Casing Then Foam Insulation Line DN90-315 mm Overview Secondary network pipe is not made in campaigns of one size. A plant supplying a city district or a housing scheme runs 32, 50, 75, 110 and 160 mm in the same week, often in batches of twenty pipes. A one-shot line is chosen here because casing extrusion, pipe insertion and foaming sit on one frame: the casing is cut to length and immediately married to the steel pipe, so there is no casing store, no double handling and no