I need help: can butt-weld flanges be used for PE pipe flanges?
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Seeking expert advice: For pressure pipelines in GC1, carbon-lined PE pipes are to be used. How should the flanges be selected? Is it acceptable to use PN25 butt-welded flanges as required? Since lining requires soft gaskets, and according to the specifications, soft gaskets should be used for PN25 flanges, convex-concave flanges need to be employed – how can this requirement be met then? The standards for lined pipes recommend the use of PL flanges, but PL flanges seem inappropriate for highly toxic fluids such as GC1.
When selecting soft gaskets for PN25 flanges in accordance with the specifications, concave-convex flanges are required. Which specification mandates this?
Can pipes with a carbon steel lining and PE coating be used at a pressure of PN25? PN16 is generally sufficient. Additionally, gaskets are usually not used, as there is a flange; it is said that using gaskets actually leads to leaks in practice. These pipe flanges are all pre-fabricated, and butt-welded flanges can be used.