T ypes of Firefighting systems: 1. Wet Pipe Sprinkler System Description: Most common type. Pipes are always filled with pressurized water. Sprinklers activate individually during a fire. 📘 NFPA Standard: NFPA 13 – Standard for the Installation of Sprinkler Systems ✅ Pros: Simple, reliable, quick response. ⚠️ Cons: Not suitable for freezing environments. 2. Dry Pipe Sprinkler System Description: Pipes are filled with pressurized air or nitrogen. When a sprinkler head opens, air escapes, then water flows in. 📘 NFPA Standard: NFPA 13 ✅ Pros: Suitable for cold or freezing areas. ⚠️ Cons: Slight delay in water discharge. 3. Pre-Action Sprinkler System Description: Similar to dry pipe but includes a detection system (e.g. smoke/heat). Water fills the pipes only after detection and confirmation. 📘 NFPA Standard: NFPA 13 NFPA 72 – National Fire Alarm and Signaling Code ✅ Pros: Ideal for high-value assets like data centers, museums. ⚠️ Cons: More complex and expensive. 4. Deluge Syste...
Gul Bahar Shah
Gul Bahar Shah
Practical Design Calculation Framework (NFPA 11 & NFPA 16)
1️⃣ Define the Hazard & Protection Method
Typical Hazards
• Fuel storage tanks
• Pump rooms
• Aircraft hangars
• Loading racks
• Dike areas
• Process units
Foam System Types
System Standard Typical Use
Low-Expansion Foam NFPA 11 Tank farms, diked areas
Foam-Water Sprinkler NFPA 16 Hangars, pump rooms
Foam-Water Deluge NFPA 16 Process areas
👉 Example Used Below:
Low-Expansion Foam System protecting a hydrocarbon spill area
2️⃣ Select Foam Concentrate Type
Foam Type Application
AFFF Hydrocarbon fuels
AR-AFFF Polar solvents
Protein / Fluor protein Fixed tank systems
👉 Example: 3% AFFF
3️⃣ Determine Design Application Rate
From NFPA 11 (Hydrocarbon spills):
Protection Application Rate
Spill / Diked Area 6.5 L/min/m²
Tank Shell Protection 4.1 L/min/m²
Aircraft Hangar 6.5–8.1 L/min/m²
4️⃣ Determine Protected Area
Example:
• Diked spill area = 400 m²
5️⃣ Calculate Required Foam Solution Flow
Formula
Q_s = A \times R
Where:
• Q_s = foam solution flow (L/min)
• A = area (m²)
• R = application rate (L/min/m²)
Example
Q_s = 400 \times 6.5 = 2600 \text{ L/min}
✅ Required foam solution flow = 2600 L/min
6️⃣ Calculate Foam Concentrate Flow Rate
Q_f = Q_s \times \text{Foam Concentration}
For 3% foam:
Q_f = 2600 \times 0.03 = 78 \text{ L/min}
7️⃣ Calculate Water Flow Rate
Q_w = Q_s - Q_f
Q_w = 2600 - 78 = 2522 \text{L/min}
8️⃣ Determine System Discharge Devices
Typical Options
• Foam makers
• Foam chambers
• Foam sprinklers
• Foam monitors
Assume:
• Each foam maker = 500 L/min
N = \frac {2600}{500} = 5.2 \approx. 6 \text{foam makers}
9️⃣ Hydraulic Pressure Requirements
Typical Minimum Pressures
Device Pressure
Foam sprinkler 1.4–2 bar
Foam maker 2.8–3.5 bar
Foam chamber 3.5 bar
Example:
• Device pressure = 3.0 bar
• Pipe friction = 2.0 bar
• Elevation loss = 1.0 bar
• Safety margin = 1.0 bar
P_{total} = 3.0 + 2.0 + 1.0 + 1.0 = 7.0 \text{bar}
🔟 Foam Proportioning Method
Method Application
Bladder Tank Fixed installations
Balanced Pressure Large systems
Inline Inductor Small systems
Around-the-Pump Retrofit
👉 Example: Bladder tank proportioner (3%)
1️⃣1️⃣ Foam Solution Discharge Duration
From NFPA 11 (Hydrocarbon spill):
• Minimum = 15 minutes
V_s = Q_s \times t
V_s = 2600 \times 15 = 39,000 \text{L}
1️⃣2️⃣ Foam Concentrate Storage Volume
V_f = V_s \times 0.03
V_f = 39,000 \times 0.03 = 1,170 \text{L}
👉 Provide minimum 1,200 L foam concentrate (rounded)
1️⃣3️⃣ Fire Pump Sizing
Pump must satisfy:
• Flow ≥ 2600 L/min
• Pressure ≥ 7 bar
Typical selection:
🔥 3000 L/min @ 8 bar fire pump
Typical Hazards
• Fuel storage tanks
• Pump rooms
• Aircraft hangars
• Loading racks
• Dike areas
• Process units
Foam System Types
System Standard Typical Use
Low-Expansion Foam NFPA 11 Tank farms, diked areas
Foam-Water Sprinkler NFPA 16 Hangars, pump rooms
Foam-Water Deluge NFPA 16 Process areas
👉 Example Used Below:
Low-Expansion Foam System protecting a hydrocarbon spill area
2️⃣ Select Foam Concentrate Type
Foam Type Application
AFFF Hydrocarbon fuels
AR-AFFF Polar solvents
Protein / Fluor protein Fixed tank systems
👉 Example: 3% AFFF
3️⃣ Determine Design Application Rate
From NFPA 11 (Hydrocarbon spills):
Protection Application Rate
Spill / Diked Area 6.5 L/min/m²
Tank Shell Protection 4.1 L/min/m²
Aircraft Hangar 6.5–8.1 L/min/m²
4️⃣ Determine Protected Area
Example:
• Diked spill area = 400 m²
5️⃣ Calculate Required Foam Solution Flow
Formula
Q_s = A \times R
Where:
• Q_s = foam solution flow (L/min)
• A = area (m²)
• R = application rate (L/min/m²)
Example
Q_s = 400 \times 6.5 = 2600 \text{ L/min}
✅ Required foam solution flow = 2600 L/min
6️⃣ Calculate Foam Concentrate Flow Rate
Q_f = Q_s \times \text{Foam Concentration}
For 3% foam:
Q_f = 2600 \times 0.03 = 78 \text{ L/min}
7️⃣ Calculate Water Flow Rate
Q_w = Q_s - Q_f
Q_w = 2600 - 78 = 2522 \text{L/min}
8️⃣ Determine System Discharge Devices
Typical Options
• Foam makers
• Foam chambers
• Foam sprinklers
• Foam monitors
Assume:
• Each foam maker = 500 L/min
N = \frac {2600}{500} = 5.2 \approx. 6 \text{foam makers}
9️⃣ Hydraulic Pressure Requirements
Typical Minimum Pressures
Device Pressure
Foam sprinkler 1.4–2 bar
Foam maker 2.8–3.5 bar
Foam chamber 3.5 bar
Example:
• Device pressure = 3.0 bar
• Pipe friction = 2.0 bar
• Elevation loss = 1.0 bar
• Safety margin = 1.0 bar
P_{total} = 3.0 + 2.0 + 1.0 + 1.0 = 7.0 \text{bar}
🔟 Foam Proportioning Method
Method Application
Bladder Tank Fixed installations
Balanced Pressure Large systems
Inline Inductor Small systems
Around-the-Pump Retrofit
👉 Example: Bladder tank proportioner (3%)
1️⃣1️⃣ Foam Solution Discharge Duration
From NFPA 11 (Hydrocarbon spill):
• Minimum = 15 minutes
V_s = Q_s \times t
V_s = 2600 \times 15 = 39,000 \text{L}
1️⃣2️⃣ Foam Concentrate Storage Volume
V_f = V_s \times 0.03
V_f = 39,000 \times 0.03 = 1,170 \text{L}
👉 Provide minimum 1,200 L foam concentrate (rounded)
1️⃣3️⃣ Fire Pump Sizing
Pump must satisfy:
• Flow ≥ 2600 L/min
• Pressure ≥ 7 bar
Typical selection:
🔥 3000 L/min @ 8 bar fire pump
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