The local AHJ has asked if any part of the system piping will be routed below ground and has requested details on required corrosion protection system, trenching, and backfill. They cite the following sections of NFPA2: 7.1.15.3.2 Contact with Earth. 7.1.15.3.2.1 Gas piping in contact with earth or other material that could corrode the piping shall be protected against corrosion in an approved manner. "55:7.1.17.2" 7.1.15.3.2.2 When cathodic protection is provided, it shall be in accordance with 7.1.18. "55:7.1.17.2.1" 7.1.15.3.3 Underground piping shall be installed on at least 6 in. (150 mm) of well-compacted bedding material. "30:27.6.5.1" 7.1.15.3.4 In areas subject to vehicle traffic, the pipe trench shall be deep enough to permit a cover of at least 18 in. (450 mm) of well-compacted backfill material and pavement. "30:27.6.5.2" 7.1.15.3.5 In paved areas where a minimum 2 in. (50 mm) of asphalt is used, backfill between the pipe and the asphalt shall be permitted to be reduced to 8 in. (200 mm) minimum. "30:27.6.5.3" The instrument, air and hydrogen lines are stainless steel and will be installed in a PVC sleeve. In the Panel’s experience, is this adequate cathodic protection for the lines?