# Underground lines..Driving on them



## Buzz Saw (Feb 1, 2014)

Howdy,

I'm going  to be build a new garage/workshop that will also house my IWB.  

So my question is can you drive over buries water lines(I plan on using PEX) ?   The lines would sometimes have loads of upwards of 100k  lbs crossing them from time to time.  The grain semi's load is legal at 80K lbs, but if the corn is running wet you can easily go over weight.   I was thinking about installing concrete culverts or maybe pouring a "U" shaped footer to put the lines in and then putting a reinforced concrete lid on the "U" footer.  Just throwing out ideas.  The garage and house will be split by the driveway and there really isn't a better place to put the building on the lot due to the current layout of buildings, septic system and the pond.

Has/ Does anyone out there drive over their buried lines?  Have you had any problems?

If I can't drive on the lines I'll have to put the IWB in the house,which I really don't want to do, and I'll also have to find another form of heat for the garage.

Any help would be much appreciated.  Thank you


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## Dino57 (Feb 1, 2014)

Put them 5 feet deep and it should be alright


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## NE WOOD BURNER (Feb 1, 2014)

we use 1" steel plate on shallow utility for that purpose. spreads the load out a bit. ive seen thermo pex run inside the yellow gasline PVC? and that one sees a few heavy loads under the driveway.


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## 711mhw (Feb 1, 2014)

Yes on deep, for 2 reasons. Protection from the cold and everything else. Burry an egg 5' deep and you could drive on it.


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## Buzz Saw (Feb 1, 2014)

So should I bury them 5' and protect them with a  steel plate or just 5' and call it good?


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## heaterman (Feb 1, 2014)

This is how we did it for a situation similar to yours. The 2" pex lines went directly across the main drive into the farm and due to an old foundation and floor under the drive we couldn't get below 30" in depth.
So.....

We excavated as deep as we could get then set 2" of foam on the bottom of the trench. (18" wide) We laid the pex right on the foam and had the insulating company we use spray 3" on it. After that cured for an hour we took strips of the same 2" material. 12" wide and laid it up vertically along the sides of the trench like the sides of a box. We filled the inside of the box, and backfilled along the outside with sand at the same time until it was level with the top, then put a 2" "lid" on it and filled the trench the rest of the way with driveway gravel.

It has been in there for 5 years and there has been no settling or sign of heat transfer/loss at all.

PS........I should add that we compacted the sand as we backfilled so we had things pretty solid all the way up to surface.


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## Buzz Saw (Feb 1, 2014)

heaterman said:


> This is how we did it for a situation similar to yours. The 2" pex lines went directly across the main drive into the farm and due to an old foundation and floor under the drive we couldn't get below 30" in depth.
> So.....
> We excavated as deep as we could get then set 2" of foam on the bottom of the trench. (18" wide) We laid the pex right on the foam and had the insulating company we use spray 3" on it. After that cured for an hour we took strips of the same 2" material. 12" wide and laid it up vertically along the sides of the trench like the sides of a box. We filled the inside of the box, and backfilled along the outside with sand at the same time until it was level with the top, then put a 2" "lid" on it and filled the trench the rest of the way with driveway gravel.
> It has been in there for 5 years and there has been no settling or sign of heat transfer/loss at all.



That's what I wanted to hear.  I'm pretty sure I can get down deeper than 30".  Deeper the better I would imagine.


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## 711mhw (Feb 1, 2014)

I only speak from burrying other "utilities", not actually what you're doing. There is a "sticky" here I think that go's over the burried pipe & pipe/insulation issues. As far a being safe from crushing your pipe at 5', you'll be safe. When I burry anything that I think might need some service or attention, I'll run it in conduit of some sort of slieve so that it can be pulled. Very cheap insurance! Even if you have one of those dual pipe set up in what looks like 4" drain tile, it would not cost much to pull it through a 6" or bigger "drain tile" type sleive. I think that might also provide an air space that might help keeping your temps in the pipes.


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## Buzz Saw (Feb 1, 2014)

711mhw said:


> There is a "sticky" here I think that go's over the burried pipe & pipe/insulation issues




Read the sticky but didn't really go into detail about driving on the lines with heavy loads.  Maybe this should be added to the sticky somehow.  I'm sure I'm not the only person that drivers over the line withs 80k-100k lbs/




711mhw said:


> When I burry anything that I think might need some service or attention, I'll run it in conduit of some sort of slieve so that it can be pulled.



Agreed, but this will only work if I use the thermopex stuff.  I was thinking about spray foaming in the trench like they talk about in the sticky.  However it's something for me to consider, but I sure hope I never need to service my PEX lines.

711, How do you size your conduit for your electrical runs?  Do you base it off of number of conductors plus a few extra?  Does length of the conduit figure into the diameter of the conduit?

Thanks for your input.


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## Boil&Toil (Feb 1, 2014)

The lines themselves should be fine just buried deep. The insulation around them and the loads you are talking about make me think I'd go with the concrete outside the foam, though you might be able to simplify that quite a bit from what you describe, and may not need to [a chat with a soils engineer "on the clock" might save a good deal of expense in (over)doing the job.] If you do the quasi-standard foam box from the stickies here, and you were feeling a wee bit paranoid, a 3" concrete slab over the box would be all the insurance it should need, if the soil around the box is adequately compacted. Or you could move the slab up to driveway surface level - but pretty much anywhere between the pipe insulation box and the surface should work, if you feel the need at all. The slab adds another level of "load spreading" and reduces the pressure the pipe/insulation will see.

If concerned about seviceability, you can put in lift rings when you pour, and either pour in sections, or take a concrete saw to it in the unlikely event that you need to dig it up.

Supposedly standard blueboard is about twice as strong on a PSI basis as soil. Burying deeply reduces pressure levels as loads are spread into the soil.

As for conduit, put in at least two completely empty ones. Trenches are expensive - conduit is cheap. The only way length affects size of conduit is where it affects size of wire needed - for code purposes conduit fill is all about wire diameter .vs. conduit diameter. You don't want to be anywhere near code maximum fill if you'd like to have a reasonable day pulling wires.


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## Sodbuster (Feb 1, 2014)

Buzz Saw, I think it would be helpful to know how well the load on your grain semi is distributed, so you can get an idea of how many psi you are putting on the soil over your pipe. I had a guy doing some work for me with a 60,000 excavator, he told me due to the size of the tracks he actually put less psi to the ground than my pickup truck.


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## Fred61 (Feb 2, 2014)

Don't forget to run a length or two of para cord or poly rope in those service conduits when installing. Makes things easier later.

BTW Due to space limitations and geography on my property I need to drive over the output of my septic tank to access the space behind my garage. When I constructed the driveway I switched the pipe to sch. 40 pvc and surrounded it with masonry sand. It's only buried 3 to 3.5 feet and I regularly drive over it with my RV which weighs 35,000 pounds and I have had gravel deliveries weighing 70,000 pounds drive over it.


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## eauzonedan (Feb 2, 2014)

It's all in the backfilling and compaction to keep things from moving. In the days before PVC -they used vitrified clay for pipe(breakable stuff)  and it worked just fine under roads.  Start on virgin soil - or a compacted granular material if you overdug the trench.  Foamed in place would be my choice for pipe insulation if possible - other solutions may be needed if it is not available. Bed the top and sides with sand that is free of anything with sharp corners and then moisten it and compact with a plate compactor in lifts no more than 6" at a time. Go vertical about a foot and a half with the sand for every foot of trench width and you will be bulletproof for weight loading. FYI sand sucks for a cap layer as it's a bit like running in marbles - so add a strip of filter fabric or landscape cloth and finish off with road gravel on top to keep the sand isolated. 10-4 on sticking a few extra conduits in under the road. It's cheap insurance even if not used later.  Properly compacted the trench will not settle on you over time


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## 711mhw (Feb 3, 2014)

Buzz Saw said:


> Agreed, but this will only work if I use the thermopex stuff.  I was thinking about spray foaming in the trench like they talk about in the sticky.  However it's something for me to consider, but I sure hope I never need to service my PEX lines.


 
I wonder if anyone here knows how well the "thermoplex" type pipe performs within a larger tube/sleive with the combination of the air space around it and the smaller actual contact with the earth. I would think that this would help with heat loss quite a bit compared to a direct burry. The next question is how would this set up compare to the foamed in trench procedure.


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## Buzz Saw (Feb 3, 2014)

711mhw said:


> I wonder if anyone here knows how well the "thermoplex" type pipe performs within a larger tube/sleive with the combination of the air space around it and the smaller actual contact with the earth. I would think that this would help with heat loss quite a bit compared to a direct burry. The next question is how would this set up compare to the foamed in trench procedure.



This is why I'm so glad I found this site.  So many sharp minds coming up with innovative ideas to solve each unique scenario.   I wonder if the "Thermopex" method is cheaper if you figure in manpower.  With that being said I'm willing to spend money  to do it right, but I want to be as cost effective as possible. 


Sodbuster said:


> I think it would be helpful to know how well the load on your grain semi is distributed



I guess I never thought about it that way, makes sense though.

Luckily I have time before the project kicks off, but the more I learn now will pay 10 fold in the future.


Keep the good stuff coming guys!


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## NE WOOD BURNER (Feb 3, 2014)

I like the idea of using a highway load rated conduit for thermopex or logster type lines. Its piece of mind for me to think if ever there where a problem or a better product in the future one could simply pull out and replace.


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## Tennman (Feb 4, 2014)

Sorry Buzz, not a Civil engineer, but can give you crude numbers. Assuming 100k in the grain trailer = 50k on trailer axles and 50k on tractor axles. Assuming standard dual axle trailer or tractor 8 tires on either end of the trailer. Assuming 6"x10" tire contact = 104 psi per tire. I Googled soil compressive strength and Stiff soil comes in at ~60 psi, hard soil ~145 psi. The spray-in foam's good for about 90-100 psi. So it looks like you'd "probably" be ok at several feet deep because this assumes no load into the trench sides which will certainly happen. It's close enough I'd consult a no-kidding Civil P.E. or just bite the bullet and plan on a concrete pad over the lines. If it was me, I'd spend the money on concrete instead of the P.E and sleep well at nite because re-doing lines is no fun.


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## Buzz Saw (Feb 4, 2014)

Tennman said:


> Sorry Buzz, not a Civil engineer, but can give you crude numbers. Assuming 100k in the grain trailer = 50k on trailer axles and 50k on tractor axles. Assuming standard dual axle trailer or tractor 8 tires on either end of the trailer. Assuming 6"x10" tire contact = 104 psi per tire. I Googled soil compressive strength and Stiff soil comes in at ~60 psi, hard soil ~145 psi. The spray-in foam's good for about 90-100 psi. So it looks like you'd "probably" be ok at several feet deep because this assumes no load into the trench sides which will certainly happen. It's close enough I'd consult a no-kidding Civil P.E. or just bite the bullet and plan on a concrete pad over the lines. If it was me, I'd spend the money on concrete instead of the P.E and sleep well at nite because re-doing lines is no fun.



Agreed.  I've got a call into a college bud that's a  Civil Engineer  P.E.  He works for some big firm in Chicago.  He's going to run some numbers for me when gets a chance.  See what he comes up with, direct bury, concrete lid or conduit.  One this is for sure, I don't want to do it twice.




NE WOOD BURNER said:


> I like the idea of using a highway load rated conduit for thermopex or logster type lines.



Wood burner, do you think Thermopex or logster will keep my temps from dropping as well as direct foam?  I've read multiple threads with people giving good results both ways, but with the thermopex the lines are so close together is the hot line heating the cold line instead of heating the house?  I guess that's my biggest concern , and well of coarse my best bang for the buck.


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## NE WOOD BURNER (Feb 4, 2014)

Buzz Saw said:


> Wood burner, do you think Thermopex or logster will keep my temps from dropping as well as direct foam?  I've read multiple threads with people giving good results both ways, but with the thermopex the lines are so close together is the hot line heating the cold line instead of heating the house?  I guess that's my biggest concern , and well of coarse my best bang for the buck.


I have seen the thermopex  in a 8" gas line conduit run about 150' all plowed no snow cover and an additional 75' run its hooked to a CB classic and a FHA HX in two locations. They have been working great. no temp sensors to check temp drop though. I have not used urecon Logster pipe but they have lots of products two line or single line(larger ID opening)(some have wires). I learned of that brand off this site so others could add more on that. could you do better(rvalue) with foam in place probably. takes more time though. the conduits and small diameter culverts will have highway load ratings and install directions from the manufacturer. I just like the idea of being able to service utilities after the install or to remove pipe and bring with me if situations change. We run cranes, excavators,loaded trailers over the steel plates for temp access over shallow utilities all day long. If you can find used piping and reuse save some dough. the gas line conduit was a street tear up and repurposed. depending on length of run its quicker to dig place and backfill. then pull the pipe( we used rope run at time of conduit placement). for me its economics with equipment I rent or hire for my independent projects so hours are dollars. if you are installing in a busy spot then foam contractor may tie you up on schedule. foam in place has advantages but time to install Im not sure is one of them. depends on your situation though.


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## Boil&Toil (Feb 4, 2014)

Buzz Saw said:


> with the thermopex the lines are so close together is the hot line heating the cold line instead of heating the house? I guess that's my biggest concern , and well of coarse my best bang for the buck.



This is precisely my concern (as well as the ungodly price) with this stuff. Making a very long underground heat exchanger...the blueboard+sprayfoam with blueboard separating the lines looks a lot better to my gut feeling, and costs either less or no more, usually.


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## NE WOOD BURNER (Feb 4, 2014)

have your engineer look at your real weight of trucks you will be running in a maneuvering position also. backing and turning etc. bridge formula gives you only the drive over weight mind you at highway speeds.


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## Buzz Saw (Feb 4, 2014)

I totally agree with Wood Burner when it comes to time, money and serviceability, On the other hand i also agree with Boil&Toil with better(perceived) insulation values. I feel like I'm  a dog chasing his tail.Oh what to do.......

All have valid points, luckily(and unlucky) this project won't happen for another year or so.  I guess I'll see what sort of supplies I can scrounge up to help make the decision.


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## NE WOOD BURNER (Feb 4, 2014)

How long of a run are you planning?


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## Buzz Saw (Feb 4, 2014)

barn to house will be in the neighborhood or 100' plus line in the house and bar.   I've yet to build the barn so the distance is subject to change


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## NE WOOD BURNER (Feb 4, 2014)

1400 for direct bury pipe and a day of machine and operator. not bad. check with urecon and thermopex they may have specs for the loads you are carrying. the real installers on this site have done it already im sure. Heaterman always talks of his old farmer friend


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## Tennman (Feb 5, 2014)

Buzz, Be great to share what your CE comes up with in the underground sticky. This question comes up fairly often and usually the answer is based on a successful experience from the kind pros who help folks out here for free. Most likely your friend has some type of table to tell him compressive psi as a function of depth. 

As I recall all the pre-foamed underground products use the polyurethane so the insulation properties are the same as the in trench approach. That makes foam thickness essentially the only factor in which process provides the best insulation. My barn to house underground run is ~140-150' (add maybe another 50-60' in root cellar and boiler barn). If our underground run had been 30-50' probably would have gone with Thermopex or Logstor. During long periods of idling with the pump running (only energy loss is line leakage) I've seen less than a 3 degF (actually ~2 deg) temp loss for the ~350' round trip including through the water to air HX. No question which method is the most thermal efficient, but having the plastic protector adds some value. For really long runs like ours the extra foam thickness translates into less wood usage not sure how much. But I CAN tell you first hand about the energy loss from a bad underground! Looking forward to hearing what you learn from your CE buddy. Best wishes, take your time. Gotta go make money.


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## NE WOOD BURNER (Feb 5, 2014)

so sdr 35 conservative numbers is about 5% deflection @ 4' burial depth. @ 80,000 pounds load so you lose 1/4" I.D. soil type is critical to this deflection(adjust accordingly). so a 6" pipe will be 5 3/4"  an 8" pipe will be 7 1/2". so this deflection would be on the conduit pipe not on the premade insulted pex.

150'/10' = 15 lengths     15lengths x $30(6" sdr 35)= $450

150'x $14per ft= $2100

so total materials $2550
budget $2000 for  excavator and operator you are at $4550 for 150 feet or $33.33 per foot installed
add if backfill material is needed

FYI:http://jmeagle.com/pdfs/PVC_Products_Brochure.pdf


Maybe some one can share foam in place $/ft cost for comparison


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