Threadolet Wall Thickness for Sect VIII Apps
Threadolet Wall Thickness for Sect VIII Apps
(OP)
Can anyone advise me on the subject? It seems to me that the wall thickness of this type of branch connection would depend on the run to which it is being welded.
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RE: Threadolet Wall Thickness for Sect VIII Apps
"Fittings manufactured to this standard practice are designed to make a fully reinforced branch connection in accordance with applicable piping code requirements, when attached, at an opening in a run pipe by means of a full penetration weld."
Table 1 of this standard provides information on which class of O-Let fitting is to be specified based on the schedule of pipe wall in use. It also notes that the use of run or branch pipe thinner or thicker than listed constitutes a deviation from the practice and then the fittings would essentially need to be custom designed and made to special dimensions agreed to by the Manufacturer and the Purchaser.
Note: in effect the standard is written under the general assumption that the branch pipe and the run pipe will have the same schedule (which was probably true long ago but with changes in code formula's doesn't hold today). However, if you specify the O-Let based on the heavier of the run and branch you should be conservative.
Here is a quick summary:
For buttwelding branches
Sch Std = Standard O-Let
Sch XS = Extra Strong O-Let
Sch 160 = Schedule 160 O-Let
For threaded or socket welding branches
Sch XS = Class 3000 O-Let
Sch 160 - Class 6000 O-Let
RE: Threadolet Wall Thickness for Sect VIII Apps
I suppose describing my particular proposed use might be in order. I have some guys that want to use up blind flanges we have in stock. These flanges need and instrument tap, and will then be attached to the end of a pipe header. Rather than use a full coupling, drilling and filleting both sides per Section VIII, they asked if the use of a threadolet might be possible. It seems as if it is. This would allow for a smaller hole, and welding from only one side. Understanding that the threadolet is designed to provide reinforcement as a piping branch, I would still like to calculate the available reinforcement in my application. Thus the need to know the wall thickness.
Actually, if I knew the full dimensional description of the threadolet, I wouldn't be asking the question. I could instruct the welders on a particular welding procedure and/or size if need be different from standard threadolet practice. Does this information also appear in B16.9? Unfortunately, I cannot find our company's copy.
In the future we will be using reducing flanges in this application. Frankly, I'm not sure why the shop doesn't want to use them now and save the blinds for another fabrication.
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RE: Threadolet Wall Thickness for Sect VIII Apps
WHY? you ask?
Because I am lazy and don't want to go through the calcs to say it's ok through blind.
RE: Threadolet Wall Thickness for Sect VIII Apps
Myself, I'd look at the actual thickness of the blind XX inches and then see if this corresponded to some schedule of pipe (Say 24" Sch XXS). If you could find a piece of pipe that was thicker than the blind and then buy an O-let rated for that pipe, it should provide sufficient reinforcement for the blind as well - I think ?
RE: Threadolet Wall Thickness for Sect VIII Apps
RE: Threadolet Wall Thickness for Sect VIII Apps
RE: Threadolet Wall Thickness for Sect VIII Apps
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Fitter, happier, more productive
RE: Threadolet Wall Thickness for Sect VIII Apps
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Fitter, happier, more productive
RE: Threadolet Wall Thickness for Sect VIII Apps