03:15 Feb-01-2008 burhanudin sudharmin Engineering, Reliability and Integrity Eng Shell Malaysia Trading, Malaysia, Joined Jan 2008 54
Re: IRIS Though external defects are uncommon in finned tubes, it should be noted that externals are easily visually inspected. IRIS application are more generally used to determine remaining thickness of a tube.
Can the film be measured? Not likely using IRIS. The interface betwen the outside
wall of the inner tube and the film represents a significant density change. It is the
change in densities that trigger the return pulse that ends a measurement. No matter how
tightly the bond, even the most minor changes trigger a return pulse. It is this reason that even bonded bi-metallic tubes cannot be fully inspected using the IRIS unit.