Hazard Classification NFPA 13

NFPA 13 light, ordinary and extra hazard: density, remote area, storage.

Occupancy hazard classification per NFPA 13, with the design parameters that follow from it: density, remote area, hose allowance and duration.

WHAT IT CALCULATES
- Hazard class from occupancy type, or set the class by hand
- Light hazard: 0.10 gpm per sq ft over 1500 sq ft, 100 gpm hose, 30 minutes
- Ordinary Group 1: 0.15 gpm per sq ft over 1500 sq ft, 250 gpm hose, 60 minutes
- Ordinary Group 2: 0.20 gpm per sq ft over 1500 sq ft, 250 gpm hose, 60 minutes
- Extra Group 1: 0.30 gpm per sq ft over 2500 sq ft, 500 gpm hose, 90 minutes
- Extra Group 2: 0.40 gpm per sq ft over 2500 sq ft, 500 gpm hose, 90 minutes
- Estimated system demand from the density and area you end up with

CODE REFERENCES BUILT IN
- NFPA 13 sections 5.2 through 5.4 - occupancy classification
- NFPA 13 Annex A.5.3 and A.5.4 - the examples that decide Group 1 versus Group 2
- NFPA 13 Table 11.2.3.1.1 - design density and operating area

HOW IT WORKS
Choose the occupancy, or override the hazard class. You get the class, design density, remote area, hose allowance, duration and the resulting demand.

CORE FEATURES
- Works 100 percent offline, no signal needed on site
- Calculation history you can reopen and reuse
- PDF export for submittals and field records
- Light and dark themes
- English and Spanish
- Material Design 3 interface

TYPICAL USES
- Checking a layout on site before the pipe goes up
- Verifying a contractor submittal during plan review
- Sizing during a bid walk without pulling the code book out of the truck
- Backing a field decision with a PDF you can attach to the job file
- Studying for NICET certification

WHAT THE PDF REPORT INCLUDES
- Every input you entered
- The calculated results with units
- Date and time of the calculation

OPTIONAL PRO UPGRADE - $2.99 ONE-TIME IN-APP PURCHASE
The following features require a separate one-time in-app purchase. They are not required to use the calculator:
- Unlimited saved calculation history
- PDF export of results
- Dark theme
- Ad-free experience

WHO IT IS FOR
- Fire protection engineers and system designers
- Sprinkler fitters and installers
- Fire inspectors and AHJ plan reviewers
- Contractors preparing bids and submittals
- NICET candidates and fire protection students

ACCURACY NOTE
Results are a design aid, not a stamped design. Verify against the edition of the standard adopted in your jurisdiction and confirm with the authority having jurisdiction.

Part of FireTools, the fire protection calculator collection. More tools at tradetools.dev/fire