In the design of halogen-free low-smoke flame-retardant cables, the selection of LSZH cable materials for the inner lining and inner sheath directly affects the cable’s flame-retardant performance, environmental safety, and service life. The inner lining is located between the insulation and the armor, providing cushioning and isolation; the inner sheath is positioned outside the armor, offering overall protection. Both must meet the requirements of being halogen-free, low-smoke, flame-retardant, and environmentally friendly.
I. Material Selection for Inner Lining in Halogen-Free Low-Smoke Flame-Retardant Cables
The inner lining must be non-hygroscopic, possess halogen-free low-smoke flame-retardant characteristics, and be compatible with the insulation system. Commonly used LSZH inner lining materials include halogen-free flame-retardant polyolefin and halogen-free flame-retardant polyethylene (HF-PE), which offer excellent mechanical properties and flame-retardant stability. Extrusion or wrapping processes can be adopted to meet the structural requirements of different cable specifications.
II. Material Selection for Halogen-Free Low-Smoke Inner Sheath
The core requirements for the inner sheath are low smoke, halogen-free composition, and high flame retardancy. Mainstream materials include low-smoke halogen-free flame-retardant polyolefin and EVM rubber (ethylene-vinyl acetate rubber). Low-smoke halogen-free flame-retardant polyolefin releases no toxic halogen acid gases upon combustion, offering good processability and high cost-effectiveness. EVM rubber exhibits outstanding high-temperature resistance, oil resistance, and low-smoke flame-retardant properties, making it widely used in high-end applications such as marine cables, mining cables, and railway cables.
III. Application of EVM Rubber in Low-Smoke Halogen-Free Cable Sheaths
EVM rubber is currently a preferred material for high-end halogen-free low-smoke flame-retardant cable sheaths. It has passed authoritative flame-retardant certifications in marine and mining cable applications. EVM flame-retardant compounds achieve an oxygen index of 38 to 42, produce low smoke emissions, and are non-toxic upon combustion. With a continuous operating temperature range of 90°C to 105°C, as well as excellent resistance to mineral oils and aging, EVM rubber is an ideal material for specialty flame-retardant cables.
IV. Cost and Benefit Analysis of Low-Smoke Halogen-Free Cable Materials
LSZH cable materials are generally more expensive than conventional PVC cables, primarily due to the highly filled environmentally friendly flame-retardant systems such as magnesium hydroxide and aluminum hydroxide. However, in safety-critical applications such as public transportation, data centers, marine vessels, and high-rise buildings, the safety value of low-smoke halogen-free flame-retardant cable materials is irreplaceable. Currently, EVM rubber and high-performance halogen-free polyolefins have achieved cost-effective large-scale applications and have become mainstream choices in the industry.
Conclusion
Selecting the appropriate inner lining and inner sheath materials for halogen-free low-smoke flame-retardant cables requires a comprehensive consideration of flame retardancy, environmental requirements, application scenarios, and cost-effectiveness. ONE WORLD specializes in supplying a full range of LSZH cable materials, including EVM rubber, low-smoke halogen-free flame-retardant polyolefin, and halogen-free flame-retardant cable compounds, providing one-stop cable material solutions and technical support.
For material selection advice, sample testing, or product quotations, please feel free to contact us for professional assistance.
Post time: Mar-31-2026