Penalty for Split Nozzle Pads per UG-37(h)

What’s worse than using segmental nozzle reinforcement pads to meet UG-37 area-of-replacement requirements? Only getting 75% credit for the pad area.

People ask me all time to review nozzle calculations and one mistake I often see is with split or segmental nozzle reinforcement pads with weld orientations lined up with the longitudinal axis and with no way to inspect them. I fail a lot of nozzles this way when the reinforcement pad does not give the design engineer the credit for the area that they expect. 

That’s right. If you do not satisfy the requirements of UG-37(h)(1) or UG-37(h)(2), only 75% of your nozzle reinforcement pad area may be used in A5. This means that the design engineer needs to put some thought into the design of the reinforcement pad and weld. 

Please refer to UG-37(h) for more information regarding segmental reinforcement pads.