Municipal water pipe has always been exclusively the preserve of ductile iron and concrete. Now Krah Pipe Systems in Greenwood, S.C., has set up the world's first plant to produce three-layer, glass-reinforced, spiral-wound HDPE pressure pipe in diameters from 18 to 120 in. for municipal water. The plant started up in October and is currently producing pipe for Europe (Krah recently received ISO/AWI 29561 test approval from Becetel in Belgium). The parent company, Krah AG in Schutzbach, Germany, is a pipe extrusion machinery supplier. A second line using the glass-reinforced HDPE composite pipe technology has just started up at Firat Plastik in Turkey. Krah's composite pipe system feeds HDPE, coupling agent, and 20% chopped glass into a co-rotating twin-screw compounder, which feeds a short single-screw extruder. The latter produces a continuous strip that is wound in a spiral around a rotating mandrel. The inner and outer layers of the pipe are unfilled HDPE containing UV stabilizer. Two wires can be embedded in the pipe bells and fittings to allow joining by electrofusion. (864) 223-0592 . www.krahnorthamerica.com
Editor PickSizing the Barrier Gap
Here’s a less complex way to properly size the barrier gap for barrier screws.