LSZH: Low Smoke Zero Halogen; PVC: Polyvinyl Chloride, containing chlorine and halogens. The first principle for selection: for enclosed spaces / areas with a large number of people / fire evacuation routes, choose LSZH; for ordinary open environments and those with limited budgets, choose PVC.
I. Key Performance Comparison
|
Item |
PVC cable |
LSZH low-smoke and halogen-free cable |
|
Halogen |
Chlorine (halogen) |
Halogen-free (without chlorine, fluorine, etc.) |
|
Product of combustion |
A large amount of black thick smoke, releasing HCl (hydrogen chloride), a corrosive and toxic gas. When it comes into contact with water, it forms hydrochloric acid, which can corrode equipment and irritate the respiratory tract. |
The smoke output is very small, with light and pale smoke, almost no halogenated acid toxic gases. The combustion products are mainly water vapor, and have extremely low corrosiveness to equipment. |
|
Temperature resistance |
Ordinary PVC can withstand 70℃ for a long time; Heat-resistant PVC can reach up to 90℃. |
Commonly at 90℃ for a long time, with better thermal stability |
|
Mechanical feel |
The outer skin is soft, bends well, is durable and scratch-resistant, and is easy to bend during installation. |
Harder in texture, the surface is prone to scratching. It becomes more brittle at low temperatures and requires a larger bending radius. |
|
Cost |
Cheap, commonly used in engineering, of economical type |
The price is significantly higher than PVC (20% - 60% higher, depending on the specification) |
II. Applicable Scenarios (Selection Focus)
✅ Must / Preferentially select LSZH (WDZ, WDZN series cables)
For places where fire safety is mandatory or recommended, ensuring personnel evacuation and protecting precision equipment:
- Metro, tunnels, underground pipe galleries, underground garage cable shafts
- Hospitals, schools, shopping malls, airports, stations, etc. - densely populated public buildings
- High-rise buildings, evacuation corridors, smoke exhaust and ventilation machine rooms
- Data centers, computer rooms, control rooms (fire-induced toxic gases can corrode servers and weak electrical equipment)
Domestic fire safety regulations: Class I high-rise buildings, densely populated places, underground enclosed spaces, usually require low-smoke and halogen-free cables
✅ Select PVC (ZR-PVC flame-retardant PVC, BV/RVV, etc.)
For ordinary places without mandatory low-smoke and halogen-free requirements:
- Ordinary single-story factories, outdoor overhead, direct burial, ordinary home decoration (non-high-rise public buildings)
- Open spaces, well-ventilated areas, where personnel do not stay for a long time
- Budget constraints, only requiring basic flame retardancy, not requiring low-smoke and halogen-free
Note: PVC can also be made into flame-retardant PVC (ZR-PVC), flame retardancy does not mean low-smoke and halogen-free; when on fire, it still emits a large amount of black smoke and releases halogenic toxic gases.
III. Common Selection Misunderstandings
- ❌ "Flame-retardant PVC is equivalent to low-smoke and halogen-free" Flame retardancy only prevents the spread of flames; no matter how flame-retardant PVC is, it still emits a large amount of black smoke and releases halogenic toxic gases.
- ❌ LSZH = Non-combustible LSZH is a type of flame-retardant, low-smoke, and non-toxic, not non-combustible. Even with continuous exposure to a flame, it will still burn.
- ❌ LSZH has better electrical performance. With the same insulation structure, the electrical load capacity is basically the same; the difference lies in the fire safety characteristics, not the conductivity.
IV. Construction Tips
- LSZH: The bending radius should be enlarged. During handling and laying, pay attention to protecting the outer sheath, as it is prone to being scratched; in low-temperature environments, pay attention to preventing cracking.
- PVC: Good flexibility, convenient for laying, wear-resistant, good outdoor direct burial protection performance.
