Manhole and Handhole Requirement

Is this an ASME vessel or are you building this pressure vessel to another set of rules ?

As per ASME Pressure Vessel Code Section VIII div 1, UG-46 :
"All vessels 18 in. (450 mm) to 36 in. (900 mm), inclusive, I.D. shall have a manhole or at least two handholes or two plugged, threaded inspection openings of not less than NPS 2 (DN 50)."

https://www.eng-tips.com/viewthread.cfm?qid=402958

I believe that you may need at least two handholes .....

that vessel is new build, and realized there is only one handhole provided instead of manhole.

you are right that there is possibility to provide two hand hole (4 in) as per UG-49 f).

thanks

Liquid traps malfunction, people can misunderstand or ignore analyzer readings, so there is good reason to expect moisture in the tank, rather than an application such as an argon processing plant where water contamination might be unexpected. Where a weld failure might lead to loss of life or property, not good to skimp on provisions to make inspection easy & fast. Just good common sense, for your business.

<...Any one can assist ...>

Yes. The Engineer/Surveyor for the company that is providing burst/collapse indemnity insurance cover on the equipment can certainly assist. Telephone?