NFPA in USA

NFPA 72 calculator

Strobe Candela Coverage Calculator

Screen room dimensions against listed strobe candela coverage for early fire alarm layout checks.

Fire Alarm SystemsNFPA 72Workpaper

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

Room area

600 ft²

Calculated output

Room diagonal

36.06 ft

Calculated output

Representative max room size

43.3 ft

Calculated output

Room area600ft²
Room diagonal36.06ft
Representative max room size43.3ft
Coverage screenPass

NFPA in USA calculation workpaper

Strobe Candela Coverage Calculator

NFPA 72 · Fire Alarm Systems

nfpainusa.comGenerated record

Project record

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

Inputs

Room length
30 ft
Room width
20 ft
Listed candela
75

Results

Room area
600 ft²
Room diagonal
36.06 ft
Representative max room size
43.3 ft
Coverage screen
Pass

Calculation basis

Formula
Representative coverage screen from room dimensions and listed candela
Reference standard
NFPA 72
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

Representative coverage screen from room dimensions and listed candela

Copper Wire Resistance

Wire SizeOhms per 1000 ft
12 AWG1.588
14 AWG2.525
16 AWG4.016
18 AWG6.385
20 AWG10.15
22 AWG16.14

Use this result

Use coverage screen to flag whether selected candela needs layout or listing review.

Check before use
Confirm room dimensions and listed candela are for the same notification appliance scenario.
Common pitfall
A room-area screen cannot replace placement, mounting height, or listed coverage tables.
Next step
NAC Circuit Load Calculator

Input evidence

Confirm these values before using the result.

  • Room length (ft)
  • Room width (ft)
  • Listed candela

Authority basis

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

AHJ Contact ChecklistFire Protection Submittal 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

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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

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FAQ

What is this Strobe Candela Coverage 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.