PEX as diesel fuel line

[Tom Reed]

I've been given a 200gal heating oil tank and am planning to locate it about 75' from the generator shed. The plan is to use a transfer pump to fill the day tank from the big tank. Since I have it, I'm thinking of using 1/2" pex-al-pex buried from the tank to the engine shed. Anyone have any comments on using PEX with Diesel, K1 and WVO? I'll use black iron pipe for the risers and copper for the flexible connections.

[BruceM]

Tom, I have been using Pex for my fuel transfer system for the last 7 years or so.  No changes of any kind to the pex.  I did run the same tubing for a few years on biodiesel, and that didn't seem to affect it at all either.

I  use 1/2" Pex for a flexible whip end for sticking into my 5 gallon fuel cans, which is then pumped up to my gravity tank.  I really like that as it's easy to wipe down, and the tapered (uncut) end from a small tube of silicone caulk fits into it as a seal.   It has enough flex to do what I need and it stays coiled and capped till the next use.

I wasn't initially sure how it would work out over time, but now I would recommend it without reservations.

[mike90045]

I'd never thought of PEX

PEX = crosslinked  polyethylene

https://plasticpipe.org/pdf/tr-19_thermoplastic_pipe_for_transport_of_chemical.pdf   shows
Gasoline, JP-4, JP-5, Lubricating Oil (ASTM #1,2,3)  to 73°F
Isopropyl Alcohol, Kerosene to 140°F     no diesel in their chart

So for intermittent use, away from any UV light, it looks interesting.   I need to make up some siphon tubing for transferring fuel, vinyl kinks too easily, maybe PEX will be better.

[Tom Reed]

Mike, If you want some let me know, there is a bunch of 1/2" left over from the hydronic floors.

Now on the risers, Al or Cu?

[LowGear]

As Mike wrote: "away from any UV light".  PEX has no tolerance for Sun light.

Casey

[BruceM]

Good point, Casey.  My PEX is inside my engine shed.

I use foil tape as a UV protector for exposed rubber, plastic, etc. here as the UV at 5600 feet elevation is brutal.  Plastics fail in the sun MUCH faster than at sea level.

[Tom Reed]

That's why the plan is to use aluminum tube for risers. In my experience clear pex will crumble quickly if left in the sun. The colored blue or red I've outside for years with no problems. What is going to by used for fuel line is hepex which has an aluminum barrier.

[mike90045]

I think copper weathers better then mill aluminum.     When you call risers, are they just protective shield for the tubing, or will they flow diesel in the pipe ?

[LowGear]

As a aluminum sticky tape fan I have to ask.  Is the hepex compatible with the shark bite fittings?

Casey

[Tom Reed]

Mike, Yes on the fuel flow. In the previous installation 3/8" copper pipe was used inside of 1/2" poly pipe. The plan is to swage a fitting to the pex under ground and have copper or aluminum "riser" up to the tank and gen shed.

Casey, Yes on the sharkbite fittings.

Retrieved the tank successfully on Saturday. It was in a fairly inaccessible spot behind the garage under the redwoods with a rather narrow path back to the tank. I started by using my transfer pump to fill a 55 gal poly drum, but this left 10" of fuel still in the tank (around 40 gal). So what we ended up doing was using a cherry picker on the tank slab to lift the tank and maneuvered my 4x8 trailer by hand behind the garage and under the tank. What a project.