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A questioning attitude is a trait that all engineers should cultivate. Most scientific inventions have resulted from such an attitude, and the classic example is Sir Isaac Newton's story of developing the law of gravity while seeking the answer to the simple question of why an apple had fallen from a tree.
Each time a question is asked or a challenge arises, the problem should be viewed through a different lens. This opens up opportunities to uncover alternate solutions.
Pursuing solutions. A plant engineer sought advice on a new shell-and-tube exchanger that was being installed. The equipment manufacturer (EM) charged the shell-and-tube side with nitrogen at 5 psig before shipping, but the pressures dropped to 3 psig. As per site best practices, if a drop in pressure occurs, the exchanger must be hydrotested again. The drop in pressure could be the result of a temperature variation or a leak, so it was advised to leak test with nitrogen at 10 psig for 30 min, rather than performing a hydrotest. Upon completion ofthis test, the issue might have been considered closed, but further efforts to determine a comprehensive solution were made. Regardless of whether or not the exchanger leaked during testing, it was worth looking at the flange assembly practices followed by the EM. It was found that bolts on the body flanges were assembled to a stress of 35 ksi. It became obvious that they had not performed bolt assembly calculations as per ASME PCC-1 Appendix O, which would have resulted in a bolt assembly stress in the range 40 ksi-70 ksi. This presented an opportunity to correct the EM's practices.
Problem definition. To determine the right answers, a problem definition should be appropriately termed. A questioning attitude is a key attribute...