Method of assembling a vacuum insulated piping run for conducting a cryogenic fluid in which piping sections are produced in a first location and then assembled in a second location into a piping run.Each of the piping sections incorporates an outer cylindrical casing and an inner pipe for transport of the cryogenic fluid to form an inner annular region for containing insulation that can be radiation shield insulation and aerogel blankets. The piping sections are joined by welding the ends of the inner pipes together and then joining the outer cylindrical casing by a shell-like section. Points of connections are tested by vacuum testing techniques as each of the connections is made. Thereafter, the annular region is purged with a condensable gas such as carbon dioxide and subjected to a subatmospheric pressure.