Sandbag as Permanent Pipe Support
Sandbag as Permanent Pipe Support
(OP)
A 42" line-break valve has a 2" sensing line which shall be branched min. 5D downstream in an underground gas pipeline. 2" branch shall be done at 12 o'clock. Is it acceptable (from engineering point of view)to use sandbags under 2" pipe (as it is shown in the below picture) permanently and backfill the line?


Nothing is more fairly distributed than common sense: no one thinks he needs more of it than he already has. Rene Descartes





RE: Sandbag as Permanent Pipe Support
David Simpson, PE
MuleShoe Engineering
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist
RE: Sandbag as Permanent Pipe Support
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers
RE: Sandbag as Permanent Pipe Support
RE: Sandbag as Permanent Pipe Support
RE: Sandbag as Permanent Pipe Support
RE: Sandbag as Permanent Pipe Support
The problem with sandbags are the sand is not contained. If I bed a pipe with sand, the sand is contained by the ditch walls and the rest of the fill. With sandbags the sand migrates laterally toward the minimal stress in the backfill. When we dig it up the sand is never far from the pipe, just not under it.
rconnor,
I've seen that too, we never seem to get the bedding right and the pipe is cantilevered between the supporting blocks. When you try to use sandbags to keep the pipe off the ditch (and I see that too often in fiberglass) then when the bags fail, the unsupported lengths increase while axial movement is constrained, not a good combination in any pipe and results in way too many leaks in fiberglass.
David Simpson, PE
MuleShoe Engineering
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist
RE: Sandbag as Permanent Pipe Support
RE: Sandbag as Permanent Pipe Support
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers
RE: Sandbag as Permanent Pipe Support
Brackets need to attach to a structure. Dirt is not a structure.
But you know that.
If you're thinking, 'attach the little pipe to the big one via brackets', then the brackets become stress raisers on the big pipe, and the dirt becomes an irresistible force, using the brackets to damage the big pipe.
Mike Halloran
Pembroke Pines, FL, USA
RE: Sandbag as Permanent Pipe Support
There are a few firms selling structured pipeline support pillows. BASF has a product:
http://www.polyurethanes.basf.us/applications/segm...
PipeSak Inc. also has a product:
http://www.pipesak.com/support/default.aspx
Unopened bags of quickcrete are a Contractors ppor substitute for an engineered thrust block.
RE: Sandbag as Permanent Pipe Support
RE: Sandbag as Permanent Pipe Support
You can do many things with 3D modeling software (such as SW), but it not normal in piping.
I got very helpful discussion here and I highly appreciated your advice, my friend.
Nothing is more fairly distributed than common sense: no one thinks he needs more of it than he already has. Rene Descartes
RE: Sandbag as Permanent Pipe Support
Some of this is due to movement, corrosion ( wall thickness is usually much less than the main pipe) and stress concentration at weldolets, elbows etc. They are also virtually impossible to inspect once installed. Remember to electrically isolate it so it doesn't ground the CP system...
If this was me I would make the small pipe vertical, encase it in a PE or similar pipe about 3 pipe sizes bigger and fill the annulus with pea gravel. I would also consider making the connection 100mm then reducing t0 50mm to give the connection some strength. Those two 90 degree elbows could easily become overstressed with even a small amount of compaction or "leakage" of the sand bags
In answer to the original question, No, it's not acceptable for all the reasons given above. If you have to do it this way then piggyback it using proper blocks like they do subsea, probably at about 500mm centres.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Sandbag as Permanent Pipe Support
What does that mean, when this sensing line is going to attach to the LBV somewhere above ground?
BTW, What about using a pickup strap clamp?
Nothing is more fairly distributed than common sense: no one thinks he needs more of it than he already has. Rene Descartes
RE: Sandbag as Permanent Pipe Support
Same thing applies to the valve, but often the stem is electrically isolated from the valve to prevent this.
your clamp as shown is even worse than a sandbag as it provides a concentrated point load. The piggyback clamps shown in the post above would need to be nearly continuous in this instance to provide sufficient support to that rather weedy little line.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Sandbag as Permanent Pipe Support
This surprised me, because that 42" LBV is a trunnion-mounted ball valve with anti-static system which let electric charges being discharged from ball to the body via stem.
Nothing is more fairly distributed than common sense: no one thinks he needs more of it than he already has. Rene Descartes
RE: Sandbag as Permanent Pipe Support
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Sandbag as Permanent Pipe Support
Nothing is more fairly distributed than common sense: no one thinks he needs more of it than he already has. Rene Descartes
RE: Sandbag as Permanent Pipe Support
Buried pipeline valves become part of the pipeline CP system and need to be coated / painted to prevent corrosion and current loss, but it is important that anything (like your 2" line) electrically connected to the pipeline is isolated and not earthed.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Sandbag as Permanent Pipe Support
Nothing is more fairly distributed than common sense: no one thinks he needs more of it than he already has. Rene Descartes