2" LWN in lieu of 2" CPLG for Sec8 UG-46(f)
2" LWN in lieu of 2" CPLG for Sec8 UG-46(f)
(OP)
Do two 2" LWNs satisfy the Sec 8 Div 1 inspection opening requirement on a 36" ID vessel?
My vessel falls under UG-46(f)(2):
"All vessels 18 in. (450 mm) to 36 in. (900 mm), inclusive, I.D. shall have a manhole or at least two handholes or two plugged, threaded inspection openings of not less than NPS 2 (DN 50)."
I read this as, vessel shall have one of these three:
Others read it as shall
Under my interpretation, a pair of 2" LWNs with a 2" finished opening would not qualify as a threaded inspection opening of NPS2. It would also not meet UG-46(g)'s definition of a handhole (2" x 3" minimum opening).
Under others' interpretation, it is NPS 2 or larger and it is reserved as an inspection opening.
Others' argument makes sense to me, the opening on the 2" LWN (2.0in) is larger than that of a 2" 6000# coupling (1.7in), but I just cannot get my brain to read the code the way they are reading it.
My vessel falls under UG-46(f)(2):
"All vessels 18 in. (450 mm) to 36 in. (900 mm), inclusive, I.D. shall have a manhole or at least two handholes or two plugged, threaded inspection openings of not less than NPS 2 (DN 50)."
I read this as, vessel shall have one of these three:
1) manhole
2) two handholes
3) threaded inspection NPS 2
2) two handholes
3) threaded inspection NPS 2
Others read it as shall
1) have an opening not less than NPS2
2) it can be a manhole, two handholes, or a threaded inspection opening
2) it can be a manhole, two handholes, or a threaded inspection opening
Under my interpretation, a pair of 2" LWNs with a 2" finished opening would not qualify as a threaded inspection opening of NPS2. It would also not meet UG-46(g)'s definition of a handhole (2" x 3" minimum opening).
Under others' interpretation, it is NPS 2 or larger and it is reserved as an inspection opening.
Others' argument makes sense to me, the opening on the 2" LWN (2.0in) is larger than that of a 2" 6000# coupling (1.7in), but I just cannot get my brain to read the code the way they are reading it.





RE: 2" LWN in lieu of 2" CPLG for Sec8 UG-46(f)
One difference I see between a 2" coupling and a 2" LWN is the radial offset from the vessel, and in turn the amount of the inside surface of the vessel that will be visible. The 2" coupling puts you much closer to the vessel, giving you a steeper viewing angle down the longitudinal axis of the vessel.
I'm also very curious to hear the perspective of other forum memebers.
RE: 2" LWN in lieu of 2" CPLG for Sec8 UG-46(f)
RE: 2" LWN in lieu of 2" CPLG for Sec8 UG-46(f)
I did mess up the ID of the 2" coupling. I looked at the bore of a socketweld coupling and assumed it was the same for a threaded coupling. Thank you for catching that.
So that lends more validity to my stance that a 2" LWN would not equate to a 2" coupling.
Good enough for me, unless someone else can reply "yeah, we always use 2" LWN handholes and our AI loves them!"
RE: 2" LWN in lieu of 2" CPLG for Sec8 UG-46(f)
Will admit to some prejudice; I inspect them and fix them, but have only built a few. And a cplg is cheaper and easier to install. But it is close to useless to evaluate the interior.
RE: 2" LWN in lieu of 2" CPLG for Sec8 UG-46(f)
Cheers,
gr2vessels