Square Fire water tank NFPA 22

Application: Static fire water tank – fire department drafting (truck suction)
Location: Houston-area climate (rare freeze events)
System Type: No sprinkler system, no fixed fire pump
Minimum Usable Volume: 83,300 L (22,000 US gallons)

1. Purpose / Use

  • The tank shall serve as a static fire water storage tank.

  • In the event of a fire, a fire department pump truck will park adjacent to the tank and draft water directly from the tank.

  • There is no sprinkler system connected to this tank.

  • There is no permanently installed fire pump connected to this tank.

  • The tank shall be dedicated exclusively to fire protection use.

  • No domestic, irrigation, process, or makeup water connections are permitted.

2. Applicable Standards

The tank design, construction, and appurtenances shall explicitly comply with the following standards:

  • NFPA 22 – Water Tanks for Private Fire Protection

  • NFPA 1142 – Water Supplies for Suburban and Rural Fire Fighting

Requirements:

  • The edition year of each standard shall be clearly stated on all drawings.

  • “Designed with reference to” or “NFPA considered” language is not acceptable.

  • Compliance shall be explicit and complete.

3. Tank Geometry, Orientation & Layout (MANDATORY)

  • Tank internal geometry:

    • Length (East–West): 8.0 m (26.2 ft)

    • Width (North–South): 4.0 m (13.1 ft)

    • Water height: 3.0 m (9.8 ft)

  • Tank orientation:

    • The 8.0 m dimension shall run East–West

    • The 4.0 m dimension shall run North–South

  • Minimum usable volume shall be achieved within these dimensions.

4. Tank Construction

  • Tank construction type:

    • PLEASE QUOTE FOR:

      • Carbon Galvanized Steel (bolted/panelized)

      • Stainless Steel (bolted/panelized)

      • Fiberglass (bolted/panelized)

  • Square / rectangular tanks are permitted, provided they are fully structurally engineered.

  • Tank shall be designed for:

    • Full hydrostatic load

    • Empty condition uplift

    • Wind loads

    • Seismic loads in accordance with IBC / ASCE 7

  • Structural calculations shall be provided and sealed by a Professional Engineer.

  • Materials shall be clearly specified:

    • Plate thickness

    • Bolt size and grade (if bolted)

    • Gaskets

    • Interior liner or coating system

5. Foundation & Anchorage

  • A designed foundation or slab shall be provided.

  • Anchorage shall be designed for:

    • Sliding

    • Overturning

    • Uplift

  • Soil bearing assumptions shall be stated.

  • Tank-to-foundation interface shall be fully detailed.

6. Water Capacity

  • Total geometric volume shall be stated.

  • Usable fire water volume shall be clearly defined.

  • Minimum operating water level shall be identified.

  • Low water level shall not impair drafting or suction.

  • Volume shall be consistent with NFPA 1142 fire flow duration requirements.

7. Suction Outlet (CRITICAL REQUIREMENT)

  • A dedicated fire department suction outlet shall be provided.

  • Outlet size:

    • 6-inch (150 mm) female NST (National Standard Thread)

  • Outlet location:

    • Installed on the south side of the tank

    • Located approximately at the center of the south wall

  • Outlet arrangement shall:

    • Be suitable for fire department drafting

    • Be protected from physical damage

  • Outlet piping:

    • Rigid steel

    • Internally supported

    • Provided with debris protection (strainer or screen)

8. Anti-Vortex Provisions (MANDATORY)

The tank shall include explicit anti-vortex provisions in accordance with NFPA 22.

  • Acceptable devices include:

    • Vortex plate

    • Tee arrangement

    • Elbow diffuser

    • Perforated plate

  • Minimum water submergence shall be dimensioned on drawings.

  • Anti-vortex geometry shall be shown in detail.

  • Statements such as “no vortex expected” are not acceptable without geometry.

9. Fire Department Access

  • Tank shall be located within 15 ft (4.6 m) of a fire lane.

  • Fire apparatus shall be able to:

    • Park

    • Connect

    • Draft without obstruction

  • Suction connection height shall be usable by fire department apparatus.

  • Connection shall be clearly visible and accessible.

10. Venting

  • Atmospheric vent shall be provided.

  • Vent shall be sized to:

    • Prevent vacuum during drafting

    • Prevent overpressure during filling

  • Vent shall be protected with:

    • Screen

    • Weather hood

  • Vent shall be designed to resist blockage from debris or freezing.

11. Overflow

  • Overflow piping shall be provided.

  • Overflow shall be sized for the maximum fill rate.

  • Overflow discharge shall route to a safe location.

  • Overflow shall not flood the foundation or fire lane.

  • Overflow outlet shall be protected from blockage.

12. Drain

  • Tank drain shall be provided.

  • Drain valve shall be accessible and protected.

  • Drain discharge shall route to a safe location.

  • Drain shall not impair fire water availability.

  • Drain shall be protected from accidental operation or freezing.

13. Access & Inspection

  • Manway(s) shall be provided for internal access.

  • Manway size shall permit human entry.

  • Ladder:

    • External ladder shall be installed on the WEST side of the tank

  • Safe inspection access shall be provided.

  • Fall protection shall be included where required.

14. Roof / Cover

  • Tank shall include a roof or cover.

  • Roof shall prevent:

    • Debris entry

    • Animal entry

  • Roof shall be designed for:

    • Wind loads

    • Maintenance loads

  • All roof penetrations shall be sealed.

15. Corrosion Protection

  • Interior lining shall be compatible with stored fire water.

  • Exterior coating shall be suitable for Houston-area environmental exposure.

  • Dissimilar metals shall be addressed.

  • Corrosion allowance shall be stated.

16. Freeze Protection (Houston Climate)

  • Freeze protection strategy shall be defined, such as:

    • Insulation (NOT REQUIRED - DO NOT QUOTE)

    • Buried piping (NOT REQUIRED - DO NOT QUOTE)

    • Drainable suction piping

  • No reliance on continuous heating unless explicitly approved.

  • Fire department suction shall remain usable during rare freezing events.

17. Identification & Signage

  • Tank shall be permanently labeled “FIRE WATER”.

  • Water volume shall be posted if required by the AHJ.

  • Drafting instructions shall be provided if requested by the fire department.

  • Tank shall not be confused with any domestic water system.

18. Testing & Acceptance

  • Hydrostatic leak testing shall be performed.

  • Visual inspection shall be conducted.

  • Verification shall include:

    • Suction operation

    • Venting

    • Overflow

  • As-built drawings shall be provided.

19. Required Manufacturer Submittals

The manufacturer shall provide:

  • General arrangement drawings

  • Foundation Design/Drawing with loads

  • Structural calculations

  • Suction outlet details

  • Anti-vortex details

  • Vent and overflow sizing

  • Material specifications

  • Coating/liner data

  • Explicit written statement of compliance with NFPA 22 and NFPA 1142