Fiber Resistant LS0H Cables

With the increased demand for safety in public areas and buildings, contractors are now being advised to install materials thar are zero halogen cables to peoples in case of fire. It is now understood that smoke and poisonous fumes can be a greater risk to lives than that of fire alone.

What is Resistance to Fire?
Resistance to fire is the property of a material of assembly to withstand fire or give protection from it and it is measured as the time a product can mantain a level of functionality during a fire.

Fire resistance may be built-in both structurally and by the correct choice and application of building materials. The resistance-to-fire (of a cable) is the term used to describe how long a cable continues to operate in a fire. This may be of primary concern, for instance, in life safety of fire fighting installations.Cable resistance to fiber concerns: the ability of a cable to maintain functionality during fire; the duration of survival in working condition.

To be assured you are buying a cable that will offer security during fire, it must pass 3 tests pertaining to halogen content, low smoke density and flame propagation. The resistance-to-fire performance of cable is indicated in term of survival time which are 15, 30, 60, 90 and 120 minutes of operation in a standardized fire condition at European Level and equipment international (IEC). Local standards and customers specs include their own requirements witch are achieved as well by FiberStore local or tailor-made products.

Fiber-retartant, low smoke halogen free cable (LSZH) and wire has been commercially available fro shipboard applications since the 1970S, offshore marine platforms, rapid transit and similar applications where people are present in confined areas. When worked with other fiber prevention and suppression practices, fire-retardant LSZH cables can help minimize fire-rated deaths and property damage. However, gases produced by all burning materials – whether LSZH or not – are extremely toxic.

Advantages and Disadvantages of LS0H cables

Pro: LSZH wire and cable produces less smoke when burned, which permits people to exit a burning building more quickly and results in less damage.

Con: Because LSZH is more susceptible to jacket cracking caused by pulling lubricants or cable bending, special lubricants has been developed to minimize cable damage during installation.

Pro: Because LSZH releases little or no halogen gas when burned, it reduced the damages to the human respiratory system if inhaled and contributes to less corrosion damage to equipment near the fire.

Cons: LSZH jacket compounds usually have very high filler content to provide the required flame and smoke performance. As a result, most have poorer mechanical, chemical resistance, water absorption and electrical properties than non-LSZH compounds.

Pro: LSZH jackets have a lower coefficient of friction than some non-LSZH jackets, which can make installatin easier.

Cons: The current generation of LSZH cables has not yet established a proven history of long-term performance.

Why do We Run LSZH Cable?

If you have concerns on why do we have to run LSZH cables in some special networking cabling environment, FiberStore editor here is pleased to make it all a little clearer. In this article, we’ll explain a little abut what halogens are, what’s the difference between PVC and LSZH cable, and why do we have to run the LSZH cables.

What halogens are?

A halogen is a nonmetallic element, such as fluorine, chlorine, iodine, or bromine. When exposed to flames, substances made with halogens give off toxic fumes that quickly harm the eyes, nose, lungs, and throat. Did you notice tsat fluorine and chlorine are commonly found in cable insulation and jackets? Even when cables are designed to be flame-resistant, any cable when exposed to high enough temperatures will melt and burn. PVC cables contain chlorine, which emits toxic fumes when burned.

What’s the difference between PVC and LSZH cable?

We know, much of the cable currently in use in the United States and elsewhere in the world contains halogens. The European market is demanding that cables used in LANs, WANs, etc. Meet LSZH specification. The IEC 60332-1 governs the Flame Retardant Grade specifications in reference to LSZH cable.

Essentially the compound used in manufacturing cables meeting the above specifications reduces the amount of dangerous/poisonous gases in case of fire. The main difference in specifications between IEC 60332-1 versus UL 5181, UL 1666 and UL 910 is that the cable under the IEC specifications continue to burn while still emitting very low gases. The UL specs demand that the flame be extinguished, but it can still be emit poisonous/dangerous gases.

A PVC cable is made of polyvinyl chloride. It has a jacked that gives off heavy smoke, hydrochloric acid, and other toxic gases when it burns. Low smoke zero halogen cable has a flame-resistant jacket that doesn’t emit toxic fumes even if it burns. PVC patch cords are soft, while LSZH patch cords are more rigid because they contain the flame retardant compound, and they are aesthetically more pleasing.

Many different fibre optic cable manufacturers are now making low-smoke, zero-halogen (LSZH or LS0H) cables.

These cables are designed to emit no toxic fumes and produce little or no smoke when exposed to flames. Tunnels, enclosed rooms, aircraft, and other minimum-ventilation areas are prime spots for the use of LSZH cables because those areas are more difficult to escape from quickly.

Why do we have to run the LSZH cable?

LSZH cables are popular outside the United States. Some safety advocates are calling for the use of LSZH cables in the United States, specifically for the plenum space. Review your local building codes to determine if you must use LSZH cable. Non-LSZH cables will produce corrosive acids if they are exposed to water (such as from a sprinkler system) when burned; such acids may theoretically further endanger equipment. But many opponents of LSZH cable reason that if an area of the building is on fire, the equipment will be damaged by flames before it is damaged by corrosives from a burning cable.

Why, you might ask, would anyone in his or her right mind argue against the installation of LSZH cables everywhere? First, reducing toxic fumes doesn’t necessarily mean the cable is more

The flame-spread properties are worse than for cables in use today. Numerous studies by Bell Labs showed that cables composed of LSZH will not pass the plenum test, not because of smoke generation but because of flame spread. Most Low Smoke cables designs will only pass the riser test where the allowable flame spread is greater. Second, consider practicality. LSZH is an expensive solution to a problem that doesn’t seem to really exist in the United States.