In the HRSG system will the Deaerator located in the LP section above the LP drum commonly fall under the requirements of Section I ? Or will the boundary end with the LP drum and the DA be considered as an attachment?
It really depends on the location and valving. If not isolated outside the ASME I boundary, it will be governed by ASME I. We have seen them designed, manufactured and stamped per ASME I and ASME VIII, Div. 1.