Stop Over‑Designing Your Firewater Tanks!

Stop Over‑Designing Your Firewater Tanks!

SBC 801 (2024) is the latest Saudi Building Code for Fire Protection and Life Safety, aligning with the International Fire Code (2021). It defines the master fire‑flow calculation standard used to size firewater tanks, pumps, and hydrant networks.

🔥 Core Fire‑Flow Requirements

Parameter	SBC 801 (2024) Requirement	Notes
Minimum Hydrant Flow	1 000 GPM (3 785 L/min) for ordinary hazard; 1 500 GPM (5 678 L/min) for high‑hazard or sprinklered buildings	Based on hazard classification and sprinkler protection
Duration of Fire Flow	2–4 hours	Depends on occupancy and risk level
Flow Pressure at Hydrant	≥ 138 kPa (20 psi) during operation	Must be maintained at all hydrants
Hydrant Spacing	90–150 m (300–500 ft) apart	Reduced by 30 m (100 ft) on dead‑end streets
Maximum Distance to Hydrant	≤ 75 m (250 ft) from any point on property	Ensures full coverage
Minimum Pipe Size	150 mm (6 in)	For adequate flow and pressure
Accessibility Clearance	≥ 900 mm (3 ft) around hydrant	No obstructions for fire apparatus

🔹 Key Inputs

• Hazard Classification → Light, Ordinary, Extra Hazard.

• Required Hydrant Flow → 1 000–1 500 GPM depending on risk.

• Duration → 2–4 hours based on occupancy.

• Pressure Requirement → ≥ 20 psi at most remote hydrant.

• Sprinkler & Hose Reel Allowance → Added to hydrant demand.

🧮 Master Fire‑Flow Calculation Workflow

1. Identify Building Hazard Category (Light, Ordinary, Extra).

2. Determine Required Flow (Q):

   • $Q=\text{Hydrant Flow}+\text{Sprinkler Demand}+\text{Hose Reel Allowance}$

3. Establish Duration (t):

   • From SBC 801 Table D‑1 (typically 2–4 h).

4. Compute Storage Volume (V):

$$V=Q\times t$$

5. Add Reserve (10–15 %) for pump priming and evaporation.

6. Verify Pressure & Velocity:

   • Maintain 20 psi minimum at most remote hydrant.

7. Hydraulic Modeling:

   • Confirm simultaneous hydrant operation under peak demand.

🧯 Integration with SBC 201 (2024)

• Fire Apparatus Access Roads: Appendix D revised — aerial access not required for fully sprinklered Type IA–IIA buildings.

• Fire Pump & Riser Rooms: Must have permanent illumination and adequate clearance.

• Automatic Sprinklers: Mandatory for open parking areas > 4 460 m².

🔹 Workflow Steps

1. Identify hazard category.

2. Determine hydrant flow demand.

3. Add sprinkler and hose reel demand.

4. Apply duration requirement.

5. Compute total tank volume.

6. Add 10–15% reserve.

⚙️ Design Tips for Compliance

• Use NFPA 13, 14, 20, 22 cross‑references for hydraulic validation.

• Avoid over‑designing firewater tanks — base capacity on actual flow duration.

• Employ BIM‑based hydraulic modeling for coordination and clash detection.

• Obtain Civil Defense approval for deviations or special hazard designs.

✅ Key Takeaway: Under SBC 801 (2024), the master fire‑flow standard ensures that hydrant networks deliver 1 000–1 500 GPM for 2–4 hours at ≥ 20 psi, with spacing and accessibility optimized for firefighting efficiency. Correct application prevents oversized tanks and pumps, achieving cost‑effective, code‑compliant fire protection.