1. Introduction: Why Australian Tunnels Are Abandoning PVC
引言：为什么澳大利亚隧道正在淘汰 PVC 电缆

Australia’s expanding infrastructure pipeline — including the Sydney Metro, Melbourne Metro Tunnel, WestConnex, and Cross River Rail — has placed fire safety at the centre of cable specification decisions. In enclosed environments such as tunnels, the combustion of conventional PVC-insulated cables releases dense smoke and toxic hydrogen chloride (HCl) gas, severely impeding evacuation and corroding surrounding equipment.^[1][2]

This shift is most clearly illustrated by two product lines from Nexans (Olex brand, Australia’s largest cable manufacturer): Versolex® — the long-established PVC-based flexible power cable, and Envirolex® — its Low Smoke Zero Halogen (LSZH) successor specifically designed for fire-sensitive environments. Understanding the technical, regulatory, and performance differences between these two ranges is essential for engineers specifying cables for tunnel and public infrastructure projects, and for international manufacturers seeking to supply LSZH-equivalent products to the Australian market.^[3][4]

2. Olex Versolex®: The PVC Benchmark
Olex Versolex®：PVC 基准产品

Versolex® is Nexans’ premium range of flexible power cables with PVC-based insulation (designated X-90 or V-90) and PVC sheathing. It has been the workhorse of Australian commercial and industrial electrical installations for decades, rated to 90 °C continuous conductor temperature at 0.6/1 kV. Versolex® cables are manufactured to AS/NZS 5000.1 and AS/NZS 5000.2, and their PVC components meet the Best Practice Guidelines for PVC in the built environment.^[3]

3. Olex Envirolex®: The LSZH Alternative
Olex Envirolex®：LSZH 替代方案

Envirolex® is part of the Nexans Fire Safety Offer, designed as a direct LSZH replacement for Versolex®. It is PVC-free, uses X-HF-110 (cross-linked halogen-free) insulation and HFS-110-TP (halogen-free thermoplastic) sheathing, and is rated to 110 °C continuous — a 20 °C increase over Versolex®. This higher thermal rating delivers a meaningful ampacity advantage in constrained cable routes typical of tunnels.^[4][5][6]

4. Head-to-Head: Versolex® (PVC) vs. Envirolex® (LSZH)
正面对比：Versolex®（PVC）vs. Envirolex®（LSZH）

The following comparison table consolidates every specification point that tunnel engineers and procurement teams need to evaluate when making the PVC-to-LSZH transition decision. The differences go far beyond materials — they encompass thermal performance, fire behaviour, environmental credentials, and long-term total cost of ownership.

5. Australian Regulatory Framework Driving the LSZH Shift
推动 LSZH 转型的澳大利亚法规框架

The transition from PVC to LSZH in Australian tunnels is not voluntary — it is driven by an increasingly prescriptive regulatory environment. AS/NZS 3013 classifies the fire and mechanical performance of wiring system elements; AS/NZS 3000 (the Wiring Rules) mandates compliance with fire safety requirements; and AS/NZS 1670.3 requires low-smoke halogen-free cables in rail transit and underground facilities.^[7][8][9] Infrastructure authorities such as Transport for NSW and the Victorian Department of Transport mandate LSZH cables in all new tunnel projects through their design standards.

6. The Science: PVC vs. LSZH Combustion Behaviour
科学解析：PVC 与 LSZH 燃烧行为对比

When PVC burns, the chlorine atoms in polyvinyl chloride react with hydrogen to produce hydrogen chloride (HCl) gas. In a tunnel fire scenario, this gas creates a highly corrosive acidic atmosphere that damages electrical switchgear, ventilation systems, structural steel, and signalling equipment — often causing secondary damage exceeding the original fire cost. The dense black smoke produced drops visibility to near zero within minutes, critically impeding evacuation. In contrast, LSZH compounds are formulated from halogen-free polyolefin-based materials that release minimal, non-toxic combustion products and maintain light transmittance above 60% during the IEC 61034 smoke density test.^[1][10][11]

7. Electrical Performance Data: Envirolex® Single Core
电气性能数据：Envirolex® 单芯

The following table provides representative DC resistance and dimensional data for the Envirolex® flexible single-core range, illustrating that the LSZH construction maintains full electrical performance equivalence to PVC-insulated alternatives while delivering improved thermal capacity.

8. Australian Tunnel Projects: Where LSZH Is Now Mandatory
澳大利亚隧道项目：LSZH 已成强制要求的场所

The shift is not theoretical — it is already embedded in the specifications of Australia’s largest active infrastructure programmes. Standards such as AS/NZS 3013 for fire and mechanical performance classification and IEC 60332-3 for flame propagation in bunched cables are now standard requirements in tunnel design documentation.^[7][8][2]

9. Feichun LSZH Cable Solutions: Equivalent Performance for Global Projects
飞纯 LSZH 电缆解决方案：为全球项目提供等效性能

Anhui Feichun Special Cable Co., Ltd. (安徽飞纯特种电缆有限公司) manufactures LSZH power cables engineered to meet the same performance envelope as Olex Envirolex®, including compliance with IEC 60332-3, IEC 60754, and IEC 61034 fire testing requirements. Our cables utilise halogen-free cross-linked polyolefin insulation with 110 °C continuous ratings and are available with third-party test certificates from accredited laboratories, supporting specification approval on Australian tunnel and infrastructure projects.

10. Conclusions
结论

The Australian tunnel infrastructure sector has definitively moved from PVC-based cables like Olex Versolex® to LSZH alternatives like Olex Envirolex®. This transition is driven by a clear technical case — reduced smoke generation, elimination of toxic and corrosive halogen gas emissions, superior flame propagation resistance, and a higher 110 °C continuous thermal rating — reinforced by mandatory regulatory requirements under AS/NZS 3013, AS/NZS 1670.3, and the IEC 60332/60754/61034 test framework. For international cable manufacturers and suppliers, the ability to produce LSZH cables that meet this performance and testing matrix is now a prerequisite for participating in Australian infrastructure projects.

References & Sources
参考文献与来源

1. Infrastructure Magazine — “Selecting the right cables for tunnels and overhead transport systems” (2023). infrastructuremagazine.com.au
2. TST Cables — “Requirements and standards for LSZH cables in various countries around the world.” tstcables.com
3. Nexans Australia — Olex Versolex® Flexible Single Core 90 °C Product Page. nexans.com.au (Versolex)
4. Nexans Australia — Olex Envirolex® Flexible Single Core 110 °C Product Page. nexans.com.au (Envirolex Single Core)
5. Nexans Australia — Envirolex® Flexible Multicore Low Fire Hazard Cable. nexans.com.au (Envirolex Multicore)
6. Nexans Australia — Envirolex® 2C+E 4mm² Specifications and Datasheet. nexans.com.au (Envirolex 2C+E)
7. Standards Australia — AS/NZS 3013:2005 Fire and mechanical performance of wiring systems. store.standards.org.au
8. NAN Cable — “Electrical Cable Types in Australia: TPS & XLPE (AS/NZS 5000 Guide).” gdnancable.com
9. IET — “Cables and fire protection FAQs” — LSF vs. LSZH distinction, BS EN 61034, BS EN 60754 compliance. electrical.theiet.org
10. JJ-LAPP — “LSZH Cables Boost Fire Safety in Building Infrastructure.” jj-lapp.com
11. Gudacable — “LSZH Cable Defined: Meaning, Safety Standards & PVC Comparison.” gudacable.com
12. Blackwoods (Wesfarmers) — Nexans Olex Envirolex® 120mm² Product Listing. blackwoods.com.au
13. Greenbuildsupply — “Elevating Safety: Understanding LSZH Conduits” — IEC 60754-1, IEC 61034, NFPA 130. greenbuildsupply.com.au
14. Gudacable — “Complete Guide to IEC Standards for Electrical Cables.” gudacable.com (IEC guide)
15. Nexans Australia — Olex-Flex Flexible LSZH Earth Cable — RHE-3 to AS/NZS 4507. nexans.com.au (LSZH Earth)