Does anybody have any experience with direct bury insulated steam line? My application is a 4" X Sch 40 steam line at 300 psig and 430 degrees F. The bury length of the line is approximately 450 feet. The line has a 410 foot radius, 53 degree arc. My intention is to insulate the line with 3" of FOAM GLAS (which is fairly rigid) insulation. The insulation will be covered with SS cladding. The bury length of the line is not long enough to fully develop a virtual anchor. I am aware that I can used Ultra-Therm (aka Ricwil) pre-insulated pipe but I would like to explore the possibility of direct bury.