Tank Nozzle

[Forging09]

Is there any drawback if ERW pipe nozzle is used on the shell of atm water tank for more than 24" diameter size of nozzle?

Thanks in advance for assistance.

 

[JohnGP]

I'm not sure if your concern is about use of ERW pipe or size of nozzle, but there are many 36" (approx) nozzles on tanks at the site I'm presently at.

Above 24" your only choice may be ERW, so if the additional longitudinal weld is a problem then you need to mitigate it through choice of material, or applied protective coating.

Cheers,
John

 

[Forging09]

Hi John,
36" nozzle is from ERW pipe at site you are present?

 

[JohnGP]

I checked the MDR for one of the tanks, and the 30" and 36" nozzle necks were actually rolled from plate and welded. Material is SS316L so availability of pipe in those sizes may have been an issue.

Cheers,
John

 

[IFRs]

Have you checked API 650 section 4.5 for the material specifications for pipe? For instance, it says "material for shell nozzles and shell manhole necks shall be seamless pipe, seamless forging, or plate material as specified in 4.2.9.1." which seems to allow rolled plate. Section 4.2.9.1 reads in part "plates used for manhole and nozzle necks". It is common to use rolled plate for manway necks. Does the neck meet the material requirements of section 4.2? Does it meet any of the pipe specifications of 4.5?

 

[jte]

Just putting in a plug for the new forum1452 which may be more appropriate if the water tank in question is not fabricated to an API standard... Though I don't encourage double posting.

jt

 

[JStephen]

API requires either seamless pipe or rolled plate. If it's not an API tank, it's not necessarily an issue.