Double wall Liquid Ammonia Tank Inspection

[azmanvai]

Hi All

In one of our facilities, we have one double-walled liquid Ammonia tank which was built to API 620. It has never been inspected internally for more than 20 years now. With 40,000 MT storage it quickly becomes a major risk for the facility. The questions:

1. Since it is built to API 620, can we use API 653 for the inspection frequency?
2. Is there any other code than API 653 that we can use for this type of tank?
3. Other than Amine SCC, what other damage mechanisms can be expected?
4. What is the best method to assess the above damage mechanisms from external?

Appreciate your thoughts on this. TQ

 

[Duwe6]

Yes, I would recommend using API 653 *and* RBI. Use Acoustic Emission for your testing method, used in lieu of an entry-based Inspx. Opening ammonia tanks tends to cause problems due to the oxygen you introduce. And you will indeed be looking for SCC.

 

[azmanvai]

Thank you Duwe6

I have since found an EFMA standard which is somewhat similar to API653. Have you heard of Phonon? Do you know if its any good compared to AE?