Minnesota Administrative Rules
Agency 151 - Labor and Industry Department
Chapter 1346 - MINNESOTA MECHANICAL AND FUEL GAS CODES
MINNESOTA FUEL GAS COD
Part 1346.5404 - SECTION 403 (IFGC) PIPING MATERIALS

404.6 Underground penetrations prohibited. Gas piping shall not penetrate building foundation walls at any point below grade. Gas piping shall enter and exit a building at a point above grade and the annular space between the pipe and the wall shall be sealed. If necessary due to structural conditions, underground piping may be installed with prior approval from the building official.

404.14 Piping underground beneath buildings. Piping installed underground beneath buildings is prohibited except where the piping is encased in a conduit of wrought iron, plastic pipe, or steel pipe designed to withstand the superimposed loads and with prior approval from the building official. Such conduit shall extend into an occupiable portion of the building and, at the point where the conduit terminates in the building, the space between the conduit and the gas piping shall be sealed to prevent the possible entrance of any gas leakage. Where the end sealing is capable of withstanding the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such conduit shall extend not less than 4 inches (102 mm) outside the building, shall be vented above grade to the outdoors, and shall be installed so as to prevent the entrance of water and insects. Such conduit shall be identified with a yellow label marked "Gas" in black letters, spaced at intervals not exceeding 5 feet (1,524 mm), and shall be located a minimum of 6 inches (152 mm) below the bottom of the concrete floor. The conduit shall be protected from corrosion in accordance with IFGC section 404.11.