I'm installing a gas (wood)stove in my vacation cabin. The existing natural gas piping runs around the outside of the brick and there isn't a single union anywhere. In order to tee into the pipe I was going to saw into the pipe where I want to install the tee but I'm not sure how to do it safely. Best idea I can come up with is to turn off the gas at the meter & disconnect it there. Also disconnect at my water heater which is the farthest termination point. Use compressor to flow air through the pipe to hopefully eliminate the explosion hazard and then saw the pipe & proceed with the plumbing. Sound like the best way to do it? Also--is it OK to use a union outdoors? If not that would explain why there aren't any.