Can Gas Lines Run Inside Wall

Would it be possible, or advisable, to run a line up the side wall, hang it under the fascia (flat roof), and then down the far side?

Can Gas Lines Run Inside Wall. The gas line comes to our meter at one end of the house, and the owner wants to have a gas burning insert in the fireplace at the other end of the house, 50 so many obstacles! In lieu of replacing the pipe, can i use a smaller flex gas line, like 3/4 or 1/2, and run it inside the 1 black pipe?

flexible gas line dangers
flexible gas line dangers from www.askthebuilder.com
The disadvantage of early indoor fire pits was that they produced toxic and/or irritating smoke inside the dwelling. Start date apr 13, 2009. I hope to see the gas line go from the utility room, under the foyer, up through a second floor closet into the attic, and then over to the far corner, to come down the outside of the fireplace wall.

More collisions mean more force, so the pressure.

Each time they collide with the walls they exert a force on them. Remember you can break glass. Gas pressure increases with temperature. Would it be possible, or advisable, to run a line up the side wall, hang it under the fascia (flat roof), and then down the far side?