Regulations of Connecticut State Agencies
Main carrier pipe shall be laid and maintained at least twenty-four inches below the surface of the soil. Where there is interference with other subsurface structures, the pipe shall be laid a distance of not less than twelve inches away from such structures. Any interfering structure which provides a space in which an explosive atmosphere might accumulate in the event of a leak shall be avoided where possible and preference shall be given to crossing over rather than under such structures. A metalic protective shield of a thickness at least as great as the pipe shall be provided or the pipe shall be cased in the event of such a crossing.