Galvanized air piping recommended over cooper

[ron in sc]

I finished installing my new compressor. It’s wired up and piped from tank to overhead supply line. At some point I’m going to change overhead supply line from ½" to 3/4". I used 3/4" copper to get from the tank to supply line with a 1' section of hose that’s 3/4" I.D. to handle any vibrations.

When I spoke with Compressor Services the distributor I purchased my compressor from their service department told me there first chose for piping is aluminum. There second chose being galvanized pipe because it lasts so long and it doesn’t leak. The third chose was copper; they told me it was not as good as the galvanized because it can breakdown a the joints depending on how much oil and water ends up going thru it.

I was a little surprised at this. After all my compressor does have copper line going from the compressor pump to the tank but it is connected with compression fittings. It does offer less internal resistance because it’s smooth inside compared to galvanized.

I think aluminum is kind of new for piping so I wonder how well it will hold up over time, say 15 or 20 years.

 

[HoosierBuddy]

Interesting.

Still, they are just expressing their opinion.

Aluminum, Copper, and Galvanized will all rust or oxidize to some extent. I've never worked with aluminum pipe. The only thing I can possibly see it would have going for it would be increased wall thickness over standard copper tubing, meaning it would take longer for any water to eat its way through the pipe wall...which is essentially what the galvanized is going to have going for it.

If it was a concern, you could use higher rated copper...but the real SOLUTION would be to use a really good filter/seperator assembly to keep the water out of the piping to begin with. Rust needs 3 things to occur...one of which is a "galvanic solution". Water (and any conductive oil) can serve as that solution. The more you keep out of your pipes, the longer they will last.

One of these days, some bright boy is going to come up with a really good plastic solution. Heck, I'm not that bright and I know how to do it. Someone needs to manufacture high density polyethylene or cross linked polyethylene (aka PEX) with a rigid steel outer layer. It couldn't rust from the inside, and the steel would keep the UV and stray beavers away from the soft PE tubing.

Now all I have to do is develop it, get it approved, and market it.

But I'm too lazy.

Phil

 

[bmwpower]

They recommend aluminum probably because they sell it (saw it on the home page).

And how will copper joints fail with water use? Does that mean my copper water pipes in my house are going to leak, too?

I'd probably rate copper as high as aluminum, depending on cost as I still have not received a pricing list from any of these aluminum vendors.

 

[wantedabiggergarage]

Interesting.

Still, they are just expressing their opinion.

Aluminum, Copper, and Galvanized will all rust or oxidize to some extent. I've never worked with aluminum pipe. The only thing I can possibly see it would have going for it would be increased wall thickness over standard copper tubing, meaning it would take longer for any water to eat its way through the pipe wall...which is essentially what the galvanized is going to have going for it.

If it was a concern, you could use higher rated copper...but the real SOLUTION would be to use a really good filter/seperator assembly to keep the water out of the piping to begin with. Rust needs 3 things to occur...one of which is a "galvanic solution". Water (and any conductive oil) can serve as that solution. The more you keep out of your pipes, the longer they will last.

One of these days, some bright boy is going to come up with a really good plastic solution. Heck, I'm not that bright and I know how to do it. Someone needs to manufacture high density polyethylene or cross linked polyethylene (aka PEX) with a rigid steel outer layer. It couldn't rust from the inside, and the steel would keep the UV and stray beavers away from the soft PE tubing.

Now all I have to do is develop it, get it approved, and market it.

But I'm too lazy.

Phil

Phil, do you mean like pex-al-pex that is already sold? As for a good plastic solution, there is (and it has been discussed before) an ABS pipe that is sold for airline use (rated as such, and colored differently to show that ).

 

[Aahz]

We have installed the TransAir aluminum piping in several facilities and like it alot. (Well, I like it....my pipefitters get pissed because it takes much less time to install...) I would highly recommend using it due to the ease of installation. The downside is the cost of the pipe and fittings...It isn't as cheap as black or galvanized...while I haven't compared the two side-by-side...it probably is in the high end copper range.

I've been thinking about adding the product to my website, but it's one of those things that will take some time...(and time seems to be in short) supply...

 

[HoosierBuddy]

Phil, do you mean like pex-al-pex that is already sold? As for a good plastic solution, there is (and it has been discussed before) an ABS pipe that is sold for airline use (rated as such, and colored differently to show that ).

Well...I was thinking of something rigid...but you are probably more on track with what will be developed. Seems like everything is going to coil based pipe, as it cuts installation time significantly. Mr. Pex (one brand of PEX-Al-PEX) retails for about $5 per foot for 1" pipe. That's going to make it pretty pricey compared to steel pipe. I bet it would work great, but I don't think it is approved by code for compressed air.

Just googling around, it looks like Duratec is a similar product made for compressed air, using standard high density polyethylene rather than PEX (cross linked PE). Duraplus is your ABS pipe.

I guess where I'm coming from is this; I buy A LOT of PE gas pipe. It's rated for up to 100 PSI in natural gas service and costs roughly 40 cents per foot in 1". It's completly unsuitable for aboveground service due to UV breakdown. If you armoured it with steel (which costs about 1/50th what aluminum does)...you'd have something cheap and durable.

Phil

 

[ZRX61]

They've been using plastic lined steel pipes for water in the UK for at least 30 years....

Edit:
Should point out I mean for the mains, not in houses....

 

[gerry]

Any threaded connection on pipe is a potiental leak. I cannot see how anything can be superior to copper tube with soldered joints. It goes up fast and easy to resolder in place if the need is ever there. Try doing that with threaded pipe. On the new fangled plastic systems, I just don't like the looks nor do I like the cost. I will use copper

 

[rustluver]

Any threaded connection on pipe is a potiental leak. I cannot see how anything can be superior to copper tube with soldered joints. It goes up fast and easy to resolder in place if the need is ever there. Try doing that with threaded pipe. On the new fangled plastic systems, I just don't like the looks nor do I like the cost. I will use copper

I agree 100%, Gerry. I'm using 3/4" Type L copper for the main run with 1/2" drops. There is no way I would fool with threaded pipe unless I was being paid by the hour to install it and leakproof it. I wouldn't have either aluminum or plastic air lines in my shop.

 

[Tscott]

I agree 100%, Gerry. I'm using 3/4" Type L copper for the main run with 1/2" drops. There is no way I would fool with threaded pipe unless I was being paid by the hour to install it and leakproof it. I wouldn't have either aluminum or plastic air lines in my shop.

I can see where you are coming from with the ease of install of copper. But that is if you are an experienced pipe fitter. When I was learning to do it on water pipes I can remember a number of pipes leaking when I was positive they would not, but with a little practice, it becomes quite easy.

As for the threaded connections being potential leak points, I have found this to be almost as rare as a leaking soldered joint on copper. I used to install black iron pipe in restaraunts for gas lines, and I could tell you if a pipe was going to leak or not. as long as the threads were done half way ok and you use a good glob of pipe dope, then you would be hard pressed to have a threaded connection leak. The only real problem i would have with BI pipe or Galv. for that matter is that you cannot cut and fit it yourself, but with a large number of standard ******* in different lengths available, I thnk you could probably make it work without any custom pipe.

As for corrosion, it's my experience that if the system is designed with a built in trap, that is the lowest point in the system, that can be drained regularly (Maybe once a month if you have a good dryer on your compressor). THen the chance of rust through is very small. I have seen 40 year old BI gas pipes that regularly get covered in water and the amount rust present is minimal. I have also seen BI pipe used for water and steam lines in food steamers. these lines endure tremendous pressures, and lots of water and I have never seen one pit or rust through. And most of these had RO filters whick made the water pretty reactive. I have seen an aluminum boiler pit through, but never BI pipe.

Not to say that I would go running the stuff in my house for water lines, but I think it's tougher than most people give it credit for. As for which I preffer, I would say that for ease of installl I would go with the aluminum, but I won't because it's to damn expensive. So my second choise would be either GS pipe or Copper. In my opinion they are equally as suited and I would let cost determine which I use.

Just my 2 cents
Tom

 

[Tscott]

I can see where you are coming from with the ease of install of copper. But that is if you are an experienced pipe fitter. When I was learning to do it on water pipes I can remember a number of pipes leaking when I was positive they would not, but with a little practice, it becomes quite easy.

As for the threaded connections being potential leak points, I have found this to be almost as rare as a leaking soldered joint on copper. I used to install black iron pipe in restaraunts for gas lines, and I could tell you if a pipe was going to leak or not. as long as the threads were done half way ok and you use a good glob of pipe dope, then you would be hard pressed to have a threaded connection leak. The only real problem i would have with BI pipe or Galv. for that matter is that you cannot cut and fit it yourself, but with a large number of standard ******* in different lengths available, I thnk you could probably make it work without any custom pipe.

As for corrosion, it's my experience that if the system is designed with a built in trap, that is the lowest point in the system, that can be drained regularly (Maybe once a month if you have a good dryer on your compressor). THen the chance of rust through is very small. I have seen 40 year old BI gas pipes that regularly get covered in water and the amount rust present is minimal. I have also seen BI pipe used for water and steam lines in food steamers. these lines endure tremendous pressures, and lots of water and I have never seen one pit or rust through. And most of these had RO filters whick made the water pretty reactive. I have seen an aluminum boiler pit through, but never BI pipe.

Not to say that I would go running the stuff in my house for water lines, but I think it's tougher than most people give it credit for. As for which I preffer, I would say that for ease of installl I would go with the aluminum, but I won't because it's to damn expensive. So my second choise would be either GS pipe or Copper. In my opinion they are equally as suited and I would let cost determine which I use.

Just my 2 cents
Tom

P.S. Just to show copper is not without its faults, I used to live in central florida and I distinctly remember my mother having to re-pipe a 10 yr old house because we were getting pin hole leaks in the copper piping in the walls. the Florida water was eating them from the inside out. So just goes to show there is no perfect solution, only the best solution for you.

 

[kbs2244]

This is a real case of go with what you know.
But, DO NOT GO WITH GALV.

The reason building codes do not want galv pipe in gas lines is they are afraid of flakes of the zinc coming off and clogging things up. If this can happen at the low flow rates and the 4 to 8 PSI of a gas line what will it be at the 80 to 120 PSI and flow of a compressor line doing sand blasting or painting?

Since you seem to know threaded pipe, I would go with 3 or 4 inch BLACK pipe as the main with 3/4 inch drops to each use piont. This will give you an above the ground storage tank.

DO NOT FORGET the so called drip points at each drop. Use a tee to come off to the air connector. And have about a 6 or 8 inch dead end below it. Look at your NG furnace or hot water heater for an example. These dead ends are a place for= all the **** flowing through the lines to collect.

 

[kbs2244]

By the way on the copper in FLA.
I just got back from a trip from a cono my family has in SW Fla.
I found 3 leaks in the copper plumbing.
The local plumbing contractor I worked with blamed it all on REVERSE OSMOSIS water treatment.
Something to do with more oxgen in the water and it atacking any imperfection in the copper pipe.
He said he does a conplete re-piping a week in our town because of this water treatment.
I remember when the city was selling this new way of treating water as the best thing since toliet paper. They didn't mention it would eat up your plumbing!
So, in this thread, do not worry about it in a compressed air line.

 

[RAYJAY]

ok I,m ready to get flamed... but I did a lot of research on air line piping

In my owners manual for my Ir compressor its states as a warning for discharge piping (DO NOT USE PLASTIC PIPE, RUBBER HOSE,or LEAD-TIN SOLDER JOINTS IN COMPRESSED AIR SYSTEM )

so i started looking at other boards on the web to see what every one else is doing ...........and that is BLACK PIPE and the pdf they all quote is form the tp tools web site link ,thinK about it....... Tp tools sells sand blasters if they can keep the air dry enuf for that then I'm going there install way

Jeff

 

[Charles (in GA)]

Indeed, they are correct, you should not use LEAD-TIN soldered joints. They do not have the strength margins for compressed air. No one uses lead-tin for soldering joints anymore either, due to drinking water contamination problems and low strength, (this is also known as Sn50 or 50-50). What is used is Tin-Antimony (also known as Sn5 or 95-5). On page 28 of the Copper Tube Handbook, published by the Copper Devolopment Association..................................

http://www.copper.org/resources/pub_list/pdf/copper_tube_handbook.pdf

............You find the strengths of the various type of soldered joints using different types of copper fittings (pressure and DWV non-pressure).

The strength of the joint is the reason you are told not to use lead-tin soldered joints. Up thru one inch, the working pressure of a lead-tin soldered joint at 150F (max) is only 150 psi, while a 95-5 soldered joint is 625 psi.

I have pointed out the strength issue with tin-lead in previous threads on copper pipe and that 95-5 (which is commonly used today for soldering water pipes) is the needed type of solder on copper pipe for air systems.

Here..... http://www.garagejournal.com/forum/showpost.php?p=50059&postcount=7

and here..... http://www.garagejournal.com/forum/showpost.php?p=38908&postcount=20

Charles

 

[toxicz28]

The third chose was copper; they told me it was not as good as the galvanized because it can breakdown a the joints depending on how much oil and water ends up going thru it.

I call BS!!!! My house is 40 years old, and the copper pipes have hundreds of gallons of water going through them everyday, no leaks.

 

[PAToyota]

Charles is right on the money and I'd be willing to bet that those with problems with copper air piping likely used "regular" soldier to do the joints.

 

[RAYJAY]

I call BS!!!! My house is 40 years old, and the copper pipes have hundreds of gallons of water going through them everyday, no leaks.

but remember the water you drink from your tap and the water in your compressor is 2 different things.

 

[Charles (in GA)]

but remember the water you drink from your tap and the water in your compressor is 2 different things.

Yes it is. The water in your tap is nearly netural Ph if you are on a public water system. They adjust the ph balance to prevent the lead from leaching out of older lead soldered joints in copper pipes. (Federal regulations require that public water systems test a sample of houses with led soldered pipes for lead in the water and adjust the ph to prevent the leaching).

If you are on well water, like I am, you are at the mercy of the water, unless you have equipment installed to adjust the ph, filters, etc.

The water in your compressor is esentially distilled water (neutral Ph), as it is vapor in the air, and then condenses in the tank and lines. It will have some oil with it, that comes from the pump (we know that isn't corrosive) and it will have some small amount of rust from the inside of the tank. Except for the oil, the water in your compressor's tank it probably more pure than the water out of your tap! Two stage compressors condense out virtually all water in the tank, due to the extreme heat rise and cooling, with little getting into the lines.

The issue with lead-tin (50-50) solder is quite simply one of strength.

I'll take copper over aluminum pipe anyday.

Not trying to argue, just that facts are facts.

Charles

 

[RAYJAY]

Yes it is. The water in your tap is nearly netural Ph if you are on a public water system. They adjust the ph balance to prevent the lead from leaching out of older lead soldered joints in copper pipes. (Federal regulations require that public water systems test a sample of houses with led soldered pipes for lead in the water and adjust the ph to prevent the leaching).

If you are on well water, like I am, you are at the mercy of the water, unless you have equipment installed to adjust the ph, filters, etc.

The water in your compressor is esentially distilled water (neutral Ph), as it is vapor in the air, and then condenses in the tank and lines. It will have some oil with it, that comes from the pump (we know that isn't corrosive) and it will have some small amount of rust from the inside of the tank. Except for the oil, the water in your compressor's tank it probably more pure than the water out of your tap! Two stage compressors condense out virtually all water in the tank, due to the extreme heat rise and cooling, with little getting into the lines.

The issue with lead-tin (50-50) solder is quite simply one of strength.

I'll take copper over aluminum pipe anyday.

Not trying to argue, just that facts are facts.

Charles

ok going to bite on this one ...... if the water in the tank is neutral ph then how does the tank from inside rust ? don't you need a acidic ph to form rust ??

jeff

 

[Junkman]

all you need for rust to form on iron is moisture. PH isn't a factor in rusting. Rust is oxidation caused by oxygen and moisture causing a chemical reaction on the iron. Ever see an apple rust? Oxygen and moisture causing a chemical reaction on the meat of the apple. Rust on copper? It turns green.. another form of oxidation. Many things oxidize.

 

[timgr]

ok going to bite on this one ...... if the water in the tank is neutral ph then how does the tank from inside rust ? don't you need a acidic ph to form rust ??

jeff

No I don't think so, but I had to look it up to be sure. This link agrees with me:

http://antoine.frostburg.edu/chem/senese/101/redox/faq/how-iron-rusts.shtml

If the water is acidic, the pH is low. The above site indicates that, if pH enters into the reaction, a low pH makes the formation of water in the reaction less likely, but is not required for the formation of iron oxide (rust). Acidic water is more corrosive, which I presume will facilitate rusting.