What Are Low-Smoke Zero-Halogen Cables?

The core advantages of low smoke halogen-free cables are environmental protection, low toxicity, and low smoke, which can significantly reduce the harm to human health and equipment during combustion, especially suitable for densely populated or enclosed places.

Core Materials: Determining "Low-Smoke Zero-Halogen" Properties from the Source

The key to LSZH cables lies in the materials used for their insulation and sheath layers, primarily halogen-free polyolefins (e.g., modified polyethylene or polypropylene), rather than the polyvinyl chloride (PVC) used in traditional cables.

Halogen-Free: Chlorine, bromine, fluorine, iodine, and astatine are completely excluded, fundamentally preventing the release of corrosive and toxic gases (such as hydrogen chloride) during combustion.

Eco-Friendly Flame Retardants: Inorganic flame retardants like magnesium hydroxide and aluminum hydroxide are added to achieve flame retardancy. These substances only release water vapor during combustion, with no additional toxic emissions.

Heavy Metal-Free: The content of heavy metals (e.g., lead, cadmium, mercury, and hexavalent chromium) is strictly limited, complying with international environmental standards such as the EU’s RoHS. This minimizes soil and water pollution during post-use disposal.

In-Depth Analysis of Core Advantages: Beyond "Low Smoke and Zero Halogens"

Low Toxicity: From "Lethal Harm" to "Risk Reduction"

When traditional PVC cables burn, approximately 500 grams of hydrogen chloride gas is released per kilogram of material. This gas reacts with water to form hydrochloric acid, which not only strongly irritates the human respiratory tract and eyes (causing suffocation or chemical burns) but also rapidly corrodes surrounding electrical equipment and metal pipes, leading to secondary damage after fires.

During combustion, LSZH cables release far fewer harmful gases than national standards (typically requiring halogen acid gas emission ≤ 5mg/g), with no heavy metal ions leached. This minimizes toxic harm to humans and equipment.

Low Smoke Emission: From "Zero Visibility" to "Clear Escape Routes"

Smoke is one of the leading causes of casualties in fires. Traditional cables produce thick black smoke when burned, resulting in visibility often less than 1 meter. This makes it difficult for people to identify escape routes and for rescuers to locate trapped individuals quickly.

The smoke transmittance of burning LSZH cables is ≥ 60% (with some high-quality products reaching over 80%), and smoke density is extremely low. Even in enclosed spaces, good visibility is maintained, buying 3–5 minutes of valuable time for evacuation and firefighting.

Flame Retardancy: Balancing "Non-Spreading" and "Self-Extinguishing"

In accordance with the GB/T 19666 standard, LSZH cables are classified into Flame Retardant Classes A, B, and C, with different classes corresponding to different flame spread rates and self-extinguishing times.

Taking the common Class C flame retardancy as an example: when burned with a specified flame (750℃), the vertical flame spread height of the cable does not exceed 2.5 meters, and it self-extinguishes within 30 seconds after the flame is removed. This effectively prevents fire spread along the cable route.

Weather and Temperature Resistance: Adapting to Diverse Scenarios

Low-Temperature Resistance: Ordinary LSZH cables can be bent and used normally at -40℃, while some specially modified products can withstand temperatures as low as -60℃, making them suitable for cold regions or outdoor low-temperature environments.

High-Temperature Resistance: The long-term operating temperature is typically 70℃–105℃, and some high-temperature-resistant models can reach 125℃, meeting the needs of high-temperature working conditions such as new energy vehicles and industrial equipment.

Aging Resistance: They have strong resistance to ultraviolet radiation and ozone, and are less prone to aging issues like cracking or hardening when used outdoors. Their service life is 3–5 years longer than that of traditional PVC cables.

Key Performance Parameters: Quantifying Product Quality

When selecting or evaluating LSZH cables, focus on the following core parameters, as they directly determine the cables’ safety performance and practical effectiveness:

Typical Application Scenarios: Where LSZH Cables Are Mandatory or Preferred

LSZH cables are not suitable for all scenarios; their application is mainly concentrated in fields with mandatory or high requirements for "safety, environmental protection, and low harm":

Densely Populated Public Buildings: Hospitals (especially operating rooms and ICUs), school classrooms and dormitories, shopping malls, hotels, and subway stations. In the event of a fire, evacuating people from these locations is difficult, and the low-smoke zero-halogen properties of LSZH cables significantly reduce casualty risks.

Enclosed or Special Environments: Subway tunnels, underground parking lots, nuclear power plants, ship engine rooms, and aircraft cabins. These spaces are sealed, making it hard for smoke and toxic gases to dissipate. LSZH cables slow down environmental deterioration.

High-End Manufacturing and New Energy Sectors: New energy vehicles (battery connection wires and high-voltage harnesses), data centers (server power cables), and electronics factories (wiring for precision equipment). These scenarios require not only safety but also strict standards for environmental protection and temperature resistance.

Municipal and Infrastructure Projects: Urban rail transit lines, utility tunnels, and lighting/monitoring wiring for large bridges. These facilities have high maintenance costs and require cables with long service life, environmental friendliness, and safety.