I am using black steel pipe for a gas line and want to know if I can use galvanized steel to tie in an exterior line.

The reason for Black Iron Pipe rather than Galv. Is; Galvanized Pipe will flake and the flakes can plug your appliance burner. It is my understanding that Gas Piping Codes require the use of Black Iron Pipes and fittings, Thanks.

John

Well explained by John in the above post.

If you are using only short nipple to connect new pipe with existing - like Left-to-Right nipple and coupling, go ahead and use it. It will not plug your appliances.

Hope that helps

Milo