Natural Gas work is not a job for the weekend warrior. The inspector never tells you what material is correct for any job. His duty is to inspect that all work was performed to code. You are not qualified to do this work and he is letting you know that without bruising your ego.So take the hint and call a Licensed Plumbing Contractor to run this gas service for you. Bill The Local Plumber Tustin, California http://www.TheLocalPlumber.com