Belden Essential Cable Facts: Smoke and Halogen

Flame retardancy is important but so is the choice of a cable that emits smoke in very low levels and more importantly – without harmful corrosive and toxic gases. Despite stricter legislation lives and equipment are still put at risk due to the use of halogenated cables or cables that scarcely meet recommended industry standards.

Which cable components are critical?

When it comes to the emission of smoke and halogen, key components are:

  • Insulation is a dielectric that separates the cable conductors both physically and electrically. Its primary function is to protect the conductor and support the transfer of electric energy from point to point.
  • The cable jacket is an outer covering. Its primary role is to protect the internal cable components from the external environment.

What's the threat of smoke and halogen emission?

PVC has long been used as an appropriate cable insulation and jacketing material with a high degree of flame retardancy. However, in the event of a fire this will generate dense black smoke, with toxic and corrosive gases that pose a great threat.

 A cable can be low smoke and fume and yet still release toxic and corrosive gases when ignited. 

What risks does this pose to a building or system?

  • System failure: equipment will be damaged by the corrosive gases.
  • Health risks: the effect of inhalation of toxic gases can be fatal.
  • Safety hazards: The dense black smoke impairs visibility and means of escape.

What is a Low Smoke Non Halogen Cable?

To create a true Low Smoke Non Halogen cable, manufacturers must ensure that their cable designs incorporate non halogenated materials for both the cable insulation and the cable jacket. For a cable to be classified as Low Smoke Non Halogen, it must be fully compliant with IEC 61034-2 and IEC 60754 standards.

What is a Low Smoke Non Halogen Cable? Image


Please note the difference between LSF (Low Smoke and Fume) and LSNH (Low Smoke No Halogen). A cable can be low smoke and fume and yet still release toxic and corrosive gases when ignited. Despite its low smoke generation, this classification of cable still typically contains PVC based compounds and will release toxic and corrosive gases when ignited.

Be Certain

All Belden low smoke non halogen materials are fully compliant with all relevant IEC standards, have excellent flame retardancy and deliver an outstanding performance so you can be assured that your application is fully compliant for maximum safety and assurance. Be certain. Check the cable specification to ensure the insulation and jacketing materials are flame retardant, low smoke and non halogen.