Burying a Brass and Copper Union

[ron in sc]

I need to use a union on my compressed air system which I'm running outside and underground for the new garage. A photo of union is below.

Just wanted to make sure it's ok to use bury these things. I assume it's ok so long as the threads are kept clean when the union is screwed together.

 

[bmwpower]

I need to use a union on my compressed air system which I'm running outside and underground for the new garage. A photo of union is below.

Just wanted to make sure it's ok to use bury these things. I assume it's ok so long as the threads are kept clean when the union is screwed together.

I'd prefer to see a soldered joint underground. Is there anyway you can put the union above grade?

 

[trovato]

My propane line has a union in it underground. Propane company installed it that way. Good enough for propane, good enough for air I guess.

 

[ron in sc]

Is there anyway you can put the union above grade?

No, not as far as I can determine.

I'm making a drain leg with a ball valve on the bottom at the lowest place the 3/4" pipe will be located where I am running air pipe to my garage to be. See drawing below.

What is circled I want to be able to remove if need be to service or change the ball valve on the bottom. The pipe enters the PVC pipe thru holes I've drilled.

 

[bmwpower]

No, not as far as I can determine.

I'm making a drain leg with a ball valve on the bottom at the lowest place the 3/4" pipe will be located where I am running air pipe to my garage to be. See drawing below.

What is circled I want to be able to remove if need be to service or change the ball valve on the bottom. The pipe enters the PVC pipe thru holes I've drilled.

That's an ingenious idea. So what is the depth of the drain leg? So the union is not in dirt, but in an air space?

 

[Junkman]

My propane line has a union in it underground. Propane company installed it that way. Good enough for propane, good enough for air I guess.

I am not familiar with the local codes in NY, however, in MA & CT, the propane companies will not install anything but a one piece of special plastic line that is specific for propane in the ground, without any breaks in it. They also require a special fitting for where it enters the ground, and where it exits. Just because some installer did it with a union, doesn't make it right. I suggest that you ask the propane corporate office to be sure that it is proper. If air leaks, there is no problem. If propane leaks, then it can result in a big problem. Underground gas and electric are both governed by strict codes in most of the US.

 

[ron in sc]

So what is the depth of the drain leg? So the union is not in dirt, but in an air space?

The width of the pipe is only 6" so it looks like the unions will have to go on the outside of the pipe. There's just not that much room on the inside even using a brass tee that has female threads. The length of the 6" pipe is 32" long with the holes thru which the copper pipe will pass being 16" from the top of the pipe.

Fitted to the top of the pipe is a bushing and then a cleanout plug to seal it up. I think the PVC pipe would have to be 8" or 10" wide to accomdate all the fittings inside; so with my system it looks like the unions will go on the outside of the PVC.

As far as the depth of drain leg goes I've not made it yet. It will be deep and a pain to flip the vavle open and closed. I have, however, thought of a way to make a fitting to attach to the ball vave so it can be opened and closed from the top with a rod that attaches to the valve.

 

[1320stang]

Well, why not wrap the union with an oiled cloth, then duct tape around it all and bury it.

 

[trovato]

I am not familiar with the local codes in NY, however, in MA & CT, the propane companies will not install anything but a one piece of special plastic line that is specific for propane in the ground, without any breaks in it. They also require a special fitting for where it enters the ground, and where it exits. Just because some installer did it with a union, doesn't make it right. I suggest that you ask the propane corporate office to be sure that it is proper. If air leaks, there is no problem. If propane leaks, then it can result in a big problem. Underground gas and electric are both governed by strict codes in most of the US.

It's common practice around here. At least it was when my lines were installed. And apparently, it still meets code. Check out:

http://www.copper.org/applications/fuelgas/rg-intro.html

 

[Ryan Wilke]

Ron,

Instead of using 6" PVC pipe, why not use a section of 8 or 10" painted metal stove pipe? If you backfill around it with a 4-8" of clean sand (clay soil would 'eat on it' over time), I'd bet it would last you plenty long enough and it may give you the room to contain all the fittings and be less expensive. Use a galvanized cap to cover it and place a bird bath, flag pole, large-ish field stone as a marker so you don't loose it's location in the yard.

I'd also ensure that I place at least 10" of washed gravel UNDER the ball valve and drip leg to allow any ground water to drain away from the fittings and any condensate that you blow out annually. You are planning to crack the valve and blow out the drip leg periodically, correct?

I like your idea of being able to open the valve with a rod attachment. If you attach a pipe clamp at each side of the valve to a piece of treated 2x8x ~14" long, this will secure the valve preventing it from twisting when you turn the rod.

Will you also have a valve & drip leg at each end of the line (near the point of going underground) just to keep the the amount of condensation to a minimum that heads down the 'cross-country' line?

How many feet of pipe will be buried?
If it's over ~75', you may want to step up to 1" pipe to keep the volume up and reduce the restriction of the long stretch of pipe......

Good Luck!
RWilke

Edit: Here's a good table to reference regarding the length of pipe run between your garages and the volume of air you'll want at the far end:
http://www.airheads.net/tech/techinfo/airline.html
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[ron in sc]

RWilke,

You are planning to crack the valve and blow out the drip leg periodically, correct?

Yes it is very easy to access, so I could open it daily if need be.

Will you also have a valve & drip leg at each end of the line (near the point of going underground) just to keep the the amount of condensation to a minimum that heads down the 'cross-country' line?

Yes there will be other drip legs too. But the one underground is quite deep. For instance the depth of the hole is 42" with a little gravel in the botom of the hole. Suffice to say that any water in those lines will drain into the little tank I made.

I have started a new thread with photos of tank and with it installed.

 

[74NovaSS]

Just another option to consider....using a sprinkler valve box such as any on this page. Then, you won't have to bury the unions. You might be able to fit the whole setup in there.

Chris