B16.5 150# socket weld flanges greater than 3" NPS

[civnavyeng]

I need some assistance in determining what guidance exists for B16.5 socket weld flanges greater than 3" NPS for military (navy) use. I'm dealing with a ship system diagram that calls for "B16.5 RF 150# SW" flanges for 2"-6" NPS sizes. B16.5 provides dimensions for socket depth for SW flanges up to 3" NPS but not greater. Various suppliers show socket depths for SW flanges greater than 3" but what is that based on?

 

[DSB123]

civnavyeng,
I think you should be opting for slip-on flanges for sizes above 2"nb. Socket weld flanges are generally not used above 2"nb.

 

[civnavyeng]

While I concur that a slip-on flange would be the better choice for this size, I have limited authority to "re-design" the system (spec calls for socket weld and not slip-on). I am working a job to replace a significant portion of the applicable system piping as a "repair".

 

[DSB123]

civnavyeng,
If the sizes are not in B16.5 what does that indicate???

 

[civnavyeng]

DSB123,
Thanks for stating the obvious. You have successfully grasped my problem.
- I have a system spec that calls for a flange size/type is not authorized by B16.5, yet there are numerous suppliers that provide these "B16.5" flanges and all appear to use the same dimensions for socket depths on flanges greater than 3" NPS. Which brings me back to my original question. What is the basis for these dimensions?
- What I am trying to find is some sort of spec/letter/whatever (perhaps US Navy specific) that defines the dimensions and/or authorizes the use of these flanges which are outside of B16.5 specs. To date I have been unable to locate anything and that leaves me between a rock and a hard place.

 

[DSB123]

civnavyeng,
Have you grasped the answer though. "B16.5" flanges do not come in socket weld for sizes greater than what is designated in B16.5. Therefore your suppliers cannot call them B16.5 flanges if they are not in the Code.

 

[pennpiper]

I guess the only solution is to ask that guy with the Five Stars on the top floor of the "D" Ring of the Pentagon to tell you where to buy them.

 

[GenB]

in some non code work, designers specify socket weld but meaning slip-on,
field welder only ''socketweld'' only on the outside.

 

[civnavyeng]

Unfortunately the existing flanges in the system are indeed 6" NPS socket welded flanges (not slip-on) and are stamped B16.5. Also, there are numerous manufacturers/suppliers out there that list "B16.5" 150# SW flanges greater than 3" NPS in their catalogs (see

http://www.texasflange.com/dims/ansi B16 150.pdf

for just one) even though this is a violation of B16.5.

 

[GenB]

I am looking at B16.5, socketweld to 3in max.
Some shops machine to larger bore if ordered.
the B16.5 is there but look at the reading/stamping, it may should be a weldneck flange machined to socketweld.
If you are not bound to ASME, you could have it machined and you're home free.

genblr

 

[vesselfab]

not a weld neck flange machined
wrong hub shape

normally it would be a hubbed blind flange bored and counterbored

 

[GenB]

it shows a little, we did it in the pass and works on non-Code or other aplications where permitted.