Impact Testing Exemption for SA 266 Gr. 2 Tubesheet
Impact Testing Exemption for SA 266 Gr. 2 Tubesheet
(OP)
We are designing one S&T heat exchanger with Carbon Steel MOC.
The Design MDMT for shell side is -29 degree C.
Tubesheet MOC is SA 266 Gr. 2 & its thickness is 67mm.
We can not take Impact Testing exemption as per UG-20(f) as specified in the project documents.
When we designed the heat exchanger in COMPRESS we found that it is not considering reduction in rated MDMT for Tubesheet as per Fig. UCS-66.1.
However, the same is being considered for body flanges with same MOC SA 266 Gr. 2.
I shall be thankful if you kindly inform why COMPRESS is not considering reduction in rated MDMT for Tubesheet as per Fig. UCS-66.1?
The Design MDMT for shell side is -29 degree C.
Tubesheet MOC is SA 266 Gr. 2 & its thickness is 67mm.
We can not take Impact Testing exemption as per UG-20(f) as specified in the project documents.
When we designed the heat exchanger in COMPRESS we found that it is not considering reduction in rated MDMT for Tubesheet as per Fig. UCS-66.1.
However, the same is being considered for body flanges with same MOC SA 266 Gr. 2.
I shall be thankful if you kindly inform why COMPRESS is not considering reduction in rated MDMT for Tubesheet as per Fig. UCS-66.1?
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RE: Impact Testing Exemption for SA 266 Gr. 2 Tubesheet
RE: Impact Testing Exemption for SA 266 Gr. 2 Tubesheet
I am attaching the COMPRESS Design file herewith.
RE: Impact Testing Exemption for SA 266 Gr. 2 Tubesheet
RE: Impact Testing Exemption for SA 266 Gr. 2 Tubesheet
Cheers
RE: Impact Testing Exemption for SA 266 Gr. 2 Tubesheet
Our Tubesheet MOC is not normalized & falling under Curve B.
However, my query was why COMPRESS is not considering reduction in rated MDMT for Tubesheet as per Fig. UCS-66.1.
Because if it considers this exemption, there will not be any requirement of normalizing & fine rain practice.
That is because minimum required thickness of tubesheet is very less as compared to provided thickness.
Here, we need to provide higher thickness for tubesheet so as to accommodate collar bolt arrangement as per API 660.
RE: Impact Testing Exemption for SA 266 Gr. 2 Tubesheet
RE: Impact Testing Exemption for SA 266 Gr. 2 Tubesheet
Noted that in our case flange is exempted.
However, My query was regarding Tubesheet.
I wish to know why COMPRESS is not considering reduction in rated MDMT for Tubesheet as per Fig. UCS-66.1.
RE: Impact Testing Exemption for SA 266 Gr. 2 Tubesheet
RE: Impact Testing Exemption for SA 266 Gr. 2 Tubesheet