The inspections should be focused on conditions that would present a concern.  These might be leakage, pitting corrosion, cracking of welds, etc.  I would start with a good visual inspection of all accessible surfaces for evidence of pitting, weld cracking, staining that might indicate areas of leakage, corrosion/wastage of base material, etc.  You might pressurize the system and do a leakage test with a soapy solution on welds or connections.  If you see any pitting corrosion, you might measure the depth of the pits.  These are all just common sense areas of inspection.  Don't make it harder than it needs to be.

Try here?
http://www.astm.org/cgi-bin/SoftCart.exe/DIGITAL_LIBRARY/STP/PAGES/STP33796S.htm?E+mystore

The best way to test something is to squeeze it, slowly, until it breaks!