In the post 3 Systems of butt welding according ISO 21307, we showed the differences that there are between them, and even we calculated the butt welding parameters of a pipe of PE100 DN 500 SDR 11, and we concluded that the system that needs less time to perform the welding is the high-pressure system, that’s why we consider it the best system to optimize the performance of an installation of PE pipes of big diameters, equal or higher to DN [...]