Air resovoir tank...PVC?

[Mark Jerde]

Aye. The scars on my left hand after a July 2003 (IIRC) TS kickback accident are still clearly visible.

-- Mark

[John Sellers]

Dave, how can you continue to denigrate people - not to mention the manner in which you do it - for whatever you've read in their remarks; and then get so "that way" yourself when others do the same with replies to your posts?

Everybody has the right to express their opinion, but most people here agree to disagree in a civil manner. And you really are a part of the discussions here. Wouldn't you like to be regarded with an improved temperment by the group?

Please chill with the 'bad' behavior. You'll be better for it.

John Sellers

[Bay Area Dave]

go back and re-read his previous post, John. His attitude was totally uncalled for. We have a long running feud. I hadn't posted anything that drew his smart-assed comments. So I called him on it. And if he does it again, I'll call him on it again.

dave

John Sellers wrote:

[John Sellers]

Not the point, dave. I didn't see anyone feuding with you. Neither did I see any comments aimed at you. But your response - which IS aimed, by the way - is degrading and maligning.

If Greg wants to believe what he said in this thread (or any other), that may be a detriment to his health; but weighed against advice in other posts, his opinion will be judged by all. Many will disagree, and several will challenge. But you're usually the one who jumps in with the childish slams. And you never seem to have the capacity for any disagreement with your own viewpoint/opinion.

It doesn't make for civilized discourse when the group reads responses like you made.

Go back and read what YOU wrote. THAT'S why you catch so much shit. From everybody.

Wise up. John Sellers

remarks;

improved

[ToolMiser]

I used to work at a place that had a 20 hp compressor and we piped the air with

2" PVC. Well after about 5 years we had some repairs done to the compressor, and the mechanic warned us about the dangers of PVC, especially "old" stuff. Within a few months, we started having trouble with a bunch of the joints coming loose, and we repiped with copper. After seeing this, I would never chance using it.

[Greg]

We do? Damn I missed it.

I only suggested this would be a good thing for mythbusters to try. They do prove about half the "myths" are true. Have you ever watched the show? If this is really what everyone says it is they could show us high speed photos of the explosions and their test dummy getting whacked again. They also use a lot of ballistic gelatin that shows the damage projectiles inflict on soft tissue. I never said this wasn't a real danger, only the results of one unscientific test which I referred to as anecdotal.

[Edwin Pawlowski]

Lighten up? Get the facts.

I work with pressure vessels. I'm licensed to operate high pressure boilers. My shop has an assortment of air receivers, boilers, vacuum tanks, deaerator tanks, steam accumulators, etc. Every pressure vessel must comply with certain specifications, fabricated by certified shops using certified welders, must be state inspected, some licensed, all periodically inspected. Every one is equipped with pressure relief valves (that also must be tested periodically).

Come to my shop and I'll let one of the relief valves go. After you change your underwear, see if you can tell me that a PVC tank is OK for air. I can assure you the mythbuster guys would not accept such a challenge as they are much too smart that to take a risk like that. Ed [e-mail]

[Greg]

Ed What happens when an internally rusted out steel tank ruptures?

When was the last time ANY of you had a VIP on your tank?

[Doug Winterburn]

The only one I've seen that rusted out got a few pinholes and wouldn't hold pressure - so it went to the landfill rather than exploding. Of course, that's only one...

-Doug

[Greg O]

Tell that to my boss. One inch higher and he would have been missing and eye from flying PVC shrapnel. Greg

[Edwin Pawlowski]

That is one benefit of steel. It may rust, but it will develop a leak, a thin section, usually the size of a dime, may blow through, but unlike plastic, it will not explode under normal conditions. Rubber air lines are the same way. they may split, but you don't get the flying shards. Metal can also be inspected so there is some predictability that a tank may soon fail. Inspection will reveal this both visually and even a simple tap on the tank with a hammer will give a clue. Plastic is catastrophic, usually showing no signs of impending failure.

High pressure steam is another story. The vessel can blow with force (I've seen a brick wall taken out when the end of a boiler blew off) but the metal itself it not nearly the problem of the hot vapor that is rapidly expanding. Ed [e-mail]

[Dustmaker]

Did you ever hear of the Darwin awards? They are given posthumously to those who demonstrate the most unique ways to prove the theory of survival of the fittest.

[Herman Family]

This particular setup probably won't get the darwins, at least right off. After all, pvc shrapnel isn't too heavy. You will have to test the system at a pressure greater than what you are likely to see in service. Your safety margin is only a factor of 2. Can you move to schedule 80 pipe?

That tap is going to be a weak spot. If it decides it doesn't like it there, it will leave the tank in something of a hurry.

I don't know if this is an acceptable setup. Given the effects of fatigue, and the connections, I would have my doubts.

[Unisaw A100]

I really don't think this would be enough for a Darwin Award unless maybe you went an extra step or two and glued extra shrapnel to it like maybe screws, nails, shards of glass.

Then again, it could just be me.

UA100

[Norman D. Crow]

Phil, You've made your case in this one statement, then go on with yada, yada, yada.

Please, please, please! Go to

hits regarding PVC(a few NOT about compressed air).

How many times has this group gone over this same ground in the last year?

PVC is NOT repeat NOT suitable for compressed air!

The basic facts are that fluids under pressure and gases under pressure are two different entities, and containment for one may not be good for the other.

[Phil Crow]

Thanks, Michael, et al. That's the kind of response I was looking for. Reasonable, succint, informative.

I hadn't considered the deterioration issue, particularly from oil.

The reason for the post, originally, was that I had a chance to pick up some 8" SCH 40 pipe for the right price, and figured that the air tank idea was worth considering. Also, the 'hang it from the ceiling' aspect is appealing. Well, back to the drawing board.

As for the rest of you, if I'd have wanted the abuse, I'd have stayed home and talked to my mother in law.

-Phil Crow

[Ed Clarke]

Catastrophic failure would be unpleasant. I asked in one of the physics groups about energy storage in a compressed air tank. My 80 gallon tank contains about the same amount of energy as a stick of dynamite.

There's a reason why no manufacturer makes a plastic pressure tank. Even those "bladder" well tanks are metal.

[Bill Rogers]

These messages are not posted with the expectation of a reasonable response. They are just pretending to be Tim the Toolman Taylor (Woo woo), looking for a kneejerk.

Bill.

[Greg]

except the other half that are fiberglass.

[Dave Hinz]

...which isn't PVC either... Yes, fiberglass tanks are great, we use them for our airpaks for the fire department. 2215 PSI rating, much lighter than steel. Of course, they're 3 times the price, but when you're carrying it around for 20 minutes, weight matters. For a air storage you don't have to move around, steel is still cheaper.