HFFR

HFFR (halogen free flame retardant) is a halogen-free flame retardant polyolefin compound that replaces PVC in cable insulation and sheathing. The industry also calls it LSZH, LS0H or LSFH. More than half of its weight is a mineral flame retardant filler — aluminium trihydroxide or magnesium dihydroxide — dispersed in a polyolefin carrier resin. At high temperature that filler releases its bound water endothermically: it cools the flame zone, dilutes the combustible gases with steam and leaves a protective oxide layer on the surface.

What separates it from halogenated materials is what happens during a fire. PVC releases hydrochloric acid and dense smoke; the gas hinders evacuation and, combined with moisture, corrodes electronic equipment. Since HFFR contains no halogen, no acid gas forms and smoke density stays low. In tunnel, metro, hospital, airport, marine and high-rise projects this is now a specification requirement.

The high filler loading naturally stiffens the compound; the real engineering is holding elongation at break, tear strength and line speed while keeping the flame retardancy. The portfolio carries separate grades for insulation and sheathing, plus dedicated versions for thin-wall cables, oil resistance, −50 °C cold flexibility, anti-dripping and high line speeds. Limiting oxygen index typically runs 32–47%, tensile strength 8–14 MPa and elongation at break 130–650%.