NFPA in USA

NFPA 25 calculator

Water Supply Curve Plotter

Create tabular water supply curve points from static, residual, and flow test data.

Water Supply AnalysisNFPA 25Workpaper

Calculation workpaper

Enter inputs, review outputs, then use the guidance below before carrying the result forward.

US customary units

Calculation inputs

Enter project screening values in the units shown.

Ready

Worksheet header

Optional project fields for keeping the calculation screen traceable.

Results

Ready

Available flow

1,809.9 GPM

Calculated output

Static pressure

80 psi

Calculated output

Residual pressure

60 psi

Calculated output

Available flow1,809.9GPM
Static pressure80psi
Residual pressure60psi
Required residual20psi
Pressure drop20psi
Supply curve point1809.9 GPM at 20 psi

NFPA in USA calculation workpaper

Water Supply Curve Plotter

NFPA 25 ยท Water Supply Analysis

nfpainusa.comGenerated record

Project record

Project ID
Not entered
Area
Not entered
System
Not entered
Revision
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Prepared by
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Checked by
Not entered

Inputs

Measured test flow
1000 GPM
Static pressure
80 psi
Residual pressure
60 psi
Required residual
20 psi

Results

Available flow
1,809.9 GPM
Static pressure
80 psi
Residual pressure
60 psi
Required residual
20 psi
Pressure drop
20 psi
Supply curve point
1809.9 GPM at 20 psi

Calculation basis

Formula
Supply curve from hydrant flow test relationship
Reference standard
NFPA 25
Professional boundary
Verify adopted code, project criteria, listed equipment data, and AHJ requirements before relying on this record.
NFPA in USAnfpainusa.comThis is a calculation record, not a signed or sealed engineering document.

Calculation basis

Use the formula and linked reference data after the result is visible. Keep input selection separate from the calculation screen.

Formula

Supply curve from hydrant flow test relationship

Review note

Confirm units before comparing results. If the value controls a design choice, check it against adopted criteria and project-specific inputs.

Use this result

Use curve points to compare system demand against available water supply.

Check before use
Confirm the source test data is valid before using generated curve points.
Common pitfall
A curve generated from poor field data still looks precise but is not reliable.
Next step
Available Water Supply Calculator

Input evidence

Confirm these values before using the result.

  • Measured test flow (GPM)
  • Static pressure (psi)
  • Residual pressure (psi)
  • Required residual (psi)

Authority basis

Check jurisdiction, AHJ, submittal, and edition records before using this result as project evidence.

AHJ Contact ChecklistInspection and Testing Forms WorkflowNFPA 13, 72, and 25 Edition Basis Worksheet

Record retention

Save the PDF after project fields, inputs, and results are set.

PDF includes

  • Project header and calculator inputs
  • Computed result rows and warnings
  • Formula, reference basis, and professional boundary

Check before filing

  • Input traceability
  • Method review
  • Output reasonableness
  • Professional boundary

Open next

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Engineering disclaimer
NFPA in USA provides engineering workpapers, calculation checks, and reference tables for project screening and coordination. Final design decisions, code interpretations, submittals, and acceptance records must be completed by qualified professionals and verified against the adopted code, project criteria, listings, and Authority Having Jurisdiction requirements. This site does not issue signed or sealed engineering documents.

Related tools and tables

Hydrant Flow Test CalculatorNFPA 25 tool hub

FAQ

What is this Water Supply Curve Plotter calculator for?+
Use it to compute a defined fire protection value from documented inputs, then retain the inputs, result, formula, and warnings with the project record.
Are the results suitable for permit submission?+
Use the saved record only after it is checked against adopted code, project criteria, equipment listings, and AHJ requirements.