Fire Protection (C-16) · Lesson 2 of 6

Required Fire Flow: California Fire Code Appendix B

"Required Fire Flow: California Fire Code Appendix B" is lesson 2 of 6 in the Fire Protection (C-16) Learning Hub. It opens with "What Fire Flow Means in the Code" and works through 5 short steps, then a worked example you can check yourself against.

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Steps in this lesson

  1. What Fire Flow Means in the Code
  2. Find the Fire-Flow Calculation Area
  3. Read Table B105.1(2)
  4. Apply the Sprinkler Reduction (Table B105.2)
  5. Compare With the Sprinkler Demand (B105.3)

The worked example in the course applies this lesson to a realistic job in 5 steps, from "Find the calculation area" through "Check the Type IB alternative".

What you'll be able to do

  • Explain the main idea of "Required Fire Flow: California Fire Code Appendix B" in plain language you can use on the exam.
  • Apply this step with confidence: "Read Table B105.1(2)".
  • Apply this step with confidence: "Apply the Sprinkler Reduction (Table B105.2)".
  • Apply this step with confidence: "Compare With the Sprinkler Demand (B105.3)".
  • Test yourself on the worked example and the quick-check quiz inside the classroom.
Required Fire Flow: CFC Appendix BTABLE B105.1(2), TYPES IIB AND IIIBArea (sq ft)gpmhours70,601-77,0005,750477,001-83,7006,000483,701-90,6006,2504Calculation area (B104.1): 4 floors x 20,000= 80,000 sq ft, Type IIBFire flow is measured at 20 psi residual(B102.1). Type IA/IB would use only thethree largest successive floors (B104.1).NFPA 13 REDUCTION (TABLE B105.2)Table value: 6,000 gpm for 4 hr25% x 6,000 = 1,500 gpmFloor for 903.3.1.1 is 1,000 gpm: OKDuration at 1,500 gpm: 2 hrB105.3: supply must give the greater ofsprinkler demand with hose stream = 900required fire flow = 1,500 gpmGreater value governs:1,500 gpm at 20 psi, 2 hoursFire flow = Table B105.1(2) value, then x 25% (not less than 1,000 gpm) with an NFPA 13 systemWater supply = greater of fire flow and sprinkler demand with hose stream (B105.3)Supply: 1,500 gpm at 20 psi residual for 2 hoursUnsprinklered the same building needs 6,000 gpm for 4 hoursSource: 2025 CFC Appendix B (B102.1, B104.1, Tables B105.1(2) and B105.2, B105.3); CFC 507.3CC
The diagram for this lesson, exactly as it appears in the Learning Hub.

The first steps of this lesson

Step 1: What Fire Flow Means in the Code

CFC Section 507.3 says fire-flow requirements for buildings are determined by an approved method or by Appendix B. Appendix B defines fire flow as the flow rate of a water supply, measured at 20 psi residual pressure, that is available for firefighting (B102.1). It is a water supply number, separate from the sprinkler system design demand. The appendix is not mandatory unless the local ordinance adopts it, so confirm with the fire code official which method the city uses.

Step 2: Find the Fire-Flow Calculation Area

The fire-flow calculation area is the total floor area of all floor levels within the exterior walls and under the horizontal projections of the roof (B104.1). There are two exceptions: for Types IA and IB construction it is the area of the three largest successive floors, and for open parking garages of Types IA and IB it is the area of the largest floor. Portions of a building separated by fire walls without openings, built per the California Building Code, may be treated as separate calculation areas (B104.2).

The remaining 3 steps, the worked example and the quiz are in the course. This is a preview. The full lesson, with the step-by-step explanations, a worked example and a quick-check quiz, is inside the classroom.

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