Section IV: Welding of fittings to Tube Sheet

[bithack]

Section IV (HW-731.6 Fittings) restricts the attachment of flange-type fittings 3" NPS or less (without additional reinforcement) per figure HW-731 (sketch w-4) to a boiler "wall" thickness of 3/8" or less. Figure HW-731 refers (in title) to "....Connections to Shells, Drums, and Headers". Does this apply to the tube sheet (thickness) as well? (i.e. a 2 1/2" NPS flanged type fitting per HW-731 (sketch w-4) would not be able to be used on a 3/4" tube sheet without additional reinforcement).

 

[GenB]

Correct, a tubesheet is part of the drum. Addl calcs are needed to provide reinforcing of the nozzle. Its a common procedure.