Soft copper propane lines

[Mark W, Elite 32]

BAYC recommendations lead me to believe that continuous runs from the propane tank (solenoid/regulator) to the appliance (HW heater and stove are prefferable. I would prefer to run 3/8 soft copper as I have now but with the split at the regulator, not tapped into the line as it passes through the head.

I can make continuous runs, the flared fittings etc, but my question is with the materials - My usual suppliers (WM and Defender) only supply flexible hose, not soft copper. However I can obtain soft copper from Lowes, HD or online at Cornerhardware.com. Is there any difference between this and marine propane soft copper pipe ?

Thx

[Dave,397]

I cannot answer this from a boatbuilding perspective, but I can speak to it from the perspective of one who spent 7 years wiring and plumbing sports racing cars.

Soft copper tubing is not allowed for the transmission of any potentially hazardous substance by most, if not all sanctioning bodies for one very good reason:
Copper tubing, exposed to vibration and/or rattling, will eventually work harden and crack unless it is very well supported. While I have indeed seen copper tube last a very long time on old boats, tractors, and refrigeration gear, I have also seen how vulnerable it indeed is to fatigue and cracking. This is probably why all the marine outlets only sell hose for the propane systems, I'm guessing. BTW, I have also seen copper tube used in propane plumbing in motor homes. Also seen a bilge explosion once...and once is enough.

Hose, properly installed and protected from chafe, is in my mind a much safer option if well and properly installed and periodically inspected...it is also unlikely to corrode, especially if connected to stainless steel.

Like I said, not a "boat" opinion...but I wouldn't do it on my boat.

best,
Dave

[Tim]

"Soft copper" tubing actually means the copper has been annealed by heating it to soften it, which changes the molecular structure somehow. Annealed copper tubing is acceptable for use in an LPG system as long as the tubinc is Grade K or L, and conforms to ASTM B-88-75a. They guys at the store may look at you oddly if you ask for this information, but you should be able to get it. Or, look for an industrial plumbing and heating supplier.

Note that if you have a gimballed stove, you should install a length of flexible hose at the appliance to allow for the proper swing without damaging the copper. This means you end up with one more connection in the line.

If you do use copper, proper supporting is important, as Dave said. Installed correctly, it provides an excellent installation. I think you don't find this tubing readily available because its installation is beyond the realm of many DIYers, and the pre-manufactured hoses are approved, safe, and easy to install for most. There's almost certainly a liability issue at play here for the retailers too...

LPG is a great fuel, but all care and precautions should be taken in its installation and maintenance of the system. Well installed and maintained LPG systems will not cause any trouble. Cut a corner, and you're on your own.

I can provide the full text of ABYC A-1 (the section covering LPG installations) to anyone who is interested in the "real" recommendations, to reduce confusion and misinformation. I believe that these recommendations, while technically voluntary, should be followed closely in order to ensure safe installation. If you're interested in a copy, email me outside of the forum and we'll discuss delivery methods.

[Mark W, Elite32]

Thanks Tim, I managed to get a copy of the recommendations and am going with the cut to length flexible pipes (runbber, poly ?).

I have everything ready to go :

Tank to Regulator via hose provided.

Regulator to Solenoid via 3/8 Male NPT to 3/8 Male NPT adaptor

Solenoid to T, with 2x 3/3 Flares'

2 hoses through watertight connections -

1 to water heater, 3/8 femal flare works fine

2 to the original ENO stove and this is where I ahve a problem. The ENO stove is European and the union is not 3/8 NPT, its pretty close but no-one can identify the thread. The stove has a male flare on it and I do have the old femal barb to flare fitting that fits fine, but I cannot adapt it to fit the 3/8 female flare on the hose. As a last resort I am considering cutting the hose and attaching the existing fitting with double clamps, against ABYC recommendations.

Any idea what the thread could be and where I might get a union to adapt and connect ?

None of my local places seem to be able to help, I'm off down to Newport tomorrow with parts to see how I do down there, they must get a lot of foreign boats stopping in for repairs

[Noah]

I'm trying to sort out the propane system for the Swede and a search found this thread.

Strangely enough I also have an Eno stove, which looks like it was connected with a cut piece of hose and two hose clamps because of the strange thread on the Eno. Anybody have a suggestion to fix this?

Also, what was the decision on Rubber propane hose rather than copper? There is copper in the boat now, but I wonder how old and in what condition it's in. I would rather purchase a pre-made length of rubber hose and use that.

Like this:
http://www.defender.com/product.jsp?pat ... &id=127027

What do folks think?

[Tim]

Premade rubber LPG hose is a good choice. Just remember that you cannot have any fittings (Tees, etc.) between the solenoid and the appliance; if you have multiple appliances to run, such as a heater, stove, BBQ, etc, you must home run each supply line.