Consumption
- Min. Size for 12 Hour Run Time = Fuel Consumption x 12 hours x 1.1
- Min. Size for 8 Hour Run Time = Fuel Consumption x 8 hours x 1.1
- Actual Tank Runtime = Actual Tank Size x 0.9 ÷ Fuel Consumption
- The fuel tank outlet shall not be lower than the fuel transfer pump
- Refer to the latest edition of NFPA 20 for all fuel tank and fuel line requirements
North American Office:
100 Progress Place � Cincinnati, OH � 45246 � USA � Tel: +1 (513) 475-3473
European Office:
Grange Works � Lomond Road � Coatbridge, Scotland � ML5 2NN � Tel: +44 (0) 1236 429 946 � Fax: +44 (0) 1236 427 274