Heat Exchanger Query

Dear All, I am working in a consultancy these days and m a fresh graduate from Mechanical. I m stuck at a place while designing Heat Exchanger. My queries are 1. Whats the criteria/standard for choosing the diameter of rear shell cover in case of Floating type (S) Exchanger. I got a feedback from some other platform that TEMA suggest the diameter of rear shell cover. I have gone through to the Seventh Edition but couldnt find that. In case if there exist design practices, i will appreciate if someone can suggest me any recommended practice. 2. What is the normal design practice when we choose APPENDIX 2 Flange. For floating type heat exchangers, i have used Appendix 2 flange for rear head flange,rear shell cover,tube side flange (rear) and shell side flange (rear). I have gone through ASME APPENDIX 2 but didnt find any design practice or standard. I mean wats the normal ratio b/w go and g1?? wat abt hub diamter,thickness, ecentricity and bolt circle diameter?? I m new to the designing field. I would appreciate if someone come up with the answers.Also if someone provide me the link where i can read some stuff relating to designing of Floating type Heat Exchanger..

Regards,

UBA