PVC-Free Conduit Jackets Limit Combustion Products

<b>LSZH Conduit</b><br>Polyvinyl chloride (PVC) is by far the most 
widely used jacketing material for electrical insulation, thanks to 
inherent benefits such as dry and wet electrical performance, 
flexibility, long life, fire retardance, cold temperature resistance, 
chemical resistance, and ruggedness. But in a fire, PVC releases fumes 
collectively called halogens that include hydrogen chloride, hydrogen 
fluoride, and hydrogen bromide gases, as well as other deadly combustion
 products. Electri-Flex

Electri-Flex

LSZH Conduit
Polyvinyl chloride (PVC) is by far the most widely used jacketing material for electrical insulation, thanks to inherent benefits such as dry and wet electrical performance, flexibility, long life, fire retardance, cold temperature resistance, chemical resistance, and ruggedness. But in a fire, PVC releases fumes collectively called halogens that include hydrogen chloride, hydrogen fluoride, and hydrogen bromide gases, as well as other deadly combustion products.

As a result, where smoke from fire presents an increased hazard to people, the trend is toward the use of LSZH insulation and conduit. Typical examples include aircraft, ships, recreational vehicles, tunnels, mass transit vehicles, elevators, and other confined spaces. LSZH reduces the amount of smoke and flame spread, which can allow people more time to easily escape areas of fire.

LSZH jacketing material has only relatively recently come into widespread use in North America and customer demand for it is rapidly increasing, as it virtually eliminates the release of the toxic gases found in PVC products. In some cases, PVC-jacketed conduit is no longer allowed for electrical construction by building codes and in locations where low smoke and low flame spread are stated requirements.

After many years, Electri-Flex Company began manufacturing and developing LSZH-jacketed conduits and today offers six halogen-free product lines (Types ZHLA, CEA, ACEA, ATX, Corrlok, and Shielding) in a broad array of variations dedicated to specific applications. Its proprietary formulation of thermoplastic polyurethane combines low smoke, flame retardation, and toxicity generation characteristics, virtually eliminating hydrogen chloride, hydrogen fluoride, and hydrogen bromide gases during a fire. Third-party testing of the polyurethane compound used by Electri-Flex for flexible jacketing material demonstrated that performance is far better than required by industry-accepted standards.

Halogen-Free Product Lines
Type ZHLA is made with a polyurethane jacketing and a core of hot-dipped galvanized steel that provide a working temperature range of -40° C to +80° C in air, +60° C when wet, and +70° C in oil. It is UL listed, CSA certified, and RoHS and WEEE compliant.

Type CEA has a polyurethane jacket and corrosion-resistant plated steel core and is designed for applications such as wiring harnesses within and under passenger train cars, as well as subways, tunnels, and enclosed public areas. Type ACEA is similar to Type CEA but has a core of an aluminum alloy strip that reduces its weight to half that of Type CEA while also providing flame resistance and limited smoke characteristics. Each has a working temperature range of -40° to +80° C and, although not UL listed, is RoHS and WEEE compliant.

Type ATX refers to the non-UL conduit line capable of withstanding extreme temperature ranges. This conduit combines the flexibility of the standard LT core with the advantage of a thermoplastic rubber jacket that is unaffected by temperature extremes and contains zero halogens. The material has a flammability rating of UL 94-HB and is UV stabilized. The conduit’s working temperature range spans from -60°C to 150°C, intermitting to 165°C.

Type CLFR is a part of the Corrlok system of corrugated flexible tubing made from a flame-retardant Nylon 6 compound that provides low flame spread and smoke as well as limited toxic characteristics.

The company also offers the option of halogen-free-jacketed shielding conduits in the HFSLA, HFEMS, and HFEMCS families with a polyurethane jacket extruded over them that are better suited than standard conduits for data transmission circuits that require EMI/RFI shielding protection and are in a confined space such as a data center plenum floor.


Photo courtesy of Electri-Flex