PetroStreet

please share with me good references to study about inspection of storage tanks. 13 years experience within inspection without a direct storage tanks inspection assignment before. Know the basics though and now want to have advanced knowledge

Better to take a start directly with API 620 & 650.
They would provide you with practical applied knowledge.
Beneficial for you and if there is anything not rightly understood, you can consult your seniors.

Thanks for your quick response.\nyes, any support material if you recommend along with code study and application?

Reading out API 650 & 620 should be the start to understand about storage tank design.
You move directly to API 653 after that.
Some excellent companion books are:
Aboveground Storage Tanks by Philip Myers
Aboveground Storage Tanks: Practical Guide to Inspection, Maintenance and Repair by Brian Redman
Storage Tank Inspection Handbook by Wiley