I ran this post in Residential HVAC and got only one answer which said to post it here. Thank you.

What type metal tubing should I hear a contractor recommend to me when he visits on Thursday, May 26? Stainless? Corrugated Stainless? or Copper? There must be advantages and disadvantages to each.

This forum was a great help to me two years ago when I replaced the A/C and natural gas furnace in my house. Now, I am getting a gas fireplace insert to replace the wood burning insert that I have used every year since 1982 in a masonry fireplace. The house is a two story with split foyer.

For a 70 to 90 foot run, a couple insert sales people have suggested that I might have to get Washington Gas here to convert to split meter. That lets us us a small diameter line for 2 psi.

A problem is that the fireplace is in the opposite corner of the house from the gas meter and utility room. 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. Should the tubing run through conduit anywhere along the way?

By the way those same salesmen are suggesting going around the outside of the house. Ugly??

I've just read through parts of the International Gas Fuel Code. I suspect that iron pipe would be harder to install than tubing, can't use aluminum outdoors, and can't use plastic indoors.

Thank you.
Al