Extension tube malleable Zn

  Datasheet (PDF)

The Georg Fischer 526 malleable cast iron galvanised extension tube is a heavy-duty threaded fitting engineered to provide dependable linear extension and axial spacing across commercial, utility, and industrial piping networks. Fabricated from decarburised annealed whiteheart malleable cast iron grade EN-GJMW-400-5 in compliance with EN 10242 Design Symbol A, the component offers exceptional mechanical strength, resistance to high internal stresses, and long-term dimensional stability. Designed with a taper external thread R and a parallel internal thread Rp conforming to EN 10226-1 and ISO 7-1 jointing standards, the extension tube establishes an interlocking metal-to-metal sealing geometry that achieves complete pressure tightness when coupled with appropriate thread sealing media. The fitting features a high-purity hot-dip galvanised protective zinc layer formed directly over bonded iron-zinc alloy layers, ensuring high corrosion resistance, preventing internal encrustation, and fully complying with hygiene standards for drinking water distribution installations. With an operating envelope rated for continuous working pressures of 25 bar from -20 degrees Celsius to 120 degrees Celsius, and up to 20 bar at elevated temperatures of 300 degrees Celsius, this extension tube delivers dependable flow continuity in domestic drinking water systems, hydronic heating and cooling loops, compressed air installations, gas services, and industrial process piping. Its precision-engineered axial length and uniform thread geometry facilitate accurate alignment, simplifying on-site positioning and prefabrication where fittings, terminal valves, or pipe sections require precise extension without superfluous adaptors.