The development of recommendations for the reconstruction of steel gas networks by dragging polyethylene pipes

Abstract

The recommendations are developed for the reconstruction of underground steel pipelines with the use of polyethylene pipes. It is found that in case of dragging polyethylene pipes with diameters that are recommended by the normative document the State Construction Standard (ДБН В.2.5-41:2009) the throughput lowers from 60% to 95% depending on the diameter of the steel pipeline when the operating pressure doesn’t change. The operating pressure in the gas supply system is offered to be changed from the low one to the medium in order to preserve the throughput during the reconstruction. The methods and software are developed in order to calculate the value of the difference of squares of the initial and final pressure per one length unit of the medium pressure polyethylene pipeline when the value of the hydraulic tilt in the low pressure steel gas network is known and this will guarantee the throughput preservation and the implementation of the normative document the State Construction Standard (ДБН В.2.5-41:2009) that deals with the choice of the pipe diameter. Based on the research the analytical dependencies and the graphical nomographs have been obtained in order to determine the necessary geometrical and regime parameters of the medium pressure gas pipeline for replacing the steel low pressure gas pipeline on condition of the full project throughput preservation.