Fire Survival Cable

Fire Survival Cable (or Fire Resistant Cable)

For fire survival mostly 1.5mmX2core cable is use. These cable are designed to sustain with high temperatures. These cables mostly used Glass mica tapes to meet the fire resistance requirements which is wrapped over the conductor.
some common property of these cables are normally operate up to 90°C with Maximum conductor temperature at the termination of short circuit up to 250°C. 

Oxygen Index[or limiting oxygen index(LOI) or Critical oxygen index]

Oxygen index is a parameter the that suggest us about flammability of a substance. As higher the hydrogen to carbon ratio in the polymer, the greater is the tendency to burning. therefore, if oxygen index is higher then material do not burn easily(or less flammable). As air contains approximately 21% oxygen therefore it is stated that if oxygen index of the material is greater than 26% in that case material will be self extinguishing.

Why high oxygen index is good for wire insulation?

Most of our Polymers used in cable industries are derived from ethylene(C₂H₄) such as Ethyelne propylene Rubber(EPR), cross-linked polyethylene, vinyl chloride(C₂H₃Cl),etc.

As Ethylene is highly flammable,But most of our material are derived from this therefore when we are making a substance from it we try to add other substance that increase the intermolecular force, In this way we increase the Ignition temperature(burning temperature). The second way is to decrease the concentration of ethylene. In this earlier we increase the concentration of halogen gases. But as we all know that halogen is very toxic for us therefore as we release that then we chose second option that is increasing the concentration of oxygen.
NOTE:-Oxygen is oxidizer enabling other substances to oxidize(or burn). But Pure oxygen does not "Burn"

In India polycab is one of the company which make different types of Fire Survival Cable.

What are different types of fire survival cables?

1.5 x 2 C Unarmd(Cross Linkable LSZH-LSZH)

1. Type of cable:-Cross Linkable LSZH insulation Outer sheath and Extruded LSZH inner sheath
2. Colour of outer sheath:-RED
3. Core Identification:-Red, Black
4. Fire Performance Circuit intigrity test:- 950°C for 3 Hrs.
5. Material:-Plain annealed Copper Class 2
6. Material of Drain Wire/CPC:- Stranded ATC(1.5 Sq.mm)
7. As it has LSZH material therefore it HCL content in this cable is as low as 0.5% and toxic index less than 5%
8. Printed:-300/500 V

1.5 x 2 C Armd(FRLSH-FRLSH-XLPE)

1. Type of cable:-Armoured, FRLSH(Type ST2 as per IS:5831/84) Outer sheath and inner sheath(Bedding) and XLPE(as per IS 7098) inner insulation
2. Colour of outer sheath:-RED
3. Core Identification:-Red,Black
4. Fire Performance Circuit intigrity test:-750°C for 90 Min.
5. Material:-Plain annealed Copper as per Class 2(as per IS:8130/2013)
6. Printed:-1100 Volt grade XLPE FR-LSH

1.5 x 2 C Armd(LSZH-LSZH-XLPE)

1. Type of cable:-Armoured, Extruded LSZH Outer sheath and inner sheath(Bedding) and XLPE inner insulation
2. Type of cable:-Armoured XLPE Outer sheath and LSZH inner sheath
3. Colour of outer sheath:-RED
4. Core Identification:-Blue, Brown
5. Fire resistant characteristic of electric cables as per IEC 60331:-(950°C for 3 Hrs.)
6. As it has LSZH material therefore it HCL content in this cable is as low as 0.5% and toxic index less than 5%
7. Material:-Plain annealed Copper Class 2 Conductor
8. Printed:-600/1000V
9. Mostly this is Available

1.5 x 2 C [LSZH-LSZH-Ethylene propylene rubber(EPR)]

1. Type of cable:-Armoured,Outer sheath and inner sheath(Bedding) LSZH(Type ST8 as per IEC 60502-1) and inner insulation is EPR(as per IEC 60502-1)
2. Colour of outer sheath:-Black
3. Fire Performance:-IEC 60331 (750°C for 90 minutes)
4. As it has LSZH material therefore it HCL content in this cable is as low as 0.5% and toxic index less than 5%.
5. Material:-Annealed Tinned Class -2 Copper to IEC 60228
6. EPR used in this cable provide it great flexibility

EPR

EPR is a generic term for a wide range of polymers based on co-polymers of ethylene and propylene. like XLPE insulation, EPR also suitable for higher voltage applications. But its dielectric properties are not as good as those of XLPE. But is also have some advantage such as extra flexibility,reduced thermal expansion and low sensitivity to water treeing

What is fire resistant cable used for?

fire resistant cable used for maintain integrity during the fire as it can withstand with 750 C. We commonly see it as fire alarm cable in buildings, malls and in the office.