Low Smoke Halogen Free - What Does It Mean?何为低烟无卤

Low Smoke Halogen Free - What Does It Mean?

By Robert W. Beiiassai, Senior Staff Engineer at UL

何为低烟无卤，来自UL高级工程师的文章。

There is a lot of confusion in the industry regarding claims of low smoke halogen free cables and the materials utilized in these cables.

With an increased focus in the North American market on cables that generate low smoke and halogen content versus flame propagation, Low Smoke Zero Halogen Free cables are gaining interest.

Over the last few years cable manufacturers have been claiming that their Low Smoke Halogen Free products offer increased levels of safety for humans from toxic gases and for sensitive electronic equipment from the corrosivity associated with smoke emissions.

First, we need to consider what a halogen is in terms of the Periodic Table of Elements. The five ⑸ halogen elements considered as shown in column 17 are fluorine (F), chlorine (Cl), bromine (Br), iodine (I) and astatine (At). The three common halogen elements found in wire and cable construction components including insulation, filler, jacket and tape materials are F, Cl & Br.

The table below shows the common sources of halogenated compounds in wire and cable products.

Currently, many wire and cable manufacturers offer self-declared low smoke halogen free cable designs and these declarations take many forms, such as “Low Smoke Zero Halogen (LSZH)” “Halogen Free (HF)”and “Flame Retardant Halogen Free (FRHF). These claims are backed by many different standards and test methodologies. These inconsistencies create confusion among end-users and specifiers regarding the requirements used to consider the cable Low Smoke Halogen Free.

The North American and European markets specify flame and performance requirements differently. The North American market considers flame propagation and or smoke generation a primary concern, while the European market considers halogen content and smoke generation a priority. This shift in priority between the two markets results in many different ways to demonstrate compliance. The predominant industry standards used by wire and cable manufacturers to substantiate Halogen Free (HF) and Low Smoke Halogen Free (LSHF) claims are published by the following: International Electrotechnical Commission (IEC), National Electrical Manufactures Association (NEMA) and the US Military. The specific standards are: IEC 60754-1, IEC 60754-2, IEC 61249-2 Non-halogenated series, IEC 61034-2 & MIL DTL-24643C Part 3.3 (NEMA WC57).