ABS vacuum rating 2

[Unotec]

I need to find out the pressure ratings for ABS piping.

I tried the ABS web page and no luck. Googled it and no luck either.

Basically, I have 3", sched40 ABS piping for a vacuum application. I need to know how much vacuum this pipe can handle.

Full vacuum maybe?

Does anyone know where I can find the answer?

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[Unotec]

Yes, it will be partial vacuum, I am aware. The issue is some of the guys here are so... detailed, that they want assurance that the pipe can handle full vacuum.

I would not expect less than 300mmHg. In any event, the site has agreed to put a piece of pipe at the vac's hose and giv'er!!

I do not expect it to collapse. By the way, I chose to use the PVC piping instead due to material compatibilities.

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[btrueblood]

Montemayor,

What kinda money you throwin' down, I want some of that action too.

 

[Compositepro]

Don't overlook the fact that temperature will have a very dramatic effect on the vacuum strength of any plastic pipe, as would even slight solvent exposure.

 

[Unotec]

Well, if you wanna bet, here are the specs:
PVC 2" sched 40 pipe
Vac's capacity 0.3 atm (at best)Temp: about 15ºC
No fluid will be sucked during the trial

But I'm the broker, so I take 10% on the bets, eh!

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[JLSeagull]

AND ...
...just in case anyone missed it ...
... ... in my response after Biginch mentioned his error ...
... ... a smiley face exists next to my post mentining the ABS (American Bureau of Shipping) certification requirements for FRP piping. ;-)

I appologize if it was not sufficiently obvious. Where are the Brits when one tries to invoke a bit of humor anyway?

 

[BigInch]

Oh???
Ya!
You're killing me here.

British humor at its finest;-)

-------------------------------
I'll take on all comers at 10:1 that a 2" x S40 PVC survives whatever vacuum that truck can put on it at 15ºC, provided its round when you start the test. Now's your chance.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[badservo]

We use 6" PVC sewer pipe (SDR-35 3034 stamped on pipe) for vacuum(air only). It has cycled between 5 to >28 inHg about 50 times a day for the last 10 years with only 2 problems.

1: 3ft. long pipe connecting to pump was slightly oval, work fine for about 6 months before imploding.

2: capped the end of a 30ft. long pipe with an elbow at the other end, then another 8ft. of pipe and a tee. worked for a few years before the cap imploded and traveled fast enough to bust thru the elbow and the tee, sending several pieces of pvc into the insulation on the wall.

Never had a problem with 2 inch or smaller.

 

[BigInch]

There goes my money.

A 2"xS40 should be good to about -279 psi.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[786392]

Since all the Giants are speaking out loudly what they feel justified.

There isn't much room for 'newbie's ' like me uttering their tiny voice(s)

Still I add little bit; The case for vacume application of plastic pipes might be and most usually is 'TRUE'

only for smaller diameters and Not very long pipeline lengths at near ambient temperature(s) of moderate weather conditions.

Hope this summarizes.

Best Regards
Qalander(Chem)

 

[JohnBreen]

Look at the Plastic Piping Handbook by Dave Willoughby. He addresses "critical external pressure" and love's equation. If you have the needed properties of the pipe material you can determine the external load (from pressure or overburden) that will cause unconstrained buckling of the wall. Using 14.7 psig as the external load would be VERY conservative.

John

 

[Unotec]

Actually, there will be no external loads (other than the air pressure). The pipe will be used as an extension to the vacuum hose for cleaning tanks without going inside them.

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[JohnBreen]

When you have a partial vacuum in a cylinder the outside atmospheric pressure IS AN EXTERNAL LOAD.

 

[Unotec]

I agree, thus my comment in brackets.
However, being completely ignorant of the book you referred before, will not those equations consider external loading as the weight of the soil?
This is unchartered territory for me, but as I see things, you will have the load of the earth on a buried pipe compressing it; while at the same time, it will help prevent the pipe from losing its roundness.
In my case, nothing would prevent the pipe from losing its shape other than its own mechanical strength.
Well, I guess you can also consider the atmospheric pressure the same as the earth loading.
This is a one time for me, so I do not think I will buy the book, but I will keep it for reference.
Thanks

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[rconner]

Just a couple comments, as I've gotten a kick out of following all the emoticons on this one! While I'm not sure exactly what you mean by "fuel oils", you might want to double-check to make sure they are compatible with the specific "pvc" you are considering (not saying this is the case here, but I believe some spills of contaminants etc. have been the result of assumptions/perceptions of inertness to the chemicals, that were really not there for the specific long-term exposure). Also, I believe in any buckling or collapse-resistance design or tests involving such piping, you should make sure the elastic modulus etc. you assume in the calculations is suitable for the temperature and term or duration of load application. At room temperature e.g. a short-term elastic modulus say e.g. of ~400,000 psi might reduce to an apparent modulus of 140,000 psi or so if loads were applied inexorably for many years. Also, even a (at least short-term) collapse test of plastic pipes subject to creep may not necessarily predict security, if the actual service includes longer-term (and/or potentially higher temperature?) external load application.

 

[Unotec]

rconner, I appreciate your comments and realize I should be more specific on the 'fuel oils'... waste laden crap is it's unofficial name. It is basically the left over solids from waste oil recovery.

It comes from waste most producing facilities and tank farms have. It ends up in our tanks, we recover as much oil as possible, which is mainly crude of very varied characteristics, and the solids left at the bottom of the tank, in every turn around, are cleaned with the vac truck.

So this pipe will man handled all the time. Basically I want just to make sure that the operator does not loose the gloves or coveralls while sucking the bottoms.

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[786392]

Dear Unotec,
Somehow I am not inclined to accept that the plastic pipes may have sufficient withholding strength to stand vacuum conditions in real situations.Unless specially designed for the service.

As we have seen vacuum conditions disastrous effect in industry on many otherwise strong vessels/tanks/containers subjected to vacuum conditions incidentally or unplanned(without specific design) etc.

However the particular service application you referred in most recent posts involving partial vacuum may be practical although with a much shortened life cycle.

Hope this helps.

Best Regards
Qalander(Chem)

 

[BigInch]

REPEAT!

It will withstand -280 psi as long as you can keep it round, manhandling stresses low, and the rest of the properties intact.

That's equivalent to like 19 atmospheres of "vacuum".
I think it'll work for long enough.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[Unotec]

I cannot find a blasted emoticon handing cash, because my bet is with you BigInch.

I know my truck will not even achieve full vacuum, but... other than theoretically, can you actually achieve vacuum below 0mmHg? (on earth)

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[Unotec]

Well, yes, I guess at the bottom of the ocean you would

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[BigInch]

Pipe doesn't care if you want to call it a vacuum below absolute or external pressure. It just changes its hoop stress from the usual tension from internal pressure to compression for external pressure.

How's this one?

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/