Reinforcement pad Decision 1

[armanswitzher]

dear all,
i confuse about how to decide to use reinforcement pad or not in nozzle/opening. what is the criteria?
i asked same people and most of them have different answer. some of them said that reinforcement pad required if the nozzle size more than 2 inch. the others said that it depend on shell thickness. what's is the right answer based on code?

thanks and regard

 

[TGS4]

Additional nozzle reinforcement for pressure containment is dictated by the Code of Construction. Whether or not you use a pad or an integrally-reinforced nozzle depends on other aspects such as fatigue considerations (repads are attached to the shell with fillet welds, which have poorer performance in fatigue).

 

[iamai1]

As an Authorized Inspector I frequently verify design prints and calculations. TSG4 is correct but when you ask this question you should refer to the Code of construction. ASME Sect VIII Div 1:2011 UG-36(c)(3)(a) does list exemptions for limits of reinforcements for small nozzles. There are a number or variables which must be met, shell thickness among them. "Openings in vessels not subject to rapid fluctuations in pressure do not require reinforcement other than that inherent in the construction under the following conditions:" "Welded, brazed, and flued connections meeting the applicable rules and with a finished opening not larger than: 3 1/2" (89mm) diameter - in vessel shells or heads with a required minimum thickness of 3/8" (10mm)." But this is just the size requirements. The rules also contain limits for multiple openings and locations of the nozzles. So before exempting your nozzle per UG-36(c)(3)(a) read the entire section.