I have been doing process safety my entire career and I have had some of the finest engineers teach me process safety. Now those that know me, know I am just some dumbass western KY edua-macated safety redneck, but even I know the importance of intenral inspections on my PVs. I know only two (2) RAGAGEPs for my PV inspection(s):
- API 510
- NBIC Part 2 – Inspection
I prefer API 510, but NBIC is certainly nothing to sneeze at. And guess what? Can you guess – THEY BOTH REQUIRE an internal inspection. And guess how often? THEY BOTH REQUIRE them at least every 10 years, unless our data says we can go longer. And here is the final kick-in-the-A_s… to extend the inspection frequency we have to have DATA and we can only get this data from… you guessed it – INTERNAL INSPECTIONS.
Now there will be some who will say I have crossed the line again and that I am crazy, but I also choose to play Russian Roulette with only 1 bullet!
Here are what these two (2) RAGAGEPs say:
API 510
6.5 Internal, On-stream, and Thickness Measurement Inspections
6.5.1 Inspection Interval
6.5.1.1 Unless justified by a RBI assessment, the period between internal or on-stream inspections and thickness measurement inspections SHALL NOT EXCEED ONE-HALF THE REMAINING LIFE OF THE VESSEL OR 10 YEARS, WHICHEVER IS LESS. Whenever the remaining life is LESS THAN four years, the inspection interval may be the full remaining life up to a maximum of two years. The interval is established by the inspector or engineer in accordance with the owner/user’s QA system.
NBIC Part 2 – Inspection
4.4.7 DETERMINING INSPECTION INTERVALS
a) The maximum period between internal inspections or a complete inservice evaluation of pressure-retaining items SHALL NOT EXCEED one-half of the estimated remaining service life of the vessel or TEN YEARS, WHICHEVER IS LESS. The method for estimating inspection intervals of pressure-retaining items subject to internal erosion or corrosion is discussed in NBIC Part 2, 4.4.7.1 and 4.4.7.2.
b) Inspection intervals can be REVISED BEYOND THE MAXIMUM PERIOD STATED ABOVE, provided the owner or user has submitted technical justification for revising the inspection interval, subject to review and acceptance by the Jurisdiction, where required.
c) Data used in engineering assessment methods to develop revised inspection intervals for pressure-retaining items shall be re-evaluated every five years, when a change in operation occurs, or after discovery of new and/or altered damage mechanisms.