Until recently most cables for LAN installations were PVC sheathed, and halogen free cables were only applied in a few special cases. However, a significant change of attitude and regulation is now developing in the market, for instance in CENELEC standards EN 50167, EN 50168 and EN 50169 by direct specification that screened cables must be halogen free. These new requirements to halogen free cables have impact on the safety and especially the fire rating of the cables, as discussed in the present 3P Newsletter.

Arguments for turning to Halogen Free Cables

PVC is in most respects an ideal sheath material. Superior mechanical characteristics are combined with high reliability. However, two main drawbacks have forced the development of alternative, halogen free sheath materials.
First issue concerns environmental considerations in connection with use of PVC. Key words like "acid rain", "dioxine formation", "pollution with heavy metals", "fertility of man and male animal" and "cancer risk" are popular environmental arguments connected with PVC. Discussion of relevance of the various claimed environmental hazards is interesting, but outside the scope of the present 3P Newsletter.

The second disadvantage forcing substitution of PVC concerns the fire behavior. In a fire situation burning or extensive heat causes:

Development of a heavy black smoke

Development of hydrochloric acid and some poisenous gasses.
Together these two factors affect human safety in case of fire. The smoke causes panic as escape routes cannot be seen. The poisenous gasses cause asphyxiation if people cannot escape the smoke in a short time.
Development of the hydrochloric acid may destroy both electronic equipment, machinery and buildings. The chlorine will contaminate all surfaces exposed to the smoke and may cause severe corrosion in a very short time. There are numerous examples of multi million dollar damages after even a very small PVC fire, in spite of the positive effect of an immidiate cleaning operation.

Benefits and Drawbacks of Halogen Free Sheath Materials

For the above reasons the search for an alternative to PVC has been intensive and proved to be successful. A number of compounds are available today, mainly based on the plastic material "EVA" filled with aluminium or magnesium hydroxyde. Fire retardancy comes from generation of water during fire.
The halogen free materials are normally more expensive than PVC to buy and to process. Consequently the halogen free cables will normally be more expensive than the corresponding PVC sheathed cables. Furthermore, some cables, especially with early compounds, may be more stiff than the corresponding PVC cables.

Fire and Flame Retardancy of Halogen Free Cables

A benefit for the halogen free cables is a better fire performance than possible for PVC cables. Unfortunately a large number of fire and flame tests exist and it is therefore not always clear which fire or flame performance a specific cable offers.
The following ratings can be found for communication cables:

Flame retardancy according to IEC 332-1 (Corresponds to HD 405.1) is verified by burning one cable with a single flame. IEC 332-1 is and will be the fundamental flamability rating for all cable types, including also PVC sheathed cables. All international communication cables must pass this requirement.

Fire Retardancy according to IEC 332-3, Cat. C (corresponding to HD 405.3) is verified by burning a bunch of cables with a large burner. IEC 332-3, Cat. C is the additional flammability rating that presently is mandatory for halogen free screened cables. However, the position with respect to the IEC 332-3, Cat. C requirements is both clear and confused:

Clear requirement: If you install screened cables and need compliance to EN 50173 (and therefore EN 50167, EN 50168 or EN 50169) you must install fire retardant, halogen free cables.

Confusion: No formal fire retardancy requirement exists for unscreened cable. Not because of international disagreement that unscreened cables should also be fire retardant and halogen free, but simply because standardization of unscreened cables is missing due to open EMC discussions.

Furthermore the fire retardancy requirements of screened cables might be reconsidered in the future updates of the standards. The valid argument is being discussed: Why should the halogen free cables be forced to have added costs in order to pass fire retardancy requirements (because of thicker sheath needed), when PVC sheathed cables have never passed this requirement?

Flame and Fire Retardancy according to, or covered by American Ratings like CM, CMX, CMR and UL VW-1
The above American safety ratings cover different flammability tests ranging from a single flame applied to a single cable (but different to the international IEC 332-1 test!) to a very severe testing of bunched cables in a tunnel (Steiner Tunnel Test).
Designations like "CMX" are often found on cables, but for most countries the American safety testing is a tradition from earlier days and should be replaced by the international flammability ratings with associated additional safety and material requirements.

Identification of Halogen Free Cables
There is confusion about the designations for halogen free cables. The most frequent identifications are found below, but abbreviations can be found pairwise in any combination or order:

• LS0H Means "Low Smoke, Zero Halogen"
• LSZH Means "Low Smoke, Zero Halogen"
• HFFR Means "Halogen Free, Fire Retardant"
• FRZH Means "Fire Retardant, Zero Halogen"
• LSFRZH Means "Low Smoke, Fire Retardant, Zero Halogen"

All cable designations are describing the same cable type, except for "FR" since halogen free cables may be either fire or flame retardant.
Additional Safety Requirements for Halogen Free Cables
Halogen free cables are in practice always passing requirements to halogen emission and low smoke generation specified in the relevant safety standards. Furthermore, the mechanical, thermal and ageing characteristics of the halogen free sheath, insulation and total cable are specified for communication cables.
All safety and material requirements are of course verified for 3P qualified halogen free cables. We always identify our qualified halogen cables as LS0H EN & ISO/IEC Communication Cables

Certification Process

1) Send production samples, 25% prepay
2) Testing and evaluation
3) Documentation, final 75% invoice

Samples to be supplied:

Production samples length: Depends on sheath volume pr cable meter, but usually 2-500 metres will be enough. Details will be announced when testing is planned.

Test programme

Safety performance:
Fire safety according to CPD

Testing conditions:
Vertically mounted bunch of cables subjected to a 10 kW flame for 20 min

Cost and Delivery Time

Please contact 3P.