We had an 80 megawatt combustion turbine at a place I worked. It would run on oil or natural gas. We had to call our pipeline supplier an hour or so before we started it, so they could start some pumps. It was a 12” line at a couple hundred psi as I recall. It had no smell either, we added the mercaptan at little station where the pipe exited the earth and then through a couple skids for regulation, metering, and shut off, then into the turbine engine. The plant was surrounded by a levee to hold back the Missouri during high water, the place was an island during the 1993 flood. The unscented gas always seemed like it could fill our levee pretty fast before we would know it, but it never did…….yet.
I’ve done a bit of contractor work at a refinery , there were dudes there welding a hot tap fitting to a 24” or so pipe with gasoline flowing through it. I had to ask…..they said the flow keeps it cool enough to be safe?