Installation of Deluge and Special Hazard Systems
Chapter Introduction
This chapter covers the installation, commissioning, and verification of deluge systems and special hazard systems (foam, clean agent, CO₂, water mist). For the Red Seal exam, you must master the hydraulic principles, the fundamental differences from conventional systems, the requirements of NFPA 13, NFPA 15, NFPA 16, NFPA 11, NFPA 12, and NFPA 2001, as well as the installation specifics unique to each type of system.
Section 1: Definitions and Fundamental Principles
1.1 Deluge System — Definition
A deluge system is a dry-pipe sprinkler system in which the sprinkler heads are open (no bulb or fusible link). Water is held back upstream by a deluge valve that opens automatically when a detection device (smoke, heat, or flame detector) is activated. Water is then discharged simultaneously from all heads in the system.
Unlike a conventional system where only the head activated by heat opens, the deluge system floods the entire protected area. This characteristic makes it essential for rapidly spreading hazards: electrical transformers, flammable liquid storage tanks, tunnels, conveyors, etc.
1.2 Key Difference: Deluge Valve vs. Alarm Valve
| Characteristic | Deluge Valve | Alarm Valve (Wet System) |
|---|
| Heads | Open | Closed (bulb) |
| Water in piping | Absent upstream of valve | Present at all times |
| Activation | External detection | Fire heat |
| Discharge | All heads simultaneously | Only activated heads |
| Response time | Fast (detection) | Slower (bulb fusion) |
1.3 Special Hazard Systems — Classification
Special hazard systems include all extinguishing systems other than conventional water-based ones. They are divided into:
Foam systems (NFPA 11): for flammable liquids, hydrocarbons.
Clean agent systems (NFPA 2001): inert gases (IG-541, IG-55), fluoroketones (FK-5-1-12), HFC-227ea. Used for computer rooms, archives, electronic equipment.
CO₂ systems (NFPA 12): for electrical hazards, engines, tanks. CO₂ is toxic — asphyxiation hazard.
Water mist systems (NFPA 750): fine droplets, cooling and oxygen displacement.
Dry chemical systems (NFPA 17): for combustible metals (magnesium, sodium) — special powder.
Section 2: Components and Installation of Deluge Systems
2.1 Main Components
A typical deluge system includes:
20.Deluge valve: clapper held closed by water pressure in the detection piping. When pressure drops (detection activated), the clapper opens.
21.Detection piping: network of pipes under air or water pressure containing the detectors. A loss of pressure (detector activation) triggers the valve opening.
22.Open heads: sprinklers without a thermal-sensitive element.
23.Alarm system: hydraulic gong or electric alarm activated by water flow.
24.Test valve: to verify operation without discharging water.
25.Filter and strainer: protects the valve from impurities.
26.Main isolation valve: for maintenance.
2.2 Piping Installation
Deluge system piping must be installed according to the requirements of NFPA 13 (Standard for the Installation of Sprinkler Systems) and NFPA 15 (Standard for Water Spray Fixed Systems). Key points:
Drainage slope: piping must have a minimum slope of 0.5% (5 mm per meter) toward the drains to allow complete water evacuation after testing.
Supports: maximum spacing of 3.7 m for 25 mm to 32 mm pipes, 4.6 m for 40 mm to 50 mm, and 5.5 m for larger diameters (per NFPA 13 Table 17.4.2.1). Supports must be galvanized steel or compatible material.
Fittings: threaded fittings must be sealed with an approved sealant (PTFE, pipe dope). Welded fittings are prohibited on galvanized steel pipes (welding destroys the galvanization).
Identification: each valve must be identified with a label indicating the zone served. Pipes must be painted red (or have a red band) with the text "DELUGE" in white letters.
2.3 Deluge Valve Installation
The deluge valve must be installed:
Vertically (depending on the model) or in the position specified by the manufacturer. Incorrect installation prevents the clapper from closing properly.
Accessible for maintenance and repair. A minimum clearance of 600 mm must be provided in front of the valve.
Protected against freezing: the valve and supply piping must be in a heated or insulated room.
With an upstream isolation valve (main valve) and a pressure gauge upstream and downstream to verify pressures.
2.4 Open Heads — Types and Installation
Open heads are classified by their orientation:
Pendant heads: installed vertically, deflector facing down.
Upright heads: installed vertically, deflector facing up.
Sidewall heads: mounted on walls.
For deluge systems, upright heads are the most common because they are less sensitive to obstructions and provide better distribution over horizontal surfaces.
Installation rules (NFPA 13, Chapter 8):
Maximum spacing between heads: 3.7 m for ordinary hazards, 3.1 m for extra hazards.
Maximum distance from a wall: half the spacing between heads.
The vertical distance between the deflector and the ceiling must be 100 mm to 300 mm (unless otherwise specified by the manufacturer).
Heads must be installed straight (neither tilted nor twisted) to ensure uniform distribution.
Section 3: Hydraulic Calculations for Deluge Systems
3.1 Discharge Density and Area of Application
Discharge density (in mm/min) is the water flow rate per unit area. It is determined by the hazard classification (NFPA 13, Table 19.2.3.1.1):
| Hazard Class | Density (mm/min) | Area of Application (m²) |
|---|
| Ordinary Hazard 1 | 6.1 | 279 |
| Ordinary Hazard 2 | 8.1 | 279 |
| Extra Hazard 1 | 12.2 | 232 |
| Extra Hazard 2 | 16.3 | 232 |
| Extra Hazard 3 | 20.4 | 232 |
For a deluge system, the area of application is the total area covered by the system (all open heads). The total required flow rate is calculated as follows:
Q = D × A
Where:
Q = total flow rate (L/min)
D = density (mm/min)
A = total area (m²)
Example: A deluge system protects an area of 150 m² with a density of 12.2 mm/min.
Q = 12.2 × 150 = 1830 L/min
3.2 Required Pressure at the Most Remote Head
The minimum pressure at the most remote head is calculated using the NFPA 13 formula (Equation 23.4.2.2):
P = (Q / K)²
Where:
P = pressure (bar)
Q = head flow rate (L/min)
K = head discharge factor (L/min/bar^0.5)
Example: A head with K = 80 must deliver a flow rate of 114 L/min.
P = (114 / 80)² = (1.425)² = 2.03 bar
3.3 Pressure Loss in Piping
Pressure loss is calculated using the Hazen-Williams formula (NFPA 13, Equation 23.4.3.1):
ΔP = 6.05 × 10⁵ × (Q^1.85) / (C^1.85 × d^4.87) × L
Where:
ΔP = pressure loss (bar)
Q = flow rate (L/min)
C = roughness coefficient (120 for black steel, 140 for copper, 150 for CPVC)
d = inside diameter (mm)
L = equivalent length (m) — includes fittings (elbows, tees, valves)
Typical equivalent lengths (NFPA 13, Table 23.4.3.2.1):
| Fitting | 25 mm | 50 mm | 80 mm | 100 mm |
|---|
| 90° elbow | 1.5 m | 3.1 m | 4.9 m | 6.7 m |
| 45° elbow | 0.8 m | 1.5 m | 2.4 m | 3.4 m |
| Tee (straight through) | 0.9 m | 1.8 m | 3.0 m | 4.3 m |
| Gate valve | 1.2 m | 2.4 m | 4.0 m | 5.5 m |
3.4 Required Supply Pressure
The total pressure required at the source is the sum of:
84.Pressure at the most remote head (P₁)
85.Pressure loss in the piping (ΔP)
86.Pressure loss through the deluge valve (ΔP_valve — provided by the manufacturer, typically 0.3 to 0.7 bar)
87.Elevation difference (0.1 bar per meter of height)
P_source = P₁ + ΔP + ΔP_valve + (0.1 × H)
Where H = height in meters between the valve and the highest head.
Section 4: Foam Systems
4.1 Principles and Types of Foam
Foam is a mixture of water, foam concentrate, and air. It works by:
Smothering: the foam layer prevents oxygen from reaching the fuel.
Cooling: the water contained in the foam absorbs heat.
Vapor suppression: prevents evaporation of flammable liquids.
The main types of foam concentrates (NFPA 11):
| Type | Concentration | Application |
|---|
| AFFF (aqueous film forming foam) | 1%, 3%, 6% | Hydrocarbons, spill fires |
| FFFP (film forming fluoroprotein) | 3%, 6% | Hydrocarbons, alcohols |
| AR-AFFF (alcohol resistant) | 3%, 6% | Polar solvents (alcohols, ketones) |
| Protein | 3%, 6% | Hydrocarbons only |
4.2 Installation of Foam Systems
Foam systems can be:
Foam deluge systems: foam is discharged through open heads.
Foam maker systems: for storage tanks.
Injection systems: foam is injected into a conventional water network.
Key components:
Concentrate tank: must be sized to supply the required foam volume for the application duration (typically 15 to 30 minutes).
Proportioner: device that mixes the concentrate with water at the correct ratio (1%, 3%, 6%). Types: venturi, metering pump, pressurized tank.
Foam generator: for high-expansion systems (ratio 500:1 to 1000:1).
Concentrate volume calculation:
V_concentrate = Q_water × C × T
Where:
V_concentrate = concentrate volume (L)
Q_water = water flow rate (L/min)
C = concentration (0.03 for 3%)
T = application duration (min)
Example: Water flow rate of 2000 L/min, 3% concentration, 20 min duration.
V_concentrate = 2000 × 0.03 × 20 = 1200 L
4.3 Specific Installation Requirements
Foam piping must be stainless steel or carbon steel with an internal lining (foam concentrate is corrosive).
Valves and fittings must be compatible with the concentrate (no brass or copper for certain agents).
The concentrate tank must be installed in a heated room (concentrate freezes at approximately 0 °C) and ventilated.
A sampling point must be installed to verify the actual mixture concentration.
Foam tests must be conducted with a test concentrate (less expensive) rather than the actual concentrate, except for acceptance tests.
Section 5: Clean Agent Systems (NFPA 2001)
5.1 Clean Agents — Characteristics
Clean agents are gases that leave no residue after evaporation. They are used to protect electronic equipment, computer rooms, archives, and museums.
| Agent | Formula | Typical Design Concentration | Discharge Time |
|---|
| HFC-227ea (FM-200) | CF₃CHFCF₃ | 7 to 9% | ≤ 10 s |
| FK-5-1-12 (Novec 1230) | CF₃CF₂C(O)CF(CF₃)₂ | 4.2 to 5.5% | ≤ 10 s |
| IG-541 (Inergen) | 52% N₂, 40% Ar, 8% CO₂ | 34 to 52% | ≤ 60 s |
| IG-55 (Argonite) | 50% N₂, 50% Ar | 34 to 52% | ≤ 60 s |
5.2 Agent Quantity Calculation
The quantity of agent is calculated using the volumetric concentration method (NFPA 2001, Chapter 5):
W = (V / S) × (C / (100 - C)) × K
Where:
W = agent mass (kg)
V = protected enclosure volume (m³)
S = specific volume of the agent at ambient temperature (m³/kg) — for HFC-227ea, S = 0.1269 + 0.0005 × T (°C)
C = design concentration (%)
K = safety factor (generally 1.0 for tight enclosures, 1.2 for enclosures with openings)
Example: Enclosure of 500 m³, HFC-227ea, 8% concentration, 20 °C temperature, K = 1.0.
S = 0.1269 + 0.0005 × 20 = 0.1369 m³/kg
W = (500 / 0.1369) × (8 / (100 - 8)) × 1.0 = 3652 × 0.087 = 317.7 kg
5.3 Cylinder and Piping Installation
Agent cylinders must be installed vertically and securely fastened (seismic resistance).
The cylinder room temperature must be maintained between 15 °C and 35 °C (agent pressure varies with temperature).
Piping must be black steel (no galvanization — chemical reaction with the agent) or stainless steel.
Discharge nozzles must be installed according to the manufacturer's calculations (orientation, height, distance from walls).
A leak test (pressure test) must be performed at 1.5 times the service pressure for 10 minutes.
Safety locks must be installed to prevent accidental discharge during maintenance.
5.4 Safety Requirements
An audible and visual warning (siren + strobe) must be installed outside the protected enclosure.
An evacuation delay of 30 to 60 seconds must be programmed before discharge.
Openings (doors, ventilation grilles) must close automatically before discharge (dampers).
A control panel must display the system status (normal, alarm, discharge).
Section 6: CO₂ Systems (NFPA 12)
6.1 Principles and Hazards
CO₂ (carbon dioxide) is an inert gas that extinguishes fire by reducing the oxygen concentration to below 15%. It is effective for electrical hazards, engines, and storage tanks.
Major hazard: CO₂ is toxic at concentrations above 4%. A discharge in an occupied enclosure can cause asphyxiation. CO₂ systems are therefore prohibited in normally occupied enclosures (except for local application systems with directional nozzles).
6.2 Types of CO₂ Systems
Total flooding system: discharges into the entire enclosure. Minimum concentration of 34% for surface fires, 50% for deep-seated fires (NFPA 12, Table 5.4.2.1).
Local application system: discharges directly onto the protected equipment (engine, tank). Used when the enclosure is too large for a total flooding system.
Hand-held systems: portable extinguishers.
6.3 CO₂ Quantity Calculation
For a total flooding system, the quantity is calculated using the volumetric method (NFPA 12, Chapter 5):
W = V × C × K
Where:
W = CO₂ mass (kg)
V = enclosure volume (m³)
C = concentration factor (0.34 for 34%)
K = compensation factor for openings (1.0 to 1.5)
Example: Enclosure of 200 m³, 34% concentration, K = 1.1.
W = 200 × 0.34 × 1.1 = 74.8 kg
6.4 CO₂ Cylinder Installation
Cylinders are installed vertically, secured with clamps.
The temperature of the cylinder room must be maintained between 0 °C and 50 °C.
Cylinders are connected to a manifold that distributes the CO₂ to the nozzles.
A weighing device or pressure gauge must be installed to verify the charge.
Piping must be black steel or stainless steel, with welded or threaded fittings (no brazing).
Nozzles must be installed at the height and orientation specified by the calculations (typically 2 to 3 m from the floor, directed toward the hazard).
Section 7: Water Mist Systems (NFPA 750)
7.1 Principles
Water mist uses special nozzles that produce very fine droplets (less than 1000 microns). The extinguishing mechanism is twofold:
Cooling: the surface area of the droplets is very large, which accelerates heat absorption.
Oxygen displacement: the water vapor produced dilutes the oxygen around the fire.
7.2 Types of Systems
High-pressure systems (70 to 120 bar): use high-pressure pumps or nitrogen cylinders. Droplets of 10 to 50 microns.
Medium-pressure systems (12 to 34 bar): droplets of 50 to 200 microns.
Low-pressure systems (less than 12 bar): droplets of 200 to 1000 microns.
7.3 Installation
Piping must be stainless steel (for high-pressure systems) or copper (for low-pressure systems).
Nozzles must be installed according to the manufacturer's calculations (typical spacing of 2 to 3 m).
A filter of 100 microns minimum must be installed upstream of each nozzle (the orifices are very small).
Pumps must be installed with a backup power supply (generator or nitrogen cylinders).
Discharge tests must be conducted with clean water (no additives).
Section 8: Commissioning and Testing
8.1 Hydrostatic Tests
Before commissioning, all systems must undergo a hydrostatic test:
Test pressure: 1.5 times the maximum service pressure, or 14 bar minimum (NFPA 13, Chapter 24).
Duration: 2 hours minimum.
Acceptance criteria: no leaks, no permanent deformation.
8.2 Deluge System Operational Tests
197.Deluge valve test: open the test valve and verify that the valve opens, the alarm sounds, and water flows from the heads.
198.Detection test: activate a detector (smoke, heat) and verify that the valve opens within 30 seconds of activation.
199.Pump test: start the fire pump and verify pressure and flow rate.
200.Alarm test: verify that the electric alarm and hydraulic gong operate.
8.3 Gas System Tests
202.Leak test: pressurize the piping with nitrogen to 1.5 times the service pressure, maintain for 10 minutes, verify no leaks (pressure drop less than 0.5%).
203.Discharge test: discharge a test cylinder (or the entire system) and verify the agent concentration in the enclosure (with gas analyzers).
204.Delay tests: verify that the evacuation delay is respected (30 to 60 seconds).
Section 9: Applicable Codes and Standards
The following standards are the main references for the Red Seal exam:
| Standard | Title | Application |
|---|
| NFPA 13 | Standard for the Installation of Sprinkler Systems | Sprinkler systems (including deluge) |
| NFPA 15 | Standard for Water Spray Fixed Systems | Fixed water spray deluge systems |
| NFPA 16 | Standard for the Installation of Foam-Water Sprinkler and Foam-Water Spray Systems | Foam-water systems |
| NFPA 11 | Standard for Low-, Medium-, and High-Expansion Foam | Foam systems |
| NFPA 12 | Standard on Carbon Dioxide Extinguishing Systems | CO₂ systems |
| NFPA 2001 | Standard on Clean Agent Fire Extinguishing Systems | Clean agent systems |
| NFPA 750 | Standard on Water Mist Fire Protection Systems | Water mist systems |
| CSA B149.1 | Natural Gas and Propane Installation Code | For gas systems (if applicable) |
| Canadian Electrical Code, Part I | Safety requirements for electrical installations | For detectors and power supply |
Important note: In Canada, NFPA standards are adopted by reference in provincial and territorial codes. The National Building Code of Canada (NBC) requires the installation of sprinkler systems in certain buildings, but the installation details are governed by NFPA 13.
Section 10: Common Pitfalls to Avoid
210.Confusing open and closed heads: in a deluge system, all heads are open. If you see a glass bulb on a deluge system head, it is an installation error.
211.Forgetting the drainage slope: deluge piping must have a minimum slope of 0.5% toward the drains. Perfectly horizontal piping is a defect.
212.Neglecting the equivalent length of fittings: in pressure loss calculations, you must always add the equivalent lengths of elbows, tees, and valves. Many candidates forget this step.
213.Using the wrong C coefficient: for black steel, C = 120; for copper, C = 140; for CPVC, C = 150. Using C = 120 for all materials is a frequent error.
214.Confusing density and flow rate: density is in mm/min (or L/min/m²), flow rate is in L/min. Do not add them directly.
215.Forgetting the elevation pressure: each meter of height adds 0.1 bar of required pressure. For a 30 m building, this represents an additional 3 bar.
216.Installing CO₂ cylinders in a non-ventilated room: CO₂ can leak slowly and create a hazardous atmosphere.
217.Using galvanized piping with clean agents: galvanization reacts with certain agents (HFC, FK-5-1-12) and can clog the nozzles.
218.Forgetting the evacuation delay: for gas systems, a 30 to 60 second delay is mandatory before discharge.
219.Not verifying material compatibility with foam: copper and brass are incompatible with certain foam concentrates.
Summary
A deluge system uses open heads and a deluge valve activated by external detection. It discharges water over the entire protected area simultaneously.
Special hazard systems include foam, clean agents, CO₂, and water mist. Each type has its own standards (NFPA 11, 12, 2001, 750).
Hydraulic calculations follow the Hazen-Williams method: pressure loss = 6.05 × 10⁵ × (Q^1.85) / (C^1.85 × d^4.87) × L.
Discharge density is determined by the hazard class (6.1 to 20.4 mm/min).
Hydrostatic tests must be performed at 1.5 times the service pressure for 2 hours.
Gas systems require volumetric concentration calculations and specific leak tests.
Safety is paramount for CO₂ systems (asphyxiation hazard) and clean agent systems (mandatory evacuation delay).
NFPA standards are the primary references, adopted in Canada through provincial and territorial codes.
Final Exam Tips
Memorize the formulas: Q = D × A, P = (Q/K)², ΔP = 6.05 × 10⁵ × (Q^1.85) / (C^1.85 × d^4.87) × L.
Know the densities by hazard class (NFPA 13 Table 19.2.3.1.1).
Be able to identify the components of a deluge system on a schematic (deluge valve, detectors, open heads, test valve).
Understand the differences between total flooding and local application systems for CO₂.
Review the equivalent lengths of common fittings (90° elbow, tee, valve).
Practice the calculations with numerical examples until you can do them without a calculator (for simple values).
Good luck with your Red Seal exam preparation!
