Category Archives: Bulk Fiber Cables

Cable Jacket: Should I Choose LSZH or PVC?

When talking about communication cables, we commonly use terms like LSZH and PVC to describe them. These two terms describe the chemical compounds used in production of the cables. As we might be rather familiar with these widely used terms, do you exactly know what they really mean? Or more importantly, which one is better for your project? In this article, we are going to explain these frequently asked questions, by analyzing and comparing LSZH and PVC cables.

Communications-Cable

What LSZH and PVC Stand for?

LSZH—Short for low smoke zero halogen, LSZH is a kind of cable built with a jacket material free from halogenic materials (such as chlorine and fluorine), since the toxic nature of these chemicals when burned. The term “low-smoke, zero-halogen” describes two distinct properties of a cable compound. The term “low- smoke” describes the amount of smoke which a compound emits when burned, while “zero-halogen” describes the amount of halogens used to make the compound. Terms like LSOH, LSHF and LSNH are all proper references for cables possessing low-smoke and zero-halogen properties.

PVC—Polyvinyl chloride (vinyl), a general-purpose plastic jacket material used for cables. Features low in cost and flexible, PVC cable is widely used in applications such as computers, communications and low voltage wiring. In the world of cabling, “PVC” is often used to denote a cable that is not suitable for use in a plenum airspace. PVC can potentially be dangerous in a fire situation, releasing heavy smoke and hydrogen chloride gas, which poses a great threat to human health electronic devices. PVC cables often have a CM, CMG, or CMR rating as defined by the National Electrical Code (NEC).

Differences Between LSZH and PVC Cable

Judging from the physical appearance, the difference between LSZH and PVC cable is very distinct. A PVC cable feels soft and it is smooth, whereas an LSZH cable feels rough since they contain the flame retardant compound and it is stiffer. LSZH cables are more aesthetically appealing than PVC cables. In addition to this, LSZH cable differs from PVC one in at least three aspects:

Cost: LSZH cables are slightly higher in cost than some PVC cables, but they are much safer when it comes to human health and sensitive and expensive electronic equipment. And this should be considered when comparing the cost.

Flexibility: Comparing with PVC compounds, there is a limited range of compound flexibility available for LSZH compounds, so LSZH cable is not recommended for robotic or continuous flex applications.

Heat: When a PVC cable is set on fire, it emits chemical fumes, acids and other toxic gases, which are both corrosive and harmful to human beings and environments. As for LSZH cable that has a flame-resistant jacket, it doesn’t emit these chemical substances even if it burns or exposed to high sources of heat. And it can reduce the amount and density of the smoke.

LSZH-PVC-differences

When Do I Use LSZH or PVC?

It is feasible that LSZH and PVC have equally effective performance in modern buildings. So the decision on which one to choose actually depends on the situation, that is to say, where you are going to run the cable.

PVC cable has been used in built environment for power and control applications for decades. It is commonly used for horizontal runs from the wiring center, or for vertical runs between the floors—but only if the building features a contained ventilation system running through the duct work.

LSZH cable would be more appropriate for places where fire presents a hazard to occupants. We known that the primary danger in the event of a fire is not the fire itself but the smoke and gas produced. Therefore, it is vital that the materials and products that are installed contribute as little smoke and gas as possible when burnt. LSZH cable can be employed in the following situations:

  • Confined spaces with large amounts of cables in close proximity to humans or sensitive electronic equipment, such as submarines and ships.
  • Mass transit, central office facilities and telecommunication applications.

LSZH-cable-application

Conclusion

Even though PVC cable still reigns supreme in wire and cable industry, the use of which has decreased over the past years. On the other hand, LSZH cable technology has advanced significantly, it is well suited to some applications mentioned in this article. Your cabling choice always relays on your specific condition, while to consult with wire and cable experts can also be beneficial.

Knowing Cable Ratings: Plenum and Riser Rated Cable

When doing data and voice cabling in premise environment, there is a common question that every installer may confront: Should I use plenum or riser rated cable? Plenum and riser here indicate flame ratings for cables which are defined by National Electric Code (NEC), with the purpose of preventing the spread of fire and smoke in commercial and residential buildings. Then, what is the difference between plenum and riser rated cable? This article will explain to you by making a comparison between them.

What are Plenum and Riser Cable?

The flame rating of cables differs according to various installation situations. Thus to decide which rating is appropriate for your installation environment is critical. So let’s just begin with the basic definition of the plenum and riser cable.

Plenum Cable: A plenum refers to any enclosed area that facilitates environmental air handling. Such as an air conditioning duct or an air routing drop ceiling. It can be any air space between walls, under floors, or dropped ceilings. Plenum cable is designed with a fire-retardant plastic jacket, that is laid in the plenum spaces of buildings. It is held to the most stringent testing of the cables rated by the NEC, rated for both flammability and smoke generation.

plenum rated cable

Riser Cable: Riser cables do what their name indicates—they rise between non-plenum vertical applications like floors of multi-story buildings. Riser cables may also penetrate either fire rated floors or walls. Described as backbone cables, riser cables serve as the main conduit of a distribution system for data, voice or video. The cables are only subjected to flame tests.

riser rated cable

Difference Between Plenum and Riser Cable in Application

In this part, we will illustrate the difference between plenum rated cable and riser rated cable from the perspective of their common application situations.

Plenum rated cable is usually made with strict standards required by a plenum space. It is installed to prevent contamination of the air. Requirements for plenum cables dictate the rate at which a flame spreads, as well as the maximum amount of smoke a burning cable may produce. This kind of cable can be applied to commercial and multi-family residential buildings. Plenum rated cables may substitute for riser and general purpose rated cables.

plenum and riser cable application

Riser rated cable is typically run between multiple floors of a building through open vertical shafts. Although these pathways do not handle environmental air, they can easily conduct a fire from one floor to the next if the cable is not properly rated. And the vertical spread of flame would pose a big threat to the safety. To minimize the spread of fire, riser rated cable is required for carrying a minimum of a riser rating. Riser cables may be used for different forms of data communications which also include CCTV video access. It is ideal as well for voice communications.

Plenum and Riser Cable in Cabling Design

When deploying cable for indoor applications, to plan and design beforehand is definitely critical yet beneficial. If the cables must be deployed in the plenum, it is important to remember that cables that will be deployed there must reach several standards on flammability, heat resistance, and amount of smoke cable generates when burning. Another essential part of installing cable within a building is riser cable deployment. Since riser cable should go through the whole building, it is rather vulnerable in case of fire. This is why riser cable has even more strict fireproof standards than the plenum one. The picture below illustrates the common design of the plenum and riser rated cable in the building.

plenum and riser cable design

Conclusion

Although cable rating is sometimes overlooked by system designers when selecting cables, it is rather vital to the whole installing environment. We have explained the difference between the plenum and riser cable from the perspective of the common application and cabling design, hope that would be informative enough.