I'm not quite finished with my own similar propane installation, but I have finished all of the investigation and research, done more than half of it, and watched that operate according to my expectations. When it did not meet my expectations, I determine what was wrong and fixed it. I am no kind of expert, but I have learned quite a bit along the way. I'll mention a few things worth passing along:
* Regarding installing gas in any kind of a mobile application, there is no consistent answer about anything from anybody, accept the fact that propane is flammable. This includes everybody from your neighbor next door to plumbers and professional propane technicians. Everyone will give you their opinion, but there are precious few incontrovertible facts to back any of that up. In the end, you have to decide what seems to make sense for you and just try to avoid the obviously stupid things. But even which things might be on that list are contentious.
* BradKW made a good point about black iron pipe, but what he didn't mention is that the specialized equipment to cut and thread that pipe exists in almost every home improvement store. If you buy the pipe from them, they will cut and thread it for you, normally for free. I had quite a bit of that done a couple months ago. I used black iron pipe in unrelated projects, and used it in my propane project to cross from a non-living area through an interior wall into the living area. For several reasons it was the best choice for that portion the propane installation:
Strength to resist any abrasions coming through the wall and potential damage resulting from vibrations during travel; commonly available and relatively inexpensive; a large assortment of commonly available parts to turn corners and change sizes as needed; connections made with nothing more complicated than pipe wrenches and gas tape or goop; and finally, it is a preferred construction material for gas installations according to many sources.
* The trickier and more contentious parts are the beginning and ending sections. Namely, the part from the propane tank to the beginning of the black iron section, and then the part from the other end of the black iron section to your propane device, such as a camp stove or Buddy Heater.
You cannot use anything rigid to do that job. That leaves you with three basic choices: The flexible stainless steel gas tubing like Brad was talking about, copper, and black rubber hose similar to the type that the Mr. Heater company sells. All of those have pros and cons.
The flexible stainless steel tubing is not the panacea that it seems to be when you first look at it. According to people who do these installations in homes, that tubing is intended for a one-time installation and very seldom movement, such as pulling a gas appliance away from the wall once a year to sweep behind it. It is not designed for constant movement. People who know the most about that material are concerned about metal fatigue and eventual leaks in a situation where it would be moving or vibrating a lot. Although I first wanted to use that for the two ends of my installation, I decided against it for those reasons.
I considered copper, but shied away from it due to cost and the specialized tools and skill to make the connections. That might have turned out to be not such a big deal, but I decided to avoid it and do something more straightforward and within my control.
After much discussion and consideration of all of these different propane carrying media, I chose to get high pressure black rubber hoses custom made for those two sections. Those hoses were created by gas technicians at a propane gas company. Although it sounds like a highly specialized thing, it really is not for those people. They make hoses like that all the time. You just tell them what you want and they make it. Mine were made while I waited in the office.
I'm sure questions will get raised about rubber. On one hand, people say it degrades. Apparently it does, but it can take many years to degrade. I've had a greater number of people tell me they've had a rubber hose connected for many years and had no problems. And if you have a filter on your buddy heater and check the hoses periodically for leaks, it would help reduce or eliminate any real problems.
The great benefits of using rubber hoses are flexibility to make your connections; any lengths you desire within reason; any connector on any end of the hose that you need; speed of obtaining it; they do exactly what you want them to do; and relatively high durability.
I also got pretty deep into learning about gas valves for this installation, but I'll leave that for another day.
In case you haven't seen them yet, there are other threads in here called propane hoses and connectors, and one on buying propane tanks. They're worth reading.
Tom
