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morpho 08-02-2011 12:41 PM

DIY insulated septic pipe
Okay here goes:

I have a septic pipe that will be run approx. 18" underground for about 35'
And it gets cold here....really cold. Like -40 cold.
Heat tape can't be used because we simply do not have that much power.
There is no option to run it below the frost line. (about 4-5 feet or more, but it doesn't matter as this is not an option)

I was thinking about two options:

1. Centre the 4" pipe inside a larger pipe and fill the void with insulation...spray foam...I don't know...throw me some ideas.

2. Run a length of flexible tubing along or wrapped around the pipes length and back again to the house so I can create a loop to run hot water through to defrost the pipe.

Or maybe a combination of the two.

Any thoughts? ideas? (besides moving to a less god forsaken part of the world)


Lightfoot 08-02-2011 04:20 PM

My friend, i cannot even begin to imagine what -40 would feel like!
I don't know what to tell you but both of your ideas seem pretty good to me:thumbsup: Although circulating hot water i would think that would get expensive. Maybe a geothermal type unit, but if it gets 40 below there, you probably couldn't get it deep enough.

Adam_M 08-02-2011 10:29 PM

My first choice would be ask around about different heat trace products that coupled with maybe fiberglass insulation and double that up.

Or redo your septic field so it's not so far out.

morpho 08-02-2011 10:37 PM

hmmmm? do you explain -40 to someone who has never experienced it? I have friends from tropical places and have spent many a night on palm covered beaches trying to get this concept across to them. I have failed every time.

I was playing with a 4" and a 8" and was having hard time figuring out how I would get the abs to stay perfectly straight inside the larger pipe.
Start pumping in spray foam and who knows what the shape of the pipe would take!
I could end up with a bow in the line and would lose the angle I need.

So now the heated water pipe is looking good.
Yes it would cost a bit if I was running it all the time...but I would only turn it on if I suspected it was freezing up.

Geothermal would be works in the area, but costs a lot and needs a lot of power. I'm living off the grid so we have to keep things as power frugal as possible.

morpho 08-02-2011 10:43 PM

Hi adam,
I simply don't have enough power for a heat trace system.
doing any kind of Electrical heat would leave me in the dark so fast that my wife would kill me.

Moving the holding tank is not an option either...Oh if it were only that simple!:no:

Adam_M 08-02-2011 10:43 PM

I lived in northern BC for 20 years I understand the cold, here is a link to one product as an idea

If you want to spray foam, the one method I have done in the past for furnace ducts was dig your trench wrap it in poly put your pipe in on blocks then foam around it before finish wrappin the poly.

md2lgyk 08-03-2011 11:27 AM

I guess I'm not understanding your concern. Sewer lines are empty almost all the time.

morpho 08-03-2011 12:31 PM

Hi md2lgyk,
Yup, you are right...but I would be worried about a slow build up of ice, and once its frozen - it's frozen - and winter is LONG here.
(The snow started in Oct. finally melted in the middle of May this year.)

It may not be a may all just flow slick as...well you know.
But I would like someway to mitigate any problems before they have the Mrs. pooping in a bucket. Because if she has to do that...well, my life gets pretty miserable!

Okay, must get back to digging.


GottaFixIt 08-03-2011 01:32 PM

Can't you just flush the line with hot water or a salt water solution if it begins to freeze up? Maybe put a Tee with a clean out in right before it exits the foundation?

rjniles 08-03-2011 01:49 PM

My experience is that a septic tank as long as it is used normally will generate enough heat by bacterial action to keep things from freezing. The heat backs up into the inflow pipe to keep that unfrozen.

shazapple 08-03-2011 02:06 PM
(skip to the pictures)

Dig it up, put 4" styrofoam board on the sides and top (with lots of overlap) and bury it again.

morpho 08-03-2011 04:00 PM

Lots of thoughts about my pipe.

I have a couple of clean outs planned for the line.

Hopefully bacterial heat will keep the end of the pipe free and clear, but I wouldn't count on it keeping all 35' free and clear.

The hot water down the drain might work if done on a regular basis in large enough volumes. (this is a situation of homesteading....we don't have an endless supply of water. I know what you are thinking...a few gallons of water...whats the big deal? Well, we have to use less than 3 gallons a day so we don't run out before winter breaks.) We use in a year what most people use in a week so I cringe at the idea of "wasting water".

The PDF is interesting...makes me even more concerned in the end actually. The depths shown are all about 6' deep! I am limited to 18 inches of depth.
But I do think the idea would help as long as there was no standing water in the waste pipe.

Thanks everyone.

biggles 08-03-2011 05:39 PM

unless there is a constant flow of water even cold couple of hot showers in the morning bathroom use will keep the line free of ice.for water to change to ice the heat in the water flowing down would have to drop to fast below 32F to even start to frost or crystalize within the pipe plus the bacteria within the pool produces heat when it is breaking dow and that rises up the pipe to heat it..sure its not 75F but it certainly is above freezing which is 32F..........water at 32F taken to 32F ice takes a super blast of heat loss and without constant flow the line will never block up with a hot shower or dinner dishes being done daily.consider making ice cubes how long does it take your freezer to make that change:whistling2:

morpho 08-03-2011 07:29 PM

I don't know how long it takes to make ice cubes...I don't have a freezer! :laughing:

The general consensus is that I should have nothing to worry about.

I don't know if that should make me feel better or severely concerned!

I suppose the positive part is that if I do need to dig it up it's only 18" not 6 feet.

What to do what to do?

I think I will run a loop of flexible poly and that way I have the option if somewhere down the line it goes sideways.

Any other thoughts?

Javiles 02-02-2013 08:07 PM


Originally Posted by saltracer (Post 1108202)
Removed spam link

The guy that started this post moved to Hawaii last year.. :boat:

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