The reliability of the fire protection pipe system is directly related to the efficiency of fire rescue. Its material selection and installation must comply with strict international standards (such as NFPA, GB 50016). The following is a systematic analysis from three dimensions: pipe type, installation steps, and key points of the specification:
I. Common pipe types and applicable scenarios of fire protection systems
1. Metal pipes
| Type | Advantages | Applicable scenarios | Standards and specifications |
| Galvanized steel pipe | High strength, high temperature resistance (≤200℃) | Indoor fire hydrants, sprinkler pipes | GB/T 3091, NFPA 13 |
| Ductile iron pipe | Strong corrosion resistance, good earthquake resistance | Buried fire pipe network, outdoor fire hydrant system | ISO 2531, EN 545 |
| Stainless steel pipe | Rust-free, high sanitation level | Special places such as hospitals and food factories | ASTM A312, GB/T 12771 |
2. Non-metallic pipes
| Type | Advantages | Restrictions |
| CPVC pipe | Chemical corrosion resistance, easy installation | Only suitable for wet sprinkler systems (temperature ≤ 93°C) |
| HDPE pipe | Good flexibility, impact resistance | Only allowed for underground use (avoid UV aging) |
Key points for selection decision:
Pressure level: Main pipe ≥1.6MPa (GB 50974-2014);
Corrosive environment: 316L stainless steel or internal and external epoxy coated steel pipes are preferred in coastal areas;
Cost considerations: Galvanized steel pipes have the highest cost-effectiveness (accounting for more than 70% of the market share).
II. The whole process of fire protection pipeline installation (taking galvanized steel pipe as an example)
1. Preliminary preparation
Material acceptance:
Check the pipe wall thickness (DN100 pipe ≥4.0mm), the integrity of the galvanized layer (zinc layer ≥80μm);
The valve needs to undergo strength test (1.5 times the working pressure) and sealing test (1.1 times the pressure).
Construction drawings:
Confirm that the pipeline elevation avoids the cable tray (spacing ≥300mm), and the slope ≥0.002 (drainage requirements).
2.Pipeline connection process
| Connection method | Key points for operation | pplicable pipe diameter |
| Groove connection | ① Groove depth error ≤ 0.1mm; ② Tighten the clamp bolt diagonally (torque value refers to the manufacturer’s manual) | DN65~DN300 |
| Threaded connection | ① Number of threads ≥ 11; ② The direction of sealing tape winding is the same as the thread | DN15~DN80 |
| Flange connection | ① Exposed bolt thread ≤ 2 times the pitch; ② The gasket is centered without offset | Valve/equipment interface |
| Welding connection | ① Argon arc welding primer; ② After welding, remove welding slag and apply anti-rust paint | High-pressure main pipe |
3. Key steps of installation
Bracket installation:
Spacing: DN100 horizontal bracket ≤3.5m, vertical bracket ≤5m (GB 50242);
Seismic design: Lateral support (such as C-type channel steel bracket) is installed in earthquake zones.
Pipeline laying:
Fireproof sleeves are required for pipes in suspended ceilings (fill gaps with fireproof mud);
Fire dampers are installed when crossing fire partitions (280℃ fuses and closes).
System pressure test:
Strength test: 1.5 times the working pressure (≥1.4MPa), maintain pressure for 10min without leakage;
Tightness test: 24h pressure drop under working pressure ≤0.02MPa (GB 50261).
4. Anti-corrosion and identification
Galvanized layer damage treatment:
Spray zinc-rich primer (60μm) + fire-retardant topcoat (color: fire red RAL 3000);
Identification requirements:
The arrow on the surface of the pipe indicates the direction of water flow, and the system name sign (such as “XF -Spray”) is set every 20m.
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III. Installation specifications for special scenarios
1. Buried pipeline construction
Anti-corrosion measures:
Three-layer PE anti-corrosion layer (epoxy powder + adhesive + polyethylene);
Cathode protection (sacrificial anode magnesium alloy).
Backfill requirements:
Fine sand cushion ≥100mm, pipe top soil depth ≥0.8m (antifreeze zone ≥1.2m).
2. High-bay warehouse sprinkler system
Pipeline selection:
ESFR (Early Suppression Fast Response) sprinkler, equipped with thick-walled steel pipe (SCH40);
Installation accuracy:
Nozzle positioning error ≤50mm, obstacle distance ≥300mm (NFPA 13).
IV. Common installation problems and solutions
| Problem | Cause | Solution |
| Abnormal noise from pipe vibration | Bracket spacing is too large/no shock-absorbing pads are installed | Add brackets + rubber shock-absorbing pads (thickness ≥ 10mm) |
| Flange interface leakage | Uneven gasket pressure | ighten the bolts in a cross sequence 3 times |
| Nozzle blockage | Incomplete pipe flushing | Flush in sections until the outlet water turbidity is ≤ 5NTU |
V. Acceptance Standards and Documents
Required Inspection Items:
Pipeline pressure test report, anti-corrosion inspection record (spark leak detection ≥ 3000V);
System acceptance certificate issued by the fire department.
Completion Data:
Pipeline welding flaw detection report (RT/UT inspection), valve pressure test record, hidden engineering images.
Conclusion
Fire protection pipe installation is a systematic project, which requires the coordination of material performance, process accuracy and compliance with specifications:
Material selection: galvanized steel pipes (indoor) and ductile iron pipes (buried) are preferred;
Process core: groove connection ensures accurate torque, and the pressure test process strictly adheres to the pressure threshold;
Compliance bottom line: All operations must comply with GB 50974-2014 “Technical Specifications for Fire Protection Water Supply and Fire Hydrant Systems” and NFPA standards.
Only through standardized construction and strict acceptance can a reliable fire protection lifeline be built.