Schedules for LWN nozzles
Schedules for LWN nozzles
(OP)
I have a doubt regarding the pipe schedule for LWN nozzles. As per BP specification for pressure vessel "it states that all connection 2" and below shall be LWN" and other clause is that all the connection below 2" shall have a minimum schedule of 160.As per my understanding all the LWN nozzles are forged type so they shall not have anything like schedule only thickness shall be mentioned while making the datasheet.
Now what is the interpretation of the above two contradicting clause. How can I provide Schedules for LWN nozzles.
Please explain this situation
Now what is the interpretation of the above two contradicting clause. How can I provide Schedules for LWN nozzles.
Please explain this situation





RE: Schedules for LWN nozzles
RE: Schedules for LWN nozzles
RE: Schedules for LWN nozzles
So if u have solution to my query please share
RE: Schedules for LWN nozzles
LWNs are provided with a typical OD - the ID is specified on the purchase order.
If you need to comply with Sch 160 requirements you purchase all your LWN's with an ID to match the respective Sch 160 ID it is being connected to.
The OD of an LWN is always bigger than a schedule pipe (as they are self reinforcing) so you will always comply with the Sch 160 minimum requirement for wall thickness.
Regards,
Shane
RE: Schedules for LWN nozzles
If you select LWN nozzles you will always meet both requirements, and will have one less weld to make as well.
Regards,
Mike
On Edit: If that were the worst contradiction I found in client specifications, my professional life would be much simpler & happier :)
RE: Schedules for LWN nozzles
As the Quality Co-ordinator it makes it hard to enforce something when it is so poorly written that the kindest thing you could do would be to put a match to it.
RE: Schedules for LWN nozzles
I agree the clause is a little odd and overdoing it a bit, but is does say sch 160 as a minimum, therefore it is not contradictory, only a little confusing.
The term Long Weld Neck, may well be in common usage, but the exact phrase which should be used is "straight hub welding flanges" see para 2.8 of ASME B 16.5.
The dimensions you need to check are for you particular flange class rating, the X dimension and the B dimension in the appropriate table in B 16.5
This will give you the wall thickness of a "LWN" flange. If its more than 8.74mm (the wt of 2" sch 160)-even class 150 is more than that-, then you've satisfied the requirement.
Not all connections on a vessel will have a flange - some could be welded pipe - depends on the duty and vessel so not quite as silly as it might sound at first.
So I would just call out a straight hub welding flange to ASME B 16.5, class XXX
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Schedules for LWN nozzles
Know the feeling :)
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: Schedules for LWN nozzles
- Straight nozzles - LWN
- Special nozzles - sch160 pipe.
Special nozzles I think of as anything where it isn't directly flanged. These are often nozzles with elbows attached such as on vertical vessels where the nozzle is elbowed horizontally.
RE: Schedules for LWN nozzles
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand