full capability of the NDE equipment must be prepared by the user and the
document is subject to API audits. For these reasons and many others, it’s a
good idea to have an experienced Level 3 in method involved from the beginning
of the buying process to final commissioning.
following items should be clearly stated in any NDE equipment quote you
receive. These items are listed in API 5CT as part of the NDE equipment
a. “Coverage calculation”. This calculation must use the PRF per transducer,
product speed, transducer beam width at the inspection point (not the crystal
size), number of transducers and other factors specific to the equipment design
(RPM of the test head for example).
b. “Capability for the intended wall thickness” is very critical for the
inspection. The documentation should ensure the mid-wall coverage with evidence
of detection of mid-wall defects along with the common OD and ID notches.
c. “Repeatability”. Run the same standardization piece at testing speed 10
times. Now verify the difference between the lowest and highest indication. For
a quality NDE equipment this difference should be under 10%.
d. “Transducer orientation”. Weld seam must be inspected from both sides. This
is the same with transverse notches if they are required by the product
Evidence of typical defects detected”. Is a must have from any NDE equipment
API voting member SC5 – RGNDTASTM voting member E07