FIRE-WATER PLANNING

Use the WTR Fire worksheet

Enter your name and email to estimate fire-water storage for your property. Freedom Rainwater can help with the next steps.

Questions? Call 512-560-8412

1Site address and AHJ

Street address

City

State

ZIP

Find a likely fire service area by address, your location at the property, or a map pin. Confirm the reviewing AHJ directly.

Confirmed reviewing fire department / AHJ

An ESD service area is a geographic clue, not proof of which office reviews or approves the water-supply plan. Type the reviewing department or fire marshal after confirming it. No NFPA factors are filled from an address.

Fire-water calculation worksheet

Follow the familiar footprint → volume → factors → gallons sequence.

NFPA 1142 · 2022 / 2027

For structural firefighting planning. A qualified person and the local authority having jurisdiction (AHJ) must review classifications, site conditions, supply and delivery. This worksheet is not an approval or sprinkler-system demand calculation.

1Building footprint and volume

Length · ft

Width · ft

Footprint · ft² (calculated)Enter length and width

Wall / ceiling height · ft

Enter the enclosed wall height. Add half the pitched-roof rise below if its triangular attic volume is enclosed and was not counted here.

Pitched-roof rise · ft

Enter vertical rise from wall top to ridge. The worksheet adds half this rise to effective height for a simple pitched roof. Use 0 for a flat roof or no counted attic; confirm unusual geometry separately.

Other enclosed volume · ft³

Use for attached enclosed areas omitted from the footprint, such as a separately measured addition. Do not count open porches as enclosed volume without a qualified determination.

Main enclosed volume—

Roof + attached volume—

Total enclosed volume · ft³—

2Occupancy hazard classification

Edition used by AHJ

Ask the department which NFPA 1142 edition it applies locally. The 2022 and 2027 editions classify dwellings and parking garages differently.

Building use

Selecting a dwelling or automobile parking garage fills in the edition-specific class. For mixed or unusual uses, select Other and enter the most hazardous applicable class after review.

Occupancy hazard class · required

NFPA 1142 Chapter 5 examples
3 · Severe: sawmills, flour mills, flammable-liquid spraying.
4 · High: commercial barns, warehouses, repair garages.
5 · Moderate: restaurants, machine shops, farm equipment sheds. Combustible storage cannot exceed 12 ft for this class.
6 · Low: churches, doctors’ offices. Dwellings are class 6 in 2027; parking garages are class 6 in 2022.
7 · Light: offices, schools. Dwellings are class 7 in 2022.
For mixed uses, the most hazardous applicable class (lowest number) governs the whole building. Contents can change the answer; choose “I don’t know” when unsure.

Use / contents

Choose Dwelling or Parking garage above to fill this class automatically. For other uses, select the documented class here; use “I don’t know” if it needs professional review.

Enclosed volume ÷ OHC—

3Construction classification

Construction type

NFPA 1142 Chapter 6 overview
Type I · 0.5: fire-resistive structure with qualifying noncombustible or limited-combustible structural elements and ratings.
Type II · 0.75: qualifying noncombustible structure; examples can include steel or concrete construction, depending on assembly and ratings.
Type III · 1.0: qualifying noncombustible exterior walls with some combustible interior framing; often called ordinary construction.
Type IV · 0.75: qualifying heavy timber with required member sizes and wall construction.
Type V · 1.5: wood-frame or other combustible structure, such as many frame buildings.
A brick veneer or metal siding alone does not establish a type. Confirm the structural assemblies and fire-resistance ratings from plans. Mixed construction uses the highest applicable factor. In 2022, a dwelling’s factor is capped at 1.0.

CC multiplier (calculated)Choose construction type

After construction multiplier—

4Exposure and suppression

Qualifying unattached exposure?

A building within 50 ft qualifies if at least 100 ft², or any size if hazard class 3 or 4 (§4.1.5). Count the exposure multiplier once, not once per building. Confirm attached spaces separately.

Automatic suppression

Fully compliant NFPA 13/13D/13R may allow an AHJ-approved manual supply reduction, but none is automatic. Other systems require AHJ determination (§§4.4–4.5).

Shared source serves other structures?

Dimensions and classifications checked?

Exposure multiplier—

Applicable Chapter 4 minimum—

5Water requirement and delivery

Preliminary structural firefighting supply · NFPA 1142 Chapter 4Pending inputs

Enter the worksheet fields above.

Table 4.6.1 delivery ratePending

Gallons ÷ delivery rate · indicative minutes—

Additional water supply · worksheet option

“In accordance with NFPA 1403, an additional water supply in the amount of 50% of total required fire flow must be available to handle unforeseen situations.”

Some fire-department worksheets add 50% after calculating the NFPA 1142 supply and attribute it to NFPA 1403. That is a separate reserve, not the NFPA 1142 exposure factor. NFPA 1403 applies to live-fire training; a blanket requirement for ordinary building supply has not been verified. Confirm this extra reserve with the reviewing department. If an AHJ-entered gallon amount already includes it, leave this off to avoid counting it twice.

Worksheet attribution only. Confirm whether your AHJ applies this additional reserve to this project; NFPA 1403 addresses live-fire training.

Optional reserve · 50% of sizing baseOff

Tank sizing target including selected reservePending

The sizing base is the Chapter 4 result, or the separately entered AHJ gallon amount. The optional reserve changes tank recommendations, not the Chapter 4 result or its delivery-rate lookup.

The calculated quantity is not the usable water guaranteed by a tank. Outlet height, draw-off, fittings and delivery need separate design review. Whole gallons are rounded up for planning; the AHJ must confirm the rounding convention.

Project and AHJ record

Project name

Using worksheet as

Organization / department (professional document heading)

Contact

Phone

Reviewer status

Reviewer name

AHJ-established gallons, if different

Keep an AHJ-established value distinct from the worksheet calculation. Enter only a written determination; include the reason below.

AHJ delivery rate · gpm

Local criteria / reason for AHJ revision

Existing verified water source

Exposures, other structures, special hazards and geometry notes

Department comments / next steps

Fire tank builder

The builder shows the smallest XLE and smallest flat panel configuration that meet the worksheet target for your chosen tank count. Final usable volume depends on the outlet and site design.

Required usable water for planningPending

Listed net usable capacities assume 6 in. below an anti-vortex plate and 6 in. of freeboard (manufacturer's low seismic risk basis). Confirm the actual outlet elevation, draw-off, seismic design, and available volume before acceptance. The worksheet's delivery rate must be achievable at the fire department connection.

Tank family

Number of matching tanks

Choose	Model	Nominal gal / tank	Listed usable gal / tank*	Diameter × height	Concrete pad diameter	Capacity check

Selected configuration

Select a model to create the configuration schedule.

Base kit and design checks

Choose a model above.

Required calculation inputs: Delivery rate pending. Connection and accessory code review: Requires verified NFPA source for the locally adopted edition. Ask the AHJ to specify fittings, location, access and water delivery arrangement before design approval.

Department choices and optional equipment

Select components only when confirmed by the fire department or the project designer. Select the hard suction hose and storage details requested by the fire department.

Fire outlet / anti-vortex fitting

Outlet valve

Fire department connection

Refill / fill equipment

Level indication

Access ladder

Hard suction hose and storage

Drawings / engineering

Additional AHJ requirements / connection schedule

No pricing is published. The PDF is a concept package for review; it is not a final installed proposal or AHJ approval.

Records saved on this device

Local preview only: records are not shared with Freedom, a department, or another device. Export for backup. Admin authentication and shared database are not yet connected.

Project	Contact	AHJ	Status	Saved

Saved worksheets stay on this device only. Export a CSV if you need a backup or want to move records to another system.

Annual fire tank inspection

Track the due date for each fire tank, request a visit, and keep inspection reports and fire department submission records together.

Due dates follow the schedule recorded for your site. Freedom can confirm your department's requirements. A due date is separate from a confirmed appointment.

Open your inspection records

Verify your email to protect your property records and reports.

Open inspection records in a separate window

Freedom inspection management

Preliminary Fire-Water Storage Calculation Sheet

WTR Fire · Powered by Freedom Fire Tanks · For AHJ review, not approval

Department comments: _________________________________________________________________

Reviewer / date: _____________________________________________________________________

Conceptual and preliminary. The AHJ controls local criteria and acceptance. Drawings require site-specific engineering and review.