Structural integrity of the pipeline system on the installation of nuclear power plant is a construction system of large and complex. This piping system must be able to wtihstand all loads that work well statistic and dynamic loads. The ability of piping system to withstand the loading of work so as not to cause the failure known as a piping system flexibility, the location and span of supports must be determined first before analysing. By optimizing the span of supports will save construction coats. The equation for calculating the maximum span based on the ASMER B 31.1 will be described in this paper.