Produksjonsteknikk

This document defines the content of the INSTA 2072 series of documents as well as the composition of the welding quality monitoring methods proposed to ensure dependable butt fusion quality in the field. This recommendation consists of stages and groups referring to their own standards. Annex A shows an overview of the monitoring methods for butt fusion of polyethylene and polypropylene pipelines. The monitoring methods are classified into groups A, B and C according to the scale and ex post controls. Stages 1, 2 and 6 are mentioned only to provide background information and are not part of the welding documentation. Annex A gives a condensed view of the stages and parts in this document series. Selection of the monitoring method shall take into account the application field and operating temperature of the pipeline, as well as the population density and rating of the area where the pipeline is installed.

This procedure defines butt fusion as a joining method for connecting pipe to pipe or pipe to pipe fittings. Butt fusion is commonly used e.g. for PE or PP pipes and pipe fittings. These instructions describe principles and are not intended to guarantee compatibility of different polyethylene or polypropylene grades. Appendix A provides indicative welding parameters. This document describes a welding method and parameters that have been found suitable for conditions in the Nordic countries (S, FIN, N, DK), for temperatures down to -10°C and a wall thickness of not more than 70mm. For lower temperatures and thicker pipes, a verification welding is needed. Please refer to instructions from pipe and/or welding machine suppliers. Investigations into lower allowable ambient temperatures for welding are ongoing. Other similar welding documents [1], [2], [3], [4], [5], [6] are found in the bibliography. Pipes with peelable layers are not covered in this document. Please refer to pipe supplier’s recommendations.