Can anyone advise whether oil penetration testing is possible in pontoon type Alum internal Floating roofs? The deck seams are of bolted construction and are vapour tight.
Bolted deck seams are NOT vapor tight, whomever is feeding you this malarkey should be ashamed and not be trusted to give you advice. If you want to test the seams in a laboratory setting, see API MPMS Chapter 19.3 - testing a deck seam is not all that hard. Even a carefully clamped and sealed joint leaks some amount (yes, I have tested some). Actual deck seams are unlikely to be as good as the laboratory seams. Yes you can use an oil penetrant test, and it will show leaks in many places. Bear in mind that vapors will get through much smaller spaces, so what have you proved other than perhaps to encourage that particular installer to do a better job (but not being competitive on the next project if cost is the prime mover)? Welded seams ARE vapor tight and you can test them easily with VB or PT or MT.
Agree with IFRs, bolt connection is hard to be vapor-tight.
However, It a little weird that API 650 H.4.1.3 mentions seams are vapor-tight but H.4.3.1 allows seams to be connected by bolts.
Deck seams testing is mentioned by H.6.2.
It seems to alum floating roof is impossible to prudently pass the API 650 requirements.