LSZH (Low Smoke Zero Halogen) materials are indeed engineered to emit minimal smoke and no toxic halogenated gases when exposed to high temperatures, making them a preferred choice for enclosed or poorly ventilated environments like optical fiber cable ducts. Below are some examples of LSZH compounds commonly used or suitable for such applications, based on their properties and industry relevance:
1. Polyethylene-based LSZH Compounds (e.g., LSZH PE)
- Often made from modified polyethylene blended with flame-retardant fillers like aluminum trihydrate (ATH) or magnesium hydroxide (Mg(OH)₂), these compounds provide excellent fire resistance, low smoke emission, and flexibility. They are widely used in optical fiber cable jacketing and ducting due to their durability and ease of processing.
2. Thermoplastic Polyolefin (TPO) LSZH Compounds
- These are blends of polypropylene and polyethylene with non-halogenated flame retardants. TPO-based LSZH materials offer a balance of mechanical strength, flexibility, and low smoke properties, making them suitable for cable ducts in confined spaces like data centers or tunnels.
3. Ethylene Vinyl Acetate (EVA) with LSZH Additives
- EVA-based LSZH compounds, enhanced with mineral fillers like ATH, provide good flame retardancy and low toxicity. They are often used in optical fiber sleeving and duct applications where flexibility and resistance to cracking are critical.
4. Polyurethane-based LSZH (LSZH TPU)
- Thermoplastic polyurethane (TPU) formulated with non-halogen flame retardants offers high abrasion resistance and flexibility. While less common, LSZH TPU is used in specialized optical fiber ducts requiring enhanced durability and toughness, such as in industrial or military settings.
5. Non-Halogenated Polyolefin Masterbatches
- These are customizable LSZH compounds, often based on polyolefins like polyethylene or polypropylene, doped with phosphorus-nitrogen flame retardants or hydrated minerals. They are tailored for optical fiber cable ducts to meet specific standards (e.g., IEC 60332 for flammability or IEC 61034 for smoke density), ensuring safety in enclosed installations.
These LSZH compounds are selected based on their ability to meet stringent fire safety standards, such as UL 94 V-0 ratings or compliance with European CPR (Construction Products Regulation) classifications (e.g., B2ca, Cca), while maintaining the physical properties needed for cable duct performance. Their use in optical fiber cable ducts is particularly valuable in environments like subways, aircraft, or high-rise buildings, where evacuation and visibility are critical during a fire.