Malleable iron plug

  Datasheet (PDF)

The Georg Fischer malleable cast iron plug 291 plain ISO/EN T8 provides a robust, permanent or serviceable end closure for female-threaded branch outlets, fitting branches, and pipeline terminations across industrial, municipal, and commercial installations. Engineered in strict accordance with EN 10242 and ISO 49 design symbol T8, the component features a precision-machined external taper jointing thread R compliant with EN 10226-1 and ISO 7-1. This taper profile achieves pressure-tight thread sealing through progressive metal-to-metal contact against mating parallel internal threads (Rp), requiring minimal thread jointing sealant to deliver total hermetic containment under hydrostatic and pneumatic stresses. The solid geometry incorporates an integral external square drive head across standard metric flat dimensions, granting positive tool engagement for controlled torque application with conventional open-ended or adjustable pipe wrenches even in tight clearance spaces. Standard fitting bodies are manufactured from whiteheart decarburised annealed malleable cast iron meeting Design Symbol A criteria, offering outstanding elongation, resistance to mechanical shock, structural tensile integrity, and dimensional stability under continuous pressure cycles. Smaller dimensions from one-eighth to three-eighths inch are produced from high-grade steel with an electroplated zinc coating, whereas standard malleable sizes receive a dense hot-dip galvanised finish exceeding 500 grams per square meter, forming protective iron-zinc alloy layers that reliably prevent external oxidation and internal scale formation in potable water, cooling loops, hydronic heating, compressed air, and gas distribution systems. The component sustains continuous thermal cycles ranging from minus 20 degrees Celsius up to 120 degrees Celsius at a maximum permissible working pressure of 25 bar, and up to 300 degrees Celsius at 20 bar, ensuring exceptional operational longevity across rigorous process media.