first you must check upstream device code
for example Tank/API 650 as below:

1: this standard have a maximum/minimum range for vacuum and design pressure. check it.(Appendix F and Appendix V)
2: this standard have to criteria that if you be below of them you don't need special Design.(Appendix F and Appendix V are special design)
2.1: Internal pressure below weight of roof (you must know a plate with 5mm thickness have 50mmH2O pressure in 1 m2 according to metal density)
2.2 : Normal operating external pressure Doesn't exceed 0.25 kPa

you get sufficient data. design please.