Tom, If that CSST is less than 6 feet above grade it also has to be protected from mechanical damage (in a conduit or such) if its trac pipe or gas-tite. It also does require sleeving through masonry, be sealed water-tight both sides and is required to be bonded. If that csst is connected to a gas fired insert (moveable appliance) and not a fireplace it has to terminate with an approved termination fitting securely attached to the inside of that masonry fireplace.Then a gas-cock and an approved flex connector with the tag attached! Hope this helps. I certify installers of Trac-Pipe and Gas-Tite in New England and NY but not Ward-Felx. Jack