NOZZLE NECK MADE FROM PLATE

[ROMEUM2]

Hi all,

I have a doubt if we can use a nozzle neck made from plate for a new nozzle in API 650 tank existing. It will be the first time that we do it to use a plate for a new nozzle according to API 650. I hope someone can help me.

Thanks in advance,

 

[JStephen]

Yes, nozzle necks may be formed from the plate. The choice of whether to use seamless pipe or formed plate is usually economic, depending on availability and cost of the desired pipe and availability of roll-forming equipment for small diameters.

 

[IFRs]

Manway necks are most commonly made from rolled plate. As JStephen says, the code allows, it is an economic decision. See API 650 4.5.2, which reads in part: "material for shell nozzles and shell manhole necks shall be seamless pipe, seamless forging, [highlight #FCE94F]or plate material[/highlight] as specified in 4.2.10.1."

 

[valleytank]

I've done it on built-up manways but I'm just curious why in this situation you are requested to fabricate a nozzle neck out of rolled plate. Its perfectly fine but in most cases some seamless A106B will suffice.

 

[Syahar1975]

Like Valleytak said, for the roof and shell manholes neck are very common fabricated from the plate.

I believe fabricate shell nozzle by ex stock pipe is cheaper than a plate.

 

[JStephen]

Some reasons why you might want to- if it's a size not available in seamless pipe, or if you'd be obligated to buy 20' or 40' of pipe to get the little piece you need, or if it's stainless steel/cold weather grades, or if the pipe is available halfway around the world for a small fortune and the plate's right there...

 

[Anand23404]

For pipe size of 12" and more you can use plate material for nozzles. That's the break even point considering economics