The lines under the deck are 2" steel gas pipe that has the yellow plastic coating, you then wrap any of the fittings with this special 10 mil tape so they are protected also.
The main supply from the house will be the plastic line you are talking about so there will need to be a tracer wire attached to it. There will only be two fittings required, one being the riser by the gas meter, the other a coupling that will attach to the 2" steel gas pipe. from what the supplier told me these are "friction" fitting that all you do is push them on to the end of the plastic and some kind of O-ring will seal it. Seems strange to me but I guess since the pressure is so low it works. The fittings are made of steel. The material to run 170' of the 2" plastic are approx $450.00, digging the ditch 18" deep min will be the hard part, at least we have fairly soft earth.