Calculation sequence
Step-by-step method
- Confirm the calculation boundary, units, and source of every input.
- Apply the displayed equation to the entered values.
- Review the result against governing criteria and documented uncertainty.
PlumbingBeginnerLiquid Fuels
Fuel-Oil Day-Tank Runtime Calculator
Calculate constant-demand runtime from tank volume, usable fraction, reserve fraction, and fuel demand.
Why it matters: A transparent formula keeps the user-entered hydraulic, gas, or storage basis available for technical review.
Calculated result
Engineering evaluation
Fuel day-tank runtime (t_f)17.5 h
- Available fuel volume (V_a)
- 350 gal
Engineering interpretation
The entered usable range above reserve supports 17.5 hours at constant demand.
Important limitations
- Constant-consumption inventory screen only. Transfer-pump operation, return flow, expansion, low-level controls, code volume, fire protection, spill containment, and emergency reserve policy are separate.
Engineering knowledge center
Understand the calculation—not just the answer
Governing relationships
V_a=V_t(F_u−F_r)
t_f=V_a/q_f
Current substitution
V_a=500×(0.9−0.2)=350; t_f=350/20=17.5 h.
Equation legend
Inputs and calculated quantities
- V_t
- Tank volume — gal or L
- F_u
- Usable volume fraction — 0–1
- F_r
- Reserved volume fraction — 0–1
- q_f
- Constant fuel demand — gal/h or L/h
- t_f
- Fuel day-tank runtime — h
- V_a
- Available fuel volume — gal
Applications
How this calculation is used
Building design
Screen a documented system relationship without embedding a protected design table.
Construction
Check submittal and field values using the same visible inputs.
Commissioning
Reconcile measured and scheduled conditions before professional disposition.
Quality controls
Assumptions and limitations
Assumptions
- Inputs describe one documented system boundary and compatible operating condition.
- All values use the displayed symbols and one consistent unit system.
Limitations
- This screen does not establish code compliance, final design, equipment selection, or acceptance.
- Adopted codes, local criteria, manufacturer data, uncertainty, and professional judgment remain controlling.
Field use
Verification procedure
- Identify the calculation boundary and source of each input.
- Record representative values with compatible pressure, temperature, flow, and time bases.
- Review the result against the adopted criteria, manufacturer data, and uncertainty.
Common engineering mistakes
- Mixing standard and actual gas volumes or gauge and absolute pressures.
- Treating an arithmetic screen as a code-sizing table or hidden acceptance criterion.
Technical basis
References and source standards
- International Plumbing CodeAdopted edition and local amendments govern; protected sizing tables are not reproduced.
- American Society of Plumbing EngineersPlumbing engineering-method context; verify licensed references and project criteria.
- NIST SI and Unit GuidanceUnit and dimensional-conversion basis.
Engineering calculation disclaimer
These engineering tools are provided for educational, preliminary evaluation, field verification, and commissioning support. Results depend on the accuracy of user-entered information and the assumptions stated for each calculation. Every colored status and comparison is a screening indicator only; project criteria, contract requirements, applicable codes, manufacturer instructions, measurement uncertainty, and authorized engineering judgment govern. The tools do not replace project-specific engineering analysis or the judgment of a licensed professional engineer.
Read the full use and limitation statement