Modified Flanges as Listed Components
Modified Flanges as Listed Components
(OP)
Can modified B16.5 flanges be used as Listed Components within a B31.3 piping system?
In particular I have a 2" blind flange that I want to bore through and slide a 1" tube through and fillet weld on both sides. Also I have several 1", 1½", and 2" lap joint flanges that need to be bored out to fit over a lap joint stub end. Thicknesses of the flanges remains the same and sealing surfaces are not impacted.
Any input is appreciated. Thanks in advance.
In particular I have a 2" blind flange that I want to bore through and slide a 1" tube through and fillet weld on both sides. Also I have several 1", 1½", and 2" lap joint flanges that need to be bored out to fit over a lap joint stub end. Thicknesses of the flanges remains the same and sealing surfaces are not impacted.
Any input is appreciated. Thanks in advance.





RE: Modified Flanges as Listed Components
RE: Modified Flanges as Listed Components
I would still have an issue with my lap joint flanges, however. The heart of my question is whether I can modify B16.5 flanges and still use them as B16.5 flanges as long as I don't affect the thickness or the sealing surface. I have done it before, but not in a piping system that was subject to B31.3.
RE: Modified Flanges as Listed Components
Regarding your 1" connection in a 2" blind flange: Take a close look at Table F6 on page 162 of the 2003 edition of B16.5. You're basically fabricating a reducing flange from a blind flange. If you had a 3/4" connection in the 2" blind, you would be fine with no further design changes in accordance with Note 1.
On the other hand, a 1" connection requires a hub. But the hub on a slip on 1" flange is roughly 1/8" high so that your fillet weld probably creates the hub which is required anyway. But now you're effectively doing a weld buildup to create this flange and I'm not sure that that's explicitly ok...
jt
RE: Modified Flanges as Listed Components
What I don't understand is why wouldn't your stub ends fit into their corresponding ASME B16.5 lap joint flanges. What standard or specification are your stub ends designed to? Are they in accordance to ASME B16.9 or are they fabricated in accordance to ASME B31.3?
RE: Modified Flanges as Listed Components
http://www.resistoflex.com/rotateflange.asp
RE: Modified Flanges as Listed Components
I am quite positive that the rotatable flange assembly by Crane Resistoflex meets ASME B31.3 requirements. Why don't you ask them if their components are manufactured in accordance to one of the standards in Table A326.1?
RE: Modified Flanges as Listed Components
We routinely modified flanges for Resistoflex Piping Systems and If I recall the amount of metal removed to accommodate the stub end was quite small. Again if I recall correctly the final ID was just outside the tolerance of the flange as per code.
RE: Modified Flanges as Listed Components
RE: Modified Flanges as Listed Components
If I modify a standard 16.5 flange can I still use its temperature-pressure ratings as a listed component or does it then become an unlisted component that I have to verify using section 304.7.2?
RE: Modified Flanges as Listed Components
EJL
RE: Modified Flanges as Listed Components
Regards, John.
RE: Modified Flanges as Listed Components
JohnBreen - Thanks. I would have used a reducer, but it was going form tubing to piping so they were harder to find and this could be made easily. It has since been built so I have to figure out a way to qualify it now.