Polyethylene pipes are widely used for the construction of gas distribution networks. The disadvantage of pipes is their low mechanical strength. When crossing various artificial obstacles in pipes, unacceptable stresses may arise, causing destruction along the pipe body. To make a decision on the installation of a casing in such areas, it is necessary to determine the stability criteria for the circular cross-section of polyethylene gas pipelines. The article reveals that of the two equations proposed by SP 42-103-2003 for the critical value of external pressure of polyethylene gas pipelines, in practice only one can be used, for which the criterion value is always minimal.
Keywords: polyethylene gas pipelines, dynamic load, stability of the circular cross-section, external pressure