The European market is demanding that cables used in LANs, WANs, etc. meet LSZH specification. The IEC -1 governs the Flame Retardant Grade specifications in reference to LSZH cables.
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Reduction of dangerous/poisonous gasesEssentially, the compound used in manufacturing cables meeting the above specification reduces the amount of dangerous/poisonous gases in case of fire. The main difference in specifications between IEC -1 versus UL® , UL and UL 910 is that the cable under the IEC spec can continue to burn while still emitting very low gases. The UL specs demand that the flame be extinguished, but it can still emit dangerous/poisonous gases.
IEC specificationToday virtually all medium and large installations in Europe must meet the IEC specification. Many public authorities are already demanding that new installations must meet IEC -3 which is a more demanding flammability specification for LSZH. IEC for smoke emission is part of all Black Box LSZH bulk cables.
What's the difference between PVC and LSZH cables
Physically, PVC and LSZH are very different. PVC patchcords are very soft; LSZH patchcords are more rigid because they contain the flame retardant compound, and they are aesthetically more pleasing
A PVC cable (made of polyvinyl chloride) has a jacket that gives off heavy black smoke, hydrochloric acid, and other toxic gases when it burns. Low Smoke Zero Halogen (LSZH) cable has a flame-resistant jacket that doesn't emit toxic fumes even if it burns.
LSZH more expensive and less flexibleLSZH cables usually cost more than the equivalent PVC cable, and certain types are less flexible. LSZH cable does have some restrictions. According to CENELEC standards EN, , , screened cables must be halogen free. However, no similar regulation yet applies to unscreened cables.
Where do you run the cable?
Whether you choose a riser (PVC), plenum or LSZH jacket depends on where you're going to run the cable.
PVC cable is commonly used for horizontal runs from the wiring centre. You can use it for vertical runs between the floors - but only if the building features a contained ventilation system running through the duct work.
LSZH cable is used between floors in a building. It has a special flame-retardant coating.
A plenum is a space within the building created by building components, designed for the movement of environmental air.
Building showing plenum cable (red) and riser cable (blue).
Learn more: Solid vs Stranded Patch cables
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You are planning to purchase some network cables for your new Ethernet setup or home theater to run through, and you already know exactly the category of network cables and the lengths you need. So, you head to the first page of a site or go offline to buy. However, you encounter a new problem: how to choose the right type of cable jacket? PVC, PE, or LSZH? If you are not clear about the differences and pros and cons of these cable jackets, you might end up buying cables that are unsuitable for your needs or waste valuable time deciding which type to choose.
FS can provide customers with a whole range of cables for all purposes with different cable jackets, and these network cable products are all available for immediate delivery. The differences in cable jacket types determine their suitability for different scenarios. To choose the most suitable cables for your application, let's first understand these three types of cable jackets that FS provides.
PVC stands for Polyvinyl Chloride, a widely used plastic material. PVC is chosen for its durability, cost-effectiveness, and ease of processing. It has excellent electrical insulating properties and provides adequate protection against physical damage and environmental factors.
The features of PVC cable jackets that make them widely used typically include:
Superior Mechanical Performance: PVC offers high tensile strength, bending strength, and impact resistance, as well as good abrasion and weather resistance.
Excellent Chemical Stability: PVC cable jacket resists most organic solvents, acids, and bases. It remains stable in environments with pH values ranging from 0 to 14. This characteristic enables PVC cables to perform well in chemically harsh environments, such as sewage treatment plants and chemical laboratories, significantly broadening their applications.
Low Cost: The mature production process and abundant raw material supply for PVC result in relatively low costs. This makes PVC-jacketed cables competitively priced, meeting the demands of the mass market.
While PVC is low-cost and flexible, it has potential drawbacks. During a fire, this material can release dense smoke and hazardous gases, such as hydrogen chloride.
This issue can be particularly severe if toxic smoke and gases are released in areas that can quickly spread to other parts of a building. Thus, the National Electrical Code (NEC) categorizes PVC cable jackets into three groups according to their fire rating levels: CM, CMR, and CMP. These levels indicate where the cables can be installed to ensure contractors and homeowners use the appropriate outer jacket type for the installation area.
The network cables with PVC outer jackets provided by FS have all passed the UL standards and comply with the fire ratings specified by the NEC. Below is a detailed introduction to these three different fire ratings. You can choose the correct fire rating based on the actual application scenario of your network cables:
Category Fire Rating Description Applications PVC CM Communications Multipurpose Cables marked with CM are mainly used for Ethernet and communication applications. They have passed the "vertical tray flame test," meaning they typically do not propagate flames beyond eight feet. Ideal for home use; they can be installed in walls or ceilings without additional fire protection measures. PVC CMR Communications Multipurpose Riser Cables marked with CMR are for buildings with multiple stories. They prevent fires from spreading between floors and are more resistant to fire than the CM cable. Suitable for multi-story buildings where cables must run vertically between floors; they cannot be used in air ducts. PVC CMP Communications Multipurpose Plenum Cables marked with CMR are designed for "plenum" areas in buildings; They restrict the spread of fire, do not emit toxic fumes when burning and will not combust. Ideal for large commercial buildings, hospitals, and schools; they can also be used where CM and CMR cables are applicable.If you want to learn more, please visit our website lszh compound.
PE stands for Polyethylene, a durable and waterproof plastic material commonly used for outdoor cable jackets. PE cable jackets can withstand harsh weather conditions and UV radiation.
PE has excellent moisture and weather resistance, good electrical properties over a wide temperature range, and is abrasion-resistant. Thus, PE is the standard jacket material for outdoor network cables. FS's outdoor bulk Ethernet cables are made of this material, which enables them to withstand harsh outdoor environments effectively. Moreover, they can be directly buried underground without the need for conduit.
However, one drawback of PE cable jackets is that they do not self-extinguish when burned. When heated to their melting point, they may soften and drip. If the dripping falls onto other combustible objects, it could cause a larger fire. Therefore, using network cables with PE jackets in places sensitive to fire risks is not recommended.
LSZH stands for "Low Smoke Zero Halogen," describing two specific properties of this jacket material. "Low smoke" refers to the reduced amount of smoke produced when the material burns, and "zero halogen" indicates that no halogenated compounds are used in manufacture.
Currently, cables with LSZH jackets are primarily used in Europe. Under the framework of the Construction Products Regulation (CPR) in , Europe has created new cable fire protection classes, requiring a reassessment of building fire safety. If you are planning to purchase cables with LSZH jackets, you may need the following four different fire resistance classes:
Bca: This means that cables with this type of jacket have the highest fire resistance performance and are mainly suitable for bedroom environments, prisons, hotels, accommodation buildings larger than 500 square meters, conference venues, etc.
Cca: This class is commonly used for LSZH cables and is suitable for non-bedroom environments such as factories, offices, classrooms, sports venues, shopping areas, etc.
Dca: If cables are used in bundles for applications related to personal safety, they must meet the Dca fire resistance class.
Eca: Unlike the other three fire resistance classes tested according to the EN standard, Eca is tested according to the EN -1-2 standard and represents the basic requirement for fire resistance. Cables cannot be installed in bundles.
FS currently offers Cat6 and Cat6a network patch cables with LSZH jackets. FS network cables have obtained B2ca, Dca, Eca, and Fca certifications. We can provide a Declaration of Conformity/Performance that states the cables' Euroclass grading, and we add the CE marking to each product.
In fire incidents, the primary danger is not the fire itself but the smoke and gases produced during combustion. When LSZH cables burn, they do not produce toxic gases and emit very little acidic gas, which can reduce harm to personnel and equipment. Furthermore, LSZH cables are less likely to catch fire during an incident and can help prevent the spread of flames and the escalation of the disaster. Therefore, cables with LSZH jackets are typically required in high-safety environments, such as airports, military bases, commercial centers, and other densely populated areas. However, while LSZH offers the best safety, its cost is the highest. The large-scale application of LSZH cables may pose a challenge for individuals or small businesses with limited funds.
Q1: How do I know if I need CMP?
A: CMP jackets are made from low-smoke PVC, or fluorinated ethylene polymer (FEP), so CMP cable burns clean, meaning it does not give off toxic fumes and can self-extinguish. On the other hand, PVC releases thick, poisonous smoke when burned. If your cabling needs to pass through air circulation spaces, such as the gaps between drop ceilings and floors, you need CMP cables to meet fire safety requirements.
Q2: Is LSZH the same as Plenum?
A: Low-smoke zero-halogen is not the same as a plenum. LSZH cables are free from halogenic elements (fluorine, chlorine, bromine, iodine, and astatine), which are very common in PVC material but are toxic when burned.
Q3: What is the difference between outdoor and direct burial outer jackets?
A: Regarding jackets, outdoor and direct burial are similar, but the direct burial cables are filled with gel to prevent water from leaking into the cable.
Q4: Can CMP cables be used in riser places suitable for CMR cables, and vice versa?
A: Due to their high fire resistance rating and low smoke emission characteristics, CMP cables can be used in CMR scenarios. However, they are not recommended for use in CMP scenarios, as they may not meet the strict requirements for smoke and toxic gas emissions in air circulation environments.
Q5: Do cable jacket materials affect cable performance?
A: The cable jacket's material mainly affects the cable's durability and safety, not the network performance itself. However, using unsuitable jacket material in a harsh environment can damage the cable, thus impacting network performance.
FS offers a range of high-quality cable jackets to meet various application needs. Whether you need economical PVC cables, durable PE outdoor cables, or the safest LSZH cables, FS has the right product for you. By choosing FS cables, you get high-quality, reliable, and safety-compliant products that ensure smooth and stable network installation and long-term performance.
Contact us to discuss your requirements of cable compound. Our experienced sales team can help you identify the options that best suit your needs.