The outer jacket of a cable is not just a layer of plastic—it is an engineered material that determines how a cable performs under heat, flame, moisture, UV exposure, chemicals, and mechanical stress-1. In the wrong environment, the wrong jacket material can cause failure, pose a fire hazard, or void compliance certification-1.
This guide compares the two most widely used cable jacket materials—PVC (Polyvinyl Chloride) and LSZH (Low Smoke Zero Halogen) —to help engineers make the right selection for industrial instrumentation projects--1.
1. What Are PVC and LSZH?
| Material | Definition | Key Characteristic |
|---|---|---|
| PVC | Polyvinyl Chloride—a versatile thermoplastic compound | Cost-effective, widely available, good mechanical properties- |
| LSZH | Low Smoke Zero Halogen—thermoplastic compounds using halogen-free flame retardants | Emits minimal smoke and no toxic halogen gases when burned-14 |
PVC is the most popular and inexpensive material for cable jackets--8. LSZH cables use halogen-free compounds such as polyolefins that absorb heat and release water during combustion, slowing the fire and reducing damage-11-.
2. Head-to-Head Comparison
| Feature | PVC | LSZH |
|---|---|---|
| Fire Behaviour | Flame resistant but can melt and drip-11 | Self-extinguishing; doesn't melt, drip, or run-11 |
| Smoke Emission | Produces dense black smoke- | Emits very little smoke--11 |
| Toxic Gases | Releases hydrochloric acid (HCl) and chlorine--11 | Non-toxic gases; releases <0.5% hydrogen chloride--11 |
| Corrosion Risk | Acidic gases corrode equipment and infrastructure--11 | Minimal corrosion to nearby electronics--14 |
| Flexibility | Softer, less rigid, easier to handle- | More rigid and firm; less flexible--14 |
| Cost | Lower upfront cost--11 | Higher initial cost, but lower total cost of ownership--11 |
| UV & Moisture Resistance | Good chemical resistance; permeable to humidity--1 | Lower moisture and UV stability unless specially treated-14 |
| Temperature Range | -30°C to 105°C (special grades)- | Varies; thermoplastic grades 70–90°C, cross-linked to 125°C-53 |
| Cold Performance | Can become rigid and brittle in cold weather--8 | Typically better low-temperature performance-8 |
3. Performance in Fire: The Critical Difference
The most significant distinction between PVC and LSZH is their behaviour during a fire:
PVC Fire Performance:
Emits dense, toxic smoke containing hydrochloric acid (HCl)-
Smoke hinders evacuation and causes health issues-11
Hydrochloric acid—when smoke mixes with water—corrodes infrastructure and equipment-11
LSZH Fire Performance:
Meets IEC 60332-1 and can achieve IEC 60332-3A/C with special design-
Complies with IEC 60754-1/2 (halogen-free) and IEC 61034-2 (low smoke)--14
Releases water vapour during combustion, cooling the cable surface and diluting gases-56
The 1988 Illinois Bell fire demonstrated the dangers of PVC: burning cables released chlorine gas, which combined with water to form hydrochloric acid, injuring ten firefighters-11. This incident led to NFPA 76 and highlighted why LSZH cables are critical in enclosed spaces-11.
4. When to Specify PVC
PVC remains a valid choice for many industrial applications where fire safety requirements are less stringent-.
Choose PVC when:
| Criterion | Reason |
|---|---|
| Cost is a primary driver | PVC is the most economical jacket material-8 |
| Installation requires flexibility | PVC is softer and easier to handle- |
| Fire risk is low | Cables not exposed to fire, corrosive chemicals, or abrasion-8 |
| Indoor, non-plenum spaces | Equipment rooms, general industrial areas-56 |
| Instrumentation loops & control panels | PVC shielded instrumentation cable is widely used for systems sensitive to electrical noise- |
Typical PVC applications:
General industrial instrumentation and control cables-
Cable trays, raceways, conduit installations-
Commercial and utility applications-
General-purpose indoor wiring-11
5. When to Specify LSZH
LSZH is the preferred choice wherever fire safety, smoke toxicity, and personnel protection are critical concerns-1.
Choose LSZH when:
| Criterion | Reason |
|---|---|
| Enclosed spaces with people | Hospitals, airports, schools, subways, control rooms-11 |
| Offshore platforms and marine | Reduces smoke and gas emissions in fires- |
| Oil and gas facilities | Refineries, offshore rigs, production facilities- |
| Tunnels and transport infrastructure | Critical for safe evacuation-14 |
| Data centres and control rooms | Protects sensitive electronics from corrosive gases-8 |
| Poor ventilation | Toxic fumes cannot be easily exhausted-14 |
| Regulatory compliance | Meets modern building regulations and fire safety codes-14 |
Typical LSZH applications:
Offshore oil and gas platforms-
Marine and shipboard installations-
Public infrastructure projects-14
Data centres, hospitals, and high-occupancy buildings-8
Any enclosed space where evacuation time is critical-
6. Selection Decision Framework
| Question | Answer | Recommendation |
|---|---|---|
| Is the installation in an enclosed space with people? | Yes | LSZH (safety and evacuation)-11 |
| No | PVC or LSZH depending on other factors | |
| Is the cable in a fire-risk area (refinery, offshore)? | Yes | LSZH (reduced smoke and toxic gases)-1 |
| No | PVC may be acceptable | |
| Is the cable exposed to UV or outdoor conditions? | Yes | PVC (better UV stability) or specially treated LSZH-14 |
| No | Either | |
| Is flexibility critical for the installation? | Yes | PVC (more flexible)- |
| No | LSZH (may be acceptable despite rigidity) | |
| Is cost the primary constraint? | Yes | PVC-8 |
| No | LSZH if safety requirements justify the cost-14 | |
| Is the cable subject to frequent mechanical stress? | Yes | PVC (more abrasion-resistant)-56 or armoured LSZH-14 |
| No | Either |
7. Practical Engineering Considerations
LSZH trade-offs to be aware of:
| Consideration | Impact |
|---|---|
| More rigid | Can pose issues in dynamic or tight-bend installations-14 |
| Less abrasion-resistant | More susceptible to mechanical damage during installation-14-56 |
| Lower moisture resistance | Less ideal for outdoor use unless specially treated or armoured-14 |
| Slower self-extinguishing | LSZH cables generally safer in fire but don't self-extinguish as quickly as halogenated materials-14 |
Installation guidance:
LSZH cables deliver equivalent electrical performance to PVC cables but can be slightly less mechanically rugged—avoid overly tight bends-
For high-temperature environments, choose cross-linked LSZH formulations (105–125°C)-53
For outdoor use, specify UV-resistant LSZH compounds-53
8. Why Choose Anhui Tiankang for Instrumentation Cables?
Anhui Tiankang (Group) Co., Ltd. has been manufacturing industrial cables for nearly five decades. Our instrumentation cable portfolio includes both PVC and LSZH sheathed options to match your specific project requirements.
Cable offerings:
| Sheath Type | Features | Typical Applications |
|---|---|---|
| PVC instrumentation cables | Cost-effective, flexible, good mechanical protection | General industrial, cable trays, control panels- |
| LSZH instrumentation cables | Low smoke, halogen-free, fire-safe | Offshore platforms, control rooms, enclosed spaces- |
| Armoured LSZH cables | Mechanical protection + fire safety | Direct burial, high-risk areas |
| IS/OS shielded cables | Individual and overall shielding options | Critical analogue signals, EMI-sensitive applications |
Core advantages:
Full certifications: CCC, ATEX, IECEx, CCS marine
CNAS-accredited laboratory: Full fire performance testing
Proven track record: Long-term supplier to CNPC, Sinopec, CNOOC, and international EPC projects
Complete package: From instrumentation to cables to Ex cable glands
9. Conclusion
The choice between PVC and LSZH is not about which material is "better"—it is about which is right for the application.
| If your priority is... | Choose... |
|---|---|
| Cost and flexibility | PVC- |
| Fire safety and personnel protection | LSZH-1 |
| Enclosed spaces with people | LSZH-11 |
| Outdoor exposure | PVC or specially treated LSZH-14 |
| Offshore, marine, or tunnels | LSZH- |
| General industrial use | Either—depends on risk assessment- |
The key takeaway: LSZH cables are the safer, more environmentally friendly choice for high-risk and enclosed environments, while PVC cables remain a cost-effective solution for general use-. The right selection depends on fire safety requirements, installation environment, and budget-1.
Contact Us
For instrumentation cable selection advice, technical documentation, or project quotations, please contact:
Yin Shuangjie
International Sales Manager
📧 Email: [email protected]
📱 WhatsApp / Zalo: +86 17856068126
🌐 Website: http://www.tiankang-global.com/
Anhui Tiankang – Your partner for reliable instrumentation cable solutions.
