Ammonia refrigeration “diffuser tanks” have been around since the early 1990’s when the Uniform Fire Code (UFC) began requiring them. That means some of these tanks will be due for their Mechanical Integrity Inspection and this is when most facilities will realize that the process design does not lend itself for a safe means to enter this tank for an internal inspection. And yes, an internal inspection is REQUIRED on these atmospheric tanks when the facility is using the holy grail of atmospheric tank inspection RAGAGEPS… API 653, Tank Inspection, Repair, Alteration, and Reconstruction. Of course, there are other options for conducting atmospheric tank inspections, but those too will require some internal inspection on some fixed frequency. So what does this mean?
API 653 states…