Below Grade PVC Conduit & PE Gas Pipe Install Question

[StreetThisEVO]

I recently dug a trench (25" deep x 12" wide x 25' long w/ (1) 90 degree bend) and am getting ready to cut some holes in my foundation. The plan is to bring new electric, gas, and low voltage from my home to my external garage. My original thread showing the trench can be seen here: http://www.garagejournal.com/forum/showthread.php?t=266771&highlight=streetthisevo

For esthetic purposes I really want the lines entering my home to be below grade so they are not visible. Everything going to my garage will enter above grade through risers then through the siding, etc...

Gas (natural gas) will be buried @ 24" below grade using yellow PE gas pipe with GasTite brand con-stab fittings/adapters. I have a GasTite 90 degree riser for the garage side as well as their transition piece for the section that enters the home below grade. A tracer wire will be ran along side the PE pipe. No PE pipe will enter the home or garage. Black steel pipe will be used from the source to the start of the PE pipe and then from the riser into my garage.

My electric and low voltage will be run in separate 1-1/2" electricians PVC conduit @ 18" below grade. So two separate conduit runs side by side. Again risers will be used as these two lines enter the garage.

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Now.....my main questions.

1. If I bring everything I mentioned into my home below-grade through my concrete block foundation what is suggested to help seal everything up?

2. The GasTite brand transition piece that enters the home below grade is basically half PE and half steel. I am going to sleeve the block with a section of the same PVC 1-1/2" conduit I'm using for my electric. What is suggested to seal the gap between the transition piece and the ID of PVC sleeve?

I'm thinking of using an expanding water/fire resistant foam for the voids in the block after drilling my holes. Then once the PVC conduit is in place use hydraulic water stop cement to seal it to the foundation. Then maybe a silicone or solvent based water proofer over the cement once dried. I'm not 100% sure what would be best to fill the void in the sleeve though. Maybe expanding foam then silicone on either end...??

Any help would greatly be appreciated!

 

[sands35]

Check your codes and with your inspector. Gas may need to come in above grade for safety reasons. Gas leaks on the line won't leak into your house that way.

I'd also think hard about the electrical coming in below grade. But for water leak issues that can show up.

I'd rather build a small "dog house" or put a shrub over the risers than deal with water leaks or the risk of a gas infiltration problem. The risers really aren't that big, maybe 1 foot over grade and they stick out 3-4 inches.

My AHJ was OK running 2 conduits and 1 gas-line in the same trench. They did want the gas-line below 24" and the electrical below 18" - so ~6" of dirt between them.

 

[StreetThisEVO]

Check your codes and with your inspector. Gas may need to come in above grade for safety reasons. Gas leaks on the line won't leak into your house that way.

I'd also think hard about the electrical coming in below grade. But for water leak issues that can show up.

I'd rather build a small "dog house" or put a shrub over the risers than deal with water leaks or the risk of a gas infiltration problem. The risers really aren't that big, maybe 1 foot over grade and they stick out 3-4 inches.

My AHJ was OK running 2 conduits and 1 gas-line in the same trench. They did want the gas-line below 24" and the electrical below 18" - so ~6" of dirt between them.

Thank you for the response. I've put a lot of thought into this and do agree that coming into the house above grade probably makes the most sense. It just delays my progress a few more days as I wait for the part I need to be ordered. I think it is going to snow here in Ohio tomorrow. 'sigh'

Since my trench is roughly 12" wide the gas line will be placed on the opposite side of the trench as the electrical. This gives them 6" of vertical separation and roughly 10" of horizontal separation.

 

[sands35]

Yeah - SW MI here - a bit of snow during lunch today.

Check with your AHJ on the conduit in trench. Logically shouldn't be a problem, but it will save you hassle later if the answer is different.