Green Future TST cables new generation of (LSZH) low smoke and halogen free cable technology applications

June 19 14:55 2024

LSZH cable, known as Low Smoke Zero Halogen (LSZH) cable, is a specially designed type of wire and cable.

LSZH cable material is made of a rubber material that is free of halogens (F, Cl, Br, I, At), lead, cadmium, chromium, mercury, and other environmental substances. The insulation material does not release halogen-containing gases in case of combustion and has a low smoke concentration.

LSZH or Low Smoke and Halogen Free material is a cable sheathing material with flame retardant and non-halogenated properties. It produces low levels of smoke and does not contain acidic gases. Since LSZH does not contain halogens such as F, Cl, Br, l, At, all of the above elements are toxic and corrosive when burned. The environment in which LSZH cables are manufactured is also very safe, being made from environmentally friendly rubbers that do not contain environmental substances such as lead, cadmium, chromium and mercury. Therefore, these characteristics of low-smoke halogen-free cables determine the use of low-smoke halogen-free cables in nuclear power plants, subway stations, hospitals, aviation, oil and gas, ships and other important places is very extensive.

lszh cable supplier TST CABLES specializes in the production of high quality low smoke halogen free cables and provides a full range of customized low smoke halogen free cable services for various industries. In addition, we can also customize low smoke halogen free cable assemblies according to customers’ needs. Our company has a strong R&D team responsible for researching, improving and producing low smoke halogen free flame retardant cables.

LSZH Cable Technical Specifications

Cable type: LSZH (Low Smoke Zero Halogen) cable

Measurement: Full range meter, depending on application requirements

Voltage: Range according to application requirements

Temperature: Multiple temperatures depending on the application (Operating temperature range: -100°C to +1400°C, TST cables can be customized according to your actual application scenario)

Standards and certifications: ISO/IEC11801, ANSI/TIA-568-2, Fire Classification Response-Dca, ETL and DELTA certifications, etc.

Application areas for LSZH cables

LSZH cables are commonly used in a variety of applications, including, but not limited to, the following, due to their low smoke and non-toxicity:

Public transportation: subways, buses, airports, tunnels, stations (cars, trucks, buses, airplanes, trains and ships), etc., where there is a high level of pedestrian traffic and a high level of safety requirements, LSZH cables are effective in reducing the risk in the event of a fire.

Construction industry: high-rise buildings, hospitals, schools, hotels, apartments, shopping centers, etc., which need to ensure the safe evacuation of people and reduce secondary injuries in case of fire.

Data Centers: Strict requirements for flame retardant and low smoke characteristics of cables to protect expensive electronic equipment from fire damage.

Petrochemical and chemical industries: The special environments of oil, gas and chemical industries require cables with excellent corrosion resistance and flame retardant properties.

Power transmission: Nuclear power stations, wind power stations, especially in densely populated areas of the power transmission and distribution system, the use of LSZH cable can significantly improve public safety.

LSZH cable characteristics:

Low smoke emission: In case of fire, the amount of smoke released when LSZH cables burn is much lower than that of traditional PVC (polyvinyl chloride) cables, which helps to improve visibility in case of fire and create better conditions for evacuation and fire rescue.

Non-toxic Non-halogen: Halogen elements (e.g. chlorine, bromine) produce toxic gases when burning, causing serious harm to human health and the environment.LSZH cables do not contain halogens, and release almost no harmful gases when burning, which reduces the risk of toxicity to personnel.

Flame retardant: LSZH cables have good flame retardant properties, which can slow down the spread of fire and buy valuable time for fire emergency response. This characteristic makes them ideal for use in environments with stringent fire protection requirements.

Environmentally friendly: Being free of halogens and other hazardous substances, LSZH cables are more environmentally friendly and have less impact on the environment when discarded, which meets the requirements of modern sustainable development and environmental regulations.

Heat and corrosion resistance: The insulation and sheath materials of LSZH cables have good heat and chemical resistance, maintaining good electrical performance and long service life even in harsh environments.

Mechanical properties: Despite the focus on environmental protection and safety, the mechanical strength and flexibility of LSZH cables should not be ignored, and the design takes into account the convenience of installation and durability.

high temperature cables

LSZH cable national standard:

Wire and cable low-smoke halogen-free model reference to the national standard for JB/T10491-2004. low-smoke halogen-free wire refers to the wire insulation material halogen material, in the case of combustion, does not release halogen-containing gases, smoke concentration is low, the reference standard for the JB/T 10491-2004, the model has WDZ-BYJ, WDZ-RYJ and so on.

Low smoke halogen free cable: tensile strength than the general PVC wire, good fire resistance (-30 ℃ ~ 105 ℃), good softness (hardness of 80-90), the voltage range is usually 600/1000V, do not need to add plasticizers will not produce toxic black smoke when burning (will produce a small amount of white smoke), flame retardant materials used in the selection of three kinds of metal oxides containing crystalline water: respectively, at 200 ℃, 300 ℃, 300 ℃ above the loss of halogenated gases, the reference standard JB/T 10491-2004, model WDZ-BYJ, WDZ-RYJ and so on. The flame-retardant material uses three kinds of metal oxides containing crystalline water: at 200℃, 300℃, and above 300℃, the crystalline water is lost.

Difference between LSZH and ordinary PVC cable

There is a big difference between LSZH and normal PVC cables in terms of physical properties. pvc patch cables are softer, while LSZH patch cables are harder and contain flame retardant compounds. lSZH cables are more aesthetically pleasing and safer.

PVC cables are made of polyvinyl chloride, the sheath of which releases heavy black smoke and hydrochloric acid when it burns. Unlike PVC cables, LSZH cables have a fireproof sheath with superior flame retardant properties and burn with little smoke and no corrosive gases.

This reduces the amount of toxic and corrosive gases produced during combustion and protects personnel and equipment.

LSZH Cables – Frequently Asked Questions Guide

Low Smoke Zero Halogen or LSZH is a common term you will encounter when buying or using cables.

It is not just a definition of a material or cable characteristic, but a very important distinction that can ultimately mean the difference between life and death.

LSZH cables are sometimes referred to as ZHLH or simply Halogen Free Cables.

This definition of cable essentially helps to determine the materials used for cable insulation and jacketing.

Any material that is not categorized as LSZH does not qualify.

Countries and industries around the world have strict standards for cable materials and LSZH cables are becoming increasingly popular due to their safety.

What is (LSZH) Low Smoke Zero Halogen Cable?

Low Smoke Zero Halogen cable or LSZH cables are cables that do not contain any halogens in their material composition and do not produce smoke in case of fire.

These cables produce very limited amounts of smoke and toxic gases, especially acid gases.

These cables are suitable for use indoors and in hazardous environments where the threat of fire and harmful gases is high.

They are also essentially flame retardant cables as they are self-extinguishing.

However, they are not completely fireproof, which means they can burn and be damaged if the source of ignition persists.

Low smoke and zero halogen are two separate elements.

Therefore, it is important to understand their respective characteristics.

Low smoke

Low smoke means that the cable sheath produces limited smoke.

This does not mean that it will not burn or produce any smoke at all.

It simply means that the smoke concentration does not reach dangerous levels that would be toxic, reduce visibility and hinder rescue efforts.

This depends entirely on the cable’s sheath material, as the sheath is the first layer that comes into contact with the fire.

In most cases, a flame is not as dangerous as the smoke and gases it produces.

In indoor environments, the majority of casualties in fires are likely to be due to smoke, which can cause breathing difficulties, reduce visibility of exit routes and cause panic.

For example, tests have shown that the visibility of PVC (polyvinyl chloride) can be reduced by up to 50 percent when it burns, and as much as 90 percent within half an hour.

This makes PVC a high smoke material; however, low smoke versions can be produced by adding appropriate additives.

Many international standardization and certification bodies have specific tests and benchmarks to measure the smoke emissions of materials.

Cables must pass these tests to qualify as low smoke cables.

Zero Halogen

Zero halogen simply means that no component, primarily insulation and jacketing, should contain halogens in its composition.

Halogens are made up of five elements, including chlorine (Cl), bromine (Br), iodine (I), fluorine (F), and astatine (At).

The reason for the release of halogens in cables is that when a cable catches fire, it produces toxic gases or liquids, such as highly acidic HCl.

The best example of a non-zero halogen material is PVC because it contains chlorine.

Tests have shown that PVC can produce up to 30% HCl in a fire.

What is the difference between LSZH cables and LSF cables?

Some cables are labeled LSF (low smoke, low fume), which is different from LSZH.

This only covers part of the equation, as LSF cables may still contain halogens in the materials.

For example, low smoke PVC cables are LSF, but not LSZH.

These cables still present the threat of halogen gases when burned.

Typically, LSF cables contain additives to help make them low smoke and low halogen, but not zero halogen.

LSZH cables usually follow more stringent standards than LSF cables.

LSF cables emit halogenated acids well beyond the limits set for LSZH cables.

low-smoke halogen-free flame retardant wire

Low Smoke Halogen Free Cable Materials

LSZH Materials

There are essentially two types of LSZH materials: thermoplastic LSZH and thermoset LSZH.

Thermoplastic LSZH materials can be molded by heating several times, while thermoset LSZH materials can only be molded once.

Therefore, they are not recyclable.

Although PVC is the most common thermoplastic, it is not LSZH because it contains chlorine.

On the other hand, ethylene propylene rubber (EPR) and cross-linked propylene (XLPE) are LSZH.

These two materials are very common in cables along with PVC.

It is important to note that LSZH thermosets may not be as flame retardant as chlorinated thermosets.

This is a trade-off when using LSZH cables, as they may have a slightly lower thermal range than halogenated cables.

That said, cross-linked materials (such as XLPE cables) have a higher thermal range.

Your choice of LSZH material will also depend on other factors, such as the voltage rating of the conductors, environmental conditions and the requirements of the particular application, which the material must meet the specified requirements and tests.

What are the advantages of LSZH cables?

There are clear advantages to using LSZH cables:

Less smoke: LSZH produces very limited smoke and is therefore ideal for indoor areas and poorly ventilated areas. If there is a fire in the home and the cable catches fire, if there is less smoke from the cable, there will be no increase in smoke from other structures and objects in the home.

Self-extinguishing: Most LSZH cables are flame retardant, which means they will not spread fire. While they may not be able to completely resist a fire, they will do their best to avoid being burned if the fire doesn’t last.

No harmful gases: Even if the cable catches fire and burns, it will not produce any harmful gases that could poison people on the premises. This makes these cables much better than halogen-containing cables such as PVC cables.

No delays in rescue: In the event of a fire, smoke can seriously reduce visibility and thus hamper rescue efforts. It can make it difficult for trapped people to find an exit and for fire and rescue teams to access the scene. With less smoke, visibility may be just enough for rescue teams to conduct safe operations and save lives.

What are the international standards for LSZH cables?

There is no universal definition or standard for LSZH cables.

However, most international standardization bodies have tests and standards that cable manufacturers are required to follow in order to certify their cables as LSZH.

Manufacturers must test their cables against the tests described in these standards.

For example, the BS 61032 standard specifies a smoke density test.

The test is carried out in a 3 x 3 x 3 cubic meter chamber.

White light is passed through the chamber from a specific height to measure how smoke impedes the transmission of light.

The test requires a minimum transmission of 60%.

Similarly, another British cable standard, BS EN 60754, requires cables to emit less than 0.5% HCl to meet the zero halogen standard.

What are the standards for low-smoke, halogen-free cables?

The International Electrotechnical Commission (IEC) has its own set of standards and tests to determine if a cable is LSZH.

Below are the three most commonly used standards in the cabling industry:

IEC Standards:

IEC 60332 series: deals with flame propagation test methods for cables to ensure their safety in case of fire.

IEC 61034 series: specifies test methods for smoke density produced by cables during combustion.

IEC 60754 series: relates to tests for acidity (pH) and conductivity of gases produced by the burning of cable materials, ensuring halogen-free characteristics.

Part II of IEC 60754-2 is used to measure conductivity and pH.

The pH value should not be lower than 4.3 and the conductivity value should not exceed 10 uS/mm.

LSZH cables also comply with ISO and European Union (EU) Restriction of Hazardous Substances (RoHS) directives.

ISO Standard:

ISO 14001: Although this is not a standard directly for cable products, it is an environmental management system standard that cable manufacturers can follow to demonstrate the environmental friendliness of their production processes.

ISO 9001: A quality management system standard that ensures high standards of cable production and quality control.

Other standardization bodies around the world may perform similar tests on cables to confirm compliance with the LSZH standard.

A cable is considered to be a true LSZH cable only if it meets the standards set by these specialized bodies.

LSZH cables play a vital role in safeguarding infrastructure and human life. Low smoke and no risk of acidic gases and liquids make these cables a safer choice for indoor wiring. These cables, especially marine cables, have strict standards that must be met in order to be labeled LSZH. Cable manufacturers must comply with standards specific to the markets they serve. As far as cable types and materials are concerned, it depends on what they are used for. tst cables is already available in customized, mass-produced quantities with fast delivery worldwide.

China Lszh Cable Supplier TSTCABLES (, focusing on providing high quality high temperature resistant cable applications and solutions for global enterprises, TST Cables mainly focuses on R&D, manufacturing and sales of PEEK, PI and other series of high-temperature materials; the products are widely used in the fields of oil and gas, shipbuilding, nuclear power, wind power, rail transportation, and military industry.For more information on low-smoke, halogen-free, flame-retardant,Anti-Electromagnetic Interference Cable,high-temperature-resistant cables or to customize cables for your machinery or system, visit   

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