The Coming of Flexable Lines - Propane, Gas, and hydraulic

I don't think there's a trend at all. Seems to be mix and match and more weight driven and routing related than anything I bet. Last camper was an HTT and all LP lines were soft copper with the exception of the pigtail for the low pressure BBQ. New camper, same manufacturer, higher and heavier line - 3/4" black pipe front to rear. Quick connect right off the pipe for the grill. HWH and furnace are fed from very short soft copper runs teed off the black pipe. Fridge in the slide-out is the only appliance with a true LP flex line.

Actually, flexible line is cheaper, when you consider the fittings, hangers, possibility of leaks and then having to dismantle, and installation labor. It is just as good if not better than black gas pipe, as long as you don't damage it, and that is fairly hard to do. Observe the particular manufacturers bend radius requirements, and you don't need 45 and 90 fittings to make a turn.

If the installer has a fitting leak when pressure testing, he cuts the line at the fitting, reinstall the line and new clamp on the fitting, and squeezes on the clamp. Less than a minute. Try that with hard line. Some gas line still require compression termination fittings, but it still much faster and thus cheaper than metal pipe.

Have you looked at the new MHs? Many have no propane tanks. Aqua hot and all electric.

I don't think it would be cost cutting since the solid pipe used on my toyhauler is probably cheaper than any flexible line of the same length.

humm...both my previous trailers (2007 and 2011)had metal propane lines running under the coach and only the end connections to tanks and appliances were flexible...my neighbor's RVs are all a few years old and have solid propane lines running under the rig and end connections are flexible...

Coulda fooled me. I thought they were all flexable for many years already, in fact I know they were.