Gas Line Installation

[Jakob R New York]

Hi there!

I am converting a 8.5x20 Aluminum Car Hauler into a mobile dwelling and have some questions about running gas lines underneath the trailer for our propane system.

I have seen a lot of conflicting information regarding the type of piping to use in moveable dwellings as there is an obvious factor of movement which makes selection particularly important.

My understanding is that in most RV's, either iron or copper piping is used for the propane gas lines. I have read visceral reactions to using steel proflex (CSST) in moveable dwellings.

The proflex material looks very appealing in terms of simplicity. I'm curious why it is such a problem for moveable dwellings?

I was curious if someone with experience installing gas lines could inform me of the appropriate type of piping to use and the associated considerations:

1.) Rules for junction points (fittings etc). (Should you only use a single line from source to appliance? Or can you have a mainline that branches to each appliance?)

2.) Securing/fastening the piping to trailer frame. (Should there be some intentional movement allowed to prevent cracking over time?)

3.) Any advice about bending the piping (in the case of copper).

I like what I have read thus far about semi flexible copper piping however, I am a bit concerned that since all of the piping will be run underneath the car hauler (secured to the chassis/frame) that there is some level of risk for puncture/damage to the exposed piping itself.

Perhaps there is some sort of protective material that I could run the copper piping through to enhance its durability?

Any additional advice would be greatly appreciated if you have any other anecdotes not mentioned in the questions above concerning running new gas lines in a mobile dwelling.

I greatly appreciate all of your wisdom and kindness!

Cheers,
Jakob

[AC0GV]

Originally Posted by Jakob R New York

Hi there!

I have seen a lot of conflicting information regarding the type of piping to use in moveable dwellings as there is an obvious factor of movement which makes selection particularly important. Cheers,
Jakob

If you use black pipe for the main line and Teflon thread tape, use gas (yellow) tape. Also my old trailers used black pipe for the main run and then copper to the appliance with the necessary bends it it.

[Raspy]

As you mentioned, some RV manufacturers use iron pipe, or more specifically, schedule 40 black pipe. I just ran a new main line on my trailer and used 1/2" sch 40 galvanized pipe. Galvanized is slightly more expensive, but perfectly compatible with propane and is much more corrosion resistant. I'm sure trailer manufacturers use black pipe simply because it is cheaper. I mounted it to the steel frame with steel pipe hangars. Where possible, I bent it to fit the undercarraige or to get it up higher between frame rails, instead of just adding more fittings and short nipples. Then converted it back to rubber propane hose, with brass flare style fittings before entering the trailer. These rubber style propane pigtail hoses have a female thread end that attaches to a male brass tapered fitting on the pipe. The pipe fitting for each drop is a brass male propane X 1/2" male pipe thread fitting that screws into a 1/2" galvanized Tee. The Tees connect sections of the main pipe. At the end of the run, a female brass pipe fitting screws onto the end of the pipe for your final drop. You can put tees along the run to make drops for appliances, then run propane rubber hoses, or copper tubes, up into the trailer to connect to your appliances. I think the rubber style hoses are better because you don't have to flare and they won't kink like copper. 1/2" pipe is large enough to run a water heater, cook stove and the furnace. You can look up a gas pipe capacity chart to verify the sizing of the pipe, if you'd like. 1/2" galvanized pipe is very durable against road damage, is corrosion resistant, and can be bent to fit gradual turns or body lines. Connecting the flexible pigtails outside the trailer is safer than making more connections inside the trailer.

[mary and bob]

When I worked for a fuel company and did residential propane installation we never used galvanized pipe. I did a quick google search and most results said not to use it because the galvanization could flake off and plug regulators or appliance offices. Do a search and see what you find.

[AC0GV]

Originally Posted by mary and bob

When I worked for a fuel company and did residential propane installation we never used galvanized pipe. I did a quick google search and most results said not to use it because the galvanization could flake off and plug regulators or appliance offices. Do a search and see what you find.

Unless a recent edition changed it the National Fuel Gas Code does not prohibit galvanized piping in gas installations. Yes, there is a concern about zinc flaking off, but no more of a concern than copper sulphite from reactions between impurities in the fuel and copper in the system.

[Raspy]

Originally Posted by mary and bob

When I worked for a fuel company and did residential propane installation we never used galvanized pipe. I did a quick google search and most results said not to use it because the galvanization could flake off and plug regulators or appliance offices. Do a search and see what you find.

I don't think this is as much of a concern as rust in black pipe clogging orifices. Black pipe is OK, but it should be clean and dry inside before installation. Either way, I like the steel pipe idea for its durability. Galvanizing cannot flake off unless it was done incorrectly.

[Jakob R New York]

Thank you for your responses!

So to the best of my understanding, sch 40 black galvanized steel might be questionable however - it appears to be what is used in most commercial RV setups, also known as "black pipe"?

The other most common material appears to be copper piping for both the main line and the branches.

My largest concern is durability since the majority of the piping will be run underneath the car hauler trailer.

If I went the route of copper piping, I have read that copper type L or K may be used.

I do like what Raspy mentioned about using only propane rated hose for the branches which lead directly to the appliance inside my cargo trailer.

The question then becomes if we go with copper as the main line, are there any implications to securing it to the chassis to ensure that there is no friction damage? Using rubber grommets to affix the line to the under surface of the trailer perhaps?

I also have some concern about kinks in the copper piping and for that reason imagine that it makes the most sense to avoid bending as much as possible.

Would you rather take the chance of bending the pipe or use a 90 degree connection if a change of direction was warranted?

It seems there are trade offs to each option of course.

Furthermore, logically it makes sense to protect the copper piping in an additional manner as it is directly exposed to whatever it comes into contact with as I am driving down the road (rocks etc).

However, if I wrapped the copper piping in, say a clear braided hose - it would provide some additional durability but perhaps conceal any leaks to the copper piping.

Once again, trade offs.

Any thoughts would be much appreciated!

Thank you all again for your input!

Cheers,
Jakob

[Raspy]

Jakob,

The steel pipe is either black, or galvanized. It is not black galvanized.

If you use copper for the main runs, it will need to be flared, which probably rules out K and is a lot harder to do unless you have good quality tools and know how to use them. Every 90 degree copper fitting will need to be flared too. Copper will likely be more expensive, with no real benefit.

Coming up through the floor and connecting to an appliance will require a lot of precise bends if you use copper, but rubber flex hose is super easy to install. Sometimes it is really the only way, as in needing to pull out the stove to make the connection.

You can slip the copper into a piece of garden hose for limited protection, but not much mechanical protection. And it won't help at the tees. Any leaks in the copper system will be at the flares or fittings, not likely in the middle of the tube.

If you have to pass under the frame, the steel pipe is probably the best bet for mechanical damage resistance.

[Jakob R New York]

Originally Posted by Raspy

Jakob,

The steel pipe is either black, or galvanized. It is not black galvanized.

If you use copper for the main runs, it will need to be flared, which probably rules out K and is a lot harder to do unless you have good quality tools and know how to use them. Every 90 degree copper fitting will need to be flared too. Copper will likely be more expensive, with no real benefit.

Coming up through the floor and connecting to an appliance will require a lot of precise bends if you use copper, but rubber flex hose is super easy to install. Sometimes it is really the only way, as in needing to pull out the stove to make the connection.

You can slip the copper into a piece of garden hose for limited protection, but not much mechanical protection. And it won't help at the tees. Any leaks in the copper system will be at the flares or fittings, not likely in the middle of the tube.

If you have to pass under the frame, the steel pipe is probably the best bet for mechanical damage resistance.

Ah this makes sense! Thank you for the clarification on that. So then perhaps going with the sch 40 galvanized would be the best option to avoid having to flare. I'm assuming the galvanized would just use threaded fittings in which case I could use those and wrap with teflon tape.

I really like your idea of using a flex hose for connecting from the main line to the appliances. Seems simple and would not have to have worry about flare fittings.

So assuming I went galvanized, I would use the flex hose to make the connection between the propane tank and the beginning of the main line and then use flex hose again at each appliance?

[Raspy]

Originally Posted by Jakob R New York

So assuming I went galvanized, I would use the flex hose to make the connection between the propane tank and the beginning of the main line and then use flex hose again at each appliance?

Yes.

Since you don't have experience with this, I suggest you get help from a plumber that does have this kind of experience.

[JoelInTexas]

Cutting and flaring copper is easier than cutting, threading and joining iron pipe.

Copper is flexible, which means that it's easier to route through crowded areas, it typically requires fewer joints, and the ability to bend it makes it more forgiving of joint locations.

There is absolutely no way I would consider installing iron pipe instead of copper.

[CharlesinGA]

Originally Posted by AC0GV

Unless a recent edition changed it the National Fuel Gas Code does not prohibit galvanized piping in gas installations. Yes, there is a concern about zinc flaking off, but no more of a concern than copper sulphite from reactions between impurities in the fuel and copper in the system.

During a hour long phone discussion about the Winntec propane regulator issue, with a person who has over 30 years of experience investigating RV fires for a major RV appliance manufacturer, and a member of the National Fire Protection Assn, he did state that NFPA no longer allows black iron (or should I say, rigid) pipe to be used in RV propane installations. He really didn't know why as he had never seen a problem with it, but the rule change has driven RV manufacturers to install either all soft copper tubing, or rubber hose. RV manufacturers have to comply with the various code requirements to obtain the RVIA serialized sticker you find on the side of RV's. While many will say they don't care about a darn sticker, it is a huge part of manufacturer liability insurance requirements, being able to sell a product that is code compliant, and to follow standards that they are expected to follow. You might not care, but they do.

Charles

[ehoepner]

My 2002 Casita 17 ft SD has soft cooper installed. I have intalled both black iron and soft cooper. Soft flared cooper is a whole lot easier to install than the black iron. Flaring is not hard, it's fairly easy to do. You do need hangers to attach the pipe to. That part of the installation is probably the hardest. Then making sure each fitting is tight and not leaking. Cooper is soft and very malleable and fun too work with.

[Eggcentric]

Originally Posted by Jakob R New York

Hi there!

I am converting a 8.5x20 Aluminum Car Hauler into a mobile dwelling and have some questions about running gas lines underneath the trailer for our propane system.

I have seen a lot of conflicting information regarding the type of piping to use in moveable dwellings as there is an obvious factor of movement which makes selection particularly important.

My understanding is that in most RV's, either iron or copper piping is used for the propane gas lines. I have read visceral reactions to using steel proflex (CSST) in moveable dwellings.

The proflex material looks very appealing in terms of simplicity. I'm curious why it is such a problem for moveable dwellings?

I was curious if someone with experience installing gas lines could inform me of the appropriate type of piping to use and the associated considerations:

1.) Rules for junction points (fittings etc). (Should you only use a single line from source to appliance? Or can you have a mainline that branches to each appliance?)

2.) Securing/fastening the piping to trailer frame. (Should there be some intentional movement allowed to prevent cracking over time?)

3.) Any advice about bending the piping (in the case of copper).

I like what I have read thus far about semi flexible copper piping however, I am a bit concerned that since all of the piping will be run underneath the car hauler (secured to the chassis/frame) that there is some level of risk for puncture/damage to the exposed piping itself.

Perhaps there is some sort of protective material that I could run the copper piping through to enhance its durability?

Any additional advice would be greatly appreciated if you have any other anecdotes not mentioned in the questions above concerning running new gas lines in a mobile dwelling.

I greatly appreciate all of your wisdom and kindness!

Cheers,
Jakob

Black iron in rubber lined steel clamps until the pipe is inside the trailer, then you can use copper.
Run a main with branches.
Thermal expansion is negligable make your floor holes 1/8th" oversize and seal them with urethane caulking. Do not let the copper touch any metal framing once inside the trailer.
You are only dealing with 2psi after the regulator so reasonable care will keep you safe. You also should put in a gas alarm so you and yours do not wake up to a surprize one day.

[rrobillard]

A few years ago I also converted a trailer designed for toy hauling to a travel trailer for a brother. I used 3/8” refrigeration copper coil for the entire project except going from the tanks to the bulk head fitting on the front of the trailer. I had no experience with flaring copper tubing so I watched some YouTube videos and practiced a little. I ran the main line on the inside along wall at floor so it was covered by cabinets. The only place I had to run under the trailer was from side to side to get from water heater/stovetop to furnace. I used bulk head fittings going through floor, ran the copper against a cross member, enclosed with 1/2” pipe insulation and used conduit clamps to screw to floor underneath. I then fabricated a rock shied out of .050 aluminum and covered the line. As far as using the flexible rubber lines to go from main line to appliances goes, I would advice against it on the interior of your build. All my research found it to be unsafe. Bending tool, flaring tool and tubing cutter are all you need. I tested each connection as I went along and then the entire system at the completion. The trailer has approximately 10,000 miles on it no issues. Below is a link to a short video of the finished trailer walk through if you’re interested.

Good luck with your project
Robert


https://youtu.be/tKZQ7eXgJDg