i just bought an older house in NC. that has natural gas for stove, water heater and furnace. The feed line starts out as black iron then tees off to different areas. Off each tee they have run soft cooper. 15+ft to furnace, 10+ ft to stove and 3 ft to water heater. Shouldn’t this be in black iron, then a short flex line for final connection? My understanding is a number of years ago the home was converted from propane to natural gas. p.s. there is no shut off valves except for at the meter. Thank you Larry!!!!