View Full Version : Engineering Question BSP vs Tubing

01-05-2011, 10:28 PM
Being on the wrong side of the pond makes getting BSP pipe near impossible..
2 1/2 in particular.
The OD of the the BSP is the 'killer' being 3".
The ships I work on were all made/built in Europe...so all have BSP
They mostly use straub couplings that have a +/- of 1 mm for the OD
That's were the problem lies.
Ameriacan 2 1/2" pipe has an OD of 2.875"...and it is too small for the coupling.

I found some SAE 316 Stainless tube that has an OD of 3" and a wall of 0.120"
The BSP is 3" od with a id of approx 2.5" so there is a 0.160" difference.
My question is, will this tubing act as a sub for the BSP
Working Pressure is approx 10 Bars at the max and I would be replacing Copper/Nickle with SAE 316 Stainless.
These would act as a patch type repair until the replacement tube come in from Europe.
Your thoughts please
ps. no legal/ liability arguments etc...LoL

Mike Burch
01-05-2011, 10:51 PM
Might there be corrosion issues with cupro-nickel meeting 316? Temporary fixes on ships have a habit of becoming permanent, and the long-term effects could be interesting, depending on what goes through the pipes.

01-05-2011, 10:55 PM
As far as I am aware, pipe (or Circular Hollow section) is probably the same the world over..

When I buy pipe here I can buy it with various wall thicknesses, but the ID remains the same for each wall thickness... It used to go by colour bands

Green Band was the lightest
They Yellow Band
Then Blue Band which is the old water pipe.
Then Red Band
And I think there is white band as well...

I think the US goes by the "schedule" of the pipe..

Don Young
01-05-2011, 11:00 PM
I don't know of anything in particular but there is a world of pipe/tubing available besides common US NPT pipe. I would think a search of industrial suppliers would yield a 3" OD tube with 0.250" wall, particularly in structural or high pressure hydraulic tubing.

01-05-2011, 11:39 PM
Would any supplier have cupro-nickel condenser tube.? It should be available in a range of wall thicknesses. In this case, look for 3" OD tube with a suitable wall thickness. You will probably have to take a full length AND leave your first-born as a deposit.

01-06-2011, 06:41 PM
Thanks, but no luck so far...
ps Guys has to be stainless or copper/nickel
Steel tube, which is available,will not work.

01-06-2011, 06:46 PM
Did some research and to my surprise pipe made in the US is a different size to pipe made elsewhere in the world.... Pipe made to 2 1/2 BS standards is indeed just a smidgen under 3" while US 2 1/2 pipe is a fair bit under 3"

01-06-2011, 07:03 PM
2 1/2" BSP is 3" od
2 1/2" american pipe is 2 7/8"
Couplings are +/- 1mm and the difference is 0.125" or 3 mm
i.e. Too fcuking small...LoL

01-06-2011, 09:00 PM
So get a chunk of 3" schedule 160; turn it down to 3" OD from the original 3.5"OD

You may have to open up the ID as it will be 2.624".

01-06-2011, 09:08 PM
Been there and done it....
and have made pcs from solid 3" sae 316...
it gets to u.... esp when it's 14" long and they need it asap..LoL
Just a 10' piece of 2 1/2" BSP stainless...ready to sell my soul..again..LoL

01-07-2011, 01:05 AM
You might try Dover Tubular or Prudential Tube, I tink they are both in New Jersey. You ought to be able to find 316 seamless ASTM A213 or 211 in 3" od x .250 wall, possibly .188 as well. They both used to cut to size also.

Stay away from the structural, it is not welded to be safe for pressure.



01-07-2011, 06:24 PM
Try these Eddie.