Manifolds or headers questions
Manifolds or headers questions
(OP)
Is there a rule of thumb for welding manifolds or headers that use compressed air? I am sure there is a simple answer, but I don't know where to look, that is why I am asking here. I have two size manifolds that I need to fabricate, but I am think it needs to be done by a certified shop. These are 3"x 3" x 36" tubes 1/4" wall that will have six 1/2" NPT couplings, and two 1" couplings welded to the tube. There will also be a supply end that is 2-1/2" and mounting brackets to attach to a machine. The other would be 6 'x 6" x 54" tube 1/4" wall with three 1-1/2" NPT couplings and a supply and petcock.
I guess what I am asking is there a formula that is used to figure if these are to meet ASME standard or is this exempt from ASME?
I guess what I am asking is there a formula that is used to figure if these are to meet ASME standard or is this exempt from ASME?





RE: Manifolds or headers questions
RE: Manifolds or headers questions
RE: Manifolds or headers questions
RE: Manifolds or headers questions
Some shops , companies, and insurance underwrites require that if the vessel operates above 15 psig, it will need an ASME stamp, or at least some proof that it was designed , fabricated and tested per ASME requirements. For the 54" manifold, a hydrotest at 130% max expected operating pressure would certainly be needed.
"Whom the gods would destroy, they first make mad "
RE: Manifolds or headers questions
RE: Manifolds or headers questions
I understand completely- I have seen fab shops that fabricate their own compressed air manifolds on the spot with no design check, no QC, no hydrotest.It happens frequently. But when you get to 54", it is necessary to get it right.
"Whom the gods would destroy, they first make mad "
RE: Manifolds or headers questions
Is there a typo here ?
Why would you not use a pre-certified commercial grade item ?
http://hansontank.us/airtanks.html
MJCronin
Sr. Process Engineer
RE: Manifolds or headers questions
The think is to either cut the pipes free and get everything inline, then make a template to shoe position of each coupling. The customer is feeling this is just to much thinking and amount of work. They have made their own manifolds in the past, but there is some reason why they are not now that I don't know of. My feeling is to have a certified shop make everything or to just stay away from that job.
If you think this is bad, look at my other post about Pressure Vessels alterations
http://www.eng-tips.com/viewthread.cfm?qid=385044
RE: Manifolds or headers questions