NFPA in USA

Reference library

Fire protection reference tables

Structured lookup tables that support calculator setup and engineering checks.

C valuesK-factorsPipe dimensionsAWG resistanceHazard classes

Tables

8

Engineering lookup pages

Linked tools

30

Calculator library

Use

Setup

Inputs and screening checks

Page role

Use this page for a defined task before moving to the next project record.

Audience
Engineers, designers, reviewers, and technicians selecting calculator input values.
Job
Choose controlled lookup values before running a calculator or worksheet.
Evidence
Pipe material, K-factor, pipe schedule, fitting type, hazard class, AWG size, or field condition.
Output
A selected row or value retained with the calculation workpaper.
Next
Open the linked calculator that consumes the selected reference value.

How reference tables support the calculators

Use these tables to select C values, K-factors, internal pipe diameters, equivalent fitting lengths, density and area baselines, AWG resistance, and hazard classes before running a calculator.

Choose the controlled input table

Pick the reference table by the input field you are about to carry into a calculator or worksheet.

Reference tableControlled fieldUse whenDownstream useOpen

Hazen-Williams C Values for Fire Sprinkler Pipe

Hazen-Williams C values pipe

Pipe Material / C ValueUse this table when a sprinkler hydraulic check needs a C value tied to pipe material, condition, and wet or dry system context.Hazen-Williams Sprinkler Friction Loss Calculator, Sprinkler System Demand Calculator, NFPA 13 Hydraulic Design WorksheetOpen table

Fire Sprinkler K-Factor Table

sprinkler K-factor table

K-Factor / Typical UseUse this table when a sprinkler discharge check needs the listed K-factor before solving flow, pressure, or minimum flow.Sprinkler K-Factor Flow and Pressure Calculator, Sprinkler System Demand Calculator, NFPA 13 Hydraulic Design WorksheetOpen table

Sprinkler Pipe Internal Diameter Reference

pipe internal diameter schedule 10 40

Nominal Size / Schedule 10 ID (in)Use this table when a calculator needs internal diameter rather than nominal pipe size.Hazen-Williams Sprinkler Friction Loss Calculator, Sprinkler Pipe Velocity Calculator, NFPA 13 Hydraulic Design WorksheetOpen table

Equivalent Pipe Lengths for Common Fittings

equivalent pipe length fittings NFPA 13

Pipe Size / FittingUse this table when fittings need to be added to straight pipe length for a preliminary sprinkler friction-loss screen.Equivalent Length Calculator for Sprinkler Fittings, Hazen-Williams Sprinkler Friction Loss Calculator, NFPA 13 Hydraulic Design WorksheetOpen table

NFPA 13 Design Density and Area Reference

NFPA 13 density area curve

Hazard Classification / Density (GPM/sq ft)Use this table when a preliminary hazard class needs a paired density and design-area basis for demand screening.NFPA 13 Density and Area Demand Calculator, Design Density Lookup Calculator, Hazard Classification and Density Setup WorksheetOpen table

AWG Wire Resistance Table for Fire Alarm Circuits

AWG wire resistance table

Wire Size / Ohms per 1000 ftUse this table when fire alarm voltage drop or circuit resistance needs conductor resistance by AWG size.Fire Alarm NAC Voltage Drop Calculator, Fire Alarm Wire Resistance Calculator, Fire Alarm Battery and NAC WorksheetOpen table

Occupancy Hazard Classification Reference

NFPA 13 occupancy hazard classification

Occupancy / Likely Hazard ClassUse this table to screen common occupancy examples before selecting a preliminary sprinkler hazard class.Occupancy Hazard Classifier Calculator, Design Density Lookup Calculator, Hazard Classification and Density Setup WorksheetOpen table

US Code Adoption and AHJ Checkpoints

US fire code adoption AHJ checklist

Checkpoint / Why It MattersUse this checklist at project intake before relying on any NFPA calculator, worksheet, or reference table.Sprinkler System Demand Calculator, Fire Alarm Battery Capacity Calculator, Occupancy Hazard Classifier CalculatorOpen table

Tables

Reference tableLookup purposeUsed byOpen

Hazen-Williams C Values for Fire Sprinkler Pipe

Hazen-Williams C values pipe

Lookup common Hazen-Williams roughness coefficients for steel, copper, CPVC, cast iron, and dry-system sprinkler pipe materials.2 linked calculatorsOpen

Fire Sprinkler K-Factor Table

sprinkler K-factor table

Reference common sprinkler K-factor values used for quick flow and pressure checks in NFPA 13 style sprinkler calculations.2 linked calculatorsOpen

Sprinkler Pipe Internal Diameter Reference

pipe internal diameter schedule 10 40

Compare typical Schedule 10 and Schedule 40 internal pipe diameters used in sprinkler hydraulic and velocity calculations.2 linked calculatorsOpen

Equivalent Pipe Lengths for Common Fittings

equivalent pipe length fittings NFPA 13

Reference common equivalent length allowances for fittings when estimating sprinkler pipe friction loss and remote-area demand.2 linked calculatorsOpen

NFPA 13 Design Density and Area Reference

NFPA 13 density area curve

Lookup common density and design-area combinations for light, ordinary, and extra hazard sprinkler design screening.2 linked calculatorsOpen

AWG Wire Resistance Table for Fire Alarm Circuits

AWG wire resistance table

Lookup copper conductor resistance values for fire alarm NAC and SLC voltage drop calculations using common AWG sizes.2 linked calculatorsOpen

Occupancy Hazard Classification Reference

NFPA 13 occupancy hazard classification

Screen common occupancy examples against broad NFPA 13 hazard classes for early sprinkler design scoping and calculator setup.2 linked calculatorsOpen

US Code Adoption and AHJ Checkpoints

US fire code adoption AHJ checklist

Use this jurisdiction checklist before applying NFPA calculators on a United States project because adopted editions, local amendments, and AHJ direction can vary.3 linked calculatorsOpen