摘要：The article deals with topical issues at the pre-investment stage of project design to justify decisions on the feasibility of further investment and the transition to the next stage of design - the development of project documentation. At the pre-project stage, there is often a situation when the parameters of structures have not yet been determined, and capital investments must be evaluated. Methodological approaches to determining the cost of gasification facilities and the estimated model of cost calculations at the stage of investment justification with the help of enlarged indicators that improve the accuracy and validity of calculations at the stage of pre-design studies are substantiated. It is shown that the enlarged indicators used at the stage of investment justification form the regulatory basis for determining the cost of gasification facilities, for estimating capital costs, as well as for evaluating the effectiveness of investments in the selection of project options. The object of the study adopted electrically welded steel pipes and polyethylene pipes for gas pipelines. Evaluation and forecasting of the cost of gas distribution systems in the article are proposed using regression models depending on time and diameter of the pipe. The regression dependences of the cost of steel and polyethylene pipes of all standard sizes and confidence intervals for the cost of pipes allow to estimate also possible errors of the forecast cost estimation.
